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 D9ECEC001DB for ; Thu, 3 Aug 2023 15:02:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236128AbjHCPCc (ORCPT ); Thu, 3 Aug 2023 11:02:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235774AbjHCPCb (ORCPT ); Thu, 3 Aug 2023 11:02:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63263198A; Thu, 3 Aug 2023 08:02:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (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 dfw.source.kernel.org (Postfix) with ESMTPS id EA4E261DEC; Thu, 3 Aug 2023 15:02:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A1C6C433C8; Thu, 3 Aug 2023 15:02:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691074949; bh=eJG2y8lWiM9+Gm8twe05n+s2uPVK+OJcTkp9+x5uPx8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fXb/3dayOF5xVdmMG+rCWicLUQZ9tzAxLytSwZQdkPanPjKKeEA1MpLAibwOGh/GG t6QHQOvrTtBBBYzdubk+5pCYf0KJrAyaXhLGg/QwO/k/muIydUFJRJWiLzp6848jVG LCoWRGSNbGmHbmLGTBa4j+Gnz0ogfdVQfqcpE5kTMAF+ZxK6inJhdoa2Rawa48/xpA vrzh6+RxKL1tL8up2BLJV0P8GX4sRVnW/tvkOaIPLTd4BcQ7jD0QOY+6oJW8RV1EaP VYnKMCVnYeMYtz96HOf9akhzggBzBRp+JmJSkALVOzAE+QTZMWgf5MzDgnrvkEaMay CiWq9ivDf8bGw== Date: Thu, 3 Aug 2023 08:02:28 -0700 From: "Darrick J. Wong" To: zhangshida Cc: tytso@mit.edu, adilger.kernel@dilger.ca, yi.zhang@huawei.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, zhangshida@kylinos.cn, stable@kernel.org, Andreas Dilger Subject: Re: [PATCH v4] ext4: Fix rec_len verify error Message-ID: <20230803150228.GC11332@frogsfrogsfrogs> References: <20230803060938.1929759-1-zhangshida@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230803060938.1929759-1-zhangshida@kylinos.cn> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Thu, Aug 03, 2023 at 02:09:38PM +0800, zhangshida wrote: > From: Shida Zhang > > With the configuration PAGE_SIZE 64k and filesystem blocksize 64k, > a problem occurred when more than 13 million files were directly created > under a directory: > > EXT4-fs error (device xx): ext4_dx_csum_set:492: inode #xxxx: comm xxxxx: dir seems corrupt? Run e2fsck -D. > EXT4-fs error (device xx): ext4_dx_csum_verify:463: inode #xxxx: comm xxxxx: dir seems corrupt? Run e2fsck -D. > EXT4-fs error (device xx): dx_probe:856: inode #xxxx: block 8188: comm xxxxx: Directory index failed checksum > > When enough files are created, the fake_dirent->reclen will be 0xffff. > it doesn't equal to the blocksize 65536, i.e. 0x10000. > > But it is not the same condition when blocksize equals to 4k. > when enough files are created, the fake_dirent->reclen will be 0x1000. > it equals to the blocksize 4k, i.e. 0x1000. > > The problem seems to be related to the limitation of the 16-bit field > when the blocksize is set to 64k. > To address this, helpers like ext4_rec_len_{from,to}_disk has already > been introduced to complete the conversion between the encoded and the > plain form of rec_len. > > So fix this one by using the helper, and all the other in this file too. > > Cc: stable@kernel.org > Fixes: dbe89444042a ("ext4: Calculate and verify checksums for htree nodes") > Suggested-by: Andreas Dilger > Suggested-by: Darrick J. Wong > Signed-off-by: Shida Zhang > --- > v3->v4: > 1,Convert all the other rec_len, litrerally. > 2,Lift a helper output to a local variable. > --Suggested