[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/inode.c b/fs/smbfs/inode.c
index 4a37c2bb..506ff87 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -48,7 +48,7 @@
 
 static void smb_delete_inode(struct inode *);
 static void smb_put_super(struct super_block *);
-static int  smb_statfs(struct super_block *, struct kstatfs *);
+static int  smb_statfs(struct dentry *, struct kstatfs *);
 static int  smb_show_options(struct seq_file *, struct vfsmount *);
 
 static kmem_cache_t *smb_inode_cachep;
@@ -641,13 +641,13 @@
 }
 
 static int
-smb_statfs(struct super_block *sb, struct kstatfs *buf)
+smb_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	int result;
 	
 	lock_kernel();
 
-	result = smb_proc_dskattr(sb, buf);
+	result = smb_proc_dskattr(dentry, buf);
 
 	unlock_kernel();