From patchwork Mon Mar 12 15:19:35 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 146150 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 3C4A3B6FA8 for ; Tue, 13 Mar 2012 03:19:54 +1100 (EST) Received: from localhost ([::1]:59010 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7704-00027a-OB for incoming@patchwork.ozlabs.org; Mon, 12 Mar 2012 11:17:28 -0400 Received: from eggs.gnu.org ([208.118.235.92]:39213) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S76za-0001Cg-A3 for qemu-devel@nongnu.org; Mon, 12 Mar 2012 11:17:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S76z6-0005O4-R2 for qemu-devel@nongnu.org; Mon, 12 Mar 2012 11:16:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46041) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S76z6-0005Nj-J7 for qemu-devel@nongnu.org; Mon, 12 Mar 2012 11:16:28 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q2CFGN4N007265 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 12 Mar 2012 11:16:26 -0400 Received: from dhcp-5-188.str.redhat.com (dhcp-5-175.str.redhat.com [10.32.5.175]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q2CFGHB2029582; Mon, 12 Mar 2012 11:16:22 -0400 From: Kevin Wolf To: anthony@codemonkey.ws Date: Mon, 12 Mar 2012 16:19:35 +0100 Message-Id: <1331565591-8414-5-git-send-email-kwolf@redhat.com> In-Reply-To: <1331565591-8414-1-git-send-email-kwolf@redhat.com> References: <1331565591-8414-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 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, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH 04/20] block: handle -EBUSY in bdrv_commit_all() 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 From: Stefan Hajnoczi Monitor operations that manipulate image files must not execute while a background job (like image streaming) is in progress. This prevents corruptions from happening when two pieces of code are manipulating the image file without knowledge of each other. The monitor "commit" command raises QERR_DEVICE_IN_USE when bdrv_commit() returns -EBUSY but "commit all" has no error handling. This is easy to fix, although note that we do not deliver a detailed error about which device was busy in the "commit all" case. Suggested-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block.c | 8 ++++++-- block.h | 2 +- blockdev.c | 9 ++++++--- 3 files changed, 13 insertions(+), 6 deletions(-) diff --git a/block.c b/block.c index 52ffe14..b88ee90 100644 --- a/block.c +++ b/block.c @@ -1244,13 +1244,17 @@ ro_cleanup: return ret; } -void bdrv_commit_all(void) +int bdrv_commit_all(void) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, list) { - bdrv_commit(bs); + int ret = bdrv_commit(bs); + if (ret < 0) { + return ret; + } } + return 0; } struct BdrvTrackedRequest { diff --git a/block.h b/block.h index 48d0bf3..415bb17 100644 --- a/block.h +++ b/block.h @@ -165,7 +165,7 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs); void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr); void bdrv_guess_geometry(BlockDriverState *bs, int *pcyls, int *pheads, int *psecs); int bdrv_commit(BlockDriverState *bs); -void bdrv_commit_all(void); +int bdrv_commit_all(void); int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file, const char *backing_fmt); void bdrv_register(BlockDriver *bdrv); diff --git a/blockdev.c b/blockdev.c index 96a893b..0e8666a 100644 --- a/blockdev.c +++ b/blockdev.c @@ -627,12 +627,15 @@ void do_commit(Monitor *mon, const QDict *qdict) { const char *device = qdict_get_str(qdict, "device"); BlockDriverState *bs; + int ret; if (!strcmp(device, "all")) { - bdrv_commit_all(); + ret = bdrv_commit_all(); + if (ret == -EBUSY) { + qerror_report(QERR_DEVICE_IN_USE, device); + return; + } } else { - int ret; - bs = bdrv_find(device); if (!bs) { qerror_report(QERR_DEVICE_NOT_FOUND, device);