xfs: fix xfs_reflink_remap_prep calling conventions

Fix the return value of xfs_reflink_remap_prep so that its return value
conventions match the rest of xfs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/xfs_file.c

@@ -1035,7 +1035,7 @@ xfs_file_remap_range(
 	/* Prepare and then clone file data. */
 	ret = xfs_reflink_remap_prep(file_in, pos_in, file_out, pos_out,
 			&len, remap_flags);
-	if (ret < 0 || len == 0)
+	if (ret || len == 0)
 		return ret;
 
 	trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);

fs/xfs/xfs_reflink.c

@@ -1367,7 +1367,7 @@ xfs_reflink_remap_prep(
 	struct inode		*inode_out = file_inode(file_out);
 	struct xfs_inode	*dest = XFS_I(inode_out);
 	bool			same_inode = (inode_in == inode_out);
-	ssize_t			ret;
+	int			ret;
 
 	/* Lock both files against IO */
 	ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out);
@@ -1391,7 +1391,7 @@ xfs_reflink_remap_prep(
 
 	ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
 			len, remap_flags);
-	if (ret < 0 || *len == 0)
+	if (ret || *len == 0)
 		goto out_unlock;
 
 	/* Attach dquots to dest inode before changing block map */
@@ -1426,7 +1426,7 @@ xfs_reflink_remap_prep(
 	if (ret)
 		goto out_unlock;
 
-	return 1;
+	return 0;
 out_unlock:
 	xfs_reflink_remap_unlock(file_in, file_out);
 	return ret;