linux-kernel - Re: [PATCH 0/4] Remove possible deadlocks in nfs_release

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Message-ID: <20140916201929.2e355cae@tlielax.poochiereds.net>
Date:	Tue, 16 Sep 2014 20:19:29 -0400
From:	Jeff Layton <jeff.layton@...marydata.com>
To:	NeilBrown <neilb@...e.de>
Cc:	Jeff Layton <jeff.layton@...marydata.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Trond Myklebust <trond.myklebust@...marydata.com>,
	Ingo Molnar <mingo@...hat.com>, linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/4] Remove possible deadlocks in nfs_release_page()

On Wed, 17 Sep 2014 09:41:13 +1000
NeilBrown <neilb@...e.de> wrote:

> On Tue, 16 Sep 2014 07:47:41 -0400 Jeff Layton <jeff.layton@...marydata.com>
> wrote:
> 
> 
> > Also, we call things like invalidate_complete_page2 from the cache
> > invalidation code. Will we end up with potential problems now that we
> > have a stronger possibility that a page might not be freeable when it
> > calls releasepage? (no idea on this -- I'm just spitballing)
> > 
> 
> Answering just this part here:
>  invalidate_complete_page2() is only called immediately after a call to
> do_launder_page().
> For nfs, that means nfs_launder_page() was called, which calls nfs_wb_page()
> which in turn calls
> 		ret = nfs_commit_inode(inode, FLUSH_SYNC);
> 
> so the inode is fully committed when invalidate_complete_page2 is called, so
> nfs_release_page will succeed.
> 
> So there shouldn't be a problem there.
> 

Yep, Trond pointed that out today when we were discussing it. Thanks
for confirming it here though...

-- 
Jeff Layton <jlayton@...marydata.com>

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