* [PATCH 1/3] fs: rename fs_types.h to fs_dirent.h
2025-11-04 14:46 [PATCH 0/3] fs: start to split up fs.h Christian Brauner
@ 2025-11-04 14:46 ` Christian Brauner
2025-11-04 14:46 ` [PATCH 2/3] fs: add fs_super_types header Christian Brauner
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Christian Brauner @ 2025-11-04 14:46 UTC (permalink / raw)
To: linux-fsdevel; +Cc: Alexander Viro, Jan Kara, linux-kernel, Christian Brauner
We will split out a bunch of types into a separate header.
So free up the appropriate name for it.
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
| 2 +-
| 2 +-
| 2 +-
| 11 +++++++----
4 files changed, 10 insertions(+), 7 deletions(-)
--git a/fs/Makefile b/fs/Makefile
index e3523ab2e587..a04274a3c854 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -14,7 +14,7 @@ obj-y := open.o read_write.o file_table.o super.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o splice.o sync.o utimes.o d_path.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
- fs_types.o fs_context.o fs_parser.o fsopen.o init.o \
+ fs_dirent.o fs_context.o fs_parser.o fsopen.o init.o \
kernel_read_file.o mnt_idmapping.o remap_range.o pidfs.o \
file_attr.o
--git a/fs/fs_types.c b/fs/fs_dirent.c
similarity index 98%
rename from fs/fs_types.c
rename to fs/fs_dirent.c
index 78365e5dc08c..e5e08f213816 100644
--- a/fs/fs_types.c
+++ b/fs/fs_dirent.c
@@ -1,5 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
-#include <linux/fs.h>
+#include <linux/fs_dirent.h>
#include <linux/export.h>
/*
--git a/include/linux/fs.h b/include/linux/fs.h
index c895146c1444..3c971ddace41 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -37,7 +37,7 @@
#include <linux/uuid.h>
#include <linux/errseq.h>
#include <linux/ioprio.h>
-#include <linux/fs_types.h>
+#include <linux/fs_dirent.h>
#include <linux/build_bug.h>
#include <linux/stddef.h>
#include <linux/mount.h>
--git a/include/linux/fs_types.h b/include/linux/fs_dirent.h
similarity index 92%
rename from include/linux/fs_types.h
rename to include/linux/fs_dirent.h
index 54816791196f..92f75c5bac19 100644
--- a/include/linux/fs_types.h
+++ b/include/linux/fs_dirent.h
@@ -1,6 +1,9 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_FS_TYPES_H
-#define _LINUX_FS_TYPES_H
+#ifndef _LINUX_FS_DIRENT_H
+#define _LINUX_FS_DIRENT_H
+
+#include <linux/stat.h>
+#include <linux/types.h>
/*
* This is a header for the common implementation of dirent
@@ -66,10 +69,10 @@
/*
* declarations for helper functions, accompanying implementation
- * is in fs/fs_types.c
+ * is in fs/fs_dirent.c
*/
extern unsigned char fs_ftype_to_dtype(unsigned int filetype);
extern unsigned char fs_umode_to_ftype(umode_t mode);
extern unsigned char fs_umode_to_dtype(umode_t mode);
-#endif
+#endif /* _LINUX_FS_DIRENT_H */
--
2.47.3
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 2/3] fs: add fs_super_types header
2025-11-04 14:46 [PATCH 0/3] fs: start to split up fs.h Christian Brauner
2025-11-04 14:46 ` [PATCH 1/3] fs: rename fs_types.h to fs_dirent.h Christian Brauner
@ 2025-11-04 14:46 ` Christian Brauner
2025-11-04 14:46 ` [PATCH 3/3] fs: add fs_super.h header Christian Brauner
2025-11-05 12:55 ` [PATCH 0/3] fs: start to split up fs.h Christoph Hellwig
3 siblings, 0 replies; 7+ messages in thread
From: Christian Brauner @ 2025-11-04 14:46 UTC (permalink / raw)
To: linux-fsdevel; +Cc: Alexander Viro, Jan Kara, linux-kernel, Christian Brauner
Split out super block associated structures into a separate header.
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
| 308 +------------------------------------
| 335 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 336 insertions(+), 307 deletions(-)
--git a/include/linux/fs.h b/include/linux/fs.h
index 3c971ddace41..17fa9b64354b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2,6 +2,7 @@
#ifndef _LINUX_FS_H
#define _LINUX_FS_H
+#include <linux/fs_super_types.h>
#include <linux/vfsdebug.h>
#include <linux/linkage.h>
#include <linux/wait_bit.h>
@@ -11,7 +12,6 @@
#include <linux/stat.h>
#include <linux/cache.h>
#include <linux/list.h>
-#include <linux/list_lru.h>
#include <linux/llist.h>
#include <linux/radix-tree.h>
#include <linux/xarray.h>
@@ -37,7 +37,6 @@
#include <linux/uuid.h>
#include <linux/errseq.h>
#include <linux/ioprio.h>
-#include <linux/fs_dirent.h>
#include <linux/build_bug.h>
#include <linux/stddef.h>
#include <linux/mount.h>
@@ -52,11 +51,9 @@
#include <asm/byteorder.h>
#include <uapi/linux/fs.h>
-struct backing_dev_info;
struct bdi_writeback;
struct bio;
struct io_comp_batch;
-struct export_operations;
struct fiemap_extent_info;
struct hd_geometry;
struct iovec;
@@ -70,12 +67,8 @@ struct vfsmount;
struct cred;
struct swap_info_struct;
struct seq_file;
-struct workqueue_struct;
struct iov_iter;
-struct fscrypt_operations;
-struct fsverity_operations;
struct fsnotify_mark_connector;
-struct fsnotify_sb_info;
struct fs_context;
struct fs_parameter_spec;
struct file_kattr;
@@ -298,11 +291,6 @@ struct iattr {
struct file *ia_file;
};
-/*
- * Includes for diskquotas.
- */
-#include <linux/quota.h>
-
/*
* Maximum number of layers of fs stack. Needs to be limited to
* prevent kernel stack overflow
@@ -1347,49 +1335,6 @@ extern void f_delown(struct file *filp);
extern pid_t f_getown(struct file *filp);
extern int send_sigurg(struct file *file);
-/*
- * sb->s_flags. Note that these mirror the equivalent MS_* flags where
- * represented in both.
