From: Mark Tinguely <tinguely@sgi.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 3/3] xfs: drop buffer io reference when a bad bio is built
Date: Mon, 12 Nov 2012 14:51:43 -0600 [thread overview]
Message-ID: <50A1615F.10809@sgi.com> (raw)
In-Reply-To: <1352718586-3538-4-git-send-email-david@fromorbit.com>
On 11/12/12 05:09, Dave Chinner wrote:
> From: Dave Chinner<dchinner@redhat.com>
>
> Error handling in xfs_buf_ioapply_map() does not handle IO reference
> counts correctly. We increment the b_io_remaining count before
> building the bio, but then fail to decrement it in the failure case.
> This leads to the buffer never running IO completion and releasing
> the reference that the IO holds, so at unmount we can leak the
> buffer. This leak is captured by this assert failure during unmount:
>
> XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0, file: fs/xfs/xfs_mount.c, line: 273
>
> This is not a new bug - the b_io_remaining accounting has had this
> problem for a long, long time - it's just very hard to get a
> zero length bio being built by this code...
>
> Further, the buffer IO error can be overwritten on a multi-segment
> buffer by subsequent bio completions for partial sections of the
> buffer. Hence we should only set the buffer error status if the
> buffer is not already carrying an error status. This ensures that a
> partial IO error on a multi-segment buffer will not be lost. This
> part of the problem is a regression, however.
>
> cc:<stable@vger.kernel.org>
> Signed-off-by: Dave Chinner<dchinner@redhat.com>
> ---
Looks good.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2012-11-12 20:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-12 11:09 [PATCH 0/3] xfs: fixes for 3.7-rc6 Dave Chinner
2012-11-12 11:09 ` [PATCH 1/3] xfs: fix attr tree double split corruption Dave Chinner
2012-11-12 19:10 ` Mark Tinguely
2012-11-12 11:09 ` [PATCH 2/3] xfs: fix broken error handling in xfs_vm_writepage Dave Chinner
2012-11-13 14:27 ` Mark Tinguely
2012-11-12 11:09 ` [PATCH 3/3] xfs: drop buffer io reference when a bad bio is built Dave Chinner
2012-11-12 20:51 ` Mark Tinguely [this message]
2012-11-13 2:01 ` [PATCH 0/3] xfs: fixes for 3.7-rc6 Ben Myers
2012-11-13 3:05 ` Dave Chinner
2012-11-13 7:11 ` Christoph Hellwig
2012-11-13 19:46 ` Dave Chinner
2012-11-13 21:20 ` Ben Myers
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=50A1615F.10809@sgi.com \
--to=tinguely@sgi.com \
--cc=david@fromorbit.com \
--cc=xfs@oss.sgi.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.