dm-integrity: fix a typo in the code for write/discard race

[ Upstream commit c698b7f ]

If we send a write followed by a discard, it may be possible that the
discarded data end up being overwritten by the previous write from the
journal. The code tries to prevent that, but there was a typo in this
logic that made it not being activated as it should be.

Note that if we end up here the second time (when discard_retried is
true), it means that the write bio is actually racing with the discard
bio, and in this situation it is not specified which of them should win.

Cc: stable@vger.kernel.org
Fixes: 31843ed ("dm integrity: improve discard in journal mode")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Mikulas Patocka

drivers/md/dm-integrity.c

@@ -2298,7 +2298,7 @@ static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map
 		sector_t next_sector;
 		unsigned int new_pos = find_journal_node(ic, dio->range.logical_sector, &next_sector);
 		if (unlikely(new_pos != NOT_FOUND) ||
-		    unlikely(next_sector < dio->range.logical_sector - dio->range.n_sectors)) {
+		    unlikely(next_sector < dio->range.logical_sector + dio->range.n_sectors)) {
 			remove_range_unlocked(ic, &dio->range);
 			spin_unlock_irq(&ic->endio_wait.lock);
 			queue_work(ic->commit_wq, &ic->commit_work);