From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: xfs <linux-xfs@vger.kernel.org>
Subject: Re: [PATCH] xfs: avoid mount-time deadlock in CoW extent recovery
Date: Wed, 17 May 2017 10:39:31 +1000 [thread overview]
Message-ID: <20170517003931.GN17542@dastard> (raw)
In-Reply-To: <20170516192748.GQ4519@birch.djwong.org>
On Tue, May 16, 2017 at 12:27:48PM -0700, Darrick J. Wong wrote:
> If a malicious user corrupts the refcount btree to cause a cycle between
> different levels of the tree, the next mount attempt will deadlock in
> the CoW recovery routine while grabbing buffer locks. We can use the
> ability to re-grab a buffer that was previous locked to a transaction to
> avoid deadlocks, so do that here.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Missing comments in the code explaining the deadlock being avoided
by using xfs_trans_alloc_empty()....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2017-05-17 0:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-16 19:27 [PATCH] xfs: avoid mount-time deadlock in CoW extent recovery Darrick J. Wong
2017-05-17 0:39 ` Dave Chinner [this message]
2017-05-17 1:06 ` Darrick J. Wong
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=20170517003931.GN17542@dastard \
--to=david@fromorbit.com \
--cc=darrick.wong@oracle.com \
--cc=linux-xfs@vger.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;
as well as URLs for NNTP newsgroup(s).