From patchwork Wed Jun 21 12:50:25 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 9801749 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 331CC6086C for ; Wed, 21 Jun 2017 12:55:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 22D65285B1 for ; Wed, 21 Jun 2017 12:55:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 17B88285C8; Wed, 21 Jun 2017 12:55:06 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 946AD285B1 for ; Wed, 21 Jun 2017 12:55:05 +0000 (UTC) Received: from localhost ([::1]:53749 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNfA0-00024h-Lt for patchwork-qemu-devel@patchwork.kernel.org; Wed, 21 Jun 2017 08:55:04 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33790) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNf6E-0007cl-Lp for qemu-devel@nongnu.org; Wed, 21 Jun 2017 08:51:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNf6D-0004td-GL for qemu-devel@nongnu.org; Wed, 21 Jun 2017 08:51:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55518) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dNf67-0004le-Cd; Wed, 21 Jun 2017 08:51:03 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4A70A7CE14; Wed, 21 Jun 2017 12:51:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 4A70A7CE14 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mreitz@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 4A70A7CE14 Received: from localhost (unknown [10.40.205.46]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E42AC18672; Wed, 21 Jun 2017 12:51:00 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 21 Jun 2017 14:50:25 +0200 Message-Id: <20170621125047.30294-4-mreitz@redhat.com> In-Reply-To: <20170621125047.30294-1-mreitz@redhat.com> References: <20170621125047.30294-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 21 Jun 2017 12:51:02 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v5 03/25] block: Add BDS.backing_overridden X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Alberto Garcia , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP If the backing file is overridden, this most probably does change the guest-visible data of a BDS. Therefore, we will need to consider this in bdrv_refresh_filename(). Adding a new field to the BDS is not nice, but it is very simple and exactly keeps track of whether the backing file has been overridden. This commit adds a FIXME which will be remedied by a follow-up commit. Until then, the respective piece of code will not result in any behavior that is worse than what we currently have. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- include/block/block_int.h | 1 + block.c | 13 +++++++++++++ block/mirror.c | 4 ++++ blockdev.c | 16 ++++++++++++++++ 4 files changed, 34 insertions(+) diff --git a/include/block/block_int.h b/include/block/block_int.h index 6820027..bedf19b 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -547,6 +547,7 @@ struct BlockDriverState { char backing_file[PATH_MAX]; /* if non zero, the image is a diff of this file image */ char backing_format[16]; /* if non-zero and backing_file exists */ + bool backing_overridden; /* backing file has been specified by the user */ QDict *full_open_options; char exact_filename[PATH_MAX]; diff --git a/block.c b/block.c index 2926f53..2addec0 100644 --- a/block.c +++ b/block.c @@ -2147,6 +2147,11 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, reference = qdict_get_try_str(parent_options, bdref_key); if (reference || qdict_haskey(options, "file.filename")) { backing_filename[0] = '\0'; + + /* FIXME: Should also be set to true if @options contains other runtime + * options which control the data that is read from the backing + * BDS */ + bs->backing_overridden = true; } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { QDECREF(options); goto free_exit; @@ -2346,6 +2351,9 @@ static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, goto out; } + bs_snapshot->backing_overridden = true; + bdrv_refresh_filename(bs_snapshot); + out: QDECREF(snapshot_options); g_free(tmp_filename); @@ -2476,6 +2484,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, backing = qdict_get_try_str(options, "backing"); if (backing && *backing == '\0') { flags |= BDRV_O_NO_BACKING; + bs->backing_overridden = true; qdict_del(options, "backing"); } @@ -4799,6 +4808,10 @@ void bdrv_refresh_filename(BlockDriverState *bs) * refresh those first */ QLIST_FOREACH(child, &bs->children, next) { bdrv_refresh_filename(child->bs); + + if (child->role == &child_backing && child->bs->backing_overridden) { + bs->backing_overridden = true; + } } if (drv->bdrv_refresh_filename) { diff --git a/block/mirror.c b/block/mirror.c index df6c8bb..6ac3956 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -536,6 +536,10 @@ static void mirror_exit(BlockJob *job, void *opaque) error_report_err(local_err); data->ret = -EPERM; } + + /* The target image's file already has been created with the backing + * file we just set, so there is no need to set backing_overridden or + * call bdrv_refresh_filename(). */ } if (s->to_replace) { diff --git a/blockdev.c b/blockdev.c index 6472548..c15308a 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1787,6 +1787,8 @@ static void external_snapshot_commit(BlkActionState *common) { ExternalSnapshotState *state = DO_UPCAST(ExternalSnapshotState, common, common); + TransactionAction *action = common->action; + bool image_was_existing = false; /* We don't need (or want) to use the transactional * bdrv_reopen_multiple() across all the entries at once, because we @@ -1795,6 +1797,20 @@ static void external_snapshot_commit(BlkActionState *common) bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR, NULL); } + + if (action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC) { + BlockdevSnapshotSync *s = action->u.blockdev_snapshot_sync.data; + if (s->has_mode && s->mode == NEW_IMAGE_MODE_EXISTING) { + image_was_existing = true; + } + } else { + image_was_existing = true; + } + + if (image_was_existing) { + state->new_bs->backing_overridden = true; + bdrv_refresh_filename(state->new_bs); + } } static void external_snapshot_abort(BlkActionState *common)