| Message ID | 20220122111054.1126146-5-ming.lei@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | block: don't drain file system I/O on del_gendisk | expand |
Jens, can you pick this up for the block-5.17 tree? On Sat, Jan 22, 2022 at 07:10:45PM +0800, Ming Lei wrote: > From: Laibin Qiu <qiulaibin@huawei.com> > > Now that we disable wbt by set WBT_STATE_OFF_DEFAULT in > wbt_disable_default() when switch elevator to bfq. And when > we remove scsi device, wbt will be enabled by wbt_enable_default. > If it become false positive between wbt_wait() and wbt_track() > when submit write request. > > The following is the scenario that triggered the problem. > > T1 T2 T3 > elevator_switch_mq > bfq_init_queue > wbt_disable_default <= Set > rwb->enable_state (OFF) > Submit_bio > blk_mq_make_request > rq_qos_throttle > <= rwb->enable_state (OFF) > scsi_remove_device > sd_remove > del_gendisk > blk_unregister_queue > elv_unregister_queue > wbt_enable_default > <= Set rwb->enable_state (ON) > q_qos_track > <= rwb->enable_state (ON) > ^^^^^^ this request will mark WBT_TRACKED without inflight add and will > lead to drop rqw->inflight to -1 in wbt_done() which will trigger IO hung. > > Fix this by move wbt_enable_default() from elv_unregister to > bfq_exit_queue(). Only re-enable wbt when bfq exit. > > Fixes: 76a8040817b4b ("blk-wbt: make sure throttle is enabled properly") > > Remove oneline stale comment, and kill one oneshot local variable. > > Signed-off-by: Ming Lei <ming.lei@rehdat.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Link: https://lore.kernel.org/linux-block/20211214133103.551813-1-qiulaibin@huawei.com/ > Signed-off-by: Laibin Qiu <qiulaibin@huawei.com> > --- > block/bfq-iosched.c | 2 ++ > block/elevator.c | 2 -- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c > index 0c612a911696..36a66e97e3c2 100644 > --- a/block/bfq-iosched.c > +++ b/block/bfq-iosched.c > @@ -7018,6 +7018,8 @@ static void bfq_exit_queue(struct elevator_queue *e) > spin_unlock_irq(&bfqd->lock); > #endif > > + wbt_enable_default(bfqd->queue); > + > kfree(bfqd); > } > > diff --git a/block/elevator.c b/block/elevator.c > index ec98aed39c4f..482df2a350fc 100644 > --- a/block/elevator.c > +++ b/block/elevator.c > @@ -525,8 +525,6 @@ void elv_unregister_queue(struct request_queue *q) > kobject_del(&e->kobj); > > e->registered = 0; > - /* Re-enable throttling in case elevator disabled it */ > - wbt_enable_default(q); > } > } > > -- > 2.31.1 ---end quoted text---
On 2/17/22 12:45 AM, Christoph Hellwig wrote:
> Jens, can you pick this up for the block-5.17 tree?
Done
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 0c612a911696..36a66e97e3c2 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -7018,6 +7018,8 @@ static void bfq_exit_queue(struct elevator_queue *e) spin_unlock_irq(&bfqd->lock); #endif + wbt_enable_default(bfqd->queue); + kfree(bfqd); } diff --git a/block/elevator.c b/block/elevator.c index ec98aed39c4f..482df2a350fc 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -525,8 +525,6 @@ void elv_unregister_queue(struct request_queue *q) kobject_del(&e->kobj); e->registered = 0; - /* Re-enable throttling in case elevator disabled it */ - wbt_enable_default(q); } }