xfs: Fix file type directory corruption for btree directories

Users have occasionally reported that file type for some directory
entries is wrong. This mostly happened after updating libraries some
libraries. After some debugging the problem was traced down to
xfs_dir2_node_replace(). The function uses args->filetype as a file type
to store in the replaced directory entry however it also calls
xfs_da3_node_lookup_int() which will store file type of the current
directory entry in args->filetype. Thus we fail to change file type of a
directory entry to a proper type.

Fix the problem by storing new file type in a local variable before
calling xfs_da3_node_lookup_int().

cc: <stable@vger.kernel.org> # 3.16 - 4.x
Reported-by: Giacomo Comes <comes@naic.edu>
Signed-off-by: Jan Kara <jack@suse.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_dir2_node.c

@@ -2132,6 +2132,7 @@ xfs_dir2_node_replace(
 	int			error;		/* error return value */
 	int			i;		/* btree level */
 	xfs_ino_t		inum;		/* new inode number */
+	int			ftype;		/* new file type */
 	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
 	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry being changed */
 	int			rval;		/* internal return value */
@@ -2145,7 +2146,14 @@ xfs_dir2_node_replace(
 	state = xfs_da_state_alloc();
 	state->args = args;
 	state->mp = args->dp->i_mount;
+
+	/*
+	 * We have to save new inode number and ftype since
+	 * xfs_da3_node_lookup_int() is going to overwrite them
+	 */
 	inum = args->inumber;
+	ftype = args->filetype;
+
 	/*
 	 * Lookup the entry to change in the btree.
 	 */
@@ -2183,7 +2191,7 @@ xfs_dir2_node_replace(
 		 * Fill in the new inode number and log the entry.
 		 */
 		dep->inumber = cpu_to_be64(inum);
-		args->dp->d_ops->data_put_ftype(dep, args->filetype);
+		args->dp->d_ops->data_put_ftype(dep, ftype);
 		xfs_dir2_data_log_entry(args, state->extrablk.bp, dep);
 		rval = 0;
 	}