writecache_bio_copy_ssd sets wc->uncommitted_blocks = 0; and then queues the flush work: queue_work(wc->writeback_wq, &wc->flush_work);
It may be possible that discard is dispatched in this window, and the discard would decrement wc->uncommitted_blocks to -1U. Note that this bug is benign - wc->uncommitted_blocks is only used to trigged autocommit, so decrementing it to -1U will trigger a spurious autocommit, but won't cause any data corruption. Signed-off-by: Mikulas Patocka <[email protected]> Assisted-by: Claude:claude-opus-5 --- drivers/md/dm-writecache.c | 2 -- 1 file changed, 2 deletions(-) Index: linux-2.6/drivers/md/dm-writecache.c =================================================================== --- linux-2.6.orig/drivers/md/dm-writecache.c +++ linux-2.6/drivers/md/dm-writecache.c @@ -899,8 +899,6 @@ static void writecache_discard(struct dm } discarded_something = true; } - if (!writecache_entry_is_committed(wc, e)) - wc->uncommitted_blocks--; writecache_free_entry(wc, e); }
