fs.h

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static inline void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
{
	/* per-mountpoint checks will go here */
	update_atime(dentry->d_inode);
}

static inline void file_accessed(struct file *file)
{
	if (!(file->f_flags & O_NOATIME))
		touch_atime(file->f_vfsmnt, file->f_dentry);
}

int sync_inode(struct inode *inode, struct writeback_control *wbc);

/**
 * struct export_operations - for nfsd to communicate with file systems
 * @decode_fh:      decode a file handle fragment and return a &struct dentry
 * @encode_fh:      encode a file handle fragment from a dentry
 * @get_name:       find the name for a given inode in a given directory
 * @get_parent:     find the parent of a given directory
 * @get_dentry:     find a dentry for the inode given a file handle sub-fragment
 *
 * Description:
 *    The export_operations structure provides a means for nfsd to communicate
 *    with a particular exported file system  - particularly enabling nfsd and
 *    the filesystem to co-operate when dealing with file handles.
 *
 *    export_operations contains two basic operation for dealing with file
 *    handles, decode_fh() and encode_fh(), and allows for some other
 *    operations to be defined which standard helper routines use to get
 *    specific information from the filesystem.
 *
 *    nfsd encodes information use to determine which filesystem a filehandle
 *    applies to in the initial part of the file handle.  The remainder, termed
 *    a file handle fragment, is controlled completely by the filesystem.  The
 *    standard helper routines assume that this fragment will contain one or
 *    two sub-fragments, one which identifies the file, and one which may be
 *    used to identify the (a) directory containing the file.
 *
 *    In some situations, nfsd needs to get a dentry which is connected into a
 *    specific part of the file tree.  To allow for this, it passes the
 *    function acceptable() together with a @context which can be used to see
 *    if the dentry is acceptable.  As there can be multiple dentrys for a
 *    given file, the filesystem should check each one for acceptability before
 *    looking for the next.  As soon as an acceptable one is found, it should
 *    be returned.
 *
 * decode_fh:
 *    @decode_fh is given a &struct super_block (@sb), a file handle fragment
 *    (@fh, @fh_len) and an acceptability testing function (@acceptable,
 *    @context).  It should return a &struct dentry which refers to the same
 *    file that the file handle fragment refers to,  and which passes the
 *    acceptability test.  If it cannot, it should return a %NULL pointer if
 *    the file was found but no acceptable &dentries were available, or a
 *    %ERR_PTR error code indicating why it couldn't be found (e.g. %ENOENT or
 *    %ENOMEM).
 *
 * encode_fh:
 *    @encode_fh should store in the file handle fragment @fh (using at most
 *    @max_len bytes) information that can be used by @decode_fh to recover the
 *    file refered to by the &struct dentry @de.  If the @connectable flag is
 *    set, the encode_fh() should store sufficient information so that a good
 *    attempt can be made to find not only the file but also it's place in the
 *    filesystem.   This typically means storing a reference to de->d_parent in
 *    the filehandle fragment.  encode_fh() should return the number of bytes
 *    stored or a negative error code such as %-ENOSPC
 *
 * get_name:
 *    @get_name should find a name for the given @child in the given @parent
 *    directory.  The name should be stored in the @name (with the
 *    understanding that it is already pointing to a a %NAME_MAX+1 sized
 *    buffer.   get_name() should return %0 on success, a negative error code
 *    or error.  @get_name will be called without @parent->i_sem held.
 *
 * get_parent:
 *    @get_parent should find the parent directory for the given @child which
 *    is also a directory.  In the event that it cannot be found, or storage
 *    space cannot be allocated, a %ERR_PTR should be returned.
 *
 * get_dentry:
 *    Given a &super_block (@sb) and a pointer to a file-system specific inode
 *    identifier, possibly an inode number, (@inump) get_dentry() should find
 *    the identified inode and return a dentry for that inode.  Any suitable
 *    dentry can be returned including, if necessary, a new dentry created with
 *    d_alloc_root.  The caller can then find any other extant dentrys by
 *    following the d_alias links.  If a new dentry was created using
 *    d_alloc_root, DCACHE_NFSD_DISCONNECTED should be set, and the dentry
 *    should be d_rehash()ed.
 *
 *    If the inode cannot be found, either a %NULL pointer or an %ERR_PTR code
 *    can be returned.  The @inump will be whatever was passed to
 *    nfsd_find_fh_dentry() in either the @obj or @parent parameters.
 *
 * Locking rules:
 *    get_parent is called with child->d_inode->i_sem down
 *    get_name is not (which is possibly inconsistent)
 */

