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 08978C433F5 for ; Mon, 14 Mar 2022 11:38:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239266AbiCNLjz (ORCPT ); Mon, 14 Mar 2022 07:39:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239351AbiCNLiu (ORCPT ); Mon, 14 Mar 2022 07:38:50 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEF6B4338A; Mon, 14 Mar 2022 04:37:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 326C9B80DBA; Mon, 14 Mar 2022 11:37:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 914C5C36AE5; Mon, 14 Mar 2022 11:37:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647257857; bh=M8ax33quUGmZY4WEvx5nH5KNIApyPzylG8aYXe9hmrg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y998LP5GI/lo79FmHKOfP+Bg+E5aoEzgIE883yxdh3V7q6D2PcHEBaltPCe1Jao7X +KKMNLc7tRNIZLdFHk1gCNFqstdvWgSZDlPCPKr6NCZGINqkZc5//Nvo4f4j3Gs+K/ H6VsfaT0PUTjGjhMEPZt3fL46hFnKMbN2Fw+uleA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Triplett , Theodore Tso Subject: [PATCH 4.14 22/23] ext4: add check to prevent attempting to resize an fs with sparse_super2 Date: Mon, 14 Mar 2022 12:34:35 +0100 Message-Id: <20220314112731.699764053@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220314112731.050583127@linuxfoundation.org> References: <20220314112731.050583127@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josh Triplett commit b1489186cc8391e0c1e342f9fbc3eedf6b944c61 upstream. The in-kernel ext4 resize code doesn't support filesystem with the sparse_super2 feature. It fails with errors like this and doesn't finish the resize: EXT4-fs (loop0): resizing filesystem from 16640 to 7864320 blocks EXT4-fs warning (device loop0): verify_reserved_gdb:760: reserved GDT 2 missing grp 1 (32770) EXT4-fs warning (device loop0): ext4_resize_fs:2111: error (-22) occurred during file system resize EXT4-fs (loop0): resized filesystem to 2097152 To reproduce: mkfs.ext4 -b 4096 -I 256 -J size=32 -E resize=$((256*1024*1024)) -O sparse_super2 ext4.img 65M truncate -s 30G ext4.img mount ext4.img /mnt python3 -c 'import fcntl, os, struct ; fd = os.open("/mnt", os.O_RDONLY | os.O_DIRECTORY) ; fcntl.ioctl(fd, 0x40086610, struct.pack("Q", 30 * 1024 * 1024 * 1024 // 4096), False) ; os.close(fd)' dmesg | tail e2fsck ext4.img The userspace resize2fs tool has a check for this case: it checks if the filesystem has sparse_super2 set and if the kernel provides /sys/fs/ext4/features/sparse_super2. However, the former check requires manually reading and parsing the filesystem superblock. Detect this case in ext4_resize_begin and error out early with a clear error message. Signed-off-by: Josh Triplett Link: https://lore.kernel.org/r/74b8ae78405270211943cd7393e65586c5faeed1.1623093259.git.josh@joshtriplett.org Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/resize.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -74,6 +74,11 @@ int ext4_resize_begin(struct super_block return -EPERM; } + if (ext4_has_feature_sparse_super2(sb)) { + ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2"); + return -EOPNOTSUPP; + } + if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags)) ret = -EBUSY;