- */
-#define SB_RDONLY BIT(0) /* Mount read-only */
-#define SB_NOSUID BIT(1) /* Ignore suid and sgid bits */
-#define SB_NODEV BIT(2) /* Disallow access to device special files */
-#define SB_NOEXEC BIT(3) /* Disallow program execution */
-#define SB_SYNCHRONOUS BIT(4) /* Writes are synced at once */
-#define SB_MANDLOCK BIT(6) /* Allow mandatory locks on an FS */
-#define SB_DIRSYNC BIT(7) /* Directory modifications are synchronous */
-#define SB_NOATIME BIT(10) /* Do not update access times. */
-#define SB_NODIRATIME BIT(11) /* Do not update directory access times */
-#define SB_SILENT BIT(15)
-#define SB_POSIXACL BIT(16) /* Supports POSIX ACLs */
-#define SB_INLINECRYPT BIT(17) /* Use blk-crypto for encrypted files */
-#define SB_KERNMOUNT BIT(22) /* this is a kern_mount call */
-#define SB_I_VERSION BIT(23) /* Update inode I_version field */
-#define SB_LAZYTIME BIT(25) /* Update the on-disk [acm]times lazily */
-
-/* These sb flags are internal to the kernel */
-#define SB_DEAD BIT(21)
-#define SB_DYING BIT(24)
-#define SB_FORCE BIT(27)
-#define SB_NOSEC BIT(28)
-#define SB_BORN BIT(29)
-#define SB_ACTIVE BIT(30)
-#define SB_NOUSER BIT(31)
-
-/* These flags relate to encoding and casefolding */
-#define SB_ENC_STRICT_MODE_FL (1 << 0)
-#define SB_ENC_NO_COMPAT_FALLBACK_FL (1 << 1)
-
-#define sb_has_strict_encoding(sb) \
- (sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL)
-
-#if IS_ENABLED(CONFIG_UNICODE)
-#define sb_no_casefold_compat_fallback(sb) \
- (sb->s_encoding_flags & SB_ENC_NO_COMPAT_FALLBACK_FL)
-#else
-#define sb_no_casefold_compat_fallback(sb) (1)
-#endif
-
/*
* Umount options
*/
@@ -1400,191 +1345,6 @@ extern int send_sigurg(struct file *file);
#define UMOUNT_NOFOLLOW 0x00000008 /* Don't follow symlink on umount */
#define UMOUNT_UNUSED 0x80000000 /* Flag guaranteed to be unused */
-/* sb->s_iflags */
-#define SB_I_CGROUPWB 0x00000001 /* cgroup-aware writeback enabled */
-#define SB_I_NOEXEC 0x00000002 /* Ignore executables on this fs */
-#define SB_I_NODEV 0x00000004 /* Ignore devices on this fs */
-#define SB_I_STABLE_WRITES 0x00000008 /* don't modify blks until WB is done */
-
-/* sb->s_iflags to limit user namespace mounts */
-#define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */
-#define SB_I_IMA_UNVERIFIABLE_SIGNATURE 0x00000020
-#define SB_I_UNTRUSTED_MOUNTER 0x00000040
-#define SB_I_EVM_HMAC_UNSUPPORTED 0x00000080
-
-#define SB_I_SKIP_SYNC 0x00000100 /* Skip superblock at global sync */
-#define SB_I_PERSB_BDI 0x00000200 /* has a per-sb bdi */
-#define SB_I_TS_EXPIRY_WARNED 0x00000400 /* warned about timestamp range expiry */
-#define SB_I_RETIRED 0x00000800 /* superblock shouldn't be reused */
-#define SB_I_NOUMASK 0x00001000 /* VFS does not apply umask */
-#define SB_I_NOIDMAP 0x00002000 /* No idmapped mounts on this superblock */
-#define SB_I_ALLOW_HSM 0x00004000 /* Allow HSM events on this superblock */
-
-/* Possible states of 'frozen' field */
-enum {
- SB_UNFROZEN = 0, /* FS is unfrozen */
- SB_FREEZE_WRITE = 1, /* Writes, dir ops, ioctls frozen */
- SB_FREEZE_PAGEFAULT = 2, /* Page faults stopped as well */
- SB_FREEZE_FS = 3, /* For internal FS use (e.g. to stop
- * internal threads if needed) */
- SB_FREEZE_COMPLETE = 4, /* ->freeze_fs finished successfully */
-};
-
-#define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
-
-struct sb_writers {
- unsigned short frozen; /* Is sb frozen? */
- int freeze_kcount; /* How many kernel freeze requests? */
- int freeze_ucount; /* How many userspace freeze requests? */
- const void *freeze_owner; /* Owner of the freeze */
- struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS];
-};
-
-struct mount;
-
-struct super_block {
- struct list_head s_list; /* Keep this first */
- dev_t s_dev; /* search index; _not_ kdev_t */
- unsigned char s_blocksize_bits;
- unsigned long s_blocksize;
- loff_t s_maxbytes; /* Max file size */
- struct file_system_type *s_type;
- const struct super_operations *s_op;
- const struct dquot_operations *dq_op;
- const struct quotactl_ops *s_qcop;
- const struct export_operations *s_export_op;
- unsigned long s_flags;
- unsigned long s_iflags; /* internal SB_I_* flags */
- unsigned long s_magic;
- struct dentry *s_root;
- struct rw_semaphore s_umount;
- int s_count;
- atomic_t s_active;
-#ifdef CONFIG_SECURITY
- void *s_security;
-#endif
- const struct xattr_handler * const *s_xattr;
-#ifdef CONFIG_FS_ENCRYPTION
- const struct fscrypt_operations *s_cop;
- struct fscrypt_keyring *s_master_keys; /* master crypto keys in use */
-#endif
-#ifdef CONFIG_FS_VERITY
- const struct fsverity_operations *s_vop;
-#endif
-#if IS_ENABLED(CONFIG_UNICODE)
- struct unicode_map *s_encoding;
- __u16 s_encoding_flags;
-#endif
- struct hlist_bl_head s_roots; /* alternate root dentries for NFS */
- struct mount *s_mounts; /* list of mounts; _not_ for fs use */
- struct block_device *s_bdev; /* can go away once we use an accessor for @s_bdev_file */
- struct file *s_bdev_file;
- struct backing_dev_info *s_bdi;
- struct mtd_info *s_mtd;
- struct hlist_node s_instances;
- unsigned int s_quota_types; /* Bitmask of supported quota types */
- struct quota_info s_dquot; /* Diskquota specific options */
-
- struct sb_writers s_writers;
-
- /*
- * Keep s_fs_info, s_time_gran, s_fsnotify_mask, and
- * s_fsnotify_info together for cache efficiency. They are frequently
- * accessed and rarely modified.
- */
- void *s_fs_info; /* Filesystem private info */
-
- /* Granularity of c/m/atime in ns (cannot be worse than a second) */
- u32 s_time_gran;
- /* Time limits for c/m/atime in seconds */
- time64_t s_time_min;
- time64_t s_time_max;
-#ifdef CONFIG_FSNOTIFY
- u32 s_fsnotify_mask;
- struct fsnotify_sb_info *s_fsnotify_info;
-#endif
-
- /*
- * q: why are s_id and s_sysfs_name not the same? both are human
- * readable strings that identify the filesystem
- * a: s_id is allowed to change at runtime; it's used in log messages,
- * and we want to when a device starts out as single device (s_id is dev
- * name) but then a device is hot added and we have to switch to
- * identifying it by UUID
- * but s_sysfs_name is a handle for programmatic access, and can't
- * change at runtime
- */
- char s_id[32]; /* Informational name */
- uuid_t s_uuid; /* UUID */
- u8 s_uuid_len; /* Default 16, possibly smaller for weird filesystems */
-
- /* if set, fs shows up under sysfs at /sys/fs/$FSTYP/s_sysfs_name */
- char s_sysfs_name[UUID_STRING_LEN + 1];
-
- unsigned int s_max_links;
- unsigned int s_d_flags; /* default d_flags for dentries */
-
- /*
- * The next field is for VFS *only*. No filesystems have any business
- * even looking at it. You had been warned.
