From: Dave Chinner <david@fromorbit.com>
To: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 14/15] xfs: dquot log reservations are too small
Date: Sat, 29 Jun 2013 12:42:05 +1000 [thread overview]
Message-ID: <20130629024205.GF9047@dastard> (raw)
In-Reply-To: <1372439902.8341.155.camel@chandra-dt.ibm.com>
On Fri, Jun 28, 2013 at 12:18:22PM -0500, Chandra Seetharaman wrote:
>
> some nits below on commit log and comments.
>
> otherwise consider
>
> Reviewed-by: Chandra Seethraman <sekharan@us.ibm.com>
>
> On Thu, 2013-06-27 at 16:04 +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > During review of the separate project quota inode patches, it bcame
> became(typo)
>
> > obvious that the dquot log reservation calculation underestimated
> > the number dquots that can be modified in a transaction. This has
> > it's roots way back in the Irix quota implementation.
> >
> > That is, when quotas were first implemented in XFS, it only
> > supported user and project quotas as Irix did not have group quotas.
> > Hence the worst case operation involving dquot modification was
> > calculated to involve 2 user dquots and 1 project dquot or 1 user
> > dequot and 2 project dquots. i.e. 3 dquots. This was determined back
> > in 1996, and has remained unchanged ever since.
>
> How about the missing reservation for the log format header ? It is a
> day one problem, right ?
Yup.
> > However, back in 2001, the Linux XFS port dropped all support for
> > project quota and implmented group quotas over the top. This was
>
> implemented(typo)
>
> > effectively done with a search-and-replace of project with group,
> > and as such the log reservation was not changed. However, with the
> > advent of group quotas, chmod and rename now could modify more than
> > 3 dquots in a single transaction - both could modify 4 dquots. Hence
> > this log reservation has been wrong for a long time.
> >
> > In 2005, project quotas were reintroduced into Linux, but they were
>
> introduced ? (it was mentioned above that 2001 Linux port removed
> project quota, so it never existed in Linux ?!)
I'm talking from a code perspective, not whether they worked or not
from a user persepctive.....
> > implemented to be mutually exclusive to group quotas, and so this
> > didn't add any new changes to the dquot log reservation. hence when
> > project quotas were in use, everything was still fine, just like
> > in the Irix days.
>
> you can say that... but, when the group quota is used the problem
> mentioned above exists.
Yes, it does. All this points out was that group quotas were broken,
not project quotas....
I'll fix up the various typos and clarify the comments as you've
suggested.
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:[~2013-06-29 2:42 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 6:04 [PATCH 00/15] xfs: patchset for 3.11 Dave Chinner
2013-06-27 6:04 ` [PATCH 01/15] xfs: update mount options documentation Dave Chinner
2013-06-27 14:48 ` Ben Myers
2013-06-27 19:08 ` Ben Myers
2013-06-28 2:09 ` Dave Chinner
2013-06-28 2:32 ` Dave Chinner
2013-06-28 15:39 ` Geoffrey Wehrman
2013-06-28 16:49 ` Eric Sandeen
2013-06-28 19:58 ` Geoffrey Wehrman
2013-06-28 17:27 ` Ric Wheeler
2013-06-28 19:39 ` Ben Myers
2013-06-29 2:38 ` Dave Chinner
2013-06-28 2:18 ` Eric Sandeen
2013-06-28 20:46 ` Ben Myers
2013-06-27 6:04 ` [PATCH 02/15] xfs: add pluging for bulkstat readahead Dave Chinner
2013-06-27 6:04 ` [PATCH 03/15] xfs: plug directory buffer readahead Dave Chinner
2013-06-27 6:04 ` [PATCH 04/15] xfs: don't use speculative prealloc for small files Dave Chinner
2013-06-27 6:04 ` [PATCH 05/15] xfs: don't do IO when creating an new inode Dave Chinner
2013-06-27 6:04 ` [PATCH 06/15] xfs: xfs_ifree doesn't need to modify the inode buffer Dave Chinner
2013-06-27 6:04 ` [PATCH 07/15] xfs: Introduce ordered log vector support Dave Chinner
2013-06-27 6:04 ` [PATCH 08/15] xfs: Introduce an ordered buffer item Dave Chinner
2013-06-27 6:04 ` [PATCH 09/15] xfs: Inode create log items Dave Chinner
2013-06-27 6:04 ` [PATCH 10/15] xfs: Inode create transaction reservations Dave Chinner
2013-06-27 6:04 ` [PATCH 11/15] xfs: Inode create item recovery Dave Chinner
2013-06-27 6:04 ` [PATCH 12/15] xfs: Use inode create transaction Dave Chinner
2013-06-27 6:04 ` [PATCH 13/15] xfs: remove local fork format handling from xfs_bmapi_write() Dave Chinner
2013-06-27 6:04 ` [PATCH 14/15] xfs: dquot log reservations are too small Dave Chinner
2013-06-27 14:38 ` Mark Tinguely
2013-06-28 17:18 ` Chandra Seetharaman
2013-06-29 2:42 ` Dave Chinner [this message]
2013-07-09 19:31 ` Ben Myers
2013-07-09 20:39 ` Dave Chinner
2013-07-09 20:42 ` Ben Myers
2013-06-27 6:04 ` [PATCH 15/15] xfs: implement inode change count Dave Chinner
2013-06-27 15:06 ` Mark Tinguely
2013-06-28 16:07 ` Chandra Seetharaman
2013-06-28 18:00 ` Ben Myers
2013-06-27 19:48 ` [PATCH 00/15] xfs: patchset for 3.11 Ben Myers
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=20130629024205.GF9047@dastard \
--to=david@fromorbit.com \
--cc=sekharan@us.ibm.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