[PATCH 09/25] staging: erofs: introduce xattr & acl support

Gao Xiang
2018-07-26T12:25:34Z

This implements xattr and acl functionalities.

Inline and shared xattrs are introduced for flexibility.
Specifically, if the same xattr occurs for many times
in a large number of inodes or the value of a xattr is so large
that it isn't suitable to be inlined, a shared xattr
kept in the xattr meta will be used instead.

Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
drivers/staging/erofs/Kconfig | 37 +++
drivers/staging/erofs/Makefile | 1 +
drivers/staging/erofs/inode.c | 33 ++-
drivers/staging/erofs/internal.h | 22 ++
drivers/staging/erofs/namei.c | 4 +
drivers/staging/erofs/super.c | 67 +++++
drivers/staging/erofs/xattr.c | 579 +++++++++++++++++++++++++++++++++++++++
drivers/staging/erofs/xattr.h | 93 +++++++
8 files changed, 835 insertions(+), 1 deletion(-)
create mode 100644 drivers/staging/erofs/xattr.c
create mode 100644 drivers/staging/erofs/xattr.h

diff --git a/drivers/staging/erofs/Kconfig b/drivers/staging/erofs/Kconfig
index 077430f..1a5ec1b 100644
--- a/drivers/staging/erofs/Kconfig
+++ b/drivers/staging/erofs/Kconfig
@@ -26,6 +26,43 @@ config EROFS_FS_DEBUG

For daily use, say N.

+config EROFS_FS_XATTR
+ bool "EROFS extended attributes"
+ depends on EROFS_FS
+ default y
+ help
+ Extended attributes are name:value pairs associated with inodes by
+ the kernel or by users (see the attr(5) manual page, or visit
+ <http://acl.bestbits.at/> for details).
+
+ If unsure, say N.
+
+config EROFS_FS_POSIX_ACL
+ bool "EROFS Access Control Lists"
+ depends on EROFS_FS_XATTR
+ select FS_POSIX_ACL
+ default y
+ help
+ Posix Access Control Lists (ACLs) support permissions for users and
+ groups beyond the owner/group/world scheme.
+
+ To learn more about Access Control Lists, visit the POSIX ACLs for
+ Linux website <http://acl.bestbits.at/>.
+
+ If you don't know what Access Control Lists are, say N.
+
+config EROFS_FS_SECURITY
+ bool "EROFS Security Labels"
+ depends on EROFS_FS_XATTR
+ help
+ Security labels provide an access control facility to support Linux
+ Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
+ Linux. This option enables an extended attribute handler for file
+ security labels in the erofs filesystem, so that it requires enabling
+ the extended attribute support in advance.
+
+ If you are not using a security module, say N.
+
config EROFS_FS_USE_VM_MAP_RAM
bool "EROFS VM_MAP_RAM Support"
depends on EROFS_FS
diff --git a/drivers/staging/erofs/Makefile b/drivers/staging/erofs/Makefile
index 31e909e..977b7e0 100644
--- a/drivers/staging/erofs/Makefile
+++ b/drivers/staging/erofs/Makefile
@@ -8,4 +8,5 @@ obj-$(CONFIG_EROFS_FS) += erofs.o
# staging requirement: to be self-contained in its own directory
ccflags-y += -I$(src)/include
erofs-objs := super.o inode.o data.o namei.o dir.o
+erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o

diff --git a/drivers/staging/erofs/inode.c b/drivers/staging/erofs/inode.c
index 74e65be..15ed919 100644
--- a/drivers/staging/erofs/inode.c
+++ b/drivers/staging/erofs/inode.c
@@ -10,7 +10,7 @@
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
-#include "internal.h"
+#include "xattr.h"

