[PATCH] add /sys/fs

This patch adds an empty /sys/fs, which filesystems can use.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/namespace.c

@@ -48,6 +48,10 @@ static int hash_mask __read_mostly, hash_bits __read_mostly;
 static kmem_cache_t *mnt_cache;
 static struct rw_semaphore namespace_sem;
 
+/* /sys/fs */
+decl_subsys(fs, NULL, NULL);
+EXPORT_SYMBOL_GPL(fs_subsys);
+
 static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
 {
 	unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
@@ -1725,6 +1729,7 @@ void __init mnt_init(unsigned long mempages)
 		i--;
 	} while (i);
 	sysfs_init();
+	subsystem_register(&fs_subsys);
 	init_rootfs();
 	init_mount_tree();
 }

include/linux/fs.h

@@ -1290,6 +1290,9 @@ extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
 
 extern int vfs_statfs(struct super_block *, struct kstatfs *);
 
+/* /sys/fs */
+extern struct subsystem fs_subsys;
+
 #define FLOCK_VERIFY_READ  1
 #define FLOCK_VERIFY_WRITE 2