From: Christoph Hellwig <hch@infradead.org>
To: edwardh <edwardh@synology.com>
Cc: axboe@kernel.dk, neilb@suse.com, hch@infradead.org,
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 13:40:03 +0100 [thread overview]
Message-ID: <YNR9I7zsCJ8s0Drh@infradead.org> (raw)
In-Reply-To: <20210624123030.27014-1-edwardh@synology.com>
On Thu, Jun 24, 2021 at 08:30:30PM +0800, 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.
>
> Fixes: fbbaf700e7b1 ("block: trace completion of all bios.")
> Reviewed-by: Wade Liang <wadel@synology.com>
> Reviewed-by: BingJing Chang <bingjingc@synology.com>
> Signed-off-by: Edward Hsieh <edwardh@synology.com>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2021-06-24 12:41 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 [this message]
2021-06-24 15:54 ` Jens Axboe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YNR9I7zsCJ8s0Drh@infradead.org \
--to=hch@infradead.org \
--cc=axboe@kernel.dk \
--cc=bingjingc@synology.com \
--cc=cccheng@synology.com \
--cc=edwardh@synology.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=neilb@suse.com \
--cc=s3t@synology.com \
--cc=wadel@synology.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).