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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3AFAC433EF for ; Fri, 25 Feb 2022 10:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236440AbiBYKNm (ORCPT ); Fri, 25 Feb 2022 05:13:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230206AbiBYKNk (ORCPT ); Fri, 25 Feb 2022 05:13:40 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05CC5C7D70 for ; Fri, 25 Feb 2022 02:13:07 -0800 (PST) Received: from canpemm500005.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4K4lpm37Y1zbbvS; Fri, 25 Feb 2022 18:08:32 +0800 (CST) Received: from huawei.com (10.175.127.227) by canpemm500005.china.huawei.com (7.192.104.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 25 Feb 2022 18:13:05 +0800 From: Zhang Yi To: CC: , , , , Subject: [PATCH v2] ext4: fix underflow in ext4_max_bitmap_size() Date: Fri, 25 Feb 2022 18:28:37 +0800 Message-ID: <20220225102837.3048196-1-yi.zhang@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500005.china.huawei.com (7.192.104.229) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org The same to commit 1c2d14212b15 ("ext2: Fix underflow in ext2_max_size()") in ext2 filesystem, ext4 driver has the same issue with 64K block size and ^huge_file, fix this issue the same as ext2. This patch also revert commit 75ca6ad408f4 ("ext4: fix loff_t overflow in ext4_max_bitmap_size()") because it's no longer needed. Signed-off-by: Zhang Yi --- v2->v1: use DIV_ROUND_UP_ULL instead of DIV_ROUND_UP. fs/ext4/super.c | 46 +++++++++++++++++++++++++++++++--------------- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index c5021ca0a28a..95608c2127e7 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3468,8 +3468,9 @@ static loff_t ext4_max_size(int blkbits, int has_huge_files) */ static loff_t ext4_max_bitmap_size(int bits, int has_huge_files) { - unsigned long long upper_limit, res = EXT4_NDIR_BLOCKS; + loff_t upper_limit, res = EXT4_NDIR_BLOCKS; int meta_blocks; + unsigned int ppb = 1 << (bits - 2); /* * This is calculated to be the largest file size for a dense, block @@ -3501,27 +3502,42 @@ static loff_t ext4_max_bitmap_size(int bits, int has_huge_files) } - /* indirect blocks */ - meta_blocks = 1; - /* double indirect blocks */ - meta_blocks += 1 + (1LL << (bits-2)); - /* tripple indirect blocks */ - meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2))); - - upper_limit -= meta_blocks; - upper_limit <<= bits; - + /* Compute how many blocks we can address by block tree */ res += 1LL << (bits-2); res += 1LL << (2*(bits-2)); res += 1LL << (3*(bits-2)); + /* Compute how many metadata blocks are needed */ + meta_blocks = 1; + meta_blocks += 1 + ppb; + meta_blocks += 1 + ppb + ppb * ppb; + /* Does block tree limit file size? */ + if (res + meta_blocks <= upper_limit) + goto check_lfs; + + res = upper_limit; + /* How many metadata blocks are needed for addressing upper_limit? */ + upper_limit -= EXT4_NDIR_BLOCKS; + /* indirect blocks */ + meta_blocks = 1; + upper_limit -= ppb; + /* double indirect blocks */ + if (upper_limit < ppb * ppb) { + meta_blocks += 1 + DIV_ROUND_UP_ULL(upper_limit, ppb); + res -= meta_blocks; + goto check_lfs; + } + meta_blocks += 1 + ppb; + upper_limit -= ppb * ppb; + /* tripple indirect blocks for the rest */ + meta_blocks += 1 + DIV_ROUND_UP_ULL(upper_limit, ppb) + + DIV_ROUND_UP_ULL(upper_limit, ppb*ppb); + res -= meta_blocks; +check_lfs: res <<= bits; - if (res > upper_limit) - res = upper_limit; - if (res > MAX_LFS_FILESIZE) res = MAX_LFS_FILESIZE; - return (loff_t)res; + return res; } static ext4_fsblk_t descriptor_loc(struct super_block *sb, -- 2.31.1