From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH] xfsprogs: duplicate extent btrees in xfs_repair need locking
Date: Fri, 12 Mar 2010 05:13:04 -0500 [thread overview]
Message-ID: <20100312101304.GB15922@infradead.org> (raw)
In-Reply-To: <1268298930-20809-1-git-send-email-david@fromorbit.com>
On Thu, Mar 11, 2010 at 08:15:30PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> The per-ag duplicate extent btrees can be search concurrently from multiple
> threads. This occurs when inode extent lists are being processed and inodes
> with extents in the same AG are checked concurrently. The btrees have an
> internal traversal cursor, so doing concurrent searches can result in the
> cursor being corrupted for both searches.
>
> Add an external lock for each duplicate extent tree and use it for searches,
> inserts and deletes to ensure that we don't trash the state of any operation.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Note that all actual content modifications to the tree are done from
single threaded code, so strictly speaking we'd only need to lock in
search_dup_extent. Anyway, the locking shouldn't add enough overhead
to worry about this, so:
Reviewed-by: Christoph Hellwig <hch@lst.de>
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prev parent reply other threads:[~2010-03-12 10:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-11 9:15 [PATCH] xfsprogs: duplicate extent btrees in xfs_repair need locking Dave Chinner
2010-03-12 10:13 ` Christoph Hellwig [this message]
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