From: Darrick J. Wong <djwong@xxxxxxxxxx>
Committing a transaction tx0 with a defer ops chain of (A, B, C)
creates a chain of transactions that looks like this:
tx0 -> txA -> txB -> txC
Prior to commit cb042117488dbf, __xfs_trans_commit would run precommits
on tx0, then call xfs_defer_finish_noroll to convert A-C to tx[A-C].
Unfortunately, after the finish_noroll loop we forgot to run precommits
on txC. That was fixed by adding the second precommit call.
Unfortunately, none of us remembered that xfs_defer_finish_noroll
calls __xfs_trans_commit a second time to commit tx0 before finishing
work A in txA and committing that. In other words, we run precommits
twice on tx0:
xfs_trans_commit(tx0)
__xfs_trans_commit(tx0, false)
xfs_trans_run_precommits(tx0)
xfs_defer_finish_noroll(tx0)
xfs_trans_roll(tx0)
txA = xfs_trans_dup(tx0)
__xfs_trans_commit(tx0, true)
xfs_trans_run_precommits(tx0)
This currently isn't an issue because the inode item precommit is
idempotent; the iunlink item precommit deletes itself so it can't be
called again; and the buffer/dquot item precommits only check the incore
objects for corruption. However, it doesn't make sense to run
precommits twice.
Fix this situation by only running precommits after finish_noroll.
Cc: <stable@xxxxxxxxxxxxxxx> # v6.4
Fixes: cb042117488dbf ("xfs: defered work could create precommits")
Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
fs/xfs/xfs_trans.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 05b18e30368e4b..4a517250efc911 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -860,13 +860,6 @@ __xfs_trans_commit(
trace_xfs_trans_commit(tp, _RET_IP_);
- error = xfs_trans_run_precommits(tp);
- if (error) {
- if (tp->t_flags & XFS_TRANS_PERM_LOG_RES)
- xfs_defer_cancel(tp);
- goto out_unreserve;
- }
-
/*
* Finish deferred items on final commit. Only permanent transactions
* should ever have deferred ops.
@@ -877,13 +870,12 @@ __xfs_trans_commit(
error = xfs_defer_finish_noroll(&tp);
if (error)
goto out_unreserve;
-
- /* Run precommits from final tx in defer chain. */
- error = xfs_trans_run_precommits(tp);
- if (error)
- goto out_unreserve;
}
+ error = xfs_trans_run_precommits(tp);
+ if (error)
+ goto out_unreserve;
+
/*
* If there is nothing to be logged by the transaction,
* then unlock all of the items associated with the
