From: Dave Chinner <david@fromorbit.com>
To: Eric Sandeen <sandeen@redhat.com>
Cc: xfs-oss <xfs@oss.sgi.com>
Subject: Re: [PATCH, RFC] xfs: add heuristic to flush on rename
Date: Mon, 28 Apr 2014 07:20:26 +1000 [thread overview]
Message-ID: <20140427212026.GX18672@dastard> (raw)
In-Reply-To: <535ABA9D.2060305@redhat.com>
On Fri, Apr 25, 2014 at 02:42:21PM -0500, Eric Sandeen wrote:
> Add a heuristic to flush data to a file which looks like it's
> going through a tmpfile/rename dance, but not fsynced.
>
> I had a report of a system with many 0-length files after
> package updates; as it turns out, the user had basically
> done 'yum update' and punched the power button when it was
> done.
So yum didn't run sync() on completion of the update? That seems
rather dangerous to me - IMO system updates need to be guaranteed to
be stable by the update mechanisms, not to leave the system state to
chance if power fails or the system crashes immediately after an
update...
> Granted, the admin should not do this. Granted, the package
> manager should ensure persistence of files it updated.
Yes, yes it should. Problem solved without needing to touch XFS.
> Ext4, however, added a heuristic like this for just this case;
> someone who writes file.tmp, then renames over file, but
> never issues an fsync.
You mean like rsync does all the time for every file it copies?
> Now, this does smack of O_PONIES, but I would hope that it's
> fairly benign. If someone already synced the tmpfile, it's
> a no-op.
I'd suggest it will greatly impact rsync speed and have impact on
the resultant filesystem layout as it guarantees interleaving of
metadata and data on disk....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2014-04-27 21:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-25 19:42 [PATCH, RFC] xfs: add heuristic to flush on rename Eric Sandeen
2014-04-25 19:55 ` Christoph Hellwig
2014-04-25 19:59 ` Eric Sandeen
2014-04-25 20:00 ` Eric Sandeen
2014-04-27 21:20 ` Dave Chinner [this message]
2014-04-27 21:56 ` Eric Sandeen
2014-04-27 23:15 ` Dave Chinner
2014-04-28 0:20 ` Eric Sandeen
2014-04-28 0:48 ` Dave Chinner
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=20140427212026.GX18672@dastard \
--to=david@fromorbit.com \
--cc=sandeen@redhat.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 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).