From: Andrew Morton <akpm@linux-foundation.org>
To: Paul Clements <paul.clements@steeleye.com>
Cc: linux-kernel@vger.kernel.org,
jnelson-kernel-bugzilla@jamponi.net, Pavel Machek <pavel@ucw.cz>,
stable@kernel.org
Subject: Re: [PATCH 1/1] NBD: fix I/O hang on disconnected nbds
Date: Tue, 10 Feb 2009 13:35:37 -0800 [thread overview]
Message-ID: <20090210133537.23b1779a.akpm@linux-foundation.org> (raw)
In-Reply-To: <4990743F.1070409@steeleye.com>
On Mon, 09 Feb 2009 13:21:51 -0500
Paul Clements <paul.clements@steeleye.com> wrote:
> This patch fixes a problem that causes I/O to a disconnected
> (or partially initialized) nbd device to hang indefinitely. To reproduce:
>
> # ioctl NBD_SET_SIZE_BLOCKS /dev/nbd23 514048
> # dd if=/dev/nbd23 of=/dev/null bs=4096 count=1
>
> ...hangs...
>
> This can also occur when an nbd device loses its nbd-client/server
> connection. Although we clear the queue of any outstanding I/Os after
> the client/server connection fails, any additional I/Os that get queued
> later will hang.
>
> This bug may also be the problem reported in this bug report:
> http://bugzilla.kernel.org/show_bug.cgi?id=12277
>
> Testing would need to be performed to determine if the two issues are
> the same.
>
> This problem was introduced by the new request handling thread code
> ("NBD: allow nbd to be used locally", 3/2008), which entered into
> mainline around 2.6.25.
Seems that the patch applies to 2.6.26, but not to 2.6.25.
>
> The fix, which is fairly simple, is to restore the check for lo->sock
> being NULL in do_nbd_request. This causes I/O to an uninitialized nbd to
> immediately fail with an I/O error, as it did prior to the introduction
> of this bug.
I marked this as needing backporting into 2.6.26.x, 2.6.27.x and
2.6.28.x. OK?
next prev parent reply other threads:[~2009-02-10 21:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-09 18:21 Paul Clements
2009-02-10 21:35 ` Andrew Morton [this message]
2009-02-10 21:53 ` Paul Clements
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=20090210133537.23b1779a.akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=jnelson-kernel-bugzilla@jamponi.net \
--cc=linux-kernel@vger.kernel.org \
--cc=paul.clements@steeleye.com \
--cc=pavel@ucw.cz \
--cc=stable@kernel.org \
/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
Powered by JetHome