fs.h

讲述linux的初始化过程

	struct semaphore s_vfs_rename_sem;	/* Kludge */

	/* The next field is used by knfsd when converting a (inode number based)
	 * file handle into a dentry. As it builds a path in the dcache tree from
	 * the bottom up, there may for a time be a subpath of dentrys which is not
	 * connected to the main tree.  This semaphore ensure that there is only ever
	 * one such free path per filesystem.  Note that unconnected files (or other
	 * non-directories) are allowed, but not unconnected diretories.
	 */
	struct semaphore s_nfsd_free_path_sem;
};

/*
 * VFS helper functions..
 */
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, off_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);
};

/*
 * 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 *);
};

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 *);
};

/*
 * 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 *);
	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 (*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 *);
};

struct dquot_operations {
	void (*initialize) (struct inode *, short);
	void (*drop) (struct inode *);
	int (*alloc_block) (const struct inode *, unsigned long, char);
	int (*alloc_inode) (const struct inode *, unsigned long);
	void (*free_block) (const struct inode *, unsigned long);
	void (*free_inode) (const struct inode *, unsigned long);
	int (*transfer) (struct dentry *, 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 vfsmount *kern_mnt; /* For kernel mount, if it's FS_SINGLE fs */
	struct file_system_type * next;
};

#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 void kern_umount(struct vfsmount *);
extern int may_umount(struct vfsmount *);
extern long do_mount(char *, char *, char *, unsigned long, void *);


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;
}

extern inline int get_lease(struct inode *inode, unsigned int mode)
{
	if (inode->i_flock && (inode->i_flock->fl_flags & FL_LEASE))
		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 void bdput(struct block_device *);
extern int blkdev_open(struct inode *, struct file *);
extern struct file_operations def_blk_fops;
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 try_to_free_buffers(struct page *, int);
extern void refile_buffer(struct buffer_head * buf);

#define BUF_CLEAN	0
#define BUF_LOCKED	1	/* Buffers scheduled for write */
#define BUF_DIRTY	2	/* Dirty buffers, not yet scheduled for write */
#define BUF_PROTECTED	3	/* Ramdisk persistent storage */
#define NR_LIST		4

/*
 * 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);
}

#define atomic_set_buffer_protected(bh) test_and_set_bit(BH_Protected, &(bh)->b_state)

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

static inline void mark_buffer_protected(struct buffer_head * bh)
{
	if (!atomic_set_buffer_protected(bh))
		__mark_buffer_protected(bh);
}

extern void FASTCALL(__mark_buffer_dirty(struct buffer_head *bh));
extern void FASTCALL(mark_buffer_dirty(struct buffer_head *bh));

#define atomic_set_buffer_dirty(bh) test_and_set_bit(BH_Dirty, &(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);
}

extern void buffer_insert_inode_queue(struct buffer_head *, struct inode *);
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 balance_dirty(kdev_t);
extern int check_disk_change(kdev_t);
extern int invalidate_inodes(struct super_block *);
extern void invalidate_inode_pages(struct inode *);
extern void invalidate_inode_buffers(struct inode *);
#define invalidate_buffers(dev)	__invalidate_buffers((dev), 0)
#define destroy_buffers(dev)	__invalidate_buffers((dev), 1)
extern void __invalidate_buffers(kdev_t dev, int);
extern void sync_inodes(kdev_t);
extern void write_inode_now(struct inode *, int);
extern void sync_dev(kdev_t);