fs.h

一款linux的文件系统

 */
extern int vfs_create(struct inode *, struct dentry *, int);
extern int vfs_mkdir(struct inode *, struct dentry *, int);
extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
extern int vfs_symlink(struct inode *, struct dentry *, const char *);
extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
extern int vfs_rmdir(struct inode *, struct dentry *);
extern int vfs_unlink(struct inode *, struct dentry *);
extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);

/*
 * File types
 */
#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.
 */
typedef int (*filldir_t)(void *, const char *, int, loff_t, ino_t, unsigned);

struct block_device_operations {
	int (*open) (struct inode *, struct file *);
	int (*release) (struct inode *, struct file *);
	int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
	int (*check_media_change) (kdev_t);
	int (*revalidate) (kdev_t);
	struct module *owner;
};

/*
 * NOTE:
 * read, write, poll, fsync, readv, writev can be called
 *   without the big kernel lock held in all filesystems.
 */
struct file_operations {
	struct module *owner;
	loff_t (*llseek) (struct file *, loff_t, int);
	ssize_t (*read) (struct file *, char *, size_t, loff_t *);
	ssize_t (*write) (struct file *, const char *, size_t, loff_t *);
	int (*readdir) (struct file *, void *, filldir_t);
	unsigned int (*poll) (struct file *, struct poll_table_struct *);
	int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
	int (*mmap) (struct file *, struct vm_area_struct *);
	int (*open) (struct inode *, struct file *);
	int (*flush) (struct file *);
	int (*release) (struct inode *, struct file *);
	int (*fsync) (struct file *, struct dentry *, int datasync);
	int (*fasync) (int, struct file *, int);
	int (*lock) (struct file *, int, struct file_lock *);
	ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, loff_t *);
	ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, loff_t *);
	ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
	int (*dmapi_map_event) (struct file *, struct vm_area_struct *, unsigned int);
};

struct inode_operations {
	int (*create) (struct inode *,struct dentry *,int);
	struct dentry * (*lookup) (struct inode *,struct dentry *);
	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 *,int);
	int (*rmdir) (struct inode *,struct dentry *);
	int (*mknod) (struct inode *,struct dentry *,int,int);
	int (*rename) (struct inode *, struct dentry *,
			struct inode *, struct dentry *);
	int (*readlink) (struct dentry *, char *,int);
	int (*follow_link) (struct dentry *, struct nameidata *);
	void (*truncate) (struct inode *);
	int (*permission) (struct inode *, int);
	int (*revalidate) (struct dentry *);
	int (*setattr) (struct dentry *, struct iattr *);
	int (*getattr) (struct dentry *, struct iattr *);
	int (*setxattr) (struct dentry *, const char *, void *, size_t, int);
	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
	ssize_t (*listxattr) (struct dentry *, char *, size_t);
	int (*removexattr) (struct dentry *, const char *);
};

struct seq_file;

/*
 * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
 * without the big kernel lock held in all filesystems.
 */
struct super_operations {
	void (*read_inode) (struct inode *);
  
  	/* reiserfs kludge.  reiserfs needs 64 bits of information to
    	** find an inode.  We are using the read_inode2 call to get
   	** that information.  We don't like this, and are waiting on some
   	** VFS changes for the real solution.
   	** iget4 calls read_inode2, iff it is defined
   	*/
    	void (*read_inode2) (struct inode *, void *) ;
   	void (*dirty_inode) (struct inode *);
	void (*write_inode) (struct inode *, int);
	void (*put_inode) (struct inode *);
	void (*delete_inode) (struct inode *);
	void (*put_super) (struct super_block *);
	void (*write_super) (struct super_block *);
	int (*sync_fs) (struct super_block *);
	void (*write_super_lockfs) (struct super_block *);
	void (*unlockfs) (struct super_block *);
	int (*statfs) (struct super_block *, struct statfs *);
	int (*remount_fs) (struct super_block *, int *, char *);
	void (*clear_inode) (struct inode *);
	void (*umount_begin) (struct super_block *);

	/* Following are for knfsd to interact with "interesting" filesystems
	 * Currently just reiserfs, but possibly FAT and others later
	 *
	 * fh_to_dentry is given a filehandle fragement with length, and a type flag
	 *   and must return a dentry for the referenced object or, if "parent" is
	 *   set, a dentry for the parent of the object.
	 *   If a dentry cannot be found, a "root" dentry should be created and
	 *   flaged as DCACHE_NFSD_DISCONNECTED. nfsd_iget is an example implementation.
	 *
	 * dentry_to_fh is given a dentry and must generate the filesys specific
	 *   part of the file handle.  Available length is passed in *lenp and used
	 *   length should be returned therein.
	 *   If need_parent is set, then dentry_to_fh should encode sufficient information
	 *   to find the (current) parent.
	 *   dentry_to_fh should return a 1byte "type" which will be passed back in
	 *   the fhtype arguement to fh_to_dentry.  Type of 0 is reserved.
	 *   If filesystem was exportable before the introduction of fh_to_dentry,
	 *   types 1 and 2 should be used is that same way as the generic code.
	 *   Type 255 means error.
	 *
	 * Lengths are in units of 4bytes, not bytes.
	 */
	struct dentry * (*fh_to_dentry)(struct super_block *sb, __u32 *fh, int len, int fhtype, int parent);
	int (*dentry_to_fh)(struct dentry *, __u32 *fh, int *lenp, int need_parent);
	int (*show_options)(struct seq_file *, struct vfsmount *);
	int (*dmapi_mount_event) (struct super_block *, char *);
};

