From: Dave Chinner <david@fromorbit.com>
To: Allison Henderson <achender@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
Andreas Dilger <adilger@dilger.ca>
Subject: Re: lock i_mutex for fallocate?
Date: Thu, 1 Sep 2011 17:08:48 +1000 [thread overview]
Message-ID: <20110901070848.GQ32358@dastard> (raw)
In-Reply-To: <4E5ED2D5.8040302@linux.vnet.ibm.com>
On Wed, Aug 31, 2011 at 05:33:25PM -0700, Allison Henderson wrote:
> Hi All,
>
> In ext4 punch hole, we realized that the punch hole operation needs
> to be done under i_mutex just like truncate. i_mutex for truncate
> is held in the vfs layer, so we dont need to lock it at the file
> system layer, but vfs does not lock i_mutex for fallocate. We can
> lock i_mutex for fallocate at the fs layer, but question was raised
> then: should i_mutex for fallocate be held in the vfs layer instead?
No.
> I do not know if other file systems need i_mutex to be locked for
> fallocate,
For one, XFS does not require i_mutex to be held for any extent
manipulation of any kind (allocation, truncation, hole punch,
unwritten extent conversion, etc).
Hence the current structure of having the filesystem take i_mutex if
it needs it to protect allocations against races is appropriate.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2011-09-01 7:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-01 0:33 lock i_mutex for fallocate? Allison Henderson
2011-09-01 1:10 ` Yongqiang Yang
2011-09-01 1:10 ` Yongqiang Yang
2011-09-01 1:12 ` Allison Henderson
2011-09-01 17:59 ` Josef Bacik
2011-09-01 7:08 ` Dave Chinner [this message]
2011-09-01 7:31 ` Christoph Hellwig
2011-09-01 17:47 ` Allison Henderson
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=20110901070848.GQ32358@dastard \
--to=david@fromorbit.com \
--cc=achender@linux.vnet.ibm.com \
--cc=adilger@dilger.ca \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@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 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.