From patchwork Mon May 23 14:16:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 1634581 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4L6Jvx12LSz9sGl for ; Tue, 24 May 2022 00:03:41 +1000 (AEST) Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4L6Jvx0fn5z4xZ4 for ; Tue, 24 May 2022 00:03:41 +1000 (AEST) Received: by gandalf.ozlabs.org (Postfix) id 4L6Jvx0d3Vz4xZ5; Tue, 24 May 2022 00:03:41 +1000 (AEST) Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: gandalf.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4L6Jvx0NwXz4xZ4 for ; Tue, 24 May 2022 00:03:41 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236858AbiEWODh (ORCPT ); Mon, 23 May 2022 10:03:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236860AbiEWODa (ORCPT ); Mon, 23 May 2022 10:03:30 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E49F52E73; Mon, 23 May 2022 07:03:29 -0700 (PDT) Received: from dggpeml500020.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L6JrD0jkZzQk8X; Mon, 23 May 2022 22:00:28 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggpeml500020.china.huawei.com (7.185.36.88) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 22:03:26 +0800 From: Baokun Li To: CC: , , , , , , , , , , Hulk Robot Subject: [PATCH v2 1/2] ext4: fix bug_on ext4_mb_use_inode_pa Date: Mon, 23 May 2022 22:16:57 +0800 Message-ID: <20220523141658.2919003-2-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220523141658.2919003-1-libaokun1@huawei.com> References: <20220523141658.2919003-1-libaokun1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500020.china.huawei.com (7.185.36.88) 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,T_SCC_BODY_TEXT_LINE 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-ext4@vger.kernel.org Hulk Robot reported a BUG_ON: ================================================================== kernel BUG at fs/ext4/mballoc.c:3211! [...] RIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f [...] Call Trace: ext4_mb_new_blocks+0x9df/0x5d30 ext4_ext_map_blocks+0x1803/0x4d80 ext4_map_blocks+0x3a4/0x1a10 ext4_writepages+0x126d/0x2c30 do_writepages+0x7f/0x1b0 __filemap_fdatawrite_range+0x285/0x3b0 file_write_and_wait_range+0xb1/0x140 ext4_sync_file+0x1aa/0xca0 vfs_fsync_range+0xfb/0x260 do_fsync+0x48/0xa0 [...] ================================================================== Above issue may happen as follows: ------------------------------------- do_fsync vfs_fsync_range ext4_sync_file file_write_and_wait_range __filemap_fdatawrite_range do_writepages ext4_writepages mpage_map_and_submit_extent mpage_map_one_extent ext4_map_blocks ext4_mb_new_blocks ext4_mb_normalize_request >>> start + size <= ac->ac_o_ex.fe_logical ext4_mb_regular_allocator ext4_mb_simple_scan_group ext4_mb_use_best_found ext4_mb_new_preallocation ext4_mb_new_inode_pa ext4_mb_use_inode_pa >>> set ac->ac_b_ex.fe_len <= 0 ext4_mb_mark_diskspace_used >>> BUG_ON(ac->ac_b_ex.fe_len <= 0); we can easily reproduce this problem with the following commands: `fallocate -l100M disk` `mkfs.ext4 -b 1024 -g 256 disk` `mount disk /mnt` `fsstress -d /mnt -l 0 -n 1000 -p 1` The size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP. Therefore, "start + size <= ac->ac_o_ex.fe_logical" may occur when the size is truncated. So start should be the start position of the group where ac_o_ex.fe_logical is located after alignment. In addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP is very large, the value calculated by start_off is more accurate. Fixes: cd648b8a8fd5 ("ext4: trim allocation requests to group size") Reported-by: Hulk Robot Signed-off-by: Baokun Li Reported-by: kernel test robot Reported-by: kernel test robot --- V1->V2: Replace round_down() with rounddown(). Modified comments. fs/ext4/mballoc.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 9f12f29bc346..6aafc242fe23 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4104,6 +4104,15 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, size = size >> bsbits; start = start_off >> bsbits; + /* + * For tiny groups (smaller than 8MB) the chosen allocation + * alignment may be larger than group size. Make sure the + * alignment does not move allocation to a different group which + * makes mballoc fail assertions later. + */ + start = max(start, rounddown(ac->ac_o_ex.fe_logical, + EXT4_BLOCKS_PER_GROUP(ac->ac_sb))); + /* don't cover already allocated blocks in selected range */ if (ar->pleft && start <= ar->lleft) { size -= ar->lleft + 1 - start;