From: Brian Foster <bfoster@redhat.com>
Date: Fri, 5 Oct 2018 02:36:11 +0000 (-0500)
Subject: xfs: refactor internal dfops initialization
X-Git-Tag: v4.19.0-rc0~16
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3645e8edb3b194fb7c7ea9e329018ffe98f9609a;p=thirdparty%2Fxfsprogs-dev.git

xfs: refactor internal dfops initialization

Source kernel commit: 98719051e75ccf9eca18bd2b569de4ea637b4479

The current transaction allocation code conditionally initializes
the ->t_dfops indirection pointer. Transaction commit/cancel check
the validity of the pointer to determine whether to finish/cancel
the internal dfops.

This disallows the ability to use the internal dfops list as a
temporary container (via xfs_trans_alloc_empty()). Refactor
transaction allocation to always initialize ->t_dfops and check
permanent reservation state on transaction commit/cancel.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
---

diff --git a/libxfs/trans.c b/libxfs/trans.c
index bda2d8c68..3221a3f52 100644
--- a/libxfs/trans.c
+++ b/libxfs/trans.c
@@ -274,13 +274,7 @@ libxfs_trans_alloc(
 	INIT_LIST_HEAD(&tp->t_items);
 	tp->t_firstblock = NULLFSBLOCK;
 
-	/*
-	 * We only roll transactions with permanent log reservation. Don't init
-	 * ->t_dfops to skip attempts to finish or cancel an empty dfops with a
-	 * non-permanent res.
-	 */
-	if (resp->tr_logflags & XFS_TRANS_PERM_LOG_RES)
-		xfs_defer_init(tp, &tp->t_dfops_internal);
+	xfs_defer_init(tp, &tp->t_dfops_internal);
 
 	error = xfs_trans_reserve(tp, resp, blocks, rtextents);
 	if (error) {
@@ -341,7 +335,7 @@ libxfs_trans_cancel(
 	if (tp == NULL)
 		goto out;
 
-	if (tp->t_dfops)
+	if (tp->t_flags & XFS_TRANS_PERM_LOG_RES)
 		xfs_defer_cancel(tp);
 
 	xfs_trans_free_items(tp);
@@ -1002,8 +996,13 @@ __xfs_trans_commit(
 	if (tp == NULL)
 		return 0;
 
-	/* finish deferred items on final commit */
-	if (!regrant && tp->t_dfops) {
+	/*
+	 * Finish deferred items on final commit. Only permanent transactions
+	 * should ever have deferred ops.
+	 */
+	WARN_ON_ONCE(xfs_defer_has_unfinished_work(tp->t_dfops) &&
+		     !(tp->t_flags & XFS_TRANS_PERM_LOG_RES));
+	if (!regrant && (tp->t_flags & XFS_TRANS_PERM_LOG_RES)) {
 		error = xfs_defer_finish_noroll(&tp);
 		if (error) {
 			xfs_defer_cancel(tp);