From: Miao Xie <miaox@cn.fujitsu.com>
To: Chris Mason <clm@fb.com>
Cc: <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH v3 10/11] Btrfs: fix possible deadlock caused by pending I/O in plug list
Date: Thu, 27 Nov 2014 09:39:56 +0800 [thread overview]
Message-ID: <547680EC.7030705@cn.fujitsu.com> (raw)
In-Reply-To: <1417014143.2258.0@mail.thefacebook.com>
On Wed, 26 Nov 2014 10:02:23 -0500, Chris Mason wrote:
> On Wed, Nov 26, 2014 at 8:04 AM, Miao Xie <miaox@cn.fujitsu.com> wrote:
>> The increase/decrease of bio counter is on the I/O path, so we should
>> use io_schedule() instead of schedule(), or the deadlock might be
>> triggered by the pending I/O in the plug list. io_schedule() can help
>> us because it will flush all the pending I/O before the task is going
>> to sleep.
>
> Can you please describe this deadlock in more detail? schedule() also triggers
> a flush of the plug list, and if that's no longer sufficient we can run into other
> problems (especially with preemption on).
Sorry for my miss. I forgot to check the current implementation of schedule(), which flushes the plug list unconditionally. Please ignore this patch.
Thanks
Miao
>
> -chris
>
>
next prev parent reply other threads:[~2014-11-27 1:38 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-14 13:50 [PATCH 0/9] Implement device scrub/replace for RAID56 Miao Xie
2014-11-14 13:50 ` [PATCH 1/9] Btrfs: remove noused bbio_ret in __btrfs_map_block in condition Miao Xie
2014-11-14 14:57 ` David Sterba
2014-11-14 13:50 ` [PATCH 2/9] Btrfs: remove unnecessary code of stripe_index assignment in __btrfs_map_block Miao Xie
2014-11-14 14:55 ` David Sterba
2014-11-14 13:50 ` [PATCH 3/9] Btrfs, raid56: don't change bbio and raid_map Miao Xie
2014-11-14 13:50 ` [PATCH 4/9] Btrfs, scrub: repair the common data on RAID5/6 if it is corrupted Miao Xie
2014-11-24 9:31 ` [PATCH v2 " Miao Xie
2014-11-14 13:50 ` [PATCH 5/9] Btrfs,raid56: use a variant to record the operation type Miao Xie
2014-11-14 13:50 ` [PATCH 6/9] Btrfs,raid56: support parity scrub on raid56 Miao Xie
2014-11-14 13:50 ` [PATCH 7/9] Btrfs, replace: write dirty pages into the replace target device Miao Xie
2014-11-14 13:51 ` [PATCH 8/9] Btrfs, replace: write raid56 parity " Miao Xie
2014-11-14 13:51 ` [PATCH 9/9] Btrfs, replace: enable dev-replace for raid56 Miao Xie
2014-11-14 14:28 ` [PATCH 0/9] Implement device scrub/replace for RAID56 Chris Mason
2014-11-25 15:14 ` Chris Mason
2014-11-26 13:04 ` [PATCH v3 00/11] " Miao Xie
2014-11-26 13:04 ` [PATCH v3 01/11] Btrfs: remove noused bbio_ret in __btrfs_map_block in condition Miao Xie
2014-11-26 13:04 ` [PATCH v3 02/11] Btrfs: remove unnecessary code of stripe_index assignment in __btrfs_map_block Miao Xie
2014-11-26 13:04 ` [PATCH v3 03/11] Btrfs, raid56: don't change bbio and raid_map Miao Xie
2014-11-26 13:04 ` [PATCH v3 04/11] Btrfs, scrub: repair the common data on RAID5/6 if it is corrupted Miao Xie
2014-11-26 13:04 ` [PATCH v3 05/11] Btrfs, raid56: use a variant to record the operation type Miao Xie
2014-11-26 13:04 ` [PATCH v3 06/11] Btrfs, raid56: support parity scrub on raid56 Miao Xie
2014-11-26 13:04 ` [PATCH v3 07/11] Btrfs, replace: write dirty pages into the replace target device Miao Xie
2014-11-26 13:04 ` [PATCH v3 08/11] Btrfs, replace: write raid56 parity " Miao Xie
2014-11-26 13:04 ` [PATCH v3 09/11] Btrfs, raid56: fix use-after-free problem in the final device replace procedure on raid56 Miao Xie
2014-11-26 13:04 ` [PATCH v3 10/11] Btrfs: fix possible deadlock caused by pending I/O in plug list Miao Xie
2014-11-26 15:02 ` Chris Mason
2014-11-27 1:39 ` Miao Xie [this message]
2014-11-27 3:00 ` Miao Xie
2014-11-28 21:32 ` Chris Mason
2014-12-02 13:02 ` Miao Xie
2014-11-26 13:04 ` [PATCH v3 11/11] Btrfs, replace: enable dev-replace for raid56 Miao Xie
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