[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, 1 insertions, 1 deletions

diff --git a/fs/super.c b/fs/super.c
index 324c2d232f54..057b5325b7ef 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -486,7 +486,7 @@ asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf)
         s = user_get_super(new_decode_dev(dev));
         if (s == NULL)
                 goto out;
-        err = vfs_statfs(s, &sbuf);
+        err = vfs_statfs(s->s_root, &sbuf);
         drop_super(s);
         if (err)
                 goto out;