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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D1C2C433F5 for ; Tue, 5 Oct 2021 15:12:05 +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 99ECF6115A for ; Tue, 5 Oct 2021 15:12:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 99ECF6115A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:40182 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXm6t-0004RX-JO for qemu-devel@archiver.kernel.org; Tue, 05 Oct 2021 11:12:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53668) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXlXm-0003zO-OT for qemu-devel@nongnu.org; Tue, 05 Oct 2021 10:35:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46692) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXlXg-0005JE-IS for qemu-devel@nongnu.org; Tue, 05 Oct 2021 10:35:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633444539; 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=EX7rNbP1MyC8FFtaO9nErlvWtoIvqDmen8TdFpWCnzI=; b=I/i2PYPPc6mlG4mPRt1PMcXzu0hLG76YkEiVil4POoZKRULyAYcW8FkmEN33XJKzeRDMLk 5d7dM+/GoNgcJZqL0itHSeZOxvGjQd+Wr6ZdQ4jiUz8X7kaDi4pUR+a+EJOykuUQHJSQzb JCB+3OaPJmCOvf/4phg82opHz6a0VlY= 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-546-cBgngXWhPf-7hie4zLVRRg-1; Tue, 05 Oct 2021 10:35:36 -0400 X-MC-Unique: cBgngXWhPf-7hie4zLVRRg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CBE7184A5EC; Tue, 5 Oct 2021 14:35:35 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9AF411045E94; Tue, 5 Oct 2021 14:35:34 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [RFC PATCH v2 15/25] include/block/snapshot: global state API + assertions Date: Tue, 5 Oct 2021 10:32:05 -0400 Message-Id: <20211005143215.29500-16-eesposit@redhat.com> In-Reply-To: <20211005143215.29500-1-eesposit@redhat.com> References: <20211005143215.29500-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: Kevin Wolf , Fam Zheng , Vladimir Sementsov-Ogievskiy , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , Juan Quintela , qemu-devel@nongnu.org, John Snow , Emanuele Giuseppe Esposito , Richard Henderson , Markus Armbruster , "Dr. David Alan Gilbert" , Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Snapshots run also under the BQL lock, so they all are in the global state API. The aiocontext lock that they hold is currently an overkill and in future could be removed. Signed-off-by: Emanuele Giuseppe Esposito --- block/snapshot.c | 28 ++++++++++++++++++++++++++++ include/block/snapshot.h | 21 +++++++++++++++++++++ migration/savevm.c | 2 ++ 3 files changed, 51 insertions(+) diff --git a/block/snapshot.c b/block/snapshot.c index ccacda8bd5..e8756f7f90 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -57,6 +57,8 @@ int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info, QEMUSnapshotInfo *sn_tab, *sn; int nb_sns, i, ret; + g_assert(qemu_in_main_thread()); + ret = -ENOENT; nb_sns = bdrv_snapshot_list(bs, &sn_tab); if (nb_sns < 0) { @@ -105,6 +107,7 @@ bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs, bool ret = false; assert(id || name); + g_assert(qemu_in_main_thread()); nb_sns = bdrv_snapshot_list(bs, &sn_tab); if (nb_sns < 0) { @@ -200,6 +203,7 @@ static BlockDriverState *bdrv_snapshot_fallback(BlockDriverState *bs) int bdrv_can_snapshot(BlockDriverState *bs) { BlockDriver *drv = bs->drv; + g_assert(qemu_in_main_thread()); if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { return 0; } @@ -220,6 +224,9 @@ int bdrv_snapshot_create(BlockDriverState *bs, { BlockDriver *drv = bs->drv; BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs); + + g_assert(qemu_in_main_thread()); + if (!drv) { return -ENOMEDIUM; } @@ -240,6 +247,8 @@ int bdrv_snapshot_goto(BlockDriverState *bs, BdrvChild **fallback_ptr; int ret, open_ret; + g_assert(qemu_in_main_thread()); + if (!drv) { error_setg(errp, "Block driver is closed"); return -ENOMEDIUM; @@ -348,6 +357,8 @@ int bdrv_snapshot_delete(BlockDriverState *bs, BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs); int