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| author | Jianchao Wang <jianchao.w.wang@oracle.com> | 2019-01-30 17:01:56 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-01-30 08:53:54 -0700 |
| commit | 85bd6e61f34dffa8ec2dc75ff3c02ee7b2f1cbce (patch) | |
| tree | 62e799a9a8bf88ef4831a9ffc865fd33f3e3f36c | |
| parent | 2e3c18d0ada16f145087b2687afcad1748c0827c (diff) | |
| download | lwn-85bd6e61f34dffa8ec2dc75ff3c02ee7b2f1cbce.tar.gz lwn-85bd6e61f34dffa8ec2dc75ff3c02ee7b2f1cbce.zip | |
blk-mq: fix a hung issue when fsync
Florian reported a io hung issue when fsync(). It should be
triggered by following race condition.
data + post flush a flush
blk_flush_complete_seq
case REQ_FSEQ_DATA
blk_flush_queue_rq
issued to driver blk_mq_dispatch_rq_list
try to issue a flush req
failed due to NON-NCQ command
.queue_rq return BLK_STS_DEV_RESOURCE
request completion
req->end_io // doesn't check RESTART
mq_flush_data_end_io
case REQ_FSEQ_POSTFLUSH
blk_kick_flush
do nothing because previous flush
has not been completed
blk_mq_run_hw_queue
insert rq to hctx->dispatch
due to RESTART is still set, do nothing
To fix this, replace the blk_mq_run_hw_queue in mq_flush_data_end_io
with blk_mq_sched_restart to check and clear the RESTART flag.
Fixes: bd166ef1 (blk-mq-sched: add framework for MQ capable IO schedulers)
Reported-by: Florian Stecker <m19@florianstecker.de>
Tested-by: Florian Stecker <m19@florianstecker.de>
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-flush.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c index a3fc7191c694..6e0f2d97fc6d 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -335,7 +335,7 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error) blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error); spin_unlock_irqrestore(&fq->mq_flush_lock, flags); - blk_mq_run_hw_queue(hctx, true); + blk_mq_sched_restart(hctx); } /** |