[PATCH] VFS: Permit filesystem to perform statfs with a known root dentry

Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.

This complements the get_sb() patch.  That reduced the significance of
sb->s_root, allowing NFS to place a fake root there.  However, NFS does
require a dentry to use as a target for the statfs operation.  This permits
the root in the vfsmount to be used instead.

linux/mount.h has been added where necessary to make allyesconfig build
successfully.

Interest has also been expressed for use with the FUSE and XFS filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index e7da03f63a5a..cf74f3d4d966 100644
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -203,8 +203,9 @@ static void bfs_put_super(struct super_block *s)
         s->s_fs_info = NULL;
 }
 
-static int bfs_statfs(struct super_block *s, struct kstatfs *buf)
+static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
+        struct super_block *s = dentry->d_sb;
         struct bfs_sb_info *info = BFS_SB(s);
         u64 id = huge_encode_dev(s->s_bdev->bd_dev);
         buf->f_type = BFS_MAGIC;