- */
- struct mutex s_vfs_rename_mutex; /* Kludge */
-
- /*
- * Filesystem subtype. If non-empty the filesystem type field
- * in /proc/mounts will be "type.subtype"
- */
- const char *s_subtype;
-
- const struct dentry_operations *__s_d_op; /* default d_op for dentries */
-
- struct shrinker *s_shrink; /* per-sb shrinker handle */
-
- /* Number of inodes with nlink == 0 but still referenced */
- atomic_long_t s_remove_count;
-
- /* Read-only state of the superblock is being changed */
- int s_readonly_remount;
-
- /* per-sb errseq_t for reporting writeback errors via syncfs */
- errseq_t s_wb_err;
-
- /* AIO completions deferred from interrupt context */
- struct workqueue_struct *s_dio_done_wq;
- struct hlist_head s_pins;
-
- /*
- * Owning user namespace and default context in which to
- * interpret filesystem uids, gids, quotas, device nodes,
- * xattrs and security labels.
- */
- struct user_namespace *s_user_ns;
-
- /*
- * The list_lru structure is essentially just a pointer to a table
- * of per-node lru lists, each of which has its own spinlock.
- * There is no need to put them into separate cachelines.
- */
- struct list_lru s_dentry_lru;
- struct list_lru s_inode_lru;
- struct rcu_head rcu;
- struct work_struct destroy_work;
-
- struct mutex s_sync_lock; /* sync serialisation lock */
-
- /*
- * Indicates how deep in a filesystem stack this SB is
- */
- int s_stack_depth;
-
- /* s_inode_list_lock protects s_inodes */
- spinlock_t s_inode_list_lock ____cacheline_aligned_in_smp;
- struct list_head s_inodes; /* all inodes */
-
- spinlock_t s_inode_wblist_lock;
- struct list_head s_inodes_wb; /* writeback inodes */
-} __randomize_layout;
-
static inline struct user_namespace *i_user_ns(const struct inode *inode)
{
return inode->i_sb->s_user_ns;
@@ -2431,72 +2191,6 @@ extern loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
struct file *dst_file, loff_t dst_pos,
loff_t len, unsigned int remap_flags);
-/**
- * enum freeze_holder - holder of the freeze
- * @FREEZE_HOLDER_KERNEL: kernel wants to freeze or thaw filesystem
- * @FREEZE_HOLDER_USERSPACE: userspace wants to freeze or thaw filesystem
- * @FREEZE_MAY_NEST: whether nesting freeze and thaw requests is allowed
- * @FREEZE_EXCL: a freeze that can only be undone by the owner
- *
- * Indicate who the owner of the freeze or thaw request is and whether
- * the freeze needs to be exclusive or can nest.
- * Without @FREEZE_MAY_NEST, multiple freeze and thaw requests from the
- * same holder aren't allowed. It is however allowed to hold a single
- * @FREEZE_HOLDER_USERSPACE and a single @FREEZE_HOLDER_KERNEL freeze at
- * the same time. This is relied upon by some filesystems during online
- * repair or similar.
- */
-enum freeze_holder {
- FREEZE_HOLDER_KERNEL = (1U << 0),
- FREEZE_HOLDER_USERSPACE = (1U << 1),
- FREEZE_MAY_NEST = (1U << 2),
- FREEZE_EXCL = (1U << 3),
-};
-
-struct super_operations {
- struct inode *(*alloc_inode)(struct super_block *sb);
- void (*destroy_inode)(struct inode *);
- void (*free_inode)(struct inode *);
-
- void (*dirty_inode) (struct inode *, int flags);
- int (*write_inode) (struct inode *, struct writeback_control *wbc);
- int (*drop_inode) (struct inode *);
- void (*evict_inode) (struct inode *);
- void (*put_super) (struct super_block *);
- int (*sync_fs)(struct super_block *sb, int wait);
- int (*freeze_super) (struct super_block *, enum freeze_holder who, const void *owner);
- int (*freeze_fs) (struct super_block *);
- int (*thaw_super) (struct super_block *, enum freeze_holder who, const void *owner);
- int (*unfreeze_fs) (struct super_block *);
- int (*statfs) (struct dentry *, struct kstatfs *);
- int (*remount_fs) (struct super_block *, int *, char *);
- void (*umount_begin) (struct super_block *);
-
- int (*show_options)(struct seq_file *, struct dentry *);
- int (*show_devname)(struct seq_file *, struct dentry *);
- int (*show_path)(struct seq_file *, struct dentry *);
- int (*show_stats)(struct seq_file *, struct dentry *);
-#ifdef CONFIG_QUOTA
- ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
- ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
- struct dquot __rcu **(*get_dquots)(struct inode *);
-#endif
- long (*nr_cached_objects)(struct super_block *,
- struct shrink_control *);
- long (*free_cached_objects)(struct super_block *,
- struct shrink_control *);
- /*
- * If a filesystem can support graceful removal of a device and
- * continue read-write operations, implement this callback.
- *
- * Return 0 if the filesystem can continue read-write.
- * Non-zero return value or no such callback means the fs will be shutdown
- * as usual.
- */
- int (*remove_bdev)(struct super_block *sb, struct block_device *bdev);
- void (*shutdown)(struct super_block *sb);
-};
-
/*
* Inode flags - they have no relation to superblock flags now
*/
--git a/include/linux/fs_super_types.h b/include/linux/fs_super_types.h
new file mode 100644
index 000000000000..45cfd45b9fe0
--- /dev/null
+++ b/include/linux/fs_super_types.h
@@ -0,0 +1,335 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_FS_SUPER_TYPES_H
+#define _LINUX_FS_SUPER_TYPES_H
+
+#include <linux/fs_dirent.h>
+#include <linux/errseq.h>
+#include <linux/list_lru.h>
+#include <linux/list.h>
+#include <linux/list_bl.h>
+#include <linux/llist.h>
+#include <linux/uidgid.h>
+#include <linux/uuid.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/workqueue_types.h>
+#include <linux/quota.h>
+
+struct backing_dev_info;
+struct block_device;
+struct dentry;
+struct dentry_operations;
+struct dquot_operations;
+struct export_operations;
+struct file;
+struct file_system_type;
+struct fscrypt_operations;
+struct fsnotify_sb_info;
+struct fsverity_operations;
+struct kstatfs;
+struct mount;
+struct mtd_info;
+struct quotactl_ops;
+struct shrinker;
+struct unicode_map;
+struct user_namespace;
+struct workqueue_struct;
+struct writeback_control;
+struct xattr_handler;
+
+extern struct super_block *blockdev_superblock;
+
+/* Possible states of 'frozen' field */
+enum {
+ SB_UNFROZEN = 0, /* FS is unfrozen */
+ SB_FREEZE_WRITE = 1, /* Writes, dir ops, ioctls frozen */
+ SB_FREEZE_PAGEFAULT = 2, /* Page faults stopped as well */
+ SB_FREEZE_FS = 3, /* For internal FS use (e.g. to stop internal threads if needed) */
+ SB_FREEZE_COMPLETE = 4, /* ->freeze_fs finished successfully */
+};
+
+#define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
+
+struct sb_writers {
+ unsigned short frozen; /* Is sb frozen? */
+ int freeze_kcount; /* How many kernel freeze requests? */
+ int freeze_ucount; /* How many userspace freeze requests? */
+ const void *freeze_owner; /* Owner of the freeze */
+ struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS];
+};
+
+/**
+ * enum freeze_holder - holder of the freeze
+ * @FREEZE_HOLDER_KERNEL: kernel wants to freeze or thaw filesystem
+ * @FREEZE_HOLDER_USERSPACE: userspace wants to freeze or thaw filesystem
+ * @FREEZE_MAY_NEST: whether nesting freeze and thaw requests is allowed
+ * @FREEZE_EXCL: a freeze that can only be undone by the owner
+ *
+ * Indicate who the owner of the freeze or thaw request is and whether
+ * the freeze needs to be exclusive or can nest.