/* no locking */
static int read_inode(struct inode *inode, void *data)
@@ -152,15 +152,26 @@ static int fill_inode(struct inode *inode, int isdir)
if (!err) {
/* setup the new inode */
if (S_ISREG(inode->i_mode)) {
+#ifdef CONFIG_EROFS_FS_XATTR
+ if (vi->xattr_isize)
+ inode->i_op = &erofs_generic_xattr_iops;
+#endif
inode->i_fop = &generic_ro_fops;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op =
+#ifdef CONFIG_EROFS_FS_XATTR
+ vi->xattr_isize ? &erofs_dir_xattr_iops :
+#endif
&erofs_dir_iops;
inode->i_fop = &erofs_dir_fops;
} else if (S_ISLNK(inode->i_mode)) {
/* by default, page_get_link is used for symlink */
inode->i_op =
+#ifdef CONFIG_EROFS_FS_XATTR
+ &erofs_symlink_xattr_iops,
+#else
&page_symlink_inode_operations;
+#endif
inode_nohighmem(inode);
} else {
err = -EIO;
@@ -208,3 +219,23 @@ struct inode *erofs_iget(struct super_block *sb,
return inode;
}

+#ifdef CONFIG_EROFS_FS_XATTR
+const struct inode_operations erofs_generic_xattr_iops = {
+ .listxattr = erofs_listxattr,
+};
+#endif
+
+#ifdef CONFIG_EROFS_FS_XATTR
+const struct inode_operations erofs_symlink_xattr_iops = {
+ .get_link = page_get_link,
+ .listxattr = erofs_listxattr,
+};
+#endif
+
+#ifdef CONFIG_EROFS_FS_XATTR
+const struct inode_operations erofs_fast_symlink_xattr_iops = {
+ .get_link = simple_get_link,
+ .listxattr = erofs_listxattr,
+};
+#endif
+
diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index d0992d2..8a8caf0 100644
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -50,6 +50,9 @@
struct erofs_sb_info {
u32 blocks;
u32 meta_blkaddr;
+#ifdef CONFIG_EROFS_FS_XATTR
+ u32 xattr_blkaddr;
+#endif

/* inode slot unit size in bit shift */
unsigned char islotbits;
@@ -72,6 +75,10 @@ struct erofs_sb_info {
#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
#define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)

+/* Mount flags set via mount options or defaults */
+#define EROFS_MOUNT_XATTR_USER 0x00000010
+#define EROFS_MOUNT_POSIX_ACL 0x00000020
+
#define clear_opt(sbi, option) ((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
#define set_opt(sbi, option) ((sbi)->mount_opt |= EROFS_MOUNT_##option)
#define test_opt(sbi, option) ((sbi)->mount_opt & EROFS_MOUNT_##option)
@@ -237,17 +244,32 @@ int erofs_namei(struct inode *dir, struct qstr *name,
erofs_nid_t *nid, unsigned *d_type);

/* xattr.c */
+#ifdef CONFIG_EROFS_FS_XATTR
extern const struct xattr_handler *erofs_xattr_handlers[];
+#endif

/* symlink */
+#ifdef CONFIG_EROFS_FS_XATTR
+extern const struct inode_operations erofs_symlink_xattr_iops;
+extern const struct inode_operations erofs_fast_symlink_xattr_iops;
+#endif
+
static inline void set_inode_fast_symlink(struct inode *inode)
{
+#ifdef CONFIG_EROFS_FS_XATTR
+ inode->i_op = &erofs_fast_symlink_xattr_iops;
+#else
inode->i_op = &simple_symlink_inode_operations;
+#endif
}

static inline bool is_inode_fast_symlink(struct inode *inode)
{
+#ifdef CONFIG_EROFS_FS_XATTR
+ return inode->i_op == &erofs_fast_symlink_xattr_iops;
+#else
return inode->i_op == &simple_symlink_inode_operations;
+#endif
}

static inline void *erofs_vmap(struct page **pages, unsigned int count)
diff --git a/drivers/staging/erofs/namei.c b/drivers/staging/erofs/namei.c
index 39db643..989876b 100644
--- a/drivers/staging/erofs/namei.c
+++ b/drivers/staging/erofs/namei.c
@@ -11,6 +11,7 @@
* distribution for more details.
*/
#include "internal.h"
+#include "xattr.h"

