From patchwork Thu Aug 30 18:47:07 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Cody X-Patchwork-Id: 180854 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 7F0752C0118 for ; Fri, 31 Aug 2012 04:47:44 +1000 (EST) Received: from localhost ([::1]:39609 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T79mI-00044B-Hb for incoming@patchwork.ozlabs.org; Thu, 30 Aug 2012 14:47:42 -0400 Received: from eggs.gnu.org ([208.118.235.92]:40114) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T79m1-0003sw-6r for qemu-devel@nongnu.org; Thu, 30 Aug 2012 14:47:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T79m0-0005Fg-2Z for qemu-devel@nongnu.org; Thu, 30 Aug 2012 14:47:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50189) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T79lz-0005Fb-R1 for qemu-devel@nongnu.org; Thu, 30 Aug 2012 14:47:24 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q7UIlJRf014589 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 30 Aug 2012 14:47:19 -0400 Received: from localhost (ovpn-112-23.phx2.redhat.com [10.3.112.23]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id q7UIlGL7016775 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Thu, 30 Aug 2012 14:47:18 -0400 From: Jeff Cody To: qemu-devel@nongnu.org Date: Thu, 30 Aug 2012 14:47:07 -0400 Message-Id: <431ff7f85fb9c83b5300360273322e6a0c76aee2.1346352124.git.jcody@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 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, stefanha@gmail.com, eblake@redhat.com, supriyak@linux.vnet.ibm.com Subject: [Qemu-devel] [PATCH 1/7] 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 | 16 +++++++--------- block.h | 1 + 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/block.c b/block.c index 470bdcc..e31b76f 100644 --- a/block.c +++ b/block.c @@ -655,7 +655,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename, * Clear flags that are internal to the block layer before opening the * image. */ - open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); + open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_ALLOW_RDWR); /* * Snapshots should be writable. @@ -664,8 +664,6 @@ 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); - /* Open the image, either directly or using a protocol */ if (drv->bdrv_file_open) { ret = drv->bdrv_file_open(bs, filename, open_flags); @@ -804,6 +802,12 @@ 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) { @@ -833,12 +837,6 @@ 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)