struct export_operations {
	struct dentry *(*decode_fh)(struct super_block *sb, __u32 *fh, int fh_len, int fh_type,
			 int (*acceptable)(void *context, struct dentry *de),
			 void *context);
	int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
			 int connectable);

	/* the following are only called from the filesystem itself */
	int (*get_name)(struct dentry *parent, char *name,
			struct dentry *child);
	struct dentry * (*get_parent)(struct dentry *child);
	struct dentry * (*get_dentry)(struct super_block *sb, void *inump);

	/* This is set by the exporting module to a standard helper */
	struct dentry * (*find_exported_dentry)(
		struct super_block *sb, void *obj, void *parent,
		int (*acceptable)(void *context, struct dentry *de),
		void *context);


};

extern struct dentry *
find_exported_dentry(struct super_block *sb, void *obj, void *parent,
		     int (*acceptable)(void *context, struct dentry *de),
		     void *context);

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

struct super_block *get_sb_bdev(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data,
	int (*fill_super)(struct super_block *, void *, int));
struct super_block *get_sb_single(struct file_system_type *fs_type,
	int flags, void *data,
	int (*fill_super)(struct super_block *, void *, int));
struct super_block *get_sb_nodev(struct file_system_type *fs_type,
	int flags, void *data,
	int (*fill_super)(struct super_block *, void *, int));
void generic_shutdown_super(struct super_block *sb);
void kill_block_super(struct super_block *sb);
void kill_anon_super(struct super_block *sb);
void kill_litter_super(struct super_block *sb);
void deactivate_super(struct super_block *sb);
int set_anon_super(struct super_block *s, void *data);
struct super_block *sget(struct file_system_type *type,
			int (*test)(struct super_block *,void *),
			int (*set)(struct super_block *,void *),
			void *data);
struct super_block *get_sb_pseudo(struct file_system_type *, char *,
			struct super_operations *ops, unsigned long);
int __put_super(struct super_block *sb);
int __put_super_and_need_restart(struct super_block *sb);
void unnamed_dev_init(void);

/* Alas, no aliases. Too much hassle with bringing module.h everywhere */
#define fops_get(fops) \
	(((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
#define fops_put(fops) \
	do { if (fops) module_put((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_tree(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 kstatfs *);

#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;
}

extern int rw_verify_area(int, struct file *, loff_t *, size_t);

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 break_lease(struct inode *inode, unsigned int mode)
{
	if (inode->i_flock)
		return __break_lease(inode, mode);
	return 0;
}

/* fs/open.c */

extern int do_truncate(struct dentry *, loff_t start);
extern long do_sys_open(const char __user *filename, int flags, int mode);
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 __user *);

