From patchwork Fri Jul 5 20:16:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Snow X-Patchwork-Id: 1128251 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 ozlabs.org (Postfix) with ESMTPS id 45gRMw2Hg7z9sNf for ; Sat, 6 Jul 2019 06:31:56 +1000 (AEST) Received: from localhost ([::1]:55900 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hjUs6-0004i2-8J for incoming@patchwork.ozlabs.org; Fri, 05 Jul 2019 16:31:54 -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) 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+incoming=patchwork.ozlabs.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(BdrvDirtyBitmap *bitmap, return hbitmap_next_dirty_area(bitmap->bitmap, offset, bytes); } +/** + * 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 BdrvDirtyBitmap *src, HBitmap **backup, Error **errp) { @@ -833,6 +839,38 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src, goto out; } + ret = bdrv_dirty_bitmap_merge_internal(dest, src, backup, false); + assert(ret); + +out: + qemu_mutex_unlock(dest->mutex); + if (src->mutex != 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 != dest->mutex) { + qemu_mutex_lock(src->mutex); + } + } + if (backup) { *backup = dest->bitmap; dest->bitmap = hbitmap_alloc(dest->size, hbitmap_granularity(*backup)); @@ -840,11 +878,13 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src, } else { ret = hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap); } - assert(ret); -out: - qemu_mutex_unlock(dest->mutex); - if (src->mutex != dest->mutex) { - qemu_mutex_unlock(src->mutex); + if (lock) { + qemu_mutex_unlock(dest->mutex); + if (src->mutex != 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 offset, int64_t bytes); 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); void bdrv_inc_in_flight(BlockDriverState *bs); void bdrv_dec_in_flight(BlockDriverState *bs);