From: Jan Kara <jack@suse.cz>
To: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: Ben Myers <bpm@sgi.com>, Jan Kara <jack@suse.cz>,
swhiteho@redhat.com, xfs@oss.sgi.com
Subject: Re: [PATCH v10 10/11] quota: Add proper versioning support to fs_quota_stat
Date: Wed, 10 Jul 2013 23:54:51 +0200 [thread overview]
Message-ID: <20130710215451.GB1641@quack.suse.cz> (raw)
In-Reply-To: <1373489390.6020.30.camel@chandra-dt.ibm.com>
On Wed 10-07-13 15:49:50, Chandra Seetharaman wrote:
> On Wed, 2013-07-10 at 18:26 +0200, Jan Kara wrote:
> > On Wed 10-07-13 10:55:38, Ben Myers wrote:
> > > Hey Chandra,
>
> <snip>
>
> > > > diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> > > > index c7314f1..ae6526e 100644
> > > > --- a/fs/quota/quota.c
> > > > +++ b/fs/quota/quota.c
> > > > @@ -207,12 +207,57 @@ static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
> > > > static int quota_getxstate(struct super_block *sb, void __user *addr)
> > > > {
> > > > struct fs_quota_stat fqs;
> > > > - int ret;
> > > > + struct fs_quota_stat_v1 fqs_v1;
> > > > + int ret, size;
> > > > + void *fqsp;
> > > >
> > > > if (!sb->s_qcop->get_xstate)
> > > > return -ENOSYS;
> > > > +
> > > > + memset(&fqs, 0, sizeof(struct fs_quota_stat));
> > > > + if (copy_from_user(&fqs, addr, 1)) /* just get the version */
> > > > + return -EFAULT;
> > > > +
> > > > + switch (fqs.qs_version) {
> > > > + case FS_QSTAT_VERSION_2:
> > > > + size = FS_QSTAT_V2_SIZE;
> > > > + break;
> > > > + default:
> > > > + fqs.qs_version = FS_QSTAT_VERSION;
> > > > + /* fallthrough */
> > > > + case FS_QSTAT_VERSION:
> > > > + size = FS_QSTAT_V1_SIZE;
> > > > + break;
> > > > + }
> > Guys, you cannot really do this. If anyone is using getxstate() with
> > uninitialized buffer (which is fine so far), you cannot suddently start to
> > rely on the contents of qs_version field. That's ABI (and even API)
> > breakage.
>
> Agree, it is a API breakage.
>
> Will fix it by adding a new quotactl value as you suggest.
> Does
>
> #define Q_XGETQSTAT2 XQM_CMD(8)
>
> sound good ?
Ben's Q_XGETQSTATV name looked a bit better to me but I don't really
care. Whatever works for you...
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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next prev parent reply other threads:[~2013-07-10 21:54 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 22:25 [PATCH v10 00/11] Allow pquota and gquota to be used together Chandra Seetharaman
2013-06-27 22:25 ` [PATCH v10 01/11] xfs: Define a new function xfs_is_quota_inode() Chandra Seetharaman
2013-06-27 22:43 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 02/11] xfs: Replace macro XFS_DQUOT_TREE with a function Chandra Seetharaman
2013-06-27 23:19 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 03/11] xfs: Replace macro XFS_DQ_TO_QIP " Chandra Seetharaman
2013-06-27 23:23 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 04/11] xfs: Code cleanup and removal of some typedef usage Chandra Seetharaman
2013-06-27 23:50 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 05/11] xfs: Do some whitespace cleanup in the data structure xfs_quotainfo Chandra Seetharaman
2013-06-28 16:30 ` Ben Myers
2013-06-28 18:14 ` Chandra Seetharaman
2013-06-28 18:31 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 06/11] xfs: Change xfs_dquot_acct to be a 2-dimensional array Chandra Seetharaman
2013-06-28 19:06 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 07/11] xfs: Remove incore use of XFS_OQUOTA_ENFD and XFS_OQUOTA_CHKD Chandra Seetharaman
2013-06-28 22:36 ` Ben Myers
2013-06-27 22:25 ` [PATCH v10 08/11] xfs: Add pquota fields where gquota is used Chandra Seetharaman
2013-07-10 21:39 ` Ben Myers
2013-07-10 21:46 ` Chandra Seetharaman
2013-07-11 1:23 ` Dave Chinner
2013-07-11 4:05 ` Chandra Seetharaman
2013-06-27 22:25 ` [PATCH v10 09/11] xfs: Start using pquotaino from the superblock Chandra Seetharaman
2013-07-01 2:06 ` Dave Chinner
2013-07-01 17:59 ` Chandra Seetharaman
2013-07-03 17:12 ` Chandra Seetharaman
2013-07-04 1:35 ` Dave Chinner
2013-06-27 22:25 ` [PATCH v10 10/11] quota: Add proper versioning support to fs_quota_stat Chandra Seetharaman
2013-07-10 15:55 ` Ben Myers
2013-07-10 16:26 ` Jan Kara
2013-07-10 18:47 ` Ben Myers
2013-07-10 21:52 ` Jan Kara
2013-07-10 20:49 ` Chandra Seetharaman
2013-07-10 21:54 ` Jan Kara [this message]
2013-07-11 1:45 ` Dave Chinner
2013-07-11 4:16 ` Chandra Seetharaman
2013-07-11 7:18 ` Dave Chinner
2013-07-11 7:51 ` Steven Whitehouse
2013-06-27 22:25 ` [PATCH v10 11/11] xfs: Use new qs_pquota field in fs_quota_stat for Q_XGETQSTAT Chandra Seetharaman
2013-06-28 22:53 ` [PATCH v10 00/11] Allow pquota and gquota to be used together Ben Myers
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