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From: Stephen Rothwell <sfr@canb.auug.org.au>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
	Nathan Zimmer <nzimmer@sgi.com>
Subject: Re: linux-next: manual merge of the akpm tree with the vfs tree
Date: Fri, 5 Apr 2013 10:18:53 +1100	[thread overview]
Message-ID: <20130405101853.769d3b915cacd8a4863b7c19@canb.auug.org.au> (raw)
In-Reply-To: <20130404081011.GO21522@ZenIV.linux.org.uk>

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Hi Al,

On Thu, 4 Apr 2013 09:10:11 +0100 Al Viro <viro@ZenIV.linux.org.uk> wrote:
>
> On Thu, Apr 04, 2013 at 12:02:53AM -0700, Andrew Morton wrote:
> 
> > > Well perhaps the vfs tree should start paying some attention to the
> > > rest of the world, particularly after -rc5.
> > 
> > I can't even find this "lift sb_start_write() out of ->write()".  Not on fsdevel,
> > not on lkml.  What the heck is it and why was it so important?
> 
> Deadlocks around splice; see the threads re overlayfs/unionmount/aufs and
> deadlocks in their copyup implementations.  See also XFS freeze-related
> deadlocks, etc.
> 
> The thing is, sb_start_write() is pretty high in locking hierarchy (outside
> ->i_mutex, etc.), but ->splice_write() and friends had it buried pretty
> deep.  With distinctly unpleasant results, including ->..._write() instances
> using generic ones (which took the lock) *and* doing some IO outside of those
> (ext4, for example; ocfs2 also looked fishy in that respect, IIRC).
> 
> The obvious solution is to lift taking that lock out of the methods, which
> had been done.  It had been discussed on fsdevel and sat in #experimental for
> several weeks; time for it to go into #for-next.

It would have been useful to put something like that in the commit message ...

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au

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  reply	other threads:[~2013-04-04 23:19 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-04  6:26 Stephen Rothwell
2013-04-04  6:56 ` Andrew Morton
2013-04-04  7:02   ` Andrew Morton
2013-04-04  8:10     ` Al Viro
2013-04-04 23:18       ` Stephen Rothwell [this message]
2013-04-04  8:02   ` Al Viro
2013-04-04 15:43     ` Nathan Zimmer
  -- strict thread matches above, loose matches on Subject: below --
2020-05-15 11:33 Stephen Rothwell
2019-04-11  6:21 Stephen Rothwell
2018-05-17  6:36 Stephen Rothwell
2018-01-02  6:46 Stephen Rothwell
2016-12-12  5:52 Stephen Rothwell
2016-12-12  8:14 ` Ian Kent
2014-08-08  6:20 Stephen Rothwell
2013-09-10  4:41 Stephen Rothwell
2013-09-05  8:56 Stephen Rothwell
2013-04-30  5:54 Stephen Rothwell
2013-04-29  8:34 Stephen Rothwell
2013-04-29  8:25 Stephen Rothwell
2013-04-04  6:17 Stephen Rothwell
2013-04-04  6:12 Stephen Rothwell
2013-04-04 12:33 ` Jan Kara
2013-04-04  6:04 Stephen Rothwell
2013-02-25  3:40 Stephen Rothwell
2012-09-24 13:40 Stephen Rothwell
2012-09-24 13:12 Stephen Rothwell
2012-09-24 13:06 Stephen Rothwell
2012-07-22  5:44 Stephen Rothwell
2011-07-18  8:55 Stephen Rothwell

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