From patchwork Thu Dec 21 15:05:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 1879204 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org (client-ip=150.107.74.76; helo=gandalf.ozlabs.org; envelope-from=srs0=kfbc=ia=vger.kernel.org=linux-ext4+bounces-538-patchwork-incoming=ozlabs.org@ozlabs.org; receiver=patchwork.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 ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4SwtxS065mz1ySd for ; Fri, 22 Dec 2023 02:04:12 +1100 (AEDT) Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4SwtxR6mkFz4wcX for ; Fri, 22 Dec 2023 02:04:11 +1100 (AEDT) Received: by gandalf.ozlabs.org (Postfix) id 4SwtxR6Xxsz4wd4; Fri, 22 Dec 2023 02:04:11 +1100 (AEDT) Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: gandalf.ozlabs.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: gandalf.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=147.75.48.161; helo=sy.mirrors.kernel.org; envelope-from=linux-ext4+bounces-538-patchwork-incoming=ozlabs.org@vger.kernel.org; receiver=ozlabs.org) Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org [147.75.48.161]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by gandalf.ozlabs.org (Postfix) with ESMTPS id 4SwtxR6Flrz4wcX for ; Fri, 22 Dec 2023 02:04:11 +1100 (AEDT) Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id 6E12FB235BC for ; Thu, 21 Dec 2023 15:04:11 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7F3505821E; Thu, 21 Dec 2023 15:02:50 +0000 (UTC) X-Original-To: linux-ext4@vger.kernel.org Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B021955E71; Thu, 21 Dec 2023 15:02:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Swttc05bVzvSHn; Thu, 21 Dec 2023 23:01:44 +0800 (CST) Received: from dggpeml500021.china.huawei.com (unknown [7.185.36.21]) by mail.maildlp.com (Postfix) with ESMTPS id B490C180069; Thu, 21 Dec 2023 23:02:39 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Thu, 21 Dec 2023 23:02:39 +0800 From: Baokun Li To: CC: , , , , , , , , , Subject: [PATCH v2 4/8] ext4: avoid bb_free and bb_fragments inconsistency in mb_free_blocks() Date: Thu, 21 Dec 2023 23:05:54 +0800 Message-ID: <20231221150558.2740823-5-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20231221150558.2740823-1-libaokun1@huawei.com> References: <20231221150558.2740823-1-libaokun1@huawei.com> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500021.china.huawei.com (7.185.36.21) After updating bb_free in mb_free_blocks, it is possible to return without updating bb_fragments because the block being freed is found to have already been freed, which leads to inconsistency between bb_free and bb_fragments. Since the group may be unlocked in ext4_grp_locked_error(), this can lead to problems such as dividing by zero when calculating the average fragment length. Hence move the update of bb_free to after the block double-free check guarantees that the corresponding statistics are updated only after the core block bitmap is modified. Fixes: eabe0444df90 ("ext4: speed-up releasing blocks on commit") CC: stable@vger.kernel.org # 3.10 Signed-off-by: Baokun Li Reviewed-by: Jan Kara --- fs/ext4/mballoc.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index f6131ba514c8..1f15774971d7 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1910,11 +1910,6 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, mb_check_buddy(e4b); mb_free_blocks_double(inode, e4b, first, count); - this_cpu_inc(discard_pa_seq); - e4b->bd_info->bb_free += count; - if (first < e4b->bd_info->bb_first_free) - e4b->bd_info->bb_first_free = first; - /* access memory sequentially: check left neighbour, * clear range and then check right neighbour */ @@ -1941,10 +1936,16 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, EXT4_GROUP_INFO_BBITMAP_CORRUPT); } else { mb_regenerate_buddy(e4b); + goto check; } - goto done; + return; } + this_cpu_inc(discard_pa_seq); + e4b->bd_info->bb_free += count; + if (first < e4b->bd_info->bb_first_free) + e4b->bd_info->bb_first_free = first; + /* let's maintain fragments counter */ if (left_is_free && right_is_free) e4b->bd_info->bb_fragments--; @@ -1969,9 +1970,9 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, if (first <= last) mb_buddy_mark_free(e4b, first >> 1, last >> 1); -done: mb_set_largest_free_order(sb, e4b->bd_info); mb_update_avg_fragment_size(sb, e4b->bd_info); +check: mb_check_buddy(e4b); }