From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 870416B0069 for ; Wed, 2 Nov 2011 03:38:26 -0400 (EDT) Date: Wed, 2 Nov 2011 03:38:12 -0400 From: Christoph Hellwig Subject: Re: [PATCH] mm: Improve cmtime update on shared writable mmaps Message-ID: <20111102073812.GB17580@infradead.org> References: <6e365cb75f3318ab45d7145aededcc55b8ededa3.1319844715.git.luto@amacapital.net> <20111101225342.GG18701@quack.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: Jan Kara , Andreas Dilger , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org On Tue, Nov 01, 2011 at 04:02:24PM -0700, Andy Lutomirski wrote: > Hmm. Isn't it permitted to at least read from an fs while holding the > page lock? I thought that the page lock was held for the entire > duration of a read and at the beginning of writeback. > > I can push this down to the ->writepage implementations or to the > clear_page_dirty_for_io callers, but that will result in a bigger > patch. Besides the current way that seems to be the only reasonable place to do it. Pushing it into ->writepage also has the benefit that filesystems could piggy back the ctime update onto the transaction that updates the extent tree. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org