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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 9DF44C282DE for ; Thu, 13 Mar 2025 10:45:15 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tsg3Q-0004gV-L7; Thu, 13 Mar 2025 06:44:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tsg3N-0004g9-Ug for qemu-devel@nongnu.org; Thu, 13 Mar 2025 06:44:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tsg3L-0005GT-4s for qemu-devel@nongnu.org; Thu, 13 Mar 2025 06:44:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741862677; 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: in-reply-to:in-reply-to:references:references; bh=rJ+haAW2INS4114alcfsTqPuq+CzNL5oF99gQLZlCzU=; b=DiQ/dR7GK4jna2bhJV4hqHa0tsovaT43MkQTooLqcMod6Ih6GR5ul9xCd6zl33lN4Tlyhx yChVL40+nL63QmlqOeoHCUGY09MlSO4KcZrQJank7HjY/LrJdzXgsJiGnNgq6wWo6AVbnd 7bTKV7EH5KriJ3XHLT54CXknMv13FSg= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-119-1DgwbsnSM-ar1ASKVP26Pg-1; Thu, 13 Mar 2025 06:44:36 -0400 X-MC-Unique: 1DgwbsnSM-ar1ASKVP26Pg-1 X-Mimecast-MFC-AGG-ID: 1DgwbsnSM-ar1ASKVP26Pg_1741862675 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8C6651801A1A; Thu, 13 Mar 2025 10:44:35 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.22.74.4]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4DBAD1828A87; Thu, 13 Mar 2025 10:44:34 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 9179421E66C4; Thu, 13 Mar 2025 11:44:30 +0100 (CET) From: Markus Armbruster To: Kevin Wolf Cc: Markus Armbruster , qemu-devel@nongnu.org, qemu-block@nongnu.org, hreitz@redhat.com, vsementsov@yandex-team.ru Subject: Re: [PATCH] block: Fix bdrv_activate() not to fail without medium In-Reply-To: (Kevin Wolf's message of "Thu, 13 Mar 2025 11:17:23 +0100") References: <20250312143758.1660177-1-armbru@redhat.com> Date: Thu, 13 Mar 2025 11:44:30 +0100 Message-ID: <87ldt99pm9.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Kevin Wolf writes: > Am 12.03.2025 um 15:37 hat Markus Armbruster geschrieben: >> bdrv_activate() returns failure without setting an error when >> !bs->drv. This is suspicious. Turns out it used to succeed then, >> until commit 5416645fcf82 changed it to return -ENOMEDIUM. >> >> Return zero instead. >> >> Fixes: 5416645fcf82 (block: return error-code from bdrv_invalidate_cache) >> Signed-off-by: Markus Armbruster > > The commit message sounds more theoretical. Did you find this only by > code inspection? Do we know what the effect on real-world cases is, so > we could add a sentence about it to the commit message? Maybe we could > even have a qemu-iotests case to show the effect? > > I absolutely agree that returning -ENOMEDIUM while not setting errp is > wrong. But without an example of what is affected, it's not obvious to > me which part of it needs to be fixed. Code inspection. Here's my somewhat extended rationale for my fix. The code of interest used to be in bdrv_invalidate_cache(). Have a look at commit 5a8a30db477: commit 5a8a30db4771675480829d7d3bf35a138e9c35f1 Author: Kevin Wolf Date: Wed Mar 12 15:59:16 2014 +0100 block: Add error handling to bdrv_invalidate_cache() If it returns an error, the migrated VM will not be started, but qemu exits with an error message. Signed-off-by: Kevin Wolf Reviewed-by: Juan Quintela Reviewed-by: Eric Blake Reviewed-by: Benoit Canet [...] diff --git a/include/block/block.h b/include/block/block.h index bd34d14109..1ed55d839a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -329,8 +329,8 @@ BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, BlockDriverCompletionFunc *cb, void *opaque); /* Invalidate any cached metadata used by image formats */ -void bdrv_invalidate_cache(BlockDriverState *bs); -void bdrv_invalidate_cache_all(void); +void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp); +void bdrv_invalidate_cache_all(Error **errp); void bdrv_clear_incoming_migration_all(void); diff --git a/include/block/block_int.h b/include/block/block_int.h index 4fc5ea8a65..cd5bc7308a 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -153,7 +153,7 @@ struct BlockDriver { /* * Invalidate any cached meta-data. */ - void (*bdrv_invalidate_cache)(BlockDriverState *bs); + void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp); /* * Flushes all data that was already written to the OS all the way down to diff --git a/block.c b/block.c index 53f5b44fbb..acb70fde3d 100644 --- a/block.c +++ b/block.c @@ -4781,27 +4781,43 @@ flush_parent: return bdrv_co_flush(bs->file); } -void bdrv_invalidate_cache(BlockDriverState *bs) +void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) { + Error *local_err = NULL; + int ret; + if (!bs->drv) { return; } if (bs->drv->bdrv_invalidate_cache) { - bs->drv->bdrv_invalidate_cache(bs); + bs->drv->bdrv_invalidate_cache(bs, &local_err); } else if (bs->file) { - bdrv_invalidate_cache(bs->file); + bdrv_invalidate_cache(bs->file, &local_err); + } + if (local_err) { + error_propagate(errp, local_err); + return; } - refresh_total_sectors(bs, bs->total_sectors); + ret = refresh_total_sectors(bs, bs->total_sectors); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not refresh total sector count"); + return; + } } -void bdrv_invalidate_cache_all(void) +void bdrv_invalidate_cache_all(Error **errp) { BlockDriverState *bs; + Error *local_err = NULL; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { - bdrv_invalidate_cache(bs); + bdrv_invalidate_cache(bs, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } } }