[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>
diff --git a/fs/smbfs/proc.c b/fs/smbfs/proc.c
index b1b878b..c349505 100644
--- a/fs/smbfs/proc.c
+++ b/fs/smbfs/proc.c
@@ -3226,9 +3226,9 @@
 }
 
 int
-smb_proc_dskattr(struct super_block *sb, struct kstatfs *attr)
+smb_proc_dskattr(struct dentry *dentry, struct kstatfs *attr)
 {
-	struct smb_sb_info *server = SMB_SB(sb);
+	struct smb_sb_info *server = SMB_SB(dentry->d_sb);
 	int result;
 	char *p;
 	long unit;