From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: Non-blocking inode locking in IO completion
Date: Wed, 17 Feb 2010 14:29:38 -0500 [thread overview]
Message-ID: <20100217192938.GA14015@infradead.org> (raw)
In-Reply-To: <1266384989-28928-1-git-send-email-david@fromorbit.com>
On Wed, Feb 17, 2010 at 04:36:29PM +1100, Dave Chinner wrote:
> The introduction of barriers to DM loop devices (e.g. dm-crypt) has
> created a new IO order completion dependency that XFS does not
> handle. That is, the completion of log IOs (which have barriers) in
> the loop filesystem are now dependent on completion of data IO in
> the backing filesystem.
I don't think dm belongs into the picture here at all. The problem
is simply with the loop device, which sits below dm-crypt in the
bugzilla reports. The loop device in SuSE (and for a short time in
mainline until we saw unexplainable XFS lockups) implements barriers
using fsync. Now that fsync turns a log I/O that issues a barrier
in the XFS filesystem inside the loop device into a data I/O the
backing filesystem. With this the rest of your description applies
again.
The patch looks good to me - while I hate introducing random delay()
calls I don't really see a way around this.
Reviewed-by: Christoph Hellwig <hch@lst.de>
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2010-02-17 19:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-17 5:36 [PATCH] xfs: Non-blocking inode locking in IO completion Dave Chinner
2010-02-17 19:29 ` Christoph Hellwig [this message]
2010-02-17 21:13 ` Dave Chinner
2010-02-18 12:35 ` Christoph Hellwig
2010-02-25 23:06 ` [PATCH V2] " Dave Chinner
2010-02-26 17:58 ` Alex Elder
2010-02-25 20:06 ` [PATCH] " Alex Elder
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=20100217192938.GA14015@infradead.org \
--to=hch@infradead.org \
--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.