+ * Without @FREEZE_MAY_NEST, multiple freeze and thaw requests from the
+ * same holder aren't allowed. It is however allowed to hold a single
+ * @FREEZE_HOLDER_USERSPACE and a single @FREEZE_HOLDER_KERNEL freeze at
+ * the same time. This is relied upon by some filesystems during online
+ * repair or similar.
+ */
+enum freeze_holder {
+ FREEZE_HOLDER_KERNEL = (1U << 0),
+ FREEZE_HOLDER_USERSPACE = (1U << 1),
+ FREEZE_MAY_NEST = (1U << 2),
+ FREEZE_EXCL = (1U << 3),
+};
+
+struct super_operations {
+ struct inode *(*alloc_inode)(struct super_block *sb);
+ void (*destroy_inode)(struct inode *inode);
+ void (*free_inode)(struct inode *inode);
+ void (*dirty_inode)(struct inode *inode, int flags);
+ int (*write_inode)(struct inode *inode, struct writeback_control *wbc);
+ int (*drop_inode)(struct inode *inode);
+ void (*evict_inode)(struct inode *inode);
+ void (*put_super)(struct super_block *sb);
+ int (*sync_fs)(struct super_block *sb, int wait);
+ int (*freeze_super)(struct super_block *sb, enum freeze_holder who,
+ const void *owner);
+ int (*freeze_fs)(struct super_block *sb);
+ int (*thaw_super)(struct super_block *sb, enum freeze_holder who,
+ const void *owner);
+ int (*unfreeze_fs)(struct super_block *sb);
+ int (*statfs)(struct dentry *dentry, struct kstatfs *kstatfs);
+ int (*remount_fs) (struct super_block *, int *, char *);
+ void (*umount_begin)(struct super_block *sb);
+
+ int (*show_options)(struct seq_file *seq, struct dentry *dentry);
+ int (*show_devname)(struct seq_file *seq, struct dentry *dentry);
+ int (*show_path)(struct seq_file *seq, struct dentry *dentry);
+ int (*show_stats)(struct seq_file *seq, struct dentry *dentry);
+#ifdef CONFIG_QUOTA
+ ssize_t (*quota_read)(struct super_block *sb, int type, char *data,
+ size_t len, loff_t off);
+ ssize_t (*quota_write)(struct super_block *sb, int type,
+ const char *data, size_t len, loff_t off);
+ struct dquot __rcu **(*get_dquots)(struct inode *inode);
+#endif
+ long (*nr_cached_objects)(struct super_block *sb,
+ struct shrink_control *sc);
+ long (*free_cached_objects)(struct super_block *sb,
+ struct shrink_control *sc);
+ /*
+ * If a filesystem can support graceful removal of a device and
+ * continue read-write operations, implement this callback.
+ *
+ * Return 0 if the filesystem can continue read-write.
+ * Non-zero return value or no such callback means the fs will be shutdown
+ * as usual.
+ */
+ int (*remove_bdev)(struct super_block *sb, struct block_device *bdev);
+ void (*shutdown)(struct super_block *sb);
+};
+
+struct super_block {
+ struct list_head s_list; /* Keep this first */
+ dev_t s_dev; /* search index; _not_ kdev_t */
+ unsigned char s_blocksize_bits;
+ unsigned long s_blocksize;
+ loff_t s_maxbytes; /* Max file size */
+ struct file_system_type *s_type;
+ const struct super_operations *s_op;
+ const struct dquot_operations *dq_op;
+ const struct quotactl_ops *s_qcop;
+ const struct export_operations *s_export_op;
+ unsigned long s_flags;
+ unsigned long s_iflags; /* internal SB_I_* flags */
+ unsigned long s_magic;
+ struct dentry *s_root;
+ struct rw_semaphore s_umount;
+ int s_count;
+ atomic_t s_active;
+#ifdef CONFIG_SECURITY
+ void *s_security;
+#endif
+ const struct xattr_handler *const *s_xattr;
+#ifdef CONFIG_FS_ENCRYPTION
+ const struct fscrypt_operations *s_cop;
+ struct fscrypt_keyring *s_master_keys; /* master crypto keys in use */
+#endif
+#ifdef CONFIG_FS_VERITY
+ const struct fsverity_operations *s_vop;
+#endif
+#if IS_ENABLED(CONFIG_UNICODE)
+ struct unicode_map *s_encoding;
+ __u16 s_encoding_flags;
+#endif
+ struct hlist_bl_head s_roots; /* alternate root dentries for NFS */
+ struct mount *s_mounts; /* list of mounts; _not_ for fs use */
+ struct block_device *s_bdev; /* can go away once we use an accessor for @s_bdev_file */
+ struct file *s_bdev_file;
+ struct backing_dev_info *s_bdi;
+ struct mtd_info *s_mtd;
+ struct hlist_node s_instances;
+ unsigned int s_quota_types; /* Bitmask of supported quota types */
+ struct quota_info s_dquot; /* Diskquota specific options */
+
+ struct sb_writers s_writers;
+
+ /*
+ * Keep s_fs_info, s_time_gran, s_fsnotify_mask, and
+ * s_fsnotify_info together for cache efficiency. They are frequently
+ * accessed and rarely modified.
+ */
+ void *s_fs_info; /* Filesystem private info */
+
+ /* Granularity of c/m/atime in ns (cannot be worse than a second) */
+ u32 s_time_gran;
+ /* Time limits for c/m/atime in seconds */
+ time64_t s_time_min;
+ time64_t s_time_max;
+#ifdef CONFIG_FSNOTIFY
+ u32 s_fsnotify_mask;
+ struct fsnotify_sb_info *s_fsnotify_info;
+#endif
+
+ /*
+ * q: why are s_id and s_sysfs_name not the same? both are human
+ * readable strings that identify the filesystem
+ * a: s_id is allowed to change at runtime; it's used in log messages,
+ * and we want to when a device starts out as single device (s_id is dev
+ * name) but then a device is hot added and we have to switch to
+ * identifying it by UUID
+ * but s_sysfs_name is a handle for programmatic access, and can't
+ * change at runtime
+ */
+ char s_id[32]; /* Informational name */
+ uuid_t s_uuid; /* UUID */
+ u8 s_uuid_len; /* Default 16, possibly smaller for weird filesystems */
+
+ /* if set, fs shows up under sysfs at /sys/fs/$FSTYP/s_sysfs_name */
+ char s_sysfs_name[UUID_STRING_LEN + 1];
+
+ unsigned int s_max_links;
+ unsigned int s_d_flags; /* default d_flags for dentries */
+
+ /*
+ * The next field is for VFS *only*. No filesystems have any business
+ * even looking at it. You had been warned.
