[PATCH 6.18.y 2/2] xfs: forcibly reset quota timers when upgrading to bigtime during repair

[Sasha Levin <sashal@kernel.org>]

From: "Darrick J. Wong" <djwong@kernel.org>

[ Upstream commit 780212c8d8105eadb5f56b4c7aafb94937755582 ]

If we decide to upgrade a dquot to BIGTIME as part of repairing it, we
should zero out the timer fields so that they are re-evaluated and reset
in bigtime format instead of letting through whatever was in there
before.

Cc: stable@vger.kernel.org # v6.8
Fixes: a5b91555403e3a ("xfs: repair quotas")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Assisted-by: LOLLM # finding obvious bugs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/xfs/scrub/quota_repair.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/scrub/quota_repair.c b/fs/xfs/scrub/quota_repair.c
index cf17d35b70cce..44806ce8c0bf4 100644
--- a/fs/xfs/scrub/quota_repair.c
+++ b/fs/xfs/scrub/quota_repair.c
@@ -348,6 +348,8 @@ xrep_quota_block(
 	bp->b_ops = &xfs_dquot_buf_ops;
 	for (i = 0; i < qi->qi_dqperchunk; i++, dqblk++) {
 		struct xfs_disk_dquot	*ddq = &dqblk->dd_diskdq;
+		bool			was_bigtime =
+				!!(ddq->d_type & XFS_DQTYPE_BIGTIME);
 
 		trace_xrep_disk_dquot(sc->mp, dqtype, id + i);
 
@@ -356,8 +358,21 @@ xrep_quota_block(
 		ddq->d_type = dqtype;
 		ddq->d_id = cpu_to_be32(id + i);
 
-		if (xfs_has_bigtime(sc->mp) && ddq->d_id)
+		if (xfs_has_bigtime(sc->mp) && ddq->d_id) {
+			/*
+			 * If something was broken with this dquot and it was a
+			 * non-bigtime dquot, we'll grant everyone a fresh
+			 * grace period by zeroing the timer field rather than
+			 * try to interpret what might be garbage.
+			 */
+			if (!was_bigtime) {
+				ddq->d_btimer = 0;
+				ddq->d_itimer = 0;
+				ddq->d_rtbtimer = 0;
+			}
+
 			ddq->d_type |= XFS_DQTYPE_BIGTIME;
+		}
 
 		xrep_quota_fix_timer(sc->mp, ddq, ddq->d_blk_softlimit,
 				ddq->d_bcount, &ddq->d_btimer,
-- 
2.53.0