#ifndef _LINUX_FS_H #define _LINUX_FS_H #include #include #include #include #include #include #include #include /* Page cache limit. The filesystems should put that into their s_maxbytes limits, otherwise bad things can happen in VM. */ #if BITS_PER_LONG==32 #define MAX_LFS_FILESIZE (((loff_t)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) #elif BITS_PER_LONG==64 #define MAX_LFS_FILESIZE ((loff_t)0x7fffffffffffffffLL) #endif /* * File types * * NOTE! These match bits 12..15 of stat.st_mode * (ie "(i_mode >> 12) & 15"). */ #define DT_UNKNOWN 0 #define DT_FIFO 1 #define DT_CHR 2 #define DT_DIR 4 #define DT_BLK 6 #define DT_REG 8 #define DT_LNK 10 #define DT_SOCK 12 #define DT_WHT 14 /* * This is the "filldir" function type, used by readdir() to let * the kernel specify what kind of dirent layout it wants to have. * This allows the kernel to read directories into kernel space or * to have different dirent layouts depending on the binary type. */ struct dir_context; typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64, unsigned); struct dir_context { const filldir_t actor; loff_t pos; }; /* * sb->s_flags. Note that these mirror the equivalent MS_* flags where * represented in both. */ #define SB_RDONLY 1 /* Mount read-only */ #define SB_NOSUID 2 /* Ignore suid and sgid bits */ #define SB_NODEV 4 /* Disallow access to device special files */ #define SB_NOEXEC 8 /* Disallow program execution */ #define SB_SYNCHRONOUS 16 /* Writes are synced at once */ #define SB_MANDLOCK 64 /* Allow mandatory locks on an FS */ #define SB_DIRSYNC 128 /* Directory modifications are synchronous */ #define SB_NOATIME 1024 /* Do not update access times. */ #define SB_NODIRATIME 2048 /* Do not update directory access times */ #define SB_SILENT 32768 #define SB_POSIXACL (1<<16) /* VFS does not apply the umask */ #define SB_KERNMOUNT (1<<22) /* this is a kern_mount call */ #define SB_I_VERSION (1<<23) /* Update inode I_version field */ #define SB_LAZYTIME (1<<25) /* Update the on-disk [acm]times lazily */ /* * These are the fs-independent mount-flags: up to 32 flags are supported */ #define MS_RDONLY 1 /* Mount read-only */ #define MS_NOSUID 2 /* Ignore suid and sgid bits */ #define MS_NODEV 4 /* Disallow access to device special files */ #define MS_NOEXEC 8 /* Disallow program execution */ #define MS_SYNCHRONOUS 16 /* Writes are synced at once */ #define MS_REMOUNT 32 /* Alter flags of a mounted FS */ #define MS_MANDLOCK 64 /* Allow mandatory locks on an FS */ #define MS_DIRSYNC 128 /* Directory modifications are synchronous */ #define MS_NOATIME 1024 /* Do not update access times. */ #define MS_NODIRATIME 2048 /* Do not update directory access times */ #define MS_BIND 4096 #define MS_MOVE 8192 #define MS_REC 16384 #define MS_VERBOSE 32768 /* War is peace. Verbosity is silence. MS_VERBOSE is deprecated. */ #define MS_SILENT 32768 #define MS_POSIXACL (1<<16) /* VFS does not apply the umask */ #define MS_UNBINDABLE (1<<17) /* change to unbindable */ #define MS_PRIVATE (1<<18) /* change to private */ #define MS_SLAVE (1<<19) /* change to slave */ #define MS_SHARED (1<<20) /* change to shared */ #define MS_RELATIME (1<<21) /* Update atime relative to mtime/ctime. */ #define MS_KERNMOUNT (1<<22) /* this is a kern_mount call */ #define MS_I_VERSION (1<<23) /* Update inode I_version field */ #define MS_ACTIVE (1<<30) #define MS_NOUSER (1<<31) #define SEEK_SET 0 /* seek relative to beginning of file */ #define SEEK_CUR 1 /* seek relative to current file position */ #define SEEK_END 2 /* seek relative to end of file */ #define SEEK_DATA 3 /* seek to the next data */ #define SEEK_HOLE 4 /* seek to the next hole */ #define SEEK_MAX SEEK_HOLE struct inode { struct hlist_node i_hash; struct list_head i_list; struct list_head i_sb_list; struct list_head i_dentry; unsigned long i_ino; /* * Filesystems may only read i_nlink directly. They shall use the * following functions for modification: * * (set|clear|inc|drop)_nlink * inode_(inc|dec)_link_count */ union { const unsigned int i_nlink; unsigned int __i_nlink; }; uid_t i_uid; gid_t i_gid; u64 i_version; loff_t i_size; struct timespec i_atime; struct timespec i_mtime; struct timespec i_ctime; unsigned int i_blkbits; blkcnt_t i_blocks; unsigned short i_bytes; umode_t i_mode; const struct inode_operations *i_op; const struct file_operations *i_fop; /* former ->i_op->default_file_ops */ struct super_block *i_sb; __u32 i_generation; unsigned long i_state; unsigned int i_flags; unsigned int i_count; char *i_link; void *i_private; /* fs or device private pointer */ }; struct super_block { struct list_head s_list; /* Keep this first */ dev_t s_dev; /* search index; _not_ kdev_t */ unsigned long s_blocksize; unsigned char s_blocksize_bits; unsigned char s_dirt; unsigned long long s_maxbytes; /* Max file size */ struct file_system_type *s_type; const struct super_operations *s_op; struct dquot_operations *dq_op; struct quotactl_ops *s_qcop; const struct export_operations *s_export_op; unsigned long s_flags; unsigned long s_magic; struct dentry *s_root; struct rw_semaphore s_umount; struct mutex s_lock; int s_count; int s_syncing; int s_need_sync_fs; #ifdef CONFIG_SECURITY void *s_security; #endif struct xattr_handler **s_xattr; struct list_head s_inodes; /* all inodes */ struct list_head s_dirty; /* dirty inodes */ struct list_head s_io; /* parked for writeback */ struct list_head s_more_io; /* parked for more writeback */ struct hlist_head s_anon; /* anonymous dentries for (nfs) exporting */ struct list_head s_files; /* s_dentry_lru and s_nr_dentry_unused are protected by dcache_lock */ struct list_head s_dentry_lru; /* unused dentry lru */ int s_nr_dentry_unused; /* # of dentry on lru */ struct block_device *s_bdev; struct mtd_info *s_mtd; struct hlist_node s_instances; int s_frozen; wait_queue_head_t s_wait_unfrozen; char s_id[32]; /* Informational name */ void *s_fs_info; /* Filesystem private info */ /* * 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 */ /* Granularity of c/m/atime in ns. Cannot be worse than a second */ u32 s_time_gran; /* Number of inodes with nlink == 0 but still referenced */ const struct dentry_operations *s_d_op; /* default d_op for dentries */ }; struct file_system_type { const char *name; int fs_flags; int (*get_sb) (struct file_system_type *, int, const char *, void *, struct vfsmount *); void (*kill_sb) (struct super_block *); struct module *owner; struct file_system_type * next; struct hlist_head fs_supers; }; struct file { struct path f_path; struct inode *f_inode; /* cached value */ #define f_dentry f_path.dentry #define f_vfsmnt f_path.mnt const struct file_operations *f_op; unsigned int f_flags; loff_t f_pos; unsigned int f_uid, f_gid; u64 f_version; #ifdef CONFIG_SECURITY void *f_security; #endif /* needed for tty driver, and maybe others */ void *private_data; #ifdef CONFIG_EPOLL /* Used by fs/eventpoll.c to link all the hooks to this file */ struct list_head f_ep_links; spinlock_t f_ep_lock; #endif /* #ifdef CONFIG_EPOLL */ #ifdef CONFIG_DEBUG_WRITECOUNT unsigned long f_mnt_write_state; #endif }; struct super_operations { struct inode *(*alloc_inode)(struct super_block *sb); void (*destroy_inode)(struct inode *); }; static inline struct inode *file_inode(const struct file *f) { return f->f_inode; } /* * Inode flags - they have no relation to superblock flags now */ #define S_SYNC 1 /* Writes are synced at once */ #define S_NOATIME 2 /* Do not update access times */ #define S_APPEND 4 /* Append-only file */ #define S_IMMUTABLE 8 /* Immutable file */ #define S_DEAD 16 /* removed, but still open directory */ #define S_NOQUOTA 32 /* Inode is not counted to quota */ #define S_DIRSYNC 64 /* Directory modifications are synchronous */ #define S_NOCMTIME 128 /* Do not update file c/mtime */ #define S_SWAPFILE 256 /* Do not truncate: swapon got its bmaps */ #define S_PRIVATE 512 /* Inode is fs-internal */ #define S_IMA 1024 /* Inode has an associated IMA struct */ #define S_AUTOMOUNT 2048 /* Automount/referral quasi-directory */ #define S_NOSEC 4096 /* no suid or xattr security attributes */ #ifdef CONFIG_FS_DAX #define S_DAX 8192 /* Direct Access, avoiding the page cache */ #else #define S_DAX 0 /* Make all the DAX code disappear */ #endif /* * Note that nosuid etc flags are inode-specific: setting some file-system * flags just means all the inodes inherit those flags by default. It might be * possible to override it selectively if you really wanted to with some * ioctl() that is not currently implemented. * * Exception: MS_RDONLY is always applied to the entire file system. * * Unfortunately, it is possible to change a filesystems flags with it mounted * with files in use. This means that all of the inodes will not have their * i_flags updated. Hence, i_flags no longer inherit the superblock mount * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org */ #define __IS_FLG(inode, flg) ((inode)->i_sb->s_flags & (flg)) #define IS_RDONLY(inode) ((inode)->i_sb->s_flags & MS_RDONLY) #define IS_SYNC(inode) (__IS_FLG(inode, MS_SYNCHRONOUS) || \ ((inode)->i_flags & S_SYNC)) #define IS_DIRSYNC(inode) (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \ ((inode)->i_flags & (S_SYNC|S_DIRSYNC))) #define IS_MANDLOCK(inode) __IS_FLG(inode, MS_MANDLOCK) #define IS_NOATIME(inode) __IS_FLG(inode, MS_RDONLY|MS_NOATIME) #define IS_I_VERSION(inode) __IS_FLG(inode, MS_I_VERSION) #define IS_NOQUOTA(inode) ((inode)->i_flags & S_NOQUOTA) #define IS_APPEND(inode) ((inode)->i_flags & S_APPEND) #define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE) #define IS_POSIXACL(inode) __IS_FLG(inode, MS_POSIXACL) #define IS_DEADDIR(inode) ((inode)->i_flags & S_DEAD) #define IS_NOCMTIME(inode) ((inode)->i_flags & S_NOCMTIME) #define IS_SWAPFILE(inode) ((inode)->i_flags & S_SWAPFILE) #define IS_PRIVATE(inode) ((inode)->i_flags & S_PRIVATE) #define IS_IMA(inode) ((inode)->i_flags & S_IMA) #define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT) #define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC) #define IS_DAX(inode) ((inode)->i_flags & S_DAX) #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ (inode)->i_rdev == WHITEOUT_DEV) /* * Inode state bits. Protected by inode->i_lock * * Three bits determine the dirty state of the inode, I_DIRTY_SYNC, * I_DIRTY_DATASYNC and I_DIRTY_PAGES. * * Four bits define the lifetime of an inode. Initially, inodes are I_NEW, * until that flag is cleared. I_WILL_FREE, I_FREEING and I_CLEAR are set at * various stages of removing an inode. * * Two bits are used for locking and completion notification, I_NEW and I_SYNC. * * I_DIRTY_SYNC Inode is dirty, but doesn't have to be written on * fdatasync(). i_atime is the usual cause. * I_DIRTY_DATASYNC Data-related inode changes pending. We keep track of * these changes separately from I_DIRTY_SYNC so that we * don't have to write inode on fdatasync() when only * mtime has changed in it. * I_DIRTY_PAGES Inode has dirty pages. Inode itself may be clean. * I_NEW Serves as both a mutex and completion notification. * New inodes set I_NEW. If two processes both create * the same inode, one of them will release its inode and * wait for I_NEW to be released before returning. * Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can * also cause waiting on I_NEW, without I_NEW actually * being set. find_inode() uses this to prevent returning * nearly-dead inodes. * I_WILL_FREE Must be set when calling write_inode_now() if i_count * is zero. I_FREEING must be set when I_WILL_FREE is * cleared. * I_FREEING Set when inode is about to be freed but still has dirty * pages or buffers attached or the inode itself is still * dirty. * I_CLEAR Added by clear_inode(). In this state the inode is * clean and can be destroyed. Inode keeps I_FREEING. * * Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are * prohibited for many purposes. iget() must wait for * the inode to be completely released, then create it * anew. Other functions will just ignore such inodes, * if