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 X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2CAC1C433B4 for ; Thu, 29 Apr 2021 09:07:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4ED261449 for ; Thu, 29 Apr 2021 09:07:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232734AbhD2JHz (ORCPT ); Thu, 29 Apr 2021 05:07:55 -0400 Received: from mx2.suse.de ([195.135.220.15]:41374 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240062AbhD2JHy (ORCPT ); Thu, 29 Apr 2021 05:07:54 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1619687227; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cQ2ngzZaVaRwNLM06AwozGCjJj+HKkzIZX1xPnT9UBg=; b=MfMnqYcc5sEhpNIBmcDTicJgbi3mr7Xds+7waZTeWwxRIbGywh04eV47+oKnc9fffS7Ofx TGULoWz9D5Y8MAD8WBBA88zBEO+JeedKDZMawAAo9tGh1EoJcXGn/ihYNUMXMIA9QhAklv AFlFQbscUIkW6r6bM5YOso8ru8GTjn4= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 736FEAE58; Thu, 29 Apr 2021 09:07:07 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: Nikolay Borisov , Su Yue Subject: [PATCH v2 2/3] btrfs-progs: image: enlarge the output file if no tree modification is needed for restore Date: Thu, 29 Apr 2021 17:06:57 +0800 Message-Id: <20210429090658.245238-3-wqu@suse.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210429090658.245238-1-wqu@suse.com> References: <20210429090658.245238-1-wqu@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org [BUG] If restoring dumpped image into a new file, under most cases kernel will reject it: # mkfs.btrfs -f /dev/test/test # btrfs-image /dev/test/test /tmp/dump # btrfs-image -r /tmp/dump ~/test.img # mount ~/test.img /mnt/btrfs mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error. # dmesg -t | tail -n 7 loop0: detected capacity change from 10592 to 0 BTRFS info (device loop0): disk space caching is enabled BTRFS info (device loop0): has skinny extents BTRFS info (device loop0): flagging fs with big metadata feature BTRFS error (device loop0): device total_bytes should be at most 5423104 but found 10737418240 BTRFS error (device loop0): failed to read chunk tree: -22 BTRFS error (device loop0): open_ctree failed [CAUSE] When btrfs-image restores an image into a file, and the source image contains only single device, then we don't need to modify the chunk/device tree, as we can reuse the existing chunk/dev tree without any problem. This also means, for such restore, we also won't do any target file enlarge. This behavior itself is fine, as at that time, kernel won't check if the device is smaller than the device size recorded in device tree. But later kernel commit 3a160a933111 ("btrfs: drop never met disk total bytes check in verify_one_dev_extent") introduces new check on device size at mount time, rejecting any loop file which is smaller than the original device size. [FIX] Do extra file enlarge for single device restore if the restored file is smaller than the device size. Reported-by: Nikolay Borisov Signed-off-by: Qu Wenruo Reviewed-by: Su Yue --- image/main.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/image/main.c b/image/main.c index 24393188e5e3..188f387b3354 100644 --- a/image/main.c +++ b/image/main.c @@ -2706,6 +2706,49 @@ static int restore_metadump(const char *input, FILE *out, int old_restore, close_ctree(info->chunk_root); if (ret) goto out; + } else { + struct btrfs_root *root; + struct stat st; + u64 dev_size; + + if (!info) { + root = open_ctree_fd(fileno(out), target, 0, 0); + if (!root) { + error("open ctree failed in %s", target); + ret = -EIO; + goto out; + } + + info = root->fs_info; + + dev_size = btrfs_stack_device_total_bytes( + &info->super_copy->dev_item); + close_ctree(root); + info = NULL; + } else { + dev_size = btrfs_stack_device_total_bytes( + &info->super_copy->dev_item); + } + + /* + * We don't need extra tree modification, but if the output is + * a file, we need to enlarge the output file so that + * newer kernel won't report error. + */ + ret = fstat(fileno(out), &st); + if (ret < 0) { + error("failed to stat result image: %m"); + ret = -errno; + goto out; + } + if (S_ISREG(st.st_mode) && st.st_size < dev_size) { + ret = ftruncate64(fileno(out), dev_size); + if (ret < 0) { + error("failed to enlarge result image: %m"); + ret = -errno; + goto out; + } + } } out: mdrestore_destroy(&mdrestore, num_threads); -- 2.31.1