/* based on the value of qn->len is accurate */
static inline int dirnamecmp(struct qstr *qn,
@@ -239,5 +240,8 @@ static struct dentry *erofs_lookup(struct inode *dir,

const struct inode_operations erofs_dir_xattr_iops = {
.lookup = erofs_lookup,
+#ifdef CONFIG_EROFS_FS_XATTR
+ .listxattr = erofs_listxattr,
+#endif
};

diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
index 98ae03d..4a8a266 100644
--- a/drivers/staging/erofs/super.c
+++ b/drivers/staging/erofs/super.c
@@ -14,6 +14,7 @@
#include <linux/buffer_head.h>
#include <linux/statfs.h>
#include <linux/parser.h>
+#include <linux/seq_file.h>
#include "internal.h"

static struct kmem_cache *erofs_inode_cachep __read_mostly;
@@ -107,6 +108,9 @@ static int superblock_read(struct super_block *sb)

sbi->blocks = le32_to_cpu(layout->blocks);
sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
+#ifdef CONFIG_EROFS_FS_XATTR
+ sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
+#endif
sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;

sbi->root_nid = le16_to_cpu(layout->root_nid);
@@ -127,13 +131,28 @@ static int superblock_read(struct super_block *sb)

static void default_options(struct erofs_sb_info *sbi)
{
+#ifdef CONFIG_EROFS_FS_XATTR
+ set_opt(sbi, XATTR_USER);
+#endif
+
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ set_opt(sbi, POSIX_ACL);
+#endif
}

enum {
+ Opt_user_xattr,
+ Opt_nouser_xattr,
+ Opt_acl,
+ Opt_noacl,
Opt_err
};

static match_table_t erofs_tokens = {
+ {Opt_user_xattr, "user_xattr"},
+ {Opt_nouser_xattr, "nouser_xattr"},
+ {Opt_acl, "acl"},
+ {Opt_noacl, "noacl"},
{Opt_err, NULL}
};

@@ -155,6 +174,36 @@ static int parse_options(struct super_block *sb, char *options)
token = match_token(p, erofs_tokens, args);

switch (token) {
+#ifdef CONFIG_EROFS_FS_XATTR
+ case Opt_user_xattr:
+ set_opt(EROFS_SB(sb), XATTR_USER);
+ break;
+ case Opt_nouser_xattr:
+ clear_opt(EROFS_SB(sb), XATTR_USER);
+ break;
+#else
+ case Opt_user_xattr:
+ infoln("user_xattr options not supported");
+ break;
+ case Opt_nouser_xattr:
+ infoln("nouser_xattr options not supported");
+ break;
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ case Opt_acl:
+ set_opt(EROFS_SB(sb), POSIX_ACL);
+ break;
+ case Opt_noacl:
+ clear_opt(EROFS_SB(sb), POSIX_ACL);
+ break;
+#else
+ case Opt_acl:
+ infoln("acl options not supported");
+ break;
+ case Opt_noacl:
+ infoln("noacl options not supported");
+ break;
+#endif
default:
errln("Unrecognized mount option \"%s\" "
"or missing value", p);
@@ -197,6 +246,10 @@ static int erofs_read_super(struct super_block *sb,

sb->s_op = &erofs_sops;

+#ifdef CONFIG_EROFS_FS_XATTR
+ sb->s_xattr = erofs_xattr_handlers;
+#endif
+
/* set erofs default mount options */
default_options(sbi);

@@ -386,6 +439,20 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)

static int erofs_show_options(struct seq_file *seq, struct dentry *root)
{
+ struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
+
+#ifdef CONFIG_EROFS_FS_XATTR
+ if (test_opt(sbi, XATTR_USER))
+ seq_puts(seq, ",user_xattr");
+ else
+ seq_puts(seq, ",nouser_xattr");
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ if (test_opt(sbi, POSIX_ACL))
+ seq_puts(seq, ",acl");
+ else
+ seq_puts(seq, ",noacl");
+#endif
return 0;
}

diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
new file mode 100644
index 0000000..b74b314
--- /dev/null
+++ b/drivers/staging/erofs/xattr.c
@@ -0,0 +1,579 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/drivers/staging/erofs/xattr.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+#include <linux/security.h>
+#include "xattr.h"
+
+struct xattr_iter {
+ struct super_block *sb;
+ struct page *page;
+ void *kaddr;
+
+ erofs_blk_t blkaddr;
+ unsigned ofs;
+};
+
+static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
+{
+ /* only init_inode_xattrs use non-atomic once */
+ if (unlikely(!atomic))
+ kunmap(it->page);
+ else
+ kunmap_atomic(it->kaddr);
+ unlock_page(it->page);
+ put_page(it->page);
+}
+
+static void init_inode_xattrs(struct inode *inode)
+{
+ struct xattr_iter it;
+ unsigned i;
+ struct erofs_xattr_ibody_header *ih;
+ struct erofs_sb_info *sbi;
+ struct erofs_vnode *vi;
+ bool atomic_map;
+
+ if (likely(inode_has_inited_xattr(inode)))
+ return;
+
+ vi = EROFS_V(inode);
+ BUG_ON(!vi->xattr_isize);
+
+ sbi = EROFS_I_SB(inode);
+ it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
+ it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
+
+ it.page = erofs_get_inline_page(inode, it.blkaddr);
+ BUG_ON(IS_ERR(it.page));
+
+ /* read in shared xattr array (non-atomic, see kmalloc below) */
+ it.kaddr = kmap(it.page);
+ atomic_map = false;
+
+ ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
+
+ vi->xattr_shared_count = ih->h_shared_count;
+ vi->xattr_shared_xattrs = (unsigned *)kmalloc_array(
+ vi->xattr_shared_count, sizeof(unsigned),
+ GFP_KERNEL | __GFP_NOFAIL);
+
+ /* let's skip ibody header */
+ it.ofs += sizeof(struct erofs_xattr_ibody_header);
+
+ for (i = 0; i < vi->xattr_shared_count; ++i) {
+ if (unlikely(it.ofs >= EROFS_BLKSIZ)) {
+ /* cannot be unaligned */
+ BUG_ON(it.ofs != EROFS_BLKSIZ);
+ xattr_iter_end(&it, atomic_map);
+
+ it.page = erofs_get_meta_page(inode->i_sb,
+ ++it.blkaddr, S_ISDIR(inode->i_mode));
+ BUG_ON(IS_ERR(it.page));
+
+ it.kaddr = kmap_atomic(it.page);
+ atomic_map = true;
+ it.ofs = 0;
+ }
+ vi->xattr_shared_xattrs[i] =
+ le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
+ it.ofs += sizeof(__le32);
+ }
+ xattr_iter_end(&it, atomic_map);
+
+ inode_set_inited_xattr(inode);
+}
+
+struct xattr_iter_handlers {
+ int (*entry)(struct xattr_iter *, struct erofs_xattr_entry *);
+ int (*name)(struct xattr_iter *, unsigned, char *, unsigned);
+ int (*alloc_buffer)(struct xattr_iter *, unsigned);
+ void (*value)(struct xattr_iter *, unsigned, char *, unsigned);
+};
+
+static void xattr_iter_fixup(struct xattr_iter *it)
+{
+ if (unlikely(it->ofs >= EROFS_BLKSIZ)) {
+ xattr_iter_end(it, true);
+
+ it->blkaddr += erofs_blknr(it->ofs);
+ it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
+ BUG_ON(IS_ERR(it->page));
+
+ it->kaddr = kmap_atomic(it->page);
+ it->ofs = erofs_blkoff(it->ofs);
+ }
+}
+
+static int inline_xattr_iter_begin(struct xattr_iter *it,
+ struct inode *inode)
+{
+ struct erofs_vnode *const vi = EROFS_V(inode);
+ struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
+ unsigned xattr_header_sz, inline_xattr_ofs;
+
+ xattr_header_sz = inlinexattr_header_size(inode);
+ if (unlikely(xattr_header_sz >= vi->xattr_isize)) {
+ BUG_ON(xattr_header_sz > vi->xattr_isize);
