[XFS] kill xfs_root

The only caller (xfs_fs_fill_super) can simplify call igrab on the root
inode.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30393a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 49d1d0e..56b6c69 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1344,9 +1344,11 @@
 	sb->s_time_gran = 1;
 	set_posix_acl_flag(sb);
 
-	error = xfs_root(mp, &rootvp);
-	if (error)
+	rootvp = igrab(mp->m_rootip->i_vnode);
+	if (!rootvp) {
+		error = ENOENT;
 		goto fail_unmount;
+	}
 
 	sb->s_root = d_alloc_root(vn_to_inode(rootvp));
 	if (!sb->s_root) {