+ */
+ struct mutex s_vfs_rename_mutex; /* Kludge */
+
+ /*
+ * Filesystem subtype. If non-empty the filesystem type field
+ * in /proc/mounts will be "type.subtype"
+ */
+ const char *s_subtype;
+
+ const struct dentry_operations *__s_d_op; /* default d_op for dentries */
+
+ struct shrinker *s_shrink; /* per-sb shrinker handle */
+
+ /* Number of inodes with nlink == 0 but still referenced */
+ atomic_long_t s_remove_count;
+
+ /* Read-only state of the superblock is being changed */
+ int s_readonly_remount;
+
+ /* per-sb errseq_t for reporting writeback errors via syncfs */
+ errseq_t s_wb_err;
+
+ /* AIO completions deferred from interrupt context */
+ struct workqueue_struct *s_dio_done_wq;
+ struct hlist_head s_pins;
+
+ /*
+ * Owning user namespace and default context in which to
+ * interpret filesystem uids, gids, quotas, device nodes,
+ * xattrs and security labels.
+ */
+ struct user_namespace *s_user_ns;
+
+ /*
+ * The list_lru structure is essentially just a pointer to a table
+ * of per-node lru lists, each of which has its own spinlock.
+ * There is no need to put them into separate cachelines.
+ */
+ struct list_lru s_dentry_lru;
+ struct list_lru s_inode_lru;
+ struct rcu_head rcu;
+ struct work_struct destroy_work;
+
+ struct mutex s_sync_lock; /* sync serialisation lock */
+
+ /*
+ * Indicates how deep in a filesystem stack this SB is
+ */
+ int s_stack_depth;
+
+ /* s_inode_list_lock protects s_inodes */
+ spinlock_t s_inode_list_lock ____cacheline_aligned_in_smp;
+ struct list_head s_inodes; /* all inodes */
+
+ spinlock_t s_inode_wblist_lock;
+ struct list_head s_inodes_wb; /* writeback inodes */
+} __randomize_layout;
+
+/*
+ * sb->s_flags. Note that these mirror the equivalent MS_* flags where
+ * represented in both.
+ */
+#define SB_RDONLY BIT(0) /* Mount read-only */
+#define SB_NOSUID BIT(1) /* Ignore suid and sgid bits */
+#define SB_NODEV BIT(2) /* Disallow access to device special files */
+#define SB_NOEXEC BIT(3) /* Disallow program execution */
+#define SB_SYNCHRONOUS BIT(4) /* Writes are synced at once */
+#define SB_MANDLOCK BIT(6) /* Allow mandatory locks on an FS */
+#define SB_DIRSYNC BIT(7) /* Directory modifications are synchronous */
+#define SB_NOATIME BIT(10) /* Do not update access times. */
+#define SB_NODIRATIME BIT(11) /* Do not update directory access times */
+#define SB_SILENT BIT(15)
+#define SB_POSIXACL BIT(16) /* Supports POSIX ACLs */
+#define SB_INLINECRYPT BIT(17) /* Use blk-crypto for encrypted files */
+#define SB_KERNMOUNT BIT(22) /* this is a kern_mount call */
+#define SB_I_VERSION BIT(23) /* Update inode I_version field */
+#define SB_LAZYTIME BIT(25) /* Update the on-disk [acm]times lazily */
+
+/* These sb flags are internal to the kernel */
+#define SB_DEAD BIT(21)
+#define SB_DYING BIT(24)
+#define SB_FORCE BIT(27)
+#define SB_NOSEC BIT(28)
+#define SB_BORN BIT(29)
+#define SB_ACTIVE BIT(30)
+#define SB_NOUSER BIT(31)
+
+/* These flags relate to encoding and casefolding */
+#define SB_ENC_STRICT_MODE_FL (1 << 0)
+#define SB_ENC_NO_COMPAT_FALLBACK_FL (1 << 1)
+
+#define sb_has_strict_encoding(sb) \
+ (sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL)
+
+#if IS_ENABLED(CONFIG_UNICODE)
+#define sb_no_casefold_compat_fallback(sb) \
+ (sb->s_encoding_flags & SB_ENC_NO_COMPAT_FALLBACK_FL)
+#else
+#define sb_no_casefold_compat_fallback(sb) (1)
+#endif
+
+/* sb->s_iflags */
+#define SB_I_CGROUPWB 0x00000001 /* cgroup-aware writeback enabled */
+#define SB_I_NOEXEC 0x00000002 /* Ignore executables on this fs */
+#define SB_I_NODEV 0x00000004 /* Ignore devices on this fs */
+#define SB_I_STABLE_WRITES 0x00000008 /* don't modify blks until WB is done */
+
+/* sb->s_iflags to limit user namespace mounts */
+#define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */
+#define SB_I_IMA_UNVERIFIABLE_SIGNATURE 0x00000020
+#define SB_I_UNTRUSTED_MOUNTER 0x00000040
+#define SB_I_EVM_HMAC_UNSUPPORTED 0x00000080
+
+#define SB_I_SKIP_SYNC 0x00000100 /* Skip superblock at global sync */
+#define SB_I_PERSB_BDI 0x00000200 /* has a per-sb bdi */
+#define SB_I_TS_EXPIRY_WARNED 0x00000400 /* warned about timestamp range expiry */
+#define SB_I_RETIRED 0x00000800 /* superblock shouldn't be reused */
+#define SB_I_NOUMASK 0x00001000 /* VFS does not apply umask */
+#define SB_I_NOIDMAP 0x00002000 /* No idmapped mounts on this superblock */
+#define SB_I_ALLOW_HSM 0x00004000 /* Allow HSM events on this superblock */
+
+#endif /* _LINUX_FS_SUPER_TYPES_H */
--
2.47.3
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 3/3] fs: add fs_super.h header
2025-11-04 14:46 [PATCH 0/3] fs: start to split up fs.h Christian Brauner
2025-11-04 14:46 ` [PATCH 1/3] fs: rename fs_types.h to fs_dirent.h Christian Brauner
2025-11-04 14:46 ` [PATCH 2/3] fs: add fs_super_types header Christian Brauner
@ 2025-11-04 14:46 ` Christian Brauner
2025-11-05 12:55 ` [PATCH 0/3] fs: start to split up fs.h Christoph Hellwig
3 siblings, 0 replies; 7+ messages in thread
From: Christian Brauner @ 2025-11-04 14:46 UTC (permalink / raw)
To: linux-fsdevel; +Cc: Alexander Viro, Jan Kara, linux-kernel, Christian Brauner
Split out super block associated functions into a separate header.
