From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH] writeback: Don't wait for completion in writeback_inodes_sb_nr Date: Thu, 30 Jun 2011 14:15:58 +0200 Message-ID: <20110630121558.GF28475@quack.suse.cz> References: <1309304616-8657-1-git-send-email-curtw@google.com> <20110629005422.GQ32466@dastard> <20110629081155.GA5558@infradead.org> <20110629165714.GF17590@quack.suse.cz> <20110629175534.GA32236@infradead.org> <20110629191518.GA23196@quack.suse.cz> <20110629201234.GA31129@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Curt Wohlgemuth , Al Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, fengguang.wu@intel.com To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20110629201234.GA31129@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed 29-06-11 16:12:34, Christoph Hellwig wrote: > On Wed, Jun 29, 2011 at 09:15:18PM +0200, Jan Kara wrote: > > True but writeback_single_inode() has in it: > > if (wbc->sync_mode == WB_SYNC_ALL) { > > int err = filemap_fdatawait(mapping); > > if (ret == 0) > > ret = err; > > } > > So we end up waiting much earlier. Probably we should remove this wait > > but that will need some audit I guess. > > Uhh, indeed. We'll need this wait for things like sync_inode, though. Yes. Actually, specifically for filesystems like XFS which update inode after IO completion we would need more passes to be efficient and correct: for all inodes fdatawrite for all inodes fdatawait for all inodes write_inode for all inodes wait for inode IO But maybe this could be handled by having new WB_SYNC_ mode indicating that writeback_single_inode() should not bother waiting (thus we'd really end up waiting in sync_inodes_sb()) and then XFS and other filesystems that need it would writeout inodes in their sync_fs() implementation (possibly using a generic helper)? Honza -- Jan Kara SUSE Labs, CR