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From: Christoph Hellwig <hch@infradead.org>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-xfs@vger.kernel.org, Jan Kara <jack@suse.cz>
Subject: Re: [PATCH 1/3] vfs: Add page_cache_seek_hole_data helper
Date: Mon, 26 Jun 2017 03:41:56 -0700	[thread overview]
Message-ID: <20170626104156.GA23149@infradead.org> (raw)
In-Reply-To: <1498177173-30798-1-git-send-email-agruenba@redhat.com>

On Fri, Jun 23, 2017 at 02:19:31AM +0200, Andreas Gruenbacher wrote:
> Both ext4 and xfs implement seeking for the next hole or piece of data
> in unwritten extents by scanning the page cache, and both versions share
> the same bug when iterating the buffers of a page: the start offset into
> the page isn't taken into account, so when a page fits more than two
> filesystem blocks, things will go wrong.  For example, on a filesystem
> with a block size of 1k, the following command will fail:
> 
>   xfs_io -f -c "falloc 0 4k" \
>             -c "pwrite 1k 1k" \
>             -c "pwrite 3k 1k" \
>             -c "seek -a -r 0" foo

Can you wire this up for xfstests, please?

  parent reply	other threads:[~2017-06-26 10:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-23  0:19 [PATCH 1/3] vfs: Add page_cache_seek_hole_data helper Andreas Gruenbacher
2017-06-23  0:19 ` [PATCH 2/3] ext4: Switch to page_cache_seek_hole_data Andreas Gruenbacher
2017-06-23  0:19 ` [PATCH 3/3] xfs: " Andreas Gruenbacher
2017-06-26 10:41 ` Christoph Hellwig [this message]
2017-06-26 10:51   ` [PATCH 1/3] vfs: Add page_cache_seek_hole_data helper Andreas Gruenbacher

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