From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762548AbXKTS3o (ORCPT ); Tue, 20 Nov 2007 13:29:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758695AbXKTS0e (ORCPT ); Tue, 20 Nov 2007 13:26:34 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:60254 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761473AbXKTS0c (ORCPT ); Tue, 20 Nov 2007 13:26:32 -0500 Date: Tue, 20 Nov 2007 10:23:34 -0800 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@kernel.org, torvalds@linux-foundation.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, maximlevitsky@gmail.com, peterz@infradead.org, jeffm@suse.com, wfg@mail.ustc.edu.cn, chris.mason@oracle.com Subject: [patch 11/29] reiserfs: dont drop PG_dirty when releasing sub-page-sized dirty file Message-ID: <20071120182334.GL28611@kroah.com> References: <20071120181733.702234406@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="reiserfs-don-t-drop-pg_dirty-when-releasing-sub-page-sized-dirty-file.patch" In-Reply-To: <20071120182248.GA28611@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 2.6.23-stable review patch. If anyone has any objections, please let us know. ------------------ From: Fengguang Wu patch c06a018fa5362fa9ed0768bd747c0fab26bc8849 in mainline. This is not a new problem in 2.6.23-git17. 2.6.22/2.6.23 is buggy in the same way. Reiserfs could accumulate dirty sub-page-size files until umount time. They cannot be synced to disk by pdflush routines or explicit `sync' commands. Only `umount' can do the trick. The direct cause is: the dirty page's PG_dirty is wrongly _cleared_. Call trace: [] cancel_dirty_page+0xd0/0xf0 [] :reiserfs:reiserfs_cut_from_item+0x660/0x710 [] :reiserfs:reiserfs_do_truncate+0x271/0x530 [] :reiserfs:reiserfs_truncate_file+0xfd/0x3b0 [] :reiserfs:reiserfs_file_release+0x1e0/0x340 [] __fput+0xcc/0x1b0 [] fput+0x16/0x20 [] filp_close+0x56/0x90 [] sys_close+0xad/0x110 [] system_call+0x7e/0x83 Fix the bug by removing the cancel_dirty_page() call. Tests show that it causes no bad behaviors on various write sizes. === for the patient === Here are more detailed demonstrations of the problem. 1) the page has both PG_dirty(D)/PAGECACHE_TAG_DIRTY(d) after being written to; and then only PAGECACHE_TAG_DIRTY(d) remains after the file is closed. ------------------------------ screen 0 ------------------------------ [T0] root /home/wfg# cat > /test/tiny [T1] hi [T2] root /home/wfg# ------------------------------ screen 1 ------------------------------ [T1] root /home/wfg# echo /test/tiny > /proc/filecache [T1] root /home/wfg# cat /proc/filecache # file /test/tiny # flags R:referenced A:active M:mmap U:uptodate D:dirty W:writeback O:owner B:buffer d:dirty w:writeback # idx len state refcnt 0 1 ___UD__Bd_ 2 [T2] root /home/wfg# cat /proc/filecache # file /test/tiny # flags R:referenced A:active M:mmap U:uptodate D:dirty W:writeback O:owner B:buffer d:dirty w:writeback # idx len state refcnt 0 1 ___U___Bd_ 2 2) note the non-zero 'cancelled_write_bytes' after /tmp/hi is copied. ------------------------------ screen 0 ------------------------------ [T0] root /home/wfg# echo hi > /tmp/hi [T1] root /home/wfg# cp /tmp/hi /dev/stdin /test [T2] hi [T3] root /home/wfg# ------------------------------ screen 1 ------------------------------ [T1] root /proc/4397# cd /proc/`pidof cp` [T1] root /proc/4713# cat io rchar: 8396 wchar: 3 syscr: 20 syscw: 1 read_bytes: 0 write_bytes: 20480 cancelled_write_bytes: 4096 [T2] root /proc/4713# cat io rchar: 8399 wchar: 6 syscr: 21 syscw: 2 read_bytes: 0 write_bytes: 24576 cancelled_write_bytes: 4096 //Question: the 'write_bytes' is a bit more than expected ;-) Tested-by: Maxim Levitsky Cc: Peter Zijlstra Cc: Jeff Mahoney Signed-off-by: Fengguang Wu Reviewed-by: Chris Mason Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/reiserfs/stree.c | 3 --- 1 file changed, 3 deletions(-) --- a/fs/reiserfs/stree.c +++ b/fs/reiserfs/stree.c @@ -1458,9 +1458,6 @@ static void unmap_buffers(struct page *p } bh = next; } while (bh != head); - if (PAGE_SIZE == bh->b_size) { - cancel_dirty_page(page, PAGE_CACHE_SIZE); - } } } } --