diff options
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r-- | include/linux/fs.h | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index a83313f90fe3..455835d0e963 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1474,18 +1474,47 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb, kgid_has_mapping(fs_userns, kgid); } +struct timespec64 current_mgtime(struct inode *inode); struct timespec64 current_time(struct inode *inode); struct timespec64 inode_set_ctime_current(struct inode *inode); +/* + * Multigrain timestamps + * + * Conditionally use fine-grained ctime and mtime timestamps when there + * are users actively observing them via getattr. The primary use-case + * for this is NFS clients that use the ctime to distinguish between + * different states of the file, and that are often fooled by multiple + * operations that occur in the same coarse-grained timer tick. + * + * The kernel always keeps normalized struct timespec64 values in the ctime, + * which means that only the first 30 bits of the value are used. Use the + * 31st bit of the ctime's tv_nsec field as a flag to indicate that the value + * has been queried since it was last updated. + */ +#define I_CTIME_QUERIED (1L<<30) + /** * inode_get_ctime - fetch the current ctime from the inode * @inode: inode from which to fetch ctime * - * Grab the current ctime from the inode and return it. + * Grab the current ctime tv_nsec field from the inode, mask off the + * I_CTIME_QUERIED flag and return it. This is mostly intended for use by + * internal consumers of the ctime that aren't concerned with ensuring a + * fine-grained update on the next change (e.g. when preparing to store + * the value in the backing store for later retrieval). + * + * This is safe to call regardless of whether the underlying filesystem + * is using multigrain timestamps. */ static inline struct timespec64 inode_get_ctime(const struct inode *inode) { - return inode->__i_ctime; + struct timespec64 ctime; + + ctime.tv_sec = inode->__i_ctime.tv_sec; + ctime.tv_nsec = inode->__i_ctime.tv_nsec & ~I_CTIME_QUERIED; + + return ctime; } /** @@ -2259,6 +2288,7 @@ struct file_system_type { #define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */ #define FS_DISALLOW_NOTIFY_PERM 16 /* Disable fanotify permission events */ #define FS_ALLOW_IDMAP 32 /* FS has been updated to handle vfs idmappings. */ +#define FS_MGTIME 64 /* FS uses multigrain timestamps */ #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */ int (*init_fs_context)(struct fs_context *); const struct fs_parameter_spec *parameters; @@ -2282,6 +2312,17 @@ struct file_system_type { #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME) +/** + * is_mgtime: is this inode using multigrain timestamps + * @inode: inode to test for multigrain timestamps + * + * Return true if the inode uses multigrain timestamps, false otherwise. + */ +static inline bool is_mgtime(const struct inode *inode) +{ + return inode->i_sb->s_type->fs_flags & FS_MGTIME; +} + extern struct dentry *mount_bdev(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, int (*fill_super)(struct super_block *, void *, int)); @@ -2918,6 +2959,7 @@ extern void page_put_link(void *); extern int page_symlink(struct inode *inode, const char *symname, int len); extern const struct inode_operations page_symlink_inode_operations; extern void kfree_link(void *); +void fill_mg_cmtime(struct kstat *stat, u32 request_mask, struct inode *inode); void generic_fillattr(struct mnt_idmap *, u32, struct inode *, struct kstat *); void generic_fill_statx_attr(struct inode *inode, struct kstat *stat); extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int); |