[PATCH v6 00/13] add the latest exfat driver

[PATCH v6 00/13] add the latest exfat driver

[Namjae Jeon]

This adds the latest Samsung exfat driver to fs/exfat. This is an
implementation of the Microsoft exFAT specification. Previous versions
of this shipped with millions of Android phones, and a random previous
snaphot has been merged in drivers/staging/.

Compared to the sdfat driver shipped on the phones the following changes
have been made:

 - the support for vfat has been removed as that is already supported
   by fs/fat
 - driver has been renamed to exfat
 - the code has been refactored and clean up to fully integrate into
   the upstream Linux version and follow the Linux coding style
 - metadata operations like create, lookup and readdir have been further
   optimized
 - various major and minor bugs have been fixed

We plan to treat this version as the future upstream for the code base
once merged, and all new features and bug fixes will go upstream first.

v6:
 - Fix always false comparison due to limited range of allow_utime's data
   type.
 - Move bh into loop in exfat_find_dir_entry().
 - Move entry_uniname and unichar variables into
   an if "entry_type == TYPE_EXTEND" branch.

v5:
 - Remove a blank line between the message and the error code in
   exfat_load_upcase_table.
 - Move brelse to the end of the while loop and rename release_bh label
   to free_table in exfat_load_upcase_table.
 - Move an error code assignment after a failed function call.
 - Rename labels and directly return instead of goto.
 - Improve the exception handling in exfat_get_dentry_set().
 - Remove ->d_time leftover.
 - fix boolreturn.cocci warnings.

v4:
 - Declare ALLOC_FAT_CHAIN and ALLOC_NO_FAT_CHAIN macros.
 - Rename labels with proper name.
 - Remove blank lines.
 - Remove pointer check for bh.
 - Move ep into loop in exfat_load_bitmap().
 - Replace READ/WRITE_ONCE() with test_and_clear_bit() and set_bit().
 - Change exfat_allow_set_time return type with bool.

v3:
 - fix wrong sbi->s_dirt set.

v2:
 - Check the bitmap count up to the total clusters.
 - Rename goto labels in several places.
 - Change time mode type with enumeration.
 - Directly return error instead of goto at first error check.
 - Combine seq_printf calls into a single one.

Namjae Jeon (13):
  exfat: add in-memory and on-disk structures and headers
  exfat: add super block operations
  exfat: add inode operations
  exfat: add directory operations
  exfat: add file operations
  exfat: add exfat entry operations
  exfat: add bitmap operations
  exfat: add exfat cache
  exfat: add misc operations
  exfat: add nls operations
  exfat: add Kconfig and Makefile
  exfat: add exfat in fs/Kconfig and fs/Makefile
  MAINTAINERS: add exfat filesystem

 MAINTAINERS          |    7 +
 fs/Kconfig           |    3 +-
 fs/Makefile          |    1 +
 fs/exfat/Kconfig     |   21 +
 fs/exfat/Makefile    |    8 +
 fs/exfat/balloc.c    |  272 ++++++++
 fs/exfat/cache.c     |  325 ++++++++++
 fs/exfat/dir.c       | 1310 +++++++++++++++++++++++++++++++++++++
 fs/exfat/exfat_fs.h  |  538 ++++++++++++++++
 fs/exfat/exfat_raw.h |  191 ++++++
 fs/exfat/fatent.c    |  472 ++++++++++++++
 fs/exfat/file.c      |  343 ++++++++++
 fs/exfat/inode.c     |  693 ++++++++++++++++++++
 fs/exfat/misc.c      |  240 +++++++
 fs/exfat/namei.c     | 1459 ++++++++++++++++++++++++++++++++++++++++++
 fs/exfat/nls.c       |  808 +++++++++++++++++++++++
 fs/exfat/super.c     |  738 +++++++++++++++++++++
 17 files changed, 7428 insertions(+), 1 deletion(-)
 create mode 100644 fs/exfat/Kconfig
 create mode 100644 fs/exfat/Makefile
 create mode 100644 fs/exfat/balloc.c
 create mode 100644 fs/exfat/cache.c
 create mode 100644 fs/exfat/dir.c
 create mode 100644 fs/exfat/exfat_fs.h
 create mode 100644 fs/exfat/exfat_raw.h
 create mode 100644 fs/exfat/fatent.c
 create mode 100644 fs/exfat/file.c
 create mode 100644 fs/exfat/inode.c
 create mode 100644 fs/exfat/misc.c
 create mode 100644 fs/exfat/namei.c
 create mode 100644 fs/exfat/nls.c
 create mode 100644 fs/exfat/super.c

-- 
2.17.1

[PATCH v6 01/13] exfat: add in-memory and on-disk structures and headers

[Namjae Jeon]

This adds in-memory and on-disk structures and headers.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/exfat_fs.h  | 538 +++++++++++++++++++++++++++++++++++++++++++
 fs/exfat/exfat_raw.h | 191 +++++++++++++++
 2 files changed, 729 insertions(+)
 create mode 100644 fs/exfat/exfat_fs.h
 create mode 100644 fs/exfat/exfat_raw.h

diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
new file mode 100644
index 000000000000..8222aa47e0dc
--- /dev/null
+++ b/fs/exfat/exfat_fs.h
@@ -0,0 +1,538 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#ifndef _EXFAT_H
+#define _EXFAT_H
+
+#include <linux/fs.h>
+#include <linux/ratelimit.h>
+
+#define EXFAT_SUPER_MAGIC       (0x2011BAB0UL)
+#define EXFAT_ROOT_INO		1
+
+enum exfat_time_mode {
+	TM_CREATE,
+	TM_MODIFY,
+	TM_ACCESS,
+};
+
+/*
+ * exfat error flags
+ */
+enum exfat_error_mode {
+	EXFAT_ERRORS_CONT,	/* ignore error and continue */
+	EXFAT_ERRORS_PANIC,	/* panic on error */
+	EXFAT_ERRORS_RO,	/* remount r/o on error */
+};
+
+/*
+ * exfat nls lossy flag
+ */
+enum {
+	NLS_NAME_NO_LOSSY,	/* no lossy */
+	NLS_NAME_LOSSY,		/* just detected incorrect filename(s) */
+	NLS_NAME_OVERLEN,	/* the length is over than its limit */
+};
+
+/*
+ * exfat common MACRO
+ */
+#define CLUSTER_32(x)	((unsigned int)((x) & 0xFFFFFFFFU))
+#define EOF_CLUSTER	CLUSTER_32(~0)
+#define BAD_CLUSTER	(0xFFFFFFF7U)
+#define FREE_CLUSTER	(0)
+#define BASE_CLUSTER	(2)
+
+#define EXFAT_HASH_BITS		8
+#define EXFAT_HASH_SIZE		(1UL << EXFAT_HASH_BITS)
+
+/*
+ * Type Definitions
+ */
+#define ES_2_ENTRIES	2
+#define ES_ALL_ENTRIES	0
+
+#define DIR_DELETED	0xFFFF0321
+
+/* type values */
+#define TYPE_UNUSED		0x0000
+#define TYPE_DELETED		0x0001
+#define TYPE_INVALID		0x0002
+#define TYPE_CRITICAL_PRI	0x0100
+#define TYPE_BITMAP		0x0101
+#define TYPE_UPCASE		0x0102
+#define TYPE_VOLUME		0x0103
+#define TYPE_DIR		0x0104
+#define TYPE_FILE		0x011F
+#define TYPE_CRITICAL_SEC	0x0200
+#define TYPE_STREAM		0x0201
+#define TYPE_EXTEND		0x0202
+#define TYPE_ACL		0x0203
+#define TYPE_BENIGN_PRI		0x0400
+#define TYPE_GUID		0x0401
+#define TYPE_PADDING		0x0402
+#define TYPE_ACLTAB		0x0403
+#define TYPE_BENIGN_SEC		0x0800
+#define TYPE_ALL		0x0FFF
+
+#define MAX_CHARSET_SIZE	6 /* max size of multi-byte character */
+#define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */
+#define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
+
+#define FAT_CACHE_SIZE		128
+#define FAT_CACHE_HASH_SIZE	64
+#define BUF_CACHE_SIZE		256
+#define BUF_CACHE_HASH_SIZE	64
+
+#define EXFAT_HINT_NONE		-1
+#define EXFAT_MIN_SUBDIR	2
+
+/*
+ * helpers for cluster size to byte conversion.
+ */
+#define EXFAT_CLU_TO_B(b, sbi)		((b) << (sbi)->cluster_size_bits)
+#define EXFAT_B_TO_CLU(b, sbi)		((b) >> (sbi)->cluster_size_bits)
+#define EXFAT_B_TO_CLU_ROUND_UP(b, sbi)	\
+	(((b - 1) >> (sbi)->cluster_size_bits) + 1)
+#define EXFAT_CLU_OFFSET(off, sbi)	((off) & ((sbi)->cluster_size - 1))
+
+/*
+ * helpers for block size to byte conversion.
+ */
+#define EXFAT_BLK_TO_B(b, sb)		((b) << (sb)->s_blocksize_bits)
+#define EXFAT_B_TO_BLK(b, sb)		((b) >> (sb)->s_blocksize_bits)
+#define EXFAT_B_TO_BLK_ROUND_UP(b, sb)	\
+	(((b - 1) >> (sb)->s_blocksize_bits) + 1)
+#define EXFAT_BLK_OFFSET(off, sb)	((off) & ((sb)->s_blocksize - 1))
+
+/*
+ * helpers for block size to dentry size conversion.
+ */
+#define EXFAT_B_TO_DEN_IDX(b, sbi)	\
+	((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
+#define EXFAT_B_TO_DEN(b)		((b) >> DENTRY_SIZE_BITS)
+#define EXFAT_DEN_TO_B(b)		((b) << DENTRY_SIZE_BITS)
+
+#define EXFAT_SB_DIRTY		0
+
+struct exfat_timestamp {
+	unsigned short sec;	/* 0 ~ 59 */
+	unsigned short min;	/* 0 ~ 59 */
+	unsigned short hour;	/* 0 ~ 23 */
+	unsigned short day;	/* 1 ~ 31 */
+	unsigned short mon;	/* 1 ~ 12 */
+	unsigned short year;	/* 0 ~ 127 (since 1980) */
+};
+
+struct exfat_date_time {
+	unsigned short year;
+	unsigned short month;
+	unsigned short day;
+	unsigned short hour;
+	unsigned short minute;
+	unsigned short second;
+	unsigned short milli_second;
+};
+
+struct exfat_dentry_namebuf {
+	char *lfn;
+	int lfnbuf_len; /* usally MAX_UNINAME_BUF_SIZE */
+};
+
+/* unicode name structure */
+struct exfat_uni_name {
+	/* +3 for null and for converting */
+	unsigned short name[MAX_NAME_LENGTH + 3];
+	unsigned short name_hash;
+	unsigned char name_len;
+};
+
+/* directory structure */
+struct exfat_chain {
+	unsigned int dir;
+	unsigned int size;
+	unsigned char flags;
+};
+
+/* first empty entry hint information */
+struct exfat_hint_femp {
+	/* entry index of a directory */
+	int eidx;
+	/* count of continuous empty entry */
+	int count;
+	/* the cluster that first empty slot exists in */
+	struct exfat_chain cur;
+};
+
+/* hint structure */
+struct exfat_hint {
+	unsigned int clu;
+	union {
+		unsigned int off; /* cluster offset */
+		int eidx; /* entry index */
+	};
+};
+
+struct exfat_entry_set_cache {
+	/* sector number that contains file_entry */
+	sector_t sector;
+	/* byte offset in the sector */
+	unsigned int offset;
+	/* flag in stream entry. 01 for cluster chain, 03 for contig. */
+	int alloc_flag;
+	unsigned int num_entries;
+	struct exfat_dentry entries[];
+};
+
+struct exfat_dir_entry {
+	struct exfat_chain dir;
+	int entry;
+	unsigned int type;
+	unsigned int start_clu;
+	unsigned char flags;
+	unsigned short attr;
+	loff_t size;
+	unsigned int num_subdirs;
+	struct exfat_date_time create_timestamp;
+	struct exfat_date_time modify_timestamp;
+	struct exfat_date_time access_timestamp;
+	struct exfat_dentry_namebuf namebuf;
+};
+
+/*
+ * exfat mount in-memory data
+ */
+struct exfat_mount_options {
+	kuid_t fs_uid;
+	kgid_t fs_gid;
+	unsigned short fs_fmask;
+	unsigned short fs_dmask;
+	/* permission for setting the [am]time */
+	unsigned short allow_utime;
+	/* charset for filename input/display */
+	char *iocharset;
+	unsigned char utf8;
+	unsigned char case_sensitive;
+	unsigned char tz_utc;
+	/* on error: continue, panic, remount-ro */
+	enum exfat_error_mode errors;
+	/* flag on if -o dicard specified and device support discard() */
+	unsigned char discard;
+};
+
+/*
+ * EXFAT file system superblock in-memory data
+ */
+struct exfat_sb_info {
+	unsigned int vol_type; /* volume FAT type */
+	unsigned int vol_id; /* volume serial number */
+	unsigned long long num_sectors; /* num of sectors in volume */
+	unsigned int num_clusters; /* num of clusters in volume */
+	unsigned int cluster_size; /* cluster size in bytes */
+	unsigned int cluster_size_bits;
+	unsigned int sect_per_clus; /* cluster size in sectors */
+	unsigned int sect_per_clus_bits;
+	unsigned long long FAT1_start_sector; /* FAT1 start sector */
+	unsigned long long FAT2_start_sector; /* FAT2 start sector */
+	unsigned long long root_start_sector; /* root dir start sector */
+	unsigned long long data_start_sector; /* data area start sector */
+	unsigned int num_FAT_sectors; /* num of FAT sectors */
+	unsigned int root_dir; /* root dir cluster */
+	unsigned int dentries_in_root; /* num of dentries in root dir */
+	unsigned int dentries_per_clu; /* num of dentries per cluster */
+	unsigned int vol_flag; /* volume dirty flag */
+	struct buffer_head *pbr_bh; /* buffer_head of PBR sector */
+
+	unsigned int map_clu; /* allocation bitmap start cluster */
+	unsigned int map_sectors; /* num of allocation bitmap sectors */
+	struct buffer_head **vol_amap; /* allocation bitmap */
+
+	unsigned short *vol_utbl; /* upcase table */
+
+	unsigned int clu_srch_ptr; /* cluster search pointer */
+	unsigned int used_clusters; /* number of used clusters */
+
+	unsigned long s_state;
+	struct mutex s_lock; /* superblock lock */
+	struct super_block *host_sb; /* sb pointer */
+	struct exfat_mount_options options;
+	struct nls_table *nls_io; /* Charset used for input and display */
+	struct ratelimit_state ratelimit;
+
+	spinlock_t inode_hash_lock;
+	struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
+};
+
+/*
+ * EXFAT file system inode in-memory data
+ */
+struct exfat_inode_info {
+	struct exfat_chain dir;
+	int entry;
+	unsigned int type;
+	unsigned short attr;
+	unsigned int start_clu;
+	unsigned char flags;
+	/*
+	 * the copy of low 32bit of i_version to check
+	 * the validation of hint_stat.
+	 */
+	unsigned int version;
+	/* file offset or dentry index for readdir */
+	loff_t rwoffset;
+
+	/* hint for cluster last accessed */
+	struct exfat_hint hint_bmap;
+	/* hint for entry index we try to lookup next time */
+	struct exfat_hint hint_stat;
+	/* hint for first empty entry */
+	struct exfat_hint_femp hint_femp;
+
+	spinlock_t cache_lru_lock;
+	struct list_head cache_lru;
+	int nr_caches;
+	/* for avoiding the race between alloc and free */
+	unsigned int cache_valid_id;
+
+	/*
+	 * NOTE: i_size_ondisk is 64bits, so must hold ->inode_lock to access.
+	 * physically allocated size.
+	 */
+	loff_t i_size_ondisk;
+	/* block-aligned i_size (used in cont_write_begin) */
+	loff_t i_size_aligned;
+	/* on-disk position of directory entry or 0 */
+	loff_t i_pos;
+	/* hash by i_location */
+	struct hlist_node i_hash_fat;
+	/* protect bmap against truncate */
+	struct rw_semaphore truncate_lock;
+	struct inode vfs_inode;
+};
+
+static inline struct exfat_sb_info *EXFAT_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
+{
+	return container_of(inode, struct exfat_inode_info, vfs_inode);
+}
+
+/*
+ * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to
+ * save ATTR_RO instead of ->i_mode.
+ *
+ * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
+ * bit, it's just used as flag for app.
+ */
+static inline int exfat_mode_can_hold_ro(struct inode *inode)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
+
+	if (S_ISDIR(inode->i_mode))
+		return 0;
+
+	if ((~sbi->options.fs_fmask) & 0222)
+		return 1;
+	return 0;
+}
+
+/* Convert attribute bits and a mask to the UNIX mode. */
+static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
+		unsigned short attr, mode_t mode)
+{
+	if ((attr & ATTR_READONLY) && !(attr & ATTR_SUBDIR))
+		mode &= ~0222;
+
+	if (attr & ATTR_SUBDIR)
+		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
+
+	return (mode & ~sbi->options.fs_fmask) | S_IFREG;
+}
+
+/* Return the FAT attribute byte for this inode */
+static inline unsigned short exfat_make_attr(struct inode *inode)
+{
+	unsigned short attr = EXFAT_I(inode)->attr;
+
+	if (S_ISDIR(inode->i_mode))
+		attr |= ATTR_SUBDIR;
+	if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
+		attr |= ATTR_READONLY;
+	return attr;
+}
+
+static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
+{
+	if (exfat_mode_can_hold_ro(inode))
+		EXFAT_I(inode)->attr = attr & (ATTR_RWMASK | ATTR_READONLY);
+	else
+		EXFAT_I(inode)->attr = attr & ATTR_RWMASK;
+}
+
+static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,
+		sector_t sec)
+{
+	return ((sec - sbi->data_start_sector + 1) &
+			((1 << sbi->sect_per_clus_bits) - 1)) == 0;
+}
+
+static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
+		unsigned int clus)
+{
+	return ((clus - BASE_CLUSTER) << sbi->sect_per_clus_bits)
+			+ sbi->data_start_sector;
+}
+
+static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
+		sector_t sec)
+{
+	return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
+			BASE_CLUSTER;
+}
+
+/* super.c */
+int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag);
+
+/* fatent.c */
+#define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
+
+int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
+		struct exfat_chain *p_chain);
+int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
+int exfat_ent_get(struct super_block *sb, unsigned int loc,
+		unsigned int *content);
+int exfat_ent_set(struct super_block *sb, unsigned int loc,
+		unsigned int content);
+int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
+		int entry, struct exfat_dentry *p_entry);
+int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
+		unsigned int len);
+struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
+		struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
+		sector_t *sector);
+struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
+		struct exfat_chain *p_dir, int entry, unsigned int type,
+		struct exfat_dentry **file_ep);
+int exfat_zeroed_cluster(struct inode *dir, unsigned int clu);
+int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
+		int entry, sector_t *sector, int *offset);
+int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
+		unsigned int *ret_clu);
+int exfat_mirror_bh(struct super_block *sb, sector_t sec,
+		struct buffer_head *bh);
+int exfat_count_num_clusters(struct super_block *sb,
+		struct exfat_chain *p_chain, unsigned int *ret_count);
+int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
+
+/* balloc.c */
+int exfat_load_bitmap(struct super_block *sb);
+void exfat_free_bitmap(struct super_block *sb);
+int exfat_set_bitmap(struct inode *inode, unsigned int clu);
+void exfat_clear_bitmap(struct inode *inode, unsigned int clu);
+unsigned int exfat_test_bitmap(struct super_block *sb, unsigned int clu);
+int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
+
+/* file.c */
+extern const struct file_operations exfat_file_operations;
+int __exfat_truncate(struct inode *inode, loff_t new_size);
+void exfat_truncate(struct inode *inode, loff_t size);
+int exfat_setattr(struct dentry *dentry, struct iattr *attr);
+int exfat_getattr(const struct path *path, struct kstat *stat,
+		unsigned int request_mask, unsigned int query_flags);
+
+/* namei.c */
+extern const struct dentry_operations exfat_dentry_ops;
+extern const struct dentry_operations exfat_ci_dentry_ops;
+int exfat_find_empty_entry(struct inode *inode, struct exfat_chain *p_dir,
+		int num_entries);
+
+/* cache.c */
+int exfat_cache_init(void);
+void exfat_cache_shutdown(void);
+void exfat_cache_init_inode(struct inode *inode);
+void exfat_cache_inval_inode(struct inode *inode);
+int exfat_get_cluster(struct inode *inode, unsigned int cluster,
+		unsigned int *fclus, unsigned int *dclus,
+		unsigned int *last_dclus, int allow_eof);
+
+/* dir.c */
+extern const struct inode_operations exfat_dir_inode_operations;
+extern const struct file_operations exfat_dir_operations;
+void exfat_get_uniname_from_ext_entry(struct super_block *sb,
+		struct exfat_chain *p_dir, int entry, unsigned short *uniname);
+unsigned int exfat_get_entry_type(struct exfat_dentry *p_entry);
+void exfat_get_entry_time(struct exfat_dentry *p_entry,
+		struct exfat_timestamp *tp, unsigned char mode);
+void exfat_set_entry_time(struct exfat_dentry *p_entry,
+		struct exfat_timestamp *tp, unsigned char mode);
+int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
+		int entry, unsigned int type, unsigned int start_clu,
+		unsigned long long size);
+int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
+		int entry, int num_entries, struct exfat_uni_name *p_uniname);
+int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
+		int entry, int order, int num_entries);
+int update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
+		int entry);
+int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
+		struct exfat_entry_set_cache *es, int sync);
+int exfat_get_num_entries(struct exfat_uni_name *p_uniname);
+int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
+		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
+		int num_entries, unsigned int type);
+int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
+
+/* inode.c */
+extern const struct inode_operations exfat_file_inode_operations;
+void exfat_sync_inode(struct inode *inode);
+struct inode *exfat_build_inode(struct super_block *sb,
+		struct exfat_dir_entry *info, loff_t i_pos);
+void exfat_hash_inode(struct inode *inode, loff_t i_pos);
+void exfat_unhash_inode(struct inode *inode);
+void exfat_truncate(struct inode *inode, loff_t size);
+struct inode *exfat_iget(struct super_block *sb, loff_t i_pos);
+int exfat_write_inode(struct inode *inode, struct writeback_control *wbc);
+void exfat_evict_inode(struct inode *inode);
+int exfat_read_inode(struct inode *inode, struct exfat_dir_entry *info);
+
+/* exfat/nls.c */
+int exfat_nls_cmp_uniname(struct super_block *sb, unsigned short *a,
+		unsigned short *b);
+int exfat_nls_uni16s_to_vfsname(struct super_block *sb,
+		struct exfat_uni_name *uniname, unsigned char *p_cstring,
+		int len);
+int exfat_nls_vfsname_to_uni16s(struct super_block *sb,
+		const unsigned char *p_cstring, const int len,
+		struct exfat_uni_name *uniname, int *p_lossy);
+int exfat_create_upcase_table(struct super_block *sb);
+void exfat_free_upcase_table(struct super_block *sb);
+
+/* exfat/misc.c */
+void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
+		__printf(3, 4) __cold;
+#define exfat_fs_error(sb, fmt, args...)          \
+		__exfat_fs_error(sb, 1, fmt, ## args)
+#define exfat_fs_error_ratelimit(sb, fmt, args...) \
+		__exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
+		fmt, ## args)
+void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
+		__printf(3, 4) __cold;
+void exfat_time_fat2unix(struct exfat_sb_info *sbi, struct timespec64 *ts,
+		struct exfat_date_time *tp);
+void exfat_time_unix2fat(struct exfat_sb_info *sbi, struct timespec64 *ts,
+		struct exfat_date_time *tp);
+struct exfat_timestamp *exfat_tm_now(struct exfat_sb_info *sbi,
+		struct exfat_timestamp *tm);
+unsigned short exfat_calc_chksum_2byte(void *data, int len,
+		unsigned short chksum, int type);
+void exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int sync);
+void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
+		unsigned int size, unsigned char flags);
+void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec);
+
+#endif /* !_EXFAT_H */
diff --git a/fs/exfat/exfat_raw.h b/fs/exfat/exfat_raw.h
new file mode 100644
index 000000000000..d345ffef4037
--- /dev/null
+++ b/fs/exfat/exfat_raw.h
@@ -0,0 +1,191 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#ifndef _EXFAT_RAW_H
+#define _EXFAT_RAW_H
+
+#include <linux/types.h>
+
+#define PBR_SIGNATURE		0xAA55
+
+#define VOL_CLEAN		0x0000
+#define VOL_DIRTY		0x0002
+
+/* AllocationPossible and NoFatChain field in GeneralSecondaryFlags Field */
+#define ALLOC_FAT_CHAIN		0x01
+#define ALLOC_NO_FAT_CHAIN	0x03
+
+#define DENTRY_SIZE		32 /* directory entry size */
+#define DENTRY_SIZE_BITS	5
+/* exFAT allows 8388608(256MB) directory entries */
+#define MAX_EXFAT_DENTRIES	8388608
+
+/* dentry types */
+#define EXFAT_UNUSED		0x00	/* end of directory */
+#define EXFAT_DELETE		~(0x80)
+#define IS_EXFAT_DELETED(x)	((x) < 0x80) /* deleted file (0x01~0x7F) */
+#define EXFAT_INVAL		0x80	/* invalid value */
+#define EXFAT_BITMAP		0x81	/* allocation bitmap */
+#define EXFAT_UPCASE		0x82	/* upcase table */
+#define EXFAT_VOLUME		0x83	/* volume label */
+#define EXFAT_FILE		0x85	/* file or dir */
+#define EXFAT_GUID		0xA0
+#define EXFAT_PADDING		0xA1
+#define EXFAT_ACLTAB		0xA2
+#define EXFAT_STREAM		0xC0	/* stream entry */
+#define EXFAT_NAME		0xC1	/* file name entry */
+#define EXFAT_ACL		0xC2	/* stream entry */
+
+/* checksum types */
+#define CS_DIR_ENTRY		0
+#define CS_PBR_SECTOR		1
+#define CS_DEFAULT		2
+
+/* file attributes */
+#define ATTR_READONLY		0x0001
+#define ATTR_HIDDEN		0x0002
+#define ATTR_SYSTEM		0x0004
+#define ATTR_VOLUME		0x0008
+#define ATTR_SUBDIR		0x0010
+#define ATTR_ARCHIVE		0x0020
+#define ATTR_EXTEND		(ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM | \
+				 ATTR_VOLUME) /* 0x000F */
+
+#define ATTR_EXTEND_MASK	(ATTR_EXTEND | ATTR_SUBDIR | ATTR_ARCHIVE)
+#define ATTR_RWMASK		(ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME | \
+				 ATTR_SUBDIR | ATTR_ARCHIVE)
+
+#define ATTR_READONLY_LE	cpu_to_le16(0x0001)
+#define ATTR_HIDDEN_LE		cpu_to_le16(0x0002)
+#define ATTR_SYSTEM_LE		cpu_to_le16(0x0004)
+#define ATTR_VOLUME_LE		cpu_to_le16(0x0008)
+#define ATTR_SUBDIR_LE		cpu_to_le16(0x0010)
+#define ATTR_ARCHIVE_LE		cpu_to_le16(0x0020)
+
+/* EXFAT BIOS parameter block (64 bytes) */
+struct bpb64 {
+	__u8 jmp_boot[3];
+	__u8 oem_name[8];
+	__u8 res_zero[53];
+};
+
+/* EXFAT EXTEND BIOS parameter block (56 bytes) */
+struct bsx64 {
+	__le64 vol_offset;
+	__le64 vol_length;
+	__le32 fat_offset;
+	__le32 fat_length;
+	__le32 clu_offset;
+	__le32 clu_count;
+	__le32 root_cluster;
+	__le32 vol_serial;
+	__u8 fs_version[2];
+	__le16 vol_flags;
+	__u8 sect_size_bits;
+	__u8 sect_per_clus_bits;
+	__u8 num_fats;
+	__u8 phy_drv_no;
+	__u8 perc_in_use;
+	__u8 reserved2[7];
+};
+
+/* EXFAT PBR[BPB+BSX] (120 bytes) */
+struct pbr64 {
+	struct bpb64 bpb;
+	struct bsx64 bsx;
+};
+
+/* Common PBR[Partition Boot Record] (512 bytes) */
+struct pbr {
+	union {
+		__u8 raw[64];
+		struct bpb64 f64;
+	} bpb;
+	union {
+		__u8 raw[56];
+		struct bsx64 f64;
+	} bsx;
+	__u8 boot_code[390];
+	__le16 signature;
+};
+
+struct exfat_dentry {
+	__u8 type;
+	union {
+		struct {
+			__u8 num_ext;
+			__le16 checksum;
+			__le16 attr;
+			__le16 reserved1;
+			__le16 create_time;
+			__le16 create_date;
+			__le16 modify_time;
+			__le16 modify_date;
+			__le16 access_time;
+			__le16 access_date;
+			__u8 create_time_ms;
+			__u8 modify_time_ms;
+			__u8 access_time_ms;
+			__u8 reserved2[9];
+		} __packed file; /* file directory entry */
+		struct {
+			__u8 flags;
+			__u8 reserved1;
+			__u8 name_len;
+			__le16 name_hash;
+			__le16 reserved2;
+			__le64 valid_size;
+			__le32 reserved3;
+			__le32 start_clu;
+			__le64 size;
+		} __packed stream; /* stream extension directory entry */
+		struct {
+			__u8 flags;
+			__le16 unicode_0_14[15];
+		} __packed name; /* file name directory entry */
+		struct {
+			__u8 flags;
+			__u8 reserved[18];
+			__le32 start_clu;
+			__le64 size;
+		} __packed bitmap; /* allocation bitmap directory entry */
+		struct {
+			__u8 reserved1[3];
+			__le32 checksum;
+			__u8 reserved2[12];
+			__le32 start_clu;
+			__le64 size;
+		} __packed upcase; /* up-case table directory entry */
+	} __packed dentry;
+} __packed;
+
+#define file_num_ext			dentry.file.num_ext
+#define file_checksum			dentry.file.checksum
+#define file_attr			dentry.file.attr
+#define file_create_time		dentry.file.create_time
+#define file_create_date		dentry.file.create_date
+#define file_modify_time		dentry.file.modify_time
+#define file_modify_date		dentry.file.modify_date
+#define file_access_time		dentry.file.access_time
+#define file_access_date		dentry.file.access_date
+#define file_create_time_ms		dentry.file.create_time_ms
+#define file_modify_time_ms		dentry.file.modify_time_ms
+#define file_access_time_ms		dentry.file.access_time_ms
+#define stream_flags			dentry.stream.flags
+#define stream_name_len			dentry.stream.name_len
+#define stream_name_hash		dentry.stream.name_hash
+#define stream_start_clu		dentry.stream.start_clu
+#define stream_valid_size		dentry.stream.valid_size
+#define stream_size			dentry.stream.size
+#define name_flags			dentry.name.flags
+#define name_unicode			dentry.name.unicode_0_14
+#define bitmap_flags			dentry.bitmap.flags
+#define bitmap_start_clu		dentry.bitmap.start_clu
+#define bitmap_size			dentry.bitmap.size
+#define upcase_start_clu		dentry.upcase.start_clu
+#define upcase_size			dentry.upcase.size
+#define upcase_checksum			dentry.upcase.checksum
+
+#endif /* !_EXFAT_RAW_H */
-- 
2.17.1

[PATCH v6 02/13] exfat: add super block operations

[Namjae Jeon]

This adds the implementation of superblock operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/super.c | 738 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 738 insertions(+)
 create mode 100644 fs/exfat/super.c

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
new file mode 100644
index 000000000000..f5d5144bd72a
--- /dev/null
+++ b/fs/exfat/super.c
@@ -0,0 +1,738 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/mount.h>
+#include <linux/cred.h>
+#include <linux/statfs.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+#include <linux/fs_struct.h>
+#include <linux/iversion.h>
+#include <linux/nls.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static char exfat_default_iocharset[] = CONFIG_EXFAT_FS_DEFAULT_IOCHARSET;
+static const char exfat_iocharset_with_utf8[] = "iso8859-1";
+static struct kmem_cache *exfat_inode_cachep;
+
+static void exfat_free_iocharset(struct exfat_sb_info *sbi)
+{
+	if (sbi->options.iocharset != exfat_default_iocharset)
+		kfree(sbi->options.iocharset);
+}
+
+static void exfat_put_super(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	mutex_lock(&sbi->s_lock);
+	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
+		sync_blockdev(sb->s_bdev);
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+	exfat_free_upcase_table(sb);
+	exfat_free_bitmap(sb);
+	mutex_unlock(&sbi->s_lock);
+
+	if (sbi->nls_io) {
+		unload_nls(sbi->nls_io);
+		sbi->nls_io = NULL;
+	}
+	exfat_free_iocharset(sbi);
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+}
+
+static int exfat_sync_fs(struct super_block *sb, int wait)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int err = 0;
+
+	/* If there are some dirty buffers in the bdev inode */
+	mutex_lock(&sbi->s_lock);
+	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
+		sync_blockdev(sb->s_bdev);
+		if (exfat_set_vol_flags(sb, VOL_CLEAN))
+			err = -EIO;
+	}
+	mutex_unlock(&sbi->s_lock);
+	return err;
+}
+
+static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	if (sbi->used_clusters == ~0u) {
+		mutex_lock(&sbi->s_lock);
+		if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
+			mutex_unlock(&sbi->s_lock);
+			return -EIO;
+		}
+		mutex_unlock(&sbi->s_lock);
+	}
+
+	buf->f_type = sb->s_magic;
+	buf->f_bsize = sbi->cluster_size;
+	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
+	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
+	buf->f_bavail = buf->f_bfree;
+	buf->f_fsid.val[0] = (unsigned int)id;
+	buf->f_fsid.val[1] = (unsigned int)(id >> 32);
+	buf->f_namelen = 260;
+	return 0;
+}
+
+static int __exfat_set_vol_flags(struct super_block *sb,
+		unsigned short new_flag, int always_sync)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct pbr64 *bpb;
+	int sync = 0;
+
+	/* flags are not changed */
+	if (sbi->vol_flag == new_flag)
+		return 0;
+
+	sbi->vol_flag = new_flag;
+
+	/* skip updating volume dirty flag,
+	 * if this volume has been mounted with read-only
+	 */
+	if (sb_rdonly(sb))
+		return 0;
+
+	if (!sbi->pbr_bh) {
+		sbi->pbr_bh = sb_bread(sb, 0);
+		if (!sbi->pbr_bh) {
+			exfat_msg(sb, KERN_ERR, "failed to read boot sector");
+			return -ENOMEM;
+		}
+	}
+
+	bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
+	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
+
+	if (always_sync)
+		sync = 1;
+	else if ((new_flag == VOL_DIRTY) && (!buffer_dirty(sbi->pbr_bh)))
+		sync = 1;
+	else
+		sync = 0;
+
+	set_buffer_uptodate(sbi->pbr_bh);
+	mark_buffer_dirty(sbi->pbr_bh);
+
+	if (sync)
+		sync_dirty_buffer(sbi->pbr_bh);
+	return 0;
+}
+
+int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
+{
+	return __exfat_set_vol_flags(sb, new_flag, 0);
+}
+
+static int exfat_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_mount_options *opts = &sbi->options;
+
+	/* Show partition info */
+	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
+		seq_printf(m, ",uid=%u",
+				from_kuid_munged(&init_user_ns, opts->fs_uid));
+	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
+		seq_printf(m, ",gid=%u",
+				from_kgid_munged(&init_user_ns, opts->fs_gid));
+	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
+	if (opts->allow_utime)
+		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
+	if (sbi->nls_io)
+		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+	if (opts->utf8)
+		seq_puts(m, ",utf8");
+	seq_printf(m, ",case_sensitive=%u", opts->case_sensitive);
+	if (opts->tz_utc)
+		seq_puts(m, ",tz=UTC");
+	seq_printf(m, ",bps=%ld", sb->s_blocksize);
+	if (opts->errors == EXFAT_ERRORS_CONT)
+		seq_puts(m, ",errors=continue");
+	else if (opts->errors == EXFAT_ERRORS_PANIC)
+		seq_puts(m, ",errors=panic");
+	else
+		seq_puts(m, ",errors=remount-ro");
+	if (opts->discard)
+		seq_puts(m, ",discard");
+	return 0;
+}
+
+static struct inode *exfat_alloc_inode(struct super_block *sb)
+{
+	struct exfat_inode_info *ei;
+
+	ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+
+	init_rwsem(&ei->truncate_lock);
+	return &ei->vfs_inode;
+}
+
+static void exfat_destroy_inode(struct inode *inode)
+{
+	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
+}
+
+static const struct super_operations exfat_sops = {
+	.alloc_inode   = exfat_alloc_inode,
+	.destroy_inode = exfat_destroy_inode,
+	.write_inode   = exfat_write_inode,
+	.evict_inode  = exfat_evict_inode,
+	.put_super     = exfat_put_super,
+	.sync_fs       = exfat_sync_fs,
+	.statfs        = exfat_statfs,
+	.show_options  = exfat_show_options,
+};
+
+enum {
+	Opt_uid,
+	Opt_gid,
+	Opt_umask,
+	Opt_dmask,
+	Opt_fmask,
+	Opt_allow_utime,
+	Opt_charset,
+	Opt_utf8,
+	Opt_case_sensitive,
+	Opt_tz,
+	Opt_errors,
+	Opt_discard,
+};
+
+static const struct fs_parameter_spec exfat_param_specs[] = {
+	fsparam_u32("uid",			Opt_uid),
+	fsparam_u32("gid",			Opt_gid),
+	fsparam_u32oct("umask",			Opt_umask),
+	fsparam_u32oct("dmask",			Opt_dmask),
+	fsparam_u32oct("fmask",			Opt_fmask),
+	fsparam_u32oct("allow_utime",		Opt_allow_utime),
+	fsparam_string("iocharset",		Opt_charset),
+	fsparam_flag("utf8",			Opt_utf8),
+	fsparam_flag("case_sensitive",		Opt_case_sensitive),
+	fsparam_string("tz",			Opt_tz),
+	fsparam_enum("errors",			Opt_errors),
+	fsparam_flag("discard",			Opt_discard),
+	{}
+};
+
+static const struct fs_parameter_enum exfat_param_enums[] = {
+	{ Opt_errors,	"continue",		EXFAT_ERRORS_CONT },
+	{ Opt_errors,	"panic",		EXFAT_ERRORS_PANIC },
+	{ Opt_errors,	"remount-ro",		EXFAT_ERRORS_RO },
+	{}
+};
+
+static const struct fs_parameter_description exfat_parameters = {
+	.name		= "exfat",
+	.specs		= exfat_param_specs,
+	.enums		= exfat_param_enums,
+};
+
+static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct exfat_sb_info *sbi = fc->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, &exfat_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
+		break;
+	case Opt_gid:
+		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
+		break;
+	case Opt_umask:
+		opts->fs_fmask = result.uint_32;
+		opts->fs_dmask = result.uint_32;
+		break;
+	case Opt_dmask:
+		opts->fs_dmask = result.uint_32;
+		break;
+	case Opt_fmask:
+		opts->fs_fmask = result.uint_32;
+		break;
+	case Opt_allow_utime:
+		opts->allow_utime = result.uint_32 & 0022;
+		break;
+	case Opt_charset:
+		exfat_free_iocharset(sbi);
+		opts->iocharset = kstrdup(param->string, GFP_KERNEL);
+		if (!opts->iocharset)
+			return -ENOMEM;
+		break;
+	case Opt_case_sensitive:
+		opts->case_sensitive = 1;
+		break;
+	case Opt_utf8:
+		opts->utf8 = 1;
+		break;
+	case Opt_tz:
+		if (!strcmp(param->string, "UTC"))
+			opts->tz_utc = 1;
+		break;
+	case Opt_errors:
+		opts->errors = result.uint_32;
+		break;
+	case Opt_discard:
+		opts->discard = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void exfat_hash_init(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->inode_hash_lock);
+	for (i = 0; i < EXFAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
+}
+
+static int exfat_read_root(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_chain cdir;
+	int num_subdirs, num_clu = 0;
+
+	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	ei->entry = -1;
+	ei->start_clu = sbi->root_dir;
+	ei->flags = ALLOC_FAT_CHAIN;
+	ei->type = TYPE_DIR;
+	ei->version = 0;
+	ei->rwoffset = 0;
+	ei->hint_bmap.off = EOF_CLUSTER;
+	ei->hint_stat.eidx = 0;
+	ei->hint_stat.clu = sbi->root_dir;
+	ei->hint_femp.eidx = EXFAT_HINT_NONE;
+
+	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
+		return -EIO;
+	i_size_write(inode, num_clu << sbi->cluster_size_bits);
+
+	num_subdirs = exfat_count_dir_entries(sb, &cdir);
+	if (num_subdirs < 0)
+		return -EIO;
+	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
+
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode_inc_iversion(inode);
+	inode->i_generation = 0;
+	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
+	inode->i_op = &exfat_dir_inode_operations;
+	inode->i_fop = &exfat_dir_operations;
+
+	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
+			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
+	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
+	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
+	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
+
+	exfat_save_attr(inode, ATTR_SUBDIR);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	exfat_cache_init_inode(inode);
+	return 0;
+}
+
+static bool is_exfat(struct pbr *pbr)
+{
+	int i = 53;
+
+	do {
+		if (pbr->bpb.f64.res_zero[i - 1])
+			break;
+	} while (--i);
+	return i ? false : true;
+}
+
+static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb,
+		struct buffer_head **prev_bh)
+{
+	struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data;
+	unsigned short logical_sect = 0;
+
+	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
+
+	if (!is_power_of_2(logical_sect) ||
+	    logical_sect < 512 || logical_sect > 4096) {
+		exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
+				logical_sect);
+		return NULL;
+	}
+
+	if (logical_sect < sb->s_blocksize) {
+		exfat_msg(sb, KERN_ERR,
+			"logical sector size too small for device (logical sector size = %u)",
+			logical_sect);
+		return NULL;
+	}
+
+	if (logical_sect > sb->s_blocksize) {
+		struct buffer_head *bh = NULL;
+
+		__brelse(*prev_bh);
+		*prev_bh = NULL;
+
+		if (!sb_set_blocksize(sb, logical_sect)) {
+			exfat_msg(sb, KERN_ERR,
+				"unable to set blocksize %u", logical_sect);
+			return NULL;
+		}
+		bh = sb_bread(sb, 0);
+		if (!bh) {
+			exfat_msg(sb, KERN_ERR,
+				"unable to read boot sector (logical sector size = %lu)",
+				sb->s_blocksize);
+			return NULL;
+		}
+
+		*prev_bh = bh;
+		p_pbr = (struct pbr *) bh->b_data;
+	}
+	return p_pbr;
+}
+
+/* mount the file system volume */
+static int __exfat_fill_super(struct super_block *sb)
+{
+	int ret;
+	struct pbr *p_pbr;
+	struct pbr64 *p_bpb;
+	struct buffer_head *bh;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	/* set block size to read super block */
+	sb_min_blocksize(sb, 512);
+
+	/* read boot sector */
+	bh = sb_bread(sb, 0);
+	if (!bh) {
+		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
+		return -EIO;
+	}
+
+	/* PRB is read */
+	p_pbr = (struct pbr *)bh->b_data;
+
+	/* check the validity of PBR */
+	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
+		exfat_msg(sb, KERN_ERR, "invalid boot record signature");
+		ret = -EINVAL;
+		goto free_bh;
+	}
+
+
+	/* check logical sector size */
+	p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh);
+	if (!p_pbr) {
+		ret = -EIO;
+		goto free_bh;
+	}
+
+	if (!is_exfat(p_pbr)) {
+		ret = -EINVAL;
+		goto free_bh;
+	}
+
+	/* set maximum file size for exFAT */
+	sb->s_maxbytes = 0x7fffffffffffffffLL;
+
+	p_bpb = (struct pbr64 *)p_pbr;
+	if (!p_bpb->bsx.num_fats) {
+		exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
+		ret = -EINVAL;
+		goto free_bh;
+	}
+
+	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
+	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
+	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
+	sbi->cluster_size = 1 << sbi->cluster_size_bits;
+	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
+	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
+	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
+		sbi->FAT1_start_sector :
+			sbi->FAT1_start_sector + sbi->num_FAT_sectors;
+	sbi->root_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
+	sbi->data_start_sector = sbi->root_start_sector;
+	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
+	/* because the cluster index starts with 2 */
+	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) + 2;
+
+	sbi->vol_id = le32_to_cpu(p_bpb->bsx.vol_serial);
+	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
+	sbi->dentries_in_root = 0;
+	sbi->dentries_per_clu = 1 <<
+		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
+
+	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
+	sbi->clu_srch_ptr = BASE_CLUSTER;
+	sbi->used_clusters = ~0u;
+
+	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
+		sbi->vol_flag |= VOL_DIRTY;
+		exfat_msg(sb, KERN_WARNING,
+			"Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
+	}
+
+	ret = exfat_create_upcase_table(sb);
+	if (ret) {
+		exfat_msg(sb, KERN_ERR, "failed to load upcase table");
+		goto free_bh;
+	}
+
+	/* allocate-bitmap is only for exFAT */
+	ret = exfat_load_bitmap(sb);
+	if (ret) {
+		exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
+		goto free_upcase_table;
+	}
+
+	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
+	if (ret) {
+		exfat_msg(sb, KERN_ERR, "failed to scan clusters");
+		goto free_alloc_bitmap;
+	}
+
+	return 0;
+
+free_alloc_bitmap:
+	exfat_free_bitmap(sb);
+free_upcase_table:
+	exfat_free_upcase_table(sb);
+free_bh:
+	brelse(bh);
+	return ret;
+}
+
+static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi = sb->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+	struct inode *root_inode;
+	int err;
+
+	if (opts->allow_utime == (unsigned short)-1)
+		opts->allow_utime = ~opts->fs_dmask & 0022;
+
+	if (opts->utf8 && strcmp(opts->iocharset, exfat_iocharset_with_utf8)) {
+		exfat_msg(sb, KERN_WARNING,
+			"utf8 enabled, \"iocharset=%s\" is recommended",
+			exfat_iocharset_with_utf8);
+	}
+
+	if (opts->discard) {
+		struct request_queue *q = bdev_get_queue(sb->s_bdev);
+
+		if (!blk_queue_discard(q))
+			exfat_msg(sb, KERN_WARNING,
+				"mounting with \"discard\" option, but the device does not support discard");
+		opts->discard = 0;
+	}
+
+	sb->s_flags |= SB_NODIRATIME;
+	sb->s_magic = EXFAT_SUPER_MAGIC;
+	sb->s_op = &exfat_sops;
+
+	sb->s_d_op = EXFAT_SB(sb)->options.case_sensitive ?
+			&exfat_dentry_ops : &exfat_ci_dentry_ops;
+
+	err = __exfat_fill_super(sb);
+	if (err) {
+		exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
+		goto check_nls_io;
+	}
+
+	/* set up enough so that it can read an inode */
+	exfat_hash_init(sb);
+
+	sbi->nls_io = load_nls(sbi->options.iocharset);
+	if (!sbi->nls_io) {
+		exfat_msg(sb, KERN_ERR, "IO charset %s not found",
+				sbi->options.iocharset);
+		err = -EINVAL;
+		goto free_table;
+	}
+
+	root_inode = new_inode(sb);
+	if (!root_inode) {
+		exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
+		err = -ENOMEM;
+		goto free_table;
+	}
+
+	root_inode->i_ino = EXFAT_ROOT_INO;
+	inode_set_iversion(root_inode, 1);
+	err = exfat_read_root(root_inode);
+	if (err) {
+		exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
+		goto put_inode;
+	}
+
+	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
+	insert_inode_hash(root_inode);
+
+	sb->s_root = d_make_root(root_inode);
+	if (!sb->s_root) {
+		exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
+		err = -ENOMEM;
+		goto put_inode;
+	}
+
+	return 0;
+
+put_inode:
+	iput(root_inode);
+	sb->s_root = NULL;
+
+free_table:
+	exfat_free_upcase_table(sb);
+	exfat_free_bitmap(sb);
+
+check_nls_io:
+	if (sbi->nls_io)
+		unload_nls(sbi->nls_io);
+	exfat_free_iocharset(sbi);
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+	return err;
+}
+
+static int exfat_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, exfat_fill_super);
+}
+
+static void exfat_free(struct fs_context *fc)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations exfat_context_ops = {
+	.parse_param	= exfat_parse_param,
+	.get_tree	= exfat_get_tree,
+	.free		= exfat_free,
+};
+
+static int exfat_init_fs_context(struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi;
+
+	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	mutex_init(&sbi->s_lock);
+	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
+			DEFAULT_RATELIMIT_BURST);
+
+	sbi->options.fs_uid = current_uid();
+	sbi->options.fs_gid = current_gid();
+	sbi->options.fs_fmask = current->fs->umask;
+	sbi->options.fs_dmask = current->fs->umask;
+	sbi->options.allow_utime = -1;
+	sbi->options.iocharset = exfat_default_iocharset;
+	sbi->options.errors = EXFAT_ERRORS_RO;
+
+	fc->s_fs_info = sbi;
+	fc->ops = &exfat_context_ops;
+	return 0;
+}
+
+static struct file_system_type exfat_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "exfat",
+	.init_fs_context	= exfat_init_fs_context,
+	.parameters		= &exfat_parameters,
+	.kill_sb		= kill_block_super,
+	.fs_flags		= FS_REQUIRES_DEV,
+};
+
+static void exfat_inode_init_once(void *foo)
+{
+	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
+
+	INIT_HLIST_NODE(&ei->i_hash_fat);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init init_exfat_fs(void)
+{
+	int err;
+
+	err = exfat_cache_init();
+	if (err)
+		return err;
+
+	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
+			sizeof(struct exfat_inode_info),
+			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+			exfat_inode_init_once);
+	if (!exfat_inode_cachep) {
+		err = -ENOMEM;
+		goto shutdown_cache;
+	}
+
+	err = register_filesystem(&exfat_fs_type);
+	if (err)
+		goto destroy_cache;
+
+	return 0;
+
+destroy_cache:
+	kmem_cache_destroy(exfat_inode_cachep);
+shutdown_cache:
+	exfat_cache_shutdown();
+	return err;
+}
+
+static void __exit exit_exfat_fs(void)
+{
+	kmem_cache_destroy(exfat_inode_cachep);
+	unregister_filesystem(&exfat_fs_type);
+	exfat_cache_shutdown();
+}
+
+module_init(init_exfat_fs);
+module_exit(exit_exfat_fs);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("exFAT filesystem support");
+MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
-- 
2.17.1

Re: [PATCH v6 02/13] exfat: add super block operations

[Vyacheslav Dubeyko]

On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of superblock operations for exfat.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
>  fs/exfat/super.c | 738
> +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 738 insertions(+)
>  create mode 100644 fs/exfat/super.c
> 
> diff --git a/fs/exfat/super.c b/fs/exfat/super.c
> new file mode 100644
> index 000000000000..f5d5144bd72a
> --- /dev/null
> +++ b/fs/exfat/super.c
> @@ -0,0 +1,738 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/fs_context.h>
> +#include <linux/fs_parser.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/time.h>
> +#include <linux/mount.h>
> +#include <linux/cred.h>
> +#include <linux/statfs.h>
> +#include <linux/seq_file.h>
> +#include <linux/blkdev.h>
> +#include <linux/fs_struct.h>
> +#include <linux/iversion.h>
> +#include <linux/nls.h>
> +#include <linux/buffer_head.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +static char exfat_default_iocharset[] =
> CONFIG_EXFAT_FS_DEFAULT_IOCHARSET;
> +static const char exfat_iocharset_with_utf8[] = "iso8859-1";
> +static struct kmem_cache *exfat_inode_cachep;
> +
> +static void exfat_free_iocharset(struct exfat_sb_info *sbi)
> +{
> +	if (sbi->options.iocharset != exfat_default_iocharset)
> +		kfree(sbi->options.iocharset);
> +}
> +
> +static void exfat_put_super(struct super_block *sb)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	mutex_lock(&sbi->s_lock);
> +	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
> +		sync_blockdev(sb->s_bdev);
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +	exfat_free_upcase_table(sb);
> +	exfat_free_bitmap(sb);
> +	mutex_unlock(&sbi->s_lock);
> +
> +	if (sbi->nls_io) {
> +		unload_nls(sbi->nls_io);
> +		sbi->nls_io = NULL;
> +	}
> +	exfat_free_iocharset(sbi);
> +	sb->s_fs_info = NULL;
> +	kfree(sbi);
> +}
> +
> +static int exfat_sync_fs(struct super_block *sb, int wait)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	int err = 0;
> +
> +	/* If there are some dirty buffers in the bdev inode */
> +	mutex_lock(&sbi->s_lock);
> +	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
> +		sync_blockdev(sb->s_bdev);
> +		if (exfat_set_vol_flags(sb, VOL_CLEAN))
> +			err = -EIO;
> +	}
> +	mutex_unlock(&sbi->s_lock);
> +	return err;
> +}
> +
> +static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
> +{
> +	struct super_block *sb = dentry->d_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
> +
> +	if (sbi->used_clusters == ~0u) {
> +		mutex_lock(&sbi->s_lock);
> +		if (exfat_count_used_clusters(sb, &sbi->used_clusters)) 
> {
> +			mutex_unlock(&sbi->s_lock);
> +			return -EIO;
> +		}
> +		mutex_unlock(&sbi->s_lock);
> +	}
> +
> +	buf->f_type = sb->s_magic;
> +	buf->f_bsize = sbi->cluster_size;
> +	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */


Why does it need to subtract 2? Maybe, it needs to add some comments
here? I believe it's good to introduce some constant instead of
hardcoded value.


> +	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
> +	buf->f_bavail = buf->f_bfree;
> +	buf->f_fsid.val[0] = (unsigned int)id;
> +	buf->f_fsid.val[1] = (unsigned int)(id >> 32);
> +	buf->f_namelen = 260;


Why it was used 260? Maybe 256? If it needs to use some special
constant then it makes sense to explain why it's so. And it will be
good to introduce the special constant again.

> +	return 0;
> +}
> +
> +static int __exfat_set_vol_flags(struct super_block *sb,
> +		unsigned short new_flag, int always_sync)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct pbr64 *bpb;
> +	int sync = 0;

Why sync is not bool type? I believe that bool type could be better
here.