+ return -ENOATTR;
+ }
+
+ inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
+
+ it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
+ it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
+
+ it->page = erofs_get_inline_page(inode, it->blkaddr);
+ BUG_ON(IS_ERR(it->page));
+ it->kaddr = kmap_atomic(it->page);
+
+ return vi->xattr_isize - xattr_header_sz;
+}
+
+static int xattr_foreach(struct xattr_iter *it,
+ struct xattr_iter_handlers *op, unsigned *tlimit)
+{
+ struct erofs_xattr_entry entry;
+ unsigned value_sz, processed, slice;
+ int err;
+
+ /* 0. fixup blkaddr, ofs, ipage */
+ xattr_iter_fixup(it);
+
+ /*
+ * 1. read xattr entry to the memory,
+ * since we do EROFS_XATTR_ALIGN
+ * therefore entry should be in the page
+ */
+ entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
+ if (tlimit != NULL) {
+ unsigned entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry);
+
+ BUG_ON(*tlimit < entry_sz);
+ *tlimit -= entry_sz;
+ }
+
+ it->ofs += sizeof(struct erofs_xattr_entry);
+ value_sz = le16_to_cpu(entry.e_value_size);
+
+ /* handle entry */
+ err = op->entry(it, &entry);
+ if (err) {
+ it->ofs += entry.e_name_len + value_sz;
+ goto out;
+ }
+
+ /* 2. handle xattr name (ofs will finally be at the end of name) */
+ processed = 0;
+
+ while (processed < entry.e_name_len) {
+ if (it->ofs >= EROFS_BLKSIZ) {
+ BUG_ON(it->ofs > EROFS_BLKSIZ);
+
+ xattr_iter_fixup(it);
+ it->ofs = 0;
+ }
+
+ slice = min_t(unsigned, PAGE_SIZE - it->ofs,
+ entry.e_name_len - processed);
+
+ /* handle name */
+ err = op->name(it, processed, it->kaddr + it->ofs, slice);
+ if (err) {
+ it->ofs += entry.e_name_len - processed + value_sz;
+ goto out;
+ }
+
+ it->ofs += slice;
+ processed += slice;
+ }
+
+ /* 3. handle xattr value */
+ processed = 0;
+
+ if (op->alloc_buffer != NULL) {
+ err = op->alloc_buffer(it, value_sz);
+ if (err) {
+ it->ofs += value_sz;
+ goto out;
+ }
+ }
+
+ while (processed < value_sz) {
+ if (it->ofs >= EROFS_BLKSIZ) {
+ BUG_ON(it->ofs > EROFS_BLKSIZ);
+ xattr_iter_fixup(it);
+ it->ofs = 0;
+ }
+
+ slice = min_t(unsigned, PAGE_SIZE - it->ofs,
+ value_sz - processed);
+ op->value(it, processed, it->kaddr + it->ofs, slice);
+ it->ofs += slice;
+ processed += slice;
+ }
+
+out:
+ /* we assume that ofs is aligned with 4 bytes */
+ it->ofs = EROFS_XATTR_ALIGN(it->ofs);
+ return err;
+}
+
+struct getxattr_iter {
+ struct xattr_iter it;
+
+ char *buffer;
+ int buffer_size, index;
+ struct qstr name;
+};
+
+static int xattr_entrymatch(struct xattr_iter *_it,
+ struct erofs_xattr_entry *entry)
+{
+ struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+
+ return (it->index != entry->e_name_index ||
+ it->name.len != entry->e_name_len) ? -ENOATTR : 0;
+}
+
+static int xattr_namematch(struct xattr_iter *_it,
+ unsigned processed, char *buf, unsigned len)
+{
+ struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+
+ return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
+}
+
+static int xattr_checkbuffer(struct xattr_iter *_it,
+ unsigned value_sz)
+{
+ struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+ int err = it->buffer_size < value_sz ? -ERANGE : 0;
+
+ it->buffer_size = value_sz;
+ return it->buffer == NULL ? 1 : err;
+}
+
+static void xattr_copyvalue(struct xattr_iter *_it,
+ unsigned processed, char *buf, unsigned len)
+{
+ struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+
+ memcpy(it->buffer + processed, buf, len);
+}
+
+static struct xattr_iter_handlers find_xattr_handlers = {
+ .entry = xattr_entrymatch,
+ .name = xattr_namematch,
+ .alloc_buffer = xattr_checkbuffer,
+ .value = xattr_copyvalue
+};
+
+static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
+{
+ int ret;
+ unsigned remaining;
+
+ ret = inline_xattr_iter_begin(&it->it, inode);
+ if (ret < 0)
+ return ret;
+
+ remaining = ret;
+ while (remaining) {
+ if ((ret = xattr_foreach(&it->it,
+ &find_xattr_handlers, &remaining)) >= 0)
+ break;
+ }
+ xattr_iter_end(&it->it, true);
+
+ return ret < 0 ? ret : it->buffer_size;
+}
+
+static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
+{
+ struct erofs_vnode *const vi = EROFS_V(inode);
+ struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
+ unsigned i;
+ int ret = -ENOATTR;
+
+ for (i = 0; i < vi->xattr_shared_count; ++i) {
+ erofs_blk_t blkaddr =
+ xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
+
+ it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
+
+ if (!i || blkaddr != it->it.blkaddr) {
+ if (i)
+ xattr_iter_end(&it->it, true);
+
+ it->it.page = erofs_get_meta_page(inode->i_sb,
+ blkaddr, false);
+ BUG_ON(IS_ERR(it->it.page));
+ it->it.kaddr = kmap_atomic(it->it.page);
+ it->it.blkaddr = blkaddr;
+ }
+
+ if ((ret = xattr_foreach(&it->it,
+ &find_xattr_handlers, NULL)) >= 0)
+ break;
+ }
+ if (vi->xattr_shared_count)
+ xattr_iter_end(&it->it, true);
+
+ return ret < 0 ? ret : it->buffer_size;
+}
+
+static bool erofs_xattr_user_list(struct dentry *dentry)
+{
+ return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER);
+}
+
+static bool erofs_xattr_trusted_list(struct dentry *dentry)
+{
+ return capable(CAP_SYS_ADMIN);
+}
+
+int erofs_getxattr(struct inode *inode, int index,
+ const char *name,
+ void *buffer, size_t buffer_size)
+{
+ int ret;
+ struct getxattr_iter it;
+
+ if (unlikely(name == NULL))
+ return -EINVAL;
+
+ init_inode_xattrs(inode);
+
+ it.index = index;
+
+ it.name.len = strlen(name);
+ if (it.name.len > EROFS_NAME_LEN)
+ return -ERANGE;
+ it.name.name = name;
+
+ it.buffer = buffer;
+ it.buffer_size = buffer_size;
+
+ it.it.sb = inode->i_sb;
+ ret = inline_getxattr(inode, &it);
+ if (ret == -ENOATTR)
+ ret = shared_getxattr(inode, &it);
+ return ret;
+}
+
+static int erofs_xattr_generic_get(const struct xattr_handler *handler,
+ struct dentry *unused, struct inode *inode,
+ const char *name, void *buffer, size_t size)
+{
+ struct erofs_vnode *const vi = EROFS_V(inode);
+ struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
+
+ switch (handler->flags) {
+ case EROFS_XATTR_INDEX_USER:
+ if (!test_opt(sbi, XATTR_USER))
+ return -EOPNOTSUPP;
+ break;
+ case EROFS_XATTR_INDEX_TRUSTED:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ break;
+ case EROFS_XATTR_INDEX_SECURITY:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (!vi->xattr_isize)
+ return -ENOATTR;
+
+ return erofs_getxattr(inode, handler->flags, name, buffer, size);
+}
+
+const struct xattr_handler erofs_xattr_user_handler = {
+ .prefix = XATTR_USER_PREFIX,
+ .flags = EROFS_XATTR_INDEX_USER,
+ .list = erofs_xattr_user_list,
+ .get = erofs_xattr_generic_get,
+};
+
+const struct xattr_handler erofs_xattr_trusted_handler = {
+ .prefix = XATTR_TRUSTED_PREFIX,
