[PATCH 6.6 CANDIDATE 2/4] xfs: don't lose solo superblock counter update transactions

From: "Darrick J. Wong" <[email protected]>

commit 3762113b597fa600d4e03300eec048256c546b1c upstream.

Superblock counter updates are tracked via per-transaction counters in
the xfs_trans object.  These changes are then turned into dirty log
items in xfs_trans_apply_sb_deltas just prior to commiting the log items
to the CIL.

However, updating the per-transaction counter deltas do not cause
XFS_TRANS_DIRTY to be set on the transaction.  In other words, a pure sb
counter update will be silently discarded if there are no other dirty
log items attached to the transaction.

This is currently not the case anywhere in the filesystem because sb
counter updates always dirty at least one other metadata item, but let's
not leave a logic bomb.

Signed-off-by: "Darrick J. Wong" <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Catherine Hoang <[email protected]>
---
 fs/xfs/xfs_trans.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index c5bc429b6b75..dec01d63ef44 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -955,6 +955,13 @@ __xfs_trans_commit(
 
 	trace_xfs_trans_commit(tp, _RET_IP_);
 
+	/*
+	 * Commit per-transaction changes that are not already tracked through
+	 * log items.  This can add dirty log items to the transaction.
+	 */
+	if (tp->t_flags & XFS_TRANS_SB_DIRTY)
+		xfs_trans_apply_sb_deltas(tp);
+
 	error = xfs_trans_run_precommits(tp);
 	if (error)
 		goto out_unreserve;
@@ -985,8 +992,6 @@ __xfs_trans_commit(
 	/*
 	 * If we need to update the superblock, then do it now.
 	 */
-	if (tp->t_flags & XFS_TRANS_SB_DIRTY)
-		xfs_trans_apply_sb_deltas(tp);
 	xfs_trans_apply_dquot_deltas(tp);
 
 	xlog_cil_commit(log, tp, &commit_seq, regrant);
-- 
2.39.3