> +
> +	/* flags are not changed */
> +	if (sbi->vol_flag == new_flag)
> +		return 0;
> +
> +	sbi->vol_flag = new_flag;
> +
> +	/* skip updating volume dirty flag,
> +	 * if this volume has been mounted with read-only
> +	 */
> +	if (sb_rdonly(sb))
> +		return 0;
> +
> +	if (!sbi->pbr_bh) {
> +		sbi->pbr_bh = sb_bread(sb, 0);
> +		if (!sbi->pbr_bh) {
> +			exfat_msg(sb, KERN_ERR, "failed to read boot
> sector");
> +			return -ENOMEM;
> +		}
> +	}
> +
> +	bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
> +	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
> +
> +	if (always_sync)
> +		sync = 1;
> +	else if ((new_flag == VOL_DIRTY) && (!buffer_dirty(sbi-
> >pbr_bh)))
> +		sync = 1;
> +	else
> +		sync = 0;
> +
> +	set_buffer_uptodate(sbi->pbr_bh);
> +	mark_buffer_dirty(sbi->pbr_bh);
> +
> +	if (sync)
> +		sync_dirty_buffer(sbi->pbr_bh);
> +	return 0;
> +}
> +
> +int exfat_set_vol_flags(struct super_block *sb, unsigned short
> new_flag)
> +{
> +	return __exfat_set_vol_flags(sb, new_flag, 0);
> +}
> +
> +static int exfat_show_options(struct seq_file *m, struct dentry
> *root)
> +{
> +	struct super_block *sb = root->d_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_mount_options *opts = &sbi->options;
> +
> +	/* Show partition info */
> +	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
> +		seq_printf(m, ",uid=%u",
> +				from_kuid_munged(&init_user_ns, opts-
> >fs_uid));
> +	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
> +		seq_printf(m, ",gid=%u",
> +				from_kgid_munged(&init_user_ns, opts-
> >fs_gid));
> +	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts-
> >fs_dmask);
> +	if (opts->allow_utime)
> +		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
> +	if (sbi->nls_io)
> +		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
> +	if (opts->utf8)
> +		seq_puts(m, ",utf8");
> +	seq_printf(m, ",case_sensitive=%u", opts->case_sensitive);
> +	if (opts->tz_utc)
> +		seq_puts(m, ",tz=UTC");
> +	seq_printf(m, ",bps=%ld", sb->s_blocksize);
> +	if (opts->errors == EXFAT_ERRORS_CONT)
> +		seq_puts(m, ",errors=continue");
> +	else if (opts->errors == EXFAT_ERRORS_PANIC)
> +		seq_puts(m, ",errors=panic");
> +	else
> +		seq_puts(m, ",errors=remount-ro");
> +	if (opts->discard)
> +		seq_puts(m, ",discard");
> +	return 0;
> +}
> +
> +static struct inode *exfat_alloc_inode(struct super_block *sb)
> +{
> +	struct exfat_inode_info *ei;
> +
> +	ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
> +	if (!ei)
> +		return NULL;
> +
> +	init_rwsem(&ei->truncate_lock);
> +	return &ei->vfs_inode;
> +}
> +
> +static void exfat_destroy_inode(struct inode *inode)
> +{
> +	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
> +}
> +
> +static const struct super_operations exfat_sops = {
> +	.alloc_inode   = exfat_alloc_inode,
> +	.destroy_inode = exfat_destroy_inode,
> +	.write_inode   = exfat_write_inode,
> +	.evict_inode  = exfat_evict_inode,
> +	.put_super     = exfat_put_super,
> +	.sync_fs       = exfat_sync_fs,
> +	.statfs        = exfat_statfs,
> +	.show_options  = exfat_show_options,
> +};
> +
> +enum {
> +	Opt_uid,
> +	Opt_gid,
> +	Opt_umask,
> +	Opt_dmask,
> +	Opt_fmask,
> +	Opt_allow_utime,
> +	Opt_charset,
> +	Opt_utf8,
> +	Opt_case_sensitive,
> +	Opt_tz,
> +	Opt_errors,
> +	Opt_discard,
> +};
> +
> +static const struct fs_parameter_spec exfat_param_specs[] = {
> +	fsparam_u32("uid",			Opt_uid),
> +	fsparam_u32("gid",			Opt_gid),
> +	fsparam_u32oct("umask",			Opt_umask),
> +	fsparam_u32oct("dmask",			Opt_dmask),
> +	fsparam_u32oct("fmask",			Opt_fmask),
> +	fsparam_u32oct("allow_utime",		Opt_allow_utime),
> +	fsparam_string("iocharset",		Opt_charset),
> +	fsparam_flag("utf8",			Opt_utf8),
> +	fsparam_flag("case_sensitive",		Opt_case_sensitive),
> +	fsparam_string("tz",			Opt_tz),
> +	fsparam_enum("errors",			Opt_errors),
> +	fsparam_flag("discard",			Opt_discard),
> +	{}
> +};
> +
> +static const struct fs_parameter_enum exfat_param_enums[] = {
> +	{ Opt_errors,	"continue",		EXFAT_ERRORS_CONT },
> +	{ Opt_errors,	"panic",		EXFAT_ERRORS_PANIC },
> +	{ Opt_errors,	"remount-ro",		EXFAT_ERRORS_RO },
> +	{}
> +};
> +
> +static const struct fs_parameter_description exfat_parameters = {
> +	.name		= "exfat",
> +	.specs		= exfat_param_specs,
> +	.enums		= exfat_param_enums,
> +};
> +
> +static int exfat_parse_param(struct fs_context *fc, struct
> fs_parameter *param)
> +{
> +	struct exfat_sb_info *sbi = fc->s_fs_info;
> +	struct exfat_mount_options *opts = &sbi->options;
> +	struct fs_parse_result result;
> +	int opt;
> +
> +	opt = fs_parse(fc, &exfat_parameters, param, &result);
> +	if (opt < 0)
> +		return opt;
> +
> +	switch (opt) {
> +	case Opt_uid:
> +		opts->fs_uid = make_kuid(current_user_ns(),
> result.uint_32);
> +		break;
> +	case Opt_gid:
> +		opts->fs_gid = make_kgid(current_user_ns(),
> result.uint_32);
> +		break;
> +	case Opt_umask:
> +		opts->fs_fmask = result.uint_32;
> +		opts->fs_dmask = result.uint_32;
> +		break;
> +	case Opt_dmask:
> +		opts->fs_dmask = result.uint_32;
> +		break;
> +	case Opt_fmask:
> +		opts->fs_fmask = result.uint_32;
> +		break;
> +	case Opt_allow_utime:
> +		opts->allow_utime = result.uint_32 & 0022;


Maybe it makes sense not to use the hardcoded value here?


> +		break;
> +	case Opt_charset:
> +		exfat_free_iocharset(sbi);
> +		opts->iocharset = kstrdup(param->string, GFP_KERNEL);
> +		if (!opts->iocharset)
> +			return -ENOMEM;
> +		break;
> +	case Opt_case_sensitive:
> +		opts->case_sensitive = 1;
> +		break;
> +	case Opt_utf8:
> +		opts->utf8 = 1;
> +		break;
> +	case Opt_tz:
> +		if (!strcmp(param->string, "UTC"))
> +			opts->tz_utc = 1;
> +		break;
> +	case Opt_errors:
> +		opts->errors = result.uint_32;
> +		break;
> +	case Opt_discard:
> +		opts->discard = 1;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static void exfat_hash_init(struct super_block *sb)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	int i;
> +
> +	spin_lock_init(&sbi->inode_hash_lock);
> +	for (i = 0; i < EXFAT_HASH_SIZE; i++)
> +		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
> +}
> +
> +static int exfat_read_root(struct inode *inode)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	struct exfat_chain cdir;
> +	int num_subdirs, num_clu = 0;
> +
> +	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
> +	ei->entry = -1;
> +	ei->start_clu = sbi->root_dir;
> +	ei->flags = ALLOC_FAT_CHAIN;
> +	ei->type = TYPE_DIR;
> +	ei->version = 0;
> +	ei->rwoffset = 0;
> +	ei->hint_bmap.off = EOF_CLUSTER;
> +	ei->hint_stat.eidx = 0;
> +	ei->hint_stat.clu = sbi->root_dir;
> +	ei->hint_femp.eidx = EXFAT_HINT_NONE;
> +
> +	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
> +	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
> +		return -EIO;
> +	i_size_write(inode, num_clu << sbi->cluster_size_bits);
> +
> +	num_subdirs = exfat_count_dir_entries(sb, &cdir);
> +	if (num_subdirs < 0)
> +		return -EIO;
> +	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
> +
> +	inode->i_uid = sbi->options.fs_uid;
> +	inode->i_gid = sbi->options.fs_gid;
> +	inode_inc_iversion(inode);
> +	inode->i_generation = 0;
> +	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);


Ditto. Maybe it makes sense to use the constants here instead of
hardcoded value?


> +	inode->i_op = &exfat_dir_inode_operations;
> +	inode->i_fop = &exfat_dir_operations;
> +
> +	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size -
> 1))
> +			& ~(sbi->cluster_size - 1)) >> inode-
> >i_blkbits;
> +	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) |
> 0xffffffff;
> +	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
> +	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
> +
> +	exfat_save_attr(inode, ATTR_SUBDIR);
> +	inode->i_mtime = inode->i_atime = inode->i_ctime =
> current_time(inode);
> +	exfat_cache_init_inode(inode);
> +	return 0;
> +}
> +
> +static bool is_exfat(struct pbr *pbr)
> +{
> +	int i = 53;


Why 53? Maybe constant?

> +
> +	do {
> +		if (pbr->bpb.f64.res_zero[i - 1])
> +			break;
> +	} while (--i);
> +	return i ? false : true;
> +}
> +
> +static struct pbr *exfat_read_pbr_with_logical_sector(struct
> super_block *sb,
> +		struct buffer_head **prev_bh)
> +{
> +	struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data;
> +	unsigned short logical_sect = 0;
> +
> +	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
> +
> +	if (!is_power_of_2(logical_sect) ||
> +	    logical_sect < 512 || logical_sect > 4096) {


What about constants here instead of hardcoded values?


> +		exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
> +				logical_sect);
> +		return NULL;
> +	}
> +
> +	if (logical_sect < sb->s_blocksize) {
> +		exfat_msg(sb, KERN_ERR,
> +			"logical sector size too small for device
> (logical sector size = %u)",
> +			logical_sect);
> +		return NULL;
> +	}
> +
> +	if (logical_sect > sb->s_blocksize) {
> +		struct buffer_head *bh = NULL;
> +
> +		__brelse(*prev_bh);
> +		*prev_bh = NULL;
> +
> +		if (!sb_set_blocksize(sb, logical_sect)) {
> +			exfat_msg(sb, KERN_ERR,
> +				"unable to set blocksize %u",
> logical_sect);
> +			return NULL;
> +		}
> +		bh = sb_bread(sb, 0);
> +		if (!bh) {
> +			exfat_msg(sb, KERN_ERR,
> +				"unable to read boot sector (logical
> sector size = %lu)",
> +				sb->s_blocksize);
> +			return NULL;
> +		}
> +
> +		*prev_bh = bh;
> +		p_pbr = (struct pbr *) bh->b_data;
> +	}
> +	return p_pbr;
> +}
> +
> +/* mount the file system volume */
> +static int __exfat_fill_super(struct super_block *sb)
> +{
> +	int ret;
> +	struct pbr *p_pbr;
> +	struct pbr64 *p_bpb;
> +	struct buffer_head *bh;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	/* set block size to read super block */
> +	sb_min_blocksize(sb, 512);

Ditto. What's about constant here?

> +
> +	/* read boot sector */
> +	bh = sb_bread(sb, 0);
> +	if (!bh) {
> +		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
> +		return -EIO;
> +	}
> +
> +	/* PRB is read */
> +	p_pbr = (struct pbr *)bh->b_data;
> +
> +	/* check the validity of PBR */
> +	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
> +		exfat_msg(sb, KERN_ERR, "invalid boot record
> signature");
> +		ret = -EINVAL;
> +		goto free_bh;
> +	}
> +
> +
> +	/* check logical sector size */
> +	p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh);
> +	if (!p_pbr) {
> +		ret = -EIO;
> +		goto free_bh;
> +	}
> +
> +	if (!is_exfat(p_pbr)) {
> +		ret = -EINVAL;
> +		goto free_bh;
> +	}
> +
> +	/* set maximum file size for exFAT */
> +	sb->s_maxbytes = 0x7fffffffffffffffLL;
> +
> +	p_bpb = (struct pbr64 *)p_pbr;
> +	if (!p_bpb->bsx.num_fats) {
> +		exfat_msg(sb, KERN_ERR, "bogus number of FAT
> structure");
> +		ret = -EINVAL;
> +		goto free_bh;
> +	}
> +
> +	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
> +	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
> +	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb-
> >s_blocksize_bits;
> +	sbi->cluster_size = 1 << sbi->cluster_size_bits;
> +	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
> +	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
> +	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
> +		sbi->FAT1_start_sector :
> +			sbi->FAT1_start_sector + sbi->num_FAT_sectors;
> +	sbi->root_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
> +	sbi->data_start_sector = sbi->root_start_sector;
> +	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
> +	/* because the cluster index starts with 2 */
> +	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) + 2;
> +
> +	sbi->vol_id = le32_to_cpu(p_bpb->bsx.vol_serial);
> +	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
> +	sbi->dentries_in_root = 0;
> +	sbi->dentries_per_clu = 1 <<
> +		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
> +
> +	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
> +	sbi->clu_srch_ptr = BASE_CLUSTER;
> +	sbi->used_clusters = ~0u;
> +
> +	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
> +		sbi->vol_flag |= VOL_DIRTY;
> +		exfat_msg(sb, KERN_WARNING,
> +			"Volume was not properly unmounted. Some data
> may be corrupt. Please run fsck.");
> +	}
> +
> +	ret = exfat_create_upcase_table(sb);
> +	if (ret) {
> +		exfat_msg(sb, KERN_ERR, "failed to load upcase table");
> +		goto free_bh;
> +	}
> +
> +	/* allocate-bitmap is only for exFAT */
> +	ret = exfat_load_bitmap(sb);
> +	if (ret) {
> +		exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
> +		goto free_upcase_table;
> +	}
> +
> +	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
> +	if (ret) {
> +		exfat_msg(sb, KERN_ERR, "failed to scan clusters");
> +		goto free_alloc_bitmap;
> +	}
> +
> +	return 0;
> +
> +free_alloc_bitmap:
> +	exfat_free_bitmap(sb);
> +free_upcase_table:
> +	exfat_free_upcase_table(sb);
> +free_bh:
> +	brelse(bh);
> +	return ret;
> +}
> +
> +static int exfat_fill_super(struct super_block *sb, struct
> fs_context *fc)
> +{
> +	struct exfat_sb_info *sbi = sb->s_fs_info;
> +	struct exfat_mount_options *opts = &sbi->options;
> +	struct inode *root_inode;
> +	int err;
> +
> +	if (opts->allow_utime == (unsigned short)-1)
> +		opts->allow_utime = ~opts->fs_dmask & 0022;
> +
> +	if (opts->utf8 && strcmp(opts->iocharset,
> exfat_iocharset_with_utf8)) {
> +		exfat_msg(sb, KERN_WARNING,
> +			"utf8 enabled, \"iocharset=%s\" is
> recommended",
> +			exfat_iocharset_with_utf8);
> +	}
> +
> +	if (opts->discard) {
> +		struct request_queue *q = bdev_get_queue(sb->s_bdev);
> +
> +		if (!blk_queue_discard(q))
> +			exfat_msg(sb, KERN_WARNING,
> +				"mounting with \"discard\" option, but
> the device does not support discard");
> +		opts->discard = 0;
> +	}
> +
> +	sb->s_flags |= SB_NODIRATIME;
> +	sb->s_magic = EXFAT_SUPER_MAGIC;
> +	sb->s_op = &exfat_sops;
> +
> +	sb->s_d_op = EXFAT_SB(sb)->options.case_sensitive ?
> +			&exfat_dentry_ops : &exfat_ci_dentry_ops;
> +
> +	err = __exfat_fill_super(sb);
> +	if (err) {
> +		exfat_msg(sb, KERN_ERR, "failed to recognize exfat
> type");
> +		goto check_nls_io;
> +	}
> +
> +	/* set up enough so that it can read an inode */
> +	exfat_hash_init(sb);
> +
> +	sbi->nls_io = load_nls(sbi->options.iocharset);
> +	if (!sbi->nls_io) {
> +		exfat_msg(sb, KERN_ERR, "IO charset %s not found",
> +				sbi->options.iocharset);
> +		err = -EINVAL;
> +		goto free_table;
> +	}
> +
> +	root_inode = new_inode(sb);
> +	if (!root_inode) {
> +		exfat_msg(sb, KERN_ERR, "failed to allocate root
> inode.");
> +		err = -ENOMEM;
> +		goto free_table;
> +	}
> +
> +	root_inode->i_ino = EXFAT_ROOT_INO;
> +	inode_set_iversion(root_inode, 1);
> +	err = exfat_read_root(root_inode);
> +	if (err) {
> +		exfat_msg(sb, KERN_ERR, "failed to initialize root
> inode.");
> +		goto put_inode;
> +	}
> +
> +	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
> +	insert_inode_hash(root_inode);
> +
> +	sb->s_root = d_make_root(root_inode);
> +	if (!sb->s_root) {
> +		exfat_msg(sb, KERN_ERR, "failed to get the root
> dentry");
> +		err = -ENOMEM;
> +		goto put_inode;
> +	}
> +
> +	return 0;
> +
> +put_inode:
> +	iput(root_inode);
> +	sb->s_root = NULL;
> +
> +free_table:
> +	exfat_free_upcase_table(sb);
> +	exfat_free_bitmap(sb);
> +
> +check_nls_io:
> +	if (sbi->nls_io)
> +		unload_nls(sbi->nls_io);
> +	exfat_free_iocharset(sbi);
> +	sb->s_fs_info = NULL;
> +	kfree(sbi);
> +	return err;
> +}
> +
> +static int exfat_get_tree(struct fs_context *fc)
> +{
> +	return get_tree_bdev(fc, exfat_fill_super);
> +}
> +
> +static void exfat_free(struct fs_context *fc)
> +{
> +	kfree(fc->s_fs_info);
> +}
> +
> +static const struct fs_context_operations exfat_context_ops = {
> +	.parse_param	= exfat_parse_param,
> +	.get_tree	= exfat_get_tree,
> +	.free		= exfat_free,
> +};
> +
> +static int exfat_init_fs_context(struct fs_context *fc)
> +{
> +	struct exfat_sb_info *sbi;
> +
> +	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
> +	if (!sbi)
> +		return -ENOMEM;
> +
> +	mutex_init(&sbi->s_lock);
> +	ratelimit_state_init(&sbi->ratelimit,
> DEFAULT_RATELIMIT_INTERVAL,
> +			DEFAULT_RATELIMIT_BURST);
> +
> +	sbi->options.fs_uid = current_uid();
> +	sbi->options.fs_gid = current_gid();
> +	sbi->options.fs_fmask = current->fs->umask;
> +	sbi->options.fs_dmask = current->fs->umask;
> +	sbi->options.allow_utime = -1;

Why -1? Any special purpose?

Thanks,
Viacheslav Dubeyko.

RE: [PATCH v6 02/13] exfat: add super block operations

[Namjae Jeon]

> > +	sbi->options.fs_gid = current_gid();
> > +	sbi->options.fs_fmask = current->fs->umask;
> > +	sbi->options.fs_dmask = current->fs->umask;
> > +	sbi->options.allow_utime = -1;
> 
> Why -1? Any special purpose?
No, It is just to initialize.
> 
> Thanks,
> Viacheslav Dubeyko.
> 

[PATCH v6 03/13] exfat: add inode operations

[Namjae Jeon]

This adds the implementation of inode operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/inode.c |  693 ++++++++++++++++++++++
 fs/exfat/namei.c | 1459 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 2152 insertions(+)
 create mode 100644 fs/exfat/inode.c
 create mode 100644 fs/exfat/namei.c

diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
new file mode 100644
index 000000000000..e1e20e74c92a
--- /dev/null
+++ b/fs/exfat/inode.c
@@ -0,0 +1,693 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/init.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/time.h>
+#include <linux/writeback.h>
+#include <linux/uio.h>
+#include <linux/random.h>
+#include <linux/iversion.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+/* 2-level option flag */
+enum {
+	BMAP_NOT_CREATE,
+	BMAP_ADD_CLUSTER,
+};
+
+static int __exfat_write_inode(struct inode *inode, int sync)
+{
+	int ret = -EIO;
+	unsigned long long on_disk_size;
+	struct exfat_timestamp tm;
+	struct exfat_dentry *ep, *ep2;
+	struct exfat_entry_set_cache *es = NULL;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	unsigned char is_dir = (ei->type == TYPE_DIR) ? 1 : 0;
+	struct exfat_dir_entry info;
+
+	if (inode->i_ino == EXFAT_ROOT_INO)
+		return 0;
+
+	info.attr = exfat_make_attr(inode);
+	info.size = i_size_read(inode);
+
+	exfat_time_unix2fat(sbi, &inode->i_mtime, &info.modify_timestamp);
+	exfat_time_unix2fat(sbi, &inode->i_ctime, &info.create_timestamp);
+	exfat_time_unix2fat(sbi, &inode->i_atime, &info.access_timestamp);
+
+	/*
+	 * If the indode is already unlinked, there is no need for updating it.
+	 */
+	if (ei->dir.dir == DIR_DELETED)
+		return 0;
+
+	if (is_dir && ei->dir.dir == sbi->root_dir && ei->entry == -1)
+		return 0;
+
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+
+	/* get the directory entry of given file or directory */
+	es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES,
+		&ep);
+	if (!es)
+		return -EIO;
+	ep2 = ep + 1;
+
+	ep->file_attr = cpu_to_le16(info.attr);
+
+	/* set FILE_INFO structure using the acquired struct exfat_dentry */
+	tm.sec  = info.create_timestamp.second;
+	tm.min  = info.create_timestamp.minute;
+	tm.hour = info.create_timestamp.hour;
+	tm.day  = info.create_timestamp.day;
+	tm.mon  = info.create_timestamp.month;
+	tm.year = info.create_timestamp.year;
+	exfat_set_entry_time(ep, &tm, TM_CREATE);
+
+	tm.sec  = info.modify_timestamp.second;
+	tm.min  = info.modify_timestamp.minute;
+	tm.hour = info.modify_timestamp.hour;
+	tm.day  = info.modify_timestamp.day;
+	tm.mon  = info.modify_timestamp.month;
+	tm.year = info.modify_timestamp.year;
+	exfat_set_entry_time(ep, &tm, TM_MODIFY);
+
+	/* File size should be zero if there is no cluster allocated */
+	on_disk_size = info.size;
+
+	if (ei->start_clu == EOF_CLUSTER)
+		on_disk_size = 0;
+
+	ep2->stream_valid_size = cpu_to_le64(on_disk_size);
+	ep2->stream_size = ep2->stream_valid_size;
+
+	ret = exfat_update_dir_chksum_with_entry_set(sb, es, sync);
+	kfree(es);
+	return ret;
+}
+
+int exfat_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	int ret;
+
+	mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
+	ret = __exfat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
+	mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
+
+	return ret;
+}
+
+void exfat_sync_inode(struct inode *inode)
+{
+	lockdep_assert_held(&EXFAT_SB(inode->i_sb)->s_lock);
+	__exfat_write_inode(inode, 1);
+}
+
+/*
+ * Input: inode, (logical) clu_offset, target allocation area
+ * Output: errcode, cluster number
+ * *clu = (~0), if it's unable to allocate a new cluster
+ */
+static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
+		unsigned int *clu, int create)
+{
+	int ret, modified = false;
+	unsigned int last_clu;
+	struct exfat_chain new_clu;
+	struct exfat_dentry *ep;
+	struct exfat_entry_set_cache *es = NULL;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	unsigned int local_clu_offset = clu_offset;
+	unsigned int num_to_be_allocated = 0, num_clusters = 0;
+
+	ei->rwoffset = EXFAT_CLU_TO_B(clu_offset, sbi);
+
+	if (EXFAT_I(inode)->i_size_ondisk > 0)
+		num_clusters =
+			EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->i_size_ondisk,
+			sbi);
+
+	if (clu_offset >= num_clusters)
+		num_to_be_allocated = clu_offset - num_clusters + 1;
+
+	if (!create && (num_to_be_allocated > 0)) {
+		*clu = EOF_CLUSTER;
+		return 0;
+	}
+
+	*clu = last_clu = ei->start_clu;
+
+	if (ei->flags == ALLOC_NO_FAT_CHAIN) {
+		if (clu_offset > 0 && *clu != EOF_CLUSTER) {
+			last_clu += clu_offset - 1;
+
+			if (clu_offset == num_clusters)
+				*clu = EOF_CLUSTER;
+			else
+				*clu += clu_offset;
+		}
+	} else if (ei->type == TYPE_FILE) {
+		unsigned int fclus = 0;
+		int err = exfat_get_cluster(inode, clu_offset,
+				&fclus, clu, &last_clu, 1);
+		if (err)
+			return -EIO;
+
+		clu_offset -= fclus;
+	} else {
+		/* hint information */
+		if (clu_offset > 0 && ei->hint_bmap.off != EOF_CLUSTER &&
+		    ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
+			clu_offset -= ei->hint_bmap.off;
+			/* hint_bmap.clu should be valid */
+			WARN_ON(ei->hint_bmap.clu < 2);
+			*clu = ei->hint_bmap.clu;
+		}
+
+		while (clu_offset > 0 && *clu != EOF_CLUSTER) {
+			last_clu = *clu;
+			if (exfat_get_next_cluster(sb, clu))
+				return -EIO;
+			clu_offset--;
+		}
+	}
+
+	if (*clu == EOF_CLUSTER) {
+		exfat_set_vol_flags(sb, VOL_DIRTY);
+
+		new_clu.dir = (last_clu == EOF_CLUSTER) ?
+				EOF_CLUSTER : last_clu + 1;
+		new_clu.size = 0;
+		new_clu.flags = ei->flags;
+
+		/* allocate a cluster */
+		if (num_to_be_allocated < 1) {
+			/* Broken FAT (i_sze > allocated FAT) */
+			exfat_fs_error(sb, "broken FAT chain.");
+			return -EIO;
+		}
+
+		ret = exfat_alloc_cluster(inode, num_to_be_allocated, &new_clu);
+		if (ret)
+			return ret;
+
+		if (new_clu.dir == EOF_CLUSTER || new_clu.dir == FREE_CLUSTER) {
+			exfat_fs_error(sb,
+				"bogus cluster new allocated (last_clu : %u, new_clu : %u)",
+				last_clu, new_clu.dir);
+			return -EIO;
+		}
+
+		/* append to the FAT chain */
+		if (last_clu == EOF_CLUSTER) {
+			if (new_clu.flags == ALLOC_FAT_CHAIN)
+				ei->flags = ALLOC_FAT_CHAIN;
+			ei->start_clu = new_clu.dir;
+			modified = true;
+		} else {
+			if (new_clu.flags != ei->flags) {
+				/* no-fat-chain bit is disabled,
+				 * so fat-chain should be synced with
+				 * alloc-bitmap
+				 */
+				exfat_chain_cont_cluster(sb, ei->start_clu,
+					num_clusters);
+				ei->flags = ALLOC_FAT_CHAIN;
+				modified = true;
+			}
+			if (new_clu.flags == ALLOC_FAT_CHAIN)
+				if (exfat_ent_set(sb, last_clu, new_clu.dir))
+					return -EIO;
+		}
+
+		num_clusters += num_to_be_allocated;
+		*clu = new_clu.dir;
+
+		if (ei->dir.dir != DIR_DELETED) {
+			es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
+				ES_ALL_ENTRIES, &ep);
+			if (!es)
+				return -EIO;
+			/* get stream entry */
+			ep++;
+
+			/* update directory entry */
+			if (modified) {
+				if (ep->stream_flags != ei->flags)
+					ep->stream_flags = ei->flags;
+
+				if (le32_to_cpu(ep->stream_start_clu) !=
+						ei->start_clu)
+					ep->stream_start_clu =
+						cpu_to_le32(ei->start_clu);
+
+				ep->stream_valid_size =
+					cpu_to_le64(i_size_read(inode));
+				ep->stream_size = ep->stream_valid_size;
+			}
+
+			if (exfat_update_dir_chksum_with_entry_set(sb, es,
+			    inode_needs_sync(inode)))
+				return -EIO;
+			kfree(es);
+
+		} /* end of if != DIR_DELETED */
+
+		inode->i_blocks +=
+			num_to_be_allocated << sbi->sect_per_clus_bits;
+
+		/*
+		 * Move *clu pointer along FAT chains (hole care) because the
+		 * caller of this function expect *clu to be the last cluster.
+		 * This only works when num_to_be_allocated >= 2,
+		 * *clu = (the first cluster of the allocated chain) =>
+		 * (the last cluster of ...)
+		 */
+		if (ei->flags == ALLOC_NO_FAT_CHAIN) {
+			*clu += num_to_be_allocated - 1;
+		} else {
+			while (num_to_be_allocated > 1) {
+				if (exfat_get_next_cluster(sb, clu))
+					return -EIO;
+				num_to_be_allocated--;
+			}
+		}
+
+	}
+
+	/* hint information */
+	ei->hint_bmap.off = local_clu_offset;
+	ei->hint_bmap.clu = *clu;
+
+	return 0;
+}
+
+static int exfat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
+		unsigned long *mapped_blocks, int *create)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	sector_t last_block;
+	unsigned int cluster, clu_offset, sec_offset;
+	int err = 0;
+
+	*phys = 0;
+	*mapped_blocks = 0;
+
+	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
+	if (sector >= last_block && *create == BMAP_NOT_CREATE)
+		return 0;
+
+	/* Is this block already allocated? */
+	clu_offset = sector >> sbi->sect_per_clus_bits;  /* cluster offset */
+
+	err = exfat_map_cluster(inode, clu_offset, &cluster,
+		*create & BMAP_ADD_CLUSTER);
+	if (err) {
+		if (err != -ENOSPC)
+			return -EIO;
+		return err;
+	}
+
+	if (cluster != EOF_CLUSTER) {
+		/* sector offset in cluster */
+		sec_offset = sector & (sbi->sect_per_clus - 1);
+
+		*phys = exfat_cluster_to_sector(sbi, cluster) + sec_offset;
+		*mapped_blocks = sbi->sect_per_clus - sec_offset;
+	}
+
+	if (sector < last_block)
+		*create = BMAP_NOT_CREATE;
+	return 0;
+}
+
+static int exfat_get_block(struct inode *inode, sector_t iblock,
+		struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int err = 0;
+	unsigned long mapped_blocks;
+	sector_t phys;
+	loff_t pos;
+	int bmap_create = create ? BMAP_ADD_CLUSTER : BMAP_NOT_CREATE;
+
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	err = exfat_bmap(inode, iblock, &phys, &mapped_blocks, &bmap_create);
+	if (err) {
+		if (err != -ENOSPC)
+			exfat_fs_error_ratelimit(sb,
+				"failed to bmap (inode : %p iblock : %llu, err : %d)",
+				inode, (unsigned long long)iblock, err);
+		goto unlock_ret;
+	}
+
+	if (phys) {
+		max_blocks = min(mapped_blocks, max_blocks);
+
+		/* Treat newly added block / cluster */
+		if (bmap_create || buffer_delay(bh_result)) {
+			/* Update i_size_ondisk */
+			pos = EXFAT_BLK_TO_B((iblock + 1), sb);
+			if (EXFAT_I(inode)->i_size_ondisk < pos)
+				EXFAT_I(inode)->i_size_ondisk = pos;
+
+			if (bmap_create) {
+				if (buffer_delay(bh_result) &&
+				    pos > EXFAT_I(inode)->i_size_aligned) {
+					exfat_fs_error(sb,
+						"requested for bmap out of range(pos : (%llu) > i_size_aligned(%llu)\n",
+						pos,
+						EXFAT_I(inode)->i_size_aligned);
+					err = -EIO;
+					goto unlock_ret;
+				}
+				set_buffer_new(bh_result);
+
+				/*
+				 * adjust i_size_aligned if i_size_ondisk is
+				 * bigger than it. (i.e. non-DA)
+				 */
+				if (EXFAT_I(inode)->i_size_ondisk >
+				    EXFAT_I(inode)->i_size_aligned) {
+					EXFAT_I(inode)->i_size_aligned =
+						EXFAT_I(inode)->i_size_ondisk;
+				}
+			}
+
+			if (buffer_delay(bh_result))
+				clear_buffer_delay(bh_result);
+		}
+		map_bh(bh_result, sb, phys);
+	}
+
+	bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb);
+unlock_ret:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	return err;
+}
+
+static int exfat_readpage(struct file *file, struct page *page)
+{
+	return mpage_readpage(page, exfat_get_block);
+}
+
+static int exfat_readpages(struct file *file, struct address_space *mapping,
+		struct list_head *pages, unsigned int nr_pages)
+{
+	return mpage_readpages(mapping, pages, nr_pages, exfat_get_block);
+}
+
+static int exfat_writepage(struct page *page, struct writeback_control *wbc)
+{
+	return block_write_full_page(page, exfat_get_block, wbc);
+}
+
+static int exfat_writepages(struct address_space *mapping,
+		struct writeback_control *wbc)
+{
+	return mpage_writepages(mapping, wbc, exfat_get_block);
+}
+
+static void exfat_write_failed(struct address_space *mapping, loff_t to)
+{
+	struct inode *inode = mapping->host;
+
+	if (to > i_size_read(inode)) {
+		truncate_pagecache(inode, i_size_read(inode));
+		exfat_truncate(inode, EXFAT_I(inode)->i_size_aligned);
+	}
+}
+
+static int exfat_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned int len, unsigned int flags,
+		struct page **pagep, void **fsdata)
+{
+	int ret;
+
+	*pagep = NULL;
+	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+			       exfat_get_block,
+			       &EXFAT_I(mapping->host)->i_size_ondisk);
+
+	if (ret < 0)
+		exfat_write_failed(mapping, pos+len);
+
+	return ret;
+}
+
+static int exfat_write_end(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned int len, unsigned int copied,
+		struct page *pagep, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	int err;
+
+	err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
+
+	if (EXFAT_I(inode)->i_size_aligned < i_size_read(inode)) {
+		exfat_fs_error(inode->i_sb,
+			"invalid size(size(%llu) > aligned(%llu)\n",
+			i_size_read(inode), EXFAT_I(inode)->i_size_aligned);
+		return -EIO;
+	}
+
+	if (err < len)
+		exfat_write_failed(mapping, pos+len);
+
+	if (!(err < 0) && !(ei->attr & ATTR_ARCHIVE)) {
+		inode->i_mtime = inode->i_ctime = current_time(inode);
+		ei->attr |= ATTR_ARCHIVE;
+		mark_inode_dirty(inode);
+	}
+
+	return err;
+}
+
+static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct address_space *mapping = iocb->ki_filp->f_mapping;
+	struct inode *inode = mapping->host;
+	loff_t size = iocb->ki_pos + iov_iter_count(iter);
+	int rw = iov_iter_rw(iter);
+	ssize_t ret;
+
+	if (rw == WRITE) {
+		/*
+		 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
+		 * so we need to update the ->i_size_aligned to block boundary.
+		 *
+		 * But we must fill the remaining area or hole by nul for
+		 * updating ->i_size_aligned
+		 *
+		 * Return 0, and fallback to normal buffered write.
+		 */
+		if (EXFAT_I(inode)->i_size_aligned < size)
+			return 0;
+	}
+
+	/*
+	 * Need to use the DIO_LOCKING for avoiding the race
+	 * condition of exfat_get_block() and ->truncate().
+	 */
+	ret = blockdev_direct_IO(iocb, inode, iter, exfat_get_block);
+	if (ret < 0 && (rw & WRITE))
+		exfat_write_failed(mapping, size);
+	return ret;
+}
+
+static sector_t exfat_aop_bmap(struct address_space *mapping, sector_t block)
+{
+	sector_t blocknr;
+
+	/* exfat_get_cluster() assumes the requested blocknr isn't truncated. */
+	down_read(&EXFAT_I(mapping->host)->truncate_lock);
+	blocknr = generic_block_bmap(mapping, block, exfat_get_block);
+	up_read(&EXFAT_I(mapping->host)->truncate_lock);
+	return blocknr;
+}
+
+static const struct address_space_operations exfat_aops = {
+	.readpage	= exfat_readpage,
+	.readpages	= exfat_readpages,
+	.writepage	= exfat_writepage,
+	.writepages	= exfat_writepages,
+	.write_begin	= exfat_write_begin,
+	.write_end	= exfat_write_end,
+	.direct_IO	= exfat_direct_IO,
+	.bmap		= exfat_aop_bmap
+};
+
+static inline unsigned long exfat_hash(loff_t i_pos)
+{
+	return hash_32(i_pos, EXFAT_HASH_BITS);
+}
+
+void exfat_hash_inode(struct inode *inode, loff_t i_pos)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
+	struct hlist_head *head = sbi->inode_hashtable + exfat_hash(i_pos);
+
+	spin_lock(&sbi->inode_hash_lock);
+	EXFAT_I(inode)->i_pos = i_pos;
+	hlist_add_head(&EXFAT_I(inode)->i_hash_fat, head);
+	spin_unlock(&sbi->inode_hash_lock);
+}
+
+void exfat_unhash_inode(struct inode *inode)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
+
+	spin_lock(&sbi->inode_hash_lock);
+	hlist_del_init(&EXFAT_I(inode)->i_hash_fat);
+	EXFAT_I(inode)->i_pos = 0;
+	spin_unlock(&sbi->inode_hash_lock);
+}
+
+struct inode *exfat_iget(struct super_block *sb, loff_t i_pos)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *info;
+	struct hlist_head *head = sbi->inode_hashtable + exfat_hash(i_pos);
+	struct inode *inode = NULL;
+
+	spin_lock(&sbi->inode_hash_lock);
+	hlist_for_each_entry(info, head, i_hash_fat) {
+		WARN_ON(info->vfs_inode.i_sb != sb);
+
+		if (i_pos != info->i_pos)
+			continue;
+		inode = igrab(&info->vfs_inode);
+		if (inode)
+			break;
+	}
+	spin_unlock(&sbi->inode_hash_lock);
+	return inode;
+}
+
+/* doesn't deal with root inode */
+static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	loff_t size = info->size;
+
+	memcpy(&ei->dir, &info->dir, sizeof(struct exfat_chain));
+	ei->entry = info->entry;
+	ei->attr = info->attr;
+	ei->start_clu = info->start_clu;
+	ei->flags = info->flags;
+	ei->type = info->type;
+
+	ei->version = 0;
+	ei->hint_stat.eidx = 0;
+	ei->hint_stat.clu = info->start_clu;
+	ei->hint_femp.eidx = EXFAT_HINT_NONE;
+	ei->rwoffset = 0;
+	ei->hint_bmap.off = EOF_CLUSTER;
+	ei->i_pos = 0;
+
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode_inc_iversion(inode);
+	inode->i_generation = prandom_u32();
+
+	if (info->attr & ATTR_SUBDIR) { /* directory */
+		inode->i_generation &= ~1;
+		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
+		inode->i_op = &exfat_dir_inode_operations;
+		inode->i_fop = &exfat_dir_operations;
+		set_nlink(inode, info->num_subdirs);
+	} else { /* regular file */
+		inode->i_generation |= 1;
+		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
+		inode->i_op = &exfat_file_inode_operations;
+		inode->i_fop = &exfat_file_operations;
+		inode->i_mapping->a_ops = &exfat_aops;
+		inode->i_mapping->nrpages = 0;
+	}
+
+	i_size_write(inode, size);
+
+	/* ondisk and aligned size should be aligned with block size */
+	if (size & (inode->i_sb->s_blocksize - 1)) {
+		size |= (inode->i_sb->s_blocksize - 1);
+		size++;
+	}
+
+	ei->i_size_aligned = size;
+	ei->i_size_ondisk = size;
+
+	exfat_save_attr(inode, info->attr);
+
+	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) &
+		~(sbi->cluster_size - 1)) >> inode->i_blkbits;
+
+	exfat_time_fat2unix(sbi, &inode->i_mtime, &info->modify_timestamp);
+	exfat_time_fat2unix(sbi, &inode->i_ctime, &info->create_timestamp);
+	exfat_time_fat2unix(sbi, &inode->i_atime, &info->access_timestamp);
+
+	exfat_cache_init_inode(inode);
+
+	return 0;
+}
+
+struct inode *exfat_build_inode(struct super_block *sb,
+		struct exfat_dir_entry *info, loff_t i_pos)
+{
+	struct inode *inode;
+	int err;
+
+	inode = exfat_iget(sb, i_pos);
+	if (inode)
+		goto out;
+	inode = new_inode(sb);
+	if (!inode) {
+		inode = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+	inode->i_ino = iunique(sb, EXFAT_ROOT_INO);
+	inode_set_iversion(inode, 1);
+	err = exfat_fill_inode(inode, info);
+	if (err) {
+		iput(inode);
+		inode = ERR_PTR(err);
+		goto out;
+	}
+	exfat_hash_inode(inode, i_pos);
+	insert_inode_hash(inode);
+out:
+	return inode;
+}
+
+void exfat_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages(&inode->i_data, 0);
+
+	if (!inode->i_nlink) {
+		i_size_write(inode, 0);
+		mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
+		__exfat_truncate(inode, 0);
+		mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
+	}
+
+	invalidate_inode_buffers(inode);
+	clear_inode(inode);
+	exfat_cache_inval_inode(inode);
+	exfat_unhash_inode(inode);
+}
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
new file mode 100644
index 000000000000..120a50fc494a
--- /dev/null
+++ b/fs/exfat/namei.c
@@ -0,0 +1,1459 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/iversion.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+#include <linux/nls.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static inline unsigned long exfat_d_version(struct dentry *dentry)
+{
+	return (unsigned long) dentry->d_fsdata;
+}
+
+static inline void exfat_d_version_set(struct dentry *dentry,
+		unsigned long version)
+{
+	dentry->d_fsdata = (void *) version;
+}
+
+/*
+ * If new entry was created in the parent, it could create the 8.3
+ * alias (the shortname of logname).  So, the parent may have the
+ * negative-dentry which matches the created 8.3 alias.
+ *
+ * If it happened, the negative dentry isn't actually negative
+ * anymore.  So, drop it.
+ */
+static int __exfat_revalidate_common(struct dentry *dentry)
+{
+	int ret = 1;
+
+	spin_lock(&dentry->d_lock);
+	if (!inode_eq_iversion(d_inode(dentry->d_parent),
+			exfat_d_version(dentry)))
+		ret = 0;
+	spin_unlock(&dentry->d_lock);
+	return ret;
+}
+
+static int __exfat_revalidate(struct dentry *dentry)
+{
+	/* This is not negative dentry. Always valid. */
+	if (d_really_is_positive(dentry))
+		return 1;
+	return __exfat_revalidate_common(dentry);
+}
+
+static int __exfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
+{
+	/*
+	 * This is not negative dentry. Always valid.
+	 *
+	 * Note, rename() to existing directory entry will have ->d_inode,
+	 * and will use existing name which isn't specified name by user.
+	 *
+	 * We may be able to drop this positive dentry here. But dropping
+	 * positive dentry isn't good idea. So it's unsupported like
+	 * rename("filename", "FILENAME") for now.
+	 */
+	if (d_really_is_positive(dentry))
+		return 1;
+	/*
+	 * Drop the negative dentry, in order to make sure to use the
+	 * case sensitive name which is specified by user if this is
+	 * for creation.
+	 */
+	if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
+		return 0;
+	return __exfat_revalidate_common(dentry);
+}
+
+
+/* returns the length of a struct qstr, ignoring trailing dots */
+static unsigned int __exfat_striptail_len(unsigned int len, const char *name)
+{
+	while (len && name[len - 1] == '.')
+		len--;
+	return len;
+}
+
+static unsigned int exfat_striptail_len(const struct qstr *qstr)
+{
+	return __exfat_striptail_len(qstr->len, qstr->name);
+}
+
+static inline unsigned int __exfat_full_name_hash(const struct dentry *dentry,
+		const char *name, unsigned int len)
+{
+	return full_name_hash(dentry, name, len);
+}
+
+static inline unsigned long __exfat_init_name_hash(const struct dentry *dentry)
+{
+	return init_name_hash(dentry);
+}
+
+/*
+ * Compute the hash for the exfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The exfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int exfat_d_hash(const struct dentry *dentry, struct qstr *qstr)
+{
+	unsigned int len = exfat_striptail_len(qstr);
+
+	qstr->hash = __exfat_full_name_hash(dentry, qstr->name, len);
+	return 0;
+}
+
+/*
+ * Compute the hash for the exfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The exfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int exfat_d_hashi(const struct dentry *dentry, struct qstr *qstr)
+{
+	struct nls_table *t = EXFAT_SB(dentry->d_sb)->nls_io;
+	const unsigned char *name;
+	unsigned int len;
+	unsigned long hash;
+
+	name = qstr->name;
+	len = exfat_striptail_len(qstr);
+
+	hash = __exfat_init_name_hash(dentry);
+	while (len--)
+		hash = partial_name_hash(nls_tolower(t, *name++), hash);
+	qstr->hash = end_name_hash(hash);
+
+	return 0;
+}
+
+/*
+ * Case sensitive compare of two exfat names.
+ */
+static int exfat_cmp(const struct dentry *dentry, unsigned int len,
+		const char *str, const struct qstr *name)
+{
+	unsigned int alen, blen;
+
+	/* A filename cannot end in '.' or we treat it like it has none */
+	alen = exfat_striptail_len(name);
+	blen = __exfat_striptail_len(len, str);
+	if (alen == blen) {
+		if (strncmp(name->name, str, alen) == 0)
+			return 0;
+	}
+	return 1;
+}
+
+/*
+ * Case insensitive compare of two exfat names.
+ */
+static int exfat_cmpi(const struct dentry *dentry, unsigned int len,
+		const char *str, const struct qstr *name)
+{
+	struct nls_table *t = EXFAT_SB(dentry->d_sb)->nls_io;
+	unsigned int alen, blen;
+
+	/* A filename cannot end in '.' or we treat it like it has none */
+	alen = exfat_striptail_len(name);
+	blen = __exfat_striptail_len(len, str);
+	if (alen == blen) {
+		if (nls_strnicmp(t, name->name, str, alen) == 0)
+			return 0;
+	}
+	return 1;
+}
+
+static int exfat_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	return __exfat_revalidate(dentry);
+}
+
+static int exfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
+{
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	return __exfat_revalidate_ci(dentry, flags);
+}
+
+const struct dentry_operations exfat_dentry_ops = {
+	.d_revalidate	= exfat_revalidate,
+	.d_hash		= exfat_d_hash,
+	.d_compare	= exfat_cmp,
+};
+
+const struct dentry_operations exfat_ci_dentry_ops = {
+	.d_revalidate	= exfat_revalidate_ci,
+	.d_hash		= exfat_d_hashi,
+	.d_compare	= exfat_cmpi,
+};
+
+/* used only in search empty_slot() */
+#define CNT_UNUSED_NOHIT        (-1)
+#define CNT_UNUSED_HIT          (-2)
+/* search EMPTY CONTINUOUS "num_entries" entries */
+static int exfat_search_empty_slot(struct super_block *sb,
+		struct exfat_hint_femp *hint_femp, struct exfat_chain *p_dir,
+		int num_entries)
+{
+	int i, dentry, num_empty = 0;
+	int dentries_per_clu;
+	unsigned int type;
+	struct exfat_chain clu;
+	struct exfat_dentry *ep;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+
+	dentries_per_clu = sbi->dentries_per_clu;
+
+	if (hint_femp->eidx != EXFAT_HINT_NONE) {
+		dentry = hint_femp->eidx;
+		if (num_entries <= hint_femp->count) {
+			hint_femp->eidx = EXFAT_HINT_NONE;
+			return dentry;
+		}
+
+		exfat_chain_dup(&clu, &hint_femp->cur);
+	} else {
+		exfat_chain_dup(&clu, p_dir);
+		dentry = 0;
+	}
+
+	while (clu.dir != EOF_CLUSTER) {
+		i = dentry & (dentries_per_clu - 1);
+
+		for (; i < dentries_per_clu; i++, dentry++) {
+			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
+			if (!ep)
+				return -EIO;
+			type = exfat_get_entry_type(ep);
+			brelse(bh);
+
+			if (type == TYPE_UNUSED || type == TYPE_DELETED) {
+				num_empty++;
+				if (hint_femp->eidx == EXFAT_HINT_NONE) {
+					hint_femp->eidx = dentry;
+					hint_femp->count = CNT_UNUSED_NOHIT;
+					exfat_chain_set(&hint_femp->cur,
+						clu.dir, clu.size, clu.flags);
+				}
+
+				if (type == TYPE_UNUSED &&
+				    hint_femp->count != CNT_UNUSED_HIT)
+					hint_femp->count = CNT_UNUSED_HIT;
+			} else {
+				if (hint_femp->eidx != EXFAT_HINT_NONE &&
+				    hint_femp->count == CNT_UNUSED_HIT) {
+					/* unused empty group means
+					 * an empty group which includes
+					 * unused dentry
+					 */
+					exfat_fs_error(sb,
+						"found bogus dentry(%d) beyond unused empty group(%d) (start_clu : %u, cur_clu : %u)",
+						dentry, hint_femp->eidx,
+						p_dir->dir, clu.dir);
+					return -EIO;
+				}
+
+				num_empty = 0;
+				hint_femp->eidx = EXFAT_HINT_NONE;
+			}
+
+			if (num_empty >= num_entries) {
+				/* found and invalidate hint_femp */
+				hint_femp->eidx = EXFAT_HINT_NONE;
+				return (dentry - (num_entries - 1));
+			}
+		}
+
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			if (--clu.size > 0)
+				clu.dir++;
+			else
+				clu.dir = EOF_CLUSTER;
+		} else {
+			if (exfat_get_next_cluster(sb, &clu.dir))
+				return -EIO;
+		}
+	}
+
+	return -ENOSPC;
+}
+
+static int exfat_check_max_dentries(struct inode *inode)
+{
+	if (EXFAT_B_TO_DEN(i_size_read(inode)) >= MAX_EXFAT_DENTRIES) {
+		/*
+		 * exFAT spec allows a dir to grow upto 8388608(256MB)
+		 * dentries
+		 */
+		return -ENOSPC;
+	}
+	return 0;
+}
+
+/* find empty directory entry.
+ * if there isn't any empty slot, expand cluster chain.
+ */
+int exfat_find_empty_entry(struct inode *inode, struct exfat_chain *p_dir,
+		int num_entries)
+{
+	int dentry;
+	unsigned int ret, last_clu;
+	sector_t sector;
+	loff_t size = 0;
+	struct exfat_chain clu;
+	struct exfat_dentry *ep = NULL;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_hint_femp hint_femp;
+
+	hint_femp.eidx = EXFAT_HINT_NONE;
+
+	if (ei->hint_femp.eidx != EXFAT_HINT_NONE) {
+		memcpy(&hint_femp, &ei->hint_femp,
+				sizeof(struct exfat_hint_femp));
+		ei->hint_femp.eidx = EXFAT_HINT_NONE;
+	}
+
+	while ((dentry = exfat_search_empty_slot(sb, &hint_femp, p_dir,
+					num_entries)) < 0) {
+		if (dentry == -EIO)
+			break;
+
+		if (exfat_check_max_dentries(inode))
+			return -ENOSPC;
+
+		/* we trust p_dir->size regardless of FAT type */
+		if (exfat_find_last_cluster(sb, p_dir, &last_clu))
+			return -EIO;
+
+		/*
+		 * Allocate new cluster to this directory
+		 */
+		exfat_chain_set(&clu, last_clu + 1, 0, p_dir->flags);
+
+		/* allocate a cluster */
+		ret = exfat_alloc_cluster(inode, 1, &clu);
+		if (ret)
+			return ret;
+
+		if (exfat_zeroed_cluster(inode, clu.dir))
+			return -EIO;
+
+		/* append to the FAT chain */
+		if (clu.flags != p_dir->flags) {
+			/* no-fat-chain bit is disabled,
+			 * so fat-chain should be synced with alloc-bitmap
+			 */
+			exfat_chain_cont_cluster(sb, p_dir->dir, p_dir->size);
+			p_dir->flags = ALLOC_FAT_CHAIN;
+			hint_femp.cur.flags = ALLOC_FAT_CHAIN;
+		}
+
+		if (clu.flags == ALLOC_FAT_CHAIN)
+			if (exfat_ent_set(sb, last_clu, clu.dir))
+				return -EIO;
+
+		if (hint_femp.eidx == EXFAT_HINT_NONE) {
+			/* the special case that new dentry
+			 * should be allocated from the start of new cluster
+			 */
+			hint_femp.eidx = EXFAT_B_TO_DEN_IDX(p_dir->size, sbi);
+			hint_femp.count = sbi->dentries_per_clu;
+
+			exfat_chain_set(&hint_femp.cur, clu.dir, 0, clu.flags);
+		}
+		hint_femp.cur.size++;
+		p_dir->size++;
+		size = EXFAT_CLU_TO_B(p_dir->size, sbi);
+
+		/* update the directory entry */
+		if (p_dir->dir != sbi->root_dir) {
+			struct buffer_head *bh;
+
+			ep = exfat_get_dentry(sb,
+				&(ei->dir), ei->entry + 1, &bh, &sector);
+			if (!ep)
+				return -EIO;
+
+			ep->stream_valid_size = cpu_to_le64(size);
+			ep->stream_size = ep->stream_valid_size;
+			ep->stream_flags = p_dir->flags;
+			exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
+			brelse(bh);
+			if (update_dir_chksum(inode, &(ei->dir), ei->entry))
+				return -EIO;
+		}
+
+		/* directory inode should be updated in here */
+		i_size_write(inode, size);
+		EXFAT_I(inode)->i_size_ondisk += sbi->cluster_size;
+		EXFAT_I(inode)->i_size_aligned += sbi->cluster_size;
+		EXFAT_I(inode)->flags = p_dir->flags;
+		inode->i_blocks += 1 << sbi->sect_per_clus_bits;
+	}
+
+	return dentry;
+}
+
+/*
+ * Name Resolution Functions :
+ * Zero if it was successful; otherwise nonzero.
+ */
+static int __exfat_resolve_path(struct inode *inode, const unsigned char *path,
+		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
+		int lookup)
+{
+	int namelen;
+	int lossy = NLS_NAME_NO_LOSSY;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+
+	/* DOT and DOTDOT are handled by VFS layer */
+
+	/* strip all trailing spaces */
+	/* DO NOTHING : Is needed? */
+
+	/* strip all trailing periods */
+	namelen = __exfat_striptail_len(strlen(path), path);
+	if (!namelen)
+		return -ENOENT;
+
+	/* the limitation of linux? */
+	if (strlen(path) > (MAX_NAME_LENGTH * MAX_CHARSET_SIZE))
+		return -ENAMETOOLONG;
+
+	/*
+	 * strip all leading spaces :
+	 * "MS windows 7" supports leading spaces.
+	 * So we should skip this preprocessing for compatibility.
+	 */
+
+	/* file name conversion :
+	 * If lookup case, we allow bad-name for compatibility.
+	 */
+	namelen = exfat_nls_vfsname_to_uni16s(sb, path, namelen, p_uniname,
+			&lossy);
+	if (namelen < 0)
+		return namelen; /* return error value */
+
+	if ((lossy && !lookup) || !namelen)
+		return -EINVAL;
+
+	exfat_chain_set(p_dir, ei->start_clu,
+		EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
+
+	return 0;
+}
+
+static inline int exfat_resolve_path(struct inode *inode,
+		const unsigned char *path, struct exfat_chain *dir,
+		struct exfat_uni_name *uni)
+{
+	return __exfat_resolve_path(inode, path, dir, uni, 0);
+}
+
+static inline int exfat_resolve_path_for_lookup(struct inode *inode,
+		const unsigned char *path, struct exfat_chain *dir,
+		struct exfat_uni_name *uni)
+{
+	return __exfat_resolve_path(inode, path, dir, uni, 1);
+}
+
+static inline loff_t exfat_make_i_pos(struct exfat_dir_entry *info)
+{
+	return ((loff_t) info->dir.dir << 32) | (info->entry & 0xffffffff);
+}
+
+static int exfat_add_entry(struct inode *inode, const char *path,
+		struct exfat_chain *p_dir, unsigned int type,
+		struct exfat_dir_entry *info)
+{
+	int ret, dentry, num_entries;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_uni_name uniname;
+	struct exfat_chain clu;
+	int clu_size = 0;
+	unsigned int start_clu = FREE_CLUSTER;
+
+	ret = exfat_resolve_path(inode, path, p_dir, &uniname);
+	if (ret)
+		goto out;
+
+	num_entries = exfat_get_num_entries(&uniname);
+	if (num_entries < 0) {
+		ret = num_entries;
+		goto out;
+	}
+
+	/* exfat_find_empty_entry must be called before alloc_cluster() */
+	dentry = exfat_find_empty_entry(inode, p_dir, num_entries);
+	if (dentry < 0) {
+		ret = dentry; /* -EIO or -ENOSPC */
+		goto out;
+	}
+
+	if (type == TYPE_DIR) {
+		ret = exfat_alloc_new_dir(inode, &clu);
+		if (ret)
+			goto out;
+		start_clu = clu.dir;
+		clu_size = sbi->cluster_size;
+	}
+
+	/* update the directory entry */
+	/* fill the dos name directory entry information of the created file.
+	 * the first cluster is not determined yet. (0)
+	 */
+	ret = exfat_init_dir_entry(inode, p_dir, dentry, type,
+		start_clu, clu_size);
+	if (ret)
+		goto out;
+
+	ret = exfat_init_ext_entry(inode, p_dir, dentry, num_entries, &uniname);
+	if (ret)
+		goto out;
+
+	memcpy(&info->dir, p_dir, sizeof(struct exfat_chain));
+	info->entry = dentry;
+	info->flags = ALLOC_NO_FAT_CHAIN;
+	info->type = type;
+
+	if (type == TYPE_FILE) {
+		info->attr = ATTR_ARCHIVE;
+		info->start_clu = EOF_CLUSTER;
+		info->size = 0;
+		info->num_subdirs = 0;
+	} else {
+		int count;
+		struct exfat_chain cdir;
+
+		info->attr = ATTR_SUBDIR;
+		info->start_clu = start_clu;
+		info->size = clu_size;
+
+		exfat_chain_set(&cdir, info->start_clu,
+			EXFAT_B_TO_CLU(info->size, sbi), info->flags);
+		count = exfat_count_dir_entries(sb, &cdir);
+		if (count < 0)
+			return -EIO;
+		info->num_subdirs = count + EXFAT_MIN_SUBDIR;
+	}
+	memset(&info->create_timestamp, 0,
+			sizeof(struct exfat_date_time));
+	memset(&info->modify_timestamp, 0,
+			sizeof(struct exfat_date_time));
+	memset(&info->access_timestamp, 0,
+			sizeof(struct exfat_date_time));
+out:
+	return ret;
+}
+
+static int exfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+		bool excl)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode;
+	struct exfat_chain cdir;
+	struct exfat_dir_entry info;
+	loff_t i_pos;
+	int err;
+
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+	err = exfat_add_entry(dir, dentry->d_name.name, &cdir, TYPE_FILE,
+		&info);
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+	if (err)
+		goto unlock;
+
+	inode_inc_iversion(dir);
+	dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
+	if (IS_DIRSYNC(dir))
+		exfat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+
+	i_pos = exfat_make_i_pos(&info);
+	inode = exfat_build_inode(sb, &info, i_pos);
+	if (IS_ERR(inode))
+		goto unlock;
+
+	inode_inc_iversion(inode);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+	d_instantiate(dentry, inode);
+unlock:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	return err;
+}
+
+/* lookup a file */
+static int exfat_find(struct inode *dir, struct qstr *qname,
+		struct exfat_dir_entry *info)
+{
+	int ret, dentry, num_entries, count;
+	struct exfat_chain cdir;
+	struct exfat_uni_name uni_name;
+	struct exfat_dentry *ep, *ep2;
+	struct exfat_entry_set_cache *es = NULL;
+	struct super_block *sb = dir->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(dir);
+	struct exfat_timestamp tm;
+
+	if (qname->len == 0)
+		return -ENOENT;
+
+	/* check the validity of directory name in the given pathname */
+	ret = exfat_resolve_path_for_lookup(dir, qname->name, &cdir, &uni_name);
+	if (ret)
+		return ret;
+
+	num_entries = exfat_get_num_entries(&uni_name);
+	if (num_entries < 0)
+		return num_entries;
+
+	/* check the validation of hint_stat and initialize it if required */
+	if (ei->version != (inode_peek_iversion_raw(dir) & 0xffffffff)) {
+		ei->hint_stat.clu = cdir.dir;
+		ei->hint_stat.eidx = 0;
+		ei->version = (inode_peek_iversion_raw(dir) & 0xffffffff);
+		ei->hint_femp.eidx = EXFAT_HINT_NONE;
+	}
+
+	/* search the file name for directories */
+	dentry = exfat_find_dir_entry(sb, ei, &cdir, &uni_name,
+			num_entries, TYPE_ALL);
+
+	if ((dentry < 0) && (dentry != -EEXIST))
+		return dentry; /* -error value */
+
+	memcpy(&info->dir, &cdir.dir, sizeof(struct exfat_chain));
+	info->entry = dentry;
+	info->num_subdirs = 0;
+
+	/* root directory itself */
+	if (unlikely(dentry == -EEXIST)) {
+		int num_clu = 0;
+
+		info->type = TYPE_DIR;
+		info->attr = ATTR_SUBDIR;
+		info->flags = ALLOC_FAT_CHAIN;
+		info->start_clu = sbi->root_dir;
+		memset(&info->create_timestamp, 0,
+				sizeof(struct exfat_date_time));
+		memset(&info->modify_timestamp, 0,
+				sizeof(struct exfat_date_time));
+		memset(&info->access_timestamp, 0,
+				sizeof(struct exfat_date_time));
+
+		exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+		if (exfat_count_num_clusters(sb, &cdir, &num_clu))
+			return -EIO;
+		info->size = num_clu << sbi->cluster_size_bits;
+
+		count = exfat_count_dir_entries(sb, &cdir);
+		if (count < 0)
+			return -EIO;
+
+		info->num_subdirs = count;
+	} else {
+		es = exfat_get_dentry_set(sb, &cdir, dentry, ES_2_ENTRIES, &ep);
+		if (!es)
+			return -EIO;
+		ep2 = ep + 1;
+
+		info->type = exfat_get_entry_type(ep);
+		info->attr = le16_to_cpu(ep->file_attr);
+		info->size = le64_to_cpu(ep2->stream_valid_size);
+		if ((info->type == TYPE_FILE) && (info->size == 0)) {
+			info->flags = ALLOC_NO_FAT_CHAIN;
+			info->start_clu = EOF_CLUSTER;
+		} else {
+			info->flags = ep2->stream_flags;
+			info->start_clu = le32_to_cpu(ep2->stream_start_clu);
+		}
+
+		if (ei->start_clu == FREE_CLUSTER) {
+			exfat_fs_error(sb,
+				"non-zero size file starts with zero cluster (size : %llu, p_dir : %u, entry : 0x%08x)",
+				i_size_read(dir), ei->dir.dir, ei->entry);
+			return -EIO;
+		}
+
+		exfat_get_entry_time(ep, &tm, TM_CREATE);
+		info->create_timestamp.year = tm.year;
+		info->create_timestamp.month = tm.mon;
+		info->create_timestamp.day = tm.day;
+		info->create_timestamp.hour = tm.hour;
+		info->create_timestamp.minute = tm.min;
+		info->create_timestamp.second = tm.sec;
+		info->create_timestamp.milli_second = 0;
+
+		exfat_get_entry_time(ep, &tm, TM_MODIFY);
+		info->modify_timestamp.year = tm.year;
+		info->modify_timestamp.month = tm.mon;
+		info->modify_timestamp.day = tm.day;
+		info->modify_timestamp.hour = tm.hour;
+		info->modify_timestamp.minute = tm.min;
+		info->modify_timestamp.second = tm.sec;
+		info->modify_timestamp.milli_second = 0;
+
+		memset(&info->access_timestamp, 0,
+				sizeof(struct exfat_date_time));
+		kfree(es);
+
+		if (info->type == TYPE_DIR) {
+			exfat_chain_set(&cdir, info->start_clu,
+				EXFAT_B_TO_CLU(info->size, sbi), info->flags);
+			count = exfat_count_dir_entries(sb, &cdir);
+			if (count < 0)
+				return -EIO;
+
+			info->num_subdirs = count + EXFAT_MIN_SUBDIR;
+		}
+	}
+	return 0;
+}
+
+static int exfat_d_anon_disconn(struct dentry *dentry)
+{
+	return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED);
+}
+
+static struct dentry *exfat_lookup(struct inode *dir, struct dentry *dentry,
+		unsigned int flags)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode;
+	struct dentry *alias;
+	struct exfat_dir_entry info;
+	int err;
+	loff_t i_pos;
+	mode_t i_mode;
+
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	err = exfat_find(dir, &dentry->d_name, &info);
+	if (err) {
+		if (err == -ENOENT) {
+			inode = NULL;
+			goto out;
+		}
+		goto unlock;
+	}
+
+	i_pos = exfat_make_i_pos(&info);
+	inode = exfat_build_inode(sb, &info, i_pos);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto unlock;
+	}
+
+	i_mode = inode->i_mode;
+	alias = d_find_alias(inode);
+
+	/*
+	 * Checking "alias->d_parent == dentry->d_parent" to make sure
+	 * FS is not corrupted (especially double linked dir).
+	 */
+	if (alias && alias->d_parent == dentry->d_parent &&
+			!exfat_d_anon_disconn(alias)) {
+
+		/*
+		 * Unhashed alias is able to exist because of revalidate()
+		 * called by lookup_fast. You can easily make this status
+		 * by calling create and lookup concurrently
+		 * In such case, we reuse an alias instead of new dentry
+		 */
+		if (d_unhashed(alias)) {
+			WARN_ON(alias->d_name.hash_len !=
+				dentry->d_name.hash_len);
+			exfat_msg(sb, KERN_INFO,
+				"rehashed a dentry(%p) in read lookup", alias);
+			d_drop(dentry);
+			d_rehash(alias);
+		} else if (!S_ISDIR(i_mode)) {
+			/*
+			 * This inode has non anonymous-DCACHE_DISCONNECTED
+			 * dentry. This means, the user did ->lookup() by an
+			 * another name (longname vs 8.3 alias of it) in past.
+			 *
+			 * Switch to new one for reason of locality if possible.
+			 */
+			d_move(alias, dentry);
+		}
+		iput(inode);
+		mutex_unlock(&EXFAT_SB(sb)->s_lock);
+		return alias;
+	}
+	dput(alias);
+out:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	if (!inode)
+		exfat_d_version_set(dentry, inode_query_iversion(dir));
+
+	return d_splice_alias(inode, dentry);
+unlock:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	return ERR_PTR(err);
+}
+
+/* remove an entry, BUT don't truncate */
+static int exfat_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct exfat_chain cdir;
+	struct exfat_dentry *ep;
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode = dentry->d_inode;
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct buffer_head *bh;
+	sector_t sector;
+	int num_entries, entry, err = 0;
+
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	exfat_chain_dup(&cdir, &ei->dir);
+	entry = ei->entry;
+	if (ei->dir.dir == DIR_DELETED) {
+		exfat_msg(sb, KERN_ERR, "abnormal access to deleted dentry");
+		err = -ENOENT;
+		goto unlock;
+	}
+
+	ep = exfat_get_dentry(sb, &cdir, entry, &bh, &sector);
+	if (!ep) {
+		err = -EIO;
+		goto unlock;
+	}
+	num_entries = exfat_count_ext_entries(sb, &cdir, entry, ep);
+	if (num_entries < 0) {
+		err = -EIO;
+		brelse(bh);
+		goto unlock;
+	}
+	num_entries++;
+	brelse(bh);
+
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+	/* update the directory entry */
+	if (exfat_remove_entries(dir, &cdir, entry, 0, num_entries)) {
+		err = -EIO;
+		goto unlock;
+	}
+
+	/* This doesn't modify ei */
+	ei->dir.dir = DIR_DELETED;
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+
+	inode_inc_iversion(dir);
+	dir->i_mtime = dir->i_atime = current_time(dir);
+	if (IS_DIRSYNC(dir))
+		exfat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+
+	clear_nlink(inode);
+	inode->i_mtime = inode->i_atime = current_time(inode);
+	exfat_unhash_inode(inode);
+	exfat_d_version_set(dentry, inode_query_iversion(dir));
+unlock:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	return err;
+}
+
+static int exfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode;
+	struct exfat_dir_entry info;
+	struct exfat_chain cdir;
+	loff_t i_pos;
+	int err;
+
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+	err = exfat_add_entry(dir, dentry->d_name.name, &cdir, TYPE_DIR,
+		&info);
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+	if (err)
+		goto unlock;
+
+	inode_inc_iversion(dir);
+	dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
+	if (IS_DIRSYNC(dir))
+		exfat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+	inc_nlink(dir);
+
+	i_pos = exfat_make_i_pos(&info);
+	inode = exfat_build_inode(sb, &info, i_pos);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto unlock;
+	}
+
+	inode_inc_iversion(inode);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+	d_instantiate(dentry, inode);
+
+unlock:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	return err;
+}
+
+static int exfat_check_dir_empty(struct super_block *sb,
+		struct exfat_chain *p_dir)
+{
+	int i, dentries_per_clu;
+	unsigned int type;
+	struct exfat_chain clu;
+	struct exfat_dentry *ep;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+
+	dentries_per_clu = sbi->dentries_per_clu;
+
+	exfat_chain_dup(&clu, p_dir);
+
+	while (clu.dir != EOF_CLUSTER) {
+		for (i = 0; i < dentries_per_clu; i++) {
+			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
+			if (!ep)
+				return -EIO;
+			type = exfat_get_entry_type(ep);
+			brelse(bh);
+			if (type == TYPE_UNUSED)
+				return 0;
+
+			if (type != TYPE_FILE && type != TYPE_DIR)
+				continue;
+
+			return -ENOTEMPTY;
+		}
+
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			if (--clu.size > 0)
+				clu.dir++;
+			else
+				clu.dir = EOF_CLUSTER;
+		} else {
+			if (exfat_get_next_cluster(sb, &(clu.dir)))
+				return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct exfat_dentry *ep;
+	struct exfat_chain cdir, clu_to_free;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct buffer_head *bh;
+	sector_t sector;
+	int num_entries, entry, err;
+
+	mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
+
+	exfat_chain_dup(&cdir, &ei->dir);
+	entry = ei->entry;
+
+	if (ei->dir.dir == DIR_DELETED) {
+		exfat_msg(sb, KERN_ERR, "abnormal access to deleted dentry");
+		err = -ENOENT;
+		goto unlock;
+	}
+
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+	exfat_chain_set(&clu_to_free, ei->start_clu,
+		EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi), ei->flags);
+
+	err = exfat_check_dir_empty(sb, &clu_to_free);
+	if (err) {
+		if (err == -EIO)
+			exfat_msg(sb, KERN_ERR,
+				"failed to exfat_check_dir_empty : err(%d)",
+				err);
+		goto unlock;
+	}
+
+	ep = exfat_get_dentry(sb, &cdir, entry, &bh, &sector);
+	if (!ep) {
+		err = -EIO;
+		goto unlock;
+	}
+
+	num_entries = exfat_count_ext_entries(sb, &cdir, entry, ep);
+	if (num_entries < 0) {
+		err = -EIO;
+		brelse(bh);
+		goto unlock;
+	}
+	num_entries++;
+	brelse(bh);
+
+	err = exfat_remove_entries(dir, &cdir, entry, 0, num_entries);
+	if (err) {
+		exfat_msg(sb, KERN_ERR,
+				"failed to exfat_remove_entries : err(%d)",
+				err);
+		goto unlock;
+	}
+	ei->dir.dir = DIR_DELETED;
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+
+	inode_inc_iversion(dir);
+	dir->i_mtime = dir->i_atime = current_time(dir);
+	if (IS_DIRSYNC(dir))
+		exfat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+	drop_nlink(dir);
+
+	clear_nlink(inode);
+	inode->i_mtime = inode->i_atime = current_time(inode);
+	exfat_unhash_inode(inode);
+	exfat_d_version_set(dentry, inode_query_iversion(dir));
+unlock:
+	mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
+	return err;
+}
+
+static int exfat_rename_file(struct inode *inode, struct exfat_chain *p_dir,
+		int oldentry, struct exfat_uni_name *p_uniname,
+		struct exfat_inode_info *ei)
+{
+	int ret, num_old_entries, num_new_entries;
+	sector_t sector_old, sector_new;
+	struct exfat_dentry *epold, *epnew;
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *new_bh, *old_bh;
+	int sync = IS_DIRSYNC(inode);
+
+	epold = exfat_get_dentry(sb, p_dir, oldentry, &old_bh, &sector_old);
+	if (!epold)
+		return -EIO;
+
+	num_old_entries = exfat_count_ext_entries(sb, p_dir, oldentry, epold);
+	if (num_old_entries < 0)
+		return -EIO;
+	num_old_entries++;
+
+	num_new_entries = exfat_get_num_entries(p_uniname);
+	if (num_new_entries < 0)
+		return num_new_entries;
+
+	if (num_old_entries < num_new_entries) {
+		int newentry;
+
+		newentry =
+			exfat_find_empty_entry(inode, p_dir, num_new_entries);
+		if (newentry < 0)
+			return newentry; /* -EIO or -ENOSPC */
+
+		epnew = exfat_get_dentry(sb, p_dir, newentry, &new_bh,
+			&sector_new);
+		if (!epnew)
+			return -EIO;
+
+		memcpy(epnew, epold, DENTRY_SIZE);
+		if (exfat_get_entry_type(epnew) == TYPE_FILE) {
+			epnew->file_attr |= ATTR_ARCHIVE_LE;
+			ei->attr |= ATTR_ARCHIVE;
+		}
+		exfat_update_bh(sb, new_bh, sync);
+		brelse(old_bh);
+		brelse(new_bh);
+
+		epold = exfat_get_dentry(sb, p_dir, oldentry + 1, &old_bh,
+			&sector_old);
+		epnew = exfat_get_dentry(sb, p_dir, newentry + 1, &new_bh,
+			&sector_new);
+		if (!epold || !epnew)
+			return -EIO;
+
+		memcpy(epnew, epold, DENTRY_SIZE);
+		exfat_update_bh(sb, new_bh, sync);
+		brelse(old_bh);
+		brelse(new_bh);
+
+		ret = exfat_init_ext_entry(inode, p_dir, newentry,
+			num_new_entries, p_uniname);
+		if (ret)
+			return ret;
+
+		exfat_remove_entries(inode, p_dir, oldentry, 0,
+			num_old_entries);
+		ei->entry = newentry;
+	} else {
+		if (exfat_get_entry_type(epold) == TYPE_FILE) {
+			epold->file_attr |= ATTR_ARCHIVE_LE;
+			ei->attr |= ATTR_ARCHIVE;
+		}
+		exfat_update_bh(sb, old_bh, sync);
+		brelse(old_bh);
+		ret = exfat_init_ext_entry(inode, p_dir, oldentry,
+			num_new_entries, p_uniname);
+		if (ret)
+			return ret;
+
+		exfat_remove_entries(inode, p_dir, oldentry, num_new_entries,
+			num_old_entries);
+	}
+	return 0;
+}
+
+static int exfat_move_file(struct inode *inode, struct exfat_chain *p_olddir,
+		int oldentry, struct exfat_chain *p_newdir,
+		struct exfat_uni_name *p_uniname, struct exfat_inode_info *ei)
+{
+	int ret, newentry, num_new_entries, num_old_entries;
+	sector_t sector_mov, sector_new;
+	struct exfat_dentry *epmov, *epnew;
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *mov_bh, *new_bh;
+
+	epmov = exfat_get_dentry(sb, p_olddir, oldentry, &mov_bh, &sector_mov);
+	if (!epmov)
+		return -EIO;
+
+	/* check if the source and target directory is the same */
+	if (exfat_get_entry_type(epmov) == TYPE_DIR &&
+	    le32_to_cpu(epmov->stream_start_clu) == p_newdir->dir)
+		return -EINVAL;
+
+	num_old_entries = exfat_count_ext_entries(sb, p_olddir, oldentry,
+		epmov);
+	if (num_old_entries < 0)
+		return -EIO;
+	num_old_entries++;
+
+	num_new_entries = exfat_get_num_entries(p_uniname);
+	if (num_new_entries < 0)
+		return num_new_entries;
+
+	newentry = exfat_find_empty_entry(inode, p_newdir, num_new_entries);
+	if (newentry < 0)
+		return newentry; /* -EIO or -ENOSPC */
+
+	epnew = exfat_get_dentry(sb, p_newdir, newentry, &new_bh, &sector_new);
+	if (!epnew)
+		return -EIO;
+
+	memcpy(epnew, epmov, DENTRY_SIZE);
+	if (exfat_get_entry_type(epnew) == TYPE_FILE) {
+		epnew->file_attr |= ATTR_ARCHIVE_LE;
+		ei->attr |= ATTR_ARCHIVE;
+	}
+	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
+	brelse(mov_bh);
+	brelse(new_bh);
+
+	epmov = exfat_get_dentry(sb, p_olddir, oldentry + 1, &mov_bh,
+		&sector_mov);
+	epnew = exfat_get_dentry(sb, p_newdir, newentry + 1, &new_bh,
+		&sector_new);
+	if (!epmov || !epnew)
+		return -EIO;
+
+	memcpy(epnew, epmov, DENTRY_SIZE);
+	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
+	brelse(mov_bh);
+	brelse(new_bh);
+
+	ret = exfat_init_ext_entry(inode, p_newdir, newentry, num_new_entries,
+		p_uniname);
+	if (ret)
+		return ret;
+
+	exfat_remove_entries(inode, p_olddir, oldentry, 0, num_old_entries);
+
+	exfat_chain_set(&ei->dir, p_newdir->dir, p_newdir->size,
+		p_newdir->flags);
+
+	ei->entry = newentry;
+	return 0;
+}
+
+static void exfat_update_parent_info(struct exfat_inode_info *ei,
+		struct inode *parent_inode)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(parent_inode->i_sb);
+	struct exfat_inode_info *parent_ei = EXFAT_I(parent_inode);
+	loff_t parent_isize = i_size_read(parent_inode);
+
+	/*
+	 * the problem that struct exfat_inode_info caches wrong parent info.
+	 *
+	 * because of flag-mismatch of ei->dir,
+	 * there is abnormal traversing cluster chain.
+	 */
+	if (unlikely(parent_ei->flags != ei->dir.flags ||
+		     parent_isize != EXFAT_CLU_TO_B(ei->dir.size, sbi) ||
+		     parent_ei->start_clu != ei->dir.dir)) {
+		exfat_chain_set(&ei->dir, parent_ei->start_clu,
+			EXFAT_B_TO_CLU_ROUND_UP(parent_isize, sbi),
+			parent_ei->flags);
+	}
+}
+
+/* rename or move a old file into a new file */
+static int __exfat_rename(struct inode *old_parent_inode,
+		struct exfat_inode_info *ei, struct inode *new_parent_inode,
+		struct dentry *new_dentry)
+{
+	int ret;
+	int dentry;
+	struct exfat_chain olddir, newdir;
+	struct exfat_chain *p_dir = NULL;
+	struct exfat_uni_name uni_name;
+	struct exfat_dentry *ep;
+	struct super_block *sb = old_parent_inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	const unsigned char *new_path = new_dentry->d_name.name;
+	struct inode *new_inode = new_dentry->d_inode;
+	int num_entries;
+	struct exfat_inode_info *new_ei = NULL;
+	unsigned int new_entry_type = TYPE_UNUSED;
+	int new_entry = 0;
+	struct buffer_head *old_bh, *new_bh = NULL;
+
+	/* check the validity of pointer parameters */
+	if (new_path == NULL || strlen(new_path) == 0)
+		return -EINVAL;
+
+	if (ei->dir.dir == DIR_DELETED) {
+		exfat_msg(sb, KERN_ERR,
+				"abnormal access to deleted source dentry");
+		return -ENOENT;
+	}
+
+	exfat_update_parent_info(ei, old_parent_inode);
+
+	exfat_chain_dup(&olddir, &ei->dir);
+	dentry = ei->entry;
+
+	ep = exfat_get_dentry(sb, &olddir, dentry, &old_bh, NULL);
+	if (!ep) {
+		ret = -EIO;
+		goto out;
+	}
+	brelse(old_bh);
+
+	/* check whether new dir is existing directory and empty */
+	if (new_inode) {
+		ret = -EIO;
+		new_ei = EXFAT_I(new_inode);
+
+		if (new_ei->dir.dir == DIR_DELETED) {
+			exfat_msg(sb, KERN_ERR,
+				"abnormal access to deleted target dentry");
+			goto out;
+		}
+
+		exfat_update_parent_info(new_ei, new_parent_inode);
+
+		p_dir = &(new_ei->dir);
+		new_entry = new_ei->entry;
+		ep = exfat_get_dentry(sb, p_dir, new_entry, &new_bh, NULL);
+		if (!ep)
+			goto out;
+
+		new_entry_type = exfat_get_entry_type(ep);
+		brelse(new_bh);
+
+		/* if new_inode exists, update ei */
+		if (new_entry_type == TYPE_DIR) {
+			struct exfat_chain new_clu;
+
+			new_clu.dir = new_ei->start_clu;
+			new_clu.size =
+				EXFAT_B_TO_CLU_ROUND_UP(i_size_read(new_inode),
+				sbi);
+			new_clu.flags = new_ei->flags;
+
+			ret = exfat_check_dir_empty(sb, &new_clu);
+			if (ret)
+				goto out;
+		}
+	}
+
+	/* check the validity of directory name in the given new pathname */
+	ret = exfat_resolve_path(new_parent_inode, new_path, &newdir,
+			&uni_name);
+	if (ret)
+		goto out;
+
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+
+	if (olddir.dir == newdir.dir)
+		ret = exfat_rename_file(new_parent_inode, &olddir, dentry,
+				&uni_name, ei);
+	else
+		ret = exfat_move_file(new_parent_inode, &olddir, dentry,
+				&newdir, &uni_name, ei);
+
+	if (!ret && new_inode) {
+		/* delete entries of new_dir */
+		ep = exfat_get_dentry(sb, p_dir, new_entry, &new_bh, NULL);
+		if (!ep) {
+			ret = -EIO;
+			goto del_out;
+		}
+
+		num_entries = exfat_count_ext_entries(sb, p_dir, new_entry, ep);
+		if (num_entries < 0) {
+			ret = -EIO;
+			goto del_out;
+		}
+		brelse(new_bh);
+
+		if (exfat_remove_entries(new_inode, p_dir, new_entry, 0,
+				num_entries + 1)) {
+			ret = -EIO;
+			goto del_out;
+		}
+
+		/* Free the clusters if new_inode is a dir(as if exfat_rmdir) */
+		if (new_entry_type == TYPE_DIR) {
+			/* new_ei, new_clu_to_free */
+			struct exfat_chain new_clu_to_free;
+
+			exfat_chain_set(&new_clu_to_free, new_ei->start_clu,
+				EXFAT_B_TO_CLU_ROUND_UP(i_size_read(new_inode),
+				sbi), new_ei->flags);
+
+			if (exfat_free_cluster(new_inode, &new_clu_to_free)) {
+				/* just set I/O error only */
+				ret = -EIO;
+			}
+
+			i_size_write(new_inode, 0);
+			new_ei->start_clu = EOF_CLUSTER;
+			new_ei->flags = ALLOC_NO_FAT_CHAIN;
+		}
+del_out:
+		/* Update new_inode ei
+		 * Prevent syncing removed new_inode
+		 * (new_ei is already initialized above code ("if (new_inode)")
+		 */
+		new_ei->dir.dir = DIR_DELETED;
+	}
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+out:
+	return ret;
+}
+
+static int exfat_rename(struct inode *old_dir, struct dentry *old_dentry,
+		struct inode *new_dir, struct dentry *new_dentry,
+		unsigned int flags)
+{
+	struct inode *old_inode, *new_inode;
+	struct super_block *sb = old_dir->i_sb;
+	loff_t i_pos;
+	int err;
+
+	/*
+	 * The VFS already checks for existence, so for local filesystems
+	 * the RENAME_NOREPLACE implementation is equivalent to plain rename.
+	 * Don't support any other flags
+	 */
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	old_inode = old_dentry->d_inode;
+	new_inode = new_dentry->d_inode;
+
+	err = __exfat_rename(old_dir, EXFAT_I(old_inode), new_dir, new_dentry);
+	if (err)
+		goto unlock;
+
+	inode_inc_iversion(new_dir);
+	new_dir->i_ctime = new_dir->i_mtime = new_dir->i_atime =
+		current_time(new_dir);
+	if (IS_DIRSYNC(new_dir))
+		exfat_sync_inode(new_dir);
+	else
+		mark_inode_dirty(new_dir);
+
+	i_pos = ((loff_t)EXFAT_I(old_inode)->dir.dir << 32) |
+		(EXFAT_I(old_inode)->entry & 0xffffffff);
+	exfat_unhash_inode(old_inode);
+	exfat_hash_inode(old_inode, i_pos);
+	if (IS_DIRSYNC(new_dir))
+		exfat_sync_inode(old_inode);
+	else
+		mark_inode_dirty(old_inode);
+
+	if (S_ISDIR(old_inode->i_mode) && old_dir != new_dir) {
+		drop_nlink(old_dir);
+		if (!new_inode)
+			inc_nlink(new_dir);
+	}
+
+	inode_inc_iversion(old_dir);
+	old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
+	if (IS_DIRSYNC(old_dir))
+		exfat_sync_inode(old_dir);
+	else
+		mark_inode_dirty(old_dir);
+
+	if (new_inode) {
+		exfat_unhash_inode(new_inode);
+
+		/* skip drop_nlink if new_inode already has been dropped */
+		if (new_inode->i_nlink) {
+			drop_nlink(new_inode);
+			if (S_ISDIR(new_inode->i_mode))
+				drop_nlink(new_inode);
+		} else {
+			exfat_msg(sb, KERN_WARNING,
+					"abnormal access to an inode dropped");
+			WARN_ON(new_inode->i_nlink == 0);
+		}
+		new_inode->i_ctime = current_time(new_inode);
+	}
+
+unlock:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	return err;
+}
+
+const struct inode_operations exfat_dir_inode_operations = {
+	.create		= exfat_create,
+	.lookup		= exfat_lookup,
+	.unlink		= exfat_unlink,
+	.mkdir		= exfat_mkdir,
+	.rmdir		= exfat_rmdir,
+	.rename		= exfat_rename,
+	.setattr	= exfat_setattr,
+	.getattr	= exfat_getattr,
+};
-- 
2.17.1

