From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, Brian Foster <bfoster@redhat.com>,
linux-xfs@vger.kernel.org, hch@infradead.org
Subject: Re: [PATCH 4/4] xfs: force writes to delalloc regions to unwritten
Date: Fri, 22 May 2020 13:31:02 +1000 [thread overview]
Message-ID: <20200522033102.GD2040@dread.disaster.area> (raw)
In-Reply-To: <159011600308.76931.7853207930055232164.stgit@magnolia>
On Thu, May 21, 2020 at 07:53:23PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
>
> When writing to a delalloc region in the data fork, commit the new
> allocations (of the da reservation) as unwritten so that the mappings
> are only marked written once writeback completes successfully. This
> fixes the problem of stale data exposure if the system goes down during
> targeted writeback of a specific region of a file, as tested by
> generic/042.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Brian Foster <bfoster@redhat.com>
Observation: yesterday I forced a 4kB file create workload
to use unwritten extents by setting an extent size hint. That caused
about 4,500 xfs-conv kworker threads to be spawned by the workload
which had 16 userspace processes creating files...
I expect that any sort of "create lots of small files" worklaod is
going to cause xfs-conv kworker explosions, so be prepared for users
to start reporting kworker explosions with this in place...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-05-22 3:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 2:52 [PATCH v3 0/4] xfs: fix stale disk exposure after crash Darrick J. Wong
2020-05-22 2:53 ` [PATCH 1/4] xfs: don't fail unwritten extent conversion on writeback due to edquot Darrick J. Wong
2020-05-22 2:53 ` [PATCH 2/4] xfs: measure all contiguous previous extents for prealloc size Darrick J. Wong
2020-05-22 6:56 ` Christoph Hellwig
2020-05-23 0:25 ` Darrick J. Wong
2020-05-22 11:27 ` Brian Foster
2020-05-23 0:27 ` Darrick J. Wong
2020-05-23 7:09 ` Christoph Hellwig
2020-05-22 2:53 ` [PATCH 3/4] xfs: refactor xfs_iomap_prealloc_size Darrick J. Wong
2020-05-22 6:57 ` Christoph Hellwig
2020-05-22 2:53 ` [PATCH 4/4] xfs: force writes to delalloc regions to unwritten Darrick J. Wong
2020-05-22 3:31 ` Dave Chinner [this message]
2020-05-22 3:56 ` Darrick J. Wong
2020-05-23 16:49 [PATCH v4 0/4] xfs: fix stale disk exposure after crash Darrick J. Wong
2020-05-23 16:49 ` [PATCH 4/4] xfs: force writes to delalloc regions to unwritten Darrick J. Wong
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