From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BC1DC46499 for ; Fri, 5 Jul 2019 20:33:47 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 15F5321670 for ; Fri, 5 Jul 2019 20:33:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 15F5321670 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55924 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hjUtu-0006p1-Bo for qemu-devel@archiver.kernel.org; Fri, 05 Jul 2019 16:33:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60999) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hjUdu-0005Pz-Pi for qemu-devel@nongnu.org; Fri, 05 Jul 2019 16:17:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hjUds-000739-OH for qemu-devel@nongnu.org; Fri, 05 Jul 2019 16:17:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60816) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hjUdn-0006wD-6P; Fri, 05 Jul 2019 16:17:07 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7693159464; Fri, 5 Jul 2019 20:17:06 +0000 (UTC) Received: from probe.redhat.com (ovpn-122-149.rdu2.redhat.com [10.10.122.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9348286432; Fri, 5 Jul 2019 20:17:04 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Fri, 5 Jul 2019 16:16:22 -0400 Message-Id: <20190705201631.26266-10-jsnow@redhat.com> In-Reply-To: <20190705201631.26266-1-jsnow@redhat.com> References: <20190705201631.26266-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 05 Jul 2019 20:17:06 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 09/18] block/dirty-bitmap: add bdrv_dirty_bitmap_merge_internal X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , Kevin Wolf , vsementsov@virtuozzo.com, Juan Quintela , Wen Congyang , Xie Changlong , "Dr. David Alan Gilbert" , Markus Armbruster , John Snow , Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" I'm surprised it didn't come up sooner, but sometimes we have a +busy bitmap as a source. This is dangerous from the QMP API, but if we are the owner that marked the bitmap busy, it's safe to merge it using it as a read only source. It is not safe in the general case to allow users to read from in-use bitmaps, so create an internal variant that foregoes the safety checking. Signed-off-by: John Snow --- block/dirty-bitmap.c | 50 +++++++++++++++++++++++++++++++++++---- include/block/block_int.h | 3 +++ 2 files changed, 48 insertions(+), 5 deletions(-) diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index 95a9c2a5d8..c5b66ae9ed 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -810,6 +810,12 @@ bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitm= ap *bitmap, return hbitmap_next_dirty_area(bitmap->bitmap, offset, bytes); } =20 +/** + * bdrv_merge_dirty_bitmap: merge src into dest. + * Ensures permissions on bitmaps are reasonable; use for public API. + * + * @backup: If provided, make a copy of dest here prior to merge. + */ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitma= p *src, HBitmap **backup, Error **errp) { @@ -833,6 +839,38 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, = const BdrvDirtyBitmap *src, goto out; } =20 + ret =3D bdrv_dirty_bitmap_merge_internal(dest, src, backup, false); + assert(ret); + +out: + qemu_mutex_unlock(dest->mutex); + if (src->mutex !=3D dest->mutex) { + qemu_mutex_unlock(src->mutex); + } +} + +/** + * bdrv_dirty_bitmap_merge_internal: merge src into dest. + * Does NOT check bitmap permissions; not suitable for use as public API= . + * + * @backup: If provided, make a copy of dest here prior to merge. + * @lock: If true, lock and unlock bitmaps on the way in/out. + * returns true if the merge succeeded; false if unattempted. + */ +bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest, + const BdrvDirtyBitmap *src, + HBitmap **backup, + bool lock) +{ + bool ret; + + if (lock) { + qemu_mutex_lock(dest->mutex); + if (src->mutex !=3D dest->mutex) { + qemu_mutex_lock(src->mutex); + } + } + if (backup) { *backup =3D dest->bitmap; dest->bitmap =3D hbitmap_alloc(dest->size, hbitmap_granularity(*= backup)); @@ -840,11 +878,13 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest,= const BdrvDirtyBitmap *src, } else { ret =3D hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap); } - assert(ret); =20 -out: - qemu_mutex_unlock(dest->mutex); - if (src->mutex !=3D dest->mutex) { - qemu_mutex_unlock(src->mutex); + if (lock) { + qemu_mutex_unlock(dest->mutex); + if (src->mutex !=3D dest->mutex) { + qemu_mutex_unlock(src->mutex); + } } + + return ret; } diff --git a/include/block/block_int.h b/include/block/block_int.h index e1f2aa627e..83ffdf4950 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -1238,6 +1238,9 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t o= ffset, int64_t bytes); =20 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup)= ; +bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest, + const BdrvDirtyBitmap *src, + HBitmap **backup, bool lock); =20 void bdrv_inc_in_flight(BlockDriverState *bs); void bdrv_dec_in_flight(BlockDriverState *bs); --=20 2.21.0