From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (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 C144613AA49 for ; Tue, 27 Feb 2024 13:14:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709039668; cv=none; b=AOLyaOvh4z3kG3bhjX5shsrCfZJHVs+U7Zro2SveyB8FxGfe9WJ1jIkX069Zd6uevG8EtxkhGfkIPQDtjK49ENasAZNkrBQh0ug8Bw0z0hLWiORyzXD9+uO3iguMo1qfhfvi3ztFXljonKDqVQ+1L+eRxSpPXt+KIOKVPZHKiKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709039668; c=relaxed/simple; bh=icCF5R/d7qJgqcVDEV9xiQ6fGw0+7Bz+kaH+LFhauIQ=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HBL3KBT0xZ4Ddj3Y3gFp/ABvypPFq5+z+yO+X9Gct8TWQTFE/y2O0GACB0Dbm7xgtehbA2Ue1R+UWdkLcK76hWGSGaACnaygV0XjKFYsgNUBD2KzzWVJZnICAKx40vqL1fMafE99xx519FXltbt8veOMaw7jExiVDakP9Wuqowc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.190 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 [172.19.88.214]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4TkdFf3sFHz1xnfc; Tue, 27 Feb 2024 21:12:54 +0800 (CST) Received: from dggpeml500021.china.huawei.com (unknown [7.185.36.21]) by mail.maildlp.com (Postfix) with ESMTPS id B753D1A016B; Tue, 27 Feb 2024 21:14:23 +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_256_GCM_SHA384) id 15.1.2507.35; Tue, 27 Feb 2024 21:14:23 +0800 From: Baokun Li To: CC: , , , , , , , Subject: [PATCH 5.10 2/2] ext4: avoid bb_free and bb_fragments inconsistency in mb_free_blocks() Date: Tue, 27 Feb 2024 21:16:09 +0800 Message-ID: <20240227131609.898377-2-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20240227131609.898377-1-libaokun1@huawei.com> References: <20240227131609.898377-1-libaokun1@huawei.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500021.china.huawei.com (7.185.36.21) commit 2331fd4a49864e1571b4f50aa3aa1536ed6220d0 upstream. 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: # 3.10 Suggested-by: Jan Kara Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240104142040.2835097-5-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Baokun Li --- fs/ext4/mballoc.c | 39 +++++++++++++++++++++------------------ 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5799706e20cc..0a0a1118414a 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1494,11 +1494,6 @@ 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 */ @@ -1512,23 +1507,31 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, struct ext4_sb_info *sbi = EXT4_SB(sb); ext4_fsblk_t blocknr; + /* + * Fastcommit replay can free already freed blocks which + * corrupts allocation info. Regenerate it. + */ + if (sbi->s_mount_state & EXT4_FC_REPLAY) { + mb_regenerate_buddy(e4b); + goto check; + } + blocknr = ext4_group_first_block_no(sb, e4b->bd_group); blocknr += EXT4_C2B(sbi, block); - if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) { - ext4_grp_locked_error(sb, e4b->bd_group, - inode ? inode->i_ino : 0, - blocknr, - "freeing already freed block (bit %u); block bitmap corrupt.", - block); - ext4_mark_group_bitmap_corrupted( - sb, e4b->bd_group, + ext4_grp_locked_error(sb, e4b->bd_group, + inode ? inode->i_ino : 0, blocknr, + "freeing already freed block (bit %u); block bitmap corrupt.", + block); + ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, EXT4_GROUP_INFO_BBITMAP_CORRUPT); - } else { - mb_regenerate_buddy(e4b); - } - 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--; @@ -1553,8 +1556,8 @@ 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); +check: mb_check_buddy(e4b); } -- 2.31.1