Re: [PATCH v6 03/13] exfat: add inode operations

[Vyacheslav Dubeyko]

On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of inode operations for exfat.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
>  fs/exfat/inode.c |  693 ++++++++++++++++++++++
>  fs/exfat/namei.c | 1459
> ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 2152 insertions(+)
>  create mode 100644 fs/exfat/inode.c
>  create mode 100644 fs/exfat/namei.c
> 
> diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
> new file mode 100644
> index 000000000000..e1e20e74c92a
> --- /dev/null
> +++ b/fs/exfat/inode.c
> @@ -0,0 +1,693 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/buffer_head.h>
> +#include <linux/mpage.h>
> +#include <linux/bio.h>
> +#include <linux/blkdev.h>
> +#include <linux/time.h>
> +#include <linux/writeback.h>
> +#include <linux/uio.h>
> +#include <linux/random.h>
> +#include <linux/iversion.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +/* 2-level option flag */
> +enum {
> +	BMAP_NOT_CREATE,
> +	BMAP_ADD_CLUSTER,
> +};
> +
> +static int __exfat_write_inode(struct inode *inode, int sync)
> +{
> +	int ret = -EIO;
> +	unsigned long long on_disk_size;
> +	struct exfat_timestamp tm;
> +	struct exfat_dentry *ep, *ep2;
> +	struct exfat_entry_set_cache *es = NULL;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	unsigned char is_dir = (ei->type == TYPE_DIR) ? 1 : 0;

The unsigned char type instead of boolean one? What's the point?


> +	struct exfat_dir_entry info;
> +
> +	if (inode->i_ino == EXFAT_ROOT_INO)
> +		return 0;
> +
> +	info.attr = exfat_make_attr(inode);
> +	info.size = i_size_read(inode);
> +
> +	exfat_time_unix2fat(sbi, &inode->i_mtime,
> &info.modify_timestamp);
> +	exfat_time_unix2fat(sbi, &inode->i_ctime,
> &info.create_timestamp);
> +	exfat_time_unix2fat(sbi, &inode->i_atime,
> &info.access_timestamp);
> +
> +	/*
> +	 * If the indode is already unlinked, there is no need for
> updating it.
> +	 */
> +	if (ei->dir.dir == DIR_DELETED)
> +		return 0;
> +
> +	if (is_dir && ei->dir.dir == sbi->root_dir && ei->entry == -1)
> +		return 0;
> +
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +
> +	/* get the directory entry of given file or directory */
> +	es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
> ES_ALL_ENTRIES,
> +		&ep);
> +	if (!es)
> +		return -EIO;
> +	ep2 = ep + 1;

What if the ep points out on the latest item in the sequence? It looks
like that ep2 could point out on the garbage.

> +
> +	ep->file_attr = cpu_to_le16(info.attr);
> +
> +	/* set FILE_INFO structure using the acquired struct
> exfat_dentry */
> +	tm.sec  = info.create_timestamp.second;
> +	tm.min  = info.create_timestamp.minute;
> +	tm.hour = info.create_timestamp.hour;
> +	tm.day  = info.create_timestamp.day;
> +	tm.mon  = info.create_timestamp.month;
> +	tm.year = info.create_timestamp.year;
> +	exfat_set_entry_time(ep, &tm, TM_CREATE);
> +
> +	tm.sec  = info.modify_timestamp.second;
> +	tm.min  = info.modify_timestamp.minute;
> +	tm.hour = info.modify_timestamp.hour;
> +	tm.day  = info.modify_timestamp.day;
> +	tm.mon  = info.modify_timestamp.month;
> +	tm.year = info.modify_timestamp.year;
> +	exfat_set_entry_time(ep, &tm, TM_MODIFY);
> +
> +	/* File size should be zero if there is no cluster allocated */
> +	on_disk_size = info.size;
> +
> +	if (ei->start_clu == EOF_CLUSTER)
> +		on_disk_size = 0;
> +
> +	ep2->stream_valid_size = cpu_to_le64(on_disk_size);
> +	ep2->stream_size = ep2->stream_valid_size;
> +
> +	ret = exfat_update_dir_chksum_with_entry_set(sb, es, sync);
> +	kfree(es);

The exfat_get_dentry_set() allocates the es by kmalloc? Am I correct?


> +	return ret;
> +}
> +
> +int exfat_write_inode(struct inode *inode, struct writeback_control
> *wbc)
> +{
> +	int ret;
> +
> +	mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
> +	ret = __exfat_write_inode(inode, wbc->sync_mode ==
> WB_SYNC_ALL);
> +	mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
> +
> +	return ret;
> +}
> +
> +void exfat_sync_inode(struct inode *inode)
> +{
> +	lockdep_assert_held(&EXFAT_SB(inode->i_sb)->s_lock);
> +	__exfat_write_inode(inode, 1);
> +}
> +
> +/*
> + * Input: inode, (logical) clu_offset, target allocation area
> + * Output: errcode, cluster number
> + * *clu = (~0), if it's unable to allocate a new cluster
> + */
> +static int exfat_map_cluster(struct inode *inode, unsigned int
> clu_offset,
> +		unsigned int *clu, int create)
> +{
> +	int ret, modified = false;
> +	unsigned int last_clu;
> +	struct exfat_chain new_clu;
> +	struct exfat_dentry *ep;
> +	struct exfat_entry_set_cache *es = NULL;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	unsigned int local_clu_offset = clu_offset;
> +	unsigned int num_to_be_allocated = 0, num_clusters = 0;
> +
> +	ei->rwoffset = EXFAT_CLU_TO_B(clu_offset, sbi);
> +
> +	if (EXFAT_I(inode)->i_size_ondisk > 0)
> +		num_clusters =
> +			EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)-
> >i_size_ondisk,
> +			sbi);
> +
> +	if (clu_offset >= num_clusters)
> +		num_to_be_allocated = clu_offset - num_clusters + 1;
> +
> +	if (!create && (num_to_be_allocated > 0)) {
> +		*clu = EOF_CLUSTER;
> +		return 0;
> +	}
> +
> +	*clu = last_clu = ei->start_clu;
> +
> +	if (ei->flags == ALLOC_NO_FAT_CHAIN) {
> +		if (clu_offset > 0 && *clu != EOF_CLUSTER) {
> +			last_clu += clu_offset - 1;
> +
> +			if (clu_offset == num_clusters)
> +				*clu = EOF_CLUSTER;
> +			else
> +				*clu += clu_offset;
> +		}
> +	} else if (ei->type == TYPE_FILE) {
> +		unsigned int fclus = 0;
> +		int err = exfat_get_cluster(inode, clu_offset,
> +				&fclus, clu, &last_clu, 1);
> +		if (err)
> +			return -EIO;
> +
> +		clu_offset -= fclus;
> +	} else {
> +		/* hint information */
> +		if (clu_offset > 0 && ei->hint_bmap.off != EOF_CLUSTER
> &&
> +		    ei->hint_bmap.off > 0 && clu_offset >= ei-
> >hint_bmap.off) {
> +			clu_offset -= ei->hint_bmap.off;
> +			/* hint_bmap.clu should be valid */
> +			WARN_ON(ei->hint_bmap.clu < 2);
> +			*clu = ei->hint_bmap.clu;
> +		}
> +
> +		while (clu_offset > 0 && *clu != EOF_CLUSTER) {
> +			last_clu = *clu;
> +			if (exfat_get_next_cluster(sb, clu))
> +				return -EIO;
> +			clu_offset--;
> +		}
> +	}
> +
> +	if (*clu == EOF_CLUSTER) {
> +		exfat_set_vol_flags(sb, VOL_DIRTY);
> +
> +		new_clu.dir = (last_clu == EOF_CLUSTER) ?
> +				EOF_CLUSTER : last_clu + 1;
> +		new_clu.size = 0;
> +		new_clu.flags = ei->flags;
> +
> +		/* allocate a cluster */
> +		if (num_to_be_allocated < 1) {
> +			/* Broken FAT (i_sze > allocated FAT) */
> +			exfat_fs_error(sb, "broken FAT chain.");
> +			return -EIO;
> +		}
> +
> +		ret = exfat_alloc_cluster(inode, num_to_be_allocated,
> &new_clu);
> +		if (ret)
> +			return ret;
> +
> +		if (new_clu.dir == EOF_CLUSTER || new_clu.dir ==
> FREE_CLUSTER) {
> +			exfat_fs_error(sb,
> +				"bogus cluster new allocated (last_clu
> : %u, new_clu : %u)",
> +				last_clu, new_clu.dir);
> +			return -EIO;
> +		}
> +
> +		/* append to the FAT chain */
> +		if (last_clu == EOF_CLUSTER) {
> +			if (new_clu.flags == ALLOC_FAT_CHAIN)
> +				ei->flags = ALLOC_FAT_CHAIN;
> +			ei->start_clu = new_clu.dir;
> +			modified = true;
> +		} else {
> +			if (new_clu.flags != ei->flags) {
> +				/* no-fat-chain bit is disabled,
> +				 * so fat-chain should be synced with
> +				 * alloc-bitmap
> +				 */
> +				exfat_chain_cont_cluster(sb, ei-
> >start_clu,
> +					num_clusters);
> +				ei->flags = ALLOC_FAT_CHAIN;
> +				modified = true;
> +			}
> +			if (new_clu.flags == ALLOC_FAT_CHAIN)
> +				if (exfat_ent_set(sb, last_clu,
> new_clu.dir))
> +					return -EIO;
> +		}
> +
> +		num_clusters += num_to_be_allocated;
> +		*clu = new_clu.dir;
> +
> +		if (ei->dir.dir != DIR_DELETED) {
> +			es = exfat_get_dentry_set(sb, &(ei->dir), ei-
> >entry,
> +				ES_ALL_ENTRIES, &ep);
> +			if (!es)
> +				return -EIO;
> +			/* get stream entry */
> +			ep++;
> +
> +			/* update directory entry */
> +			if (modified) {
> +				if (ep->stream_flags != ei->flags)
> +					ep->stream_flags = ei->flags;
> +
> +				if (le32_to_cpu(ep->stream_start_clu)
> !=
> +						ei->start_clu)
> +					ep->stream_start_clu =
> +						cpu_to_le32(ei-
> >start_clu);
> +
> +				ep->stream_valid_size =
> +					cpu_to_le64(i_size_read(inode))
> ;
> +				ep->stream_size = ep-
> >stream_valid_size;
> +			}
> +
> +			if (exfat_update_dir_chksum_with_entry_set(sb,
> es,
> +			    inode_needs_sync(inode)))
> +				return -EIO;
> +			kfree(es);
> +
> +		} /* end of if != DIR_DELETED */
> +
> +		inode->i_blocks +=
> +			num_to_be_allocated << sbi->sect_per_clus_bits;
> +
> +		/*
> +		 * Move *clu pointer along FAT chains (hole care)
> because the
> +		 * caller of this function expect *clu to be the last
> cluster.
> +		 * This only works when num_to_be_allocated >= 2,
> +		 * *clu = (the first cluster of the allocated chain) =>
> +		 * (the last cluster of ...)
> +		 */
> +		if (ei->flags == ALLOC_NO_FAT_CHAIN) {
> +			*clu += num_to_be_allocated - 1;
> +		} else {
> +			while (num_to_be_allocated > 1) {
> +				if (exfat_get_next_cluster(sb, clu))
> +					return -EIO;
> +				num_to_be_allocated--;
> +			}
> +		}
> +
> +	}
> +
> +	/* hint information */
> +	ei->hint_bmap.off = local_clu_offset;
> +	ei->hint_bmap.clu = *clu;
> +
> +	return 0;
> +}
> +
> +static int exfat_bmap(struct inode *inode, sector_t sector, sector_t
> *phys,
> +		unsigned long *mapped_blocks, int *create)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	sector_t last_block;
> +	unsigned int cluster, clu_offset, sec_offset;
> +	int err = 0;
> +
> +	*phys = 0;
> +	*mapped_blocks = 0;
> +
> +	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
> +	if (sector >= last_block && *create == BMAP_NOT_CREATE)
> +		return 0;
> +
> +	/* Is this block already allocated? */
> +	clu_offset = sector >> sbi->sect_per_clus_bits;  /* cluster
> offset */
> +
> +	err = exfat_map_cluster(inode, clu_offset, &cluster,
> +		*create & BMAP_ADD_CLUSTER);
> +	if (err) {
> +		if (err != -ENOSPC)
> +			return -EIO;
> +		return err;
> +	}
> +
> +	if (cluster != EOF_CLUSTER) {
> +		/* sector offset in cluster */
> +		sec_offset = sector & (sbi->sect_per_clus - 1);
> +
> +		*phys = exfat_cluster_to_sector(sbi, cluster) +
> sec_offset;
> +		*mapped_blocks = sbi->sect_per_clus - sec_offset;
> +	}
> +
> +	if (sector < last_block)
> +		*create = BMAP_NOT_CREATE;
> +	return 0;
> +}
> +
> +static int exfat_get_block(struct inode *inode, sector_t iblock,
> +		struct buffer_head *bh_result, int create)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	unsigned long max_blocks = bh_result->b_size >> inode-
> >i_blkbits;
> +	int err = 0;
> +	unsigned long mapped_blocks;
> +	sector_t phys;
> +	loff_t pos;
> +	int bmap_create = create ? BMAP_ADD_CLUSTER : BMAP_NOT_CREATE;
> +
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	err = exfat_bmap(inode, iblock, &phys, &mapped_blocks,
> &bmap_create);
> +	if (err) {
> +		if (err != -ENOSPC)
> +			exfat_fs_error_ratelimit(sb,
> +				"failed to bmap (inode : %p iblock :
> %llu, err : %d)",
> +				inode, (unsigned long long)iblock,
> err);
> +		goto unlock_ret;
> +	}
> +
> +	if (phys) {
> +		max_blocks = min(mapped_blocks, max_blocks);
> +
> +		/* Treat newly added block / cluster */
> +		if (bmap_create || buffer_delay(bh_result)) {
> +			/* Update i_size_ondisk */
> +			pos = EXFAT_BLK_TO_B((iblock + 1), sb);
> +			if (EXFAT_I(inode)->i_size_ondisk < pos)
> +				EXFAT_I(inode)->i_size_ondisk = pos;
> +
> +			if (bmap_create) {
> +				if (buffer_delay(bh_result) &&
> +				    pos > EXFAT_I(inode)-
> >i_size_aligned) {
> +					exfat_fs_error(sb,
> +						"requested for bmap out
> of range(pos : (%llu) > i_size_aligned(%llu)\n",
> +						pos,
> +						EXFAT_I(inode)-
> >i_size_aligned);
> +					err = -EIO;
> +					goto unlock_ret;
> +				}
> +				set_buffer_new(bh_result);
> +
> +				/*
> +				 * adjust i_size_aligned if
> i_size_ondisk is
> +				 * bigger than it. (i.e. non-DA)
> +				 */
> +				if (EXFAT_I(inode)->i_size_ondisk >
> +				    EXFAT_I(inode)->i_size_aligned) {
> +					EXFAT_I(inode)->i_size_aligned
> =
> +						EXFAT_I(inode)-
> >i_size_ondisk;
> +				}
> +			}
> +
> +			if (buffer_delay(bh_result))
> +				clear_buffer_delay(bh_result);
> +		}
> +		map_bh(bh_result, sb, phys);
> +	}
> +
> +	bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb);
> +unlock_ret:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	return err;
> +}
> +
> +static int exfat_readpage(struct file *file, struct page *page)
> +{
> +	return mpage_readpage(page, exfat_get_block);
> +}
> +
> +static int exfat_readpages(struct file *file, struct address_space
> *mapping,
> +		struct list_head *pages, unsigned int nr_pages)
> +{
> +	return mpage_readpages(mapping, pages, nr_pages,
> exfat_get_block);
> +}
> +
> +static int exfat_writepage(struct page *page, struct
> writeback_control *wbc)
> +{
> +	return block_write_full_page(page, exfat_get_block, wbc);
> +}
> +
> +static int exfat_writepages(struct address_space *mapping,
> +		struct writeback_control *wbc)
> +{
> +	return mpage_writepages(mapping, wbc, exfat_get_block);
> +}
> +
> +static void exfat_write_failed(struct address_space *mapping, loff_t
> to)
> +{
> +	struct inode *inode = mapping->host;
> +
> +	if (to > i_size_read(inode)) {
> +		truncate_pagecache(inode, i_size_read(inode));
> +		exfat_truncate(inode, EXFAT_I(inode)->i_size_aligned);
> +	}
> +}
> +
> +static int exfat_write_begin(struct file *file, struct address_space
> *mapping,
> +		loff_t pos, unsigned int len, unsigned int flags,
> +		struct page **pagep, void **fsdata)
> +{
> +	int ret;
> +
> +	*pagep = NULL;
> +	ret = cont_write_begin(file, mapping, pos, len, flags, pagep,
> fsdata,
> +			       exfat_get_block,
> +			       &EXFAT_I(mapping->host)->i_size_ondisk);
> +
> +	if (ret < 0)
> +		exfat_write_failed(mapping, pos+len);
> +
> +	return ret;
> +}
> +
> +static int exfat_write_end(struct file *file, struct address_space
> *mapping,
> +		loff_t pos, unsigned int len, unsigned int copied,
> +		struct page *pagep, void *fsdata)
> +{
> +	struct inode *inode = mapping->host;
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	int err;
> +
> +	err = generic_write_end(file, mapping, pos, len, copied, pagep,
> fsdata);
> +
> +	if (EXFAT_I(inode)->i_size_aligned < i_size_read(inode)) {
> +		exfat_fs_error(inode->i_sb,
> +			"invalid size(size(%llu) > aligned(%llu)\n",
> +			i_size_read(inode), EXFAT_I(inode)-
> >i_size_aligned);
> +		return -EIO;
> +	}
> +
> +	if (err < len)
> +		exfat_write_failed(mapping, pos+len);
> +
> +	if (!(err < 0) && !(ei->attr & ATTR_ARCHIVE)) {
> +		inode->i_mtime = inode->i_ctime = current_time(inode);
> +		ei->attr |= ATTR_ARCHIVE;
> +		mark_inode_dirty(inode);
> +	}
> +
> +	return err;
> +}
> +
> +static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter
> *iter)
> +{
> +	struct address_space *mapping = iocb->ki_filp->f_mapping;
> +	struct inode *inode = mapping->host;
> +	loff_t size = iocb->ki_pos + iov_iter_count(iter);
> +	int rw = iov_iter_rw(iter);
> +	ssize_t ret;
> +
> +	if (rw == WRITE) {
> +		/*
> +		 * FIXME: blockdev_direct_IO() doesn't use
> ->write_begin(),
> +		 * so we need to update the ->i_size_aligned to block
> boundary.
> +		 *
> +		 * But we must fill the remaining area or hole by nul
> for
> +		 * updating ->i_size_aligned
> +		 *
> +		 * Return 0, and fallback to normal buffered write.
> +		 */
> +		if (EXFAT_I(inode)->i_size_aligned < size)
> +			return 0;
> +	}
> +
> +	/*
> +	 * Need to use the DIO_LOCKING for avoiding the race
> +	 * condition of exfat_get_block() and ->truncate().
> +	 */
> +	ret = blockdev_direct_IO(iocb, inode, iter, exfat_get_block);
> +	if (ret < 0 && (rw & WRITE))
> +		exfat_write_failed(mapping, size);
> +	return ret;
> +}
> +
> +static sector_t exfat_aop_bmap(struct address_space *mapping,
> sector_t block)
> +{
> +	sector_t blocknr;
> +
> +	/* exfat_get_cluster() assumes the requested blocknr isn't
> truncated. */
> +	down_read(&EXFAT_I(mapping->host)->truncate_lock);
> +	blocknr = generic_block_bmap(mapping, block, exfat_get_block);
> +	up_read(&EXFAT_I(mapping->host)->truncate_lock);
> +	return blocknr;
> +}
> +
> +static const struct address_space_operations exfat_aops = {
> +	.readpage	= exfat_readpage,
> +	.readpages	= exfat_readpages,
> +	.writepage	= exfat_writepage,
> +	.writepages	= exfat_writepages,
> +	.write_begin	= exfat_write_begin,
> +	.write_end	= exfat_write_end,
> +	.direct_IO	= exfat_direct_IO,
> +	.bmap		= exfat_aop_bmap
> +};
> +
> +static inline unsigned long exfat_hash(loff_t i_pos)
> +{
> +	return hash_32(i_pos, EXFAT_HASH_BITS);
> +}
> +
> +void exfat_hash_inode(struct inode *inode, loff_t i_pos)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
> +	struct hlist_head *head = sbi->inode_hashtable +
> exfat_hash(i_pos);
> +
> +	spin_lock(&sbi->inode_hash_lock);
> +	EXFAT_I(inode)->i_pos = i_pos;
> +	hlist_add_head(&EXFAT_I(inode)->i_hash_fat, head);
> +	spin_unlock(&sbi->inode_hash_lock);
> +}
> +
> +void exfat_unhash_inode(struct inode *inode)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
> +
> +	spin_lock(&sbi->inode_hash_lock);
> +	hlist_del_init(&EXFAT_I(inode)->i_hash_fat);
> +	EXFAT_I(inode)->i_pos = 0;
> +	spin_unlock(&sbi->inode_hash_lock);
> +}
> +
> +struct inode *exfat_iget(struct super_block *sb, loff_t i_pos)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *info;
> +	struct hlist_head *head = sbi->inode_hashtable +
> exfat_hash(i_pos);
> +	struct inode *inode = NULL;
> +
> +	spin_lock(&sbi->inode_hash_lock);
> +	hlist_for_each_entry(info, head, i_hash_fat) {
> +		WARN_ON(info->vfs_inode.i_sb != sb);
> +
> +		if (i_pos != info->i_pos)
> +			continue;
> +		inode = igrab(&info->vfs_inode);
> +		if (inode)
> +			break;
> +	}
> +	spin_unlock(&sbi->inode_hash_lock);
> +	return inode;
> +}
> +
> +/* doesn't deal with root inode */
> +static int exfat_fill_inode(struct inode *inode, struct
> exfat_dir_entry *info)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	loff_t size = info->size;
> +
> +	memcpy(&ei->dir, &info->dir, sizeof(struct exfat_chain));
> +	ei->entry = info->entry;
> +	ei->attr = info->attr;
> +	ei->start_clu = info->start_clu;
> +	ei->flags = info->flags;
> +	ei->type = info->type;
> +
> +	ei->version = 0;
> +	ei->hint_stat.eidx = 0;
> +	ei->hint_stat.clu = info->start_clu;
> +	ei->hint_femp.eidx = EXFAT_HINT_NONE;
> +	ei->rwoffset = 0;
> +	ei->hint_bmap.off = EOF_CLUSTER;
> +	ei->i_pos = 0;
> +
> +	inode->i_uid = sbi->options.fs_uid;
> +	inode->i_gid = sbi->options.fs_gid;
> +	inode_inc_iversion(inode);
> +	inode->i_generation = prandom_u32();
> +
> +	if (info->attr & ATTR_SUBDIR) { /* directory */
> +		inode->i_generation &= ~1;
> +		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);

What's about constants instead of 0777 here? By the way, are you sure
that it's proper permissions set?

> +		inode->i_op = &exfat_dir_inode_operations;
> +		inode->i_fop = &exfat_dir_operations;
> +		set_nlink(inode, info->num_subdirs);
> +	} else { /* regular file */
> +		inode->i_generation |= 1;
> +		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);

What's about constants instead of 0777 here? By the way, are you sure
that it's proper permissions set?


