From: Josef Bacik <josef@toxicpanda.com>
To: josef@toxicpanda.com
Cc: linux-btrfs@vger.kernel.org, kernel-team@fb.com,
Josef Bacik <jbacik@fb.com>
Subject: Re: [PATCH 2/3] btrfs: fix readdir deadlock with pagefault
Date: Fri, 21 Jul 2017 15:10:29 -0400 [thread overview]
Message-ID: <20170721191028.GA17477@destiny> (raw)
In-Reply-To: <1500658149-20410-2-git-send-email-jbacik@fb.com>
On Fri, Jul 21, 2017 at 01:29:08PM -0400, josef@toxicpanda.com wrote:
> From: Josef Bacik <jbacik@fb.com>
>
> Readdir does dir_emit while under the btree lock. dir_emit can trigger
> the page fault which means we can deadlock. Fix this by allocating a
> buffer on opening a directory and copying the readdir into this buffer
> and doing dir_emit from outside of the tree lock.
>
> Signed-off-by: Josef Bacik <jbacik@fb.com>
This is broken, don't anybody actually run this, I'm more interested in comments
on the overall solution. I'll get it working and post a V2 after a few days if
nobody has objections to the approach as a whole. Thanks,
Josef
next prev parent reply other threads:[~2017-07-21 19:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-21 17:29 [PATCH 1/3] btrfs: don't allow trans ioctl on a directory josef
2017-07-21 17:29 ` [PATCH 2/3] btrfs: fix readdir deadlock with pagefault josef
2017-07-21 19:10 ` Josef Bacik [this message]
2017-07-24 8:26 ` Nikolay Borisov
2017-07-24 13:59 ` Josef Bacik
2017-07-24 12:50 ` David Sterba
2017-07-24 13:14 ` David Sterba
2017-07-24 14:01 ` Josef Bacik
2017-07-21 17:29 ` [PATCH 3/3] btrfs: increase ctx->pos for delayed dir index josef
2017-07-24 12:42 ` [PATCH 1/3] btrfs: don't allow trans ioctl on a directory David Sterba
2017-07-24 12:58 ` David Sterba
2017-07-24 14:02 ` Josef Bacik
2017-07-24 16:02 ` David Sterba
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