From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id n0KNORFi024099 for ; Tue, 20 Jan 2009 17:24:28 -0600 Received: from ipmail01.adl6.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 6DE13182CD39 for ; Tue, 20 Jan 2009 15:24:26 -0800 (PST) Received: from ipmail01.adl6.internode.on.net (ipmail01.adl6.internode.on.net [203.16.214.146]) by cuda.sgi.com with ESMTP id C473Tf6VLzkkfVWF for ; Tue, 20 Jan 2009 15:24:26 -0800 (PST) Date: Wed, 21 Jan 2009 10:24:22 +1100 From: Dave Chinner Subject: Re: spurious -ENOSPC on XFS Message-ID: <20090120232422.GF10158@disturbed> References: <20090113214949.GN8071@disturbed> <20090118173144.GA1999@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Mikulas Patocka Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, xfs@oss.sgi.com On Tue, Jan 20, 2009 at 02:38:27PM -0500, Mikulas Patocka wrote: > > > On Sun, 18 Jan 2009, Christoph Hellwig wrote: > > > On Tue, Jan 13, 2009 at 11:28:58PM -0500, Mikulas Patocka wrote: > > > The result must not depend on magic timer values. If it does, you end up > > > with undebbugable nondeterministic failures. > > > > > > Why don't you change that 500ms wait to "wait until the flush finishes"? > > > That would be correct. > > > > Yes, this probably would better. Could I motivate you to come up with > > a patch for that? > > > > Hi > > I looked at the source and found out that it uses sync_blockdev for > syncing --- but sync_blockdev writes only metadata buffers, it doesn't > touch inodes and pages and doesn't resolve delayed allocations. So it > really doesn't sync anything. Ah, bugger. Thanks for finding this. > I replaced it with correct syncing of all inodes. With this patch it > passes my testcase (no more spurious -ENOSPCs), but it still isn't > correct, there is that 500ms delay --- if the machine was so overloaded > that it couldn't sync withing 500ms, you still get spurious -ENOSPC. That's VFS level data syncing - there may be other XFS level stuff that can be dones as well (e.g. cleanup/truncate of unlinked inodes) that will release space. > There are notions about possible deadlocks (the syncer may lock against > the process that is waiting for the sync to finish), that's why removing > that 500ms delay isn't that easy as it seems. I don't have XFS knowledge > to check for the deadlocks, it should be done by XFS developers. Also, > when you resolve the deadlocks and drop the timeout, replace WB_SYNC_NONE > with WB_SYNC_ALL in this patch. Right, so you need to use internal xfs sync functions that don't have these problems. That is: error = xfs_sync_inodes(ip->i_mount, SYNC_DELWRI|SYNC_WAIT); will do a blocking flush of all the inodes without deadlocks occurring. Then you can remove the 500ms wait. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs