From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@lst.de>
Subject: Re: writeback hang in current mainline
Date: Wed, 26 May 2010 15:42:08 +0200
Message-ID: <20100526134208.GA2557@lst.de>
References: <20100526111326.GA28541@lst.de> <20100526112125.GJ23411@kernel.dk> <20100526114018.GA30107@lst.de> <20100526114950.GK23411@kernel.dk> <20100526120855.GA30912@lst.de> <20100526122126.GL23411@kernel.dk> <20100526124549.GA32550@lst.de> <20100526125614.GM23411@kernel.dk>
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Cc: Christoph Hellwig <hch@lst.de>, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
To: Jens Axboe <jens.axboe@oracle.com>
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On Wed, May 26, 2010 at 02:56:15PM +0200, Jens Axboe wrote:
> On Wed, May 26 2010, Christoph Hellwig wrote:
> > On Wed, May 26, 2010 at 02:21:26PM +0200, Jens Axboe wrote:
> > > Ugh ok I see it, I had the caller_frees reverted. Try this :-)
> > 
> > This seems to fix it.  Running some more tests now.
> 
> Goodie, then the analysis at least is correct. A potentially cleaner fix
> would be to just allocate the WB_SYNC_NONE && sb_pinned work struct on
> the stack, since then we can get rid of that nastiness in
> wb_work_complete() as well (and not pass 'sb_pinned' around so much).
> 
> If you have time, care to test this one as well?

Both this and the previous one hang hard in xfstests 007, with no chance
of getting a backtrace.

For now I would recommend to revert
21c12849fef73efc9a898b6702fe421fd774f515 and
29c795f02e68ecd7bb1374844d3e55e882ac158f,
which makes xfstests run fine for me.