/* Inode state bits.. */
#define I_DIRTY_SYNC		1 /* Not dirty enough for O_DATASYNC */
#define I_DIRTY_DATASYNC	2 /* Data-related inode changes pending */
#define I_DIRTY_PAGES		4 /* Data-related inode changes pending */
#define I_LOCK			8
#define I_FREEING		16
#define I_CLEAR			32
#define I_NEW			64

#define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)

extern void __mark_inode_dirty(struct inode *, int);
static inline void mark_inode_dirty(struct inode *inode)
{
	__mark_inode_dirty(inode, I_DIRTY);
}

static inline void mark_inode_dirty_sync(struct inode *inode)
{
	__mark_inode_dirty(inode, I_DIRTY_SYNC);
}

static inline void mark_inode_dirty_pages(struct inode *inode)
{
	__mark_inode_dirty(inode, I_DIRTY_PAGES);
}

struct dquot_operations {
	void (*initialize) (struct inode *, short);
	void (*drop) (struct inode *);
	int (*alloc_space) (struct inode *, qsize_t, char);
	int (*alloc_inode) (const struct inode *, unsigned long);
	void (*free_space) (struct inode *, qsize_t);
	void (*free_inode) (const struct inode *, unsigned long);
	int (*transfer) (struct inode *, struct iattr *);
};

struct file_system_type {
	const char *name;
	int fs_flags;
	struct super_block *(*read_super) (struct super_block *, void *, int);
	struct module *owner;
	struct file_system_type * next;
	struct list_head fs_supers;
};

#define DECLARE_FSTYPE(var,type,read,flags) \
struct file_system_type var = { \
	name:		type, \
	read_super:	read, \
	fs_flags:	flags, \
	owner:		THIS_MODULE, \
}

#define DECLARE_FSTYPE_DEV(var,type,read) \
	DECLARE_FSTYPE(var,type,read,FS_REQUIRES_DEV)

/* Alas, no aliases. Too much hassle with bringing module.h everywhere */
#define fops_get(fops) \
	(((fops) && (fops)->owner)	\
		? ( try_inc_mod_count((fops)->owner) ? (fops) : NULL ) \
		: (fops))

#define fops_put(fops) \
do {	\
	if ((fops) && (fops)->owner) \
		__MOD_DEC_USE_COUNT((fops)->owner);	\
} while(0)

extern int register_filesystem(struct file_system_type *);
extern int unregister_filesystem(struct file_system_type *);
extern struct vfsmount *kern_mount(struct file_system_type *);
extern int may_umount(struct vfsmount *);
extern long do_mount(char *, char *, char *, unsigned long, void *);

#define kern_umount mntput

extern int vfs_statfs(struct super_block *, struct statfs *);

/* Return value for VFS lock functions - tells locks.c to lock conventionally
 * REALLY kosha for root NFS and nfs_lock
 */ 
#define LOCK_USE_CLNT 1

#define FLOCK_VERIFY_READ  1
#define FLOCK_VERIFY_WRITE 2

extern int locks_mandatory_locked(struct inode *);
extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);

/*
 * Candidates for mandatory locking have the setgid bit set
 * but no group execute bit -  an otherwise meaningless combination.
 */
#define MANDATORY_LOCK(inode) \
	(IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)

static inline int locks_verify_locked(struct inode *inode)
{
	if (MANDATORY_LOCK(inode))
		return locks_mandatory_locked(inode);
	return 0;
}

static inline int locks_verify_area(int read_write, struct inode *inode,
				    struct file *filp, loff_t offset,
				    size_t count)
{
	if (inode->i_flock && MANDATORY_LOCK(inode))
		return locks_mandatory_area(read_write, inode, filp, offset, count);
	return 0;
}

static inline int locks_verify_truncate(struct inode *inode,
				    struct file *filp,
				    loff_t size)
{
	if (inode->i_flock && MANDATORY_LOCK(inode))
		return locks_mandatory_area(
			FLOCK_VERIFY_WRITE, inode, filp,
			size < inode->i_size ? size : inode->i_size,
			(size < inode->i_size ? inode->i_size - size
			 : size - inode->i_size)
		);
	return 0;
}

static inline int get_lease(struct inode *inode, unsigned int mode)
{
	if (inode->i_flock)
		return __get_lease(inode, mode);
	return 0;
}

/* fs/open.c */

asmlinkage long sys_open(const char *, int, int);
asmlinkage long sys_close(unsigned int);	/* yes, it's really unsigned */
extern int do_truncate(struct dentry *, loff_t start);

extern struct file *filp_open(const char *, int, int);
extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
extern int filp_close(struct file *, fl_owner_t id);
extern char * getname(const char *);