+ .flags = EROFS_XATTR_INDEX_TRUSTED,
+ .list = erofs_xattr_trusted_list,
+ .get = erofs_xattr_generic_get,
+};
+
+#ifdef CONFIG_EROFS_FS_SECURITY
+const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
+ .prefix = XATTR_SECURITY_PREFIX,
+ .flags = EROFS_XATTR_INDEX_SECURITY,
+ .get = erofs_xattr_generic_get,
+};
+#endif
+
+#ifdef CONFIG_EROFS_FS_XATTR
+const struct xattr_handler *erofs_xattr_handlers[] = {
+ &erofs_xattr_user_handler,
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ &posix_acl_access_xattr_handler,
+ &posix_acl_default_xattr_handler,
+#endif
+ &erofs_xattr_trusted_handler,
+#ifdef CONFIG_EROFS_FS_SECURITY
+ &erofs_xattr_security_handler,
+#endif
+ NULL,
+};
+#endif
+
+struct listxattr_iter {
+ struct xattr_iter it;
+
+ struct dentry *dentry;
+ char *buffer;
+ int buffer_size, buffer_ofs;
+};
+
+static int xattr_entrylist(struct xattr_iter *_it,
+ struct erofs_xattr_entry *entry)
+{
+ struct listxattr_iter *it =
+ container_of(_it, struct listxattr_iter, it);
+ unsigned prefix_len;
+ const char *prefix;
+
+ const struct xattr_handler *h =
+ erofs_xattr_handler(entry->e_name_index);
+
+ if (h == NULL || (h->list != NULL && !h->list(it->dentry)))
+ return 1;
+
+ /* Note that at least one of 'prefix' and 'name' should be non-NULL */
+ prefix = h->prefix != NULL ? h->prefix : h->name;
+ prefix_len = strlen(prefix);
+
+ if (it->buffer == NULL) {
+ it->buffer_ofs += prefix_len + entry->e_name_len + 1;
+ return 1;
+ }
+
+ if (it->buffer_ofs + prefix_len
+ + entry->e_name_len + 1 > it->buffer_size)
+ return -ERANGE;
+
+ memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
+ it->buffer_ofs += prefix_len;
+ return 0;
+}
+
+static int xattr_namelist(struct xattr_iter *_it,
+ unsigned processed, char *buf, unsigned len)
+{
+ struct listxattr_iter *it =
+ container_of(_it, struct listxattr_iter, it);
+
+ memcpy(it->buffer + it->buffer_ofs, buf, len);
+ it->buffer_ofs += len;
+ return 0;
+}
+
+static int xattr_skipvalue(struct xattr_iter *_it,
+ unsigned value_sz)
+{
+ struct listxattr_iter *it =
+ container_of(_it, struct listxattr_iter, it);
+
+ it->buffer[it->buffer_ofs++] = '\0';
+ return 1;
+}
+
+static struct xattr_iter_handlers list_xattr_handlers = {
+ .entry = xattr_entrylist,
+ .name = xattr_namelist,
+ .alloc_buffer = xattr_skipvalue,
+ .value = NULL
+};
+
+static int inline_listxattr(struct listxattr_iter *it)
+{
+ int ret;
+ unsigned remaining;
+
+ ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
+ if (ret < 0)
+ return ret;
+
+ remaining = ret;
+ while (remaining) {
+ if ((ret = xattr_foreach(&it->it,
+ &list_xattr_handlers, &remaining)) < 0)
+ break;
+ }
+ xattr_iter_end(&it->it, true);
+ return ret < 0 ? ret : it->buffer_ofs;
+}
+
+static int shared_listxattr(struct listxattr_iter *it)
+{
+ struct inode *const inode = d_inode(it->dentry);
+ struct erofs_vnode *const vi = EROFS_V(inode);
+ struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
+ unsigned i;
+ int ret = 0;
+
+ for (i = 0; i < vi->xattr_shared_count; ++i) {
+ erofs_blk_t blkaddr =
+ xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
+
+ it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
+ if (!i || blkaddr != it->it.blkaddr) {
+ if (i)
+ xattr_iter_end(&it->it, true);
+
+ it->it.page = erofs_get_meta_page(inode->i_sb,
+ blkaddr, false);
