From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753819AbdCTLHL (ORCPT ); Mon, 20 Mar 2017 07:07:11 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:4342 "EHLO dggrg02-dlp.huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753497AbdCTLGd (ORCPT ); Mon, 20 Mar 2017 07:06:33 -0400 Subject: Re: [PATCH] f2fs: protect free nid operation with cp_rwsem To: Jaegeuk Kim References: <20170317104623.90116-1-yuchao0@huawei.com> <20170319224426.GA45667@jaegeuk.local> CC: , , From: Chao Yu Message-ID: Date: Mon, 20 Mar 2017 19:06:02 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <20170319224426.GA45667@jaegeuk.local> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090202.58CFB79E.0424,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 0aaeda816d07584dac40e1b0c12af190 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jaegeuk, On 2017/3/20 6:44, Jaegeuk Kim wrote: > Hi Chao, > > On 03/17, Chao Yu wrote: >> - f2fs_balance_fs_bg >> - build_free_ni >> - __build_free_nids >> - scan_nat_page >> - add_free_nid >> - f2fs_create >> - f2fs_new_inode >> - alloc_nid >> - remove_free_nid >> >> This patch uses cp_rwsem to protect free nid allocation/initialization >> to avoid reusing allocated nid in above scenario. > > It looks like description doesn't match to your change below? It looks like the problem will not happen because on_build_free_nids will stop alloc_nid stealing one allocated nid while building free nids. Please ignore this patch, sorry. I found another potential case, could you please check that one? Thanks, > > Thanks, > >> >> Signed-off-by: Chao Yu >> --- >> fs/f2fs/inode.c | 2 ++ >> fs/f2fs/segment.c | 5 ++++- >> 2 files changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c >> index 2520fa72b23f..f941410f994a 100644 >> --- a/fs/f2fs/inode.c >> +++ b/fs/f2fs/inode.c >> @@ -423,7 +423,9 @@ void f2fs_evict_inode(struct inode *inode) >> add_ino_entry(sbi, inode->i_ino, UPDATE_INO); >> } >> if (is_inode_flag_set(inode, FI_FREE_NID)) { >> + f2fs_lock_op(sbi); >> alloc_nid_failed(sbi, inode->i_ino); >> + f2fs_unlock_op(sbi); >> clear_inode_flag(inode, FI_FREE_NID); >> } >> f2fs_bug_on(sbi, err && >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index 0bf024f62330..f85e1f443c99 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -426,8 +426,11 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi) >> >> if (!available_free_memory(sbi, FREE_NIDS)) >> try_to_free_nids(sbi, MAX_FREE_NIDS); >> - else >> + else { >> + f2fs_lock_op(sbi); >> build_free_nids(sbi, false, false); >> + f2fs_unlock_op(sbi); >> + } >> >> if (!is_idle(sbi)) >> return; >> -- >> 2.8.2.295.g3f1c1d0 > > . >