> +		inode->i_op = &exfat_file_inode_operations;
> +		inode->i_fop = &exfat_file_operations;
> +		inode->i_mapping->a_ops = &exfat_aops;
> +		inode->i_mapping->nrpages = 0;
> +	}
> +
> +	i_size_write(inode, size);
> +
> +	/* ondisk and aligned size should be aligned with block size */
> +	if (size & (inode->i_sb->s_blocksize - 1)) {
> +		size |= (inode->i_sb->s_blocksize - 1);
> +		size++;
> +	}
> +
> +	ei->i_size_aligned = size;
> +	ei->i_size_ondisk = size;
> +
> +	exfat_save_attr(inode, info->attr);
> +
> +	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size -
> 1)) &
> +		~(sbi->cluster_size - 1)) >> inode->i_blkbits;
> +
> +	exfat_time_fat2unix(sbi, &inode->i_mtime, &info-
> >modify_timestamp);
> +	exfat_time_fat2unix(sbi, &inode->i_ctime, &info-
> >create_timestamp);
> +	exfat_time_fat2unix(sbi, &inode->i_atime, &info-
> >access_timestamp);
> +
> +	exfat_cache_init_inode(inode);
> +
> +	return 0;
> +}
> +
> +struct inode *exfat_build_inode(struct super_block *sb,
> +		struct exfat_dir_entry *info, loff_t i_pos)
> +{
> +	struct inode *inode;
> +	int err;
> +
> +	inode = exfat_iget(sb, i_pos);
> +	if (inode)
> +		goto out;
> +	inode = new_inode(sb);
> +	if (!inode) {
> +		inode = ERR_PTR(-ENOMEM);
> +		goto out;
> +	}
> +	inode->i_ino = iunique(sb, EXFAT_ROOT_INO);
> +	inode_set_iversion(inode, 1);
> +	err = exfat_fill_inode(inode, info);
> +	if (err) {
> +		iput(inode);
> +		inode = ERR_PTR(err);
> +		goto out;
> +	}
> +	exfat_hash_inode(inode, i_pos);
> +	insert_inode_hash(inode);
> +out:
> +	return inode;
> +}
> +
> +void exfat_evict_inode(struct inode *inode)
> +{
> +	truncate_inode_pages(&inode->i_data, 0);
> +
> +	if (!inode->i_nlink) {
> +		i_size_write(inode, 0);
> +		mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
> +		__exfat_truncate(inode, 0);
> +		mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
> +	}
> +
> +	invalidate_inode_buffers(inode);
> +	clear_inode(inode);
> +	exfat_cache_inval_inode(inode);
> +	exfat_unhash_inode(inode);
> +}
> diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
> new file mode 100644
> index 000000000000..120a50fc494a
> --- /dev/null
> +++ b/fs/exfat/namei.c
> @@ -0,0 +1,1459 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/iversion.h>
> +#include <linux/namei.h>
> +#include <linux/slab.h>
> +#include <linux/buffer_head.h>
> +#include <linux/nls.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +static inline unsigned long exfat_d_version(struct dentry *dentry)
> +{
> +	return (unsigned long) dentry->d_fsdata;
> +}
> +
> +static inline void exfat_d_version_set(struct dentry *dentry,
> +		unsigned long version)
> +{
> +	dentry->d_fsdata = (void *) version;
> +}
> +
> +/*
> + * If new entry was created in the parent, it could create the 8.3
> + * alias (the shortname of logname).  So, the parent may have the
> + * negative-dentry which matches the created 8.3 alias.
> + *
> + * If it happened, the negative dentry isn't actually negative
> + * anymore.  So, drop it.
> + */
> +static int __exfat_revalidate_common(struct dentry *dentry)
> +{
> +	int ret = 1;
> +
> +	spin_lock(&dentry->d_lock);
> +	if (!inode_eq_iversion(d_inode(dentry->d_parent),
> +			exfat_d_version(dentry)))
> +		ret = 0;
> +	spin_unlock(&dentry->d_lock);
> +	return ret;
> +}
> +
> +static int __exfat_revalidate(struct dentry *dentry)
> +{
> +	/* This is not negative dentry. Always valid. */
> +	if (d_really_is_positive(dentry))
> +		return 1;
> +	return __exfat_revalidate_common(dentry);
> +}
> +
> +static int __exfat_revalidate_ci(struct dentry *dentry, unsigned int
> flags)
> +{
> +	/*
> +	 * This is not negative dentry. Always valid.
> +	 *
> +	 * Note, rename() to existing directory entry will have
> ->d_inode,
> +	 * and will use existing name which isn't specified name by
> user.
> +	 *
> +	 * We may be able to drop this positive dentry here. But
> dropping
> +	 * positive dentry isn't good idea. So it's unsupported like
> +	 * rename("filename", "FILENAME") for now.
> +	 */
> +	if (d_really_is_positive(dentry))
> +		return 1;
> +	/*
> +	 * Drop the negative dentry, in order to make sure to use the
> +	 * case sensitive name which is specified by user if this is
> +	 * for creation.
> +	 */
> +	if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
> +		return 0;
> +	return __exfat_revalidate_common(dentry);
> +}
> +
> +
> +/* returns the length of a struct qstr, ignoring trailing dots */
> +static unsigned int __exfat_striptail_len(unsigned int len, const
> char *name)
> +{
> +	while (len && name[len - 1] == '.')
> +		len--;
> +	return len;
> +}
> +
> +static unsigned int exfat_striptail_len(const struct qstr *qstr)
> +{
> +	return __exfat_striptail_len(qstr->len, qstr->name);
> +}
> +
> +static inline unsigned int __exfat_full_name_hash(const struct
> dentry *dentry,
> +		const char *name, unsigned int len)
> +{
> +	return full_name_hash(dentry, name, len);
> +}
> +
> +static inline unsigned long __exfat_init_name_hash(const struct
> dentry *dentry)
> +{
> +	return init_name_hash(dentry);
> +}
> +
> +/*
> + * Compute the hash for the exfat name corresponding to the dentry.
> + * Note: if the name is invalid, we leave the hash code unchanged so
> + * that the existing dentry can be used. The exfat fs routines will
> + * return ENOENT or EINVAL as appropriate.
> + */
> +static int exfat_d_hash(const struct dentry *dentry, struct qstr
> *qstr)
> +{
> +	unsigned int len = exfat_striptail_len(qstr);
> +
> +	qstr->hash = __exfat_full_name_hash(dentry, qstr->name, len);
> +	return 0;
> +}
> +
> +/*
> + * Compute the hash for the exfat name corresponding to the dentry.
> + * Note: if the name is invalid, we leave the hash code unchanged so
> + * that the existing dentry can be used. The exfat fs routines will
> + * return ENOENT or EINVAL as appropriate.
> + */
> +static int exfat_d_hashi(const struct dentry *dentry, struct qstr
> *qstr)
> +{
> +	struct nls_table *t = EXFAT_SB(dentry->d_sb)->nls_io;
> +	const unsigned char *name;
> +	unsigned int len;
> +	unsigned long hash;
> +
> +	name = qstr->name;
> +	len = exfat_striptail_len(qstr);
> +
> +	hash = __exfat_init_name_hash(dentry);
> +	while (len--)
> +		hash = partial_name_hash(nls_tolower(t, *name++),
> hash);
> +	qstr->hash = end_name_hash(hash);
> +
> +	return 0;
> +}
> +
> +/*
> + * Case sensitive compare of two exfat names.
> + */
> +static int exfat_cmp(const struct dentry *dentry, unsigned int len,
> +		const char *str, const struct qstr *name)
> +{
> +	unsigned int alen, blen;
> +
> +	/* A filename cannot end in '.' or we treat it like it has none
> */
> +	alen = exfat_striptail_len(name);
> +	blen = __exfat_striptail_len(len, str);
> +	if (alen == blen) {
> +		if (strncmp(name->name, str, alen) == 0)
> +			return 0;
> +	}
> +	return 1;
> +}
> +
> +/*
> + * Case insensitive compare of two exfat names.
> + */
> +static int exfat_cmpi(const struct dentry *dentry, unsigned int len,
> +		const char *str, const struct qstr *name)
> +{
> +	struct nls_table *t = EXFAT_SB(dentry->d_sb)->nls_io;
> +	unsigned int alen, blen;
> +
> +	/* A filename cannot end in '.' or we treat it like it has none
> */
> +	alen = exfat_striptail_len(name);
> +	blen = __exfat_striptail_len(len, str);
> +	if (alen == blen) {
> +		if (nls_strnicmp(t, name->name, str, alen) == 0)
> +			return 0;
> +	}
> +	return 1;
> +}
> +
> +static int exfat_revalidate(struct dentry *dentry, unsigned int
> flags)
> +{
> +	if (flags & LOOKUP_RCU)
> +		return -ECHILD;
> +
> +	return __exfat_revalidate(dentry);
> +}
> +
> +static int exfat_revalidate_ci(struct dentry *dentry, unsigned int
> flags)
> +{
> +	if (flags & LOOKUP_RCU)
> +		return -ECHILD;
> +
> +	return __exfat_revalidate_ci(dentry, flags);
> +}
> +
> +const struct dentry_operations exfat_dentry_ops = {
> +	.d_revalidate	= exfat_revalidate,
> +	.d_hash		= exfat_d_hash,
> +	.d_compare	= exfat_cmp,
> +};
> +
> +const struct dentry_operations exfat_ci_dentry_ops = {
> +	.d_revalidate	= exfat_revalidate_ci,
> +	.d_hash		= exfat_d_hashi,
> +	.d_compare	= exfat_cmpi,
> +};
> +
> +/* used only in search empty_slot() */
> +#define CNT_UNUSED_NOHIT        (-1)
> +#define CNT_UNUSED_HIT          (-2)
> +/* search EMPTY CONTINUOUS "num_entries" entries */
> +static int exfat_search_empty_slot(struct super_block *sb,
> +		struct exfat_hint_femp *hint_femp, struct exfat_chain
> *p_dir,
> +		int num_entries)
> +{
> +	int i, dentry, num_empty = 0;
> +	int dentries_per_clu;
> +	unsigned int type;
> +	struct exfat_chain clu;
> +	struct exfat_dentry *ep;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +
> +	dentries_per_clu = sbi->dentries_per_clu;
> +
> +	if (hint_femp->eidx != EXFAT_HINT_NONE) {
> +		dentry = hint_femp->eidx;
> +		if (num_entries <= hint_femp->count) {
> +			hint_femp->eidx = EXFAT_HINT_NONE;
> +			return dentry;
> +		}
> +
> +		exfat_chain_dup(&clu, &hint_femp->cur);
> +	} else {
> +		exfat_chain_dup(&clu, p_dir);
> +		dentry = 0;
> +	}
> +
> +	while (clu.dir != EOF_CLUSTER) {
> +		i = dentry & (dentries_per_clu - 1);
> +
> +		for (; i < dentries_per_clu; i++, dentry++) {
> +			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
> +			if (!ep)
> +				return -EIO;
> +			type = exfat_get_entry_type(ep);
> +			brelse(bh);
> +
> +			if (type == TYPE_UNUSED || type ==
> TYPE_DELETED) {
> +				num_empty++;
> +				if (hint_femp->eidx == EXFAT_HINT_NONE)
> {
> +					hint_femp->eidx = dentry;
> +					hint_femp->count =
> CNT_UNUSED_NOHIT;
> +					exfat_chain_set(&hint_femp-
> >cur,
> +						clu.dir, clu.size,
> clu.flags);
> +				}
> +
> +				if (type == TYPE_UNUSED &&
> +				    hint_femp->count != CNT_UNUSED_HIT)
> +					hint_femp->count =
> CNT_UNUSED_HIT;
> +			} else {
> +				if (hint_femp->eidx != EXFAT_HINT_NONE
> &&
> +				    hint_femp->count == CNT_UNUSED_HIT)
> {
> +					/* unused empty group means
> +					 * an empty group which
> includes
> +					 * unused dentry
> +					 */
> +					exfat_fs_error(sb,
> +						"found bogus dentry(%d)
> beyond unused empty group(%d) (start_clu : %u, cur_clu : %u)",
> +						dentry, hint_femp-
> >eidx,
> +						p_dir->dir, clu.dir);
> +					return -EIO;
> +				}
> +
> +				num_empty = 0;
> +				hint_femp->eidx = EXFAT_HINT_NONE;
> +			}
> +
> +			if (num_empty >= num_entries) {
> +				/* found and invalidate hint_femp */
> +				hint_femp->eidx = EXFAT_HINT_NONE;
> +				return (dentry - (num_entries - 1));
> +			}
> +		}
> +
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			if (--clu.size > 0)
> +				clu.dir++;
> +			else
> +				clu.dir = EOF_CLUSTER;
> +		} else {
> +			if (exfat_get_next_cluster(sb, &clu.dir))
> +				return -EIO;
> +		}
> +	}
> +
> +	return -ENOSPC;
> +}
> +
> +static int exfat_check_max_dentries(struct inode *inode)
> +{
> +	if (EXFAT_B_TO_DEN(i_size_read(inode)) >= MAX_EXFAT_DENTRIES) {
> +		/*
> +		 * exFAT spec allows a dir to grow upto 8388608(256MB)
> +		 * dentries
> +		 */
> +		return -ENOSPC;
> +	}
> +	return 0;
> +}
> +
> +/* find empty directory entry.
> + * if there isn't any empty slot, expand cluster chain.
> + */
> +int exfat_find_empty_entry(struct inode *inode, struct exfat_chain
> *p_dir,
> +		int num_entries)
> +{
> +	int dentry;
> +	unsigned int ret, last_clu;
> +	sector_t sector;
> +	loff_t size = 0;
> +	struct exfat_chain clu;
> +	struct exfat_dentry *ep = NULL;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	struct exfat_hint_femp hint_femp;
> +
> +	hint_femp.eidx = EXFAT_HINT_NONE;
> +
> +	if (ei->hint_femp.eidx != EXFAT_HINT_NONE) {
> +		memcpy(&hint_femp, &ei->hint_femp,
> +				sizeof(struct exfat_hint_femp));
> +		ei->hint_femp.eidx = EXFAT_HINT_NONE;
> +	}
> +
> +	while ((dentry = exfat_search_empty_slot(sb, &hint_femp, p_dir,
> +					num_entries)) < 0) {
> +		if (dentry == -EIO)
> +			break;
> +
> +		if (exfat_check_max_dentries(inode))
> +			return -ENOSPC;
> +
> +		/* we trust p_dir->size regardless of FAT type */
> +		if (exfat_find_last_cluster(sb, p_dir, &last_clu))
> +			return -EIO;
> +
> +		/*
> +		 * Allocate new cluster to this directory
> +		 */
> +		exfat_chain_set(&clu, last_clu + 1, 0, p_dir->flags);
> +
> +		/* allocate a cluster */
> +		ret = exfat_alloc_cluster(inode, 1, &clu);
> +		if (ret)
> +			return ret;
> +
> +		if (exfat_zeroed_cluster(inode, clu.dir))
> +			return -EIO;
> +
> +		/* append to the FAT chain */
> +		if (clu.flags != p_dir->flags) {
> +			/* no-fat-chain bit is disabled,
> +			 * so fat-chain should be synced with alloc-
> bitmap
> +			 */
> +			exfat_chain_cont_cluster(sb, p_dir->dir, p_dir-
> >size);
> +			p_dir->flags = ALLOC_FAT_CHAIN;
> +			hint_femp.cur.flags = ALLOC_FAT_CHAIN;
> +		}
> +
> +		if (clu.flags == ALLOC_FAT_CHAIN)
> +			if (exfat_ent_set(sb, last_clu, clu.dir))
> +				return -EIO;
> +
> +		if (hint_femp.eidx == EXFAT_HINT_NONE) {
> +			/* the special case that new dentry
> +			 * should be allocated from the start of new
> cluster
> +			 */
> +			hint_femp.eidx = EXFAT_B_TO_DEN_IDX(p_dir-
> >size, sbi);
> +			hint_femp.count = sbi->dentries_per_clu;
> +
> +			exfat_chain_set(&hint_femp.cur, clu.dir, 0,
> clu.flags);
> +		}
> +		hint_femp.cur.size++;
> +		p_dir->size++;
> +		size = EXFAT_CLU_TO_B(p_dir->size, sbi);
> +
> +		/* update the directory entry */
> +		if (p_dir->dir != sbi->root_dir) {
> +			struct buffer_head *bh;
> +
> +			ep = exfat_get_dentry(sb,
> +				&(ei->dir), ei->entry + 1, &bh,
> &sector);
> +			if (!ep)
> +				return -EIO;
> +
> +			ep->stream_valid_size = cpu_to_le64(size);
> +			ep->stream_size = ep->stream_valid_size;
> +			ep->stream_flags = p_dir->flags;
> +			exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
> +			brelse(bh);
> +			if (update_dir_chksum(inode, &(ei->dir), ei-
> >entry))
> +				return -EIO;
> +		}
> +
> +		/* directory inode should be updated in here */
> +		i_size_write(inode, size);
> +		EXFAT_I(inode)->i_size_ondisk += sbi->cluster_size;
> +		EXFAT_I(inode)->i_size_aligned += sbi->cluster_size;
> +		EXFAT_I(inode)->flags = p_dir->flags;
> +		inode->i_blocks += 1 << sbi->sect_per_clus_bits;
> +	}
> +
> +	return dentry;
> +}
> +
> +/*
> + * Name Resolution Functions :
> + * Zero if it was successful; otherwise nonzero.
> + */
> +static int __exfat_resolve_path(struct inode *inode, const unsigned
> char *path,
> +		struct exfat_chain *p_dir, struct exfat_uni_name
> *p_uniname,
> +		int lookup)
> +{
> +	int namelen;
> +	int lossy = NLS_NAME_NO_LOSSY;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +
> +	/* DOT and DOTDOT are handled by VFS layer */
> +
> +	/* strip all trailing spaces */
> +	/* DO NOTHING : Is needed? */
> +
> +	/* strip all trailing periods */
> +	namelen = __exfat_striptail_len(strlen(path), path);
> +	if (!namelen)
> +		return -ENOENT;
> +
> +	/* the limitation of linux? */
> +	if (strlen(path) > (MAX_NAME_LENGTH * MAX_CHARSET_SIZE))
> +		return -ENAMETOOLONG;
> +
> +	/*
> +	 * strip all leading spaces :
> +	 * "MS windows 7" supports leading spaces.
> +	 * So we should skip this preprocessing for compatibility.
> +	 */
> +
> +	/* file name conversion :
> +	 * If lookup case, we allow bad-name for compatibility.
> +	 */
> +	namelen = exfat_nls_vfsname_to_uni16s(sb, path, namelen,
> p_uniname,
> +			&lossy);
> +	if (namelen < 0)
> +		return namelen; /* return error value */
> +
> +	if ((lossy && !lookup) || !namelen)
> +		return -EINVAL;
> +
> +	exfat_chain_set(p_dir, ei->start_clu,
> +		EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
> +
> +	return 0;
> +}
> +
> +static inline int exfat_resolve_path(struct inode *inode,
> +		const unsigned char *path, struct exfat_chain *dir,
> +		struct exfat_uni_name *uni)
> +{
> +	return __exfat_resolve_path(inode, path, dir, uni, 0);
> +}
> +
> +static inline int exfat_resolve_path_for_lookup(struct inode *inode,
> +		const unsigned char *path, struct exfat_chain *dir,
> +		struct exfat_uni_name *uni)
> +{
> +	return __exfat_resolve_path(inode, path, dir, uni, 1);
> +}
> +
> +static inline loff_t exfat_make_i_pos(struct exfat_dir_entry *info)
> +{
> +	return ((loff_t) info->dir.dir << 32) | (info->entry &
> 0xffffffff);
> +}
> +
> +static int exfat_add_entry(struct inode *inode, const char *path,
> +		struct exfat_chain *p_dir, unsigned int type,
> +		struct exfat_dir_entry *info)
> +{
> +	int ret, dentry, num_entries;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_uni_name uniname;
> +	struct exfat_chain clu;
> +	int clu_size = 0;
> +	unsigned int start_clu = FREE_CLUSTER;
> +
> +	ret = exfat_resolve_path(inode, path, p_dir, &uniname);
> +	if (ret)
> +		goto out;
> +
> +	num_entries = exfat_get_num_entries(&uniname);
> +	if (num_entries < 0) {
> +		ret = num_entries;
> +		goto out;
> +	}
> +
> +	/* exfat_find_empty_entry must be called before alloc_cluster()
> */
> +	dentry = exfat_find_empty_entry(inode, p_dir, num_entries);
> +	if (dentry < 0) {
> +		ret = dentry; /* -EIO or -ENOSPC */
> +		goto out;
> +	}
> +
> +	if (type == TYPE_DIR) {
> +		ret = exfat_alloc_new_dir(inode, &clu);
> +		if (ret)
> +			goto out;
> +		start_clu = clu.dir;
> +		clu_size = sbi->cluster_size;
> +	}
> +
> +	/* update the directory entry */
> +	/* fill the dos name directory entry information of the created
> file.
> +	 * the first cluster is not determined yet. (0)
> +	 */
> +	ret = exfat_init_dir_entry(inode, p_dir, dentry, type,
> +		start_clu, clu_size);
> +	if (ret)
> +		goto out;
> +
> +	ret = exfat_init_ext_entry(inode, p_dir, dentry, num_entries,
> &uniname);
> +	if (ret)
> +		goto out;
> +
> +	memcpy(&info->dir, p_dir, sizeof(struct exfat_chain));
> +	info->entry = dentry;
> +	info->flags = ALLOC_NO_FAT_CHAIN;
> +	info->type = type;
> +
> +	if (type == TYPE_FILE) {
> +		info->attr = ATTR_ARCHIVE;
> +		info->start_clu = EOF_CLUSTER;
> +		info->size = 0;
> +		info->num_subdirs = 0;
> +	} else {
> +		int count;
> +		struct exfat_chain cdir;
> +
> +		info->attr = ATTR_SUBDIR;
> +		info->start_clu = start_clu;
> +		info->size = clu_size;
> +
> +		exfat_chain_set(&cdir, info->start_clu,
> +			EXFAT_B_TO_CLU(info->size, sbi), info->flags);
> +		count = exfat_count_dir_entries(sb, &cdir);
> +		if (count < 0)
> +			return -EIO;
> +		info->num_subdirs = count + EXFAT_MIN_SUBDIR;
> +	}
> +	memset(&info->create_timestamp, 0,
> +			sizeof(struct exfat_date_time));
> +	memset(&info->modify_timestamp, 0,
> +			sizeof(struct exfat_date_time));
> +	memset(&info->access_timestamp, 0,
> +			sizeof(struct exfat_date_time));
> +out:
> +	return ret;
> +}
> +
> +static int exfat_create(struct inode *dir, struct dentry *dentry,
> umode_t mode,
> +		bool excl)
> +{
> +	struct super_block *sb = dir->i_sb;
> +	struct inode *inode;
> +	struct exfat_chain cdir;
> +	struct exfat_dir_entry info;
> +	loff_t i_pos;
> +	int err;
> +
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +	err = exfat_add_entry(dir, dentry->d_name.name, &cdir,
> TYPE_FILE,
> +		&info);
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +	if (err)
> +		goto unlock;
> +
> +	inode_inc_iversion(dir);
> +	dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
> +	if (IS_DIRSYNC(dir))
> +		exfat_sync_inode(dir);
> +	else
> +		mark_inode_dirty(dir);
> +
> +	i_pos = exfat_make_i_pos(&info);
> +	inode = exfat_build_inode(sb, &info, i_pos);
> +	if (IS_ERR(inode))
> +		goto unlock;
> +
> +	inode_inc_iversion(inode);
> +	inode->i_mtime = inode->i_atime = inode->i_ctime =
> current_time(inode);
> +	/* timestamp is already written, so mark_inode_dirty() is
> unneeded. */
> +
> +	d_instantiate(dentry, inode);
> +unlock:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	return err;
> +}
> +
> +/* lookup a file */
> +static int exfat_find(struct inode *dir, struct qstr *qname,
> +		struct exfat_dir_entry *info)
> +{
> +	int ret, dentry, num_entries, count;
> +	struct exfat_chain cdir;
> +	struct exfat_uni_name uni_name;
> +	struct exfat_dentry *ep, *ep2;
> +	struct exfat_entry_set_cache *es = NULL;
> +	struct super_block *sb = dir->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(dir);
> +	struct exfat_timestamp tm;
> +
> +	if (qname->len == 0)
> +		return -ENOENT;
> +
> +	/* check the validity of directory name in the given pathname
> */
> +	ret = exfat_resolve_path_for_lookup(dir, qname->name, &cdir,
> &uni_name);
> +	if (ret)
> +		return ret;
> +
> +	num_entries = exfat_get_num_entries(&uni_name);
> +	if (num_entries < 0)
> +		return num_entries;
> +
> +	/* check the validation of hint_stat and initialize it if
> required */
> +	if (ei->version != (inode_peek_iversion_raw(dir) & 0xffffffff))
> {
> +		ei->hint_stat.clu = cdir.dir;
> +		ei->hint_stat.eidx = 0;
> +		ei->version = (inode_peek_iversion_raw(dir) &
> 0xffffffff);
> +		ei->hint_femp.eidx = EXFAT_HINT_NONE;
> +	}
> +
> +	/* search the file name for directories */
> +	dentry = exfat_find_dir_entry(sb, ei, &cdir, &uni_name,
> +			num_entries, TYPE_ALL);
> +
> +	if ((dentry < 0) && (dentry != -EEXIST))
> +		return dentry; /* -error value */
> +
> +	memcpy(&info->dir, &cdir.dir, sizeof(struct exfat_chain));
> +	info->entry = dentry;
> +	info->num_subdirs = 0;
> +
> +	/* root directory itself */
> +	if (unlikely(dentry == -EEXIST)) {
> +		int num_clu = 0;
> +
> +		info->type = TYPE_DIR;
> +		info->attr = ATTR_SUBDIR;
> +		info->flags = ALLOC_FAT_CHAIN;
> +		info->start_clu = sbi->root_dir;
> +		memset(&info->create_timestamp, 0,
> +				sizeof(struct exfat_date_time));
> +		memset(&info->modify_timestamp, 0,
> +				sizeof(struct exfat_date_time));
> +		memset(&info->access_timestamp, 0,
> +				sizeof(struct exfat_date_time));
> +
> +		exfat_chain_set(&cdir, sbi->root_dir, 0,
> ALLOC_FAT_CHAIN);
> +		if (exfat_count_num_clusters(sb, &cdir, &num_clu))
> +			return -EIO;
> +		info->size = num_clu << sbi->cluster_size_bits;
> +
> +		count = exfat_count_dir_entries(sb, &cdir);
> +		if (count < 0)
> +			return -EIO;
> +
> +		info->num_subdirs = count;
> +	} else {
> +		es = exfat_get_dentry_set(sb, &cdir, dentry,
> ES_2_ENTRIES, &ep);
> +		if (!es)
> +			return -EIO;
> +		ep2 = ep + 1;


Ditto. The ep2 could point out on the garbage!!!

Thanks,
Viacheslav Dubeyko.


> +
> +		info->type = exfat_get_entry_type(ep);
> +		info->attr = le16_to_cpu(ep->file_attr);
> +		info->size = le64_to_cpu(ep2->stream_valid_size);
> +		if ((info->type == TYPE_FILE) && (info->size == 0)) {
> +			info->flags = ALLOC_NO_FAT_CHAIN;
> +			info->start_clu = EOF_CLUSTER;
> +		} else {
> +			info->flags = ep2->stream_flags;
> +			info->start_clu = le32_to_cpu(ep2-
> >stream_start_clu);
> +		}
> +
> +		if (ei->start_clu == FREE_CLUSTER) {
> +			exfat_fs_error(sb,
> +				"non-zero size file starts with zero
> cluster (size : %llu, p_dir : %u, entry : 0x%08x)",
> +				i_size_read(dir), ei->dir.dir, ei-
> >entry);
> +			return -EIO;
> +		}
> +
> +		exfat_get_entry_time(ep, &tm, TM_CREATE);
> +		info->create_timestamp.year = tm.year;
> +		info->create_timestamp.month = tm.mon;
> +		info->create_timestamp.day = tm.day;
> +		info->create_timestamp.hour = tm.hour;
> +		info->create_timestamp.minute = tm.min;
> +		info->create_timestamp.second = tm.sec;
> +		info->create_timestamp.milli_second = 0;
> +
> +		exfat_get_entry_time(ep, &tm, TM_MODIFY);
> +		info->modify_timestamp.year = tm.year;
> +		info->modify_timestamp.month = tm.mon;
> +		info->modify_timestamp.day = tm.day;
> +		info->modify_timestamp.hour = tm.hour;
> +		info->modify_timestamp.minute = tm.min;
> +		info->modify_timestamp.second = tm.sec;
> +		info->modify_timestamp.milli_second = 0;
> +
> +		memset(&info->access_timestamp, 0,
> +				sizeof(struct exfat_date_time));
> +		kfree(es);
> +
> +		if (info->type == TYPE_DIR) {
> +			exfat_chain_set(&cdir, info->start_clu,
> +				EXFAT_B_TO_CLU(info->size, sbi), info-
> >flags);
> +			count = exfat_count_dir_entries(sb, &cdir);
> +			if (count < 0)
> +				return -EIO;
> +
> +			info->num_subdirs = count + EXFAT_MIN_SUBDIR;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int exfat_d_anon_disconn(struct dentry *dentry)
> +{
> +	return IS_ROOT(dentry) && (dentry->d_flags &
> DCACHE_DISCONNECTED);
> +}
> +
> +static struct dentry *exfat_lookup(struct inode *dir, struct dentry
> *dentry,
> +		unsigned int flags)
> +{
> +	struct super_block *sb = dir->i_sb;
> +	struct inode *inode;
> +	struct dentry *alias;
> +	struct exfat_dir_entry info;
> +	int err;
> +	loff_t i_pos;
> +	mode_t i_mode;
> +
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	err = exfat_find(dir, &dentry->d_name, &info);
> +	if (err) {
> +		if (err == -ENOENT) {
> +			inode = NULL;
> +			goto out;
> +		}
> +		goto unlock;
> +	}
> +
> +	i_pos = exfat_make_i_pos(&info);
> +	inode = exfat_build_inode(sb, &info, i_pos);
> +	if (IS_ERR(inode)) {
> +		err = PTR_ERR(inode);
> +		goto unlock;
> +	}
> +
> +	i_mode = inode->i_mode;
> +	alias = d_find_alias(inode);
> +
> +	/*
> +	 * Checking "alias->d_parent == dentry->d_parent" to make sure
> +	 * FS is not corrupted (especially double linked dir).
> +	 */
> +	if (alias && alias->d_parent == dentry->d_parent &&
> +			!exfat_d_anon_disconn(alias)) {
> +
> +		/*
> +		 * Unhashed alias is able to exist because of
> revalidate()
> +		 * called by lookup_fast. You can easily make this
> status
> +		 * by calling create and lookup concurrently
> +		 * In such case, we reuse an alias instead of new
> dentry
> +		 */
> +		if (d_unhashed(alias)) {
> +			WARN_ON(alias->d_name.hash_len !=
> +				dentry->d_name.hash_len);
> +			exfat_msg(sb, KERN_INFO,
> +				"rehashed a dentry(%p) in read lookup",
> alias);
> +			d_drop(dentry);
> +			d_rehash(alias);
> +		} else if (!S_ISDIR(i_mode)) {
> +			/*
> +			 * This inode has non anonymous-
> DCACHE_DISCONNECTED
> +			 * dentry. This means, the user did ->lookup()
> by an
> +			 * another name (longname vs 8.3 alias of it)
> in past.
> +			 *
> +			 * Switch to new one for reason of locality if
> possible.
> +			 */
> +			d_move(alias, dentry);
> +		}
> +		iput(inode);
> +		mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +		return alias;
> +	}
> +	dput(alias);
> +out:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	if (!inode)
> +		exfat_d_version_set(dentry, inode_query_iversion(dir));
> +
> +	return d_splice_alias(inode, dentry);
> +unlock:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	return ERR_PTR(err);
> +}
> +
> +/* remove an entry, BUT don't truncate */
> +static int exfat_unlink(struct inode *dir, struct dentry *dentry)
> +{
> +	struct exfat_chain cdir;
> +	struct exfat_dentry *ep;
> +	struct super_block *sb = dir->i_sb;
> +	struct inode *inode = dentry->d_inode;
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	struct buffer_head *bh;
> +	sector_t sector;
> +	int num_entries, entry, err = 0;
> +
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	exfat_chain_dup(&cdir, &ei->dir);
> +	entry = ei->entry;
> +	if (ei->dir.dir == DIR_DELETED) {
> +		exfat_msg(sb, KERN_ERR, "abnormal access to deleted
> dentry");
> +		err = -ENOENT;
> +		goto unlock;
> +	}
> +
> +	ep = exfat_get_dentry(sb, &cdir, entry, &bh, &sector);
> +	if (!ep) {
> +		err = -EIO;
> +		goto unlock;
> +	}
> +	num_entries = exfat_count_ext_entries(sb, &cdir, entry, ep);
> +	if (num_entries < 0) {
> +		err = -EIO;
> +		brelse(bh);
> +		goto unlock;
> +	}
> +	num_entries++;
> +	brelse(bh);
> +
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +	/* update the directory entry */
> +	if (exfat_remove_entries(dir, &cdir, entry, 0, num_entries)) {
> +		err = -EIO;
> +		goto unlock;
> +	}
> +
> +	/* This doesn't modify ei */
> +	ei->dir.dir = DIR_DELETED;
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +
> +	inode_inc_iversion(dir);
> +	dir->i_mtime = dir->i_atime = current_time(dir);
> +	if (IS_DIRSYNC(dir))
> +		exfat_sync_inode(dir);
> +	else
> +		mark_inode_dirty(dir);
> +
> +	clear_nlink(inode);
> +	inode->i_mtime = inode->i_atime = current_time(inode);
> +	exfat_unhash_inode(inode);
> +	exfat_d_version_set(dentry, inode_query_iversion(dir));
> +unlock:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	return err;
> +}
> +
> +static int exfat_mkdir(struct inode *dir, struct dentry *dentry,
> umode_t mode)
> +{
> +	struct super_block *sb = dir->i_sb;
> +	struct inode *inode;
> +	struct exfat_dir_entry info;
> +	struct exfat_chain cdir;
> +	loff_t i_pos;
> +	int err;
> +
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +	err = exfat_add_entry(dir, dentry->d_name.name, &cdir,
> TYPE_DIR,
> +		&info);
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +	if (err)
> +		goto unlock;
> +
> +	inode_inc_iversion(dir);
> +	dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
> +	if (IS_DIRSYNC(dir))
> +		exfat_sync_inode(dir);
> +	else
> +		mark_inode_dirty(dir);
> +	inc_nlink(dir);
> +
> +	i_pos = exfat_make_i_pos(&info);
> +	inode = exfat_build_inode(sb, &info, i_pos);
> +	if (IS_ERR(inode)) {
> +		err = PTR_ERR(inode);
> +		goto unlock;
> +	}
> +
> +	inode_inc_iversion(inode);
> +	inode->i_mtime = inode->i_atime = inode->i_ctime =
> current_time(inode);
> +	/* timestamp is already written, so mark_inode_dirty() is
> unneeded. */
> +
> +	d_instantiate(dentry, inode);
> +
> +unlock:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	return err;
> +}
> +
> +static int exfat_check_dir_empty(struct super_block *sb,
> +		struct exfat_chain *p_dir)
> +{
> +	int i, dentries_per_clu;
> +	unsigned int type;
> +	struct exfat_chain clu;
> +	struct exfat_dentry *ep;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +
> +	dentries_per_clu = sbi->dentries_per_clu;
> +
> +	exfat_chain_dup(&clu, p_dir);
> +
> +	while (clu.dir != EOF_CLUSTER) {
> +		for (i = 0; i < dentries_per_clu; i++) {
> +			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
> +			if (!ep)
> +				return -EIO;
> +			type = exfat_get_entry_type(ep);
> +			brelse(bh);
> +			if (type == TYPE_UNUSED)
> +				return 0;
> +
> +			if (type != TYPE_FILE && type != TYPE_DIR)
> +				continue;
> +
> +			return -ENOTEMPTY;
> +		}
> +
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			if (--clu.size > 0)
> +				clu.dir++;
> +			else
> +				clu.dir = EOF_CLUSTER;
> +		} else {
> +			if (exfat_get_next_cluster(sb, &(clu.dir)))
> +				return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
> +{
> +	struct inode *inode = dentry->d_inode;
> +	struct exfat_dentry *ep;
> +	struct exfat_chain cdir, clu_to_free;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	struct buffer_head *bh;
> +	sector_t sector;
> +	int num_entries, entry, err;
> +
> +	mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
> +
> +	exfat_chain_dup(&cdir, &ei->dir);
> +	entry = ei->entry;
> +
> +	if (ei->dir.dir == DIR_DELETED) {
> +		exfat_msg(sb, KERN_ERR, "abnormal access to deleted
> dentry");
> +		err = -ENOENT;
> +		goto unlock;
> +	}
> +
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +	exfat_chain_set(&clu_to_free, ei->start_clu,
> +		EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi), ei-
> >flags);
> +
> +	err = exfat_check_dir_empty(sb, &clu_to_free);
> +	if (err) {
> +		if (err == -EIO)
> +			exfat_msg(sb, KERN_ERR,
> +				"failed to exfat_check_dir_empty :
> err(%d)",
> +				err);
> +		goto unlock;
> +	}
> +
> +	ep = exfat_get_dentry(sb, &cdir, entry, &bh, &sector);
> +	if (!ep) {
> +		err = -EIO;
> +		goto unlock;
> +	}
> +
> +	num_entries = exfat_count_ext_entries(sb, &cdir, entry, ep);
> +	if (num_entries < 0) {
> +		err = -EIO;
> +		brelse(bh);
> +		goto unlock;
> +	}
> +	num_entries++;
> +	brelse(bh);
> +
> +	err = exfat_remove_entries(dir, &cdir, entry, 0, num_entries);
> +	if (err) {
> +		exfat_msg(sb, KERN_ERR,
> +				"failed to exfat_remove_entries :
> err(%d)",
> +				err);
> +		goto unlock;
> +	}
> +	ei->dir.dir = DIR_DELETED;
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +
> +	inode_inc_iversion(dir);
> +	dir->i_mtime = dir->i_atime = current_time(dir);
> +	if (IS_DIRSYNC(dir))
> +		exfat_sync_inode(dir);
> +	else
> +		mark_inode_dirty(dir);
> +	drop_nlink(dir);
> +
> +	clear_nlink(inode);
> +	inode->i_mtime = inode->i_atime = current_time(inode);
> +	exfat_unhash_inode(inode);
> +	exfat_d_version_set(dentry, inode_query_iversion(dir));
> +unlock:
> +	mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
> +	return err;
> +}
> +
> +static int exfat_rename_file(struct inode *inode, struct exfat_chain
> *p_dir,
> +		int oldentry, struct exfat_uni_name *p_uniname,
> +		struct exfat_inode_info *ei)
> +{
> +	int ret, num_old_entries, num_new_entries;
> +	sector_t sector_old, sector_new;
> +	struct exfat_dentry *epold, *epnew;
> +	struct super_block *sb = inode->i_sb;
> +	struct buffer_head *new_bh, *old_bh;
> +	int sync = IS_DIRSYNC(inode);
> +
> +	epold = exfat_get_dentry(sb, p_dir, oldentry, &old_bh,
> &sector_old);
> +	if (!epold)
> +		return -EIO;
> +
> +	num_old_entries = exfat_count_ext_entries(sb, p_dir, oldentry,
> epold);
> +	if (num_old_entries < 0)
> +		return -EIO;
> +	num_old_entries++;
> +
> +	num_new_entries = exfat_get_num_entries(p_uniname);
> +	if (num_new_entries < 0)
> +		return num_new_entries;
> +
> +	if (num_old_entries < num_new_entries) {
> +		int newentry;
> +
> +		newentry =
> +			exfat_find_empty_entry(inode, p_dir,
> num_new_entries);
> +		if (newentry < 0)
> +			return newentry; /* -EIO or -ENOSPC */
> +
> +		epnew = exfat_get_dentry(sb, p_dir, newentry, &new_bh,
> +			&sector_new);
> +		if (!epnew)
> +			return -EIO;
> +
> +		memcpy(epnew, epold, DENTRY_SIZE);
> +		if (exfat_get_entry_type(epnew) == TYPE_FILE) {
> +			epnew->file_attr |= ATTR_ARCHIVE_LE;
> +			ei->attr |= ATTR_ARCHIVE;
> +		}
> +		exfat_update_bh(sb, new_bh, sync);
> +		brelse(old_bh);
> +		brelse(new_bh);
> +
> +		epold = exfat_get_dentry(sb, p_dir, oldentry + 1,
> &old_bh,
> +			&sector_old);
> +		epnew = exfat_get_dentry(sb, p_dir, newentry + 1,
> &new_bh,
> +			&sector_new);
> +		if (!epold || !epnew)
> +			return -EIO;
> +
> +		memcpy(epnew, epold, DENTRY_SIZE);
> +		exfat_update_bh(sb, new_bh, sync);
> +		brelse(old_bh);
> +		brelse(new_bh);
> +
> +		ret = exfat_init_ext_entry(inode, p_dir, newentry,
> +			num_new_entries, p_uniname);
> +		if (ret)
> +			return ret;
> +
> +		exfat_remove_entries(inode, p_dir, oldentry, 0,
> +			num_old_entries);
> +		ei->entry = newentry;
> +	} else {
> +		if (exfat_get_entry_type(epold) == TYPE_FILE) {
> +			epold->file_attr |= ATTR_ARCHIVE_LE;
> +			ei->attr |= ATTR_ARCHIVE;
> +		}
> +		exfat_update_bh(sb, old_bh, sync);
> +		brelse(old_bh);
> +		ret = exfat_init_ext_entry(inode, p_dir, oldentry,
> +			num_new_entries, p_uniname);
> +		if (ret)
> +			return ret;
> +
> +		exfat_remove_entries(inode, p_dir, oldentry,
> num_new_entries,
> +			num_old_entries);
> +	}
> +	return 0;
> +}
> +
> +static int exfat_move_file(struct inode *inode, struct exfat_chain
> *p_olddir,
> +		int oldentry, struct exfat_chain *p_newdir,
> +		struct exfat_uni_name *p_uniname, struct
> exfat_inode_info *ei)
> +{
> +	int ret, newentry, num_new_entries, num_old_entries;
> +	sector_t sector_mov, sector_new;
> +	struct exfat_dentry *epmov, *epnew;
> +	struct super_block *sb = inode->i_sb;
> +	struct buffer_head *mov_bh, *new_bh;
> +
> +	epmov = exfat_get_dentry(sb, p_olddir, oldentry, &mov_bh,
> &sector_mov);
> +	if (!epmov)
> +		return -EIO;
> +
> +	/* check if the source and target directory is the same */
> +	if (exfat_get_entry_type(epmov) == TYPE_DIR &&
> +	    le32_to_cpu(epmov->stream_start_clu) == p_newdir->dir)
> +		return -EINVAL;
> +
> +	num_old_entries = exfat_count_ext_entries(sb, p_olddir,
> oldentry,
> +		epmov);
> +	if (num_old_entries < 0)
> +		return -EIO;
> +	num_old_entries++;
> +
> +	num_new_entries = exfat_get_num_entries(p_uniname);
> +	if (num_new_entries < 0)
> +		return num_new_entries;
> +
> +	newentry = exfat_find_empty_entry(inode, p_newdir,
> num_new_entries);
> +	if (newentry < 0)
> +		return newentry; /* -EIO or -ENOSPC */
> +
> +	epnew = exfat_get_dentry(sb, p_newdir, newentry, &new_bh,
> &sector_new);
> +	if (!epnew)
> +		return -EIO;
> +
> +	memcpy(epnew, epmov, DENTRY_SIZE);
> +	if (exfat_get_entry_type(epnew) == TYPE_FILE) {
> +		epnew->file_attr |= ATTR_ARCHIVE_LE;
> +		ei->attr |= ATTR_ARCHIVE;
> +	}
> +	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
> +	brelse(mov_bh);
> +	brelse(new_bh);
> +
> +	epmov = exfat_get_dentry(sb, p_olddir, oldentry + 1, &mov_bh,
> +		&sector_mov);
> +	epnew = exfat_get_dentry(sb, p_newdir, newentry + 1, &new_bh,
> +		&sector_new);
> +	if (!epmov || !epnew)
> +		return -EIO;
> +
> +	memcpy(epnew, epmov, DENTRY_SIZE);
> +	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
> +	brelse(mov_bh);
> +	brelse(new_bh);
> +
> +	ret = exfat_init_ext_entry(inode, p_newdir, newentry,
> num_new_entries,
> +		p_uniname);
> +	if (ret)
> +		return ret;
> +
> +	exfat_remove_entries(inode, p_olddir, oldentry, 0,
> num_old_entries);
> +
> +	exfat_chain_set(&ei->dir, p_newdir->dir, p_newdir->size,
> +		p_newdir->flags);
> +
> +	ei->entry = newentry;
> +	return 0;
> +}
> +
> +static void exfat_update_parent_info(struct exfat_inode_info *ei,
> +		struct inode *parent_inode)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(parent_inode->i_sb);
> +	struct exfat_inode_info *parent_ei = EXFAT_I(parent_inode);
> +	loff_t parent_isize = i_size_read(parent_inode);
> +
> +	/*
> +	 * the problem that struct exfat_inode_info caches wrong parent
> info.
> +	 *
> +	 * because of flag-mismatch of ei->dir,
> +	 * there is abnormal traversing cluster chain.
> +	 */
> +	if (unlikely(parent_ei->flags != ei->dir.flags ||
> +		     parent_isize != EXFAT_CLU_TO_B(ei->dir.size, sbi)
> ||
> +		     parent_ei->start_clu != ei->dir.dir)) {
> +		exfat_chain_set(&ei->dir, parent_ei->start_clu,
> +			EXFAT_B_TO_CLU_ROUND_UP(parent_isize, sbi),
> +			parent_ei->flags);
> +	}
> +}
> +
> +/* rename or move a old file into a new file */
> +static int __exfat_rename(struct inode *old_parent_inode,
> +		struct exfat_inode_info *ei, struct inode
> *new_parent_inode,
> +		struct dentry *new_dentry)
> +{
> +	int ret;
> +	int dentry;
> +	struct exfat_chain olddir, newdir;
> +	struct exfat_chain *p_dir = NULL;
> +	struct exfat_uni_name uni_name;
> +	struct exfat_dentry *ep;
> +	struct super_block *sb = old_parent_inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	const unsigned char *new_path = new_dentry->d_name.name;
> +	struct inode *new_inode = new_dentry->d_inode;
> +	int num_entries;
> +	struct exfat_inode_info *new_ei = NULL;
> +	unsigned int new_entry_type = TYPE_UNUSED;
> +	int new_entry = 0;
> +	struct buffer_head *old_bh, *new_bh = NULL;
> +
> +	/* check the validity of pointer parameters */
> +	if (new_path == NULL || strlen(new_path) == 0)
> +		return -EINVAL;
> +
> +	if (ei->dir.dir == DIR_DELETED) {
> +		exfat_msg(sb, KERN_ERR,
> +				"abnormal access to deleted source
> dentry");
> +		return -ENOENT;
> +	}
> +
> +	exfat_update_parent_info(ei, old_parent_inode);
> +
> +	exfat_chain_dup(&olddir, &ei->dir);
> +	dentry = ei->entry;
> +
> +	ep = exfat_get_dentry(sb, &olddir, dentry, &old_bh, NULL);
> +	if (!ep) {
> +		ret = -EIO;
> +		goto out;
> +	}
> +	brelse(old_bh);
> +
> +	/* check whether new dir is existing directory and empty */
> +	if (new_inode) {
> +		ret = -EIO;
> +		new_ei = EXFAT_I(new_inode);
> +
> +		if (new_ei->dir.dir == DIR_DELETED) {
> +			exfat_msg(sb, KERN_ERR,
> +				"abnormal access to deleted target
> dentry");
> +			goto out;
> +		}
> +
> +		exfat_update_parent_info(new_ei, new_parent_inode);
> +
> +		p_dir = &(new_ei->dir);
> +		new_entry = new_ei->entry;
> +		ep = exfat_get_dentry(sb, p_dir, new_entry, &new_bh,
> NULL);
> +		if (!ep)
> +			goto out;
> +
> +		new_entry_type = exfat_get_entry_type(ep);
> +		brelse(new_bh);
> +
> +		/* if new_inode exists, update ei */
> +		if (new_entry_type == TYPE_DIR) {
> +			struct exfat_chain new_clu;
> +
> +			new_clu.dir = new_ei->start_clu;
> +			new_clu.size =
> +				EXFAT_B_TO_CLU_ROUND_UP(i_size_read(new
> _inode),
> +				sbi);
> +			new_clu.flags = new_ei->flags;
> +
> +			ret = exfat_check_dir_empty(sb, &new_clu);
> +			if (ret)
> +				goto out;
> +		}
> +	}
> +
> +	/* check the validity of directory name in the given new
> pathname */
> +	ret = exfat_resolve_path(new_parent_inode, new_path, &newdir,
> +			&uni_name);
> +	if (ret)
> +		goto out;
> +
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +
> +	if (olddir.dir == newdir.dir)
> +		ret = exfat_rename_file(new_parent_inode, &olddir,
> dentry,
> +				&uni_name, ei);
> +	else
> +		ret = exfat_move_file(new_parent_inode, &olddir,
> dentry,
> +				&newdir, &uni_name, ei);
> +
> +	if (!ret && new_inode) {
> +		/* delete entries of new_dir */
> +		ep = exfat_get_dentry(sb, p_dir, new_entry, &new_bh,
> NULL);
> +		if (!ep) {
> +			ret = -EIO;
> +			goto del_out;
> +		}
> +
> +		num_entries = exfat_count_ext_entries(sb, p_dir,
> new_entry, ep);
> +		if (num_entries < 0) {
> +			ret = -EIO;
> +			goto del_out;
> +		}
> +		brelse(new_bh);
> +
> +		if (exfat_remove_entries(new_inode, p_dir, new_entry,
> 0,
> +				num_entries + 1)) {
> +			ret = -EIO;
> +			goto del_out;
> +		}
> +
> +		/* Free the clusters if new_inode is a dir(as if
> exfat_rmdir) */
> +		if (new_entry_type == TYPE_DIR) {
> +			/* new_ei, new_clu_to_free */
> +			struct exfat_chain new_clu_to_free;
> +
> +			exfat_chain_set(&new_clu_to_free, new_ei-
> >start_clu,
> +				EXFAT_B_TO_CLU_ROUND_UP(i_size_read(new
> _inode),
> +				sbi), new_ei->flags);
> +
> +			if (exfat_free_cluster(new_inode,
> &new_clu_to_free)) {
> +				/* just set I/O error only */
> +				ret = -EIO;
> +			}
> +
> +			i_size_write(new_inode, 0);
> +			new_ei->start_clu = EOF_CLUSTER;
> +			new_ei->flags = ALLOC_NO_FAT_CHAIN;
> +		}
> +del_out:
> +		/* Update new_inode ei
> +		 * Prevent syncing removed new_inode
> +		 * (new_ei is already initialized above code ("if
> (new_inode)")
> +		 */
> +		new_ei->dir.dir = DIR_DELETED;
> +	}
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +out:
> +	return ret;
> +}
> +
> +static int exfat_rename(struct inode *old_dir, struct dentry
> *old_dentry,
> +		struct inode *new_dir, struct dentry *new_dentry,
> +		unsigned int flags)
> +{
> +	struct inode *old_inode, *new_inode;
> +	struct super_block *sb = old_dir->i_sb;
> +	loff_t i_pos;
> +	int err;
> +
> +	/*
> +	 * The VFS already checks for existence, so for local
> filesystems
> +	 * the RENAME_NOREPLACE implementation is equivalent to plain
> rename.
> +	 * Don't support any other flags
> +	 */
> +	if (flags & ~RENAME_NOREPLACE)
> +		return -EINVAL;
> +
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	old_inode = old_dentry->d_inode;
> +	new_inode = new_dentry->d_inode;
> +
> +	err = __exfat_rename(old_dir, EXFAT_I(old_inode), new_dir,
> new_dentry);
> +	if (err)
> +		goto unlock;
> +
> +	inode_inc_iversion(new_dir);
> +	new_dir->i_ctime = new_dir->i_mtime = new_dir->i_atime =
> +		current_time(new_dir);
> +	if (IS_DIRSYNC(new_dir))
> +		exfat_sync_inode(new_dir);
> +	else
> +		mark_inode_dirty(new_dir);
> +
> +	i_pos = ((loff_t)EXFAT_I(old_inode)->dir.dir << 32) |
> +		(EXFAT_I(old_inode)->entry & 0xffffffff);
> +	exfat_unhash_inode(old_inode);
> +	exfat_hash_inode(old_inode, i_pos);
> +	if (IS_DIRSYNC(new_dir))
> +		exfat_sync_inode(old_inode);
> +	else
> +		mark_inode_dirty(old_inode);
> +
> +	if (S_ISDIR(old_inode->i_mode) && old_dir != new_dir) {
> +		drop_nlink(old_dir);
> +		if (!new_inode)
> +			inc_nlink(new_dir);
> +	}
> +
> +	inode_inc_iversion(old_dir);
> +	old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
> +	if (IS_DIRSYNC(old_dir))
> +		exfat_sync_inode(old_dir);
> +	else
> +		mark_inode_dirty(old_dir);
> +
> +	if (new_inode) {
> +		exfat_unhash_inode(new_inode);
> +
> +		/* skip drop_nlink if new_inode already has been
> dropped */
> +		if (new_inode->i_nlink) {
> +			drop_nlink(new_inode);
> +			if (S_ISDIR(new_inode->i_mode))
> +				drop_nlink(new_inode);
> +		} else {
> +			exfat_msg(sb, KERN_WARNING,
> +					"abnormal access to an inode
> dropped");
> +			WARN_ON(new_inode->i_nlink == 0);
> +		}
> +		new_inode->i_ctime = current_time(new_inode);
> +	}
> +
> +unlock:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	return err;
> +}
> +
> +const struct inode_operations exfat_dir_inode_operations = {
> +	.create		= exfat_create,
> +	.lookup		= exfat_lookup,
> +	.unlink		= exfat_unlink,
> +	.mkdir		= exfat_mkdir,
> +	.rmdir		= exfat_rmdir,
> +	.rename		= exfat_rename,
> +	.setattr	= exfat_setattr,
> +	.getattr	= exfat_getattr,
> +};

RE: [PATCH v6 03/13] exfat: add inode operations

[Namjae Jeon]

> > +	ep2->stream_valid_size = cpu_to_le64(on_disk_size);
> > +	ep2->stream_size = ep2->stream_valid_size;
> > +
> > +	ret = exfat_update_dir_chksum_with_entry_set(sb, es, sync);
> > +	kfree(es);
> 
> The exfat_get_dentry_set() allocates the es by kmalloc? Am I correct?
Yes.
> 
> 
> > +	return ret;
> > +}
> > +

[PATCH v6 04/13] exfat: add directory operations

[Namjae Jeon]

