From: "Aneesh Kumar K.V" Subject: Re: Problem with delayed allocation Date: Mon, 4 Aug 2008 20:22:49 +0530 Message-ID: <20080804145249.GA9397@skywalker> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: "Theodore Ts'o" Return-path: Received: from E23SMTP05.au.ibm.com ([202.81.18.174]:41836 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752627AbYHDOxZ (ORCPT ); Mon, 4 Aug 2008 10:53:25 -0400 Received: from sd0109e.au.ibm.com (d23rh905.au.ibm.com [202.81.18.225]) by e23smtp05.au.ibm.com (8.13.1/8.13.1) with ESMTP id m74EqZon017766 for ; Tue, 5 Aug 2008 00:52:35 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by sd0109e.au.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m74ErMVa301600 for ; Tue, 5 Aug 2008 00:53:22 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m74ErMrf027400 for ; Tue, 5 Aug 2008 00:53:22 +1000 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sat, Aug 02, 2008 at 04:07:19PM -0400, Theodore Ts'o wrote: > > Apparently __fsync_super(), which is called right before remounting a > filesystem read-only, isn't working correctly. To reproduce, create a > script which does this: > > #!/bin/sh > DEVICE=/dev/closure/test > mke2fs -t ext4dev /dev/closure/test > mount $DEVICE /mnt > cd /mnt > tar xfj /var/tmp/linux-2.6.26.tar.gz <----- or some really big file > du -s > cd .. > mount -o remount,ro /mnt > sync > dmesg > /tmp/dmesg.out <----- note all of the ext4_da_writepages error messages > umount /mnt > du -s /mnt > sync > mount $DEVICE /mnt > du -s /mnt <--- note that size of the unpacked hierarcy is much smaller > > This doesn't happen if the ext4 filesystem is mounted with nodelalloc, > so I assume the problem is in ext4_da_writepages(). > Can you try this patch and see if it makes any difference ? diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 25adfc3..5a8a2d3 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -518,6 +518,7 @@ void generic_sync_sb_inodes(struct super_block *sb, spin_lock(&inode_lock); if (wbc->nr_to_write <= 0) { wbc->more_io = 1; + printk(KERN_CRIT "Breaking from the %s loop\n", __func__); break; } if (!list_empty(&sb->s_more_io)) @@ -611,6 +612,8 @@ void sync_inodes_sb(struct super_block *sb, int wait) (inodes_stat.nr_inodes - inodes_stat.nr_unused) + nr_dirty + nr_unstable; wbc.nr_to_write += wbc.nr_to_write / 2; /* Bit more for luck */ + wbc.nr_to_write = LONG_MAX; + sync_sb_inodes(sb, &wbc); }