From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Josef Bacik <josef@toxicpanda.com>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>,
David Sterba <dsterba@suse.com>,
"linux-btrfs @ vger . kernel . org" <linux-btrfs@vger.kernel.org>,
Filipe Manana <fdmanana@gmail.com>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC PATCH] btrfs: don't call btrfs_sync_file from iomap context
Date: Mon, 7 Sep 2020 10:04:32 +1000 [thread overview]
Message-ID: <20200907000432.GM12096@dread.disaster.area> (raw)
In-Reply-To: <20200903163236.GA26043@lst.de>
On Thu, Sep 03, 2020 at 06:32:36PM +0200, Christoph Hellwig wrote:
> We could trivially do something like this to allow the file system
> to call iomap_dio_complete without i_rwsem:
That just exposes another deadlock vector:
P0 P1
inode_lock() fallocate(FALLOC_FL_ZERO_RANGE)
__iomap_dio_rw() inode_lock()
<block>
<submits IO>
<completes IO>
inode_unlock()
<gets inode_lock()>
inode_dio_wait()
iomap_dio_complete()
generic_write_sync()
btrfs_file_fsync()
inode_lock()
<deadlock>
Basically, the only safe thing to do is implement ->fsync without
holding the DIO IO submission lock....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-09-07 0:04 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200901130644.12655-1-johannes.thumshirn@wdc.com>
2020-09-01 15:11 ` [RFC PATCH] btrfs: don't call btrfs_sync_file from iomap context Josef Bacik
2020-09-01 17:45 ` Darrick J. Wong
2020-09-01 17:55 ` Josef Bacik
2020-09-01 21:46 ` Dave Chinner
2020-09-01 22:19 ` Josef Bacik
2020-09-01 23:58 ` Dave Chinner
2020-09-02 0:22 ` Josef Bacik
2020-09-02 7:12 ` Johannes Thumshirn
2020-09-02 11:10 ` Josef Bacik
2020-09-02 16:29 ` Darrick J. Wong
2020-09-02 16:47 ` Josef Bacik
2020-09-02 11:44 ` Matthew Wilcox
2020-09-02 12:20 ` Dave Chinner
2020-09-02 12:42 ` Josef Bacik
2020-09-03 2:28 ` Dave Chinner
2020-09-03 9:49 ` Filipe Manana
2020-09-03 16:32 ` Christoph Hellwig
2020-09-03 16:46 ` Josef Bacik
2020-09-07 0:04 ` Dave Chinner [this message]
2020-09-15 21:48 ` Goldwyn Rodrigues
2020-09-17 3:09 ` Dave Chinner
2020-09-17 5:52 ` Christoph Hellwig
2020-09-17 6:29 ` Dave Chinner
2020-09-17 6:42 ` Christoph Hellwig
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=20200907000432.GM12096@dread.disaster.area \
--to=david@fromorbit.com \
--cc=dsterba@suse.com \
--cc=fdmanana@gmail.com \
--cc=hch@lst.de \
--cc=johannes.thumshirn@wdc.com \
--cc=josef@toxicpanda.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-fsdevel@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