This adds the implementation of directory operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/dir.c | 1310 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1310 insertions(+)
 create mode 100644 fs/exfat/dir.c

diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
new file mode 100644
index 000000000000..78ffc0f844be
--- /dev/null
+++ b/fs/exfat/dir.c
@@ -0,0 +1,1310 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/slab.h>
+#include <linux/bio.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+/* read a directory entry from the opened directory */
+static int exfat_readdir(struct inode *inode, struct exfat_dir_entry *dir_entry)
+{
+	int i, dentries_per_clu, dentries_per_clu_bits = 0;
+	unsigned int type, clu_offset;
+	sector_t sector;
+	struct exfat_chain dir, clu;
+	struct exfat_uni_name uni_name;
+	struct exfat_timestamp tm;
+	struct exfat_dentry *ep;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	unsigned int dentry = ei->rwoffset & 0xFFFFFFFF;
+	struct buffer_head *bh;
+
+	/* check if the given file ID is opened */
+	if (ei->type != TYPE_DIR)
+		return -EPERM;
+
+	if (ei->entry == -1)
+		exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	else
+		exfat_chain_set(&dir, ei->start_clu,
+			EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
+
+	dentries_per_clu = sbi->dentries_per_clu;
+	dentries_per_clu_bits = ilog2(dentries_per_clu);
+
+	clu_offset = dentry >> dentries_per_clu_bits;
+	exfat_chain_dup(&clu, &dir);
+
+	if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+		clu.dir += clu_offset;
+		clu.size -= clu_offset;
+	} else {
+		/* hint_information */
+		if (clu_offset > 0 && ei->hint_bmap.off != EOF_CLUSTER &&
+		    ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
+			clu_offset -= ei->hint_bmap.off;
+			clu.dir = ei->hint_bmap.clu;
+		}
+
+		while (clu_offset > 0) {
+			if (exfat_get_next_cluster(sb, &(clu.dir)))
+				return -EIO;
+
+			clu_offset--;
+		}
+	}
+
+	while (clu.dir != EOF_CLUSTER) {
+		i = dentry & (dentries_per_clu - 1);
+
+		for ( ; i < dentries_per_clu; i++, dentry++) {
+			ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
+			if (!ep)
+				return -EIO;
+
+			type = exfat_get_entry_type(ep);
+			if (type == TYPE_UNUSED) {
+				brelse(bh);
+				break;
+			}
+
+			if (type != TYPE_FILE && type != TYPE_DIR) {
+				brelse(bh);
+				continue;
+			}
+
+			dir_entry->attr = le16_to_cpu(ep->file_attr);
+
+			exfat_get_entry_time(ep, &tm, TM_CREATE);
+			dir_entry->create_timestamp.year = tm.year;
+			dir_entry->create_timestamp.month = tm.mon;
+			dir_entry->create_timestamp.day = tm.day;
+			dir_entry->create_timestamp.hour = tm.hour;
+			dir_entry->create_timestamp.minute = tm.min;
+			dir_entry->create_timestamp.second = tm.sec;
+			dir_entry->create_timestamp.milli_second = 0;
+
+			exfat_get_entry_time(ep, &tm, TM_MODIFY);
+			dir_entry->modify_timestamp.year = tm.year;
+			dir_entry->modify_timestamp.month = tm.mon;
+			dir_entry->modify_timestamp.day = tm.day;
+			dir_entry->modify_timestamp.hour = tm.hour;
+			dir_entry->modify_timestamp.minute = tm.min;
+			dir_entry->modify_timestamp.second = tm.sec;
+			dir_entry->modify_timestamp.milli_second = 0;
+
+			memset(&dir_entry->access_timestamp, 0,
+				sizeof(struct exfat_date_time));
+
+			*uni_name.name = 0x0;
+			exfat_get_uniname_from_ext_entry(sb, &dir, dentry,
+				uni_name.name);
+			exfat_nls_uni16s_to_vfsname(sb, &uni_name,
+				dir_entry->namebuf.lfn,
+				dir_entry->namebuf.lfnbuf_len);
+			brelse(bh);
+
+			ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
+			if (!ep)
+				return -EIO;
+			dir_entry->size = le64_to_cpu(ep->stream_valid_size);
+			brelse(bh);
+
+			ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
+			ei->hint_bmap.clu = clu.dir;
+
+			ei->rwoffset = ++dentry;
+			return 0;
+		}
+
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			if (--clu.size > 0)
+				clu.dir++;
+			else
+				clu.dir = EOF_CLUSTER;
+		} else {
+			if (exfat_get_next_cluster(sb, &(clu.dir)))
+				return -EIO;
+		}
+	}
+
+	dir_entry->namebuf.lfn[0] = '\0';
+	ei->rwoffset = dentry;
+	return 0;
+}
+
+static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
+{
+	nb->lfn = NULL;
+	nb->lfnbuf_len = 0;
+}
+
+static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
+{
+	nb->lfn = __getname();
+	if (!nb->lfn)
+		return -ENOMEM;
+	nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
+	return 0;
+}
+
+static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
+{
+	if (!nb->lfn)
+		return;
+
+	__putname(nb->lfn);
+	exfat_init_namebuf(nb);
+}
+
+/* skip iterating emit_dots when dir is empty */
+#define ITER_POS_FILLED_DOTS    (2)
+static int exfat_iterate(struct file *filp, struct dir_context *ctx)
+{
+	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct super_block *sb = inode->i_sb;
+	struct inode *tmp;
+	struct exfat_dir_entry de;
+	struct exfat_dentry_namebuf *nb = &(de.namebuf);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	unsigned long inum;
+	loff_t cpos, i_pos;
+	int err = 0, fake_offset = 0;
+
+	exfat_init_namebuf(nb);
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+
+	cpos = ctx->pos;
+	if (!dir_emit_dots(filp, ctx))
+		goto unlock;
+
+	if (ctx->pos == ITER_POS_FILLED_DOTS) {
+		cpos = 0;
+		fake_offset = 1;
+	}
+
+	if (cpos & (DENTRY_SIZE - 1)) {
+		err = -ENOENT;
+		goto unlock;
+	}
+
+	/* name buffer should be allocated before use */
+	err = exfat_alloc_namebuf(nb);
+	if (err)
+		goto unlock;
+get_new:
+	ei->rwoffset = EXFAT_B_TO_DEN(cpos);
+
+	if (cpos >= i_size_read(inode))
+		goto end_of_dir;
+
+	err = exfat_readdir(inode, &de);
+	if (err) {
+		/*
+		 * At least we tried to read a sector.  Move cpos to next sector
+		 * position (should be aligned).
+		 */
+		if (err == -EIO) {
+			cpos += 1 << (sb->s_blocksize_bits);
+			cpos &= ~(sb->s_blocksize - 1);
+		}
+
+		err = -EIO;
+		goto end_of_dir;
+	}
+
+	cpos = EXFAT_DEN_TO_B(ei->rwoffset);
+
+	if (!nb->lfn[0])
+		goto end_of_dir;
+
+	i_pos = ((loff_t)ei->start_clu << 32) |
+		((ei->rwoffset - 1) & 0xffffffff);
+	tmp = exfat_iget(sb, i_pos);
+	if (tmp) {
+		inum = tmp->i_ino;
+		iput(tmp);
+	} else {
+		inum = iunique(sb, EXFAT_ROOT_INO);
+	}
+
+	/*
+	 * Before calling dir_emit(), sb_lock should be released.
+	 * Because page fault can occur in dir_emit() when the size
+	 * of buffer given from user is larger than one page size.
+	 */
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+	if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
+			(de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
+		goto out_unlocked;
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+	ctx->pos = cpos;
+	goto get_new;
+
+end_of_dir:
+	if (!cpos && fake_offset)
+		cpos = ITER_POS_FILLED_DOTS;
+	ctx->pos = cpos;
+unlock:
+	mutex_unlock(&EXFAT_SB(sb)->s_lock);
+out_unlocked:
+	/*
+	 * To improve performance, free namebuf after unlock sb_lock.
+	 * If namebuf is not allocated, this function do nothing
+	 */
+	exfat_free_namebuf(nb);
+	return err;
+}
+
+const struct file_operations exfat_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate	= exfat_iterate,
+	.fsync		= generic_file_fsync,
+};
+
+int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
+{
+	int ret;
+
+	exfat_chain_set(clu, EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
+
+	ret = exfat_alloc_cluster(inode, 1, clu);
+	if (ret)
+		return ret;
+
+	return exfat_zeroed_cluster(inode, clu->dir);
+}
+
+static int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
+{
+	int len;
+
+	len = p_uniname->name_len;
+	if (len == 0)
+		return 0;
+
+	/* 1 file entry + 1 stream entry + name entries */
+	return ((len - 1) / 15 + 3);
+}
+
+/*
+ * input  : dir, uni_name
+ * output : num_of_entry
+ */
+int exfat_get_num_entries(struct exfat_uni_name *p_uniname)
+{
+	int num_entries;
+
+	num_entries = exfat_calc_num_entries(p_uniname);
+	if (num_entries == 0)
+		return -EINVAL;
+
+	return num_entries;
+}
+
+unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
+{
+	if (ep->type == EXFAT_UNUSED)
+		return TYPE_UNUSED;
+	if (IS_EXFAT_DELETED(ep->type))
+		return TYPE_DELETED;
+	if (ep->type == EXFAT_INVAL)
+		return TYPE_INVALID;
+	if (ep->type < 0xA0) {
+		if (ep->type == EXFAT_BITMAP)
+			return TYPE_BITMAP;
+		if (ep->type == EXFAT_UPCASE)
+			return TYPE_UPCASE;
+		if (ep->type == EXFAT_VOLUME)
+			return TYPE_VOLUME;
+		if (ep->type == EXFAT_FILE) {
+			if (le16_to_cpu(ep->file_attr) & ATTR_SUBDIR)
+				return TYPE_DIR;
+			return TYPE_FILE;
+		}
+		return TYPE_CRITICAL_PRI;
+	}
+	if (ep->type < 0xC0) {
+		if (ep->type == EXFAT_GUID)
+			return TYPE_GUID;
+		if (ep->type == EXFAT_PADDING)
+			return TYPE_PADDING;
+		if (ep->type == EXFAT_ACLTAB)
+			return TYPE_ACLTAB;
+		return TYPE_BENIGN_PRI;
+	}
+	if (ep->type < 0xE0) {
+		if (ep->type == EXFAT_STREAM)
+			return TYPE_STREAM;
+		if (ep->type == EXFAT_NAME)
+			return TYPE_EXTEND;
+		if (ep->type == EXFAT_ACL)
+			return TYPE_ACL;
+		return TYPE_CRITICAL_SEC;
+	}
+	return TYPE_BENIGN_SEC;
+}
+
+static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
+{
+	if (type == TYPE_UNUSED) {
+		ep->type = EXFAT_UNUSED;
+	} else if (type == TYPE_DELETED) {
+		ep->type &= EXFAT_DELETE;
+	} else if (type == TYPE_STREAM) {
+		ep->type = EXFAT_STREAM;
+	} else if (type == TYPE_EXTEND) {
+		ep->type = EXFAT_NAME;
+	} else if (type == TYPE_BITMAP) {
+		ep->type = EXFAT_BITMAP;
+	} else if (type == TYPE_UPCASE) {
+		ep->type = EXFAT_UPCASE;
+	} else if (type == TYPE_VOLUME) {
+		ep->type = EXFAT_VOLUME;
+	} else if (type == TYPE_DIR) {
+		ep->type = EXFAT_FILE;
+		ep->file_attr = ATTR_SUBDIR_LE;
+	} else if (type == TYPE_FILE) {
+		ep->type = EXFAT_FILE;
+		ep->file_attr = ATTR_ARCHIVE_LE;
+	}
+}
+
+void exfat_get_entry_time(struct exfat_dentry *ep, struct exfat_timestamp *tp,
+		unsigned char mode)
+{
+	unsigned short t = 0x00, d = 0x21;
+
+	switch (mode) {
+	case TM_CREATE:
+		t = le16_to_cpu(ep->file_create_time);
+		d = le16_to_cpu(ep->file_create_date);
+		break;
+	case TM_MODIFY:
+		t = le16_to_cpu(ep->file_modify_time);
+		d = le16_to_cpu(ep->file_modify_date);
+		break;
+	case TM_ACCESS:
+		t = le16_to_cpu(ep->file_access_time);
+		d = le16_to_cpu(ep->file_access_date);
+		break;
+	}
+
+	tp->sec  = (t & 0x001F) << 1;
+	tp->min  = (t >> 5) & 0x003F;
+	tp->hour = (t >> 11);
+	tp->day  = (d & 0x001F);
+	tp->mon  = (d >> 5) & 0x000F;
+	tp->year = (d >> 9);
+}
+
+void exfat_set_entry_time(struct exfat_dentry *ep,
+		struct exfat_timestamp *tp, unsigned char mode)
+{
+	unsigned short t, d;
+
+	t = (tp->hour << 11) | (tp->min << 5) | (tp->sec >> 1);
+	d = (tp->year <<  9) | (tp->mon << 5) |  tp->day;
+
+	switch (mode) {
+	case TM_CREATE:
+		ep->file_create_time = cpu_to_le16(t);
+		ep->file_create_date = cpu_to_le16(d);
+		break;
+	case TM_MODIFY:
+		ep->file_modify_time = cpu_to_le16(t);
+		ep->file_modify_date = cpu_to_le16(d);
+		break;
+	case TM_ACCESS:
+		ep->file_access_time = cpu_to_le16(t);
+		ep->file_access_date = cpu_to_le16(d);
+		break;
+	}
+}
+
+static void exfat_init_file_entry(struct super_block *sb,
+		struct exfat_dentry *ep, unsigned int type)
+{
+	struct exfat_timestamp tm, *tp;
+
+	exfat_set_entry_type(ep, type);
+
+	tp = exfat_tm_now(EXFAT_SB(sb), &tm);
+	exfat_set_entry_time(ep, tp, TM_CREATE);
+	exfat_set_entry_time(ep, tp, TM_MODIFY);
+	exfat_set_entry_time(ep, tp, TM_ACCESS);
+	ep->file_create_time_ms = 0;
+	ep->file_modify_time_ms = 0;
+	ep->file_access_time_ms = 0;
+}
+
+static void exfat_init_stream_entry(struct exfat_dentry *ep,
+		unsigned char flags, unsigned int start_clu,
+		unsigned long long size)
+{
+	exfat_set_entry_type(ep, TYPE_STREAM);
+	ep->stream_flags = flags;
+	ep->stream_start_clu = cpu_to_le32(start_clu);
+	ep->stream_valid_size = cpu_to_le64(size);
+	ep->stream_size = cpu_to_le64(size);
+}
+
+static void exfat_init_name_entry(struct exfat_dentry *ep,
+		unsigned short *uniname)
+{
+	int i;
+
+	exfat_set_entry_type(ep, TYPE_EXTEND);
+	ep->name_flags = 0x0;
+
+	for (i = 0; i < 15; i++) {
+		ep->name_unicode[i] = cpu_to_le16(*uniname);
+		if (*uniname == 0x0)
+			break;
+		uniname++;
+	}
+}
+
+int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
+		int entry, unsigned int type, unsigned int start_clu,
+		unsigned long long size)
+{
+	struct super_block *sb = inode->i_sb;
+	sector_t sector;
+	unsigned char flags;
+	struct exfat_dentry *ep;
+	struct buffer_head *bh;
+	int sync = IS_DIRSYNC(inode);
+
+	flags = (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN;
+
+	/*
+	 * We cannot use exfat_get_dentry_set here because file ep is not
+	 * initialized yet.
+	 */
+	ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
+	if (!ep)
+		return -EIO;
+
+	exfat_init_file_entry(sb, ep, type);
+	exfat_update_bh(sb, bh, sync);
+	brelse(bh);
+
+	ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
+	if (!ep)
+		return -EIO;
+
+	exfat_init_stream_entry(ep, flags, start_clu, size);
+	exfat_update_bh(sb, bh, sync);
+	brelse(bh);
+
+	return 0;
+}
+
+int update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
+		int entry)
+{
+	struct super_block *sb = inode->i_sb;
+	int ret = 0;
+	int i, num_entries;
+	sector_t sector;
+	unsigned short chksum;
+	struct exfat_dentry *ep, *fep;
+	struct buffer_head *fbh, *bh;
+
+	fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
+	if (!fep)
+		return -EIO;
+
+	num_entries = fep->file_num_ext + 1;
+	chksum = exfat_calc_chksum_2byte(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
+
+	for (i = 1; i < num_entries; i++) {
+		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
+		if (!ep) {
+			ret = -EIO;
+			goto release_fbh;
+		}
+		chksum = exfat_calc_chksum_2byte(ep, DENTRY_SIZE, chksum,
+				CS_DEFAULT);
+		brelse(bh);
+	}
+
+	fep->file_checksum = cpu_to_le16(chksum);
+	exfat_update_bh(sb, fbh, IS_DIRSYNC(inode));
+release_fbh:
+	brelse(fbh);
+	return ret;
+}
+
+int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
+		int entry, int num_entries, struct exfat_uni_name *p_uniname)
+{
+	struct super_block *sb = inode->i_sb;
+	int i;
+	sector_t sector;
+	unsigned short *uniname = p_uniname->name;
+	struct exfat_dentry *ep;
+	struct buffer_head *bh;
+	int sync = IS_DIRSYNC(inode);
+
+	ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
+	if (!ep)
+		return -EIO;
+
+	ep->file_num_ext = (unsigned char)(num_entries - 1);
+	exfat_update_bh(sb, bh, sync);
+	brelse(bh);
+
+	ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
+	if (!ep)
+		return -EIO;
+
+	ep->stream_name_len = p_uniname->name_len;
+	ep->stream_name_hash = cpu_to_le16(p_uniname->name_hash);
+	exfat_update_bh(sb, bh, sync);
+	brelse(bh);
+
+	for (i = 2; i < num_entries; i++) {
+		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
+		if (!ep)
+			return -EIO;
+
+		exfat_init_name_entry(ep, uniname);
+		exfat_update_bh(sb, bh, sync);
+		brelse(bh);
+		uniname += 15;
+	}
+
+	update_dir_chksum(inode, p_dir, entry);
+	return 0;
+}
+
+int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
+		int entry, int order, int num_entries)
+{
+	struct super_block *sb = inode->i_sb;
+	int i;
+	sector_t sector;
+	struct exfat_dentry *ep;
+	struct buffer_head *bh;
+
+	for (i = order; i < num_entries; i++) {
+		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
+		if (!ep)
+			return -EIO;
+
+		exfat_set_entry_type(ep, TYPE_DELETED);
+		exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
+		brelse(bh);
+	}
+
+	return 0;
+}
+
+int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
+		struct exfat_entry_set_cache *es, int sync)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+	sector_t sec = es->sector;
+	unsigned int off = es->offset;
+	int chksum_type = CS_DIR_ENTRY, i, num_entries = es->num_entries;
+	unsigned int buf_off = (off - es->offset);
+	unsigned int remaining_byte_in_sector, copy_entries, clu;
+	unsigned short chksum = 0;
+
+	for (i = 0; i < num_entries; i++) {
+		chksum = exfat_calc_chksum_2byte(&es->entries[i], DENTRY_SIZE,
+			chksum, chksum_type);
+		chksum_type = CS_DEFAULT;
+	}
+
+	es->entries[0].file_checksum = cpu_to_le16(chksum);
+
+	while (num_entries) {
+		/* write per sector base */
+		remaining_byte_in_sector = (1 << sb->s_blocksize_bits) - off;
+		copy_entries = min_t(int,
+			EXFAT_B_TO_DEN(remaining_byte_in_sector),
+			num_entries);
+		bh = sb_bread(sb, sec);
+		if (!bh)
+			goto err_out;
+		memcpy(bh->b_data + off,
+			(unsigned char *)&es->entries[0] + buf_off,
+			EXFAT_DEN_TO_B(copy_entries));
+		exfat_update_bh(sb, bh, sync);
+		brelse(bh);
+		num_entries -= copy_entries;
+
+		if (num_entries) {
+			/* get next sector */
+			if (exfat_is_last_sector_in_cluster(sbi, sec)) {
+				clu = exfat_sector_to_cluster(sbi, sec);
+				if (es->alloc_flag == ALLOC_NO_FAT_CHAIN)
+					clu++;
+				else if (exfat_get_next_cluster(sb, &clu))
+					goto err_out;
+				sec = exfat_cluster_to_sector(sbi, clu);
+			} else {
+				sec++;
+			}
+			off = 0;
+			buf_off += EXFAT_DEN_TO_B(copy_entries);
+		}
+	}
+
+	return 0;
+err_out:
+	return -EIO;
+}
+
+static int exfat_walk_fat_chain(struct super_block *sb,
+		struct exfat_chain *p_dir, unsigned int byte_offset,
+		unsigned int *clu)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int clu_offset;
+	unsigned int cur_clu;
+
+	clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
+	cur_clu = p_dir->dir;
+
+	if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
+		cur_clu += clu_offset;
+	} else {
+		while (clu_offset > 0) {
+			if (exfat_get_next_cluster(sb, &cur_clu))
+				return -EIO;
+			if (cur_clu == EOF_CLUSTER) {
+				exfat_fs_error(sb,
+					"invalid dentry access beyond EOF (clu : %u, eidx : %d)",
+					p_dir->dir,
+					EXFAT_B_TO_DEN(byte_offset));
+				return -EIO;
+			}
+			clu_offset--;
+		}
+	}
+
+	*clu = cur_clu;
+	return 0;
+}
+
+int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
+		int entry, sector_t *sector, int *offset)
+{
+	int ret;
+	unsigned int off, clu = 0;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	off = EXFAT_DEN_TO_B(entry);
+
+	ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
+	if (ret)
+		return ret;
+
+	/* byte offset in cluster */
+	off = EXFAT_CLU_OFFSET(off, sbi);
+
+	/* byte offset in sector    */
+	*offset = EXFAT_BLK_OFFSET(off, sb);
+
+	/* sector offset in cluster */
+	*sector = EXFAT_B_TO_BLK(off, sb);
+	*sector += exfat_cluster_to_sector(sbi, clu);
+	return 0;
+}
+
+#define EXFAT_MAX_RA_SIZE     (128*1024)
+static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+	unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
+	unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
+	unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
+	unsigned int ra_count = min(adj_ra_count, max_ra_count);
+
+	/* Read-ahead is not required */
+	if (sbi->sect_per_clus == 1)
+		return 0;
+
+	if (sec < sbi->data_start_sector) {
+		exfat_msg(sb, KERN_ERR,
+			"requested sector is invalid(sect:%llu, root:%llu)",
+			sec, sbi->data_start_sector);
+		return -EIO;
+	}
+
+	/* Not sector aligned with ra_count, resize ra_count to page size */
+	if ((sec - sbi->data_start_sector) & (ra_count - 1))
+		ra_count = page_ra_count;
+
+	bh = sb_find_get_block(sb, sec);
+	if (!bh || !buffer_uptodate(bh)) {
+		unsigned int i;
+
+		for (i = 0; i < ra_count; i++)
+			sb_breadahead(sb, (sector_t)(sec + i));
+	}
+	brelse(bh);
+	return 0;
+}
+
+struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
+		struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
+		sector_t *sector)
+{
+	unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
+	int off;
+	sector_t sec;
+
+	if (p_dir->dir == DIR_DELETED) {
+		exfat_msg(sb, KERN_ERR, "abnormal access to deleted dentry\n");
+		return NULL;
+	}
+
+	if (exfat_find_location(sb, p_dir, entry, &sec, &off))
+		return NULL;
+
+	if (p_dir->dir != FREE_CLUSTER &&
+			!(entry & (dentries_per_page - 1)))
+		exfat_dir_readahead(sb, sec);
+
+	*bh = sb_bread(sb, sec);
+	if (!*bh)
+		return NULL;
+
+	if (sector)
+		*sector = sec;
+	return (struct exfat_dentry *)((*bh)->b_data + off);
+}
+
+enum exfat_validate_dentry_mode {
+	ES_MODE_STARTED,
+	ES_MODE_GET_FILE_ENTRY,
+	ES_MODE_GET_STRM_ENTRY,
+	ES_MODE_GET_NAME_ENTRY,
+	ES_MODE_GET_CRITICAL_SEC_ENTRY,
+};
+
+static bool exfat_validate_entry(unsigned int type,
+		enum exfat_validate_dentry_mode *mode)
+{
+	if (type == TYPE_UNUSED || type == TYPE_DELETED)
+		return false;
+
+	switch (*mode) {
+	case ES_MODE_STARTED:
+		if  (type != TYPE_FILE && type != TYPE_DIR)
+			return false;
+		*mode = ES_MODE_GET_FILE_ENTRY;
+		return true;
+	case ES_MODE_GET_FILE_ENTRY:
+		if (type != TYPE_STREAM)
+			return false;
+		*mode = ES_MODE_GET_STRM_ENTRY;
+		return true;
+	case ES_MODE_GET_STRM_ENTRY:
+		if (type != TYPE_EXTEND)
+			return false;
+		*mode = ES_MODE_GET_NAME_ENTRY;
+		return true;
+	case ES_MODE_GET_NAME_ENTRY:
+		if (type == TYPE_STREAM)
+			return false;
+		if (type != TYPE_EXTEND) {
+			if (!(type & TYPE_CRITICAL_SEC))
+				return false;
+			*mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
+		}
+		return true;
+	case ES_MODE_GET_CRITICAL_SEC_ENTRY:
+		if (type == TYPE_EXTEND || type == TYPE_STREAM)
+			return false;
+		if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
+			return false;
+		return true;
+	default:
+		WARN_ON_ONCE(1);
+		return false;
+	}
+}
+
+/*
+ * Returns a set of dentries for a file or dir.
+ *
+ * Note that this is a copy (dump) of dentries so that user should
+ * call write_entry_set() to apply changes made in this entry set
+ * to the real device.
+ *
+ * in:
+ *   sb+p_dir+entry: indicates a file/dir
+ *   type:  specifies how many dentries should be included.
+ * out:
+ *   file_ep: will point the first dentry(= file dentry) on success
+ * return:
+ *   pointer of entry set on success,
+ *   NULL on failure.
+ */
+struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
+		struct exfat_chain *p_dir, int entry, unsigned int type,
+		struct exfat_dentry **file_ep)
+{
+	int ret;
+	unsigned int off, byte_offset, clu = 0;
+	unsigned int entry_type;
+	sector_t sec;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_entry_set_cache *es;
+	struct exfat_dentry *ep, *pos;
+	unsigned char num_entries;
+	enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
+	struct buffer_head *bh;
+
+	if (p_dir->dir == DIR_DELETED) {
+		exfat_msg(sb, KERN_ERR, "access to deleted dentry\n");
+		return NULL;
+	}
+
+	byte_offset = EXFAT_DEN_TO_B(entry);
+	ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
+	if (ret)
+		return NULL;
+
+	/* byte offset in cluster */
+	byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
+
+	/* byte offset in sector */
+	off = EXFAT_BLK_OFFSET(byte_offset, sb);
+
+	/* sector offset in cluster */
+	sec = EXFAT_B_TO_BLK(byte_offset, sb);
+	sec += exfat_cluster_to_sector(sbi, clu);
+
+	bh = sb_bread(sb, sec);
+	if (!bh)
+		return NULL;
+
+	ep = (struct exfat_dentry *)(bh->b_data + off);
+	entry_type = exfat_get_entry_type(ep);
+
+	if (entry_type != TYPE_FILE && entry_type != TYPE_DIR)
+		goto release_bh;
+
+	num_entries = type == ES_ALL_ENTRIES ? ep->file_num_ext + 1 : type;
+	es = kmalloc(struct_size(es, entries, num_entries), GFP_KERNEL);
+	if (!es)
+		goto release_bh;
+
+	es->num_entries = num_entries;
+	es->sector = sec;
+	es->offset = off;
+	es->alloc_flag = p_dir->flags;
+
+	pos = &es->entries[0];
+
+	while (num_entries) {
+		if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+			goto free_es;
+
+		/* copy dentry */
+		memcpy(pos, ep, sizeof(struct exfat_dentry));
+
+		if (--num_entries == 0)
+			break;
+
+		if (((off + DENTRY_SIZE) & (sb->s_blocksize - 1)) <
+		    (off & (sb->s_blocksize - 1))) {
+			/* get the next sector */
+			if (exfat_is_last_sector_in_cluster(sbi, sec)) {
+				if (es->alloc_flag == ALLOC_NO_FAT_CHAIN)
+					clu++;
+				else if (exfat_get_next_cluster(sb, &clu))
+					goto free_es;
+				sec = exfat_cluster_to_sector(sbi, clu);
+			} else {
+				sec++;
+			}
+
+			brelse(bh);
+			bh = sb_bread(sb, sec);
+			if (!bh)
+				goto free_es;
+			off = 0;
+			ep = (struct exfat_dentry *)bh->b_data;
+		} else {
+			ep++;
+			off += DENTRY_SIZE;
+		}
+		pos++;
+	}
+
+	if (file_ep)
+		*file_ep = &es->entries[0];
+	brelse(bh);
+	return es;
+
+free_es:
+	kfree(es);
+release_bh:
+	brelse(bh);
+	return NULL;
+}
+
+static int exfat_extract_uni_name(struct exfat_dentry *ep,
+		unsigned short *uniname)
+{
+	int i, len = 0;
+
+	for (i = 0; i < 15; i++) {
+		*uniname = le16_to_cpu(ep->name_unicode[i]);
+		if (*uniname == 0x0)
+			return len;
+		uniname++;
+		len++;
+	}
+
+	*uniname = 0x0;
+	return len;
+
+}
+
+enum {
+	DIRENT_STEP_FILE,
+	DIRENT_STEP_STRM,
+	DIRENT_STEP_NAME,
+	DIRENT_STEP_SECD,
+};
+
+/*
+ * return values:
+ *   >= 0	: return dir entiry position with the name in dir
+ *   -EEXIST	: (root dir, ".") it is the root dir itself
+ *   -ENOENT	: entry with the name does not exist
+ *   -EIO	: I/O error
+ */
+int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
+		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
+		int num_entries, unsigned int type)
+{
+	int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
+	int order, step, name_len = 0;
+	int dentries_per_clu, num_empty = 0;
+	unsigned int entry_type;
+	unsigned short *uniname = NULL;
+	struct exfat_chain clu;
+	struct exfat_hint *hint_stat = &ei->hint_stat;
+	struct exfat_hint_femp candi_empty;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	dentries_per_clu = sbi->dentries_per_clu;
+
+	exfat_chain_dup(&clu, p_dir);
+
+	if (hint_stat->eidx) {
+		clu.dir = hint_stat->clu;
+		dentry = hint_stat->eidx;
+		end_eidx = dentry;
+	}
+
+	candi_empty.eidx = EXFAT_HINT_NONE;
+rewind:
+	order = 0;
+	step = DIRENT_STEP_FILE;
+	while (clu.dir != EOF_CLUSTER) {
+		i = dentry & (dentries_per_clu - 1);
+		for (; i < dentries_per_clu; i++, dentry++) {
+			struct exfat_dentry *ep;
+			struct buffer_head *bh;
+
+			if (rewind && dentry == end_eidx)
+				goto not_found;
+
+			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
+			if (!ep)
+				return -EIO;
+
+			entry_type = exfat_get_entry_type(ep);
+
+			if (entry_type == TYPE_UNUSED ||
+			    entry_type == TYPE_DELETED) {
+				step = DIRENT_STEP_FILE;
+
+				num_empty++;
+				if (candi_empty.eidx == EXFAT_HINT_NONE &&
+						num_empty == 1) {
+					exfat_chain_set(&candi_empty.cur,
+						clu.dir, clu.size, clu.flags);
+				}
+
+				if (candi_empty.eidx == EXFAT_HINT_NONE &&
+						num_empty >= num_entries) {
+					candi_empty.eidx =
+						dentry - (num_empty - 1);
+					WARN_ON(candi_empty.eidx < 0);
+					candi_empty.count = num_empty;
+
+					if (ei->hint_femp.eidx ==
+							EXFAT_HINT_NONE ||
+						candi_empty.eidx <=
+							 ei->hint_femp.eidx) {
+						memcpy(&ei->hint_femp,
+							&candi_empty,
+							sizeof(candi_empty));
+					}
+				}
+
+				brelse(bh);
+				if (entry_type == TYPE_UNUSED)
+					goto not_found;
+				continue;
+			}
+
+			num_empty = 0;
+			candi_empty.eidx = EXFAT_HINT_NONE;
+
+			if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
+				step = DIRENT_STEP_FILE;
+				if (type == TYPE_ALL || type == entry_type) {
+					num_ext = ep->file_num_ext;
+					step = DIRENT_STEP_STRM;
+				}
+				brelse(bh);
+				continue;
+			}
+
+			if (entry_type == TYPE_STREAM) {
+				unsigned short name_hash;
+
+				if (step != DIRENT_STEP_STRM) {
+					step = DIRENT_STEP_FILE;
+					brelse(bh);
+					continue;
+				}
+				step = DIRENT_STEP_FILE;
+				name_hash = le16_to_cpu(ep->stream_name_hash);
+				if (p_uniname->name_hash == name_hash &&
+				    p_uniname->name_len ==
+						ep->stream_name_len) {
+					step = DIRENT_STEP_NAME;
+					order = 1;
+					name_len = 0;
+				}
+				brelse(bh);
+				continue;
+			}
+
+			brelse(bh);
+			if (entry_type == TYPE_EXTEND) {
+				unsigned short entry_uniname[16], unichar;
+
+				if (step != DIRENT_STEP_NAME) {
+					step = DIRENT_STEP_FILE;
+					continue;
+				}
+
+				if (++order == 2)
+					uniname = p_uniname->name;
+				else
+					uniname += 15;
+
+				len = exfat_extract_uni_name(
+						ep, entry_uniname);
+				name_len += len;
+
+				unichar = *(uniname+len);
+				*(uniname+len) = 0x0;
+
+				if (exfat_nls_cmp_uniname(sb, uniname,
+							entry_uniname)) {
+					step = DIRENT_STEP_FILE;
+				} else if (name_len == p_uniname->name_len) {
+					if (order == num_ext)
+						goto found;
+					step = DIRENT_STEP_SECD;
+				}
+
+				*(uniname+len) = unichar;
+				continue;
+			}
+
+			if (entry_type &
+					(TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
+				if (step == DIRENT_STEP_SECD) {
+					if (++order == num_ext)
+						goto found;
+					continue;
+				}
+			}
+			step = DIRENT_STEP_FILE;
+		}
+
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			if (--clu.size > 0)
+				clu.dir++;
+			else
+				clu.dir = EOF_CLUSTER;
+		} else {
+			if (exfat_get_next_cluster(sb, &clu.dir))
+				return -EIO;
+		}
+	}
+
+not_found:
+	/*
+	 * We started at not 0 index,so we should try to find target
+	 * from 0 index to the index we started at.
+	 */
+	if (!rewind && end_eidx) {
+		rewind = 1;
+		dentry = 0;
+		clu.dir = p_dir->dir;
+		/* reset empty hint */
+		num_empty = 0;
+		candi_empty.eidx = EXFAT_HINT_NONE;
+		goto rewind;
+	}
+
+	/* initialized hint_stat */
+	hint_stat->clu = p_dir->dir;
+	hint_stat->eidx = 0;
+	return -ENOENT;
+
+found:
+	/* next dentry we'll find is out of this cluster */
+	if (!((dentry + 1) & (dentries_per_clu - 1))) {
+		int ret = 0;
+
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			if (--clu.size > 0)
+				clu.dir++;
+			else
+				clu.dir = EOF_CLUSTER;
+		} else {
+			ret = exfat_get_next_cluster(sb, &clu.dir);
+		}
+
+		if (ret || clu.dir != EOF_CLUSTER) {
+			/* just initialized hint_stat */
+			hint_stat->clu = p_dir->dir;
+			hint_stat->eidx = 0;
+			return (dentry - num_ext);
+		}
+	}
+
+	hint_stat->clu = clu.dir;
+	hint_stat->eidx = dentry + 1;
+	return dentry - num_ext;
+}
+
+int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
+		int entry, struct exfat_dentry *ep)
+{
+	int i, count = 0;
+	unsigned int type;
+	struct exfat_dentry *ext_ep;
+	struct buffer_head *bh;
+
+	for (i = 0, entry++; i < ep->file_num_ext; i++, entry++) {
+		ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
+		if (!ext_ep)
+			return -EIO;
+
+		type = exfat_get_entry_type(ext_ep);
+		brelse(bh);
+		if (type == TYPE_EXTEND || type == TYPE_STREAM)
+			count++;
+		else
+			break;
+	}
+	return count;
+}
+
+void exfat_get_uniname_from_ext_entry(struct super_block *sb,
+		struct exfat_chain *p_dir, int entry, unsigned short *uniname)
+{
+	int i;
+	struct exfat_dentry *ep;
+	struct exfat_entry_set_cache *es;
+
+	es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES, &ep);
+	if (!es)
+		return;
+
+	if (es->num_entries < 3)
+		goto free_es;
+
+	ep += 2;
+
+	/*
+	 * First entry  : file entry
+	 * Second entry : stream-extension entry
+	 * Third entry  : first file-name entry
+	 * So, the index of first file-name dentry should start from 2.
+	 */
+	for (i = 2; i < es->num_entries; i++, ep++) {
+		/* end of name entry */
+		if (exfat_get_entry_type(ep) != TYPE_EXTEND)
+			goto free_es;
+
+		exfat_extract_uni_name(ep, uniname);
+		uniname += 15;
+	}
+
+free_es:
+	kfree(es);
+}
+
+int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
+{
+	int i, count = 0;
+	int dentries_per_clu;
+	unsigned int entry_type;
+	struct exfat_chain clu;
+	struct exfat_dentry *ep;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+
+	dentries_per_clu = sbi->dentries_per_clu;
+
+	exfat_chain_dup(&clu, p_dir);
+
+	while (clu.dir != EOF_CLUSTER) {
+		for (i = 0; i < dentries_per_clu; i++) {
+			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
+			if (!ep)
+				return -EIO;
+			entry_type = exfat_get_entry_type(ep);
+			brelse(bh);
+
+			if (entry_type == TYPE_UNUSED)
+				return count;
+			if (entry_type != TYPE_DIR)
+				continue;
+			count++;
+		}
+
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			if (--clu.size > 0)
+				clu.dir++;
+			else
+				clu.dir = EOF_CLUSTER;
+		} else {
+			if (exfat_get_next_cluster(sb, &(clu.dir)))
+				return -EIO;
+		}
+	}
+
+	return count;
+}
-- 
2.17.1

Re: [PATCH v6 04/13] exfat: add directory operations

[Vyacheslav Dubeyko]

On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of directory operations for exfat.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
>  fs/exfat/dir.c | 1310
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 1310 insertions(+)
>  create mode 100644 fs/exfat/dir.c
> 
> diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
> new file mode 100644
> index 000000000000..78ffc0f844be
> --- /dev/null
> +++ b/fs/exfat/dir.c
> @@ -0,0 +1,1310 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/bio.h>
> +#include <linux/buffer_head.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +/* read a directory entry from the opened directory */
> +static int exfat_readdir(struct inode *inode, struct exfat_dir_entry
> *dir_entry)
> +{
> +	int i, dentries_per_clu, dentries_per_clu_bits = 0;
> +	unsigned int type, clu_offset;
> +	sector_t sector;
> +	struct exfat_chain dir, clu;
> +	struct exfat_uni_name uni_name;
> +	struct exfat_timestamp tm;
> +	struct exfat_dentry *ep;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	unsigned int dentry = ei->rwoffset & 0xFFFFFFFF;
> +	struct buffer_head *bh;
> +
> +	/* check if the given file ID is opened */
> +	if (ei->type != TYPE_DIR)
> +		return -EPERM;
> +
> +	if (ei->entry == -1)
> +		exfat_chain_set(&dir, sbi->root_dir, 0,
> ALLOC_FAT_CHAIN);
> +	else
> +		exfat_chain_set(&dir, ei->start_clu,
> +			EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei-
> >flags);
> +
> +	dentries_per_clu = sbi->dentries_per_clu;
> +	dentries_per_clu_bits = ilog2(dentries_per_clu);
> +
> +	clu_offset = dentry >> dentries_per_clu_bits;
> +	exfat_chain_dup(&clu, &dir);
> +
> +	if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +		clu.dir += clu_offset;
> +		clu.size -= clu_offset;
> +	} else {
> +		/* hint_information */
> +		if (clu_offset > 0 && ei->hint_bmap.off != EOF_CLUSTER
> &&
> +		    ei->hint_bmap.off > 0 && clu_offset >= ei-
> >hint_bmap.off) {
> +			clu_offset -= ei->hint_bmap.off;
> +			clu.dir = ei->hint_bmap.clu;
> +		}
> +
> +		while (clu_offset > 0) {
> +			if (exfat_get_next_cluster(sb, &(clu.dir)))
> +				return -EIO;
> +
> +			clu_offset--;
> +		}
> +	}
> +
> +	while (clu.dir != EOF_CLUSTER) {
> +		i = dentry & (dentries_per_clu - 1);
> +
> +		for ( ; i < dentries_per_clu; i++, dentry++) {
> +			ep = exfat_get_dentry(sb, &clu, i, &bh,
> &sector);
> +			if (!ep)
> +				return -EIO;
> +
> +			type = exfat_get_entry_type(ep);
> +			if (type == TYPE_UNUSED) {
> +				brelse(bh);
> +				break;
> +			}
> +
> +			if (type != TYPE_FILE && type != TYPE_DIR) {
> +				brelse(bh);
> +				continue;
> +			}
> +
> +			dir_entry->attr = le16_to_cpu(ep->file_attr);
> +
> +			exfat_get_entry_time(ep, &tm, TM_CREATE);
> +			dir_entry->create_timestamp.year = tm.year;
> +			dir_entry->create_timestamp.month = tm.mon;
> +			dir_entry->create_timestamp.day = tm.day;
> +			dir_entry->create_timestamp.hour = tm.hour;
> +			dir_entry->create_timestamp.minute = tm.min;
> +			dir_entry->create_timestamp.second = tm.sec;
> +			dir_entry->create_timestamp.milli_second = 0;
> +
> +			exfat_get_entry_time(ep, &tm, TM_MODIFY);
> +			dir_entry->modify_timestamp.year = tm.year;
> +			dir_entry->modify_timestamp.month = tm.mon;
> +			dir_entry->modify_timestamp.day = tm.day;
> +			dir_entry->modify_timestamp.hour = tm.hour;
> +			dir_entry->modify_timestamp.minute = tm.min;
> +			dir_entry->modify_timestamp.second = tm.sec;
> +			dir_entry->modify_timestamp.milli_second = 0;
> +
> +			memset(&dir_entry->access_timestamp, 0,
> +				sizeof(struct exfat_date_time));
> +
> +			*uni_name.name = 0x0;
> +			exfat_get_uniname_from_ext_entry(sb, &dir,
> dentry,
> +				uni_name.name);
> +			exfat_nls_uni16s_to_vfsname(sb, &uni_name,
> +				dir_entry->namebuf.lfn,
> +				dir_entry->namebuf.lfnbuf_len);
> +			brelse(bh);
> +
> +			ep = exfat_get_dentry(sb, &clu, i + 1, &bh,
> NULL);
> +			if (!ep)
> +				return -EIO;
> +			dir_entry->size = le64_to_cpu(ep-
> >stream_valid_size);
> +			brelse(bh);
> +
> +			ei->hint_bmap.off = dentry >>
> dentries_per_clu_bits;
> +			ei->hint_bmap.clu = clu.dir;
> +
> +			ei->rwoffset = ++dentry;
> +			return 0;
> +		}
> +
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			if (--clu.size > 0)
> +				clu.dir++;
> +			else
> +				clu.dir = EOF_CLUSTER;
> +		} else {
> +			if (exfat_get_next_cluster(sb, &(clu.dir)))
> +				return -EIO;
> +		}
> +	}
> +
> +	dir_entry->namebuf.lfn[0] = '\0';
> +	ei->rwoffset = dentry;
> +	return 0;
> +}
> +
> +static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
> +{
> +	nb->lfn = NULL;
> +	nb->lfnbuf_len = 0;
> +}
> +
> +static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
> +{
> +	nb->lfn = __getname();
> +	if (!nb->lfn)
> +		return -ENOMEM;
> +	nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
> +	return 0;
> +}
> +
> +static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
> +{
> +	if (!nb->lfn)
> +		return;
> +
> +	__putname(nb->lfn);
> +	exfat_init_namebuf(nb);
> +}
> +
> +/* skip iterating emit_dots when dir is empty */
> +#define ITER_POS_FILLED_DOTS    (2)
> +static int exfat_iterate(struct file *filp, struct dir_context *ctx)
> +{
> +	struct inode *inode = filp->f_path.dentry->d_inode;
> +	struct super_block *sb = inode->i_sb;
> +	struct inode *tmp;
> +	struct exfat_dir_entry de;
> +	struct exfat_dentry_namebuf *nb = &(de.namebuf);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	unsigned long inum;
> +	loff_t cpos, i_pos;
> +	int err = 0, fake_offset = 0;
> +
> +	exfat_init_namebuf(nb);
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +
> +	cpos = ctx->pos;
> +	if (!dir_emit_dots(filp, ctx))
> +		goto unlock;
> +
> +	if (ctx->pos == ITER_POS_FILLED_DOTS) {
> +		cpos = 0;
> +		fake_offset = 1;
> +	}
> +
> +	if (cpos & (DENTRY_SIZE - 1)) {
> +		err = -ENOENT;
> +		goto unlock;
> +	}
> +
> +	/* name buffer should be allocated before use */
> +	err = exfat_alloc_namebuf(nb);
> +	if (err)
> +		goto unlock;
> +get_new:
> +	ei->rwoffset = EXFAT_B_TO_DEN(cpos);
> +
> +	if (cpos >= i_size_read(inode))
> +		goto end_of_dir;
> +
> +	err = exfat_readdir(inode, &de);
> +	if (err) {
> +		/*
> +		 * At least we tried to read a sector.  Move cpos to
> next sector
> +		 * position (should be aligned).
> +		 */
> +		if (err == -EIO) {
> +			cpos += 1 << (sb->s_blocksize_bits);
> +			cpos &= ~(sb->s_blocksize - 1);
> +		}
> +
> +		err = -EIO;
> +		goto end_of_dir;
> +	}
> +
> +	cpos = EXFAT_DEN_TO_B(ei->rwoffset);
> +
> +	if (!nb->lfn[0])
> +		goto end_of_dir;
> +
> +	i_pos = ((loff_t)ei->start_clu << 32) |
> +		((ei->rwoffset - 1) & 0xffffffff);
> +	tmp = exfat_iget(sb, i_pos);
> +	if (tmp) {
> +		inum = tmp->i_ino;
> +		iput(tmp);
> +	} else {
> +		inum = iunique(sb, EXFAT_ROOT_INO);
> +	}
> +
> +	/*
> +	 * Before calling dir_emit(), sb_lock should be released.
> +	 * Because page fault can occur in dir_emit() when the size
> +	 * of buffer given from user is larger than one page size.
> +	 */
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
> +			(de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
> +		goto out_unlocked;
> +	mutex_lock(&EXFAT_SB(sb)->s_lock);
> +	ctx->pos = cpos;
> +	goto get_new;
> +
> +end_of_dir:
> +	if (!cpos && fake_offset)
> +		cpos = ITER_POS_FILLED_DOTS;
> +	ctx->pos = cpos;
> +unlock:
> +	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +out_unlocked:
> +	/*
> +	 * To improve performance, free namebuf after unlock sb_lock.
> +	 * If namebuf is not allocated, this function do nothing
> +	 */
> +	exfat_free_namebuf(nb);
> +	return err;
> +}
> +
> +const struct file_operations exfat_dir_operations = {
> +	.llseek		= generic_file_llseek,
> +	.read		= generic_read_dir,
> +	.iterate	= exfat_iterate,
> +	.fsync		= generic_file_fsync,
> +};
> +
> +int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain
> *clu)
> +{
> +	int ret;
> +
> +	exfat_chain_set(clu, EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
> +
> +	ret = exfat_alloc_cluster(inode, 1, clu);
> +	if (ret)
> +		return ret;
> +
> +	return exfat_zeroed_cluster(inode, clu->dir);
> +}
> +
> +static int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
> +{
> +	int len;
> +
> +	len = p_uniname->name_len;
> +	if (len == 0)
> +		return 0;
> +
> +	/* 1 file entry + 1 stream entry + name entries */
> +	return ((len - 1) / 15 + 3);


It's hard to follow why 15 + 3. Maybe, it makes sense to introduce some
constants and to add some comments here?

> +}
> +
> +/*
> + * input  : dir, uni_name
> + * output : num_of_entry
> + */
> +int exfat_get_num_entries(struct exfat_uni_name *p_uniname)
> +{
> +	int num_entries;
> +
> +	num_entries = exfat_calc_num_entries(p_uniname);
> +	if (num_entries == 0)
> +		return -EINVAL;

Maybe -ENODATA or -ENOENT will be better and more clear here?

> +
> +	return num_entries;
> +}
> +
> +unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
> +{
> +	if (ep->type == EXFAT_UNUSED)
> +		return TYPE_UNUSED;
> +	if (IS_EXFAT_DELETED(ep->type))
> +		return TYPE_DELETED;
> +	if (ep->type == EXFAT_INVAL)
> +		return TYPE_INVALID;
> +	if (ep->type < 0xA0) {

What 0xA0 means here?

> +		if (ep->type == EXFAT_BITMAP)
> +			return TYPE_BITMAP;
> +		if (ep->type == EXFAT_UPCASE)
> +			return TYPE_UPCASE;
> +		if (ep->type == EXFAT_VOLUME)
> +			return TYPE_VOLUME;
> +		if (ep->type == EXFAT_FILE) {
> +			if (le16_to_cpu(ep->file_attr) & ATTR_SUBDIR)
> +				return TYPE_DIR;
> +			return TYPE_FILE;
> +		}
> +		return TYPE_CRITICAL_PRI;
> +	}
> +	if (ep->type < 0xC0) {

Ditto about 0xC0.

> +		if (ep->type == EXFAT_GUID)
> +			return TYPE_GUID;
> +		if (ep->type == EXFAT_PADDING)
> +			return TYPE_PADDING;
> +		if (ep->type == EXFAT_ACLTAB)
> +			return TYPE_ACLTAB;
> +		return TYPE_BENIGN_PRI;
> +	}
> +	if (ep->type < 0xE0) {

Ditto about 0xE0.

> +		if (ep->type == EXFAT_STREAM)
> +			return TYPE_STREAM;
> +		if (ep->type == EXFAT_NAME)
> +			return TYPE_EXTEND;
> +		if (ep->type == EXFAT_ACL)
> +			return TYPE_ACL;
> +		return TYPE_CRITICAL_SEC;
> +	}
> +	return TYPE_BENIGN_SEC;
> +}
> +
> +static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned
> int type)
> +{
> +	if (type == TYPE_UNUSED) {
> +		ep->type = EXFAT_UNUSED;
> +	} else if (type == TYPE_DELETED) {
> +		ep->type &= EXFAT_DELETE;
> +	} else if (type == TYPE_STREAM) {
> +		ep->type = EXFAT_STREAM;
> +	} else if (type == TYPE_EXTEND) {
> +		ep->type = EXFAT_NAME;
> +	} else if (type == TYPE_BITMAP) {
> +		ep->type = EXFAT_BITMAP;
> +	} else if (type == TYPE_UPCASE) {
> +		ep->type = EXFAT_UPCASE;
> +	} else if (type == TYPE_VOLUME) {
> +		ep->type = EXFAT_VOLUME;
> +	} else if (type == TYPE_DIR) {
> +		ep->type = EXFAT_FILE;
> +		ep->file_attr = ATTR_SUBDIR_LE;
> +	} else if (type == TYPE_FILE) {
> +		ep->type = EXFAT_FILE;
> +		ep->file_attr = ATTR_ARCHIVE_LE;
> +	}
> +}
> +
> +void exfat_get_entry_time(struct exfat_dentry *ep, struct
> exfat_timestamp *tp,
> +		unsigned char mode)
> +{
> +	unsigned short t = 0x00, d = 0x21;
> +
> +	switch (mode) {
> +	case TM_CREATE:
> +		t = le16_to_cpu(ep->file_create_time);
> +		d = le16_to_cpu(ep->file_create_date);
> +		break;
> +	case TM_MODIFY:
> +		t = le16_to_cpu(ep->file_modify_time);
> +		d = le16_to_cpu(ep->file_modify_date);
> +		break;
> +	case TM_ACCESS:
> +		t = le16_to_cpu(ep->file_access_time);
> +		d = le16_to_cpu(ep->file_access_date);
> +		break;
> +	}
> +
> +	tp->sec  = (t & 0x001F) << 1;
> +	tp->min  = (t >> 5) & 0x003F;
> +	tp->hour = (t >> 11);
> +	tp->day  = (d & 0x001F);
> +	tp->mon  = (d >> 5) & 0x000F;
> +	tp->year = (d >> 9);

I believe that it will be much clear to introduce some constants
instead of teh hardcoded values. Otherwise, it's really hard to folow
the logic of the method. What do you think?


> +}
> +
> +void exfat_set_entry_time(struct exfat_dentry *ep,
> +		struct exfat_timestamp *tp, unsigned char mode)
> +{
> +	unsigned short t, d;
> +
> +	t = (tp->hour << 11) | (tp->min << 5) | (tp->sec >> 1);
> +	d = (tp->year <<  9) | (tp->mon << 5) |  tp->day;
> +

Ditto about the hardcoded values.

> +	switch (mode) {
> +	case TM_CREATE:
> +		ep->file_create_time = cpu_to_le16(t);
> +		ep->file_create_date = cpu_to_le16(d);
> +		break;
> +	case TM_MODIFY:
> +		ep->file_modify_time = cpu_to_le16(t);
> +		ep->file_modify_date = cpu_to_le16(d);
> +		break;
> +	case TM_ACCESS:
> +		ep->file_access_time = cpu_to_le16(t);
> +		ep->file_access_date = cpu_to_le16(d);
> +		break;
> +	}
> +}
> +
> +static void exfat_init_file_entry(struct super_block *sb,
> +		struct exfat_dentry *ep, unsigned int type)
> +{
> +	struct exfat_timestamp tm, *tp;
> +
> +	exfat_set_entry_type(ep, type);
> +
> +	tp = exfat_tm_now(EXFAT_SB(sb), &tm);
> +	exfat_set_entry_time(ep, tp, TM_CREATE);
> +	exfat_set_entry_time(ep, tp, TM_MODIFY);
> +	exfat_set_entry_time(ep, tp, TM_ACCESS);
> +	ep->file_create_time_ms = 0;
> +	ep->file_modify_time_ms = 0;
> +	ep->file_access_time_ms = 0;
> +}
> +
> +static void exfat_init_stream_entry(struct exfat_dentry *ep,
> +		unsigned char flags, unsigned int start_clu,
> +		unsigned long long size)
> +{
> +	exfat_set_entry_type(ep, TYPE_STREAM);
> +	ep->stream_flags = flags;
> +	ep->stream_start_clu = cpu_to_le32(start_clu);
> +	ep->stream_valid_size = cpu_to_le64(size);
> +	ep->stream_size = cpu_to_le64(size);
> +}
> +
> +static void exfat_init_name_entry(struct exfat_dentry *ep,
> +		unsigned short *uniname)
> +{
> +	int i;
> +
> +	exfat_set_entry_type(ep, TYPE_EXTEND);
> +	ep->name_flags = 0x0;
> +
> +	for (i = 0; i < 15; i++) {

Why 15? What does 15 means here?

> +		ep->name_unicode[i] = cpu_to_le16(*uniname);
> +		if (*uniname == 0x0)
> +			break;
> +		uniname++;
> +	}
> +}
> +
> +int exfat_init_dir_entry(struct inode *inode, struct exfat_chain
> *p_dir,
> +		int entry, unsigned int type, unsigned int start_clu,
> +		unsigned long long size)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	sector_t sector;
> +	unsigned char flags;
> +	struct exfat_dentry *ep;
> +	struct buffer_head *bh;
> +	int sync = IS_DIRSYNC(inode);
> +
> +	flags = (type == TYPE_FILE) ? ALLOC_FAT_CHAIN :
> ALLOC_NO_FAT_CHAIN;
> +
> +	/*
> +	 * We cannot use exfat_get_dentry_set here because file ep is
> not
> +	 * initialized yet.
> +	 */
> +	ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
> +	if (!ep)
> +		return -EIO;
> +
> +	exfat_init_file_entry(sb, ep, type);
> +	exfat_update_bh(sb, bh, sync);
> +	brelse(bh);
> +
> +	ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
> +	if (!ep)
> +		return -EIO;
> +
> +	exfat_init_stream_entry(ep, flags, start_clu, size);
> +	exfat_update_bh(sb, bh, sync);
> +	brelse(bh);
> +
> +	return 0;
> +}
> +
> +int update_dir_chksum(struct inode *inode, struct exfat_chain
> *p_dir,
> +		int entry)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	int ret = 0;
> +	int i, num_entries;
> +	sector_t sector;
> +	unsigned short chksum;
> +	struct exfat_dentry *ep, *fep;
> +	struct buffer_head *fbh, *bh;
> +
> +	fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
> +	if (!fep)
> +		return -EIO;
> +
> +	num_entries = fep->file_num_ext + 1;
> +	chksum = exfat_calc_chksum_2byte(fep, DENTRY_SIZE, 0,
> CS_DIR_ENTRY);
> +
> +	for (i = 1; i < num_entries; i++) {
> +		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
> +		if (!ep) {
> +			ret = -EIO;
> +			goto release_fbh;
> +		}
> +		chksum = exfat_calc_chksum_2byte(ep, DENTRY_SIZE,
> chksum,
> +				CS_DEFAULT);
> +		brelse(bh);
> +	}
> +
> +	fep->file_checksum = cpu_to_le16(chksum);
> +	exfat_update_bh(sb, fbh, IS_DIRSYNC(inode));
> +release_fbh:
> +	brelse(fbh);
> +	return ret;
> +}
> +
> +int exfat_init_ext_entry(struct inode *inode, struct exfat_chain
> *p_dir,
> +		int entry, int num_entries, struct exfat_uni_name
> *p_uniname)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	int i;
> +	sector_t sector;
> +	unsigned short *uniname = p_uniname->name;
> +	struct exfat_dentry *ep;
> +	struct buffer_head *bh;
> +	int sync = IS_DIRSYNC(inode);
> +
> +	ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
> +	if (!ep)
> +		return -EIO;
> +
> +	ep->file_num_ext = (unsigned char)(num_entries - 1);
> +	exfat_update_bh(sb, bh, sync);
> +	brelse(bh);
> +
> +	ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
> +	if (!ep)
> +		return -EIO;
> +
> +	ep->stream_name_len = p_uniname->name_len;
> +	ep->stream_name_hash = cpu_to_le16(p_uniname->name_hash);
> +	exfat_update_bh(sb, bh, sync);
> +	brelse(bh);
> +
> +	for (i = 2; i < num_entries; i++) {

I believe it needs to comment why the cycle starts with i equals to 2.

> +		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh,
> &sector);
> +		if (!ep)
> +			return -EIO;
> +
> +		exfat_init_name_entry(ep, uniname);
> +		exfat_update_bh(sb, bh, sync);
> +		brelse(bh);
> +		uniname += 15;

What does 15 means here?

