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=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 48DD4C433E1 for ; Fri, 17 Jul 2020 10:57:53 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 12E1A20717 for ; Fri, 17 Jul 2020 10:57:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KPrcLxfk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 12E1A20717 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33538 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jwO3s-0006ow-Cj for qemu-devel@archiver.kernel.org; Fri, 17 Jul 2020 06:57:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44888) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwO0m-0001Kj-NT for qemu-devel@nongnu.org; Fri, 17 Jul 2020 06:54:40 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:51620 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jwO0k-0004RQ-Sb for qemu-devel@nongnu.org; Fri, 17 Jul 2020 06:54:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594983278; 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=WNBvx4THG0M9pR8FSX6Ps6fHmdrKHB/so8DozTyNlvw=; b=KPrcLxfkqsJlO7o5wyzQEX+9Exg87IpoYGHF3eArwNNOGuz3F5oL2OOo8KH1Qw6A/dclMe X9MS5uUHKCOY6DerufzYZ/6CwVFCoSbkzibWraLnQZ6O5+NmxcyZci/9c+7NAlG/rc1mUu Trg3DRmRQLjx/FPwSuFIzKpBKk4mb24= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-181-NLdMEcwnOCunYQJuxnjR3Q-1; Fri, 17 Jul 2020 06:54:36 -0400 X-MC-Unique: NLdMEcwnOCunYQJuxnjR3Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7ED5F100CCC1; Fri, 17 Jul 2020 10:54:35 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-113-80.ams2.redhat.com [10.36.113.80]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5C5246FED1; Fri, 17 Jul 2020 10:54:31 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH for-5.1 2/3] file-posix: Fix check_hdev_writable() with auto-read-only Date: Fri, 17 Jul 2020 12:54:25 +0200 Message-Id: <20200717105426.51134-3-kwolf@redhat.com> In-Reply-To: <20200717105426.51134-1-kwolf@redhat.com> References: <20200717105426.51134-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/17 05:27:47 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" For Linux block devices, being able to open the device read-write doesn't necessarily mean that the device is actually writable (one example is a read-only LV, as you get with lvchange -pr ). We have check_hdev_writable() to check this condition and fail opening the image read-write if it's not actually writable. However, this check doesn't take auto-read-only into account, but results in a hard failure instead of downgrading to read-only where possible. Fix this and do the writable check not based on BDRV_O_RDWR, but only when this actually results in opening the file read-write. A second check is inserted in raw_reconfigure_getfd() to have the same check when dynamic auto-read-only upgrades an image file from read-only to read-write. Signed-off-by: Kevin Wolf --- block/file-posix.c | 33 +++++++++++++++++++++------------ 1 file changed, 21 insertions(+), 12 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index e35e15185a..659f780570 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -401,7 +401,7 @@ static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp) } } -static int check_hdev_writable(BDRVRawState *s) +static int check_hdev_writable(int fd) { #if defined(BLKROGET) /* Linux block devices can be configured "read-only" using blockdev(8). @@ -415,7 +415,7 @@ static int check_hdev_writable(BDRVRawState *s) struct stat st; int readonly = 0; - if (fstat(s->fd, &st)) { + if (fstat(fd, &st)) { return -errno; } @@ -423,7 +423,7 @@ static int check_hdev_writable(BDRVRawState *s) return 0; } - if (ioctl(s->fd, BLKROGET, &readonly) < 0) { + if (ioctl(fd, BLKROGET, &readonly) < 0) { return -errno; } @@ -618,6 +618,15 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, } s->fd = fd; + /* Check s->open_flags rather than bdrv_flags due to auto-read-only */ + if (s->open_flags & O_RDWR) { + ret = check_hdev_writable(s->fd); + if (ret < 0) { + error_setg_errno(errp, -ret, "The device is not writable"); + goto fail; + } + } + s->perm = 0; s->shared_perm = BLK_PERM_ALL; @@ -1010,6 +1019,15 @@ static int raw_reconfigure_getfd(BlockDriverState *bs, int flags, } } + if (fd != -1 && (*open_flags & O_RDWR)) { + ret = check_hdev_writable(fd); + if (ret < 0) { + qemu_close(fd); + error_setg_errno(errp, -ret, "The device is not writable"); + return -1; + } + } + return fd; } @@ -3454,15 +3472,6 @@ hdev_open_Mac_error: /* Since this does ioctl the device must be already opened */ bs->sg = hdev_is_sg(bs); - if (flags & BDRV_O_RDWR) { - ret = check_hdev_writable(s); - if (ret < 0) { - raw_close(bs); - error_setg_errno(errp, -ret, "The device is not writable"); - return ret; - } - } - return ret; } -- 2.25.4