From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 3/5] xfs: use xfs_ilock_map_shared in xfs_qm_dqiterate
Date: Fri, 6 Dec 2013 07:45:38 +1100 [thread overview]
Message-ID: <20131205204538.GC29897@dastard> (raw)
In-Reply-To: <20131205155951.506063990@bombadil.infradead.org>
On Thu, Dec 05, 2013 at 07:58:33AM -0800, Christoph Hellwig wrote:
> We might not have read in the extent list at this point, so make sure we
> take the ilock exclusively if we have to do so.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Index: xfs/fs/xfs/xfs_qm.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_qm.c 2013-11-18 14:39:01.967589998 +0100
> +++ xfs/fs/xfs/xfs_qm.c 2013-12-05 12:32:36.623617997 +0100
> @@ -1193,16 +1193,18 @@ xfs_qm_dqiterate(
> lblkno = 0;
> maxlblkcnt = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
> do {
> + uint lock_mode;
> +
> nmaps = XFS_DQITER_MAP_SIZE;
> /*
> * We aren't changing the inode itself. Just changing
> * some of its data. No new blocks are added here, and
> * the inode is never added to the transaction.
> */
> - xfs_ilock(qip, XFS_ILOCK_SHARED);
> + lock_mode = xfs_ilock_map_shared(qip);
> error = xfs_bmapi_read(qip, lblkno, maxlblkcnt - lblkno,
> map, &nmaps, 0);
> - xfs_iunlock(qip, XFS_ILOCK_SHARED);
> + xfs_iunlock_map_shared(qip, lock_mode);
> if (error)
> break;
There's no bug here - this comes from quotacheck, which is
guaranteed to have exclusive access to the filesystem at this point.
Hence there's no-one to race with reading the extent list. Still, it
doesn't hurt.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2013-12-05 20:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-05 15:58 [PATCH 0/5] extent list locking fixes Christoph Hellwig
2013-12-05 15:58 ` [PATCH 1/5] xfs: take the ilock around xfs_bmapi_read in xfs_zero_remaining_bytes Christoph Hellwig
2013-12-05 19:38 ` Ben Myers
2013-12-05 20:31 ` Dave Chinner
2013-12-05 20:37 ` Ben Myers
2013-12-05 20:40 ` Christoph Hellwig
2013-12-05 15:58 ` [PATCH 2/5] xfs: use xfs_ilock_map_shared in xfs_qm_dqtobp Christoph Hellwig
2013-12-05 19:46 ` Ben Myers
2013-12-05 20:41 ` Dave Chinner
2013-12-05 20:53 ` Christoph Hellwig
2013-12-05 21:03 ` Dave Chinner
2013-12-05 15:58 ` [PATCH 3/5] xfs: use xfs_ilock_map_shared in xfs_qm_dqiterate Christoph Hellwig
2013-12-05 19:48 ` Ben Myers
2013-12-05 20:45 ` Dave Chinner [this message]
2013-12-05 15:58 ` [PATCH 4/5] xfs: use xfs_ilock_map_shared in xfs_attr_get Christoph Hellwig
2013-12-05 19:57 ` Ben Myers
2013-12-05 20:59 ` Dave Chinner
2013-12-05 21:01 ` Christoph Hellwig
2013-12-05 21:05 ` Dave Chinner
2013-12-05 21:10 ` Christoph Hellwig
2013-12-05 21:17 ` Dave Chinner
2013-12-05 15:58 ` [PATCH 5/5] xfs: assert that we hold the ilock for extent map access Christoph Hellwig
2013-12-05 20:11 ` Ben Myers
2013-12-05 21:10 ` Dave Chinner
2013-12-05 21:22 ` Christoph Hellwig
2013-12-05 21:40 ` Dave Chinner
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