/* fs/dcache.c */
extern void vfs_caches_init(unsigned long);

#define __getname()	kmem_cache_alloc(names_cachep, SLAB_KERNEL)
#define putname(name)	kmem_cache_free(names_cachep, (void *)(name))

enum {BDEV_FILE, BDEV_SWAP, BDEV_FS, BDEV_RAW};
extern int register_blkdev(unsigned int, const char *, struct block_device_operations *);
extern int unregister_blkdev(unsigned int, const char *);
extern struct block_device *bdget(dev_t);
extern int bd_acquire(struct inode *inode);
extern void bd_forget(struct inode *inode);
extern void bdput(struct block_device *);
extern struct char_device *cdget(dev_t);
extern void cdput(struct char_device *);
extern int blkdev_open(struct inode *, struct file *);
extern int blkdev_close(struct inode *, struct file *);
extern struct file_operations def_blk_fops;
extern struct address_space_operations def_blk_aops;
extern struct file_operations def_fifo_fops;
extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
extern int blkdev_get(struct block_device *, mode_t, unsigned, int);
extern int blkdev_put(struct block_device *, int);

/* fs/devices.c */
extern const struct block_device_operations *get_blkfops(unsigned int);
extern int register_chrdev(unsigned int, const char *, struct file_operations *);
extern int unregister_chrdev(unsigned int, const char *);
extern int chrdev_open(struct inode *, struct file *);
extern const char * bdevname(kdev_t);
extern const char * cdevname(kdev_t);
extern const char * kdevname(kdev_t);
extern void init_special_inode(struct inode *, umode_t, int);

/* Invalid inode operations -- fs/bad_inode.c */
extern void make_bad_inode(struct inode *);
extern int is_bad_inode(struct inode *);

extern struct file_operations read_fifo_fops;
extern struct file_operations write_fifo_fops;
extern struct file_operations rdwr_fifo_fops;
extern struct file_operations read_pipe_fops;
extern struct file_operations write_pipe_fops;
extern struct file_operations rdwr_pipe_fops;

extern int fs_may_remount_ro(struct super_block *);

extern int FASTCALL(try_to_free_buffers(struct page *, unsigned int));
extern void refile_buffer(struct buffer_head * buf);
extern void create_empty_buffers(struct page *, kdev_t, unsigned long);
extern void end_buffer_io_sync(struct buffer_head *bh, int uptodate);

/* reiserfs_writepage needs this */
extern void set_buffer_async_io(struct buffer_head *bh) ;

#define BUF_CLEAN	0
#define BUF_LOCKED	1	/* Buffers scheduled for write */
#define BUF_DIRTY	2	/* Dirty buffers, not yet scheduled for write */
#define NR_LIST		3

static inline void get_bh(struct buffer_head * bh)
{
        atomic_inc(&(bh)->b_count);
}

static inline void put_bh(struct buffer_head *bh)
{
        smp_mb__before_atomic_dec();
        atomic_dec(&bh->b_count);
}

/*
 * This is called by bh->b_end_io() handlers when I/O has completed.
 */
static inline void mark_buffer_uptodate(struct buffer_head * bh, int on)
{
	if (on)
		set_bit(BH_Uptodate, &bh->b_state);
	else
		clear_bit(BH_Uptodate, &bh->b_state);
}

#define atomic_set_buffer_clean(bh) test_and_clear_bit(BH_Dirty, &(bh)->b_state)

static inline void __mark_buffer_clean(struct buffer_head *bh)
{
	refile_buffer(bh);
}

static inline void mark_buffer_clean(struct buffer_head * bh)
{
	if (atomic_set_buffer_clean(bh))
		__mark_buffer_clean(bh);
}

extern void FASTCALL(__mark_dirty(struct buffer_head *bh));
extern void FASTCALL(__mark_buffer_dirty(struct buffer_head *bh));
extern void FASTCALL(mark_buffer_dirty(struct buffer_head *bh));
extern void FASTCALL(buffer_insert_inode_queue(struct buffer_head *, struct inode *));
extern void FASTCALL(buffer_insert_inode_data_queue(struct buffer_head *, struct inode *));

static inline int atomic_set_buffer_dirty(struct buffer_head *bh)
{
	return test_and_set_bit(BH_Dirty, &bh->b_state);
}

static inline void mark_buffer_async(struct buffer_head * bh, int on)
{
	if (on)
		set_bit(BH_Async, &bh->b_state);
	else
		clear_bit(BH_Async, &bh->b_state);
}

/*
 * If an error happens during the make_request, this function
 * has to be recalled. It marks the buffer as clean and not
 * uptodate, and it notifys the upper layer about the end
 * of the I/O.
 */
static inline void buffer_IO_error(struct buffer_head * bh)
{
	mark_buffer_clean(bh);
	/*
	 * b_end_io has to clear the BH_Uptodate bitflag in the error case!
	 */
	bh->b_end_io(bh, 0);
}

static inline void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode)
{
	mark_buffer_dirty(bh);
	buffer_insert_inode_queue(bh, inode);
}

extern void set_buffer_flushtime(struct buffer_head *);
extern void balance_dirty(void);