xfs: replace on-stack xfs_trans_res with pointer in xfs_create()

There's no need to store a full struct xfs_trans_res on the stack in
xfs_create() and copy the fields. Use a pointer to the appropriate
structures embedded in the xfs_mount.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_inode.c

@@ -1082,7 +1082,7 @@ xfs_create(
 	struct xfs_dquot	*udqp = NULL;
 	struct xfs_dquot	*gdqp = NULL;
 	struct xfs_dquot	*pdqp = NULL;
-	struct xfs_trans_res	tres;
+	struct xfs_trans_res	*tres;
 	uint			resblks;
 
 	trace_xfs_create(dp, name);
@@ -1105,13 +1105,11 @@ xfs_create(
 	if (is_dir) {
 		rdev = 0;
 		resblks = XFS_MKDIR_SPACE_RES(mp, name->len);
-		tres.tr_logres = M_RES(mp)->tr_mkdir.tr_logres;
-		tres.tr_logcount = XFS_MKDIR_LOG_COUNT;
+		tres = &M_RES(mp)->tr_mkdir;
 		tp = xfs_trans_alloc(mp, XFS_TRANS_MKDIR);
 	} else {
 		resblks = XFS_CREATE_SPACE_RES(mp, name->len);
-		tres.tr_logres = M_RES(mp)->tr_create.tr_logres;
-		tres.tr_logcount = XFS_CREATE_LOG_COUNT;
+		tres = &M_RES(mp)->tr_create;
 		tp = xfs_trans_alloc(mp, XFS_TRANS_CREATE);
 	}
 
@@ -1123,17 +1121,16 @@ xfs_create(
 	 * the case we'll drop the one we have and get a more
 	 * appropriate transaction later.
 	 */
-	tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
-	error = xfs_trans_reserve(tp, &tres, resblks, 0);
+	error = xfs_trans_reserve(tp, tres, resblks, 0);
 	if (error == -ENOSPC) {
 		/* flush outstanding delalloc blocks and retry */
 		xfs_flush_inodes(mp);
-		error = xfs_trans_reserve(tp, &tres, resblks, 0);
+		error = xfs_trans_reserve(tp, tres, resblks, 0);
 	}
 	if (error == -ENOSPC) {
 		/* No space at all so try a "no-allocation" reservation */
 		resblks = 0;
-		error = xfs_trans_reserve(tp, &tres, 0, 0);
+		error = xfs_trans_reserve(tp, tres, 0, 0);
 	}
 	if (error) {
 		cancel_flags = 0;