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[2620:137:e000::1:20]) by mx.google.com with ESMTP id i17-20020a17090acf9100b0023d13eb5e5dsi765095pju.127.2023.03.16.18.54.01; Thu, 16 Mar 2023 18:54:14 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229644AbjCQBgv (ORCPT + 99 others); Thu, 16 Mar 2023 21:36:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229589AbjCQBgs (ORCPT ); Thu, 16 Mar 2023 21:36:48 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95D72A219B; Thu, 16 Mar 2023 18:36:46 -0700 (PDT) Received: from kwepemm600013.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Pd6DC0P6NzKmr8; Fri, 17 Mar 2023 09:36:27 +0800 (CST) Received: from huawei.com (10.175.127.227) by kwepemm600013.china.huawei.com (7.193.23.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Fri, 17 Mar 2023 09:36:42 +0800 From: Zhihao Cheng To: , , , CC: , , , Subject: [PATCH] ext4: Fix i_disksize exceeding i_size problem in paritally written case Date: Fri, 17 Mar 2023 09:35:53 +0800 Message-ID: <20230317013553.1009553-1-chengzhihao1@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600013.china.huawei.com (7.193.23.68) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760578034975823710?= X-GMAIL-MSGID: =?utf-8?q?1760578034975823710?= Following process makes i_disksize exceed i_size: generic_perform_write copied = iov_iter_copy_from_user_atomic(len) // copied < len ext4_da_write_end | ext4_update_i_disksize | new_i_size = pos + copied; | WRITE_ONCE(EXT4_I(inode)->i_disksize, newsize) // update i_disksize | generic_write_end | copied = block_write_end(copied, len) // copied = 0 | if (unlikely(copied < len)) | if (!PageUptodate(page)) | copied = 0; | if (pos + copied > inode->i_size) // return false if (unlikely(copied == 0)) goto again; if (unlikely(iov_iter_fault_in_readable(i, bytes))) { status = -EFAULT; break; } We get i_disksize greater than i_size here, which could trigger WARNING check 'i_size_read(inode) < EXT4_I(inode)->i_disksize' while doing dio: ext4_dio_write_iter iomap_dio_rw __iomap_dio_rw // return err, length is not aligned to 512 ext4_handle_inode_extension WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize) // Oops WARNING: CPU: 2 PID: 2609 at fs/ext4/file.c:319 CPU: 2 PID: 2609 Comm: aa Not tainted 6.3.0-rc2 RIP: 0010:ext4_file_write_iter+0xbc7 Call Trace: vfs_write+0x3b1 ksys_write+0x77 do_syscall_64+0x39 Fix it by putting block_write_end() before i_disksize updating just like ext4_write_end() does. Fetch a reproducer in [Link]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217209 Fixes: 64769240bd07f ("ext4: Add delayed allocation support in data=writeback mode") Signed-off-by: Zhihao Cheng --- fs/ext4/inode.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index bf0b7dea4900..577dc23f3b78 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3136,6 +3136,8 @@ static int ext4_da_write_end(struct file *file, loff_t new_i_size; unsigned long start, end; int write_mode = (int)(unsigned long)fsdata; + bool i_size_changed = false; + loff_t old_size = inode->i_size; if (write_mode == FALL_BACK_TO_NONDELALLOC) return ext4_write_end(file, mapping, pos, @@ -3148,6 +3150,8 @@ static int ext4_da_write_end(struct file *file, ext4_has_inline_data(inode)) return ext4_write_inline_data_end(inode, pos, len, copied, page); + copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); + start = pos & (PAGE_SIZE - 1); end = start + copied - 1; @@ -3162,16 +3166,30 @@ static int ext4_da_write_end(struct file *file, * check), we need to update i_disksize here as neither * ext4_writepage() nor certain ext4_writepages() paths not * allocating blocks update i_disksize. - * - * Note that we defer inode dirtying to generic_write_end() / - * ext4_da_write_inline_data_end(). */ new_i_size = pos + copied; - if (copied && new_i_size > inode->i_size && - ext4_da_should_update_i_disksize(page, end)) - ext4_update_i_disksize(inode, new_i_size); + if (new_i_size > inode->i_size) { + i_size_write(inode, new_i_size); + i_size_changed = true; + if (copied && ext4_da_should_update_i_disksize(page, end)) + ext4_update_i_disksize(inode, new_i_size); + } + + unlock_page(page); + put_page(page); + + if (old_size < pos) + pagecache_isize_extended(inode, old_size, pos); + /* + * Don't mark the inode dirty under page lock. First, it unnecessarily + * makes the holding time of page lock longer. Second, it forces lock + * ordering of page lock and transaction start for journaling + * filesystems. + */ + if (i_size_changed) + mark_inode_dirty(inode); - return generic_write_end(file, mapping, pos, len, copied, page, fsdata); + return copied; } /*