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
| 220 +-------------------------------------------
| 233 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 234 insertions(+), 219 deletions(-)
--git a/include/linux/fs.h b/include/linux/fs.h
index 17fa9b64354b..1fde6bab3287 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2,7 +2,7 @@
#ifndef _LINUX_FS_H
#define _LINUX_FS_H
-#include <linux/fs_super_types.h>
+#include <linux/fs_super.h>
#include <linux/vfsdebug.h>
#include <linux/linkage.h>
#include <linux/wait_bit.h>
@@ -1662,66 +1662,6 @@ struct timespec64 simple_inode_init_ts(struct inode *inode);
* Snapshotting support.
*/
-/*
- * These are internal functions, please use sb_start_{write,pagefault,intwrite}
- * instead.
- */
-static inline void __sb_end_write(struct super_block *sb, int level)
-{
- percpu_up_read(sb->s_writers.rw_sem + level-1);
-}
-
-static inline void __sb_start_write(struct super_block *sb, int level)
-{
- percpu_down_read_freezable(sb->s_writers.rw_sem + level - 1, true);
-}
-
-static inline bool __sb_start_write_trylock(struct super_block *sb, int level)
-{
- return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
-}
-
-#define __sb_writers_acquired(sb, lev) \
- percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
-#define __sb_writers_release(sb, lev) \
- percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], _THIS_IP_)
-
-/**
- * __sb_write_started - check if sb freeze level is held
- * @sb: the super we write to
- * @level: the freeze level
- *
- * * > 0 - sb freeze level is held
- * * 0 - sb freeze level is not held
- * * < 0 - !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN
- */
-static inline int __sb_write_started(const struct super_block *sb, int level)
-{
- return lockdep_is_held_type(sb->s_writers.rw_sem + level - 1, 1);
-}
-
-/**
- * sb_write_started - check if SB_FREEZE_WRITE is held
- * @sb: the super we write to
- *
- * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
- */
-static inline bool sb_write_started(const struct super_block *sb)
-{
- return __sb_write_started(sb, SB_FREEZE_WRITE);
-}
-
-/**
- * sb_write_not_started - check if SB_FREEZE_WRITE is not held
- * @sb: the super we write to
- *
- * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
- */
-static inline bool sb_write_not_started(const struct super_block *sb)
-{
- return __sb_write_started(sb, SB_FREEZE_WRITE) <= 0;
-}
-
/**
* file_write_started - check if SB_FREEZE_WRITE is held
* @file: the file we write to
@@ -1752,118 +1692,6 @@ static inline bool file_write_not_started(const struct file *file)
return sb_write_not_started(file_inode(file)->i_sb);
}
-/**
- * sb_end_write - drop write access to a superblock
- * @sb: the super we wrote to
- *
- * Decrement number of writers to the filesystem. Wake up possible waiters
- * wanting to freeze the filesystem.
- */
-static inline void sb_end_write(struct super_block *sb)
-{
- __sb_end_write(sb, SB_FREEZE_WRITE);
-}
-
-/**
- * sb_end_pagefault - drop write access to a superblock from a page fault
- * @sb: the super we wrote to
- *
- * Decrement number of processes handling write page fault to the filesystem.
- * Wake up possible waiters wanting to freeze the filesystem.
- */
-static inline void sb_end_pagefault(struct super_block *sb)
-{
- __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
-}
-
-/**
- * sb_end_intwrite - drop write access to a superblock for internal fs purposes
- * @sb: the super we wrote to
- *
- * Decrement fs-internal number of writers to the filesystem. Wake up possible
- * waiters wanting to freeze the filesystem.
- */
-static inline void sb_end_intwrite(struct super_block *sb)
-{
- __sb_end_write(sb, SB_FREEZE_FS);
-}
-
-/**
- * sb_start_write - get write access to a superblock
- * @sb: the super we write to
- *
- * When a process wants to write data or metadata to a file system (i.e. dirty
- * a page or an inode), it should embed the operation in a sb_start_write() -
- * sb_end_write() pair to get exclusion against file system freezing. This
- * function increments number of writers preventing freezing. If the file
- * system is already frozen, the function waits until the file system is
- * thawed.
- *
- * Since freeze protection behaves as a lock, users have to preserve
- * ordering of freeze protection and other filesystem locks. Generally,
- * freeze protection should be the outermost lock. In particular, we have:
- *
- * sb_start_write
- * -> i_rwsem (write path, truncate, directory ops, ...)
- * -> s_umount (freeze_super, thaw_super)
- */
-static inline void sb_start_write(struct super_block *sb)
-{
- __sb_start_write(sb, SB_FREEZE_WRITE);
-}
-
-static inline bool sb_start_write_trylock(struct super_block *sb)
-{
- return __sb_start_write_trylock(sb, SB_FREEZE_WRITE);
-}
-
-/**
- * sb_start_pagefault - get write access to a superblock from a page fault
- * @sb: the super we write to
- *
- * When a process starts handling write page fault, it should embed the
- * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
- * exclusion against file system freezing. This is needed since the page fault
- * is going to dirty a page. This function increments number of running page
- * faults preventing freezing. If the file system is already frozen, the
- * function waits until the file system is thawed.
- *
- * Since page fault freeze protection behaves as a lock, users have to preserve
- * ordering of freeze protection and other filesystem locks. It is advised to
- * put sb_start_pagefault() close to mmap_lock in lock ordering. Page fault
- * handling code implies lock dependency:
- *
- * mmap_lock
- * -> sb_start_pagefault
- */
-static inline void sb_start_pagefault(struct super_block *sb)
-{
- __sb_start_write(sb, SB_FREEZE_PAGEFAULT);
-}
-
-/**
- * sb_start_intwrite - get write access to a superblock for internal fs purposes
- * @sb: the super we write to
- *
- * This is the third level of protection against filesystem freezing. It is
- * free for use by a filesystem. The only requirement is that it must rank
- * below sb_start_pagefault.
- *
- * For example filesystem can call sb_start_intwrite() when starting a
- * transaction which somewhat eases handling of freezing for internal sources
- * of filesystem changes (internal fs threads, discarding preallocation on file
- * close, etc.).
