Hi, On Fri, Aug 24, 2018 at 04:20:41PM -0600, Jens Axboe wrote: > Hi, > > Was testing other things today, but ended up with this: > > # echo "write through" > /sys/block/sde/device/scsi_disk/4:0:0:0/cache_type > > hanging. Looking closer, the request is successfully queued and the > caller is waiting on rq execution and completion, but the request is > sitting in the hctx->dispatch list and is continually being attempted > issued, but gets a BLK_STS_RESOURCE return. Just run fio randwrite and 'dbench -s' on virtio-scsi/usb-storage after setting 'write through', looks not see such issue. Also not see such kind of issue on blktests/xfstests against today's next tree too. Could you share a bit more(disk, io sched, dmesg log, workload) about how to reproduce it? Is it in normal IO path or EH? Thanks, Ming