> +	}
> +
> +	update_dir_chksum(inode, p_dir, entry);
> +	return 0;
> +}
> +
> +int exfat_remove_entries(struct inode *inode, struct exfat_chain
> *p_dir,
> +		int entry, int order, int num_entries)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	int i;
> +	sector_t sector;
> +	struct exfat_dentry *ep;
> +	struct buffer_head *bh;
> +
> +	for (i = order; i < num_entries; i++) {
> +		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh,
> &sector);
> +		if (!ep)
> +			return -EIO;
> +
> +		exfat_set_entry_type(ep, TYPE_DELETED);
> +		exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
> +		brelse(bh);
> +	}
> +
> +	return 0;
> +}
> +
> +int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
> +		struct exfat_entry_set_cache *es, int sync)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +	sector_t sec = es->sector;
> +	unsigned int off = es->offset;
> +	int chksum_type = CS_DIR_ENTRY, i, num_entries = es-
> >num_entries;
> +	unsigned int buf_off = (off - es->offset);
> +	unsigned int remaining_byte_in_sector, copy_entries, clu;
> +	unsigned short chksum = 0;
> +
> +	for (i = 0; i < num_entries; i++) {
> +		chksum = exfat_calc_chksum_2byte(&es->entries[i],
> DENTRY_SIZE,
> +			chksum, chksum_type);
> +		chksum_type = CS_DEFAULT;
> +	}
> +
> +	es->entries[0].file_checksum = cpu_to_le16(chksum);
> +
> +	while (num_entries) {
> +		/* write per sector base */
> +		remaining_byte_in_sector = (1 << sb->s_blocksize_bits)
> - off;
> +		copy_entries = min_t(int,
> +			EXFAT_B_TO_DEN(remaining_byte_in_sector),
> +			num_entries);
> +		bh = sb_bread(sb, sec);
> +		if (!bh)
> +			goto err_out;
> +		memcpy(bh->b_data + off,
> +			(unsigned char *)&es->entries[0] + buf_off,
> +			EXFAT_DEN_TO_B(copy_entries));
> +		exfat_update_bh(sb, bh, sync);
> +		brelse(bh);
> +		num_entries -= copy_entries;
> +
> +		if (num_entries) {
> +			/* get next sector */
> +			if (exfat_is_last_sector_in_cluster(sbi, sec))
> {
> +				clu = exfat_sector_to_cluster(sbi,
> sec);
> +				if (es->alloc_flag ==
> ALLOC_NO_FAT_CHAIN)
> +					clu++;
> +				else if (exfat_get_next_cluster(sb,
> &clu))
> +					goto err_out;
> +				sec = exfat_cluster_to_sector(sbi,
> clu);
> +			} else {
> +				sec++;
> +			}
> +			off = 0;
> +			buf_off += EXFAT_DEN_TO_B(copy_entries);
> +		}
> +	}
> +
> +	return 0;
> +err_out:
> +	return -EIO;
> +}
> +
> +static int exfat_walk_fat_chain(struct super_block *sb,
> +		struct exfat_chain *p_dir, unsigned int byte_offset,
> +		unsigned int *clu)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	unsigned int clu_offset;
> +	unsigned int cur_clu;
> +
> +	clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
> +	cur_clu = p_dir->dir;
> +
> +	if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
> +		cur_clu += clu_offset;
> +	} else {
> +		while (clu_offset > 0) {
> +			if (exfat_get_next_cluster(sb, &cur_clu))
> +				return -EIO;
> +			if (cur_clu == EOF_CLUSTER) {
> +				exfat_fs_error(sb,
> +					"invalid dentry access beyond
> EOF (clu : %u, eidx : %d)",
> +					p_dir->dir,
> +					EXFAT_B_TO_DEN(byte_offset));
> +				return -EIO;
> +			}
> +			clu_offset--;
> +		}
> +	}
> +
> +	*clu = cur_clu;
> +	return 0;
> +}
> +
> +int exfat_find_location(struct super_block *sb, struct exfat_chain
> *p_dir,
> +		int entry, sector_t *sector, int *offset)
> +{
> +	int ret;
> +	unsigned int off, clu = 0;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	off = EXFAT_DEN_TO_B(entry);
> +
> +	ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
> +	if (ret)
> +		return ret;
> +
> +	/* byte offset in cluster */
> +	off = EXFAT_CLU_OFFSET(off, sbi);
> +
> +	/* byte offset in sector    */
> +	*offset = EXFAT_BLK_OFFSET(off, sb);
> +
> +	/* sector offset in cluster */
> +	*sector = EXFAT_B_TO_BLK(off, sb);
> +	*sector += exfat_cluster_to_sector(sbi, clu);
> +	return 0;
> +}
> +
> +#define EXFAT_MAX_RA_SIZE     (128*1024)
> +static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +	unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb-
> >s_blocksize_bits;
> +	unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
> +	unsigned int adj_ra_count = max(sbi->sect_per_clus,
> page_ra_count);
> +	unsigned int ra_count = min(adj_ra_count, max_ra_count);
> +
> +	/* Read-ahead is not required */
> +	if (sbi->sect_per_clus == 1)
> +		return 0;
> +
> +	if (sec < sbi->data_start_sector) {
> +		exfat_msg(sb, KERN_ERR,
> +			"requested sector is invalid(sect:%llu,
> root:%llu)",
> +			sec, sbi->data_start_sector);
> +		return -EIO;
> +	}
> +
> +	/* Not sector aligned with ra_count, resize ra_count to page
> size */
> +	if ((sec - sbi->data_start_sector) & (ra_count - 1))
> +		ra_count = page_ra_count;
> +
> +	bh = sb_find_get_block(sb, sec);
> +	if (!bh || !buffer_uptodate(bh)) {
> +		unsigned int i;
> +
> +		for (i = 0; i < ra_count; i++)
> +			sb_breadahead(sb, (sector_t)(sec + i));
> +	}
> +	brelse(bh);
> +	return 0;
> +}
> +
> +struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
> +		struct exfat_chain *p_dir, int entry, struct
> buffer_head **bh,
> +		sector_t *sector)
> +{
> +	unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
> +	int off;
> +	sector_t sec;
> +
> +	if (p_dir->dir == DIR_DELETED) {
> +		exfat_msg(sb, KERN_ERR, "abnormal access to deleted
> dentry\n");
> +		return NULL;
> +	}
> +
> +	if (exfat_find_location(sb, p_dir, entry, &sec, &off))
> +		return NULL;
> +
> +	if (p_dir->dir != FREE_CLUSTER &&
> +			!(entry & (dentries_per_page - 1)))
> +		exfat_dir_readahead(sb, sec);
> +
> +	*bh = sb_bread(sb, sec);
> +	if (!*bh)
> +		return NULL;
> +
> +	if (sector)
> +		*sector = sec;
> +	return (struct exfat_dentry *)((*bh)->b_data + off);
> +}
> +
> +enum exfat_validate_dentry_mode {
> +	ES_MODE_STARTED,
> +	ES_MODE_GET_FILE_ENTRY,
> +	ES_MODE_GET_STRM_ENTRY,
> +	ES_MODE_GET_NAME_ENTRY,
> +	ES_MODE_GET_CRITICAL_SEC_ENTRY,
> +};
> +
> +static bool exfat_validate_entry(unsigned int type,
> +		enum exfat_validate_dentry_mode *mode)
> +{
> +	if (type == TYPE_UNUSED || type == TYPE_DELETED)
> +		return false;
> +
> +	switch (*mode) {
> +	case ES_MODE_STARTED:
> +		if  (type != TYPE_FILE && type != TYPE_DIR)
> +			return false;
> +		*mode = ES_MODE_GET_FILE_ENTRY;
> +		return true;
> +	case ES_MODE_GET_FILE_ENTRY:
> +		if (type != TYPE_STREAM)
> +			return false;
> +		*mode = ES_MODE_GET_STRM_ENTRY;
> +		return true;
> +	case ES_MODE_GET_STRM_ENTRY:
> +		if (type != TYPE_EXTEND)
> +			return false;
> +		*mode = ES_MODE_GET_NAME_ENTRY;
> +		return true;
> +	case ES_MODE_GET_NAME_ENTRY:
> +		if (type == TYPE_STREAM)
> +			return false;
> +		if (type != TYPE_EXTEND) {
> +			if (!(type & TYPE_CRITICAL_SEC))
> +				return false;
> +			*mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
> +		}
> +		return true;
> +	case ES_MODE_GET_CRITICAL_SEC_ENTRY:
> +		if (type == TYPE_EXTEND || type == TYPE_STREAM)
> +			return false;
> +		if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
> +			return false;
> +		return true;
> +	default:
> +		WARN_ON_ONCE(1);
> +		return false;
> +	}
> +}
> +
> +/*
> + * Returns a set of dentries for a file or dir.
> + *
> + * Note that this is a copy (dump) of dentries so that user should
> + * call write_entry_set() to apply changes made in this entry set
> + * to the real device.
> + *
> + * in:
> + *   sb+p_dir+entry: indicates a file/dir
> + *   type:  specifies how many dentries should be included.
> + * out:
> + *   file_ep: will point the first dentry(= file dentry) on success
> + * return:
> + *   pointer of entry set on success,
> + *   NULL on failure.
> + */
> +struct exfat_entry_set_cache *exfat_get_dentry_set(struct
> super_block *sb,
> +		struct exfat_chain *p_dir, int entry, unsigned int
> type,
> +		struct exfat_dentry **file_ep)
> +{
> +	int ret;
> +	unsigned int off, byte_offset, clu = 0;
> +	unsigned int entry_type;
> +	sector_t sec;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_entry_set_cache *es;
> +	struct exfat_dentry *ep, *pos;
> +	unsigned char num_entries;
> +	enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
> +	struct buffer_head *bh;
> +
> +	if (p_dir->dir == DIR_DELETED) {
> +		exfat_msg(sb, KERN_ERR, "access to deleted dentry\n");
> +		return NULL;
> +	}
> +
> +	byte_offset = EXFAT_DEN_TO_B(entry);
> +	ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
> +	if (ret)
> +		return NULL;
> +
> +	/* byte offset in cluster */
> +	byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
> +
> +	/* byte offset in sector */
> +	off = EXFAT_BLK_OFFSET(byte_offset, sb);
> +
> +	/* sector offset in cluster */
> +	sec = EXFAT_B_TO_BLK(byte_offset, sb);
> +	sec += exfat_cluster_to_sector(sbi, clu);
> +
> +	bh = sb_bread(sb, sec);
> +	if (!bh)
> +		return NULL;
> +
> +	ep = (struct exfat_dentry *)(bh->b_data + off);
> +	entry_type = exfat_get_entry_type(ep);
> +
> +	if (entry_type != TYPE_FILE && entry_type != TYPE_DIR)
> +		goto release_bh;
> +
> +	num_entries = type == ES_ALL_ENTRIES ? ep->file_num_ext + 1 :
> type;
> +	es = kmalloc(struct_size(es, entries, num_entries),
> GFP_KERNEL);
> +	if (!es)
> +		goto release_bh;
> +
> +	es->num_entries = num_entries;
> +	es->sector = sec;
> +	es->offset = off;
> +	es->alloc_flag = p_dir->flags;
> +
> +	pos = &es->entries[0];
> +
> +	while (num_entries) {
> +		if (!exfat_validate_entry(exfat_get_entry_type(ep),
> &mode))
> +			goto free_es;
> +
> +		/* copy dentry */
> +		memcpy(pos, ep, sizeof(struct exfat_dentry));
> +
> +		if (--num_entries == 0)
> +			break;
> +
> +		if (((off + DENTRY_SIZE) & (sb->s_blocksize - 1)) <
> +		    (off & (sb->s_blocksize - 1))) {
> +			/* get the next sector */
> +			if (exfat_is_last_sector_in_cluster(sbi, sec))
> {
> +				if (es->alloc_flag ==
> ALLOC_NO_FAT_CHAIN)
> +					clu++;
> +				else if (exfat_get_next_cluster(sb,
> &clu))
> +					goto free_es;
> +				sec = exfat_cluster_to_sector(sbi,
> clu);
> +			} else {
> +				sec++;
> +			}
> +
> +			brelse(bh);
> +			bh = sb_bread(sb, sec);
> +			if (!bh)
> +				goto free_es;
> +			off = 0;
> +			ep = (struct exfat_dentry *)bh->b_data;
> +		} else {
> +			ep++;
> +			off += DENTRY_SIZE;
> +		}
> +		pos++;
> +	}
> +
> +	if (file_ep)
> +		*file_ep = &es->entries[0];
> +	brelse(bh);
> +	return es;
> +
> +free_es:
> +	kfree(es);
> +release_bh:
> +	brelse(bh);
> +	return NULL;
> +}
> +
> +static int exfat_extract_uni_name(struct exfat_dentry *ep,
> +		unsigned short *uniname)
> +{
> +	int i, len = 0;
> +
> +	for (i = 0; i < 15; i++) {

Ditto. What does 15 means here?

> +		*uniname = le16_to_cpu(ep->name_unicode[i]);
> +		if (*uniname == 0x0)
> +			return len;
> +		uniname++;
> +		len++;
> +	}
> +
> +	*uniname = 0x0;
> +	return len;
> +
> +}
> +
> +enum {
> +	DIRENT_STEP_FILE,
> +	DIRENT_STEP_STRM,
> +	DIRENT_STEP_NAME,
> +	DIRENT_STEP_SECD,
> +};
> +
> +/*
> + * return values:
> + *   >= 0	: return dir entiry position with the name in dir
> + *   -EEXIST	: (root dir, ".") it is the root dir itself
> + *   -ENOENT	: entry with the name does not exist
> + *   -EIO	: I/O error
> + */
> +int exfat_find_dir_entry(struct super_block *sb, struct
> exfat_inode_info *ei,
> +		struct exfat_chain *p_dir, struct exfat_uni_name
> *p_uniname,
> +		int num_entries, unsigned int type)
> +{
> +	int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
> +	int order, step, name_len = 0;
> +	int dentries_per_clu, num_empty = 0;
> +	unsigned int entry_type;
> +	unsigned short *uniname = NULL;
> +	struct exfat_chain clu;
> +	struct exfat_hint *hint_stat = &ei->hint_stat;
> +	struct exfat_hint_femp candi_empty;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	dentries_per_clu = sbi->dentries_per_clu;
> +
> +	exfat_chain_dup(&clu, p_dir);
> +
> +	if (hint_stat->eidx) {
> +		clu.dir = hint_stat->clu;
> +		dentry = hint_stat->eidx;
> +		end_eidx = dentry;
> +	}
> +
> +	candi_empty.eidx = EXFAT_HINT_NONE;
> +rewind:
> +	order = 0;
> +	step = DIRENT_STEP_FILE;
> +	while (clu.dir != EOF_CLUSTER) {
> +		i = dentry & (dentries_per_clu - 1);
> +		for (; i < dentries_per_clu; i++, dentry++) {
> +			struct exfat_dentry *ep;
> +			struct buffer_head *bh;
> +
> +			if (rewind && dentry == end_eidx)
> +				goto not_found;
> +
> +			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
> +			if (!ep)
> +				return -EIO;
> +
> +			entry_type = exfat_get_entry_type(ep);
> +
> +			if (entry_type == TYPE_UNUSED ||
> +			    entry_type == TYPE_DELETED) {
> +				step = DIRENT_STEP_FILE;
> +
> +				num_empty++;
> +				if (candi_empty.eidx == EXFAT_HINT_NONE
> &&
> +						num_empty == 1) {
> +					exfat_chain_set(&candi_empty.cu
> r,
> +						clu.dir, clu.size,
> clu.flags);
> +				}
> +
> +				if (candi_empty.eidx == EXFAT_HINT_NONE
> &&
> +						num_empty >=
> num_entries) {
> +					candi_empty.eidx =
> +						dentry - (num_empty -
> 1);
> +					WARN_ON(candi_empty.eidx < 0);
> +					candi_empty.count = num_empty;
> +
> +					if (ei->hint_femp.eidx ==
> +							EXFAT_HINT_NONE
> ||
> +						candi_empty.eidx <=
> +							 ei-
> >hint_femp.eidx) {
> +						memcpy(&ei->hint_femp,
> +							&candi_empty,
> +							sizeof(candi_em
> pty));
> +					}
> +				}
> +
> +				brelse(bh);
> +				if (entry_type == TYPE_UNUSED)
> +					goto not_found;
> +				continue;
> +			}
> +
> +			num_empty = 0;
> +			candi_empty.eidx = EXFAT_HINT_NONE;
> +
> +			if (entry_type == TYPE_FILE || entry_type ==
> TYPE_DIR) {
> +				step = DIRENT_STEP_FILE;
> +				if (type == TYPE_ALL || type ==
> entry_type) {
> +					num_ext = ep->file_num_ext;
> +					step = DIRENT_STEP_STRM;
> +				}
> +				brelse(bh);
> +				continue;
> +			}
> +
> +			if (entry_type == TYPE_STREAM) {
> +				unsigned short name_hash;
> +
> +				if (step != DIRENT_STEP_STRM) {
> +					step = DIRENT_STEP_FILE;
> +					brelse(bh);
> +					continue;
> +				}
> +				step = DIRENT_STEP_FILE;
> +				name_hash = le16_to_cpu(ep-
> >stream_name_hash);
> +				if (p_uniname->name_hash == name_hash
> &&
> +				    p_uniname->name_len ==
> +						ep->stream_name_len) {
> +					step = DIRENT_STEP_NAME;
> +					order = 1;
> +					name_len = 0;
> +				}
> +				brelse(bh);
> +				continue;
> +			}
> +
> +			brelse(bh);
> +			if (entry_type == TYPE_EXTEND) {
> +				unsigned short entry_uniname[16],
> unichar;
> +
> +				if (step != DIRENT_STEP_NAME) {
> +					step = DIRENT_STEP_FILE;
> +					continue;
> +				}
> +
> +				if (++order == 2)
> +					uniname = p_uniname->name;
> +				else
> +					uniname += 15;

Ditto. What does 15 mean here?

> +
> +				len = exfat_extract_uni_name(
> +						ep, entry_uniname);
> +				name_len += len;
> +
> +				unichar = *(uniname+len);
> +				*(uniname+len) = 0x0;
> +
> +				if (exfat_nls_cmp_uniname(sb, uniname,
> +							entry_uniname))
> {
> +					step = DIRENT_STEP_FILE;
> +				} else if (name_len == p_uniname-
> >name_len) {
> +					if (order == num_ext)
> +						goto found;
> +					step = DIRENT_STEP_SECD;
> +				}
> +
> +				*(uniname+len) = unichar;
> +				continue;
> +			}
> +
> +			if (entry_type &
> +					(TYPE_CRITICAL_SEC |
> TYPE_BENIGN_SEC)) {
> +				if (step == DIRENT_STEP_SECD) {
> +					if (++order == num_ext)
> +						goto found;
> +					continue;
> +				}
> +			}
> +			step = DIRENT_STEP_FILE;
> +		}
> +
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			if (--clu.size > 0)
> +				clu.dir++;
> +			else
> +				clu.dir = EOF_CLUSTER;
> +		} else {
> +			if (exfat_get_next_cluster(sb, &clu.dir))
> +				return -EIO;
> +		}
> +	}
> +
> +not_found:
> +	/*
> +	 * We started at not 0 index,so we should try to find target
> +	 * from 0 index to the index we started at.
> +	 */
> +	if (!rewind && end_eidx) {
> +		rewind = 1;
> +		dentry = 0;
> +		clu.dir = p_dir->dir;
> +		/* reset empty hint */
> +		num_empty = 0;
> +		candi_empty.eidx = EXFAT_HINT_NONE;
> +		goto rewind;
> +	}
> +
> +	/* initialized hint_stat */
> +	hint_stat->clu = p_dir->dir;
> +	hint_stat->eidx = 0;
> +	return -ENOENT;
> +
> +found:
> +	/* next dentry we'll find is out of this cluster */
> +	if (!((dentry + 1) & (dentries_per_clu - 1))) {
> +		int ret = 0;
> +
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			if (--clu.size > 0)
> +				clu.dir++;
> +			else
> +				clu.dir = EOF_CLUSTER;
> +		} else {
> +			ret = exfat_get_next_cluster(sb, &clu.dir);
> +		}
> +
> +		if (ret || clu.dir != EOF_CLUSTER) {
> +			/* just initialized hint_stat */
> +			hint_stat->clu = p_dir->dir;
> +			hint_stat->eidx = 0;
> +			return (dentry - num_ext);
> +		}
> +	}
> +
> +	hint_stat->clu = clu.dir;
> +	hint_stat->eidx = dentry + 1;
> +	return dentry - num_ext;
> +}
> +
> +int exfat_count_ext_entries(struct super_block *sb, struct
> exfat_chain *p_dir,
> +		int entry, struct exfat_dentry *ep)
> +{
> +	int i, count = 0;
> +	unsigned int type;
> +	struct exfat_dentry *ext_ep;
> +	struct buffer_head *bh;
> +
> +	for (i = 0, entry++; i < ep->file_num_ext; i++, entry++) {
> +		ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
> +		if (!ext_ep)
> +			return -EIO;
> +
> +		type = exfat_get_entry_type(ext_ep);
> +		brelse(bh);
> +		if (type == TYPE_EXTEND || type == TYPE_STREAM)
> +			count++;
> +		else
> +			break;
> +	}
> +	return count;
> +}
> +
> +void exfat_get_uniname_from_ext_entry(struct super_block *sb,
> +		struct exfat_chain *p_dir, int entry, unsigned short
> *uniname)
> +{
> +	int i;
> +	struct exfat_dentry *ep;
> +	struct exfat_entry_set_cache *es;
> +
> +	es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES,
> &ep);
> +	if (!es)
> +		return;
> +
> +	if (es->num_entries < 3)
> +		goto free_es;
> +
> +	ep += 2;

Potentially, ep could point out the garbage here!!!!

> +
> +	/*
> +	 * First entry  : file entry
> +	 * Second entry : stream-extension entry
> +	 * Third entry  : first file-name entry
> +	 * So, the index of first file-name dentry should start from 2.
> +	 */
> +	for (i = 2; i < es->num_entries; i++, ep++) {
> +		/* end of name entry */
> +		if (exfat_get_entry_type(ep) != TYPE_EXTEND)
> +			goto free_es;
> +
> +		exfat_extract_uni_name(ep, uniname);
> +		uniname += 15;

Ditto. What does 15 mean here?

Thanks,
Viacheslav Dubeyko.

> +	}
> +
> +free_es:
> +	kfree(es);
> +}
> +
> +int exfat_count_dir_entries(struct super_block *sb, struct
> exfat_chain *p_dir)
> +{
> +	int i, count = 0;
> +	int dentries_per_clu;
> +	unsigned int entry_type;
> +	struct exfat_chain clu;
> +	struct exfat_dentry *ep;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +
> +	dentries_per_clu = sbi->dentries_per_clu;
> +
> +	exfat_chain_dup(&clu, p_dir);
> +
> +	while (clu.dir != EOF_CLUSTER) {
> +		for (i = 0; i < dentries_per_clu; i++) {
> +			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
> +			if (!ep)
> +				return -EIO;
> +			entry_type = exfat_get_entry_type(ep);
> +			brelse(bh);
> +
> +			if (entry_type == TYPE_UNUSED)
> +				return count;
> +			if (entry_type != TYPE_DIR)
> +				continue;
> +			count++;
> +		}
> +
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			if (--clu.size > 0)
> +				clu.dir++;
> +			else
> +				clu.dir = EOF_CLUSTER;
> +		} else {
> +			if (exfat_get_next_cluster(sb, &(clu.dir)))
> +				return -EIO;
> +		}
> +	}
> +
> +	return count;
> +}

[PATCH v6 05/13] exfat: add file operations

[Namjae Jeon]

This adds the implementation of file operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/file.c | 343 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 343 insertions(+)
 create mode 100644 fs/exfat/file.c

diff --git a/fs/exfat/file.c b/fs/exfat/file.c
new file mode 100644
index 000000000000..1a32a88e2055
--- /dev/null
+++ b/fs/exfat/file.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static int exfat_cont_expand(struct inode *inode, loff_t size)
+{
+	struct address_space *mapping = inode->i_mapping;
+	loff_t start = i_size_read(inode), count = size - i_size_read(inode);
+	int err, err2;
+
+	err = generic_cont_expand_simple(inode, size);
+	if (err)
+		return err;
+
+	inode->i_ctime = inode->i_mtime = current_time(inode);
+	mark_inode_dirty(inode);
+
+	if (!IS_SYNC(inode))
+		return 0;
+
+	err = filemap_fdatawrite_range(mapping, start, start + count - 1);
+	err2 = sync_mapping_buffers(mapping);
+	if (!err)
+		err = err2;
+	err2 = write_inode_now(inode, 1);
+	if (!err)
+		err = err2;
+	if (err)
+		return err;
+
+	return filemap_fdatawait_range(mapping, start, start + count - 1);
+}
+
+static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
+{
+	mode_t allow_utime = sbi->options.allow_utime;
+
+	if (!uid_eq(current_fsuid(), inode->i_uid)) {
+		if (in_group_p(inode->i_gid))
+			allow_utime >>= 3;
+		if (allow_utime & MAY_WRITE)
+			return true;
+	}
+
+	/* use a default check */
+	return false;
+}
+
+static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
+		struct inode *inode, umode_t *mode_ptr)
+{
+	mode_t i_mode, mask, perm;
+
+	i_mode = inode->i_mode;
+
+	mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
+		sbi->options.fs_fmask : sbi->options.fs_dmask;
+	perm = *mode_ptr & ~(S_IFMT | mask);
+
+	/* Of the r and x bits, all (subject to umask) must be present.*/
+	if ((perm & 0555) != (i_mode & 0555))
+		return -EPERM;
+
+	if (exfat_mode_can_hold_ro(inode)) {
+		/*
+		 * Of the w bits, either all (subject to umask) or none must
+		 * be present.
+		 */
+		if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
+			return -EPERM;
+	} else {
+		/*
+		 * If exfat_mode_can_hold_ro(inode) is false, can't change
+		 * w bits.
+		 */
+		if ((perm & 0222) != (0222 & ~mask))
+			return -EPERM;
+	}
+
+	*mode_ptr &= S_IFMT | perm;
+
+	return 0;
+}
+
+/* resize the file length */
+int __exfat_truncate(struct inode *inode, loff_t new_size)
+{
+	unsigned int num_clusters_new, num_clusters_phys;
+	unsigned int last_clu = FREE_CLUSTER;
+	struct exfat_chain clu;
+	struct exfat_timestamp tm;
+	struct exfat_dentry *ep, *ep2;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_entry_set_cache *es = NULL;
+	int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
+
+	/* check if the given file ID is opened */
+	if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
+		return -EPERM;
+
+	exfat_set_vol_flags(sb, VOL_DIRTY);
+
+	num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
+	num_clusters_phys =
+		EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->i_size_ondisk, sbi);
+
+	exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
+
+	if (new_size > 0) {
+		/*
+		 * Truncate FAT chain num_clusters after the first cluster
+		 * num_clusters = min(new, phys);
+		 */
+		unsigned int num_clusters =
+			min(num_clusters_new, num_clusters_phys);
+
+		/*
+		 * Follow FAT chain
+		 * (defensive coding - works fine even with corrupted FAT table
+		 */
+		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
+			clu.dir += num_clusters;
+			clu.size -= num_clusters;
+		} else {
+			while (num_clusters > 0) {
+				last_clu = clu.dir;
+				if (exfat_get_next_cluster(sb, &(clu.dir)))
+					return -EIO;
+
+				num_clusters--;
+				clu.size--;
+			}
+		}
+	} else {
+		ei->flags = ALLOC_NO_FAT_CHAIN;
+		ei->start_clu = EOF_CLUSTER;
+	}
+
+	i_size_write(inode, new_size);
+
+	if (ei->type == TYPE_FILE)
+		ei->attr |= ATTR_ARCHIVE;
+
+	/* update the directory entry */
+	if (!evict) {
+		es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
+				ES_ALL_ENTRIES, &ep);
+		if (!es)
+			return -EIO;
+		ep2 = ep + 1;
+
+		exfat_set_entry_time(ep, exfat_tm_now(EXFAT_SB(sb), &tm),
+				TM_MODIFY);
+		ep->file_attr = cpu_to_le16(ei->attr);
+
+		/* File size should be zero if there is no cluster allocated */
+		if (ei->start_clu == EOF_CLUSTER)
+			ep->stream_valid_size = ep->stream_size = 0;
+		else {
+			ep->stream_valid_size = cpu_to_le64(new_size);
+			ep->stream_size = ep->stream_valid_size;
+		}
+
+		if (new_size == 0) {
+			/* Any directory can not be truncated to zero */
+			WARN_ON(ei->type != TYPE_FILE);
+
+			ep2->stream_flags = ALLOC_FAT_CHAIN;
+			ep2->stream_start_clu = FREE_CLUSTER;
+		}
+
+		if (exfat_update_dir_chksum_with_entry_set(sb, es,
+		    inode_needs_sync(inode)))
+			return -EIO;
+		kfree(es);
+	}
+
+	/* cut off from the FAT chain */
+	if (ei->flags == ALLOC_FAT_CHAIN && last_clu != FREE_CLUSTER &&
+			last_clu != EOF_CLUSTER) {
+		if (exfat_ent_set(sb, last_clu, EOF_CLUSTER))
+			return -EIO;
+	}
+
+	/* invalidate cache and free the clusters */
+	/* clear exfat cache */
+	exfat_cache_inval_inode(inode);
+
+	/* hint information */
+	ei->hint_bmap.off = EOF_CLUSTER;
+	ei->hint_bmap.clu = EOF_CLUSTER;
+	if (ei->rwoffset > new_size)
+		ei->rwoffset = new_size;
+
+	/* hint_stat will be used if this is directory. */
+	ei->hint_stat.eidx = 0;
+	ei->hint_stat.clu = ei->start_clu;
+	ei->hint_femp.eidx = EXFAT_HINT_NONE;
+
+	/* free the clusters */
+	if (exfat_free_cluster(inode, &clu))
+		return -EIO;
+
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+
+	return 0;
+}
+
+void exfat_truncate(struct inode *inode, loff_t size)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int blocksize = 1 << inode->i_blkbits;
+	loff_t aligned_size;
+	int err;
+
+	mutex_lock(&sbi->s_lock);
+	if (EXFAT_I(inode)->start_clu == 0) {
+		/*
+		 * Empty start_clu != ~0 (not allocated)
+		 */
+		exfat_fs_error(sb, "tried to truncate zeroed cluster.");
+		goto write_size;
+	}
+
+	err = __exfat_truncate(inode, i_size_read(inode));
+	if (err)
+		goto write_size;
+
+	inode->i_ctime = inode->i_mtime = current_time(inode);
+	if (IS_DIRSYNC(inode))
+		exfat_sync_inode(inode);
+	else
+		mark_inode_dirty(inode);
+
+	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) &
+			~(sbi->cluster_size - 1)) >> inode->i_blkbits;
+write_size:
+	aligned_size = i_size_read(inode);
+	if (aligned_size & (blocksize - 1)) {
+		aligned_size |= (blocksize - 1);
+		aligned_size++;
+	}
+
+	if (EXFAT_I(inode)->i_size_ondisk > i_size_read(inode))
+		EXFAT_I(inode)->i_size_ondisk = aligned_size;
+
+	if (EXFAT_I(inode)->i_size_aligned > i_size_read(inode))
+		EXFAT_I(inode)->i_size_aligned = aligned_size;
+	mutex_unlock(&sbi->s_lock);
+}
+
+int exfat_getattr(const struct path *path, struct kstat *stat,
+		unsigned int request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_backing_inode(path->dentry);
+
+	generic_fillattr(inode, stat);
+	stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
+	return 0;
+}
+
+int exfat_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
+	struct inode *inode = dentry->d_inode;
+	unsigned int ia_valid;
+	int error;
+
+	if ((attr->ia_valid & ATTR_SIZE) &&
+	    attr->ia_size > i_size_read(inode)) {
+		error = exfat_cont_expand(inode, attr->ia_size);
+		if (error || attr->ia_valid == ATTR_SIZE)
+			return error;
+		attr->ia_valid &= ~ATTR_SIZE;
+	}
+
+	/* Check for setting the inode time. */
+	ia_valid = attr->ia_valid;
+	if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
+	    exfat_allow_set_time(sbi, inode)) {
+		attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
+				ATTR_TIMES_SET);
+	}
+
+	error = setattr_prepare(dentry, attr);
+	attr->ia_valid = ia_valid;
+	if (error)
+		return error;
+
+	if (((attr->ia_valid & ATTR_UID) &&
+	     !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
+	    ((attr->ia_valid & ATTR_GID) &&
+	     !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
+	    ((attr->ia_valid & ATTR_MODE) &&
+	     (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777))))
+		return -EPERM;
+
+	/*
+	 * We don't return -EPERM here. Yes, strange, but this is too
+	 * old behavior.
+	 */
+	if (attr->ia_valid & ATTR_MODE) {
+		if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
+			attr->ia_valid &= ~ATTR_MODE;
+	}
+
+	if (attr->ia_valid & ATTR_SIZE) {
+		down_write(&EXFAT_I(inode)->truncate_lock);
+		truncate_setsize(inode, attr->ia_size);
+		exfat_truncate(inode, attr->ia_size);
+		up_write(&EXFAT_I(inode)->truncate_lock);
+	}
+
+	setattr_copy(inode, attr);
+	mark_inode_dirty(inode);
+
+	return error;
+}
+
+const struct file_operations exfat_file_operations = {
+	.llseek      = generic_file_llseek,
+	.read_iter   = generic_file_read_iter,
+	.write_iter  = generic_file_write_iter,
+	.mmap        = generic_file_mmap,
+	.fsync       = generic_file_fsync,
+	.splice_read = generic_file_splice_read,
+};
+
+const struct inode_operations exfat_file_inode_operations = {
+	.setattr     = exfat_setattr,
+	.getattr     = exfat_getattr,
+};
-- 
2.17.1

Re: [PATCH v6 05/13] exfat: add file operations

[Vyacheslav Dubeyko]

On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of file operations for exfat.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
>  fs/exfat/file.c | 343
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 343 insertions(+)
>  create mode 100644 fs/exfat/file.c
> 
> diff --git a/fs/exfat/file.c b/fs/exfat/file.c
> new file mode 100644
> index 000000000000..1a32a88e2055
> --- /dev/null
> +++ b/fs/exfat/file.c
> @@ -0,0 +1,343 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/cred.h>
> +#include <linux/buffer_head.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +static int exfat_cont_expand(struct inode *inode, loff_t size)
> +{
> +	struct address_space *mapping = inode->i_mapping;
> +	loff_t start = i_size_read(inode), count = size -
> i_size_read(inode);
> +	int err, err2;
> +
> +	err = generic_cont_expand_simple(inode, size);
> +	if (err)
> +		return err;
> +
> +	inode->i_ctime = inode->i_mtime = current_time(inode);
> +	mark_inode_dirty(inode);
> +
> +	if (!IS_SYNC(inode))
> +		return 0;
> +
> +	err = filemap_fdatawrite_range(mapping, start, start + count -
> 1);
> +	err2 = sync_mapping_buffers(mapping);
> +	if (!err)
> +		err = err2;
> +	err2 = write_inode_now(inode, 1);
> +	if (!err)
> +		err = err2;
> +	if (err)
> +		return err;
> +
> +	return filemap_fdatawait_range(mapping, start, start + count -
> 1);
> +}
> +
> +static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct
> inode *inode)
> +{
> +	mode_t allow_utime = sbi->options.allow_utime;
> +
> +	if (!uid_eq(current_fsuid(), inode->i_uid)) {
> +		if (in_group_p(inode->i_gid))
> +			allow_utime >>= 3;
> +		if (allow_utime & MAY_WRITE)
> +			return true;
> +	}
> +
> +	/* use a default check */
> +	return false;
> +}
> +
> +static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
> +		struct inode *inode, umode_t *mode_ptr)
> +{
> +	mode_t i_mode, mask, perm;
> +
> +	i_mode = inode->i_mode;
> +
> +	mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
> +		sbi->options.fs_fmask : sbi->options.fs_dmask;
> +	perm = *mode_ptr & ~(S_IFMT | mask);
> +
> +	/* Of the r and x bits, all (subject to umask) must be
> present.*/
> +	if ((perm & 0555) != (i_mode & 0555))

What's about to use constants here instead of hardcoded values?

> +		return -EPERM;
> +
> +	if (exfat_mode_can_hold_ro(inode)) {
> +		/*
> +		 * Of the w bits, either all (subject to umask) or none
> must
> +		 * be present.
> +		 */
> +		if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))

Ditto.

> +			return -EPERM;
> +	} else {
> +		/*
> +		 * If exfat_mode_can_hold_ro(inode) is false, can't
> change
> +		 * w bits.
> +		 */
> +		if ((perm & 0222) != (0222 & ~mask))

Ditto.

> +			return -EPERM;
> +	}
> +
> +	*mode_ptr &= S_IFMT | perm;
> +
> +	return 0;
> +}
> +
> +/* resize the file length */
> +int __exfat_truncate(struct inode *inode, loff_t new_size)
> +{
> +	unsigned int num_clusters_new, num_clusters_phys;
> +	unsigned int last_clu = FREE_CLUSTER;
> +	struct exfat_chain clu;
> +	struct exfat_timestamp tm;
> +	struct exfat_dentry *ep, *ep2;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
> +	struct exfat_entry_set_cache *es = NULL;
> +	int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
> +
> +	/* check if the given file ID is opened */
> +	if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
> +		return -EPERM;
> +
> +	exfat_set_vol_flags(sb, VOL_DIRTY);
> +
> +	num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode),
> sbi);
> +	num_clusters_phys =
> +		EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->i_size_ondisk,
> sbi);
> +
> +	exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei-
> >flags);
> +
> +	if (new_size > 0) {
> +		/*
> +		 * Truncate FAT chain num_clusters after the first
> cluster
> +		 * num_clusters = min(new, phys);
> +		 */
> +		unsigned int num_clusters =
> +			min(num_clusters_new, num_clusters_phys);
> +
> +		/*
> +		 * Follow FAT chain
> +		 * (defensive coding - works fine even with corrupted
> FAT table
> +		 */
> +		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
> +			clu.dir += num_clusters;
> +			clu.size -= num_clusters;
> +		} else {
> +			while (num_clusters > 0) {
> +				last_clu = clu.dir;
> +				if (exfat_get_next_cluster(sb,
> &(clu.dir)))
> +					return -EIO;
> +
> +				num_clusters--;
> +				clu.size--;
> +			}
> +		}
> +	} else {
> +		ei->flags = ALLOC_NO_FAT_CHAIN;
> +		ei->start_clu = EOF_CLUSTER;
> +	}
> +
> +	i_size_write(inode, new_size);
> +
> +	if (ei->type == TYPE_FILE)
> +		ei->attr |= ATTR_ARCHIVE;
> +
> +	/* update the directory entry */
> +	if (!evict) {
> +		es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
> +				ES_ALL_ENTRIES, &ep);
> +		if (!es)
> +			return -EIO;
> +		ep2 = ep + 1;

The ep2 could point out on the garbage here. Maybe, it makes sense to
add some check here?

Thanks,
Viacheslav Dubeyko.

> +
> +		exfat_set_entry_time(ep, exfat_tm_now(EXFAT_SB(sb),
> &tm),
> +				TM_MODIFY);
> +		ep->file_attr = cpu_to_le16(ei->attr);
> +
> +		/* File size should be zero if there is no cluster
> allocated */
> +		if (ei->start_clu == EOF_CLUSTER)
> +			ep->stream_valid_size = ep->stream_size = 0;
> +		else {
> +			ep->stream_valid_size = cpu_to_le64(new_size);
> +			ep->stream_size = ep->stream_valid_size;
> +		}
> +
> +		if (new_size == 0) {
> +			/* Any directory can not be truncated to zero
> */
> +			WARN_ON(ei->type != TYPE_FILE);
> +
> +			ep2->stream_flags = ALLOC_FAT_CHAIN;
> +			ep2->stream_start_clu = FREE_CLUSTER;
> +		}
> +
> +		if (exfat_update_dir_chksum_with_entry_set(sb, es,
> +		    inode_needs_sync(inode)))
> +			return -EIO;
> +		kfree(es);
> +	}
> +
> +	/* cut off from the FAT chain */
> +	if (ei->flags == ALLOC_FAT_CHAIN && last_clu != FREE_CLUSTER &&
> +			last_clu != EOF_CLUSTER) {
> +		if (exfat_ent_set(sb, last_clu, EOF_CLUSTER))
> +			return -EIO;
> +	}
> +
> +	/* invalidate cache and free the clusters */
> +	/* clear exfat cache */
> +	exfat_cache_inval_inode(inode);
> +
> +	/* hint information */
> +	ei->hint_bmap.off = EOF_CLUSTER;
> +	ei->hint_bmap.clu = EOF_CLUSTER;
> +	if (ei->rwoffset > new_size)
> +		ei->rwoffset = new_size;
> +
> +	/* hint_stat will be used if this is directory. */
> +	ei->hint_stat.eidx = 0;
> +	ei->hint_stat.clu = ei->start_clu;
> +	ei->hint_femp.eidx = EXFAT_HINT_NONE;
> +
> +	/* free the clusters */
> +	if (exfat_free_cluster(inode, &clu))
> +		return -EIO;
> +
> +	exfat_set_vol_flags(sb, VOL_CLEAN);
> +
> +	return 0;
> +}
> +
> +void exfat_truncate(struct inode *inode, loff_t size)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	unsigned int blocksize = 1 << inode->i_blkbits;
> +	loff_t aligned_size;
> +	int err;
> +
> +	mutex_lock(&sbi->s_lock);
> +	if (EXFAT_I(inode)->start_clu == 0) {
> +		/*
> +		 * Empty start_clu != ~0 (not allocated)
> +		 */
> +		exfat_fs_error(sb, "tried to truncate zeroed
> cluster.");
> +		goto write_size;
> +	}
> +
> +	err = __exfat_truncate(inode, i_size_read(inode));
> +	if (err)
> +		goto write_size;
> +
> +	inode->i_ctime = inode->i_mtime = current_time(inode);
> +	if (IS_DIRSYNC(inode))
> +		exfat_sync_inode(inode);
> +	else
> +		mark_inode_dirty(inode);
> +
> +	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size -
> 1)) &
> +			~(sbi->cluster_size - 1)) >> inode->i_blkbits;
> +write_size:
> +	aligned_size = i_size_read(inode);
> +	if (aligned_size & (blocksize - 1)) {
> +		aligned_size |= (blocksize - 1);
> +		aligned_size++;
> +	}
> +
> +	if (EXFAT_I(inode)->i_size_ondisk > i_size_read(inode))
> +		EXFAT_I(inode)->i_size_ondisk = aligned_size;
> +
> +	if (EXFAT_I(inode)->i_size_aligned > i_size_read(inode))
> +		EXFAT_I(inode)->i_size_aligned = aligned_size;
> +	mutex_unlock(&sbi->s_lock);
> +}
> +
> +int exfat_getattr(const struct path *path, struct kstat *stat,
> +		unsigned int request_mask, unsigned int query_flags)
> +{
> +	struct inode *inode = d_backing_inode(path->dentry);
> +
> +	generic_fillattr(inode, stat);
> +	stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
> +	return 0;
> +}
> +
> +int exfat_setattr(struct dentry *dentry, struct iattr *attr)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
> +	struct inode *inode = dentry->d_inode;
> +	unsigned int ia_valid;
> +	int error;
> +
> +	if ((attr->ia_valid & ATTR_SIZE) &&
> +	    attr->ia_size > i_size_read(inode)) {
> +		error = exfat_cont_expand(inode, attr->ia_size);
> +		if (error || attr->ia_valid == ATTR_SIZE)
> +			return error;
> +		attr->ia_valid &= ~ATTR_SIZE;
> +	}
> +
> +	/* Check for setting the inode time. */
> +	ia_valid = attr->ia_valid;
> +	if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET |
> ATTR_TIMES_SET)) &&
> +	    exfat_allow_set_time(sbi, inode)) {
> +		attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
> +				ATTR_TIMES_SET);
> +	}
> +
> +	error = setattr_prepare(dentry, attr);
> +	attr->ia_valid = ia_valid;
> +	if (error)
> +		return error;
> +
> +	if (((attr->ia_valid & ATTR_UID) &&
> +	     !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
> +	    ((attr->ia_valid & ATTR_GID) &&
> +	     !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
> +	    ((attr->ia_valid & ATTR_MODE) &&
> +	     (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777))))
> +		return -EPERM;
> +
> +	/*
> +	 * We don't return -EPERM here. Yes, strange, but this is too
> +	 * old behavior.
> +	 */
> +	if (attr->ia_valid & ATTR_MODE) {
> +		if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) <
> 0)
> +			attr->ia_valid &= ~ATTR_MODE;
> +	}
> +
> +	if (attr->ia_valid & ATTR_SIZE) {
> +		down_write(&EXFAT_I(inode)->truncate_lock);
> +		truncate_setsize(inode, attr->ia_size);
> +		exfat_truncate(inode, attr->ia_size);
> +		up_write(&EXFAT_I(inode)->truncate_lock);
> +	}
> +
> +	setattr_copy(inode, attr);
> +	mark_inode_dirty(inode);
> +
> +	return error;
> +}
> +
> +const struct file_operations exfat_file_operations = {
> +	.llseek      = generic_file_llseek,
> +	.read_iter   = generic_file_read_iter,
> +	.write_iter  = generic_file_write_iter,
> +	.mmap        = generic_file_mmap,
> +	.fsync       = generic_file_fsync,
> +	.splice_read = generic_file_splice_read,
> +};
> +
> +const struct inode_operations exfat_file_inode_operations = {
> +	.setattr     = exfat_setattr,
> +	.getattr     = exfat_getattr,
> +};

RE: [PATCH v6 05/13] exfat: add file operations

[Namjae Jeon]

> > +	/* Of the r and x bits, all (subject to umask) must be
> > present.*/
> > +	if ((perm & 0555) != (i_mode & 0555))
I modified it due to warnning alarm from checkpatch.pl.
Other octal permissions are same reason.
WARNING: Symbolic permissions 'S_IRUGO | S_IXUGO' are not preferred. Consider using octal permissions '0555'.
+       if ((perm & (S_IRUGO | S_IXUGO)) != (i_mode & (S_IRUGO | S_IXUGO)))

> > +	/* update the directory entry */
> > +	if (!evict) {
> > +		es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
> > +				ES_ALL_ENTRIES, &ep);
> > +		if (!es)
> > +			return -EIO;
> > +		ep2 = ep + 1;
> 
> The ep2 could point out on the garbage here. Maybe, it makes sense to
> add some check here?
Could you please elaborate more? How could ep2 be the garbage?
I want you to check exfat_get_dentry_set().

Thanks for your review!

[PATCH v6 06/13] exfat: add exfat entry operations

[Namjae Jeon]

This adds the implementation of exfat entry operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/fatent.c | 472 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 472 insertions(+)
 create mode 100644 fs/exfat/fatent.c

diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
new file mode 100644
index 000000000000..0598aa2d04c1
--- /dev/null
+++ b/fs/exfat/fatent.c
@@ -0,0 +1,472 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static int __exfat_ent_get(struct super_block *sb, unsigned int loc,
+		unsigned int *content)
+{
+	unsigned int off, _content;
+	sector_t sec;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+
+	sec = sbi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2));
+	off = (loc << 2) & (sb->s_blocksize - 1);
+
+	bh = sb_bread(sb, sec);
+	if (!bh)
+		return -EIO;
+
+	_content = le32_to_cpu(*(__le32 *)(&bh->b_data[off]));
+
+	/* remap reserved clusters to simplify code */
+	if (_content >= CLUSTER_32(0xFFFFFFF8))
+		_content = EOF_CLUSTER;
+
+	*content = CLUSTER_32(_content);
+	brelse(bh);
+	return 0;
+}
+
+int exfat_ent_set(struct super_block *sb, unsigned int loc,
+		unsigned int content)
+{
+	unsigned int off;
+	sector_t sec;
+	__le32 *fat_entry;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+
+	sec = sbi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2));
+	off = (loc << 2) & (sb->s_blocksize - 1);
+
+	bh = sb_bread(sb, sec);
+	if (!bh)
+		return -EIO;
+
+	fat_entry = (__le32 *)&(bh->b_data[off]);
+	*fat_entry = cpu_to_le32(content);
+	exfat_update_bh(sb, bh, sb->s_flags & SB_SYNCHRONOUS);
+	exfat_mirror_bh(sb, sec, bh);
+	brelse(bh);
+	return 0;
+}
+
+static inline bool is_reserved_cluster(unsigned int clus)
+{
+	if (clus == FREE_CLUSTER || clus == EOF_CLUSTER || clus == BAD_CLUSTER)
+		return true;
+	return false;
+}
+
+static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
+		unsigned int clus)
+{
+	if (clus < BASE_CLUSTER || sbi->num_clusters <= clus)
+		return false;
+	return true;
+}
+
+int exfat_ent_get(struct super_block *sb, unsigned int loc,
+		unsigned int *content)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int err;
+
+	if (!is_valid_cluster(sbi, loc)) {
+		exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)",
+			loc);
+		return -EIO;
+	}
+
+	err = __exfat_ent_get(sb, loc, content);
+	if (err) {
+		exfat_fs_error(sb,
+			"failed to access to FAT (entry 0x%08x, err:%d)",
+			loc, err);
+		return err;
+	}
+
+	if (!is_reserved_cluster(*content) &&
+			!is_valid_cluster(sbi, *content)) {
+		exfat_fs_error(sb,
+			"invalid access to FAT (entry 0x%08x) bogus content (0x%08x)",
+			loc, *content);
+		return -EIO;
+	}
+
+	if (*content == FREE_CLUSTER) {
+		exfat_fs_error(sb,
+			"invalid access to FAT free cluster (entry 0x%08x)",
+			loc);
+		return -EIO;
+	}
+
+	if (*content == BAD_CLUSTER) {
+		exfat_fs_error(sb,
+			"invalid access to FAT bad cluster (entry 0x%08x)",
+			loc);
+		return -EIO;
+	}
+	return 0;
+}
+
+int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
+		unsigned int len)
+{
+	if (!len)
+		return 0;
+
+	while (len > 1) {
+		if (exfat_ent_set(sb, chain, chain + 1))
+			return -EIO;
+		chain++;
+		len--;
+	}
+
+	if (exfat_ent_set(sb, chain, EOF_CLUSTER))
+		return -EIO;
+	return 0;
+}
+
+int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
+{
+	unsigned int num_clusters = 0;
+	unsigned int clu;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	/* invalid cluster number */
+	if (p_chain->dir == FREE_CLUSTER || p_chain->dir == EOF_CLUSTER)
+		return 0;
+
+	/* no cluster to truncate */
+	if (p_chain->size == 0)
+		return 0;
+
+	/* check cluster validation */
+	if (p_chain->dir < 2 && p_chain->dir >= sbi->num_clusters) {
+		exfat_msg(sb, KERN_ERR, "invalid start cluster (%u)",
+				p_chain->dir);
+		return -EIO;
+	}
+
+	set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
+	clu = p_chain->dir;
+
+	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
+		do {
+			exfat_clear_bitmap(inode, clu-2);
+			clu++;
+
+			num_clusters++;
+		} while (num_clusters < p_chain->size);
+	} else {
+		do {
+			exfat_clear_bitmap(inode, (clu - BASE_CLUSTER));
+
+			if (exfat_get_next_cluster(sb, &clu))
+				goto dec_used_clus;
+
+			num_clusters++;
+		} while (clu != EOF_CLUSTER);
+	}
+
+dec_used_clus:
+	sbi->used_clusters -= num_clusters;
+	return 0;
+}
+
+int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
+		unsigned int *ret_clu)
+{
+	unsigned int clu, next;
+	unsigned int count = 0;
+
+	next = p_chain->dir;
+	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
+		*ret_clu = next + p_chain->size - 1;
+		return 0;
+	}
+
+	do {
+		count++;
+		clu = next;
+		if (exfat_ent_get(sb, clu, &next))
+			return -EIO;
+	} while (next != EOF_CLUSTER);
+
+	if (p_chain->size != count) {
+		exfat_fs_error(sb,
+			"bogus directory size (clus : ondisk(%d) != counted(%d))",
+			p_chain->size, count);
+		return -EIO;
+	}
+
+	*ret_clu = clu;
+	return 0;
+}
+
+static inline int exfat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
+{
+	int i, err = 0;
+
+	for (i = 0; i < nr_bhs; i++)
+		write_dirty_buffer(bhs[i], 0);
+
+	for (i = 0; i < nr_bhs; i++) {
+		wait_on_buffer(bhs[i]);
+		if (!err && !buffer_uptodate(bhs[i]))
+			err = -EIO;
+	}
+	return err;
+}
+
+int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
+{
+	struct super_block *sb = dir->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+	int nr_bhs = MAX_BUF_PER_PAGE;
+	sector_t blknr, last_blknr;
+	int err, i, n;
+
+	blknr = exfat_cluster_to_sector(sbi, clu);
+	last_blknr = blknr + sbi->sect_per_clus;
+
+	if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
+		exfat_fs_error_ratelimit(sb,
+			"%s: out of range(sect:%llu len:%u)",
+			__func__, (unsigned long long)blknr,
+			sbi->sect_per_clus);
+		return -EIO;
+	}
+
+	/* Zeroing the unused blocks on this cluster */
+	n = 0;
+	while (blknr < last_blknr) {
+		bhs[n] = sb_getblk(sb, blknr);
+		if (!bhs[n]) {
+			err = -ENOMEM;
+			goto release_bhs;
+		}
+		memset(bhs[n]->b_data, 0, sb->s_blocksize);
+		exfat_update_bh(sb, bhs[n], 0);
+
+		n++;
+		blknr++;
+
+		if (n == nr_bhs) {
+			if (IS_DIRSYNC(dir)) {
+				err = exfat_sync_bhs(bhs, n);
+				if (err)
+					goto release_bhs;
+			}
+
+			for (i = 0; i < n; i++)
+				brelse(bhs[i]);
+			n = 0;
+		}
+	}
+
+	if (IS_DIRSYNC(dir)) {
+		err = exfat_sync_bhs(bhs, n);
+		if (err)
+			goto release_bhs;
+	}
+
+	for (i = 0; i < n; i++)
+		brelse(bhs[i]);
+
+	return 0;
+
+release_bhs:
+	exfat_msg(sb, KERN_ERR, "failed zeroed sect %llu\n",
+		(unsigned long long)blknr);
+	for (i = 0; i < n; i++)
+		bforget(bhs[i]);
+	return err;
+}
+
+int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
+		struct exfat_chain *p_chain)
+{
+	int ret = -ENOSPC;
+	unsigned int num_clusters = 0, total_cnt;
+	unsigned int hint_clu, new_clu, last_clu = EOF_CLUSTER;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	total_cnt = sbi->num_clusters - BASE_CLUSTER;
+
+	if (unlikely(total_cnt < sbi->used_clusters)) {
+		exfat_fs_error_ratelimit(sb,
+			"%s: invalid used clusters(t:%u,u:%u)\n",
+			__func__, total_cnt, sbi->used_clusters);
+		return -EIO;
+	}
+
+	if (num_alloc > total_cnt - sbi->used_clusters)
+		return -ENOSPC;
+
+	hint_clu = p_chain->dir;
+	/* find new cluster */
+	if (hint_clu == EOF_CLUSTER) {
+		if (sbi->clu_srch_ptr < BASE_CLUSTER) {
+			exfat_msg(sb, KERN_ERR,
+				"sbi->clu_srch_ptr is invalid (%u)\n",
+				sbi->clu_srch_ptr);
+			sbi->clu_srch_ptr = BASE_CLUSTER;
+		}
+
+		hint_clu = exfat_test_bitmap(sb,
+				sbi->clu_srch_ptr - BASE_CLUSTER);
+		if (hint_clu == EOF_CLUSTER)
+			return -ENOSPC;
+	}
+
+	/* check cluster validation */
+	if (hint_clu < BASE_CLUSTER && hint_clu >= sbi->num_clusters) {
+		exfat_msg(sb, KERN_ERR, "hint_cluster is invalid (%u)\n",
+			hint_clu);
+		hint_clu = BASE_CLUSTER;
+		if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
+			if (exfat_chain_cont_cluster(sb, p_chain->dir,
+					num_clusters))
+				return -EIO;
+			p_chain->flags = ALLOC_FAT_CHAIN;
+		}
+	}
+
+	set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
+
+	p_chain->dir = EOF_CLUSTER;
+
+	while ((new_clu = exfat_test_bitmap(sb,
+			hint_clu - BASE_CLUSTER)) != EOF_CLUSTER) {
+		if (new_clu != hint_clu &&
+		    p_chain->flags == ALLOC_NO_FAT_CHAIN) {
+			if (exfat_chain_cont_cluster(sb, p_chain->dir,
+					num_clusters)) {
+				ret = -EIO;
+				goto free_cluster;
+			}
+			p_chain->flags = ALLOC_FAT_CHAIN;
+		}
+
+		/* update allocation bitmap */
+		if (exfat_set_bitmap(inode, new_clu - BASE_CLUSTER)) {
+			ret = -EIO;
+			goto free_cluster;
+		}
+
+		num_clusters++;
+
+		/* update FAT table */
+		if (p_chain->flags == ALLOC_FAT_CHAIN) {
+			if (exfat_ent_set(sb, new_clu, EOF_CLUSTER)) {
+				ret = -EIO;
+				goto free_cluster;
+			}
+		}
+
+		if (p_chain->dir == EOF_CLUSTER) {
+			p_chain->dir = new_clu;
+		} else if (p_chain->flags == ALLOC_FAT_CHAIN) {
+			if (exfat_ent_set(sb, last_clu, new_clu)) {
+				ret = -EIO;
+				goto free_cluster;
+			}
+		}
+		last_clu = new_clu;
+
+		if (--num_alloc == 0) {
+			sbi->clu_srch_ptr = hint_clu;
+			sbi->used_clusters += num_clusters;
+
+			p_chain->size += num_clusters;
+			return 0;
+		}
+
+		hint_clu = new_clu + 1;
+		if (hint_clu >= sbi->num_clusters) {
+			hint_clu = BASE_CLUSTER;
+
+			if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
+				if (exfat_chain_cont_cluster(sb, p_chain->dir,
+						num_clusters)) {
+					ret = -EIO;
+					goto free_cluster;
+				}
+				p_chain->flags = ALLOC_FAT_CHAIN;
+			}
+		}
+	}
+free_cluster:
+	if (num_clusters)
+		exfat_free_cluster(inode, p_chain);
+	return ret;
+}
+
+int exfat_count_num_clusters(struct super_block *sb,
+		struct exfat_chain *p_chain, unsigned int *ret_count)
+{
+	unsigned int i, count;
+	unsigned int clu;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!p_chain->dir || p_chain->dir == EOF_CLUSTER) {
+		*ret_count = 0;
+		return 0;
+	}
+
+	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
+		*ret_count = p_chain->size;
+		return 0;
+	}
+
+	clu = p_chain->dir;
+	count = 0;
+	for (i = BASE_CLUSTER; i < sbi->num_clusters; i++) {
+		count++;
+		if (exfat_ent_get(sb, clu, &clu))
+			return -EIO;
+		if (clu == EOF_CLUSTER)
+			break;
+	}
+
+	*ret_count = count;
+	return 0;
+}
+
+int exfat_mirror_bh(struct super_block *sb, sector_t sec,
+		struct buffer_head *bh)
+{
+	struct buffer_head *c_bh;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	sector_t sec2;
+	int err = 0;
+
+	if (sbi->FAT2_start_sector != sbi->FAT1_start_sector) {
+		sec2 = sec - sbi->FAT1_start_sector + sbi->FAT2_start_sector;
+		c_bh = sb_getblk(sb, sec2);
+		if (!c_bh)
+			return -ENOMEM;
+		memcpy(c_bh->b_data, bh->b_data, sb->s_blocksize);
+		set_buffer_uptodate(c_bh);
+		mark_buffer_dirty(c_bh);
+		if (sb->s_flags & SB_SYNCHRONOUS)
+			err = sync_dirty_buffer(c_bh);
+		brelse(c_bh);
+	}
+
+	return err;
+}
-- 
2.17.1

Re: [PATCH v6 06/13] exfat: add exfat entry operations

[Vyacheslav Dubeyko]

On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of exfat entry operations for exfat.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
>  fs/exfat/fatent.c | 472
> ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 472 insertions(+)
>  create mode 100644 fs/exfat/fatent.c
> 
> diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
> new file mode 100644
> index 000000000000..0598aa2d04c1
> --- /dev/null
> +++ b/fs/exfat/fatent.c
> @@ -0,0 +1,472 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/slab.h>
> +#include <asm/unaligned.h>
> +#include <linux/buffer_head.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +static int __exfat_ent_get(struct super_block *sb, unsigned int loc,
> +		unsigned int *content)
> +{
> +	unsigned int off, _content;
> +	sector_t sec;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +
> +	sec = sbi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-
> 2));
> +	off = (loc << 2) & (sb->s_blocksize - 1);

It's slightly hard to follow why 2 is used here. Maybe, it makes sense
to rework the code here? I believe the constant could make this code
more easy to understand.

> +
> +	bh = sb_bread(sb, sec);
> +	if (!bh)
> +		return -EIO;
> +
> +	_content = le32_to_cpu(*(__le32 *)(&bh->b_data[off]));
> +
> +	/* remap reserved clusters to simplify code */
> +	if (_content >= CLUSTER_32(0xFFFFFFF8))
> +		_content = EOF_CLUSTER;
> +
> +	*content = CLUSTER_32(_content);
> +	brelse(bh);
> +	return 0;
> +}
> +
> +int exfat_ent_set(struct super_block *sb, unsigned int loc,
> +		unsigned int content)
> +{
> +	unsigned int off;
> +	sector_t sec;
> +	__le32 *fat_entry;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bh;
> +
> +	sec = sbi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-
> 2));
> +	off = (loc << 2) & (sb->s_blocksize - 1);

Ditto.