appropriate. I_NEW is used for waiting. * * I_SYNC Writeback of inode is running. The bit is set during * data writeback, and cleared with a wakeup on the bit * address once it is done. The bit is also used to pin * the inode in memory for flusher thread. * * I_REFERENCED Marks the inode as recently references on the LRU list. * * I_DIO_WAKEUP Never set. Only used as a key for wait_on_bit(). * * I_WB_SWITCH Cgroup bdi_writeback switching in progress. Used to * synchronize competing switching instances and to tell * wb stat updates to grab mapping->tree_lock. See * inode_switch_wb_work_fn() for details. * * Q: What is the difference between I_WILL_FREE and I_FREEING? */ #define I_DIRTY_SYNC (1 << 0) #define I_DIRTY_DATASYNC (1 << 1) #define I_DIRTY_PAGES (1 << 2) #define __I_NEW 3 #define I_NEW (1 << __I_NEW) #define I_WILL_FREE (1 << 4) #define I_FREEING (1 << 5) #define I_CLEAR (1 << 6) #define __I_SYNC 7 #define I_SYNC (1 << __I_SYNC) #define I_REFERENCED (1 << 8) #define __I_DIO_WAKEUP 9 #define I_DIO_WAKEUP (1 << __I_DIO_WAKEUP) #define I_LINKABLE (1 << 10) #define I_DIRTY_TIME (1 << 11) #define __I_DIRTY_TIME_EXPIRED 12 #define I_DIRTY_TIME_EXPIRED (1 << __I_DIRTY_TIME_EXPIRED) #define I_WB_SWITCH (1 << 13) #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES) #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME) static inline loff_t i_size_read(const struct inode *inode) { return inode->i_size; } struct inode *new_inode(struct super_block *sb); unsigned int get_next_ino(void); void iput(struct inode *); struct inode *iget(struct inode *); void inc_nlink(struct inode *inode); void clear_nlink(struct inode *inode); void set_nlink(struct inode *inode, unsigned int nlink); struct inode_operations { struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int); const char *(*get_link) (struct dentry *dentry, struct inode *inode); int (*create) (struct inode *,struct dentry *, umode_t); int (*link) (struct dentry *,struct inode *,struct dentry *); int (*unlink) (struct inode *,struct dentry *); int (*symlink) (struct inode *,struct dentry *,const char *); int (*mkdir) (struct inode *,struct dentry *,umode_t); int (*rmdir) (struct inode *,struct dentry *); int (*rename) (struct inode *, struct dentry *, struct inode *, struct dentry *, unsigned int); }; static inline ino_t parent_ino(struct dentry *dentry) { return dentry->d_parent->d_inode->i_ino; } static inline bool dir_emit(struct dir_context *ctx, const char *name, int namelen, u64 ino, unsigned type) { return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0; } static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx) { return ctx->actor(ctx, ".", 1, ctx->pos, file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0; } static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx) { return ctx->actor(ctx, "..", 2, ctx->pos, parent_ino(file->f_path.dentry), DT_DIR) == 0; } static inline int dir_emit_dots(struct file *file, struct dir_context *ctx) { if (ctx->pos == 0) { dir_emit_dot(file, ctx); ctx->pos = 1; } if (ctx->pos == 1) { dir_emit_dotdot(file, ctx); ctx->pos = 2; } return true; } struct file_operations { int (*iterate) (struct file *, struct dir_context *); ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); int (*ioctl) (struct file *, int request, void *buf); int (*truncate) (struct file *, loff_t); }; void drop_nlink(struct inode *inode); extern const struct file_operations simple_dir_operations; extern const struct inode_operations simple_symlink_inode_operations; int simple_empty(struct dentry *dentry); int simple_unlink(struct inode *dir, struct dentry *dentry); int simple_rmdir(struct inode *dir, struct dentry *dentry); struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags); int dcache_readdir(struct file *, struct dir_context *); const char *simple_get_link(struct dentry *dentry, struct inode *inode); struct inode *iget_locked(struct super_block *, unsigned long); void iget_failed(struct inode *inode); #endif /* _LINUX_FS_H */