Date: Mon, 29 Jan 2007 17:51:59 -0800
From: Mark Fasheh <mark.fasheh@oracle.com>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       Linux Memory Management <linux-mm@kvack.org>,
       David Howells <dhowells@redhat.com>, Andrew Morton <akpm@osdl.org>,
       Anton Altaparmakov <aia21@cam.ac.uk>
Subject: Re: page_mkwrite caller is racy?
Message-ID: <20070130015159.GA14799@ca-server1.us.oracle.com>
Reply-To: Mark Fasheh <mark.fasheh@oracle.com>
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On Tue, Jan 30, 2007 at 12:14:24PM +1100, Nick Piggin wrote:
> This is another discussion, but do we want the page locked here? Or
> are the filesystems happy to exclude truncate themselves?

No page lock please. Generally, Ocfs2 wants to order cluster locks outside
of page locks. Also, the sparse b-tree support I'm working on right now will
need to be able to allocate in ->page_mkwrite() which would become very
nasty if we came in with the page lock - aside from the additional cluster
locks taken, ocfs2 will want to zero some adjacent pages (because we support
atomic allocation up to 1 meg).

Thanks,
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com
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