+ BUG_ON(IS_ERR(it->it.page));
+ it->it.kaddr = kmap_atomic(it->it.page);
+ it->it.blkaddr = blkaddr;
+ }
+
+ if ((ret = xattr_foreach(&it->it,
+ &list_xattr_handlers, NULL)) < 0)
+ break;
+ }
+ if (vi->xattr_shared_count)
+ xattr_iter_end(&it->it, true);
+
+ return ret < 0 ? ret : it->buffer_ofs;
+}
+
+ssize_t erofs_listxattr(struct dentry *dentry,
+ char *buffer, size_t buffer_size)
+{
+ int ret;
+ struct listxattr_iter it;
+
+ init_inode_xattrs(d_inode(dentry));
+
+ it.dentry = dentry;
+ it.buffer = buffer;
+ it.buffer_size = buffer_size;
+ it.buffer_ofs = 0;
+
+ it.it.sb = dentry->d_sb;
+
+ ret = inline_listxattr(&it);
+ if (ret < 0 && ret != -ENOATTR)
+ return ret;
+ return shared_listxattr(&it);
+}
+
diff --git a/drivers/staging/erofs/xattr.h b/drivers/staging/erofs/xattr.h
new file mode 100644
index 0000000..0c73792
--- /dev/null
+++ b/drivers/staging/erofs/xattr.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * linux/drivers/staging/erofs/xattr.h
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+#ifndef __EROFS_XATTR_H
+#define __EROFS_XATTR_H
+
+#include "internal.h"
+#include <linux/posix_acl_xattr.h>
+#include <linux/xattr.h>
+
+/* Attribute not found */
+#define ENOATTR ENODATA
+
+static inline unsigned inlinexattr_header_size(struct inode *inode)
+{
+ return sizeof(struct erofs_xattr_ibody_header)
+ + sizeof(u32) * EROFS_V(inode)->xattr_shared_count;
+}
+
+static inline erofs_blk_t
+xattrblock_addr(struct erofs_sb_info *sbi, unsigned xattr_id)
+{
+#ifdef CONFIG_EROFS_FS_XATTR
+ return sbi->xattr_blkaddr +
+ xattr_id * sizeof(__u32) / EROFS_BLKSIZ;
+#else
+ return 0;
+#endif
+}
+
+static inline unsigned
+xattrblock_offset(struct erofs_sb_info *sbi, unsigned xattr_id)
+{
+ return (xattr_id * sizeof(__u32)) % EROFS_BLKSIZ;
+}
+
+extern const struct xattr_handler erofs_xattr_user_handler;
+extern const struct xattr_handler erofs_xattr_trusted_handler;
+#ifdef CONFIG_EROFS_FS_SECURITY
+extern const struct xattr_handler erofs_xattr_security_handler;
+#endif
+
+static inline const struct xattr_handler *erofs_xattr_handler(unsigned index)
+{
+static const struct xattr_handler *xattr_handler_map[] = {
+ [EROFS_XATTR_INDEX_USER] = &erofs_xattr_user_handler,
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ [EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
+ [EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] =
+ &posix_acl_default_xattr_handler,
+#endif
+ [EROFS_XATTR_INDEX_TRUSTED] = &erofs_xattr_trusted_handler,
+#ifdef CONFIG_EROFS_FS_SECURITY
+ [EROFS_XATTR_INDEX_SECURITY] = &erofs_xattr_security_handler,
+#endif
+};
+ return index && index < ARRAY_SIZE(xattr_handler_map) ?
+ xattr_handler_map[index] : NULL;
+}
+
+#ifdef CONFIG_EROFS_FS_XATTR
+
+extern const struct inode_operations erofs_generic_xattr_iops;
+extern const struct inode_operations erofs_dir_xattr_iops;
+
+int erofs_getxattr(struct inode *, int, const char *, void *, size_t);
+ssize_t erofs_listxattr(struct dentry *, char *, size_t);
+#else
+static int __maybe_unused erofs_getxattr(struct inode *inode, int index,
+ const char *name,
+ void *buffer, size_t buffer_size)
+{
+ return -ENOTSUPP;
+}
+
+static ssize_t __maybe_unused erofs_listxattr(struct dentry *dentry,
+ char *buffer, size_t buffer_size)
+{
+ return -ENOTSUPP;
+}
+#endif
+
+#endif
+
--
1.9.1