ret; + g_assert(qemu_in_main_thread()); + if (!drv) { error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs)); return -ENOMEDIUM; @@ -380,6 +391,8 @@ int bdrv_snapshot_list(BlockDriverState *bs, { BlockDriver *drv = bs->drv; BlockDriverState *fallback_bs = bdrv_snapshot_fallback(bs); + + g_assert(qemu_in_main_thread()); if (!drv) { return -ENOMEDIUM; } @@ -419,6 +432,8 @@ int bdrv_snapshot_load_tmp(BlockDriverState *bs, { BlockDriver *drv = bs->drv; + g_assert(qemu_in_main_thread()); + if (!drv) { error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs)); return -ENOMEDIUM; @@ -447,6 +462,8 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs, int ret; Error *local_err = NULL; + g_assert(qemu_in_main_thread()); + ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err); if (ret == -ENOENT || ret == -EINVAL) { error_free(local_err); @@ -515,6 +532,8 @@ bool bdrv_all_can_snapshot(bool has_devices, strList *devices, g_autoptr(GList) bdrvs = NULL; GList *iterbdrvs; + g_assert(qemu_in_main_thread()); + if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) { return false; } @@ -549,6 +568,8 @@ int bdrv_all_delete_snapshot(const char *name, g_autoptr(GList) bdrvs = NULL; GList *iterbdrvs; + g_assert(qemu_in_main_thread()); + if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) { return -1; } @@ -588,6 +609,8 @@ int bdrv_all_goto_snapshot(const char *name, g_autoptr(GList) bdrvs = NULL; GList *iterbdrvs; + g_assert(qemu_in_main_thread()); + if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) { return -1; } @@ -622,6 +645,8 @@ int bdrv_all_has_snapshot(const char *name, g_autoptr(GList) bdrvs = NULL; GList *iterbdrvs; + g_assert(qemu_in_main_thread()); + if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) { return -1; } @@ -663,6 +688,7 @@ int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn, { g_autoptr(GList) bdrvs = NULL; GList *iterbdrvs; + g_assert(qemu_in_main_thread()); if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) { return -1; @@ -703,6 +729,8 @@ BlockDriverState *bdrv_all_find_vmstate_bs(const char *vmstate_bs, g_autoptr(GList) bdrvs = NULL; GList *iterbdrvs; + g_assert(qemu_in_main_thread()); + if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) { return NULL; } diff --git a/include/block/snapshot.h b/include/block/snapshot.h index 940345692f..3a84849388 100644 --- a/include/block/snapshot.h +++ b/include/block/snapshot.h @@ -45,6 +45,27 @@ typedef struct QEMUSnapshotInfo { uint64_t icount; /* record/replay step */ } QEMUSnapshotInfo; +/* + * Global state (GS) API. These functions run under the BQL lock. + * + * If a function modifies the graph, it also uses drain and/or + * aio_context_acquire/release to be sure it has unique access. + * aio_context locking is needed together with BQL because of + * the thread-safe I/O API that concurrently runs and accesses + * the graph without the BQL. + * + * It is important to note that not all of these functions are + * necessarily limited to running under the BQL, but they would + * require additional auditing and may small thread-safety changes + * to move them into the I/O API. Often it's not worth doing that + * work since the APIs are only used with the BQL held at the + * moment, so they have been placed in the GS API (for now). + * + * All functions in this header must use this assertion: + * g_assert(qemu_in_main_thread()); + * to catch when they are accidentally called without the BQL. + */ + int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info, const char *name); bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs, diff --git a/migration/savevm.c b/migration/savevm.c index 7b7b64bd13..439f736ad5 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2785,6 +2785,8 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate, g_autoptr(GDateTime) now = g_date_time_new_now_local(); AioContext *aio_context; + g_assert(qemu_in_main_thread()); + if (migration_is_blocked(errp)) { return false; } -- 2.27.0