{"id":818224,"url":"http://patchwork.ozlabs.org/api/patches/818224/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170925122808.14561-2-kwolf@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170925122808.14561-2-kwolf@redhat.com>","list_archive_url":null,"date":"2017-09-25T12:28:04","name":"[1/5] block: Introduce BdrvChildRole.update_filename","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"d9b1f95db9e48459c64bcec866a7039e29009da7","submitter":{"id":2714,"url":"http://patchwork.ozlabs.org/api/people/2714/?format=json","name":"Kevin Wolf","email":"kwolf@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170925122808.14561-2-kwolf@redhat.com/mbox/","series":[{"id":4949,"url":"http://patchwork.ozlabs.org/api/series/4949/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4949","date":"2017-09-25T12:28:05","name":"commit: Support multiple roots above top node","version":1,"mbox":"http://patchwork.ozlabs.org/series/4949/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/818224/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/818224/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","ext-mx09.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx09.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=kwolf@redhat.com"],"Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3y13NS4TT2z9tXD\n\tfor ;\n\tMon, 25 Sep 2017 22:31:20 +1000 (AEST)","from localhost ([::1]:42271 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dwSXe-0005jI-NB\n\tfor incoming@patchwork.ozlabs.org; Mon, 25 Sep 2017 08:31:18 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:47218)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dwSUn-0003VG-KQ\n\tfor qemu-devel@nongnu.org; Mon, 25 Sep 2017 08:28:22 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dwSUm-000655-Iv\n\tfor qemu-devel@nongnu.org; Mon, 25 Sep 2017 08:28:21 -0400","from mx1.redhat.com ([209.132.183.28]:59094)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from )\n\tid 1dwSUg-00061q-MX; Mon, 25 Sep 2017 08:28:14 -0400","from smtp.corp.redhat.com\n\t(int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id B938B4ACA4;\n\tMon, 25 Sep 2017 12:28:13 +0000 (UTC)","from localhost.localdomain.com (ovpn-116-119.ams2.redhat.com\n\t[10.36.116.119])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id 7D7E960E3E;\n\tMon, 25 Sep 2017 12:28:12 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com B938B4ACA4","From":"Kevin Wolf ","To":"qemu-block@nongnu.org","Date":"Mon, 25 Sep 2017 14:28:04 +0200","Message-Id":"<20170925122808.14561-2-kwolf@redhat.com>","In-Reply-To":"<20170925122808.14561-1-kwolf@redhat.com>","References":"<20170925122808.14561-1-kwolf@redhat.com>","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.12","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.38]);\n\tMon, 25 Sep 2017 12:28:13 +0000 (UTC)","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]","X-Received-From":"209.132.183.28","Subject":"[Qemu-devel] [PATCH 1/5] block: Introduce\n\tBdrvChildRole.update_filename","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"kwolf@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"},"content":"There is no good reason for bdrv_drop_intermediate() to know the active\nlayer above the subchain it is operating on - even more so, because\nthe assumption that there is a single active layer above it is not\ngenerally true.\n\nIn order to prepare removal of the active parameter, use a BdrvChildRole\ncallback to update the backing file string in the overlay image instead\nof directly calling bdrv_change_backing_file().\n\nSigned-off-by: Kevin Wolf \n---\n include/block/block_int.h | 6 ++++++\n block.c | 33 ++++++++++++++++++++++++++++-----\n 2 files changed, 34 insertions(+), 5 deletions(-)","diff":"diff --git a/include/block/block_int.h b/include/block/block_int.h\nindex 99abe2ce74..e6d53cc15e 100644\n--- a/include/block/block_int.h\n+++ b/include/block/block_int.h\n@@ -544,6 +544,12 @@ struct BdrvChildRole {\n \n void (*attach)(BdrvChild *child);\n void (*detach)(BdrvChild *child);\n+\n+ /* Notifies the parent that the filename of its child has changed (e.g.\n+ * because the direct child was removed from the backing chain), so that it\n+ * can update its reference. */\n+ int (*update_filename)(BdrvChild *child, BlockDriverState *new_base,\n+ const char *filename, Error **errp);\n };\n \n extern const BdrvChildRole child_file;\ndiff --git a/block.c b/block.c\nindex 5c65fac672..7ac8cd521b 100644\n--- a/block.c\n+++ b/block.c\n@@ -981,6 +981,21 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options,\n *child_flags = flags;\n }\n \n+static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,\n+ const char *filename, Error **errp)\n+{\n+ BlockDriverState *parent = c->opaque;\n+ int ret;\n+\n+ ret = bdrv_change_backing_file(parent, filename,\n+ base->drv ? base->drv->format_name : \"\");\n+ if (ret < 0) {\n+ error_setg_errno(errp, ret, \"Could not update backing file link\");\n+ }\n+\n+ return ret;\n+}\n+\n const BdrvChildRole child_backing = {\n .get_parent_desc = bdrv_child_get_parent_desc,\n .attach = bdrv_backing_attach,\n@@ -989,6 +1004,7 @@ const BdrvChildRole child_backing = {\n .drained_begin = bdrv_child_cb_drained_begin,\n .drained_end = bdrv_child_cb_drained_end,\n .inactivate = bdrv_child_cb_inactivate,\n+ .update_filename = bdrv_backing_update_filename,\n };\n \n static int bdrv_open_flags(BlockDriverState *bs, int flags)\n@@ -3470,6 +3486,8 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,\n Error *local_err = NULL;\n int ret = -EIO;\n \n+ bdrv_ref(top);\n+\n if (!top->drv || !base->drv) {\n goto exit;\n }\n@@ -3494,11 +3512,15 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,\n }\n \n /* success - we can delete the intermediate states, and link top->base */\n- backing_file_str = backing_file_str ? backing_file_str : base->filename;\n- ret = bdrv_change_backing_file(new_top_bs, backing_file_str,\n- base->drv ? base->drv->format_name : \"\");\n- if (ret) {\n- goto exit;\n+ if (new_top_bs->backing->role->update_filename) {\n+ backing_file_str = backing_file_str ? backing_file_str : base->filename;\n+ ret = new_top_bs->backing->role->update_filename(new_top_bs->backing,\n+ base, backing_file_str,\n+ &local_err);\n+ if (ret < 0) {\n+ bdrv_set_backing_hd(new_top_bs, top, &error_abort);\n+ goto exit;\n+ }\n }\n \n bdrv_set_backing_hd(new_top_bs, base, &local_err);\n@@ -3510,6 +3532,7 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,\n \n ret = 0;\n exit:\n+ bdrv_unref(top);\n return ret;\n }\n \n","prefixes":["1/5"]}