From 253f9fd41afe2492b85de779946b5882a00dcdc5 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Fri, 4 Sep 2015 14:14:16 -0700 Subject: [PATCH] raid5-cache: don't delay stripe captured in log There is a case a stripe gets delayed forever. 1. a stripe finishes construction 2. a new bio hits the stripe 3. handle_stripe runs for the stripe. The stripe gets DELAYED bit set since construction can't run for new bio (the stripe is locked since step 1) Without log, handle_stripe will call ops_run_io. After IO finishes, the stripe gets unlocked and the stripe will restart and run construction for the new bio. With log, ops_run_io need to run two times. If the DELAYED bit set, the stripe can't enter into the handle_list, so the second ops_run_io doesn't run, which leaves the stripe stalled. Signed-off-by: Shaohua Li Signed-off-by: NeilBrown --- drivers/md/raid5-cache.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 30c7e5e79a02..0460882a5fd7 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -479,6 +479,11 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) return -EINVAL; set_bit(STRIPE_LOG_TRAPPED, &sh->state); + /* + * The stripe must enter state machine again to finish the write, so + * don't delay. + */ + clear_bit(STRIPE_DELAYED, &sh->state); atomic_inc(&sh->count); mutex_lock(&log->io_mutex);