- */
-static inline void sb_start_intwrite(struct super_block *sb)
-{
- __sb_start_write(sb, SB_FREEZE_FS);
-}
-
-static inline bool sb_start_intwrite_trylock(struct super_block *sb)
-{
- return __sb_start_write_trylock(sb, SB_FREEZE_FS);
-}
-
bool inode_owner_or_capable(struct mnt_idmap *idmap,
const struct inode *inode);
@@ -2233,7 +2061,6 @@ extern loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
*/
#define __IS_FLG(inode, flg) ((inode)->i_sb->s_flags & (flg))
-static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags & SB_RDONLY; }
#define IS_RDONLY(inode) sb_rdonly((inode)->i_sb)
#define IS_SYNC(inode) (__IS_FLG(inode, SB_SYNCHRONOUS) || \
((inode)->i_flags & S_SYNC))
@@ -2467,10 +2294,6 @@ extern int unregister_filesystem(struct file_system_type *);
extern int vfs_statfs(const struct path *, struct kstatfs *);
extern int user_statfs(const char __user *, struct kstatfs *);
extern int fd_statfs(int, struct kstatfs *);
-int freeze_super(struct super_block *super, enum freeze_holder who,
- const void *freeze_owner);
-int thaw_super(struct super_block *super, enum freeze_holder who,
- const void *freeze_owner);
extern __printf(2, 3)
int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
extern int super_setup_bdi(struct super_block *sb);
@@ -2657,12 +2480,6 @@ extern struct kmem_cache *names_cachep;
#define __getname() kmem_cache_alloc(names_cachep, GFP_KERNEL)
#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
-extern struct super_block *blockdev_superblock;
-static inline bool sb_is_blkdev_sb(struct super_block *sb)
-{
- return IS_ENABLED(CONFIG_BLOCK) && sb == blockdev_superblock;
-}
-
void emergency_thaw_all(void);
extern int sync_filesystem(struct super_block *);
extern const struct file_operations def_blk_fops;
@@ -3117,9 +2934,6 @@ static inline void remove_inode_hash(struct inode *inode)
extern void inode_sb_list_add(struct inode *inode);
extern void inode_add_lru(struct inode *inode);
-extern int sb_set_blocksize(struct super_block *, int);
-extern int sb_min_blocksize(struct super_block *, int);
-
int generic_file_mmap(struct file *, struct vm_area_struct *);
int generic_file_mmap_prepare(struct vm_area_desc *desc);
int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
@@ -3439,38 +3253,6 @@ static inline bool generic_ci_validate_strict_name(struct inode *dir,
}
#endif
-static inline struct unicode_map *sb_encoding(const struct super_block *sb)
-{
-#if IS_ENABLED(CONFIG_UNICODE)
- return sb->s_encoding;
-#else
- return NULL;
-#endif
-}
-
-static inline bool sb_has_encoding(const struct super_block *sb)
-{
- return !!sb_encoding(sb);
-}
-
-/*
- * Compare if two super blocks have the same encoding and flags
- */
-static inline bool sb_same_encoding(const struct super_block *sb1,
- const struct super_block *sb2)
-{
-#if IS_ENABLED(CONFIG_UNICODE)
- if (sb1->s_encoding == sb2->s_encoding)
- return true;
-
- return (sb1->s_encoding && sb2->s_encoding &&
- (sb1->s_encoding->version == sb2->s_encoding->version) &&
- (sb1->s_encoding_flags == sb2->s_encoding_flags));
-#else
- return true;
-#endif
-}
-
int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
unsigned int ia_valid);
int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
--git a/include/linux/fs_super.h b/include/linux/fs_super.h
new file mode 100644
index 000000000000..2c8f4e61a5dd
--- /dev/null
+++ b/include/linux/fs_super.h
@@ -0,0 +1,233 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_FS_SUPER_H
+#define _LINUX_FS_SUPER_H
+
+#include <linux/fs_super_types.h>
+#include <linux/unicode.h>
+
+/*
+ * These are internal functions, please use sb_start_{write,pagefault,intwrite}
+ * instead.
+ */
+static inline void __sb_end_write(struct super_block *sb, int level)
+{
+ percpu_up_read(sb->s_writers.rw_sem + level - 1);
+}
+
+static inline void __sb_start_write(struct super_block *sb, int level)
+{
+ percpu_down_read_freezable(sb->s_writers.rw_sem + level - 1, true);
+}
+
+static inline bool __sb_start_write_trylock(struct super_block *sb, int level)
+{
+ return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
+}
+
+#define __sb_writers_acquired(sb, lev) \
+ percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev) - 1], 1, _THIS_IP_)
+#define __sb_writers_release(sb, lev) \
+ percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev) - 1], _THIS_IP_)
+
+/**
+ * __sb_write_started - check if sb freeze level is held
+ * @sb: the super we write to
+ * @level: the freeze level
+ *
+ * * > 0 - sb freeze level is held
+ * * 0 - sb freeze level is not held
+ * * < 0 - !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN
+ */
+static inline int __sb_write_started(const struct super_block *sb, int level)
+{
+ return lockdep_is_held_type(sb->s_writers.rw_sem + level - 1, 1);
+}
+
+/**
+ * sb_write_started - check if SB_FREEZE_WRITE is held
+ * @sb: the super we write to
+ *
+ * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
+ */
+static inline bool sb_write_started(const struct super_block *sb)
+{
+ return __sb_write_started(sb, SB_FREEZE_WRITE);
+}
+
+/**
+ * sb_write_not_started - check if SB_FREEZE_WRITE is not held
+ * @sb: the super we write to
+ *
+ * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
+ */
+static inline bool sb_write_not_started(const struct super_block *sb)
+{
+ return __sb_write_started(sb, SB_FREEZE_WRITE) <= 0;
+}
+
+/**
+ * sb_end_write - drop write access to a superblock
+ * @sb: the super we wrote to
+ *
+ * Decrement number of writers to the filesystem. Wake up possible waiters
+ * wanting to freeze the filesystem.
+ */
+static inline void sb_end_write(struct super_block *sb)
+{
+ __sb_end_write(sb, SB_FREEZE_WRITE);
+}
+
+/**
+ * sb_end_pagefault - drop write access to a superblock from a page fault
+ * @sb: the super we wrote to
+ *
+ * Decrement number of processes handling write page fault to the filesystem.
+ * Wake up possible waiters wanting to freeze the filesystem.
+ */
+static inline void sb_end_pagefault(struct super_block *sb)
+{
+ __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
+}
+
+/**
+ * sb_end_intwrite - drop write access to a superblock for internal fs purposes
+ * @sb: the super we wrote to
+ *
+ * Decrement fs-internal number of writers to the filesystem. Wake up possible
+ * waiters wanting to freeze the filesystem.
+ */
+static inline void sb_end_intwrite(struct super_block *sb)
+{
+ __sb_end_write(sb, SB_FREEZE_FS);
+}
+
+/**
+ * sb_start_write - get write access to a superblock
+ * @sb: the super we write to
+ *
+ * When a process wants to write data or metadata to a file system (i.e. dirty
+ * a page or an inode), it should embed the operation in a sb_start_write() -
+ * sb_end_write() pair to get exclusion against file system freezing. This
+ * function increments number of writers preventing freezing. If the file
+ * system is already frozen, the function waits until the file system is
+ * thawed.
+ *
+ * Since freeze protection behaves as a lock, users have to preserve
+ * ordering of freeze protection and other filesystem locks. Generally,
+ * freeze protection should be the outermost lock. In particular, we have:
+ *
+ * sb_start_write
+ * -> i_rwsem (write path, truncate, directory ops, ...)
