From: Christoph Hellwig <email@example.com> To: Ming Lei <firstname.lastname@example.org> Cc: Christoph Hellwig <email@example.com>, Jens Axboe <firstname.lastname@example.org>, Tejun Heo <email@example.com>, firstname.lastname@example.org Subject: Re: [PATCH 3/4] block: drain file system I/O on del_gendisk Date: Mon, 27 Sep 2021 14:04:41 +0200 [thread overview] Message-ID: <20210927120441.GA25223@lst.de> (raw) In-Reply-To: <YUwhPy1J8lzHQF77@T590> On Thu, Sep 23, 2021 at 02:39:59PM +0800, Ming Lei wrote: > > > After blk_mq_unfreeze_queue() returns, blk_try_enter_queue() will return > > > true, so new FS I/O from opened bdev still won't be blocked, right? > > > > It won't be blocked by blk_mq_unfreeze_queue, but because the capacity > > is set to 0 it still won't make it to the driver. > > One bio could be made & checked before set_capacity(0), then is > submitted after blk_mq_unfreeze_queue() returns. > > blk_mq_freeze_queue_wait() doesn't always imply RCU grace period, for > example, the .q_usage_counter may have been in atomic mode before > calling blk_queue_start_drain() & blk_mq_freeze_queue_wait(). True, but this isn't really a new issue as we never had proper quiesce behavior. I have a bunch of ideas of how to make this actually solid, but none of them looks like 5.15 material.
next prev parent reply other threads:[~2021-09-27 12:14 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-22 17:22 tear down file system I/O in del_gendisk v2 Christoph Hellwig 2021-09-22 17:22 ` [PATCH 1/4] block: factor out a blk_try_enter_queue helper Christoph Hellwig 2021-09-22 17:22 ` [PATCH 2/4] block: split bio_queue_enter from blk_queue_enter Christoph Hellwig 2021-09-22 17:22 ` [PATCH 3/4] block: drain file system I/O on del_gendisk Christoph Hellwig 2021-09-23 1:34 ` Ming Lei 2021-09-23 5:27 ` Christoph Hellwig 2021-09-23 6:39 ` Ming Lei 2021-09-27 12:04 ` Christoph Hellwig [this message] 2021-09-27 14:32 ` Ming Lei 2021-09-23 6:21 ` Hannes Reinecke 2021-09-22 17:22 ` [PATCH 4/4] block: keep q_usage_counter in atomic mode after del_gendisk Christoph Hellwig -- strict thread matches above, loose matches on Subject: below -- 2021-09-20 11:24 tear down file system I/O in del_gendisk Christoph Hellwig 2021-09-20 11:24 ` [PATCH 3/4] block: drain file system I/O on del_gendisk Christoph Hellwig
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