fs.h

Axis 221 camera embedded programing interface

 * read, write, poll, fsync, readv, writev, unlocked_ioctl and compat_ioctl
 * 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 __user *, size_t, loff_t *);
	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
	ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
	ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, 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);
	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
	int (*mmap) (struct file *, struct vm_area_struct *);
	int (*open) (struct inode *, struct file *);
	int (*flush) (struct file *, fl_owner_t id);
	int (*release) (struct inode *, struct file *);
	int (*fsync) (struct file *, struct dentry *, int datasync);
	int (*aio_fsync) (struct kiocb *, int datasync);
	int (*fasync) (int, struct file *, int);
	int (*lock) (struct file *, int, struct file_lock *);
	ssize_t (*sendfile) (struct file *, loff_t *, size_t, read_actor_t, void *);
	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 (*check_flags)(int);
	int (*dir_notify)(struct file *filp, unsigned long arg);
	int (*flock) (struct file *, int, struct file_lock *);
	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
	ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
};

struct inode_operations {
	int (*create) (struct inode *,struct dentry *,int, struct nameidata *);
	struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameidata *);
	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,dev_t);
	int (*rename) (struct inode *, struct dentry *,
			struct inode *, struct dentry *);
	int (*readlink) (struct dentry *, char __user *,int);
	void * (*follow_link) (struct dentry *, struct nameidata *);
	void (*put_link) (struct dentry *, struct nameidata *, void *);
	void (*truncate) (struct inode *);
	int (*permission) (struct inode *, int, struct nameidata *);
	int (*setattr) (struct dentry *, struct iattr *);
	int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
	int (*setxattr) (struct dentry *, const char *,const 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 *);
	void (*truncate_range)(struct inode *, loff_t, loff_t);
};

struct seq_file;

ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
				unsigned long nr_segs, unsigned long fast_segs,
				struct iovec *fast_pointer,
				struct iovec **ret_pointer);

extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
		unsigned long, loff_t *);
extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
		unsigned long, loff_t *);

/*
 * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
 * without the big kernel lock held in all filesystems.
 */
struct super_operations {
   	struct inode *(*alloc_inode)(struct super_block *sb);
	void (*destroy_inode)(struct inode *);

	void (*read_inode) (struct inode *);
  
   	void (*dirty_inode) (struct inode *);
	int (*write_inode) (struct inode *, int);
	void (*put_inode) (struct inode *);
	void (*drop_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 *sb, int wait);
	void (*write_super_lockfs) (struct super_block *);
	void (*unlockfs) (struct super_block *);
	int (*statfs) (struct dentry *, struct kstatfs *);
	int (*remount_fs) (struct super_block *, int *, char *);
	void (*clear_inode) (struct inode *);
	void (*umount_begin) (struct vfsmount *, int);

	int (*show_options)(struct seq_file *, struct vfsmount *);
	int (*show_stats)(struct seq_file *, struct vfsmount *);
#ifdef CONFIG_QUOTA
	ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
	ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
#endif
};

/* Inode state bits.  Protected by inode_lock. */
#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		3
#define I_LOCK			(1 << __I_LOCK)
#define I_FREEING		16
#define I_CLEAR			32
#define I_NEW			64
#define I_WILL_FREE		128

#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 inc_nlink(struct inode *inode)
{
	inode->i_nlink++;
}

static inline void inode_inc_link_count(struct inode *inode)
{
	inc_nlink(inode);
	mark_inode_dirty(inode);
}

static inline void drop_nlink(struct inode *inode)
{
	inode->i_nlink--;
}

static inline void clear_nlink(struct inode *inode)
{
	inode->i_nlink = 0;
}

static inline void inode_dec_link_count(struct inode *inode)
{
	drop_nlink(inode);
	mark_inode_dirty(inode);
}

extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry);
static inline void file_accessed(struct file *file)
{
	if (!(file->f_flags & O_NOATIME))
		touch_atime(file->f_path.mnt, file->f_path.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
 * @find_exported_dentry:
 *	set by the exporting module to a standard helper function.
 *
 * 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_mutex 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_mutex 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;
	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 list_head fs_supers;
	struct lock_class_key s_lock_key;
	struct lock_class_key s_umount_key;
};

extern int 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 vfsmount *mnt);
extern int get_sb_single(struct file_system_type *fs_type,
	int flags, void *data,
	int (*fill_super)(struct super_block *, void *, int),
	struct vfsmount *mnt);
extern int get_sb_nodev(struct file_system_type *fs_type,
	int flags, void *data,
	int (*fill_super)(struct super_block *, void *, int),
	struct vfsmount *mnt);
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);
extern int get_sb_pseudo(struct file_system_type *, char *,
	struct super_operations *ops, unsigned long,
	struct vfsmount *mnt);
extern int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb);
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 void umount_tree(struct vfsmount *, int, struct list_head *);
extern void release_mounts(struct list_head *);
extern long do_mount(char *, char *, char *, unsigned long, void *);
extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int);
extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
				  struct vfsmount *);

extern int vfs_statfs(struct dentry *, struct kstatfs *);

/* /sys/fs */
extern struct subsystem fs_subsys;

#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)