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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8322BC00454 for ; Mon, 9 Dec 2019 16:07:00 +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 4D67020692 for ; Mon, 9 Dec 2019 16:07:00 +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="TbS67out" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D67020692 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]:42022 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ieLYp-0002Xr-Ec for qemu-devel@archiver.kernel.org; Mon, 09 Dec 2019 11:06:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59011) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ieLY5-0001rJ-3u for qemu-devel@nongnu.org; Mon, 09 Dec 2019 11:06:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ieLY2-00089O-5H for qemu-devel@nongnu.org; Mon, 09 Dec 2019 11:06:11 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:56463 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ieLY1-00088b-JN for qemu-devel@nongnu.org; Mon, 09 Dec 2019 11:06:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575907568; 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=+RbFC4eEhTNJHx837P7drSLdPkMBBSzO7Ars7IuAwP0=; b=TbS67outPcWbvXxndLiLluu/L4D+5jip+gaMdZDerC2U+HocJ+AkGraW53D5etkBZRhj0r 9g/nIi5r/18+8QACFl1q7UokQPpeTOcMFBWIURIHl8C1DSNS04ZDf71EWeUea3uL0LQSvj vxtPTnuPQNIBqxW8vo5439CUsx5nU3Q= 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-249-K4Pr2tYPPv2KII3Mft9F_Q-1; Mon, 09 Dec 2019 11:06:07 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0B8A4107ACC5; Mon, 9 Dec 2019 16:06:06 +0000 (UTC) Received: from linux.fritz.box (ovpn-117-116.ams2.redhat.com [10.36.117.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DE5A646; Mon, 9 Dec 2019 16:06:02 +0000 (UTC) Date: Mon, 9 Dec 2019 17:06:01 +0100 From: Kevin Wolf To: Sergio Lopez Subject: Re: [PATCH v5 4/4] blockdev: honor bdrv_try_set_aio_context() context requirements Message-ID: <20191209160601.GB6715@linux.fritz.box> References: <20191128104129.250206-1-slp@redhat.com> <20191128104129.250206-5-slp@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191128104129.250206-5-slp@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: K4Pr2tYPPv2KII3Mft9F_Q-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: Max Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org, Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 28.11.2019 um 11:41 hat Sergio Lopez geschrieben: > bdrv_try_set_aio_context() requires that the old context is held, and > the new context is not held. Fix all the occurrences where it's not > done this way. >=20 > Suggested-by: Max Reitz > Signed-off-by: Sergio Lopez > --- > blockdev.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 62 insertions(+), 10 deletions(-) >=20 > diff --git a/blockdev.c b/blockdev.c > index 152a0f7454..e33abd7fd2 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -1535,6 +1535,7 @@ static void external_snapshot_prepare(BlkActionStat= e *common, > DO_UPCAST(ExternalSnapshotState, common, co= mmon); > TransactionAction *action =3D common->action; > AioContext *aio_context; > + AioContext *old_context; > int ret; > =20 > /* 'blockdev-snapshot' and 'blockdev-snapshot-sync' have similar > @@ -1675,7 +1676,16 @@ static void external_snapshot_prepare(BlkActionSta= te *common, > goto out; > } > =20 > + /* Honor bdrv_try_set_aio_context() context acquisition requirements= . */ > + old_context =3D bdrv_get_aio_context(state->new_bs); > + aio_context_release(aio_context); > + aio_context_acquire(old_context); > + > ret =3D bdrv_try_set_aio_context(state->new_bs, aio_context, errp); > + > + aio_context_release(old_context); > + aio_context_acquire(aio_context); > + > if (ret < 0) { > goto out; > } > @@ -1775,11 +1785,13 @@ static void drive_backup_prepare(BlkActionState *= common, Error **errp) > BlockDriverState *target_bs; > BlockDriverState *source =3D NULL; > AioContext *aio_context; > + AioContext *old_context; > QDict *options; > Error *local_err =3D NULL; > int flags; > int64_t size; > bool set_backing_hd =3D false; > + int ret; > =20 > assert(common->action->type =3D=3D TRANSACTION_ACTION_KIND_DRIVE_BAC= KUP); > backup =3D common->action->u.drive_backup.data; > @@ -1868,6 +1880,20 @@ static void drive_backup_prepare(BlkActionState *c= ommon, Error **errp) > goto out; > } > =20 > + /* Honor bdrv_try_set_aio_context() context acquisition requirements= . */ > + old_context =3D bdrv_get_aio_context(target_bs); > + aio_context_release(aio_context); > + aio_context_acquire(old_context); > + > + ret =3D bdrv_try_set_aio_context(target_bs, aio_context, errp); > + aio_context_release(old_context); > + aio_context_acquire(aio_context); > + > + if (ret < 0) { > + goto out; I think this needs to be 'goto unref'. Or in fact, I think you need to hold the AioContext of a bs to bdrv_unref() it, so maybe 'goto out' is right, but you need to unref target_bs while you still hold old_context. > + } > + > if (set_backing_hd) { > bdrv_set_backing_hd(target_bs, source, &local_err); > if (local_err) { > @@ -1947,6 +1973,8 @@ static void blockdev_backup_prepare(BlkActionState = *common, Error **errp) > BlockDriverState *bs; > BlockDriverState *target_bs; > AioContext *aio_context; > + AioContext *old_context; > + int ret; > =20 > assert(common->action->type =3D=3D TRANSACTION_ACTION_KIND_BLOCKDEV_= BACKUP); > backup =3D common->action->u.blockdev_backup.data; > @@ -1961,7 +1989,18 @@ static void blockdev_backup_prepare(BlkActionState= *common, Error **errp) > return; > } > =20 > + /* Honor bdrv_try_set_aio_context() context acquisition requirements= . */ > aio_context =3D bdrv_get_aio_context(bs); > + old_context =3D bdrv_get_aio_context(target_bs); > + aio_context_acquire(old_context); > + > + ret =3D bdrv_try_set_aio_context(target_bs, aio_context, errp); > + if (ret < 0) { > + aio_context_release(old_context); > + return; > + } > + > + aio_context_release(old_context); > aio_context_acquire(aio_context); > state->bs =3D bs; > =20 > @@ -3562,7 +3601,6 @@ static BlockJob *do_backup_common(BackupCommon *bac= kup, > BlockJob *job =3D NULL; > BdrvDirtyBitmap *bmap =3D NULL; > int job_flags =3D JOB_DEFAULT; > - int ret; > =20 > if (!backup->has_speed) { > backup->speed =3D 0; > @@ -3586,11 +3624,6 @@ static BlockJob *do_backup_common(BackupCommon *ba= ckup, > backup->compress =3D false; > } > =20 > - ret =3D bdrv_try_set_aio_context(target_bs, aio_context, errp); > - if (ret < 0) { > - return NULL; > - } > - > if ((backup->sync =3D=3D MIRROR_SYNC_MODE_BITMAP) || > (backup->sync =3D=3D MIRROR_SYNC_MODE_INCREMENTAL)) { > /* done before desugaring 'incremental' to print the right messa= ge */ > @@ -3825,6 +3858,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **err= p) > BlockDriverState *bs; > BlockDriverState *source, *target_bs; > AioContext *aio_context; > + AioContext *old_context; > BlockMirrorBackingMode backing_mode; > Error *local_err =3D NULL; > QDict *options =3D NULL; > @@ -3937,10 +3971,19 @@ void qmp_drive_mirror(DriveMirror *arg, Error **e= rrp) > (arg->mode =3D=3D NEW_IMAGE_MODE_EXISTING || > !bdrv_has_zero_init(target_bs))); > =20 > + > + /* Honor bdrv_try_set_aio_context() context acquisition requirements= . */ > + old_context =3D bdrv_get_aio_context(target_bs); > + aio_context_release(aio_context); > + aio_context_acquire(old_context); > + > ret =3D bdrv_try_set_aio_context(target_bs, aio_context, errp); > + > + aio_context_release(old_context); > + aio_context_acquire(aio_context); > + > if (ret < 0) { > - bdrv_unref(target_bs); > - goto out; > + goto unref; > } Here you don't forget to unref target_bs, but it has still the same problem as above that you need to hold old_context during bdrv_unref(). Kevin