From patchwork Mon Sep 7 18:19:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 306008 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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, 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 848F6C43461 for ; Mon, 7 Sep 2020 18:27:09 +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 01DF820738 for ; Mon, 7 Sep 2020 18:27:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LXP5IUDT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01DF820738 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]:33844 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kFLr9-0000mB-Tz for qemu-devel@archiver.kernel.org; Mon, 07 Sep 2020 14:27:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42528) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kFLl9-0005N1-8w for qemu-devel@nongnu.org; Mon, 07 Sep 2020 14:20:55 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:27594 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kFLl0-0004Vu-GE for qemu-devel@nongnu.org; Mon, 07 Sep 2020 14:20:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599502845; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HbqVe6JGkNq+PJJ48CcAI3Q247uYJgPwb4VmaUhxqSY=; b=LXP5IUDTQxwhAMAY24+0sEQPv6U1J/q6MDTD+VXspo4n+Sd3YOr3mRWtR9dAp1gYWR6pNr DKck0QjImgMjhSEA7/CxB0g/tM+eoPpkJwSxwjwYng8NTYZ5NOV7SOxfNY3K/RRXxan0mk RxKqOV2O4kbCrZhNLSJjqiT6uHU5dn8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-296-KKaPejNnOmCxbkaoK12g5g-1; Mon, 07 Sep 2020 14:20:44 -0400 X-MC-Unique: KKaPejNnOmCxbkaoK12g5g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1B4F5807335; Mon, 7 Sep 2020 18:20:43 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-114-154.ams2.redhat.com [10.36.114.154]) by smtp.corp.redhat.com (Postfix) with ESMTP id 00D5160BF3; Mon, 7 Sep 2020 18:20:41 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH 13/29] block/export: Move refcount from NBDExport to BlockExport Date: Mon, 7 Sep 2020 20:19:55 +0200 Message-Id: <20200907182011.521007-14-kwolf@redhat.com> In-Reply-To: <20200907182011.521007-1-kwolf@redhat.com> References: <20200907182011.521007-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.61; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/07 03:05:01 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Having a refcount makes sense for all types of block exports. It is also a prerequisite for keeping a list of all exports at the BlockExport level. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- include/block/export.h | 15 +++++++++ include/block/nbd.h | 2 -- block/export/export.c | 14 ++++++++ blockdev-nbd.c | 2 +- nbd/server.c | 72 +++++++++++++++++++----------------------- 5 files changed, 63 insertions(+), 42 deletions(-) diff --git a/include/block/export.h b/include/block/export.h index e7af2c7687..5236a35e12 100644 --- a/include/block/export.h +++ b/include/block/export.h @@ -24,12 +24,27 @@ typedef struct BlockExportDriver { /* Creates and starts a new block export */ BlockExport *(*create)(BlockExportOptions *, Error **); + + /* + * Frees a removed block export. This function is only called after all + * references have been dropped. + */ + void (*delete)(BlockExport *); } BlockExportDriver; struct BlockExport { const BlockExportDriver *drv; + + /* + * Reference count for this block export. This includes strong references + * both from the owner (qemu-nbd or the monitor) and clients connected to + * the export. + */ + int refcount; }; BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp); +void blk_exp_ref(BlockExport *exp); +void blk_exp_unref(BlockExport *exp); #endif diff --git a/include/block/nbd.h b/include/block/nbd.h index 1dafe70615..e3bd112227 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -338,8 +338,6 @@ NBDExport *nbd_export_new(BlockDriverState *bs, void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk); void nbd_export_close(NBDExport *exp); void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp); -void nbd_export_get(NBDExport *exp); -void nbd_export_put(NBDExport *exp); AioContext *nbd_export_aio_context(NBDExport *exp); NBDExport *nbd_export_find(const char *name); diff --git a/block/export/export.c b/block/export/export.c index 05bc5e3744..baba4e94ff 100644 --- a/block/export/export.c +++ b/block/export/export.c @@ -49,6 +49,20 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) return drv->create(export, errp); } +void blk_exp_ref(BlockExport *exp) +{ + assert(exp->refcount > 0); + exp->refcount++; +} + +void blk_exp_unref(BlockExport *exp) +{ + assert(exp->refcount > 0); + if (--exp->refcount == 0) { + exp->drv->delete(exp); + } +} + void qmp_block_export_add(BlockExportOptions *export, Error **errp) { blk_exp_add(export, errp); diff --git a/blockdev-nbd.c b/blockdev-nbd.c index 7bb0b09697..e208324d42 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -236,7 +236,7 @@ BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp) /* The list of named exports has a strong reference to this export now and * our only way of accessing it is through nbd_export_find(), so we can drop * the strong reference that is @exp. */ - nbd_export_put(exp); + blk_exp_unref((BlockExport*) exp); out: aio_context_release(aio_context); diff --git a/nbd/server.c b/nbd/server.c index fb70374df5..7be81c7bda 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -83,7 +83,6 @@ struct NBDRequestData { struct NBDExport { BlockExport common; - int refcount; BlockBackend *blk; char *name; @@ -499,7 +498,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, } QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); - nbd_export_get(client->exp); + blk_exp_ref(&client->exp->common); nbd_check_meta_export(client); return 0; @@ -707,7 +706,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) client->exp = exp; client->check_align = check_align; QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); - nbd_export_get(client->exp); + blk_exp_ref(&client->exp->common); nbd_check_meta_export(client); rc = 1; } @@ -1406,7 +1405,7 @@ void nbd_client_put(NBDClient *client) g_free(client->tlsauthz); if (client->exp) { QTAILQ_REMOVE(&client->exp->clients, client, next); - nbd_export_put(client->exp); + blk_exp_unref(&client->exp->common); } g_free(client); } @@ -1538,7 +1537,8 @@ NBDExport *nbd_export_new(BlockDriverState *bs, exp = g_new0(NBDExport, 1); exp->common = (BlockExport) { - .drv = &blk_exp_nbd, + .drv = &blk_exp_nbd, + .refcount = 1, }; /* @@ -1567,7 +1567,6 @@ NBDExport *nbd_export_new(BlockDriverState *bs, blk_set_enable_write_cache(blk, !writethrough); blk_set_allow_aio_context_change(blk, true); - exp->refcount = 1; QTAILQ_INIT(&exp->clients); exp->blk = blk; exp->name = g_strdup(name); @@ -1626,8 +1625,9 @@ NBDExport *nbd_export_new(BlockDriverState *bs, exp->ctx = ctx; blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); + blk_exp_ref(&exp->common); QTAILQ_INSERT_TAIL(&exports, exp, next); - nbd_export_get(exp); + return exp; fail: @@ -1660,7 +1660,7 @@ void nbd_export_close(NBDExport *exp) { NBDClient *client, *next; - nbd_export_get(exp); + blk_exp_ref(&exp->common); /* * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a * close mode that stops advertising the export to new clients but @@ -1672,13 +1672,13 @@ void nbd_export_close(NBDExport *exp) client_close(client, true); } if (exp->name) { - nbd_export_put(exp); + blk_exp_unref(&exp->common); g_free(exp->name); exp->name = NULL; QTAILQ_REMOVE(&exports, exp, next); QTAILQ_INSERT_TAIL(&closed_exports, exp, next); } - nbd_export_put(exp); + blk_exp_unref(&exp->common); } void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) @@ -1695,47 +1695,41 @@ void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); } -void nbd_export_get(NBDExport *exp) -{ - assert(exp->refcount > 0); - exp->refcount++; -} - -void nbd_export_put(NBDExport *exp) +static void nbd_export_delete(BlockExport *blk_exp) { - assert(exp->refcount > 0); - if (--exp->refcount == 0) { - assert(exp->name == NULL); - assert(QTAILQ_EMPTY(&exp->clients)); + NBDExport *exp = container_of(blk_exp, NBDExport, common); - g_free(exp->description); - exp->description = NULL; + assert(exp->name == NULL); + assert(QTAILQ_EMPTY(&exp->clients)); - if (exp->blk) { - if (exp->eject_notifier_blk) { - notifier_remove(&exp->eject_notifier); - blk_unref(exp->eject_notifier_blk); - } - blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, - blk_aio_detach, exp); - blk_unref(exp->blk); - exp->blk = NULL; - } + g_free(exp->description); + exp->description = NULL; - if (exp->export_bitmap) { - bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); - g_free(exp->export_bitmap_context); + if (exp->blk) { + if (exp->eject_notifier_blk) { + notifier_remove(&exp->eject_notifier); + blk_unref(exp->eject_notifier_blk); } + blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, + blk_aio_detach, exp); + blk_unref(exp->blk); + exp->blk = NULL; + } - QTAILQ_REMOVE(&closed_exports, exp, next); - g_free(exp); - aio_wait_kick(); + if (exp->export_bitmap) { + bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); + g_free(exp->export_bitmap_context); } + + QTAILQ_REMOVE(&closed_exports, exp, next); + g_free(exp); + aio_wait_kick(); } const BlockExportDriver blk_exp_nbd = { .type = BLOCK_EXPORT_TYPE_NBD, .create = nbd_export_create, + .delete = nbd_export_delete, }; void nbd_export_close_all(void)