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

#define __getname()	kmem_cache_alloc(names_cachep, SLAB_KERNEL)
#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
#ifndef CONFIG_AUDITSYSCALL
#define putname(name)   __putname(name)
#else
extern void putname(const char *name);
#endif

extern int register_blkdev(unsigned int, const char *);
extern int unregister_blkdev(unsigned int, const char *);
extern struct block_device *bdget(dev_t);
extern void bd_set_size(struct block_device *, loff_t size);
extern void bd_forget(struct inode *inode);
extern void bdput(struct block_device *);
extern struct block_device *open_by_devnum(dev_t, unsigned);
extern struct file_operations def_blk_fops;
extern struct address_space_operations def_blk_aops;
extern struct file_operations def_chr_fops;
extern struct file_operations bad_sock_fops;
extern struct file_operations def_fifo_fops;
extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
extern int blkdev_ioctl(struct inode *, struct file *, unsigned, unsigned long);
extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
extern int blkdev_get(struct block_device *, mode_t, unsigned);
extern int blkdev_put(struct block_device *);
extern int bd_claim(struct block_device *, void *);
extern void bd_release(struct block_device *);

/* fs/char_dev.c */
extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
extern int register_chrdev_region(dev_t, unsigned, const char *);
extern int register_chrdev(unsigned int, const char *,
			   struct file_operations *);
extern int unregister_chrdev(unsigned int, const char *);
extern void unregister_chrdev_region(dev_t, unsigned);
extern int chrdev_open(struct inode *, struct file *);

/* fs/block_dev.c */
#define BDEVNAME_SIZE	32	/* Largest string for a blockdev identifier */
extern const char *__bdevname(dev_t, char *buffer);
extern const char *bdevname(struct block_device *bdev, char *buffer);
extern struct block_device *lookup_bdev(const char *);
extern struct block_device *open_bdev_excl(const char *, int, void *);
extern void close_bdev_excl(struct block_device *);

extern void init_special_inode(struct inode *, umode_t, dev_t);

/* 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 *);

/*
 * return READ, READA, or WRITE
 */
#define bio_rw(bio)		((bio)->bi_rw & (RW_MASK | RWA_MASK))

/*
 * return data direction, READ or WRITE
 */
#define bio_data_dir(bio)	((bio)->bi_rw & 1)

extern int check_disk_change(struct block_device *);
extern int invalidate_inodes(struct super_block *);
extern int __invalidate_device(struct block_device *);
extern int invalidate_partition(struct gendisk *, int);
unsigned long invalidate_mapping_pages(struct address_space *mapping,
					pgoff_t start, pgoff_t end);
unsigned long invalidate_inode_pages(struct address_space *mapping);
static inline void invalidate_remote_inode(struct inode *inode)
{
	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
	    S_ISLNK(inode->i_mode))
		invalidate_inode_pages(inode->i_mapping);
}
extern int invalidate_inode_pages2(struct address_space *mapping);
extern int invalidate_inode_pages2_range(struct address_space *mapping,
					 pgoff_t start, pgoff_t end);
extern int write_inode_now(struct inode *, int);
extern int filemap_fdatawrite(struct address_space *);
extern int filemap_flush(struct address_space *);
extern int filemap_fdatawait(struct address_space *);
extern int filemap_write_and_wait(struct address_space *mapping);
extern int filemap_write_and_wait_range(struct address_space *mapping,
				        loff_t lstart, loff_t lend);
extern void sync_supers(void);
extern void sync_filesystems(int wait);
extern void emergency_sync(void);
extern void emergency_remount(void);
extern int do_remount_sb(struct super_block *sb, int flags,
			 void *data, int force);
extern sector_t bmap(struct inode *, sector_t);
extern int notify_change(struct dentry *, struct iattr *);
extern int permission(struct inode *, int, struct nameidata *);
extern int generic_permission(struct inode *, int,
		int (*check_acl)(struct inode *, int));

extern int get_write_access(struct inode *);
extern int deny_write_access(struct file *);
static inline void put_write_access(struct inode * inode)
{
	atomic_dec(&inode->i_writecount);
}
static inline void allow_write_access(struct file *file)
{
	if (file)
		atomic_inc(&file->f_dentry->d_inode->i_writecount);
}
extern int do_pipe(int *);

extern int open_namei(const char *, int, int, struct nameidata *);
extern int may_open(struct nameidata *, int, int);