> +
> +	bh = sb_bread(sb, sec);
> +	if (!bh)
> +		return -EIO;
> +
> +	fat_entry = (__le32 *)&(bh->b_data[off]);
> +	*fat_entry = cpu_to_le32(content);
> +	exfat_update_bh(sb, bh, sb->s_flags & SB_SYNCHRONOUS);
> +	exfat_mirror_bh(sb, sec, bh);
> +	brelse(bh);
> +	return 0;
> +}
> +
> +static inline bool is_reserved_cluster(unsigned int clus)
> +{
> +	if (clus == FREE_CLUSTER || clus == EOF_CLUSTER || clus ==
> BAD_CLUSTER)
> +		return true;
> +	return false;
> +}
> +
> +static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
> +		unsigned int clus)
> +{
> +	if (clus < BASE_CLUSTER || sbi->num_clusters <= clus)
> +		return false;
> +	return true;
> +}
> +
> +int exfat_ent_get(struct super_block *sb, unsigned int loc,
> +		unsigned int *content)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	int err;
> +
> +	if (!is_valid_cluster(sbi, loc)) {
> +		exfat_fs_error(sb, "invalid access to FAT (entry
> 0x%08x)",
> +			loc);
> +		return -EIO;
> +	}
> +
> +	err = __exfat_ent_get(sb, loc, content);
> +	if (err) {
> +		exfat_fs_error(sb,
> +			"failed to access to FAT (entry 0x%08x,
> err:%d)",
> +			loc, err);
> +		return err;
> +	}
> +
> +	if (!is_reserved_cluster(*content) &&
> +			!is_valid_cluster(sbi, *content)) {
> +		exfat_fs_error(sb,
> +			"invalid access to FAT (entry 0x%08x) bogus
> content (0x%08x)",
> +			loc, *content);
> +		return -EIO;
> +	}
> +
> +	if (*content == FREE_CLUSTER) {
> +		exfat_fs_error(sb,
> +			"invalid access to FAT free cluster (entry
> 0x%08x)",
> +			loc);
> +		return -EIO;
> +	}
> +
> +	if (*content == BAD_CLUSTER) {
> +		exfat_fs_error(sb,
> +			"invalid access to FAT bad cluster (entry
> 0x%08x)",
> +			loc);
> +		return -EIO;
> +	}
> +	return 0;
> +}
> +
> +int exfat_chain_cont_cluster(struct super_block *sb, unsigned int
> chain,
> +		unsigned int len)
> +{
> +	if (!len)
> +		return 0;
> +
> +	while (len > 1) {
> +		if (exfat_ent_set(sb, chain, chain + 1))
> +			return -EIO;
> +		chain++;
> +		len--;
> +	}
> +
> +	if (exfat_ent_set(sb, chain, EOF_CLUSTER))
> +		return -EIO;
> +	return 0;
> +}
> +
> +int exfat_free_cluster(struct inode *inode, struct exfat_chain
> *p_chain)
> +{
> +	unsigned int num_clusters = 0;
> +	unsigned int clu;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	/* invalid cluster number */
> +	if (p_chain->dir == FREE_CLUSTER || p_chain->dir ==
> EOF_CLUSTER)
> +		return 0;
> +
> +	/* no cluster to truncate */
> +	if (p_chain->size == 0)
> +		return 0;
> +
> +	/* check cluster validation */
> +	if (p_chain->dir < 2 && p_chain->dir >= sbi->num_clusters) {
> +		exfat_msg(sb, KERN_ERR, "invalid start cluster (%u)",
> +				p_chain->dir);
> +		return -EIO;
> +	}
> +
> +	set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
> +	clu = p_chain->dir;
> +
> +	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
> +		do {
> +			exfat_clear_bitmap(inode, clu-2);

What if clu could be lesser than 2? Any gurantee of this?

> +			clu++;
> +
> +			num_clusters++;
> +		} while (num_clusters < p_chain->size);
> +	} else {
> +		do {
> +			exfat_clear_bitmap(inode, (clu -
> BASE_CLUSTER));

Ditto.

> +
> +			if (exfat_get_next_cluster(sb, &clu))
> +				goto dec_used_clus;
> +
> +			num_clusters++;
> +		} while (clu != EOF_CLUSTER);
> +	}
> +
> +dec_used_clus:
> +	sbi->used_clusters -= num_clusters;
> +	return 0;
> +}
> +
> +int exfat_find_last_cluster(struct super_block *sb, struct
> exfat_chain *p_chain,
> +		unsigned int *ret_clu)
> +{
> +	unsigned int clu, next;
> +	unsigned int count = 0;
> +
> +	next = p_chain->dir;
> +	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
> +		*ret_clu = next + p_chain->size - 1;
> +		return 0;
> +	}
> +
> +	do {
> +		count++;
> +		clu = next;
> +		if (exfat_ent_get(sb, clu, &next))
> +			return -EIO;
> +	} while (next != EOF_CLUSTER);
> +
> +	if (p_chain->size != count) {
> +		exfat_fs_error(sb,
> +			"bogus directory size (clus : ondisk(%d) !=
> counted(%d))",
> +			p_chain->size, count);
> +		return -EIO;
> +	}
> +
> +	*ret_clu = clu;
> +	return 0;
> +}
> +
> +static inline int exfat_sync_bhs(struct buffer_head **bhs, int
> nr_bhs)
> +{
> +	int i, err = 0;
> +
> +	for (i = 0; i < nr_bhs; i++)
> +		write_dirty_buffer(bhs[i], 0);
> +
> +	for (i = 0; i < nr_bhs; i++) {
> +		wait_on_buffer(bhs[i]);
> +		if (!err && !buffer_uptodate(bhs[i]))
> +			err = -EIO;
> +	}
> +	return err;
> +}
> +
> +int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
> +{
> +	struct super_block *sb = dir->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
> +	int nr_bhs = MAX_BUF_PER_PAGE;
> +	sector_t blknr, last_blknr;
> +	int err, i, n;
> +
> +	blknr = exfat_cluster_to_sector(sbi, clu);
> +	last_blknr = blknr + sbi->sect_per_clus;
> +
> +	if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
> +		exfat_fs_error_ratelimit(sb,
> +			"%s: out of range(sect:%llu len:%u)",
> +			__func__, (unsigned long long)blknr,
> +			sbi->sect_per_clus);
> +		return -EIO;
> +	}
> +
> +	/* Zeroing the unused blocks on this cluster */
> +	n = 0;
> +	while (blknr < last_blknr) {
> +		bhs[n] = sb_getblk(sb, blknr);
> +		if (!bhs[n]) {
> +			err = -ENOMEM;
> +			goto release_bhs;
> +		}
> +		memset(bhs[n]->b_data, 0, sb->s_blocksize);
> +		exfat_update_bh(sb, bhs[n], 0);
> +
> +		n++;
> +		blknr++;
> +
> +		if (n == nr_bhs) {
> +			if (IS_DIRSYNC(dir)) {
> +				err = exfat_sync_bhs(bhs, n);
> +				if (err)
> +					goto release_bhs;
> +			}
> +
> +			for (i = 0; i < n; i++)
> +				brelse(bhs[i]);
> +			n = 0;
> +		}
> +	}
> +
> +	if (IS_DIRSYNC(dir)) {
> +		err = exfat_sync_bhs(bhs, n);
> +		if (err)
> +			goto release_bhs;
> +	}
> +
> +	for (i = 0; i < n; i++)
> +		brelse(bhs[i]);
> +
> +	return 0;
> +
> +release_bhs:
> +	exfat_msg(sb, KERN_ERR, "failed zeroed sect %llu\n",
> +		(unsigned long long)blknr);
> +	for (i = 0; i < n; i++)
> +		bforget(bhs[i]);
> +	return err;
> +}
> +
> +int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
> +		struct exfat_chain *p_chain)
> +{
> +	int ret = -ENOSPC;
> +	unsigned int num_clusters = 0, total_cnt;
> +	unsigned int hint_clu, new_clu, last_clu = EOF_CLUSTER;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	total_cnt = sbi->num_clusters - BASE_CLUSTER;
> +
> +	if (unlikely(total_cnt < sbi->used_clusters)) {
> +		exfat_fs_error_ratelimit(sb,
> +			"%s: invalid used clusters(t:%u,u:%u)\n",
> +			__func__, total_cnt, sbi->used_clusters);
> +		return -EIO;
> +	}
> +
> +	if (num_alloc > total_cnt - sbi->used_clusters)
> +		return -ENOSPC;
> +
> +	hint_clu = p_chain->dir;
> +	/* find new cluster */
> +	if (hint_clu == EOF_CLUSTER) {
> +		if (sbi->clu_srch_ptr < BASE_CLUSTER) {
> +			exfat_msg(sb, KERN_ERR,
> +				"sbi->clu_srch_ptr is invalid (%u)\n",
> +				sbi->clu_srch_ptr);
> +			sbi->clu_srch_ptr = BASE_CLUSTER;
> +		}
> +
> +		hint_clu = exfat_test_bitmap(sb,
> +				sbi->clu_srch_ptr - BASE_CLUSTER);
> +		if (hint_clu == EOF_CLUSTER)
> +			return -ENOSPC;
> +	}
> +
> +	/* check cluster validation */
> +	if (hint_clu < BASE_CLUSTER && hint_clu >= sbi->num_clusters) {
> +		exfat_msg(sb, KERN_ERR, "hint_cluster is invalid
> (%u)\n",
> +			hint_clu);
> +		hint_clu = BASE_CLUSTER;
> +		if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
> +			if (exfat_chain_cont_cluster(sb, p_chain->dir,
> +					num_clusters))
> +				return -EIO;
> +			p_chain->flags = ALLOC_FAT_CHAIN;
> +		}
> +	}
> +
> +	set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
> +
> +	p_chain->dir = EOF_CLUSTER;
> +
> +	while ((new_clu = exfat_test_bitmap(sb,
> +			hint_clu - BASE_CLUSTER)) != EOF_CLUSTER) {
> +		if (new_clu != hint_clu &&
> +		    p_chain->flags == ALLOC_NO_FAT_CHAIN) {
> +			if (exfat_chain_cont_cluster(sb, p_chain->dir,
> +					num_clusters)) {
> +				ret = -EIO;
> +				goto free_cluster;
> +			}
> +			p_chain->flags = ALLOC_FAT_CHAIN;
> +		}
> +
> +		/* update allocation bitmap */
> +		if (exfat_set_bitmap(inode, new_clu - BASE_CLUSTER)) {
> +			ret = -EIO;
> +			goto free_cluster;
> +		}
> +
> +		num_clusters++;
> +
> +		/* update FAT table */
> +		if (p_chain->flags == ALLOC_FAT_CHAIN) {
> +			if (exfat_ent_set(sb, new_clu, EOF_CLUSTER)) {
> +				ret = -EIO;
> +				goto free_cluster;
> +			}
> +		}
> +
> +		if (p_chain->dir == EOF_CLUSTER) {
> +			p_chain->dir = new_clu;
> +		} else if (p_chain->flags == ALLOC_FAT_CHAIN) {
> +			if (exfat_ent_set(sb, last_clu, new_clu)) {
> +				ret = -EIO;
> +				goto free_cluster;
> +			}
> +		}
> +		last_clu = new_clu;
> +
> +		if (--num_alloc == 0) {
> +			sbi->clu_srch_ptr = hint_clu;
> +			sbi->used_clusters += num_clusters;
> +
> +			p_chain->size += num_clusters;
> +			return 0;
> +		}
> +
> +		hint_clu = new_clu + 1;
> +		if (hint_clu >= sbi->num_clusters) {
> +			hint_clu = BASE_CLUSTER;
> +
> +			if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
> +				if (exfat_chain_cont_cluster(sb,
> p_chain->dir,
> +						num_clusters)) {
> +					ret = -EIO;
> +					goto free_cluster;
> +				}
> +				p_chain->flags = ALLOC_FAT_CHAIN;
> +			}
> +		}
> +	}
> +free_cluster:
> +	if (num_clusters)
> +		exfat_free_cluster(inode, p_chain);
> +	return ret;
> +}
> +
> +int exfat_count_num_clusters(struct super_block *sb,
> +		struct exfat_chain *p_chain, unsigned int *ret_count)
> +{
> +	unsigned int i, count;
> +	unsigned int clu;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	if (!p_chain->dir || p_chain->dir == EOF_CLUSTER) {
> +		*ret_count = 0;
> +		return 0;
> +	}
> +
> +	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
> +		*ret_count = p_chain->size;
> +		return 0;
> +	}
> +
> +	clu = p_chain->dir;
> +	count = 0;
> +	for (i = BASE_CLUSTER; i < sbi->num_clusters; i++) {

Why does it start from BASE_CLUSTER? Maybe it makese sense to comment
this?

Thanks,
Viacheslav Dubeyko.

> +		count++;
> +		if (exfat_ent_get(sb, clu, &clu))
> +			return -EIO;
> +		if (clu == EOF_CLUSTER)
> +			break;
> +	}
> +
> +	*ret_count = count;
> +	return 0;
> +}
> +
> +int exfat_mirror_bh(struct super_block *sb, sector_t sec,
> +		struct buffer_head *bh)
> +{
> +	struct buffer_head *c_bh;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	sector_t sec2;
> +	int err = 0;
> +
> +	if (sbi->FAT2_start_sector != sbi->FAT1_start_sector) {
> +		sec2 = sec - sbi->FAT1_start_sector + sbi-
> >FAT2_start_sector;
> +		c_bh = sb_getblk(sb, sec2);
> +		if (!c_bh)
> +			return -ENOMEM;
> +		memcpy(c_bh->b_data, bh->b_data, sb->s_blocksize);
> +		set_buffer_uptodate(c_bh);
> +		mark_buffer_dirty(c_bh);
> +		if (sb->s_flags & SB_SYNCHRONOUS)
> +			err = sync_dirty_buffer(c_bh);
> +		brelse(c_bh);
> +	}
> +
> +	return err;
> +}

[PATCH v6 07/13] exfat: add bitmap operations

[Namjae Jeon]

This adds the implementation of bitmap operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/balloc.c | 272 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 272 insertions(+)
 create mode 100644 fs/exfat/balloc.c

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
new file mode 100644
index 000000000000..d7b70620e349
--- /dev/null
+++ b/fs/exfat/balloc.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static const unsigned char free_bit[] = {
+	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*  0 ~  19*/
+	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~  39*/
+	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~  59*/
+	0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~  79*/
+	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~  99*/
+	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/
+	0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/
+	0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/
+	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/
+	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/
+	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/
+	0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/
+	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0                /*240 ~ 254*/
+};
+
+static const unsigned char used_bit[] = {
+	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/*  0 ~  19*/
+	2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~  39*/
+	2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~  59*/
+	4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~  79*/
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~  99*/
+	3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/
+	4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/
+	3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/
+	4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/
+	3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/
+	5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/
+	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8             /*240 ~ 255*/
+};
+
+/*
+ *  Allocation Bitmap Management Functions
+ */
+static int exfat_allocate_bitmap(struct super_block *sb,
+		struct exfat_dentry *ep)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	long long map_size;
+	unsigned int i, need_map_size;
+	sector_t sector;
+
+	sbi->map_clu = le32_to_cpu(ep->bitmap_start_clu);
+	map_size = le64_to_cpu(ep->bitmap_size);
+	need_map_size = (((sbi->num_clusters - BASE_CLUSTER) - 1) >> 3) + 1;
+	if (need_map_size != map_size) {
+		exfat_msg(sb, KERN_ERR,
+				"bogus allocation bitmap size(need : %u, cur : %lld)",
+				need_map_size, map_size);
+		/*
+		 * Only allowed when bogus allocation
+		 * bitmap size is large
+		 */
+		if (need_map_size > map_size)
+			return -EIO;
+	}
+	sbi->map_sectors = ((need_map_size - 1) >>
+			(sb->s_blocksize_bits)) + 1;
+	sbi->vol_amap = kmalloc_array(sbi->map_sectors,
+				sizeof(struct buffer_head *), GFP_KERNEL);
+	if (!sbi->vol_amap)
+		return -ENOMEM;
+
+	sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
+	for (i = 0; i < sbi->map_sectors; i++) {
+		sbi->vol_amap[i] = sb_bread(sb, sector + i);
+		if (!sbi->vol_amap[i]) {
+			/* release all buffers and free vol_amap */
+			int j = 0;
+
+			while (j < i)
+				brelse(sbi->vol_amap[j++]);
+
+			kfree(sbi->vol_amap);
+			sbi->vol_amap = NULL;
+			return -EIO;
+		}
+	}
+
+	sbi->pbr_bh = NULL;
+	return 0;
+}
+
+int exfat_load_bitmap(struct super_block *sb)
+{
+	unsigned int i, type;
+	struct exfat_chain clu;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+
+	while (clu.dir != EOF_CLUSTER) {
+		for (i = 0; i < sbi->dentries_per_clu; i++) {
+			struct exfat_dentry *ep;
+			struct buffer_head *bh;
+
+			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
+			if (!ep)
+				return -EIO;
+
+			type = exfat_get_entry_type(ep);
+			if (type == TYPE_UNUSED)
+				break;
+			if (type != TYPE_BITMAP)
+				continue;
+			if (ep->bitmap_flags == 0x0) {
+				int err;
+
+				err = exfat_allocate_bitmap(sb, ep);
+				brelse(bh);
+				return err;
+			}
+			brelse(bh);
+		}
+
+		if (exfat_get_next_cluster(sb, &clu.dir))
+			return -EIO;
+	}
+
+	return -EINVAL;
+}
+
+void exfat_free_bitmap(struct super_block *sb)
+{
+	int i;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	brelse(sbi->pbr_bh);
+
+	for (i = 0; i < sbi->map_sectors; i++)
+		__brelse(sbi->vol_amap[i]);
+
+	kfree(sbi->vol_amap);
+	sbi->vol_amap = NULL;
+}
+
+/*
+ * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
+ * the cluster heap.
+ */
+int exfat_set_bitmap(struct inode *inode, unsigned int clu)
+{
+	int i, b;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	i = clu >> (sb->s_blocksize_bits + 3);
+	b = clu & ((sb->s_blocksize << 3) - 1);
+
+	set_bit_le(b, sbi->vol_amap[i]->b_data);
+	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));
+	return 0;
+}
+
+/*
+ * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
+ * the cluster heap.
+ */
+void exfat_clear_bitmap(struct inode *inode, unsigned int clu)
+{
+	int i, b;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_mount_options *opts = &sbi->options;
+
+	i = clu >> (sb->s_blocksize_bits + 3);
+	b = clu & ((sb->s_blocksize << 3) - 1);
+
+	clear_bit_le(b, sbi->vol_amap[i]->b_data);
+	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));
+
+	if (opts->discard) {
+		int ret_discard;
+
+		ret_discard = sb_issue_discard(sb,
+				exfat_cluster_to_sector(sbi, clu + 2),
+				(1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
+
+		if (ret_discard == -EOPNOTSUPP) {
+			exfat_msg(sb, KERN_ERR,
+				"discard not supported by device, disabling");
+			opts->discard = 0;
+		}
+	}
+}
+
+/*
+ * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
+ * the cluster heap.
+ */
+unsigned int exfat_test_bitmap(struct super_block *sb, unsigned int clu)
+{
+	unsigned int i, map_i, map_b;
+	unsigned int clu_base, clu_free;
+	unsigned char k, clu_mask;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	clu_base = (clu & ~(0x7)) + 2;
+	clu_mask = (1 << (clu - clu_base + 2)) - 1;
+
+	map_i = clu >> (sb->s_blocksize_bits + 3);
+	map_b = (clu >> 3) & (unsigned int)(sb->s_blocksize - 1);
+
+	for (i = 2; i < sbi->num_clusters; i += 8) {
+		k = *(sbi->vol_amap[map_i]->b_data + map_b);
+		if (clu_mask > 0) {
+			k |= clu_mask;
+			clu_mask = 0;
+		}
+		if (k < 0xFF) {
+			clu_free = clu_base + free_bit[k];
+			if (clu_free < sbi->num_clusters)
+				return clu_free;
+		}
+		clu_base += 8;
+
+		if (++map_b >= sb->s_blocksize ||
+		    clu_base >= sbi->num_clusters) {
+			if (++map_i >= sbi->map_sectors) {
+				clu_base = 2;
+				map_i = 0;
+			}
+			map_b = 0;
+		}
+	}
+
+	return EOF_CLUSTER;
+}
+
+int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int count = 0;
+	unsigned int i, map_i = 0, map_b = 0;
+	unsigned int total_clus = sbi->num_clusters - 2;
+	unsigned int last_mask = total_clus & 7;
+	unsigned char clu_bits;
+	const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,
+		0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};
+
+	total_clus &= ~last_mask;
+	for (i = 0; i < total_clus; i += 8) {
+		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
+		count += used_bit[clu_bits];
+		if (++map_b >= (unsigned int)sb->s_blocksize) {
+			map_i++;
+			map_b = 0;
+		}
+	}
+
+	if (last_mask) {
+		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
+		clu_bits &= last_bit_mask[last_mask];
+		count += used_bit[clu_bits];
+	}
+
+	*ret_count = count;
+	return 0;
+}
-- 
2.17.1

Re: [PATCH v6 07/13] exfat: add bitmap operations

[Vyacheslav Dubeyko]

On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of bitmap operations for exfat.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
>  fs/exfat/balloc.c | 272
> ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 272 insertions(+)
>  create mode 100644 fs/exfat/balloc.c
> 
> diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
> new file mode 100644
> index 000000000000..d7b70620e349
> --- /dev/null
> +++ b/fs/exfat/balloc.c
> @@ -0,0 +1,272 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#include <linux/blkdev.h>
> +#include <linux/slab.h>
> +#include <linux/buffer_head.h>
> +
> +#include "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +static const unsigned char free_bit[] = {
> +	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0,
> 2,/*  0 ~  19*/
> +	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/*
> 20 ~  39*/
> +	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*
> 40 ~  59*/
> +	0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*
> 60 ~  79*/
> +	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/*
> 80 ~  99*/
> +	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0,
> 3,/*100 ~ 119*/
> +	0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0,
> 2,/*120 ~ 139*/
> +	0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
> 5,/*140 ~ 159*/
> +	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0,
> 2,/*160 ~ 179*/
> +	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0,
> 3,/*180 ~ 199*/
> +	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0,
> 2,/*200 ~ 219*/
> +	0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
> 4,/*220 ~ 239*/
> +	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1,
> 0                /*240 ~ 254*/
> +};
> +
> +static const unsigned char used_bit[] = {
> +	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2,
> 3,/*  0 ~  19*/
> +	2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/*
> 20 ~  39*/
> +	2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/*
> 40 ~  59*/
> +	4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/*
> 60 ~  79*/
> +	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/*
> 80 ~  99*/
> +	3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5,
> 6,/*100 ~ 119*/
> +	4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3,
> 4,/*120 ~ 139*/
> +	3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5,
> 6,/*140 ~ 159*/
> +	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4,
> 5,/*160 ~ 179*/
> +	4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4,
> 5,/*180 ~ 199*/
> +	3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5,
> 6,/*200 ~ 219*/
> +	5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6,
> 7,/*220 ~ 239*/
> +	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7,
> 8             /*240 ~ 255*/
> +};
> +
> +/*
> + *  Allocation Bitmap Management Functions
> + */
> +static int exfat_allocate_bitmap(struct super_block *sb,
> +		struct exfat_dentry *ep)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	long long map_size;
> +	unsigned int i, need_map_size;
> +	sector_t sector;
> +
> +	sbi->map_clu = le32_to_cpu(ep->bitmap_start_clu);
> +	map_size = le64_to_cpu(ep->bitmap_size);
> +	need_map_size = (((sbi->num_clusters - BASE_CLUSTER) - 1) >> 3)
> + 1;

This code is slightly complicated. Why 3 was used here? Maybe it makes
sense to refactor this code and to make it more clear?

> +	if (need_map_size != map_size) {
> +		exfat_msg(sb, KERN_ERR,
> +				"bogus allocation bitmap size(need :
> %u, cur : %lld)",
> +				need_map_size, map_size);
> +		/*
> +		 * Only allowed when bogus allocation
> +		 * bitmap size is large
> +		 */
> +		if (need_map_size > map_size)
> +			return -EIO;
> +	}
> +	sbi->map_sectors = ((need_map_size - 1) >>
> +			(sb->s_blocksize_bits)) + 1;
> +	sbi->vol_amap = kmalloc_array(sbi->map_sectors,
> +				sizeof(struct buffer_head *),
> GFP_KERNEL);
> +	if (!sbi->vol_amap)
> +		return -ENOMEM;
> +
> +	sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
> +	for (i = 0; i < sbi->map_sectors; i++) {
> +		sbi->vol_amap[i] = sb_bread(sb, sector + i);
> +		if (!sbi->vol_amap[i]) {
> +			/* release all buffers and free vol_amap */
> +			int j = 0;
> +
> +			while (j < i)
> +				brelse(sbi->vol_amap[j++]);
> +
> +			kfree(sbi->vol_amap);
> +			sbi->vol_amap = NULL;
> +			return -EIO;
> +		}
> +	}
> +
> +	sbi->pbr_bh = NULL;
> +	return 0;
> +}
> +
> +int exfat_load_bitmap(struct super_block *sb)
> +{
> +	unsigned int i, type;
> +	struct exfat_chain clu;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
> +
> +	while (clu.dir != EOF_CLUSTER) {
> +		for (i = 0; i < sbi->dentries_per_clu; i++) {
> +			struct exfat_dentry *ep;
> +			struct buffer_head *bh;
> +
> +			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
> +			if (!ep)
> +				return -EIO;
> +
> +			type = exfat_get_entry_type(ep);
> +			if (type == TYPE_UNUSED)
> +				break;
> +			if (type != TYPE_BITMAP)
> +				continue;
> +			if (ep->bitmap_flags == 0x0) {
> +				int err;
> +
> +				err = exfat_allocate_bitmap(sb, ep);
> +				brelse(bh);
> +				return err;
> +			}
> +			brelse(bh);
> +		}
> +
> +		if (exfat_get_next_cluster(sb, &clu.dir))
> +			return -EIO;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +void exfat_free_bitmap(struct super_block *sb)
> +{
> +	int i;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	brelse(sbi->pbr_bh);
> +
> +	for (i = 0; i < sbi->map_sectors; i++)
> +		__brelse(sbi->vol_amap[i]);
> +
> +	kfree(sbi->vol_amap);
> +	sbi->vol_amap = NULL;
> +}
> +
> +/*
> + * If the value of "clu" is 0, it means cluster 2 which is the first
> cluster of
> + * the cluster heap.
> + */
> +int exfat_set_bitmap(struct inode *inode, unsigned int clu)
> +{
> +	int i, b;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	i = clu >> (sb->s_blocksize_bits + 3);
> +	b = clu & ((sb->s_blocksize << 3) - 1);

This code looks like the dark magic. I believe it makes sense to
introduce some constant for 3 here.

> +
> +	set_bit_le(b, sbi->vol_amap[i]->b_data);
> +	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));
> +	return 0;
> +}
> +
> +/*
> + * If the value of "clu" is 0, it means cluster 2 which is the first
> cluster of
> + * the cluster heap.
> + */
> +void exfat_clear_bitmap(struct inode *inode, unsigned int clu)
> +{
> +	int i, b;
> +	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	struct exfat_mount_options *opts = &sbi->options;
> +
> +	i = clu >> (sb->s_blocksize_bits + 3);
> +	b = clu & ((sb->s_blocksize << 3) - 1);
> +

Ditto.

> +	clear_bit_le(b, sbi->vol_amap[i]->b_data);
> +	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));
> +
> +	if (opts->discard) {
> +		int ret_discard;
> +
> +		ret_discard = sb_issue_discard(sb,
> +				exfat_cluster_to_sector(sbi, clu + 2),
> +				(1 << sbi->sect_per_clus_bits),
> GFP_NOFS, 0);

Why clu + 2? It's unclear, frankly speaking.

> +
> +		if (ret_discard == -EOPNOTSUPP) {
> +			exfat_msg(sb, KERN_ERR,
> +				"discard not supported by device,
> disabling");
> +			opts->discard = 0;
> +		}
> +	}
> +}
> +
> +/*
> + * If the value of "clu" is 0, it means cluster 2 which is the first
> cluster of
> + * the cluster heap.
> + */
> +unsigned int exfat_test_bitmap(struct super_block *sb, unsigned int
> clu)
> +{
> +	unsigned int i, map_i, map_b;
> +	unsigned int clu_base, clu_free;
> +	unsigned char k, clu_mask;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> +	clu_base = (clu & ~(0x7)) + 2;
> +	clu_mask = (1 << (clu - clu_base + 2)) - 1;
> +

What does 0x7 mean here? Why clu - clu_base + 2? Maybe it need to
introduce some constants and to add some comments?

> +	map_i = clu >> (sb->s_blocksize_bits + 3);
> +	map_b = (clu >> 3) & (unsigned int)(sb->s_blocksize - 1);
> +

Ditto.

> +	for (i = 2; i < sbi->num_clusters; i += 8) {


Why we start from 2 and add 8? Maybe introduce some constants?

> +		k = *(sbi->vol_amap[map_i]->b_data + map_b);
> +		if (clu_mask > 0) {
> +			k |= clu_mask;
> +			clu_mask = 0;
> +		}
> +		if (k < 0xFF) {
> +			clu_free = clu_base + free_bit[k];
> +			if (clu_free < sbi->num_clusters)
> +				return clu_free;
> +		}
> +		clu_base += 8;

Ditto.

> +
> +		if (++map_b >= sb->s_blocksize ||
> +		    clu_base >= sbi->num_clusters) {
> +			if (++map_i >= sbi->map_sectors) {
> +				clu_base = 2;
> +				map_i = 0;
> +			}
> +			map_b = 0;
> +		}
> +	}
> +
> +	return EOF_CLUSTER;
> +}
> +
> +int exfat_count_used_clusters(struct super_block *sb, unsigned int
> *ret_count)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +	unsigned int count = 0;
> +	unsigned int i, map_i = 0, map_b = 0;
> +	unsigned int total_clus = sbi->num_clusters - 2;
> +	unsigned int last_mask = total_clus & 7;

Ditto.

> +	unsigned char clu_bits;
> +	const unsigned char last_bit_mask[] = {0, 0b00000001,
> 0b00000011,
> +		0b00000111, 0b00001111, 0b00011111, 0b00111111,
> 0b01111111};
> +
> +	total_clus &= ~last_mask;
> +	for (i = 0; i < total_clus; i += 8) {

Ditto.

Thanks,
Viacheslav Dubeyko.

> +		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
> +		count += used_bit[clu_bits];
> +		if (++map_b >= (unsigned int)sb->s_blocksize) {
> +			map_i++;
> +			map_b = 0;
> +		}
> +	}
> +
> +	if (last_mask) {
> +		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
> +		clu_bits &= last_bit_mask[last_mask];
> +		count += used_bit[clu_bits];
> +	}
> +
> +	*ret_count = count;
> +	return 0;
> +}

[PATCH v6 08/13] exfat: add exfat cache

[Namjae Jeon]

This adds the implementation of exfat cache.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/cache.c | 325 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 325 insertions(+)
 create mode 100644 fs/exfat/cache.c

diff --git a/fs/exfat/cache.c b/fs/exfat/cache.c
new file mode 100644
index 000000000000..74f9a44471d5
--- /dev/null
+++ b/fs/exfat/cache.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  linux/fs/fat/cache.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *
+ *  Mar 1999. AV. Changed cache, so that it uses the starting cluster instead
+ *	of inode number.
+ *  May 1999. AV. Fixed the bogosity with FAT32 (read "FAT28"). Fscking lusers.
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+#define EXFAT_CACHE_VALID	0
+#define EXFAT_MAX_CACHE		16
+
+struct exfat_cache {
+	struct list_head cache_list;
+	unsigned int nr_contig;	/* number of contiguous clusters */
+	unsigned int fcluster;	/* cluster number in the file. */
+	unsigned int dcluster;	/* cluster number on disk. */
+};
+
+struct exfat_cache_id {
+	unsigned int id;
+	unsigned int nr_contig;
+	unsigned int fcluster;
+	unsigned int dcluster;
+};
+
+static struct kmem_cache *exfat_cachep;
+
+static void exfat_cache_init_once(void *c)
+{
+	struct exfat_cache *cache = (struct exfat_cache *)c;
+
+	INIT_LIST_HEAD(&cache->cache_list);
+}
+
+int exfat_cache_init(void)
+{
+	exfat_cachep = kmem_cache_create("exfat_cache",
+				sizeof(struct exfat_cache),
+				0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
+				exfat_cache_init_once);
+	if (!exfat_cachep)
+		return -ENOMEM;
+	return 0;
+}
+
+void exfat_cache_shutdown(void)
+{
+	if (!exfat_cachep)
+		return;
+	kmem_cache_destroy(exfat_cachep);
+}
+
+void exfat_cache_init_inode(struct inode *inode)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+
+	spin_lock_init(&ei->cache_lru_lock);
+	ei->nr_caches = 0;
+	ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
+	INIT_LIST_HEAD(&ei->cache_lru);
+}
+
+static inline struct exfat_cache *exfat_cache_alloc(void)
+{
+	return kmem_cache_alloc(exfat_cachep, GFP_NOFS);
+}
+
+static inline void exfat_cache_free(struct exfat_cache *cache)
+{
+	WARN_ON(!list_empty(&cache->cache_list));
+	kmem_cache_free(exfat_cachep, cache);
+}
+
+static inline void exfat_cache_update_lru(struct inode *inode,
+		struct exfat_cache *cache)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+
+	if (ei->cache_lru.next != &cache->cache_list)
+		list_move(&cache->cache_list, &ei->cache_lru);
+}
+
+static unsigned int exfat_cache_lookup(struct inode *inode,
+		unsigned int fclus, struct exfat_cache_id *cid,
+		unsigned int *cached_fclus, unsigned int *cached_dclus)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	static struct exfat_cache nohit = { .fcluster = 0, };
+	struct exfat_cache *hit = &nohit, *p;
+	unsigned int offset = EOF_CLUSTER;
+
+	spin_lock(&ei->cache_lru_lock);
+	list_for_each_entry(p, &ei->cache_lru, cache_list) {
+		/* Find the cache of "fclus" or nearest cache. */
+		if (p->fcluster <= fclus && hit->fcluster < p->fcluster) {
+			hit = p;
+			if (hit->fcluster + hit->nr_contig < fclus) {
+				offset = hit->nr_contig;
+			} else {
+				offset = fclus - hit->fcluster;
+				break;
+			}
+		}
+	}
+	if (hit != &nohit) {
+		exfat_cache_update_lru(inode, hit);
+
+		cid->id = ei->cache_valid_id;
+		cid->nr_contig = hit->nr_contig;
+		cid->fcluster = hit->fcluster;
+		cid->dcluster = hit->dcluster;
+		*cached_fclus = cid->fcluster + offset;
+		*cached_dclus = cid->dcluster + offset;
+	}
+	spin_unlock(&ei->cache_lru_lock);
+
+	return offset;
+}
+
+static struct exfat_cache *exfat_cache_merge(struct inode *inode,
+		struct exfat_cache_id *new)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_cache *p;
+
+	list_for_each_entry(p, &ei->cache_lru, cache_list) {
+		/* Find the same part as "new" in cluster-chain. */
+		if (p->fcluster == new->fcluster) {
+			if (new->nr_contig > p->nr_contig)
+				p->nr_contig = new->nr_contig;
+			return p;
+		}
+	}
+	return NULL;
+}
+
+static void exfat_cache_add(struct inode *inode,
+		struct exfat_cache_id *new)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_cache *cache, *tmp;
+
+	if (new->fcluster == EOF_CLUSTER) /* dummy cache */
+		return;
+
+	spin_lock(&ei->cache_lru_lock);
+	if (new->id != EXFAT_CACHE_VALID &&
+	    new->id != ei->cache_valid_id)
+		goto unlock;	/* this cache was invalidated */
+
+	cache = exfat_cache_merge(inode, new);
+	if (cache == NULL) {
+		if (ei->nr_caches < EXFAT_MAX_CACHE) {
+			ei->nr_caches++;
+			spin_unlock(&ei->cache_lru_lock);
+
+			tmp = exfat_cache_alloc();
+			if (!tmp) {
+				spin_lock(&ei->cache_lru_lock);
+				ei->nr_caches--;
+				spin_unlock(&ei->cache_lru_lock);
+				return;
+			}
+
+			spin_lock(&ei->cache_lru_lock);
+			cache = exfat_cache_merge(inode, new);
+			if (cache != NULL) {
+				ei->nr_caches--;
+				exfat_cache_free(tmp);
+				goto out_update_lru;
+			}
+			cache = tmp;
+		} else {
+			struct list_head *p = ei->cache_lru.prev;
+
+			cache = list_entry(p,
+					struct exfat_cache, cache_list);
+		}
+		cache->fcluster = new->fcluster;
+		cache->dcluster = new->dcluster;
+		cache->nr_contig = new->nr_contig;
+	}
+out_update_lru:
+	exfat_cache_update_lru(inode, cache);
+unlock:
+	spin_unlock(&ei->cache_lru_lock);
+}
+
+/*
+ * Cache invalidation occurs rarely, thus the LRU chain is not updated. It
+ * fixes itself after a while.
+ */
+static void __exfat_cache_inval_inode(struct inode *inode)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_cache *cache;
+
+	while (!list_empty(&ei->cache_lru)) {
+		cache = list_entry(ei->cache_lru.next,
+				   struct exfat_cache, cache_list);
+		list_del_init(&cache->cache_list);
+		ei->nr_caches--;
+		exfat_cache_free(cache);
+	}
+	/* Update. The copy of caches before this id is discarded. */
+	ei->cache_valid_id++;
+	if (ei->cache_valid_id == EXFAT_CACHE_VALID)
+		ei->cache_valid_id++;
+}
+
+void exfat_cache_inval_inode(struct inode *inode)
+{
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+
+	spin_lock(&ei->cache_lru_lock);
+	__exfat_cache_inval_inode(inode);
+	spin_unlock(&ei->cache_lru_lock);
+}
+
+static inline int cache_contiguous(struct exfat_cache_id *cid,
+		unsigned int dclus)
+{
+	cid->nr_contig++;
+	return cid->dcluster + cid->nr_contig == dclus;
+}
+
+static inline void cache_init(struct exfat_cache_id *cid,
+		unsigned int fclus, unsigned int dclus)
+{
+	cid->id = EXFAT_CACHE_VALID;
+	cid->fcluster = fclus;
+	cid->dcluster = dclus;
+	cid->nr_contig = 0;
+}
+
+int exfat_get_cluster(struct inode *inode, unsigned int cluster,
+		unsigned int *fclus, unsigned int *dclus,
+		unsigned int *last_dclus, int allow_eof)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int limit = sbi->num_clusters;
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_cache_id cid;
+	unsigned int content;
+
+	if (ei->start_clu == FREE_CLUSTER) {
+		exfat_fs_error(sb,
+			"invalid access to exfat cache (entry 0x%08x)",
+			ei->start_clu);
+		return -EIO;
+	}
+
+	*fclus = 0;
+	*dclus = ei->start_clu;
+	*last_dclus = *dclus;
+
+	/*
+	 * Don`t use exfat_cache if zero offset or non-cluster allocation
+	 */
+	if (cluster == 0 || *dclus == EOF_CLUSTER)
+		return 0;
+
+	cache_init(&cid, EOF_CLUSTER, EOF_CLUSTER);
+
+	if (exfat_cache_lookup(inode, cluster, &cid, fclus, dclus) ==
+			EOF_CLUSTER) {
+		/*
+		 * dummy, always not contiguous
+		 * This is reinitialized by cache_init(), later.
+		 */
+		WARN_ON(cid.id != EXFAT_CACHE_VALID ||
+			cid.fcluster != EOF_CLUSTER ||
+			cid.dcluster != EOF_CLUSTER ||
+			cid.nr_contig != 0);
+	}
+
+	if (*fclus == cluster)
+		return 0;
+
+	while (*fclus < cluster) {
+		/* prevent the infinite loop of cluster chain */
+		if (*fclus > limit) {
+			exfat_fs_error(sb,
+				"detected the cluster chain loop (i_pos %u)",
+				(*fclus));
+			return -EIO;
+		}
+
+		if (exfat_ent_get(sb, *dclus, &content))
+			return -EIO;
+
+		*last_dclus = *dclus;
+		*dclus = content;
+		(*fclus)++;
+
+		if (content == EOF_CLUSTER) {
+			if (!allow_eof) {
+				exfat_fs_error(sb,
+				       "invalid cluster chain (i_pos %u, last_clus 0x%08x is EOF)",
+				       *fclus, (*last_dclus));
+				return -EIO;
+			}
+
+			break;
+		}
+
+		if (!cache_contiguous(&cid, *dclus))
+			cache_init(&cid, *fclus, *dclus);
+	}
+
+	exfat_cache_add(inode, &cid);
+	return 0;
+}
-- 
2.17.1

[PATCH v6 09/13] exfat: add misc operations

[Namjae Jeon]

This adds the implementation of misc operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/misc.c | 240 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 240 insertions(+)
 create mode 100644 fs/exfat/misc.c

diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c
new file mode 100644
index 000000000000..2fa182cd4ff2
--- /dev/null
+++ b/fs/exfat/misc.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Written 1992,1993 by Werner Almesberger
+ *  22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
+ *		 and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+/*
+ * exfat_fs_error reports a file system problem that might indicate fa data
+ * corruption/inconsistency. Depending on 'errors' mount option the
+ * panic() is called, or error message is printed FAT and nothing is done,
+ * or filesystem is remounted read-only (default behavior).
+ * In case the file system is remounted read-only, it can be made writable
+ * again by remounting it.
+ */
+void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
+{
+	struct exfat_mount_options *opts = &EXFAT_SB(sb)->options;
+	va_list args;
+	struct va_format vaf;
+
+	if (report) {
+		va_start(args, fmt);
+		vaf.fmt = fmt;
+		vaf.va = &args;
+		exfat_msg(sb, KERN_ERR, "error, %pV\n", &vaf);
+		va_end(args);
+	}
+
+	if (opts->errors == EXFAT_ERRORS_PANIC) {
+		panic("exFAT-fs (%s): fs panic from previous error\n",
+			sb->s_id);
+	} else if (opts->errors == EXFAT_ERRORS_RO && !sb_rdonly(sb)) {
+		sb->s_flags |= SB_RDONLY;
+		exfat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
+	}
+}
+
+/*
+ * exfat_msg() - print preformated EXFAT specific messages.
+ * All logs except what uses exfat_fs_error() should be written by exfat_msg()
+ */
+void exfat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	/* level means KERN_ pacility level */
+	printk("%sexFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
+	va_end(args);
+}
+
+/* <linux/time.h> externs sys_tz
+ * extern struct timezone sys_tz;
+ */
+#define UNIX_SECS_1980    315532800L
+
+#if BITS_PER_LONG == 64
+#define UNIX_SECS_2108    4354819200L
+#endif
+
+/* days between 1970/01/01 and 1980/01/01 (2 leap days) */
+#define DAYS_DELTA_DECADE    (365 * 10 + 2)
+/* 120 (2100 - 1980) isn't leap year */
+#define NO_LEAP_YEAR_2100    (120)
+#define IS_LEAP_YEAR(y)    (!((y) & 0x3) && (y) != NO_LEAP_YEAR_2100)
+
+#define SECS_PER_MIN    (60)
+#define SECS_PER_HOUR   (60 * SECS_PER_MIN)
+#define SECS_PER_DAY    (24 * SECS_PER_HOUR)
+
+#define MAKE_LEAP_YEAR(leap_year, year)                         \
+	do {                                                    \
+		/* 2100 isn't leap year */                      \
+		if (unlikely(year > NO_LEAP_YEAR_2100))         \
+			leap_year = ((year + 3) / 4) - 1;       \
+		else                                            \
+			leap_year = ((year + 3) / 4);           \
+	} while (0)
+
+/* Linear day numbers of the respective 1sts in non-leap years. */
+static time_t accum_days_in_year[] = {
+	/* Month : N 01  02  03  04  05  06  07  08  09  10  11  12 */
+	0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
+};
+
+/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
+void exfat_time_fat2unix(struct exfat_sb_info *sbi, struct timespec64 *ts,
+		struct exfat_date_time *tp)
+{
+	time_t year = tp->year;
+	time_t ld; /* leap day */
+
+	MAKE_LEAP_YEAR(ld, year);
+
+	if (IS_LEAP_YEAR(year) && (tp->month) > 2)
+		ld++;
+
+	ts->tv_sec =  tp->second  + tp->minute * SECS_PER_MIN
+			+ tp->hour * SECS_PER_HOUR
+			+ (year * 365 + ld + accum_days_in_year[tp->month]
+			+ (tp->day - 1) + DAYS_DELTA_DECADE) * SECS_PER_DAY;
+
+	if (!sbi->options.tz_utc)
+		ts->tv_sec += sys_tz.tz_minuteswest * SECS_PER_MIN;
+
+	ts->tv_nsec = 0;
+}
+
+/* Convert linear UNIX date to a FAT time/date pair. */
+void exfat_time_unix2fat(struct exfat_sb_info *sbi, struct timespec64 *ts,
+		struct exfat_date_time *tp)
+{
+	time_t second = ts->tv_sec;
+	time_t day, month, year;
+	time_t ld; /* leap day */
+
+	if (!sbi->options.tz_utc)
+		second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
+
+	/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
+	if (second < UNIX_SECS_1980) {
+		tp->second  = 0;
+		tp->minute  = 0;
+		tp->hour = 0;
+		tp->day  = 1;
+		tp->month  = 1;
+		tp->year = 0;
+		return;
+	}
+#if (BITS_PER_LONG == 64)
+	if (second >= UNIX_SECS_2108) {
+		tp->second  = 59;
+		tp->minute  = 59;
+		tp->hour = 23;
+		tp->day  = 31;
+		tp->month  = 12;
+		tp->year = 127;
+		return;
+	}
+#endif
+
+	day = second / SECS_PER_DAY - DAYS_DELTA_DECADE;
+	year = day / 365;
+
+	MAKE_LEAP_YEAR(ld, year);
+	if (year * 365 + ld > day)
+		year--;
+
+	MAKE_LEAP_YEAR(ld, year);
+	day -= year * 365 + ld;
+
+	if (IS_LEAP_YEAR(year) && day == accum_days_in_year[3]) {
+		month = 2;
+	} else {
+		if (IS_LEAP_YEAR(year) && day > accum_days_in_year[3])
+			day--;
+		for (month = 1; month < 12; month++) {
+			if (accum_days_in_year[month + 1] > day)
+				break;
+		}
+	}
+	day -= accum_days_in_year[month];
+
+	tp->second  = second % SECS_PER_MIN;
+	tp->minute  = (second / SECS_PER_MIN) % 60;
+	tp->hour = (second / SECS_PER_HOUR) % 24;
+	tp->day  = day + 1;
+	tp->month  = month;
+	tp->year = year;
+}
+
+struct exfat_timestamp *exfat_tm_now(struct exfat_sb_info *sbi,
+		struct exfat_timestamp *tp)
+{
+	struct timespec64 ts;
+	struct exfat_date_time dt;
+
+	ktime_get_real_ts64(&ts);
+	exfat_time_unix2fat(sbi, &ts, &dt);
+
+	tp->year = dt.year;
+	tp->mon = dt.month;
+	tp->day = dt.day;
+	tp->hour = dt.hour;
+	tp->min = dt.minute;
+	tp->sec = dt.second;
+
+	return tp;
+}
+
+unsigned short exfat_calc_chksum_2byte(void *data, int len,
+		unsigned short chksum, int type)
+{
+	int i;
+	unsigned char *c = (unsigned char *)data;
+
+	for (i = 0; i < len; i++, c++) {
+		if (((i == 2) || (i == 3)) && (type == CS_DIR_ENTRY))
+			continue;
+		chksum = (((chksum & 1) << 15) | ((chksum & 0xFFFE) >> 1)) +
+			(unsigned short)*c;
+	}
+	return chksum;
+}
+
+void exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int sync)
+{
+	set_bit(EXFAT_SB_DIRTY, &EXFAT_SB(sb)->s_state);
+	set_buffer_uptodate(bh);
+	mark_buffer_dirty(bh);
+
+	if (sync)
+		sync_dirty_buffer(bh);
+}
+
+void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
+		unsigned int size, unsigned char flags)
+{
+	ec->dir = dir;
+	ec->size = size;
+	ec->flags = flags;
+}
+
+void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec)
+{
+	return exfat_chain_set(dup, ec->dir, ec->size, ec->flags);
+}
-- 
2.17.1

[PATCH v6 10/13] exfat: add nls operations

[Namjae Jeon]

This adds the implementation of nls operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/nls.c | 808 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 808 insertions(+)
 create mode 100644 fs/exfat/nls.c

diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
new file mode 100644
index 000000000000..0c00a4b441be
--- /dev/null
+++ b/fs/exfat/nls.c
@@ -0,0 +1,808 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/string.h>
+#include <linux/nls.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+#include <asm/unaligned.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+/* Upcase tabel macro */
+#define EXFAT_NUM_UPCASE	(2918)
+#define UTBL_COUNT		(0x10000)
+
+/*
+ * Upcase table in compressed format (7.2.5.1 Recommended Up-case Table
+ * in exfat specification, See: https://docs.microsoft.com/en-us/windows/
+ * win32/fileio/exfat-specification).
+ */
+static const unsigned short uni_def_upcase[EXFAT_NUM_UPCASE] = {
+	0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007,
+	0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f,
+	0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017,
+	0x0018, 0x0019, 0x001a, 0x001b, 0x001c, 0x001d, 0x001e, 0x001f,
+	0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
+	0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f,
+	0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
+	0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f,
+	0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
+	0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f,
+	0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
+	0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x005f,
+	0x0060, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
+	0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f,
+	0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
+	0x0058, 0x0059, 0x005a, 0x007b, 0x007c, 0x007d, 0x007e, 0x007f,
+	0x0080, 0x0081, 0x0082, 0x0083, 0x0084, 0x0085, 0x0086, 0x0087,
+	0x0088, 0x0089, 0x008a, 0x008b, 0x008c, 0x008d, 0x008e, 0x008f,
+	0x0090, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096, 0x0097,
+	0x0098, 0x0099, 0x009a, 0x009b, 0x009c, 0x009d, 0x009e, 0x009f,
+	0x00a0, 0x00a1, 0x00a2, 0x00a3, 0x00a4, 0x00a5, 0x00a6, 0x00a7,
+	0x00a8, 0x00a9, 0x00aa, 0x00ab, 0x00ac, 0x00ad, 0x00ae, 0x00af,
+	0x00b0, 0x00b1, 0x00b2, 0x00b3, 0x00b4, 0x00b5, 0x00b6, 0x00b7,
+	0x00b8, 0x00b9, 0x00ba, 0x00bb, 0x00bc, 0x00bd, 0x00be, 0x00bf,
+	0x00c0, 0x00c1, 0x00c2, 0x00c3, 0x00c4, 0x00c5, 0x00c6, 0x00c7,
+	0x00c8, 0x00c9, 0x00ca, 0x00cb, 0x00cc, 0x00cd, 0x00ce, 0x00cf,
+	0x00d0, 0x00d1, 0x00d2, 0x00d3, 0x00d4, 0x00d5, 0x00d6, 0x00d7,
+	0x00d8, 0x00d9, 0x00da, 0x00db, 0x00dc, 0x00dd, 0x00de, 0x00df,
+	0x00c0, 0x00c1, 0x00c2, 0x00c3, 0x00c4, 0x00c5, 0x00c6, 0x00c7,
+	0x00c8, 0x00c9, 0x00ca, 0x00cb, 0x00cc, 0x00cd, 0x00ce, 0x00cf,
+	0x00d0, 0x00d1, 0x00d2, 0x00d3, 0x00d4, 0x00d5, 0x00d6, 0x00f7,
+	0x00d8, 0x00d9, 0x00da, 0x00db, 0x00dc, 0x00dd, 0x00de, 0x0178,
+	0x0100, 0x0100, 0x0102, 0x0102, 0x0104, 0x0104, 0x0106, 0x0106,
+	0x0108, 0x0108, 0x010a, 0x010a, 0x010c, 0x010c, 0x010e, 0x010e,
+	0x0110, 0x0110, 0x0112, 0x0112, 0x0114, 0x0114, 0x0116, 0x0116,
+	0x0118, 0x0118, 0x011a, 0x011a, 0x011c, 0x011c, 0x011e, 0x011e,
+	0x0120, 0x0120, 0x0122, 0x0122, 0x0124, 0x0124, 0x0126, 0x0126,
+	0x0128, 0x0128, 0x012a, 0x012a, 0x012c, 0x012c, 0x012e, 0x012e,
+	0x0130, 0x0131, 0x0132, 0x0132, 0x0134, 0x0134, 0x0136, 0x0136,
+	0x0138, 0x0139, 0x0139, 0x013b, 0x013b, 0x013d, 0x013d, 0x013f,
+	0x013f, 0x0141, 0x0141, 0x0143, 0x0143, 0x0145, 0x0145, 0x0147,
+	0x0147, 0x0149, 0x014a, 0x014a, 0x014c, 0x014c, 0x014e, 0x014e,
+	0x0150, 0x0150, 0x0152, 0x0152, 0x0154, 0x0154, 0x0156, 0x0156,
+	0x0158, 0x0158, 0x015a, 0x015a, 0x015c, 0x015c, 0x015e, 0x015e,
+	0x0160, 0x0160, 0x0162, 0x0162, 0x0164, 0x0164, 0x0166, 0x0166,
+	0x0168, 0x0168, 0x016a, 0x016a, 0x016c, 0x016c, 0x016e, 0x016e,
+	0x0170, 0x0170, 0x0172, 0x0172, 0x0174, 0x0174, 0x0176, 0x0176,
+	0x0178, 0x0179, 0x0179, 0x017b, 0x017b, 0x017d, 0x017d, 0x017f,
+	0x0243, 0x0181, 0x0182, 0x0182, 0x0184, 0x0184, 0x0186, 0x0187,
+	0x0187, 0x0189, 0x018a, 0x018b, 0x018b, 0x018d, 0x018e, 0x018f,
+	0x0190, 0x0191, 0x0191, 0x0193, 0x0194, 0x01f6, 0x0196, 0x0197,
+	0x0198, 0x0198, 0x023d, 0x019b, 0x019c, 0x019d, 0x0220, 0x019f,
+	0x01a0, 0x01a0, 0x01a2, 0x01a2, 0x01a4, 0x01a4, 0x01a6, 0x01a7,
+	0x01a7, 0x01a9, 0x01aa, 0x01ab, 0x01ac, 0x01ac, 0x01ae, 0x01af,
+	0x01af, 0x01b1, 0x01b2, 0x01b3, 0x01b3, 0x01b5, 0x01b5, 0x01b7,
+	0x01b8, 0x01b8, 0x01ba, 0x01bb, 0x01bc, 0x01bc, 0x01be, 0x01f7,
+	0x01c0, 0x01c1, 0x01c2, 0x01c3, 0x01c4, 0x01c5, 0x01c4, 0x01c7,
+	0x01c8, 0x01c7, 0x01ca, 0x01cb, 0x01ca, 0x01cd, 0x01cd, 0x01cf,
+	0x01cf, 0x01d1, 0x01d1, 0x01d3, 0x01d3, 0x01d5, 0x01d5, 0x01d7,
+	0x01d7, 0x01d9, 0x01d9, 0x01db, 0x01db, 0x018e, 0x01de, 0x01de,
+	0x01e0, 0x01e0, 0x01e2, 0x01e2, 0x01e4, 0x01e4, 0x01e6, 0x01e6,
+	0x01e8, 0x01e8, 0x01ea, 0x01ea, 0x01ec, 0x01ec, 0x01ee, 0x01ee,
+	0x01f0, 0x01f1, 0x01f2, 0x01f1, 0x01f4, 0x01f4, 0x01f6, 0x01f7,
+	0x01f8, 0x01f8, 0x01fa, 0x01fa, 0x01fc, 0x01fc, 0x01fe, 0x01fe,
+	0x0200, 0x0200, 0x0202, 0x0202, 0x0204, 0x0204, 0x0206, 0x0206,
+	0x0208, 0x0208, 0x020a, 0x020a, 0x020c, 0x020c, 0x020e, 0x020e,
+	0x0210, 0x0210, 0x0212, 0x0212, 0x0214, 0x0214, 0x0216, 0x0216,
+	0x0218, 0x0218, 0x021a, 0x021a, 0x021c, 0x021c, 0x021e, 0x021e,
+	0x0220, 0x0221, 0x0222, 0x0222, 0x0224, 0x0224, 0x0226, 0x0226,
+	0x0228, 0x0228, 0x022a, 0x022a, 0x022c, 0x022c, 0x022e, 0x022e,
+	0x0230, 0x0230, 0x0232, 0x0232, 0x0234, 0x0235, 0x0236, 0x0237,
+	0x0238, 0x0239, 0x2c65, 0x023b, 0x023b, 0x023d, 0x2c66, 0x023f,
+	0x0240, 0x0241, 0x0241, 0x0243, 0x0244, 0x0245, 0x0246, 0x0246,
+	0x0248, 0x0248, 0x024a, 0x024a, 0x024c, 0x024c, 0x024e, 0x024e,
+	0x0250, 0x0251, 0x0252, 0x0181, 0x0186, 0x0255, 0x0189, 0x018a,
+	0x0258, 0x018f, 0x025a, 0x0190, 0x025c, 0x025d, 0x025e, 0x025f,
+	0x0193, 0x0261, 0x0262, 0x0194, 0x0264, 0x0265, 0x0266, 0x0267,
+	0x0197, 0x0196, 0x026a, 0x2c62, 0x026c, 0x026d, 0x026e, 0x019c,
+	0x0270, 0x0271, 0x019d, 0x0273, 0x0274, 0x019f, 0x0276, 0x0277,
+	0x0278, 0x0279, 0x027a, 0x027b, 0x027c, 0x2c64, 0x027e, 0x027f,
+	0x01a6, 0x0281, 0x0282, 0x01a9, 0x0284, 0x0285, 0x0286, 0x0287,
+	0x01ae, 0x0244, 0x01b1, 0x01b2, 0x0245, 0x028d, 0x028e, 0x028f,
+	0x0290, 0x0291, 0x01b7, 0x0293, 0x0294, 0x0295, 0x0296, 0x0297,
+	0x0298, 0x0299, 0x029a, 0x029b, 0x029c, 0x029d, 0x029e, 0x029f,
+	0x02a0, 0x02a1, 0x02a2, 0x02a3, 0x02a4, 0x02a5, 0x02a6, 0x02a7,
+	0x02a8, 0x02a9, 0x02aa, 0x02ab, 0x02ac, 0x02ad, 0x02ae, 0x02af,
+	0x02b0, 0x02b1, 0x02b2, 0x02b3, 0x02b4, 0x02b5, 0x02b6, 0x02b7,
+	0x02b8, 0x02b9, 0x02ba, 0x02bb, 0x02bc, 0x02bd, 0x02be, 0x02bf,
+	0x02c0, 0x02c1, 0x02c2, 0x02c3, 0x02c4, 0x02c5, 0x02c6, 0x02c7,
+	0x02c8, 0x02c9, 0x02ca, 0x02cb, 0x02cc, 0x02cd, 0x02ce, 0x02cf,
+	0x02d0, 0x02d1, 0x02d2, 0x02d3, 0x02d4, 0x02d5, 0x02d6, 0x02d7,
+	0x02d8, 0x02d9, 0x02da, 0x02db, 0x02dc, 0x02dd, 0x02de, 0x02df,
+	0x02e0, 0x02e1, 0x02e2, 0x02e3, 0x02e4, 0x02e5, 0x02e6, 0x02e7,
+	0x02e8, 0x02e9, 0x02ea, 0x02eb, 0x02ec, 0x02ed, 0x02ee, 0x02ef,
+	0x02f0, 0x02f1, 0x02f2, 0x02f3, 0x02f4, 0x02f5, 0x02f6, 0x02f7,
+	0x02f8, 0x02f9, 0x02fa, 0x02fb, 0x02fc, 0x02fd, 0x02fe, 0x02ff,
+	0x0300, 0x0301, 0x0302, 0x0303, 0x0304, 0x0305, 0x0306, 0x0307,
+	0x0308, 0x0309, 0x030a, 0x030b, 0x030c, 0x030d, 0x030e, 0x030f,
+	0x0310, 0x0311, 0x0312, 0x0313, 0x0314, 0x0315, 0x0316, 0x0317,
+	0x0318, 0x0319, 0x031a, 0x031b, 0x031c, 0x031d, 0x031e, 0x031f,
+	0x0320, 0x0321, 0x0322, 0x0323, 0x0324, 0x0325, 0x0326, 0x0327,
+	0x0328, 0x0329, 0x032a, 0x032b, 0x032c, 0x032d, 0x032e, 0x032f,
+	0x0330, 0x0331, 0x0332, 0x0333, 0x0334, 0x0335, 0x0336, 0x0337,
+	0x0338, 0x0339, 0x033a, 0x033b, 0x033c, 0x033d, 0x033e, 0x033f,
+	0x0340, 0x0341, 0x0342, 0x0343, 0x0344, 0x0345, 0x0346, 0x0347,
+	0x0348, 0x0349, 0x034a, 0x034b, 0x034c, 0x034d, 0x034e, 0x034f,
+	0x0350, 0x0351, 0x0352, 0x0353, 0x0354, 0x0355, 0x0356, 0x0357,
+	0x0358, 0x0359, 0x035a, 0x035b, 0x035c, 0x035d, 0x035e, 0x035f,
+	0x0360, 0x0361, 0x0362, 0x0363, 0x0364, 0x0365, 0x0366, 0x0367,
+	0x0368, 0x0369, 0x036a, 0x036b, 0x036c, 0x036d, 0x036e, 0x036f,
+	0x0370, 0x0371, 0x0372, 0x0373, 0x0374, 0x0375, 0x0376, 0x0377,
+	0x0378, 0x0379, 0x037a, 0x03fd, 0x03fe, 0x03ff, 0x037e, 0x037f,
+	0x0380, 0x0381, 0x0382, 0x0383, 0x0384, 0x0385, 0x0386, 0x0387,
+	0x0388, 0x0389, 0x038a, 0x038b, 0x038c, 0x038d, 0x038e, 0x038f,
+	0x0390, 0x0391, 0x0392, 0x0393, 0x0394, 0x0395, 0x0396, 0x0397,
+	0x0398, 0x0399, 0x039a, 0x039b, 0x039c, 0x039d, 0x039e, 0x039f,
+	0x03a0, 0x03a1, 0x03a2, 0x03a3, 0x03a4, 0x03a5, 0x03a6, 0x03a7,
+	0x03a8, 0x03a9, 0x03aa, 0x03ab, 0x0386, 0x0388, 0x0389, 0x038a,
+	0x03b0, 0x0391, 0x0392, 0x0393, 0x0394, 0x0395, 0x0396, 0x0397,
+	0x0398, 0x0399, 0x039a, 0x039b, 0x039c, 0x039d, 0x039e, 0x039f,
+	0x03a0, 0x03a1, 0x03a3, 0x03a3, 0x03a4, 0x03a5, 0x03a6, 0x03a7,
+	0x03a8, 0x03a9, 0x03aa, 0x03ab, 0x038c, 0x038e, 0x038f, 0x03cf,
+	0x03d0, 0x03d1, 0x03d2, 0x03d3, 0x03d4, 0x03d5, 0x03d6, 0x03d7,
+	0x03d8, 0x03d8, 0x03da, 0x03da, 0x03dc, 0x03dc, 0x03de, 0x03de,
+	0x03e0, 0x03e0, 0x03e2, 0x03e2, 0x03e4, 0x03e4, 0x03e6, 0x03e6,
+	0x03e8, 0x03e8, 0x03ea, 0x03ea, 0x03ec, 0x03ec, 0x03ee, 0x03ee,
+	0x03f0, 0x03f1, 0x03f9, 0x03f3, 0x03f4, 0x03f5, 0x03f6, 0x03f7,
+	0x03f7, 0x03f9, 0x03fa, 0x03fa, 0x03fc, 0x03fd, 0x03fe, 0x03ff,
+	0x0400, 0x0401, 0x0402, 0x0403, 0x0404, 0x0405, 0x0406, 0x0407,
+	0x0408, 0x0409, 0x040a, 0x040b, 0x040c, 0x040d, 0x040e, 0x040f,
+	0x0410, 0x0411, 0x0412, 0x0413, 0x0414, 0x0415, 0x0416, 0x0417,
+	0x0418, 0x0419, 0x041a, 0x041b, 0x041c, 0x041d, 0x041e, 0x041f,
+	0x0420, 0x0421, 0x0422, 0x0423, 0x0424, 0x0425, 0x0426, 0x0427,
+	0x0428, 0x0429, 0x042a, 0x042b, 0x042c, 0x042d, 0x042e, 0x042f,
+	0x0410, 0x0411, 0x0412, 0x0413, 0x0414, 0x0415, 0x0416, 0x0417,
+	0x0418, 0x0419, 0x041a, 0x041b, 0x041c, 0x041d, 0x041e, 0x041f,
+	0x0420, 0x0421, 0x0422, 0x0423, 0x0424, 0x0425, 0x0426, 0x0427,
+	0x0428, 0x0429, 0x042a, 0x042b, 0x042c, 0x042d, 0x042e, 0x042f,
+	0x0400, 0x0401, 0x0402, 0x0403, 0x0404, 0x0405, 0x0406, 0x0407,
+	0x0408, 0x0409, 0x040a, 0x040b, 0x040c, 0x040d, 0x040e, 0x040f,
+	0x0460, 0x0460, 0x0462, 0x0462, 0x0464, 0x0464, 0x0466, 0x0466,
+	0x0468, 0x0468, 0x046a, 0x046a, 0x046c, 0x046c, 0x046e, 0x046e,
+	0x0470, 0x0470, 0x0472, 0x0472, 0x0474, 0x0474, 0x0476, 0x0476,
+	0x0478, 0x0478, 0x047a, 0x047a, 0x047c, 0x047c, 0x047e, 0x047e,
+	0x0480, 0x0480, 0x0482, 0x0483, 0x0484, 0x0485, 0x0486, 0x0487,
+	0x0488, 0x0489, 0x048a, 0x048a, 0x048c, 0x048c, 0x048e, 0x048e,
+	0x0490, 0x0490, 0x0492, 0x0492, 0x0494, 0x0494, 0x0496, 0x0496,
+	0x0498, 0x0498, 0x049a, 0x049a, 0x049c, 0x049c, 0x049e, 0x049e,
+	0x04a0, 0x04a0, 0x04a2, 0x04a2, 0x04a4, 0x04a4, 0x04a6, 0x04a6,
+	0x04a8, 0x04a8, 0x04aa, 0x04aa, 0x04ac, 0x04ac, 0x04ae, 0x04ae,
+	0x04b0, 0x04b0, 0x04b2, 0x04b2, 0x04b4, 0x04b4, 0x04b6, 0x04b6,
+	0x04b8, 0x04b8, 0x04ba, 0x04ba, 0x04bc, 0x04bc, 0x04be, 0x04be,
+	0x04c0, 0x04c1, 0x04c1, 0x04c3, 0x04c3, 0x04c5, 0x04c5, 0x04c7,
+	0x04c7, 0x04c9, 0x04c9, 0x04cb, 0x04cb, 0x04cd, 0x04cd, 0x04c0,
+	0x04d0, 0x04d0, 0x04d2, 0x04d2, 0x04d4, 0x04d4, 0x04d6, 0x04d6,
+	0x04d8, 0x04d8, 0x04da, 0x04da, 0x04dc, 0x04dc, 0x04de, 0x04de,
+	0x04e0, 0x04e0, 0x04e2, 0x04e2, 0x04e4, 0x04e4, 0x04e6, 0x04e6,
+	0x04e8, 0x04e8, 0x04ea, 0x04ea, 0x04ec, 0x04ec, 0x04ee, 0x04ee,
+	0x04f0, 0x04f0, 0x04f2, 0x04f2, 0x04f4, 0x04f4, 0x04f6, 0x04f6,
+	0x04f8, 0x04f8, 0x04fa, 0x04fa, 0x04fc, 0x04fc, 0x04fe, 0x04fe,
+	0x0500, 0x0500, 0x0502, 0x0502, 0x0504, 0x0504, 0x0506, 0x0506,
+	0x0508, 0x0508, 0x050a, 0x050a, 0x050c, 0x050c, 0x050e, 0x050e,
+	0x0510, 0x0510, 0x0512, 0x0512, 0x0514, 0x0515, 0x0516, 0x0517,
+	0x0518, 0x0519, 0x051a, 0x051b, 0x051c, 0x051d, 0x051e, 0x051f,
+	0x0520, 0x0521, 0x0522, 0x0523, 0x0524, 0x0525, 0x0526, 0x0527,
+	0x0528, 0x0529, 0x052a, 0x052b, 0x052c, 0x052d, 0x052e, 0x052f,
+	0x0530, 0x0531, 0x0532, 0x0533, 0x0534, 0x0535, 0x0536, 0x0537,
+	0x0538, 0x0539, 0x053a, 0x053b, 0x053c, 0x053d, 0x053e, 0x053f,
+	0x0540, 0x0541, 0x0542, 0x0543, 0x0544, 0x0545, 0x0546, 0x0547,
+	0x0548, 0x0549, 0x054a, 0x054b, 0x054c, 0x054d, 0x054e, 0x054f,
+	0x0550, 0x0551, 0x0552, 0x0553, 0x0554, 0x0555, 0x0556, 0x0557,
+	0x0558, 0x0559, 0x055a, 0x055b, 0x055c, 0x055d, 0x055e, 0x055f,
+	0x0560, 0x0531, 0x0532, 0x0533, 0x0534, 0x0535, 0x0536, 0x0537,
+	0x0538, 0x0539, 0x053a, 0x053b, 0x053c, 0x053d, 0x053e, 0x053f,
+	0x0540, 0x0541, 0x0542, 0x0543, 0x0544, 0x0545, 0x0546, 0x0547,
+	0x0548, 0x0549, 0x054a, 0x054b, 0x054c, 0x054d, 0x054e, 0x054f,
+	0x0550, 0x0551, 0x0552, 0x0553, 0x0554, 0x0555, 0x0556, 0xffff,
+	0x17f6, 0x2c63, 0x1d7e, 0x1d7f, 0x1d80, 0x1d81, 0x1d82, 0x1d83,
+	0x1d84, 0x1d85, 0x1d86, 0x1d87, 0x1d88, 0x1d89, 0x1d8a, 0x1d8b,
+	0x1d8c, 0x1d8d, 0x1d8e, 0x1d8f, 0x1d90, 0x1d91, 0x1d92, 0x1d93,
+	0x1d94, 0x1d95, 0x1d96, 0x1d97, 0x1d98, 0x1d99, 0x1d9a, 0x1d9b,
+	0x1d9c, 0x1d9d, 0x1d9e, 0x1d9f, 0x1da0, 0x1da1, 0x1da2, 0x1da3,
+	0x1da4, 0x1da5, 0x1da6, 0x1da7, 0x1da8, 0x1da9, 0x1daa, 0x1dab,
+	0x1dac, 0x1dad, 0x1dae, 0x1daf, 0x1db0, 0x1db1, 0x1db2, 0x1db3,
+	0x1db4, 0x1db5, 0x1db6, 0x1db7, 0x1db8, 0x1db9, 0x1dba, 0x1dbb,
+	0x1dbc, 0x1dbd, 0x1dbe, 0x1dbf, 0x1dc0, 0x1dc1, 0x1dc2, 0x1dc3,
+	0x1dc4, 0x1dc5, 0x1dc6, 0x1dc7, 0x1dc8, 0x1dc9, 0x1dca, 0x1dcb,
+	0x1dcc, 0x1dcd, 0x1dce, 0x1dcf, 0x1dd0, 0x1dd1, 0x1dd2, 0x1dd3,
+	0x1dd4, 0x1dd5, 0x1dd6, 0x1dd7, 0x1dd8, 0x1dd9, 0x1dda, 0x1ddb,
+	0x1ddc, 0x1ddd, 0x1dde, 0x1ddf, 0x1de0, 0x1de1, 0x1de2, 0x1de3,
+	0x1de4, 0x1de5, 0x1de6, 0x1de7, 0x1de8, 0x1de9, 0x1dea, 0x1deb,
+	0x1dec, 0x1ded, 0x1dee, 0x1def, 0x1df0, 0x1df1, 0x1df2, 0x1df3,
+	0x1df4, 0x1df5, 0x1df6, 0x1df7, 0x1df8, 0x1df9, 0x1dfa, 0x1dfb,
+	0x1dfc, 0x1dfd, 0x1dfe, 0x1dff, 0x1e00, 0x1e00, 0x1e02, 0x1e02,
+	0x1e04, 0x1e04, 0x1e06, 0x1e06, 0x1e08, 0x1e08, 0x1e0a, 0x1e0a,
+	0x1e0c, 0x1e0c, 0x1e0e, 0x1e0e, 0x1e10, 0x1e10, 0x1e12, 0x1e12,
+	0x1e14, 0x1e14, 0x1e16, 0x1e16, 0x1e18, 0x1e18, 0x1e1a, 0x1e1a,
+	0x1e1c, 0x1e1c, 0x1e1e, 0x1e1e, 0x1e20, 0x1e20, 0x1e22, 0x1e22,
+	0x1e24, 0x1e24, 0x1e26, 0x1e26, 0x1e28, 0x1e28, 0x1e2a, 0x1e2a,
+	0x1e2c, 0x1e2c, 0x1e2e, 0x1e2e, 0x1e30, 0x1e30, 0x1e32, 0x1e32,
+	0x1e34, 0x1e34, 0x1e36, 0x1e36, 0x1e38, 0x1e38, 0x1e3a, 0x1e3a,
+	0x1e3c, 0x1e3c, 0x1e3e, 0x1e3e, 0x1e40, 0x1e40, 0x1e42, 0x1e42,
+	0x1e44, 0x1e44, 0x1e46, 0x1e46, 0x1e48, 0x1e48, 0x1e4a, 0x1e4a,
+	0x1e4c, 0x1e4c, 0x1e4e, 0x1e4e, 0x1e50, 0x1e50, 0x1e52, 0x1e52,
+	0x1e54, 0x1e54, 0x1e56, 0x1e56, 0x1e58, 0x1e58, 0x1e5a, 0x1e5a,
+	0x1e5c, 0x1e5c, 0x1e5e, 0x1e5e, 0x1e60, 0x1e60, 0x1e62, 0x1e62,
+	0x1e64, 0x1e64, 0x1e66, 0x1e66, 0x1e68, 0x1e68, 0x1e6a, 0x1e6a,
+	0x1e6c, 0x1e6c, 0x1e6e, 0x1e6e, 0x1e70, 0x1e70, 0x1e72, 0x1e72,
+	0x1e74, 0x1e74, 0x1e76, 0x1e76, 0x1e78, 0x1e78, 0x1e7a, 0x1e7a,
+	0x1e7c, 0x1e7c, 0x1e7e, 0x1e7e, 0x1e80, 0x1e80, 0x1e82, 0x1e82,
+	0x1e84, 0x1e84, 0x1e86, 0x1e86, 0x1e88, 0x1e88, 0x1e8a, 0x1e8a,
+	0x1e8c, 0x1e8c, 0x1e8e, 0x1e8e, 0x1e90, 0x1e90, 0x1e92, 0x1e92,
+	0x1e94, 0x1e94, 0x1e96, 0x1e97, 0x1e98, 0x1e99, 0x1e9a, 0x1e9b,
+	0x1e9c, 0x1e9d, 0x1e9e, 0x1e9f, 0x1ea0, 0x1ea0, 0x1ea2, 0x1ea2,
+	0x1ea4, 0x1ea4, 0x1ea6, 0x1ea6, 0x1ea8, 0x1ea8, 0x1eaa, 0x1eaa,
+	0x1eac, 0x1eac, 0x1eae, 0x1eae, 0x1eb0, 0x1eb0, 0x1eb2, 0x1eb2,
+	0x1eb4, 0x1eb4, 0x1eb6, 0x1eb6, 0x1eb8, 0x1eb8, 0x1eba, 0x1eba,
+	0x1ebc, 0x1ebc, 0x1ebe, 0x1ebe, 0x1ec0, 0x1ec0, 0x1ec2, 0x1ec2,
+	0x1ec4, 0x1ec4, 0x1ec6, 0x1ec6, 0x1ec8, 0x1ec8, 0x1eca, 0x1eca,
+	0x1ecc, 0x1ecc, 0x1ece, 0x1ece, 0x1ed0, 0x1ed0, 0x1ed2, 0x1ed2,
+	0x1ed4, 0x1ed4, 0x1ed6, 0x1ed6, 0x1ed8, 0x1ed8, 0x1eda, 0x1eda,
+	0x1edc, 0x1edc, 0x1ede, 0x1ede, 0x1ee0, 0x1ee0, 0x1ee2, 0x1ee2,
+	0x1ee4, 0x1ee4, 0x1ee6, 0x1ee6, 0x1ee8, 0x1ee8, 0x1eea, 0x1eea,
+	0x1eec, 0x1eec, 0x1eee, 0x1eee, 0x1ef0, 0x1ef0, 0x1ef2, 0x1ef2,
+	0x1ef4, 0x1ef4, 0x1ef6, 0x1ef6, 0x1ef8, 0x1ef8, 0x1efa, 0x1efb,
+	0x1efc, 0x1efd, 0x1efe, 0x1eff, 0x1f08, 0x1f09, 0x1f0a, 0x1f0b,
+	0x1f0c, 0x1f0d, 0x1f0e, 0x1f0f, 0x1f08, 0x1f09, 0x1f0a, 0x1f0b,
+	0x1f0c, 0x1f0d, 0x1f0e, 0x1f0f, 0x1f18, 0x1f19, 0x1f1a, 0x1f1b,
+	0x1f1c, 0x1f1d, 0x1f16, 0x1f17, 0x1f18, 0x1f19, 0x1f1a, 0x1f1b,
+	0x1f1c, 0x1f1d, 0x1f1e, 0x1f1f, 0x1f28, 0x1f29, 0x1f2a, 0x1f2b,
+	0x1f2c, 0x1f2d, 0x1f2e, 0x1f2f, 0x1f28, 0x1f29, 0x1f2a, 0x1f2b,
+	0x1f2c, 0x1f2d, 0x1f2e, 0x1f2f, 0x1f38, 0x1f39, 0x1f3a, 0x1f3b,
+	0x1f3c, 0x1f3d, 0x1f3e, 0x1f3f, 0x1f38, 0x1f39, 0x1f3a, 0x1f3b,
+	0x1f3c, 0x1f3d, 0x1f3e, 0x1f3f, 0x1f48, 0x1f49, 0x1f4a, 0x1f4b,
+	0x1f4c, 0x1f4d, 0x1f46, 0x1f47, 0x1f48, 0x1f49, 0x1f4a, 0x1f4b,
+	0x1f4c, 0x1f4d, 0x1f4e, 0x1f4f, 0x1f50, 0x1f59, 0x1f52, 0x1f5b,
+	0x1f54, 0x1f5d, 0x1f56, 0x1f5f, 0x1f58, 0x1f59, 0x1f5a, 0x1f5b,
+	0x1f5c, 0x1f5d, 0x1f5e, 0x1f5f, 0x1f68, 0x1f69, 0x1f6a, 0x1f6b,
+	0x1f6c, 0x1f6d, 0x1f6e, 0x1f6f, 0x1f68, 0x1f69, 0x1f6a, 0x1f6b,
+	0x1f6c, 0x1f6d, 0x1f6e, 0x1f6f, 0x1fba, 0x1fbb, 0x1fc8, 0x1fc9,
+	0x1fca, 0x1fcb, 0x1fda, 0x1fdb, 0x1ff8, 0x1ff9, 0x1fea, 0x1feb,
+	0x1ffa, 0x1ffb, 0x1f7e, 0x1f7f, 0x1f88, 0x1f89, 0x1f8a, 0x1f8b,
+	0x1f8c, 0x1f8d, 0x1f8e, 0x1f8f, 0x1f88, 0x1f89, 0x1f8a, 0x1f8b,
+	0x1f8c, 0x1f8d, 0x1f8e, 0x1f8f, 0x1f98, 0x1f99, 0x1f9a, 0x1f9b,
+	0x1f9c, 0x1f9d, 0x1f9e, 0x1f9f, 0x1f98, 0x1f99, 0x1f9a, 0x1f9b,
+	0x1f9c, 0x1f9d, 0x1f9e, 0x1f9f, 0x1fa8, 0x1fa9, 0x1faa, 0x1fab,
+	0x1fac, 0x1fad, 0x1fae, 0x1faf, 0x1fa8, 0x1fa9, 0x1faa, 0x1fab,
+	0x1fac, 0x1fad, 0x1fae, 0x1faf, 0x1fb8, 0x1fb9, 0x1fb2, 0x1fbc,
+	0x1fb4, 0x1fb5, 0x1fb6, 0x1fb7, 0x1fb8, 0x1fb9, 0x1fba, 0x1fbb,
+	0x1fbc, 0x1fbd, 0x1fbe, 0x1fbf, 0x1fc0, 0x1fc1, 0x1fc2, 0x1fc3,
+	0x1fc4, 0x1fc5, 0x1fc6, 0x1fc7, 0x1fc8, 0x1fc9, 0x1fca, 0x1fcb,
+	0x1fc3, 0x1fcd, 0x1fce, 0x1fcf, 0x1fd8, 0x1fd9, 0x1fd2, 0x1fd3,
+	0x1fd4, 0x1fd5, 0x1fd6, 0x1fd7, 0x1fd8, 0x1fd9, 0x1fda, 0x1fdb,
+	0x1fdc, 0x1fdd, 0x1fde, 0x1fdf, 0x1fe8, 0x1fe9, 0x1fe2, 0x1fe3,
+	0x1fe4, 0x1fec, 0x1fe6, 0x1fe7, 0x1fe8, 0x1fe9, 0x1fea, 0x1feb,
+	0x1fec, 0x1fed, 0x1fee, 0x1fef, 0x1ff0, 0x1ff1, 0x1ff2, 0x1ff3,
+	0x1ff4, 0x1ff5, 0x1ff6, 0x1ff7, 0x1ff8, 0x1ff9, 0x1ffa, 0x1ffb,
+	0x1ff3, 0x1ffd, 0x1ffe, 0x1fff, 0x2000, 0x2001, 0x2002, 0x2003,
+	0x2004, 0x2005, 0x2006, 0x2007, 0x2008, 0x2009, 0x200a, 0x200b,
+	0x200c, 0x200d, 0x200e, 0x200f, 0x2010, 0x2011, 0x2012, 0x2013,
+	0x2014, 0x2015, 0x2016, 0x2017, 0x2018, 0x2019, 0x201a, 0x201b,
+	0x201c, 0x201d, 0x201e, 0x201f, 0x2020, 0x2021, 0x2022, 0x2023,
+	0x2024, 0x2025, 0x2026, 0x2027, 0x2028, 0x2029, 0x202a, 0x202b,
+	0x202c, 0x202d, 0x202e, 0x202f, 0x2030, 0x2031, 0x2032, 0x2033,
+	0x2034, 0x2035, 0x2036, 0x2037, 0x2038, 0x2039, 0x203a, 0x203b,
+	0x203c, 0x203d, 0x203e, 0x203f, 0x2040, 0x2041, 0x2042, 0x2043,
+	0x2044, 0x2045, 0x2046, 0x2047, 0x2048, 0x2049, 0x204a, 0x204b,
+	0x204c, 0x204d, 0x204e, 0x204f, 0x2050, 0x2051, 0x2052, 0x2053,
+	0x2054, 0x2055, 0x2056, 0x2057, 0x2058, 0x2059, 0x205a, 0x205b,
+	0x205c, 0x205d, 0x205e, 0x205f, 0x2060, 0x2061, 0x2062, 0x2063,
+	0x2064, 0x2065, 0x2066, 0x2067, 0x2068, 0x2069, 0x206a, 0x206b,
+	0x206c, 0x206d, 0x206e, 0x206f, 0x2070, 0x2071, 0x2072, 0x2073,
+	0x2074, 0x2075, 0x2076, 0x2077, 0x2078, 0x2079, 0x207a, 0x207b,
+	0x207c, 0x207d, 0x207e, 0x207f, 0x2080, 0x2081, 0x2082, 0x2083,
+	0x2084, 0x2085, 0x2086, 0x2087, 0x2088, 0x2089, 0x208a, 0x208b,
+	0x208c, 0x208d, 0x208e, 0x208f, 0x2090, 0x2091, 0x2092, 0x2093,
+	0x2094, 0x2095, 0x2096, 0x2097, 0x2098, 0x2099, 0x209a, 0x209b,
+	0x209c, 0x209d, 0x209e, 0x209f, 0x20a0, 0x20a1, 0x20a2, 0x20a3,
+	0x20a4, 0x20a5, 0x20a6, 0x20a7, 0x20a8, 0x20a9, 0x20aa, 0x20ab,
+	0x20ac, 0x20ad, 0x20ae, 0x20af, 0x20b0, 0x20b1, 0x20b2, 0x20b3,
+	0x20b4, 0x20b5, 0x20b6, 0x20b7, 0x20b8, 0x20b9, 0x20ba, 0x20bb,
+	0x20bc, 0x20bd, 0x20be, 0x20bf, 0x20c0, 0x20c1, 0x20c2, 0x20c3,
+	0x20c4, 0x20c5, 0x20c6, 0x20c7, 0x20c8, 0x20c9, 0x20ca, 0x20cb,
+	0x20cc, 0x20cd, 0x20ce, 0x20cf, 0x20d0, 0x20d1, 0x20d2, 0x20d3,
+	0x20d4, 0x20d5, 0x20d6, 0x20d7, 0x20d8, 0x20d9, 0x20da, 0x20db,
+	0x20dc, 0x20dd, 0x20de, 0x20df, 0x20e0, 0x20e1, 0x20e2, 0x20e3,
+	0x20e4, 0x20e5, 0x20e6, 0x20e7, 0x20e8, 0x20e9, 0x20ea, 0x20eb,
+	0x20ec, 0x20ed, 0x20ee, 0x20ef, 0x20f0, 0x20f1, 0x20f2, 0x20f3,
+	0x20f4, 0x20f5, 0x20f6, 0x20f7, 0x20f8, 0x20f9, 0x20fa, 0x20fb,
+	0x20fc, 0x20fd, 0x20fe, 0x20ff, 0x2100, 0x2101, 0x2102, 0x2103,
+	0x2104, 0x2105, 0x2106, 0x2107, 0x2108, 0x2109, 0x210a, 0x210b,
+	0x210c, 0x210d, 0x210e, 0x210f, 0x2110, 0x2111, 0x2112, 0x2113,
+	0x2114, 0x2115, 0x2116, 0x2117, 0x2118, 0x2119, 0x211a, 0x211b,
+	0x211c, 0x211d, 0x211e, 0x211f, 0x2120, 0x2121, 0x2122, 0x2123,
+	0x2124, 0x2125, 0x2126, 0x2127, 0x2128, 0x2129, 0x212a, 0x212b,
+	0x212c, 0x212d, 0x212e, 0x212f, 0x2130, 0x2131, 0x2132, 0x2133,
+	0x2134, 0x2135, 0x2136, 0x2137, 0x2138, 0x2139, 0x213a, 0x213b,
+	0x213c, 0x213d, 0x213e, 0x213f, 0x2140, 0x2141, 0x2142, 0x2143,
+	0x2144, 0x2145, 0x2146, 0x2147, 0x2148, 0x2149, 0x214a, 0x214b,
+	0x214c, 0x214d, 0x2132, 0x214f, 0x2150, 0x2151, 0x2152, 0x2153,
+	0x2154, 0x2155, 0x2156, 0x2157, 0x2158, 0x2159, 0x215a, 0x215b,
+	0x215c, 0x215d, 0x215e, 0x215f, 0x2160, 0x2161, 0x2162, 0x2163,
+	0x2164, 0x2165, 0x2166, 0x2167, 0x2168, 0x2169, 0x216a, 0x216b,
+	0x216c, 0x216d, 0x216e, 0x216f, 0x2160, 0x2161, 0x2162, 0x2163,
+	0x2164, 0x2165, 0x2166, 0x2167, 0x2168, 0x2169, 0x216a, 0x216b,
+	0x216c, 0x216d, 0x216e, 0x216f, 0x2180, 0x2181, 0x2182, 0x2183,
+	0x2183, 0xffff, 0x034b, 0x24b6, 0x24b7, 0x24b8, 0x24b9, 0x24ba,
+	0x24bb, 0x24bc, 0x24bd, 0x24be, 0x24bf, 0x24c0, 0x24c1, 0x24c2,
+	0x24c3, 0x24c4, 0x24c5, 0x24c6, 0x24c7, 0x24c8, 0x24c9, 0x24ca,
+	0x24cb, 0x24cc, 0x24cd, 0x24ce, 0x24cf, 0xffff, 0x0746, 0x2c00,
+	0x2c01, 0x2c02, 0x2c03, 0x2c04, 0x2c05, 0x2c06, 0x2c07, 0x2c08,
+	0x2c09, 0x2c0a, 0x2c0b, 0x2c0c, 0x2c0d, 0x2c0e, 0x2c0f, 0x2c10,
+	0x2c11, 0x2c12, 0x2c13, 0x2c14, 0x2c15, 0x2c16, 0x2c17, 0x2c18,
+	0x2c19, 0x2c1a, 0x2c1b, 0x2c1c, 0x2c1d, 0x2c1e, 0x2c1f, 0x2c20,
+	0x2c21, 0x2c22, 0x2c23, 0x2c24, 0x2c25, 0x2c26, 0x2c27, 0x2c28,
+	0x2c29, 0x2c2a, 0x2c2b, 0x2c2c, 0x2c2d, 0x2c2e, 0x2c5f, 0x2c60,
+	0x2c60, 0x2c62, 0x2c63, 0x2c64, 0x2c65, 0x2c66, 0x2c67, 0x2c67,
+	0x2c69, 0x2c69, 0x2c6b, 0x2c6b, 0x2c6d, 0x2c6e, 0x2c6f, 0x2c70,
+	0x2c71, 0x2c72, 0x2c73, 0x2c74, 0x2c75, 0x2c75, 0x2c77, 0x2c78,
+	0x2c79, 0x2c7a, 0x2c7b, 0x2c7c, 0x2c7d, 0x2c7e, 0x2c7f, 0x2c80,
+	0x2c80, 0x2c82, 0x2c82, 0x2c84, 0x2c84, 0x2c86, 0x2c86, 0x2c88,
+	0x2c88, 0x2c8a, 0x2c8a, 0x2c8c, 0x2c8c, 0x2c8e, 0x2c8e, 0x2c90,
+	0x2c90, 0x2c92, 0x2c92, 0x2c94, 0x2c94, 0x2c96, 0x2c96, 0x2c98,
+	0x2c98, 0x2c9a, 0x2c9a, 0x2c9c, 0x2c9c, 0x2c9e, 0x2c9e, 0x2ca0,
+	0x2ca0, 0x2ca2, 0x2ca2, 0x2ca4, 0x2ca4, 0x2ca6, 0x2ca6, 0x2ca8,
+	0x2ca8, 0x2caa, 0x2caa, 0x2cac, 0x2cac, 0x2cae, 0x2cae, 0x2cb0,
+	0x2cb0, 0x2cb2, 0x2cb2, 0x2cb4, 0x2cb4, 0x2cb6, 0x2cb6, 0x2cb8,
+	0x2cb8, 0x2cba, 0x2cba, 0x2cbc, 0x2cbc, 0x2cbe, 0x2cbe, 0x2cc0,
+	0x2cc0, 0x2cc2, 0x2cc2, 0x2cc4, 0x2cc4, 0x2cc6, 0x2cc6, 0x2cc8,
+	0x2cc8, 0x2cca, 0x2cca, 0x2ccc, 0x2ccc, 0x2cce, 0x2cce, 0x2cd0,
+	0x2cd0, 0x2cd2, 0x2cd2, 0x2cd4, 0x2cd4, 0x2cd6, 0x2cd6, 0x2cd8,
+	0x2cd8, 0x2cda, 0x2cda, 0x2cdc, 0x2cdc, 0x2cde, 0x2cde, 0x2ce0,
+	0x2ce0, 0x2ce2, 0x2ce2, 0x2ce4, 0x2ce5, 0x2ce6, 0x2ce7, 0x2ce8,
+	0x2ce9, 0x2cea, 0x2ceb, 0x2cec, 0x2ced, 0x2cee, 0x2cef, 0x2cf0,
+	0x2cf1, 0x2cf2, 0x2cf3, 0x2cf4, 0x2cf5, 0x2cf6, 0x2cf7, 0x2cf8,
+	0x2cf9, 0x2cfa, 0x2cfb, 0x2cfc, 0x2cfd, 0x2cfe, 0x2cff, 0x10a0,
+	0x10a1, 0x10a2, 0x10a3, 0x10a4, 0x10a5, 0x10a6, 0x10a7, 0x10a8,
+	0x10a9, 0x10aa, 0x10ab, 0x10ac, 0x10ad, 0x10ae, 0x10af, 0x10b0,
+	0x10b1, 0x10b2, 0x10b3, 0x10b4, 0x10b5, 0x10b6, 0x10b7, 0x10b8,
+	0x10b9, 0x10ba, 0x10bb, 0x10bc, 0x10bd, 0x10be, 0x10bf, 0x10c0,
+	0x10c1, 0x10c2, 0x10c3, 0x10c4, 0x10c5, 0xffff, 0xd21b, 0xff21,
+	0xff22, 0xff23, 0xff24, 0xff25, 0xff26, 0xff27, 0xff28, 0xff29,
+	0xff2a, 0xff2b, 0xff2c, 0xff2d, 0xff2e, 0xff2f, 0xff30, 0xff31,
+	0xff32, 0xff33, 0xff34, 0xff35, 0xff36, 0xff37, 0xff38, 0xff39,
+	0xff3a, 0xff5b, 0xff5c, 0xff5d, 0xff5e, 0xff5f, 0xff60, 0xff61,
+	0xff62, 0xff63, 0xff64, 0xff65, 0xff66, 0xff67, 0xff68, 0xff69,
+	0xff6a, 0xff6b, 0xff6c, 0xff6d, 0xff6e, 0xff6f, 0xff70, 0xff71,
+	0xff72, 0xff73, 0xff74, 0xff75, 0xff76, 0xff77, 0xff78, 0xff79,
+	0xff7a, 0xff7b, 0xff7c, 0xff7d, 0xff7e, 0xff7f, 0xff80, 0xff81,
+	0xff82, 0xff83, 0xff84, 0xff85, 0xff86, 0xff87, 0xff88, 0xff89,
+	0xff8a, 0xff8b, 0xff8c, 0xff8d, 0xff8e, 0xff8f, 0xff90, 0xff91,
+	0xff92, 0xff93, 0xff94, 0xff95, 0xff96, 0xff97, 0xff98, 0xff99,
+	0xff9a, 0xff9b, 0xff9c, 0xff9d, 0xff9e, 0xff9f, 0xffa0, 0xffa1,
+	0xffa2, 0xffa3, 0xffa4, 0xffa5, 0xffa6, 0xffa7, 0xffa8, 0xffa9,
+	0xffaa, 0xffab, 0xffac, 0xffad, 0xffae, 0xffaf, 0xffb0, 0xffb1,
+	0xffb2, 0xffb3, 0xffb4, 0xffb5, 0xffb6, 0xffb7, 0xffb8, 0xffb9,
+	0xffba, 0xffbb, 0xffbc, 0xffbd, 0xffbe, 0xffbf, 0xffc0, 0xffc1,
+	0xffc2, 0xffc3, 0xffc4, 0xffc5, 0xffc6, 0xffc7, 0xffc8, 0xffc9,
+	0xffca, 0xffcb, 0xffcc, 0xffcd, 0xffce, 0xffcf, 0xffd0, 0xffd1,
+	0xffd2, 0xffd3, 0xffd4, 0xffd5, 0xffd6, 0xffd7, 0xffd8, 0xffd9,
+	0xffda, 0xffdb, 0xffdc, 0xffdd, 0xffde, 0xffdf, 0xffe0, 0xffe1,
+	0xffe2, 0xffe3, 0xffe4, 0xffe5, 0xffe6, 0xffe7, 0xffe8, 0xffe9,
+	0xffea, 0xffeb, 0xffec, 0xffed, 0xffee, 0xffef, 0xfff0, 0xfff1,
+	0xfff2, 0xfff3, 0xfff4, 0xfff5, 0xfff6, 0xfff7, 0xfff8, 0xfff9,
+	0xfffa, 0xfffb, 0xfffc, 0xfffd, 0xfffe, 0xffff,
+};
+
+/*
+ * Allow full-width illegal characters :
+ * "MS windows 7" supports full-width-invalid-name-characters.
+ * So we should check half-width-invalid-name-characters(ASCII) only
+ * for compatibility.
+ *
+ * " * / : < > ? \ |
+ *
+ * patch 1.2.0
+ */
+static unsigned short bad_uni_chars[] = {
+	0x0022,         0x002A, 0x002F, 0x003A,
+	0x003C, 0x003E, 0x003F, 0x005C, 0x007C,
+	0
+};
+
+static int exfat_convert_ch_to_uni(struct nls_table *nls,
+		const unsigned char *ch, unsigned short *uni, int *lossy)
+{
+	int len;
+
+	*uni = 0x0;
+
+	if (ch[0] < 0x80) {
+		*uni = ch[0];
+		return 1;
+	}
+
+	len = nls->char2uni(ch, MAX_CHARSET_SIZE, uni);
+	if (len < 0) {
+		/* conversion failed */
+		if (lossy != NULL)
+			*lossy |= NLS_NAME_LOSSY;
+		*uni = '_';
+		if (!strcmp(nls->charset, "utf8"))
+			return 1;
+		return 2;
+	}
+	return len;
+}
+
+static int exfat_convert_uni_to_ch(struct nls_table *nls, unsigned short uni,
+		unsigned char *ch, int *lossy)
+{
+	int len;
+
+	ch[0] = 0x0;
+
+	if (uni < 0x0080) {
+		ch[0] = uni;
+		return 1;
+	}
+
+	len = nls->uni2char(uni, ch, MAX_CHARSET_SIZE);
+	if (len < 0) {
+		/* conversion failed */
+		if (lossy != NULL)
+			*lossy |= NLS_NAME_LOSSY;
+		ch[0] = '_';
+		return 1;
+	}
+	return len;
+}
+
+static unsigned short exfat_nls_upper(struct super_block *sb, unsigned short a)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!sbi->options.case_sensitive && sbi->vol_utbl[a])
+		return sbi->vol_utbl[a];
+	return a;
+}
+
+static unsigned short *exfat_nls_wstrchr(unsigned short *str,
+		unsigned short wchar)
+{
+	while (*str) {
+		if (*(str++) == wchar)
+			return str;
+	}
+	return NULL;
+}
+
+int exfat_nls_cmp_uniname(struct super_block *sb, unsigned short *a,
+		unsigned short *b)
+{
+	int i;
+
+	for (i = 0; i < MAX_NAME_LENGTH; i++, a++, b++) {
+		if (exfat_nls_upper(sb, *a) != exfat_nls_upper(sb, *b))
+			return 1;
+		if (*a == 0x0)
+			return 0;
+	}
+	return 0;
+}
+
+static int __exfat_nls_utf16s_to_vfsname(struct super_block *sb,
+		struct exfat_uni_name *p_uniname, unsigned char *p_cstring,
+		int buflen)
+{
+	int len;
+	const unsigned short *uniname = p_uniname->name;
+
+	/* always len >= 0 */
+	len = utf16s_to_utf8s(uniname, MAX_NAME_LENGTH, UTF16_HOST_ENDIAN,
+		p_cstring, buflen);
+	p_cstring[len] = '\0';
+	return len;
+}
+
+static int __exfat_nls_vfsname_to_utf16s(struct super_block *sb,
+		const unsigned char *p_cstring, const int len,
+		struct exfat_uni_name *p_uniname, int *p_lossy)
+{
+	int i, unilen, lossy = NLS_NAME_NO_LOSSY;
+	unsigned short upname[MAX_NAME_LENGTH + 1];
+	unsigned short *uniname = p_uniname->name;
+
+	WARN_ON(!len);
+
+	unilen = utf8s_to_utf16s(p_cstring, len, UTF16_HOST_ENDIAN,
+			(wchar_t *)uniname, MAX_NAME_LENGTH + 2);
+	if (unilen < 0) {
+		exfat_msg(sb, KERN_ERR,
+			"failed to vfsname_to_utf16(err : %d) vfsnamelen : %d",
+			unilen, len);
+		return unilen;
+	}
+
+	if (unilen > MAX_NAME_LENGTH) {
+		exfat_msg(sb, KERN_ERR,
+			"failed to vfsname_to_utf16(estr:ENAMETOOLONG) vfsnamelen : %d, unilen : %d > %d",
+			len, unilen, MAX_NAME_LENGTH);
+		return -ENAMETOOLONG;
+	}
+
+	p_uniname->name_len = unilen & 0xFF;
+
+	for (i = 0; i < unilen; i++) {
+		if (*uniname < 0x0020 ||
+		    exfat_nls_wstrchr(bad_uni_chars, *uniname))
+			lossy |= NLS_NAME_LOSSY;
+
+		upname[i] = exfat_nls_upper(sb, *uniname);
+		uniname++;
+	}
+
+	*uniname = '\0';
+	p_uniname->name_len = unilen;
+	p_uniname->name_hash = exfat_calc_chksum_2byte(upname, unilen << 1, 0,
+			CS_DEFAULT);
+
+	if (p_lossy)
+		*p_lossy = lossy;
+	return unilen;
+}
+
+static int __exfat_nls_uni16s_to_vfsname(struct super_block *sb,
+		struct exfat_uni_name *p_uniname, unsigned char *p_cstring,
+		int buflen)
+{
+	int i, j, len, out_len = 0;
+	unsigned char buf[MAX_CHARSET_SIZE];
+	const unsigned short *uniname = p_uniname->name;
+	struct nls_table *nls = EXFAT_SB(sb)->nls_io;
+
+	i = 0;
+	while (i < MAX_NAME_LENGTH && out_len < (buflen - 1)) {
+		if (*uniname == '\0')
+			break;
+
+		len = exfat_convert_uni_to_ch(nls, *uniname, buf, NULL);
+		if (out_len + len >= buflen)
+			len = buflen - 1 - out_len;
+		out_len += len;
+
+		if (len > 1) {
+			for (j = 0; j < len; j++)
+				*p_cstring++ = buf[j];
+		} else { /* len == 1 */
+			*p_cstring++ = *buf;
+		}
+
+		uniname++;
+		i++;
+	}
+
+	*p_cstring = '\0';
+	return out_len;
+}
+
+static int __exfat_nls_vfsname_to_uni16s(struct super_block *sb,
+		const unsigned char *p_cstring, const int len,
+		struct exfat_uni_name *p_uniname, int *p_lossy)
+{
+	int i = 0, unilen = 0, lossy = NLS_NAME_NO_LOSSY;
+	unsigned short upname[MAX_NAME_LENGTH + 1];
+	unsigned short *uniname = p_uniname->name;
+	struct nls_table *nls = EXFAT_SB(sb)->nls_io;
+
+	WARN_ON(!len);
+
+	while (unilen < MAX_NAME_LENGTH && i < len) {
+		i += exfat_convert_ch_to_uni(nls, p_cstring + i, uniname,
+				&lossy);
+
+		if (*uniname < 0x0020 ||
+		    exfat_nls_wstrchr(bad_uni_chars, *uniname))
+			lossy |= NLS_NAME_LOSSY;
+
+		upname[unilen] = exfat_nls_upper(sb, *uniname);
+		uniname++;
+		unilen++;
+	}
+
+	if (p_cstring[i] != '\0')
+		lossy |= NLS_NAME_OVERLEN;
+
+	*uniname = '\0';
+	p_uniname->name_len = unilen;
+	p_uniname->name_hash = exfat_calc_chksum_2byte(upname, unilen << 1, 0,
+			CS_DEFAULT);
+
+	if (p_lossy)
+		*p_lossy = lossy;
+	return unilen;
+}
+
+int exfat_nls_uni16s_to_vfsname(struct super_block *sb,
+		struct exfat_uni_name *uniname, unsigned char *p_cstring,
+		int buflen)
+{
+	if (EXFAT_SB(sb)->options.utf8)
+		return __exfat_nls_utf16s_to_vfsname(sb, uniname, p_cstring,
+				buflen);
+	return __exfat_nls_uni16s_to_vfsname(sb, uniname, p_cstring, buflen);
+}
+
+int exfat_nls_vfsname_to_uni16s(struct super_block *sb,
+		const unsigned char *p_cstring, const int len,
+		struct exfat_uni_name *uniname, int *p_lossy)
+{
+	if (EXFAT_SB(sb)->options.utf8)
+		return __exfat_nls_vfsname_to_utf16s(sb, p_cstring, len,
+				uniname, p_lossy);
+	return __exfat_nls_vfsname_to_uni16s(sb, p_cstring, len, uniname,
+			p_lossy);
+}
+
+static int exfat_load_upcase_table(struct super_block *sb,
+		sector_t sector, unsigned long long num_sectors,
+		unsigned int utbl_checksum)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int sect_size = sb->s_blocksize;
+	unsigned int i, index = 0, checksum = 0;
+	int ret;
+	unsigned char skip = false;
+	unsigned short *upcase_table;
+
+	upcase_table = kcalloc(UTBL_COUNT, sizeof(unsigned short), GFP_KERNEL);
+	if (!upcase_table)
+		return -ENOMEM;
+
+	sbi->vol_utbl = upcase_table;
+	num_sectors += sector;
+
+	while (sector < num_sectors) {
+		struct buffer_head *bh;
+
+		bh = sb_bread(sb, sector);
+		if (!bh) {
+			exfat_msg(sb, KERN_ERR,
+				"failed to read sector(0x%llx)\n", sector);
+			ret = -EIO;
+			goto free_table;
+		}
+		sector++;
+		for (i = 0; i < sect_size && index <= 0xFFFF; i += 2) {
+			unsigned short uni = get_unaligned_le16(bh->b_data + i);
+
+			checksum = ((checksum & 1) ? 0x80000000 : 0) +
+				(checksum >> 1) +
+				*(((unsigned char *)bh->b_data) + i);
+			checksum = ((checksum & 1) ? 0x80000000 : 0) +
+				(checksum >> 1) +
+				*(((unsigned char *)bh->b_data) + (i + 1));
+
+			if (skip) {
+				index += uni;
+				skip = false;
+			} else if (uni == index) {
+				index++;
+			} else if (uni == 0xFFFF) {
+				skip = true;
+			} else { /* uni != index , uni != 0xFFFF */
+				upcase_table[index] = uni;
+				index++;
+			}
+		}
+		brelse(bh);
+	}
+
+	if (index >= 0xFFFF && utbl_checksum == checksum)
+		return 0;
+
+	exfat_msg(sb, KERN_ERR,
+			"failed to load upcase table (idx : 0x%08x, chksum : 0x%08x, utbl_chksum : 0x%08x)\n",
+			index, checksum, utbl_checksum);
+	ret = -EINVAL;
+free_table:
+	exfat_free_upcase_table(sb);
+	return ret;
+}
+
+static int exfat_load_default_upcase_table(struct super_block *sb)
+{
+	int i, ret = -EIO;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned char skip = false;
+	unsigned short uni = 0, *upcase_table;
+	unsigned int index = 0;
+
+	upcase_table = kcalloc(UTBL_COUNT, sizeof(unsigned short), GFP_KERNEL);
+	if (!upcase_table)
+		return -ENOMEM;
+
+	sbi->vol_utbl = upcase_table;
+
+	for (i = 0; index <= 0xFFFF && i < EXFAT_NUM_UPCASE; i++) {
+		uni = uni_def_upcase[i];
+		if (skip) {
+			index += uni;
+			skip = false;
+		} else if (uni == index) {
+			index++;
+		} else if (uni == 0xFFFF) {
+			skip = true;
+		} else {
+			upcase_table[index] = uni;
+			index++;
+		}
+	}
+
+	if (index >= 0xFFFF)
+		return 0;
+
+	/* FATAL error: default upcase table has error */
+	exfat_free_upcase_table(sb);
+	return ret;
+}
+
+int exfat_create_upcase_table(struct super_block *sb)
+{
+	int i, ret;
+	unsigned int tbl_clu, type;
+	sector_t sector;
+	unsigned long long tbl_size, num_sectors;
+	unsigned char blksize_bits = sb->s_blocksize_bits;
+	struct exfat_chain clu;
+	struct exfat_dentry *ep;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct buffer_head *bh;
+
+	clu.dir = sbi->root_dir;
+	clu.flags = ALLOC_FAT_CHAIN;
+
+	while (clu.dir != EOF_CLUSTER) {
+		for (i = 0; i < sbi->dentries_per_clu; i++) {
+			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
+			if (!ep)
+				return -EIO;
+
+			type = exfat_get_entry_type(ep);
+			if (type == TYPE_UNUSED) {
+				brelse(bh);
+				break;
+			}
+
+			if (type != TYPE_UPCASE) {
+				brelse(bh);
+				continue;
+			}
+
+			tbl_clu  = le32_to_cpu(ep->upcase_start_clu);
+			tbl_size = le64_to_cpu(ep->upcase_size);
+
+			sector = exfat_cluster_to_sector(sbi, tbl_clu);
+			num_sectors = ((tbl_size - 1) >> blksize_bits) + 1;
+			ret = exfat_load_upcase_table(sb, sector, num_sectors,
+					le32_to_cpu(ep->upcase_checksum));
+
+			brelse(bh);
+			if (ret && ret != -EIO)
+				goto load_default;
+
+			/* load successfully */
+			return ret;
+		}
+
+		if (exfat_get_next_cluster(sb, &(clu.dir)))
+			return -EIO;
+	}
+
+load_default:
+	/* load default upcase table */
+	return exfat_load_default_upcase_table(sb);
+}
+
+void exfat_free_upcase_table(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	kfree(sbi->vol_utbl);
+	sbi->vol_utbl = NULL;
+}
-- 
2.17.1

[PATCH v6 11/13] exfat: add Kconfig and Makefile

[Namjae Jeon]

This adds the Kconfig and Makefile for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/Kconfig  | 21 +++++++++++++++++++++
 fs/exfat/Makefile |  8 ++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 fs/exfat/Kconfig
 create mode 100644 fs/exfat/Makefile

diff --git a/fs/exfat/Kconfig b/fs/exfat/Kconfig
new file mode 100644
index 000000000000..11d841a5f7f0
--- /dev/null
+++ b/fs/exfat/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+config EXFAT
+	tristate "exFAT filesystem support"
+	select NLS
+	help
+	  This allows you to mount devices formatted with the exFAT file system.
+	  exFAT is typically used on SD-Cards or USB sticks.
+
+	  To compile this as a module, choose M here: the module will be called
+	  exfat.
+
+config EXFAT_FS_DEFAULT_IOCHARSET
+	string "Default iocharset for exFAT"
+	default "utf8"
+	depends on EXFAT
+	help
+	  Set this to the default input/output character set you'd
+	  like exFAT to use. It should probably match the character set
+	  that most of your exFAT filesystems use, and can be overridden
+	  with the "iocharset" mount option for exFAT filesystems.
diff --git a/fs/exfat/Makefile b/fs/exfat/Makefile
new file mode 100644
index 000000000000..e9193346c80c
--- /dev/null
+++ b/fs/exfat/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Makefile for the linux exFAT filesystem support.
+#
+obj-$(CONFIG_EXFAT) += exfat.o
+
+exfat-y	:= inode.o namei.o dir.o super.o fatent.o cache.o nls.o misc.o \
+	   file.o balloc.o
-- 
2.17.1

[PATCH v6 12/13] exfat: add exfat in fs/Kconfig and fs/Makefile

[Namjae Jeon]

Add exfat in fs/Kconfig and fs/Makefile.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/Kconfig  | 3 ++-
 fs/Makefile | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 7b623e9fc1b0..5edd87eb5c13 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -139,9 +139,10 @@ endmenu
 endif # BLOCK
 
 if BLOCK
-menu "DOS/FAT/NT Filesystems"
+menu "DOS/FAT/EXFAT/NT Filesystems"
 
 source "fs/fat/Kconfig"
+source "fs/exfat/Kconfig"
 source "fs/ntfs/Kconfig"
 
 endmenu
diff --git a/fs/Makefile b/fs/Makefile
index 1148c555c4d3..4358dda56b1e 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_HUGETLBFS)		+= hugetlbfs/
 obj-$(CONFIG_CODA_FS)		+= coda/
 obj-$(CONFIG_MINIX_FS)		+= minix/
 obj-$(CONFIG_FAT_FS)		+= fat/
+obj-$(CONFIG_EXFAT)		+= exfat/
 obj-$(CONFIG_BFS_FS)		+= bfs/
 obj-$(CONFIG_ISO9660_FS)	+= isofs/
 obj-$(CONFIG_HFSPLUS_FS)	+= hfsplus/ # Before hfs to find wrapped HFS+
-- 
2.17.1

[PATCH v6 13/13] MAINTAINERS: add exfat filesystem

[Namjae Jeon]

Add myself and Sungjong Seo as exfat maintainer.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 8ecf4253d794..4523823ad5cc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6214,6 +6214,13 @@ F:	include/trace/events/mdio.h
 F:	include/uapi/linux/mdio.h
 F:	include/uapi/linux/mii.h
 
+EXFAT FILE SYSTEM
+M:	Namjae Jeon <namjae.jeon@samsung.com>
+M:	Sungjong Seo <sj1557.seo@samsung.com>
+L:	linux-fsdevel@vger.kernel.org
+S:	Maintained
+F:	fs/exfat/
+
 EXFAT FILE SYSTEM
 M:	Valdis Kletnieks <valdis.kletnieks@vt.edu>
 L:	linux-fsdevel@vger.kernel.org
-- 
2.17.1