From patchwork Thu Sep 20 19:13:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Cody X-Patchwork-Id: 185466 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 4A10F2C0078 for ; Fri, 21 Sep 2012 05:55:41 +1000 (EST) Received: from localhost ([::1]:39905 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEmD1-0001FJ-2i for incoming@patchwork.ozlabs.org; Thu, 20 Sep 2012 15:14:47 -0400 Received: from eggs.gnu.org ([208.118.235.92]:41140) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEmCF-0007h6-6p for qemu-devel@nongnu.org; Thu, 20 Sep 2012 15:14:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TEmCD-0000S0-PJ for qemu-devel@nongnu.org; Thu, 20 Sep 2012 15:13:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44562) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEmCD-0000Rs-G8 for qemu-devel@nongnu.org; Thu, 20 Sep 2012 15:13:57 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q8KJDgI2020704 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 20 Sep 2012 15:13:42 -0400 Received: from localhost (ovpn-112-41.phx2.redhat.com [10.3.112.41]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q8KJDdeJ007161 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Thu, 20 Sep 2012 15:13:41 -0400 From: Jeff Cody To: qemu-devel@nongnu.org Date: Thu, 20 Sep 2012 15:13:17 -0400 Message-Id: In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, pbonzini@redhat.com, eblake@redhat.com, supriyak@linux.vnet.ibm.com Subject: [Qemu-devel] [PATCH v4 01/19] block: correctly set the keep_read_only flag X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org I believe the bs->keep_read_only flag is supposed to reflect the initial open state of the device. If the device is initially opened R/O, then commit operations, or reopen operations changing to R/W, are prohibited. Currently, the keep_read_only flag is only accurate for the active layer, and its backing file. Subsequent images end up always having the keep_read_only flag set. For instance, what happens now: [ base ] kro = 1, ro = 1 | v [ snap-1 ] kro = 1, ro = 1 | v [ snap-2 ] kro = 0, ro = 1 | v [ active ] kro = 0, ro = 0 What we want: [ base ] kro = 0, ro = 1 | v [ snap-1 ] kro = 0, ro = 1 | v [ snap-2 ] kro = 0, ro = 1 | v [ active ] kro = 0, ro = 0 Signed-off-by: Jeff Cody --- block.c | 14 +++++++------- block.h | 1 + 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/block.c b/block.c index e78039b..4c0e7f5 100644 --- a/block.c +++ b/block.c @@ -668,7 +668,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename, open_flags |= BDRV_O_RDWR; } - bs->keep_read_only = bs->read_only = !(open_flags & BDRV_O_RDWR); + bs->read_only = !(open_flags & BDRV_O_RDWR); /* Open the image, either directly or using a protocol */ if (drv->bdrv_file_open) { @@ -808,6 +808,12 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, goto unlink_and_fail; } + if (flags & BDRV_O_RDWR) { + flags |= BDRV_O_ALLOW_RDWR; + } + + bs->keep_read_only = !(flags & BDRV_O_ALLOW_RDWR); + /* Open the image */ ret = bdrv_open_common(bs, filename, flags, drv); if (ret < 0) { @@ -837,12 +843,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, bdrv_close(bs); return ret; } - if (bs->is_temporary) { - bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR); - } else { - /* base image inherits from "parent" */ - bs->backing_hd->keep_read_only = bs->keep_read_only; - } } if (!bdrv_key_required(bs)) { diff --git a/block.h b/block.h index 2e2be11..4d919c2 100644 --- a/block.h +++ b/block.h @@ -80,6 +80,7 @@ typedef struct BlockDevOps { #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */ #define BDRV_O_INCOMING 0x0800 /* consistency hint for incoming migration */ #define BDRV_O_CHECK 0x1000 /* open solely for consistency check */ +#define BDRV_O_ALLOW_RDWR 0x2000 /* allow reopen to change from r/o to r/w */ #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)