From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 3/3] xfs: actually account for quota changes in xfs_swap_extents
Date: Wed, 6 May 2020 09:34:24 -0700 [thread overview]
Message-ID: <20200506163424.GT5703@magnolia> (raw)
In-Reply-To: <20200506145728.GC7864@infradead.org>
On Wed, May 06, 2020 at 07:57:28AM -0700, Christoph Hellwig wrote:
> On Mon, May 04, 2020 at 06:10:29PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> >
> > Currently, xfs_swap_extents neither checks for sufficient quota
> > reservation nor does it actually update quota counts when swapping the
> > extent forks. While the primary known user of extent swapping (xfs_fsr)
> > is careful to ensure that the user/group/project ids of both files
> > match, this is not required by the kernel. Consequently, unprivileged
> > userspace can cause the quota counts to be incorrect.
>
> Wouldn't be the right fix to enforce an id match? I think that is a
> very sensible limitation.
One could do that, but at a cost of breaking any userspace program that
was using XFS_IOC_SWAPEXT and was not aware that the ids had to match
(possibly due to the lack of documentation...)
It was trivial enough to port this from the atomic file update series,
so I decided to post the least functionality-reducing version and see
what happens.
Thoughts?
--D
next prev parent reply other threads:[~2020-05-06 16:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 1:10 [PATCH 0/3] xfs: random SWAPEXT fixes Darrick J. Wong
2020-05-05 1:10 ` [PATCH 1/3] xfs: clean up the error handling in xfs_swap_extents Darrick J. Wong
2020-05-06 14:46 ` Christoph Hellwig
2020-05-05 1:10 ` [PATCH 2/3] xfs: clean up the metadata validation in xfs_swap_extent_rmap Darrick J. Wong
2020-05-06 14:56 ` Christoph Hellwig
2020-05-06 16:45 ` Darrick J. Wong
2020-05-05 1:10 ` [PATCH 3/3] xfs: actually account for quota changes in xfs_swap_extents Darrick J. Wong
2020-05-06 14:57 ` Christoph Hellwig
2020-05-06 16:34 ` Darrick J. Wong [this message]
2020-05-07 6:02 ` Christoph Hellwig
2020-05-12 23:42 ` Darrick J. Wong
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