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From: Christoph Hellwig <hch@infradead.org>
To: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com, aelder@sgi.com
Subject: Re: [PATCH] xfs: only SetPageUptodate if all buffers are uptodate
Date: Wed, 20 Apr 2011 06:35:21 -0400	[thread overview]
Message-ID: <20110420103521.GA20510@infradead.org> (raw)
In-Reply-To: <20110419114028.7844.10303.stgit@nfs3>

On Tue, Apr 19, 2011 at 06:40:28AM -0500, Ben Myers wrote:
> xfs_vm_writepage and xfs_page_convert set a page uptodate if it is determined
> that all of the buffer_heads attached to that page are uptodate.
> 
> Currently we use the flag variable 'uptodate'.  The flag is initially set = 1
> and it is cleared if a !buffer_uptodate buffer is encountered.  In addition we
> check that bh == head in order to ensure that all of the buffer_heads have been
> checked.  However, it is possible to break out of the buffer_head loop early
> having processed only the first buffer.  This leaves uptodate == 1 and bh ==
> head, so the uptodate bit can be set on a page even if not all of the buffers
> have been checked.  This can lead to data corruption on platforms with > 1
> buffer per page.

Dou have a testcase to reproduce this issue?

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  reply	other threads:[~2011-04-20 10:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-19 11:40 [PATCH] xfs: only SetPageUptodate if all buffers are uptodate Ben Myers
2011-04-20 10:35 ` Christoph Hellwig [this message]
2011-04-20 14:57   ` bpm
2011-04-20 15:36     ` Christoph Hellwig
2011-06-23  5:08       ` Dave Chinner
2011-06-23  6:09         ` Dave Chinner
2011-06-23 10:35           ` Dave Chinner

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