by Darrick. > v2->v3: > 1,Convert all the other rec_len if necessary, as suggested by Darrick. > 2,Rephrase the commit message. > v1->v2: > Use the existing helper to covert the rec_len, as suggested by Andreas. > > fs/ext4/namei.c | 26 +++++++++++++++----------- > 1 file changed, 15 insertions(+), 11 deletions(-) > > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > index 0caf6c730ce3..34fb2d1e66aa 100644 > --- a/fs/ext4/namei.c > +++ b/fs/ext4/namei.c > @@ -343,17 +343,17 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode, > struct buffer_head *bh) > { > struct ext4_dir_entry_tail *t; > + int blocksize = EXT4_BLOCK_SIZE(inode->i_sb); > > #ifdef PARANOID > struct ext4_dir_entry *d, *top; > > d = (struct ext4_dir_entry *)bh->b_data; > top = (struct ext4_dir_entry *)(bh->b_data + > - (EXT4_BLOCK_SIZE(inode->i_sb) - > - sizeof(struct ext4_dir_entry_tail))); > - while (d < top && d->rec_len) > + (blocksize - sizeof(struct ext4_dir_entry_tail))); > + while (d < top && ext4_rec_len_from_disk(d->rec_len, blocksize)) > d = (struct ext4_dir_entry *)(((void *)d) + > - le16_to_cpu(d->rec_len)); > + ext4_rec_len_from_disk(d->rec_len, blocksize)); > > if (d != top) > return NULL; > @@ -364,7 +364,8 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode, > #endif > > if (t->det_reserved_zero1 || > - le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) || > + (ext4_rec_len_from_disk(t->det_rec_len, blocksize) != > + sizeof(struct ext4_dir_entry_tail)) || > t->det_reserved_zero2 || > t->det_reserved_ft != EXT4_FT_DIR_CSUM) > return NULL; > @@ -445,13 +446,14 @@ static struct dx_countlimit *get_dx_countlimit(struct inode *inode, > struct ext4_dir_entry *dp; > struct dx_root_info *root; > int count_offset; > + int blocksize = EXT4_BLOCK_SIZE(inode->i_sb); > + unsigned int rlen = ext4_rec_len_from_disk(dirent->rec_len, blocksize); Nit: I'd have called ^^^^ this rec_len, not rlen, but I'll let Ted decide if he wants to change that on commit. Looks good! Reviewed-by: Darrick J. Wong --D > > - if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb)) > + if (rlen == blocksize) > count_offset = 8; > - else if (le16_to_cpu(dirent->rec_len) == 12) { > + else if (rlen == 12) { > dp = (struct ext4_dir_entry *)(((void *)dirent) + 12); > - if (le16_to_cpu(dp->rec_len) != > - EXT4_BLOCK_SIZE(inode->i_sb) - 12) > + if (ext4_rec_len_from_disk(dp->rec_len, blocksize) != blocksize - 12) > return NULL; > root = (struct dx_root_info *)(((void *)dp + 12)); > if (root->reserved_zero || > @@ -1315,6 +1317,7 @@ static int dx_make_map(struct inode *dir, struct buffer_head *bh, > unsigned int buflen = bh->b_size; > char *base = bh->b_data; > struct dx_hash_info h = *hinfo; > + int blocksize = EXT4_BLOCK_SIZE(dir->i_sb); > > if (ext4_has_metadata_csum(dir->i_sb)) > buflen -= sizeof(struct ext4_dir_entry_tail); > @@ -1335,11 +1338,12 @@ static int dx_make_map(struct inode *dir, struct buffer_head *bh, > map_tail--; > map_tail->hash = h.hash; > map_tail->offs = ((char *) de - base)>>2; > - map_tail->size = le16_to_cpu(de->rec_len); > + map_tail->size = ext4_rec_len_from_disk(de->rec_len, > + blocksize); > count++; > cond_resched(); > } > - de = ext4_next_entry(de, dir->i_sb->s_blocksize); > + de = ext4_next_entry(de, blocksize); > } > return count; > } > -- > 2.27.0 >