From: Christoph Hellwig Subject: Re: [PATCH 3/3] filemap: don't call generic_write_sync for -EIOCBQUEUED Date: Mon, 6 Feb 2012 14:55:47 -0500 Message-ID: <20120206195546.GA22640@infradead.org> References: <1327698949-12616-1-git-send-email-jmoyer@redhat.com> <1327698949-12616-4-git-send-email-jmoyer@redhat.com> <20120202175219.GB6640@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com To: Jeff Moyer Return-path: Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:56863 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752841Ab2BFTzt (ORCPT ); Mon, 6 Feb 2012 14:55:49 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Feb 06, 2012 at 11:33:29AM -0500, Jeff Moyer wrote: > > code, right? Before that we'd drain the IO queue when cache flush is issued > > and thus effectively wait for IO completion... > > Right, though hch seems to think even then the problem existed. I was wrong, using -o barrier it didn't. That was however not something people using O_SYNC heavy production loads would do, they'd use disabled caches and nobarrier. > > Also I was thinking whether we couldn't implement the fix in VFS. Basically > > it would be the same like the fix for ext4. Like having a per-sb workqueue > > and queue work calling generic_write_sync() from end_io handler when the > > file is O_SYNC? That would solve the issue for all filesystems... > > Well, that would require buy-in from the other file system developers. > What do the XFS folks think? I don't think using that code for XFS makes sene. But just like generic_write_sync there's no reason it can't be added to generic code, just make sure only generic_file_aio_write/__generic_file_aio_write use it, but generic_file_buffered_write and generic_file_direct_write stay clear of it.