+ * -> s_umount (freeze_super, thaw_super)
+ */
+static inline void sb_start_write(struct super_block *sb)
+{
+ __sb_start_write(sb, SB_FREEZE_WRITE);
+}
+
+static inline bool sb_start_write_trylock(struct super_block *sb)
+{
+ return __sb_start_write_trylock(sb, SB_FREEZE_WRITE);
+}
+
+/**
+ * sb_start_pagefault - get write access to a superblock from a page fault
+ * @sb: the super we write to
+ *
+ * When a process starts handling write page fault, it should embed the
+ * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
+ * exclusion against file system freezing. This is needed since the page fault
+ * is going to dirty a page. This function increments number of running page
+ * faults preventing freezing. If the file system is already frozen, the
+ * function waits until the file system is thawed.
+ *
+ * Since page fault freeze protection behaves as a lock, users have to preserve
+ * ordering of freeze protection and other filesystem locks. It is advised to
+ * put sb_start_pagefault() close to mmap_lock in lock ordering. Page fault
+ * handling code implies lock dependency:
+ *
+ * mmap_lock
+ * -> sb_start_pagefault
+ */
+static inline void sb_start_pagefault(struct super_block *sb)
+{
+ __sb_start_write(sb, SB_FREEZE_PAGEFAULT);
+}
+
+/**
+ * sb_start_intwrite - get write access to a superblock for internal fs purposes
+ * @sb: the super we write to
+ *
+ * This is the third level of protection against filesystem freezing. It is
+ * free for use by a filesystem. The only requirement is that it must rank
+ * below sb_start_pagefault.
+ *
+ * For example filesystem can call sb_start_intwrite() when starting a
+ * transaction which somewhat eases handling of freezing for internal sources
+ * of filesystem changes (internal fs threads, discarding preallocation on file
+ * close, etc.).
+ */
+static inline void sb_start_intwrite(struct super_block *sb)
+{
+ __sb_start_write(sb, SB_FREEZE_FS);
+}
+
+static inline bool sb_start_intwrite_trylock(struct super_block *sb)
+{
+ return __sb_start_write_trylock(sb, SB_FREEZE_FS);
+}
+
+static inline bool sb_rdonly(const struct super_block *sb)
+{
+ return sb->s_flags & SB_RDONLY;
+}
+
+static inline bool sb_is_blkdev_sb(struct super_block *sb)
+{
+ return IS_ENABLED(CONFIG_BLOCK) && sb == blockdev_superblock;
+}
+
+#if IS_ENABLED(CONFIG_UNICODE)
+static inline struct unicode_map *sb_encoding(const struct super_block *sb)
+{
+ return sb->s_encoding;
+}
+
+/* Compare if two super blocks have the same encoding and flags */
+static inline bool sb_same_encoding(const struct super_block *sb1,
+ const struct super_block *sb2)
+{
+ if (sb1->s_encoding == sb2->s_encoding)
+ return true;
+
+ return (sb1->s_encoding && sb2->s_encoding &&
+ (sb1->s_encoding->version == sb2->s_encoding->version) &&
+ (sb1->s_encoding_flags == sb2->s_encoding_flags));
+}
+#else
+static inline struct unicode_map *sb_encoding(const struct super_block *sb)
+{
+ return NULL;
+}
+
+static inline bool sb_same_encoding(const struct super_block *sb1,
+ const struct super_block *sb2)
+{
+ return true;
+}
+#endif
+
+static inline bool sb_has_encoding(const struct super_block *sb)
+{
+ return !!sb_encoding(sb);
+}
+
+int sb_set_blocksize(struct super_block *sb, int size);
+int sb_min_blocksize(struct super_block *sb, int size);
+
+int freeze_super(struct super_block *super, enum freeze_holder who,
+ const void *freeze_owner);
+int thaw_super(struct super_block *super, enum freeze_holder who,
+ const void *freeze_owner);
+
+#endif /* _LINUX_FS_SUPER_H */
--
2.47.3
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH 0/3] fs: start to split up fs.h
2025-11-04 14:46 [PATCH 0/3] fs: start to split up fs.h Christian Brauner
` (2 preceding siblings ...)
2025-11-04 14:46 ` [PATCH 3/3] fs: add fs_super.h header Christian Brauner
@ 2025-11-05 12:55 ` Christoph Hellwig
2025-11-05 13:13 ` Christian Brauner
3 siblings, 1 reply; 7+ messages in thread
From: Christoph Hellwig @ 2025-11-05 12:55 UTC (permalink / raw)
To: Christian Brauner; +Cc: linux-fsdevel, Alexander Viro, Jan Kara, linux-kernel
On Tue, Nov 04, 2025 at 03:46:31PM +0100, Christian Brauner wrote:
> Take first steps to split up fs.h. Add fs_super_types.h and fs_super.h
> headers that contain the types and functions associated with super
> blocks respectively.
We have this nice concept called directories for namespace prefixes.
Why not include/linux/fs/*.h for all these split out bits?
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH 0/3] fs: start to split up fs.h
2025-11-05 12:55 ` [PATCH 0/3] fs: start to split up fs.h Christoph Hellwig
@ 2025-11-05 13:13 ` Christian Brauner
2025-11-05 13:48 ` Christian Brauner
0 siblings, 1 reply; 7+ messages in thread
From: Christian Brauner @ 2025-11-05 13:13 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-fsdevel, Alexander Viro, Jan Kara, linux-kernel
On Wed, Nov 05, 2025 at 04:55:34AM -0800, Christoph Hellwig wrote:
> On Tue, Nov 04, 2025 at 03:46:31PM +0100, Christian Brauner wrote:
> > Take first steps to split up fs.h. Add fs_super_types.h and fs_super.h
> > headers that contain the types and functions associated with super
> > blocks respectively.
>
> We have this nice concept called directories for namespace prefixes.
> Why not include/linux/fs/*.h for all these split out bits?
Sure, fine by me. Some do it differently. For example, mm has mm_* too.
But yeah, the fs/ layout is fine.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 0/3] fs: start to split up fs.h
2025-11-05 13:13 ` Christian Brauner
@ 2025-11-05 13:48 ` Christian Brauner
0 siblings, 0 replies; 7+ messages in thread
From: Christian Brauner @ 2025-11-05 13:48 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-fsdevel, Alexander Viro, Jan Kara, linux-kernel
On Wed, Nov 05, 2025 at 02:13:32PM +0100, Christian Brauner wrote:
> On Wed, Nov 05, 2025 at 04:55:34AM -0800, Christoph Hellwig wrote:
> > On Tue, Nov 04, 2025 at 03:46:31PM +0100, Christian Brauner wrote:
> > > Take first steps to split up fs.h. Add fs_super_types.h and fs_super.h
> > > headers that contain the types and functions associated with super
> > > blocks respectively.
> >
> > We have this nice concept called directories for namespace prefixes.
> > Why not include/linux/fs/*.h for all these split out bits?
>
> Sure, fine by me. Some do it differently. For example, mm has mm_* too.
> But yeah, the fs/ layout is fine.
/me raises eye-brows:
blk-cgroup.h blkdev.h blk-mq.h blktrace_api.h
blk-crypto.h blk-integrity.h blkpg.h blk_types.h
blk-crypto-profile.h blk-mq-dma.h blk-pm.h
What sort of mix-and-match bonanza have you got going on over there?
^ permalink raw reply [flat|nested] 7+ messages in thread