From: Jan Kara <jack@suse.cz>
To: Dave Jiang <dave.jiang@intel.com>
Cc: lczerner@redhat.com, jack@suse.cz, linux-nvdimm@lists.01.org,
darrick.wong@oracle.com, david@fromorbit.com,
linux-xfs@vger.kernel.org, zwisler@kernel.org,
linux-fsdevel@vger.kernel.org, tytso@mit.edu,
linux-ext4@vger.kernel.org, hch@lst.de
Subject: Re: [PATCH 2/2] [PATCH] xfs: Close race between direct IO and xfs_break_layouts()
Date: Wed, 8 Aug 2018 10:53:39 +0200 [thread overview]
Message-ID: <20180808085339.GD15413@quack2.suse.cz> (raw)
In-Reply-To: <153367990333.37314.16218849614019392916.stgit@djiang5-desk3.ch.intel.com>
On Tue 07-08-18 15:11:43, Dave Jiang wrote:
> This patch is the duplicate of ross's fix for ext4 for xfs.
>
> If the refcount of a page is lowered between the time that it is returned
> by dax_busy_page() and when the refcount is again checked in
> xfs_break_layouts() => ___wait_var_event(), the waiting function
> xfs_wait_dax_page() will never be called. This means that
> xfs_break_layouts() will still have 'retry' set to false, so we'll stop
> looping and never check the refcount of other pages in this inode.
>
> Instead, always continue looping as long as dax_layout_busy_page() gives us
> a page which it found with an elevated refcount.
>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Just one minor nit below:
> @@ -746,9 +744,10 @@ xfs_break_dax_layouts(
> if (!page)
> return 0;
>
> + *did_unlock = true;
I think it would be more understandable to name the argument of
xfs_break_dax_layouts() as 'retry' instead of 'did_unlock' as it's not
about unlocking anymore.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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next prev parent reply other threads:[~2018-08-08 8:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 22:11 [PATCH 1/2] ext4: Close race between direct IO and ext4_break_layouts() Dave Jiang
2018-08-07 22:11 ` [PATCH 2/2] [PATCH] xfs: Close race between direct IO and xfs_break_layouts() Dave Jiang
2018-08-08 8:53 ` Jan Kara [this message]
2018-08-08 15:47 ` Dave Jiang
2018-08-08 8:49 ` [PATCH 1/2] ext4: Close race between direct IO and ext4_break_layouts() Jan Kara
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