From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965334Ab1KJDl1 (ORCPT ); Wed, 9 Nov 2011 22:41:27 -0500 Received: from cantor2.suse.de ([195.135.220.15]:44274 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965315Ab1KJDlV (ORCPT ); Wed, 9 Nov 2011 22:41:21 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Nov 9 13:31:51 2011 Message-Id: <20111109213151.423427751@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 09 Nov 2011 13:32:20 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Peng Tao , Jim Rees , Trond Myklebust Subject: [093/264] pnfsblock: fix writeback deadlock In-Reply-To: <20111109213508.GA3476@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peng Tao commit 7542274519b3ba87555410c66e8356ac1e3bc9b3 upstream. We should check if the sector is already initialized before trying to grab the page from page cache. Otherwise when two pages of the same block are written back by two threads each calling from writepage_locked, it can cause deadlock like bellow. [ 1080.972099] INFO: task kswapd0:25 blocked for more than 120 seconds. [ 1080.972377] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1080.972812] kswapd0 D ffff88000c4926c0 0 25 2 0x00000000 [ 1080.972816] ffff88000df276b0 0000000000000046 ffff88000df27640 ffffffff81013ba7 [ 1080.972821] ffff88000c492310 ffff88000df27fd8 ffff88000df27fd8 00000000001d3440 [ 1080.972824] ffff88000c378000 ffff88000c492310 ffff8800175d3d40 ffff880017fc75a8 [ 1080.972828] Call Trace: [ 1080.972860] [] ? read_tsc+0x9/0x19 [ 1080.972877] [] ? lock_page+0x2b/0x2b [ 1080.972899] [] io_schedule+0x63/0x7e [ 1080.972902] [] sleep_on_page+0xe/0x12 [ 1080.972905] [] __wait_on_bit_lock+0x46/0x8f [ 1080.972916] [] ? lock_release_holdtime.part.7+0x6b/0x72 [ 1080.972919] [] __lock_page+0x66/0x68 [ 1080.972928] [] ? autoremove_wake_function+0x3d/0x3d [ 1080.972932] [] lock_page+0x27/0x2b [ 1080.972934] [] find_lock_page+0x34/0x57 [ 1080.972937] [] find_or_create_page+0x34/0x8a [ 1080.972947] [] bl_write_pagelist+0x205/0x6da [blocklayoutdriver] [ 1080.972951] [] ? bl_free_lseg+0x38/0x38 [blocklayoutdriver] [ 1080.972995] [] ? nfs_write_rpcsetup+0x118/0x123 [nfs] [ 1080.973033] [] pnfs_generic_pg_writepages+0x10b/0x1f4 [nfs] [ 1080.973089] [] nfs_pageio_doio+0x1a/0x43 [nfs] [ 1080.973098] [] nfs_pageio_complete+0x16/0x2d [nfs] [ 1080.973108] [] nfs_writepage_locked+0xa0/0xbf [nfs] [ 1080.973119] [] nfs_writepage+0x16/0x2b [nfs] [ 1080.973122] [] ? clear_page_dirty_for_io+0x87/0x9a [ 1080.973133] [] shrink_page_list+0x39b/0x6c8 [ 1080.973139] [] shrink_inactive_list+0x22c/0x39e [ 1080.973144] [] ? lock_release_holdtime.part.7+0x6b/0x72 [ 1080.973148] [] shrink_zone+0x445/0x588 [ 1080.973152] [] balance_pgdat+0x2c2/0x56b [ 1080.973170] [] ? __bitmap_weight+0x34/0x80 [ 1080.973175] [] kswapd+0x2be/0x2fa [ 1080.973179] [] ? __init_waitqueue_head+0x4b/0x4b [ 1080.973183] [] ? balance_pgdat+0x56b/0x56b [ 1080.973187] [] kthread+0xa8/0xb0 [ 1080.973200] [] kernel_thread_helper+0x4/0x10 [ 1080.973205] [] ? __init_kthread_worker+0x5a/0x5a [ 1080.973210] [] ? gs_change+0x13/0x13 [ 1080.973213] no locks held by kswapd0/25. Signed-off-by: Peng Tao Signed-off-by: Jim Rees Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/nfs/blocklayout/blocklayout.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/fs/nfs/blocklayout/blocklayout.c +++ b/fs/nfs/blocklayout/blocklayout.c @@ -533,6 +533,11 @@ bl_write_pagelist(struct nfs_write_data fill_invalid_ext: dprintk("%s need to zero %d pages\n", __func__, npg_zero); for (;npg_zero > 0; npg_zero--) { + if (bl_is_sector_init(be->be_inval, isect)) { + dprintk("isect %llu already init\n", + (unsigned long long)isect); + goto next_page; + } /* page ref released in bl_end_io_write_zero */ index = isect >> PAGE_CACHE_SECTOR_SHIFT; dprintk("%s zero %dth page: index %lu isect %llu\n", @@ -552,8 +557,7 @@ fill_invalid_ext: * PageUptodate: It was read before * sector_initialized: already written out */ - if (PageDirty(page) || PageWriteback(page) || - bl_is_sector_init(be->be_inval, isect)) { + if (PageDirty(page) || PageWriteback(page)) { print_page(page); unlock_page(page); page_cache_release(page);