From: David Sterba <dsterba@suse.cz>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Liu Bo <bo.li.liu@oracle.com>, Filipe Manana <FdManana@suse.com>,
linux-block <linux-block@vger.kernel.org>
Subject: Re: [PATCH] block: note about cloned bios and bio_for_each_segment_all
Date: Fri, 14 Jul 2017 17:03:13 +0200 [thread overview]
Message-ID: <20170714150313.GJ2866@suse.cz> (raw)
In-Reply-To: <CACVXFVP_a5kofmW-Wfx1FT_kyqFKdatf57RfKLrh+Jte1J8ZmA@mail.gmail.com>
On Fri, Jul 14, 2017 at 09:47:30PM +0800, Ming Lei wrote:
> On Fri, Jul 14, 2017 at 9:40 PM, David Sterba <dsterba@suse.com> wrote:
> > We've switched to cloned bios in btrfs and hit a nasty bug leading to
> > corruptions, when cloned bios are iterated by bio_for_each_segment_all.
>
> No, you simply can't use bio_for_each_segment_all on cloned bio, and the
> reason is obviously.
This was not obvious to us, speaking for the btrfs developers trying to
make more use of the of the bio API, so we had to find out the hard way.
The proposed WARN_ON, possibly more sanity checks or documentation would
help us not to trip over similar problems in the future. I try to take
great care when dealing with code changing bios on our side so I read
the headers, and partially the implementation, but still can miss
something.
next prev parent reply other threads:[~2017-07-14 15:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-14 13:40 [PATCH] block: note about cloned bios and bio_for_each_segment_all David Sterba
2017-07-14 13:47 ` Ming Lei
2017-07-14 14:22 ` Jens Axboe
2017-07-14 20:54 ` Liu Bo
2017-07-14 22:35 ` Ming Lei
2017-07-14 22:37 ` Jens Axboe
2017-07-14 23:20 ` Liu Bo
2017-07-18 22:19 ` Bart Van Assche
2017-07-24 16:19 ` Peter Zijlstra
2017-07-15 0:28 ` David Sterba
2017-07-14 15:03 ` David Sterba [this message]
2017-07-14 17:56 ` Filipe Manana
2017-07-14 18:19 ` 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=20170714150313.GJ2866@suse.cz \
--to=dsterba@suse.cz \
--cc=FdManana@suse.com \
--cc=bo.li.liu@oracle.com \
--cc=linux-block@vger.kernel.org \
--cc=tom.leiming@gmail.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