From patchwork Wed May 13 09:50:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Shinkevich X-Patchwork-Id: 1289143 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) 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=virtuozzo.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 49MVVj2zhyz9sT3 for ; Wed, 13 May 2020 19:58:36 +1000 (AEST) Received: from localhost ([::1]:41290 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jYo9p-0003Io-5t for incoming@patchwork.ozlabs.org; Wed, 13 May 2020 05:58:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44716) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jYo30-0006j4-5x; Wed, 13 May 2020 05:51:30 -0400 Received: from relay.sw.ru ([185.231.240.75]:54018) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jYo2z-0003ZG-2l; Wed, 13 May 2020 05:51:29 -0400 Received: from dhcp-172-16-25-136.sw.ru ([172.16.25.136] helo=localhost.sw.ru) by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1jYo2W-0001e4-8J; Wed, 13 May 2020 12:51:00 +0300 From: Andrey Shinkevich To: qemu-block@nongnu.org Subject: [PATCH v5 12/15] copy-on-read: add filter append/drop functions Date: Wed, 13 May 2020 12:50:53 +0300 Message-Id: <1589363456-1035571-13-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1589363456-1035571-1-git-send-email-andrey.shinkevich@virtuozzo.com> References: <1589363456-1035571-1-git-send-email-andrey.shinkevich@virtuozzo.com> Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.shinkevich@virtuozzo.com; helo=relay.sw.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/13 05:51:06 X-ACL-Warn: Detected OS = Linux 3.1-3.10 X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: kwolf@redhat.com, fam@euphon.net, vsementsov@virtuozzo.com, armbru@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, andrey.shinkevich@virtuozzo.com, den@openvz.org, mreitz@redhat.com, jsnow@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Provide API for the COR-filter insertion/removal. Also, drop the filter child permissions for an inactive state when the filter node is being removed. Signed-off-by: Andrey Shinkevich --- block/copy-on-read.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++ block/copy-on-read.h | 36 ++++++++++++++++++ 2 files changed, 138 insertions(+) create mode 100644 block/copy-on-read.h diff --git a/block/copy-on-read.c b/block/copy-on-read.c index 4030d56..229a97c 100644 --- a/block/copy-on-read.c +++ b/block/copy-on-read.c @@ -24,11 +24,20 @@ #include "qemu/cutils.h" #include "block/block_int.h" #include "qemu/module.h" +#include "qapi/error.h" +#include "qapi/qmp/qdict.h" +#include "block/copy-on-read.h" +typedef struct BDRVStateCOR { + bool active; +} BDRVStateCOR; + static int cor_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { + BDRVStateCOR *state = bs->opaque; + bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false, errp); if (!bs->file) { @@ -42,6 +51,8 @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags, ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & bs->file->bs->supported_zero_flags); + state->active = true; + return 0; } @@ -57,6 +68,17 @@ static void cor_child_perm(BlockDriverState *bs, BdrvChild *c, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { + BDRVStateCOR *s = bs->opaque; + + if (!s->active) { + /* + * While the filter is being removed + */ + *nperm = 0; + *nshared = BLK_PERM_ALL; + return; + } + *nperm = perm & PERM_PASSTHROUGH; *nshared = (shared & PERM_PASSTHROUGH) | PERM_UNCHANGED; @@ -150,6 +172,7 @@ static int cor_change_backing_file(BlockDriverState *bs, static BlockDriver bdrv_copy_on_read = { .format_name = "copy-on-read", + .instance_size = sizeof(BDRVStateCOR), .bdrv_open = cor_open, .bdrv_child_perm = cor_child_perm, @@ -178,4 +201,83 @@ static void bdrv_copy_on_read_init(void) bdrv_register(&bdrv_copy_on_read); } + +static BlockDriverState *create_filter_node(BlockDriverState *bs, + const char *filter_node_name, + Error **errp) +{ + QDict *opts = qdict_new(); + + qdict_put_str(opts, "driver", "copy-on-read"); + qdict_put_str(opts, "file", bdrv_get_node_name(bs)); + if (filter_node_name) { + qdict_put_str(opts, "node-name", filter_node_name); + } + + return bdrv_open(NULL, NULL, opts, BDRV_O_RDWR, errp); +} + + +BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs, + const char *filter_node_name, + Error **errp) +{ + BlockDriverState *cor_filter_bs; + BDRVStateCOR *state; + Error *local_err = NULL; + + cor_filter_bs = create_filter_node(bs, filter_node_name, errp); + if (cor_filter_bs == NULL) { + error_prepend(errp, "Could not create filter node: "); + return NULL; + } + + if (!filter_node_name) { + cor_filter_bs->implicit = true; + } + + bdrv_drained_begin(bs); + bdrv_replace_node(bs, cor_filter_bs, &local_err); + bdrv_drained_end(bs); + + if (local_err) { + bdrv_unref(cor_filter_bs); + error_propagate(errp, local_err); + return NULL; + } + + state = cor_filter_bs->opaque; + state->active = true; + + return cor_filter_bs; +} + + +void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs) +{ + BdrvChild *child; + BlockDriverState *bs; + BDRVStateCOR *s = cor_filter_bs->opaque; + + child = bdrv_filtered_rw_child(cor_filter_bs); + if (!child) { + return; + } + bs = child->bs; + + /* Retain the BDS until we complete the graph change. */ + bdrv_ref(bs); + /* Hold a guest back from writing while permissions are being reset. */ + bdrv_drained_begin(bs); + /* Drop permissions before the graph change. */ + s->active = false; + bdrv_child_refresh_perms(cor_filter_bs, child, &error_abort); + bdrv_replace_node(cor_filter_bs, bs, &error_abort); + + bdrv_drained_end(bs); + bdrv_unref(bs); + bdrv_unref(cor_filter_bs); +} + + block_init(bdrv_copy_on_read_init); diff --git a/block/copy-on-read.h b/block/copy-on-read.h new file mode 100644 index 0000000..db03c6c --- /dev/null +++ b/block/copy-on-read.h @@ -0,0 +1,36 @@ +/* + * Copy-on-read filter block driver + * + * The filter driver performs Copy-On-Read (COR) operations + * + * Copyright (c) 2018-2020 Virtuozzo International GmbH. + * + * Author: + * Andrey Shinkevich + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#ifndef COPY_ON_READ_FILTER +#define COPY_ON_READ_FILTER + +#include "block/block_int.h" +#include "block/block-copy.h" + +BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs, + const char *filter_node_name, + Error **errp); +void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs); + +#endif /* COPY_ON_READ_FILTER */