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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 46BBBECAAA1 for ; Thu, 27 Oct 2022 18:34:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oo7g9-0001NA-7j; Thu, 27 Oct 2022 14:32:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oo7g6-0001Iq-9Y for qemu-devel@nongnu.org; Thu, 27 Oct 2022 14:32:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oo7g2-0002PS-Vi for qemu-devel@nongnu.org; Thu, 27 Oct 2022 14:32:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666895545; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YTxmdF/UnCq0KhrR2mBACaUPeFcUxBEWt7nmkQ85UmE=; b=OBZSoW/WYz9xmcPbV62WyDs+VJmZxxBYiZk4PAseCCzI2cAAaKXjsjtBFoMMvFKpsTupTV WerX09B/kx5W3crN4vTjEkurgxRZt0rH35uWSa88rZU1tsFQIsOm/vdivP/h8IOkhTfbXh hxhCs6D0BkuULRGNHI5FF7hxA3a1aQ8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-468-Jnd-Y3QfMPW8P3fxXm-7yQ-1; Thu, 27 Oct 2022 14:32:21 -0400 X-MC-Unique: Jnd-Y3QfMPW8P3fxXm-7yQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C1B8A1C07554; Thu, 27 Oct 2022 18:32:05 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id C98261121320; Thu, 27 Oct 2022 18:32:01 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org Subject: [PULL 04/58] vvfat: allow some writes to bootsector Date: Thu, 27 Oct 2022 20:30:52 +0200 Message-Id: <20221027183146.463129-5-kwolf@redhat.com> In-Reply-To: <20221027183146.463129-1-kwolf@redhat.com> References: <20221027183146.463129-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.515, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Hervé Poussineau 'reserved1' field in bootsector is used to mark volume dirty, or need to verify. Allow writes to bootsector which only changes the 'reserved1' field. This fixes I/O errors on Windows guests. Resolves: https://bugs.launchpad.net/qemu/+bug/1889421 Signed-off-by: Hervé Poussineau Message-Id: <20221010175511.3414357-2-hpoussin@reactos.org> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/vvfat.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/block/vvfat.c b/block/vvfat.c index f9bf8406d3..e76b42dbaf 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -2993,11 +2993,35 @@ DLOG(checkpoint()); vvfat_close_current_file(s); + if (sector_num == s->offset_to_bootsector && nb_sectors == 1) { + /* + * Write on bootsector. Allow only changing the reserved1 field, + * used to mark volume dirtiness + */ + unsigned char *bootsector = s->first_sectors + + s->offset_to_bootsector * 0x200; + /* + * LATER TODO: if FAT32, this is wrong (see init_directories(), + * which always creates a FAT16 bootsector) + */ + const int reserved1_offset = offsetof(bootsector_t, u.fat16.reserved1); + + for (i = 0; i < 0x200; i++) { + if (i != reserved1_offset && bootsector[i] != buf[i]) { + fprintf(stderr, "Tried to write to protected bootsector\n"); + return -1; + } + } + + /* Update bootsector with the only updatable byte, and return success */ + bootsector[reserved1_offset] = buf[reserved1_offset]; + return 0; + } + /* * Some sanity checks: * - do not allow writing to the boot sector */ - if (sector_num < s->offset_to_fat) return -1; -- 2.37.3