From: Jens Axboe <axboe@kernel.dk>
To: edwardh <edwardh@synology.com>, neilb@suse.com, hch@infradead.org
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
s3t@synology.com, bingjingc@synology.com, cccheng@synology.com,
Wade Liang <wadel@synology.com>
Subject: Re: [PATCH v4] block: fix trace completion for chained bio
Date: Thu, 24 Jun 2021 09:54:12 -0600 [thread overview]
Message-ID: <ff63b647-0c0b-e7c7-0daf-499dc358e0dd@kernel.dk> (raw)
In-Reply-To: <20210624123030.27014-1-edwardh@synology.com>
On 6/24/21 6:30 AM, edwardh wrote:
> From: Edward Hsieh <edwardh@synology.com>
>
> For chained bio, trace_block_bio_complete in bio_endio is currently called
> only by the parent bio once upon all chained bio completed.
> However, the sector and size for the parent bio are modified in bio_split.
> Therefore, the size and sector of the complete events might not match the
> queue events in blktrace.
>
> The original fix of bio completion trace <fbbaf700e7b1> ("block: trace
> completion of all bios.") wants multiple complete events to correspond
> to one queue event but missed this.
>
> The issue can be reproduced by md/raid5 read with bio cross chunks.
>
> To fix, move trace completion into the loop for every chained bio to call.
Applied, thanks.
--
Jens Axboe
prev parent reply other threads:[~2021-06-24 15:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-24 12:30 [PATCH v4] block: fix trace completion for chained bio edwardh
2021-06-24 12:40 ` Christoph Hellwig
2021-06-24 15:54 ` Jens Axboe [this message]
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