Commit 43e15cdb authored by Al Viro's avatar Al Viro
Browse files

new helper: iterate_supers_type() 



Call the given function for all superblocks of given type.  Function
gets a superblock (with s_umount locked shared) and (void *) argument
supplied by caller of iterator.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 44396f4b

fs/super.c

+36 −0
Original line number Diff line number Diff line
@@ -451,6 +451,42 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg) 
	spin_unlock(&sb_lock);

}



/**

 *	iterate_supers_type - call function for superblocks of given type

 *	@type: fs type

 *	@f: function to call

 *	@arg: argument to pass to it

 *

 *	Scans the superblock list and calls given function, passing it

 *	locked superblock and given argument.

 */

void iterate_supers_type(struct file_system_type *type,

	void (*f)(struct super_block *, void *), void *arg)

{

	struct super_block *sb, *p = NULL;



	spin_lock(&sb_lock);

	list_for_each_entry(sb, &type->fs_supers, s_instances) {

		sb->s_count++;

		spin_unlock(&sb_lock);



		down_read(&sb->s_umount);

		if (sb->s_root)

			f(sb, arg);

		up_read(&sb->s_umount);



		spin_lock(&sb_lock);

		if (p)

			__put_super(p);

		p = sb;

	}

	if (p)

		__put_super(p);

	spin_unlock(&sb_lock);

}



EXPORT_SYMBOL(iterate_supers_type);



/**

 *	get_super - get the superblock of a device

 *	@bdev: device to get the superblock for

include/linux/fs.h

+2 −0
Original line number Diff line number Diff line
@@ -2432,6 +2432,8 @@ extern struct super_block *get_active_super(struct block_device *bdev); 
extern struct super_block *user_get_super(dev_t);

extern void drop_super(struct super_block *sb);

extern void iterate_supers(void (*)(struct super_block *, void *), void *);

extern void iterate_supers_type(struct file_system_type *,

			        void (*)(struct super_block *, void *), void *);



extern int dcache_dir_open(struct inode *, struct file *);

extern int dcache_dir_close(struct inode *, struct file *);