| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20251104-work-fs-header-v1-2-fb39a2efe39e@kernel.org>
Date: Tue, 04 Nov 2025 15:46:33 +0100
From: Christian Brauner <brauner@...nel.org>
To: linux-fsdevel@...r.kernel.org
Cc: Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>,
linux-kernel@...r.kernel.org, Christian Brauner <brauner@...nel.org>
Subject: [PATCH 2/3] fs: add fs_super_types header
Split out super block associated structures into a separate header.
Signed-off-by: Christian Brauner <brauner@...nel.org>
---
include/linux/fs.h | 308 +------------------------------------
include/linux/fs_super_types.h | 335 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 336 insertions(+), 307 deletions(-)
diff --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
*/
diff --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
Powered by blists - more mailing lists