[XFS] Block mount attempts for filesystems with version 1 directories.

SGI Modid: xfs-linux:xfs-kern:21937a

Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Christoph Hellwig <hch@sgi.com>

fs/xfs/xfs_mount.c

@@ -300,6 +300,15 @@ xfs_mount_validate_sb(
 		return XFS_ERROR(EFSCORRUPTED);
 	}
 
+	/*
+	 * Version 1 directory format has never worked on Linux.
+	 */
+	if (unlikely(!XFS_SB_VERSION_HASDIRV2(sbp))) {
+		cmn_err(CE_WARN,
+	"XFS: Attempted to mount file system using version 1 directory format");
+		return XFS_ERROR(ENOSYS);
+	}
+
 	/*
 	 * Until this is fixed only page-sized or smaller data blocks work.
 	 */