From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C67D8C43603 for ; Fri, 13 Dec 2019 09:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9BE4C22527 for ; Fri, 13 Dec 2019 09:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725906AbfLMJht (ORCPT ); Fri, 13 Dec 2019 04:37:49 -0500 Received: from mx2.suse.de ([195.135.220.15]:40392 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725793AbfLMJht (ORCPT ); Fri, 13 Dec 2019 04:37:49 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 5CE64AF84; Fri, 13 Dec 2019 09:37:47 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 9546D1E0CAF; Fri, 13 Dec 2019 10:37:46 +0100 (CET) Date: Fri, 13 Dec 2019 10:37:46 +0100 From: Jan Kara To: yangerkun Cc: tytso@mit.edu, jack@suse.cz, linux-ext4@vger.kernel.org, yi.zhang@huawei.com, houtao1@huawei.com Subject: Re: [PATCH] ext4: reserve revoke credits in __ext4_new_inode Message-ID: <20191213093746.GA15331@quack2.suse.cz> References: <20191213014900.47228-1-yangerkun@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191213014900.47228-1-yangerkun@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Fri 13-12-19 09:49:00, yangerkun wrote: > It's possible that __ext4_new_inode will release the xattr block, so > it will trigger a warning since there is revoke credits will be 0 if > the handle == NULL. The below scripts can reproduce it easily. > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 3861 at fs/jbd2/revoke.c:374 jbd2_journal_revoke+0x30e/0x540 fs/jbd2/revoke.c:374 > ... > __ext4_forget+0x1d7/0x800 fs/ext4/ext4_jbd2.c:248 > ext4_free_blocks+0x213/0x1d60 fs/ext4/mballoc.c:4743 > ext4_xattr_release_block+0x55b/0x780 fs/ext4/xattr.c:1254 > ext4_xattr_block_set+0x1c2c/0x2c40 fs/ext4/xattr.c:2112 > ext4_xattr_set_handle+0xa7e/0x1090 fs/ext4/xattr.c:2384 > __ext4_set_acl+0x54d/0x6c0 fs/ext4/acl.c:214 > ext4_init_acl+0x218/0x2e0 fs/ext4/acl.c:293 > __ext4_new_inode+0x352a/0x42b0 fs/ext4/ialloc.c:1151 > ext4_mkdir+0x2e9/0xbd0 fs/ext4/namei.c:2774 > vfs_mkdir+0x386/0x5f0 fs/namei.c:3811 > do_mkdirat+0x11c/0x210 fs/namei.c:3834 > do_syscall_64+0xa1/0x530 arch/x86/entry/common.c:294 > ... > ------------------------------------- > > scripts: > mkfs.ext4 /dev/vdb > mount /dev/vdb /mnt > cd /mnt && mkdir dir && for i in {1..8}; do setfacl -dm "u:user_"$i":rx" dir; done > mkdir dir/dir1 && mv dir/dir1 ./ > sh repro.sh && add some user > > [root@localhost ~]# cat repro.sh > while [ 1 -eq 1 ]; do > rm -rf dir > rm -rf dir1/dir1 > mkdir dir > for i in {1..8}; do setfacl -dm "u:test"$i":rx" dir; done > setfacl -m "u:user_9:rx" dir & > mkdir dir1/dir1 & > done > > Before exec repro.sh, dir1 has inherit the default acl from dir, and > xattr block of dir1 dir is not the same, so the h_refcount of these > two dir's xattr block will be 1. Then repro.sh can trigger the warning > with the situation show as below. The last h_refcount can be clear > with mkdir, and __ext4_new_inode has not reserved revoke credits, so > the warning will happened, fix it by reserve revoke credits in > __ext4_new_inode. > > Thread 1 Thread 2 > mkdir dir > set default acl(will create > a xattr block blk1 and the > refcount of ext4_xattr_header > will be 1) > ... > mkdir dir1/dir1 > ->....->ext4_init_acl > ->__ext4_set_acl(set default acl, > will reuse blk1, and h_refcount > will be 2) > > setfacl->ext4_set_acl->... > ->ext4_xattr_block_set(will create > new block blk2 to store xattr) > > ->__ext4_set_acl(set access acl, since > h_refcount of blk1 is 2, will create > blk3 to store xattr) > > ->ext4_xattr_release_block(dec > h_refcount of blk1 to 1) > ->ext4_xattr_release_block(dec > h_refcount and since it is 0, > will release the block and trigger > the warning) > > Reported-by: Hulk Robot > Signed-off-by: yangerkun Subtle. Thanks for debugging this! The patch looks good to me. You can add: Reviewed-by: Jan Kara Honza > --- > fs/ext4/ialloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c > index dc333e8e51e8..8ca4a23129aa 100644 > --- a/fs/ext4/ialloc.c > +++ b/fs/ext4/ialloc.c > @@ -921,8 +921,8 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, > if (!handle) { > BUG_ON(nblocks <= 0); > handle = __ext4_journal_start_sb(dir->i_sb, line_no, > - handle_type, nblocks, > - 0, 0); > + handle_type, nblocks, 0, > + ext4_trans_default_revoke_credits(sb)); > if (IS_ERR(handle)) { > err = PTR_ERR(handle); > ext4_std_error(sb, err); > -- > 2.17.2 > -- Jan Kara SUSE Labs, CR