From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 4/4] Revert "xfs: grab dquots without taking the ilock"
Date: Thu, 13 Jul 2017 18:36:28 +0200 [thread overview]
Message-ID: <20170713163628.GA4187@lst.de> (raw)
In-Reply-To: <20170713163127.GA4151@magnolia>
On Thu, Jul 13, 2017 at 09:31:27AM -0700, Darrick J. Wong wrote:
> On Thu, Jul 13, 2017 at 01:33:04PM +0200, Christoph Hellwig wrote:
> > This reverts commit 50e0bdbe9f48f98bb02eac7030d682f4716884ae.
> >
> > The new XFS_QMOPT_NOLOCK isn't used at all,
>
> It'll get used (eventually) by online fsck.
As-is that will lead to buggy code. xfs_qm_dqread does transaction
allocations and disk reads, and none of those should be allowed
under the ILOCK ever. That whole callchain is a mess and will need
some refactoring love to start with, e.g. including the dropping
of the ilock around the xfs_qm_dqread call in xfs_qm_dqget, and
a general mess of mixing up way to many things through the xfs_qm_dqget()
interface.
> > and conditional locking based on a flag is always the wrong thing to
> > do - we should be having helpers that can be called without the lock
> > instead.
>
> Fair enough. How about this instead:
Just as bad.
next prev parent reply other threads:[~2017-07-13 16:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-13 11:33 fixups for the changes in 4.13 Christoph Hellwig
2017-07-13 11:33 ` [PATCH 1/4] xfs: fixup xfs_attr_get_ilocked Christoph Hellwig
2017-07-13 19:23 ` Darrick J. Wong
2017-07-13 11:33 ` [PATCH 2/4] xfs: assert locking precondіtion in xfs_attr_list_int_ilocked Christoph Hellwig
2017-07-13 19:23 ` Darrick J. Wong
2017-07-13 11:33 ` [PATCH 3/4] xfs: assert locking precondition in xfs_readlink_bmap_ilocked Christoph Hellwig
2017-07-13 19:23 ` Darrick J. Wong
2017-07-13 11:33 ` [PATCH 4/4] Revert "xfs: grab dquots without taking the ilock" Christoph Hellwig
2017-07-13 16:31 ` Darrick J. Wong
2017-07-13 16:36 ` Christoph Hellwig [this message]
2017-07-13 19:22 ` Darrick J. Wong
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