From nobody Sun Apr 13 04:32:25 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1488315503626365.05153937925525; Tue, 28 Feb 2017 12:58:23 -0800 (PST) Received: from localhost ([::1]:36870 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cioqk-0006pz-D9 for importer@patchew.org; Tue, 28 Feb 2017 15:58:22 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45554) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cioX6-0006XD-Jl for qemu-devel@nongnu.org; Tue, 28 Feb 2017 15:38:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cioX5-00083h-Ag for qemu-devel@nongnu.org; Tue, 28 Feb 2017 15:38:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44416) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cioX1-00081f-0Q; Tue, 28 Feb 2017 15:37:59 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 282A58047B; Tue, 28 Feb 2017 20:37:59 +0000 (UTC) Received: from noname.redhat.com (ovpn-116-177.ams2.redhat.com [10.36.116.177]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1SKapFa021888; Tue, 28 Feb 2017 15:37:57 -0500 From: Kevin Wolf To: qemu-block@nongnu.org Date: Tue, 28 Feb 2017 21:36:34 +0100 Message-Id: <1488314205-16264-36-git-send-email-kwolf@redhat.com> In-Reply-To: <1488314205-16264-1-git-send-email-kwolf@redhat.com> References: <1488314205-16264-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 28 Feb 2017 20:37:59 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 35/46] stream: Use real permissions in streaming block job X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The correct permissions are relatively obvious here (and explained in code comments). For intermediate streaming, we need to reopen the top node read-write before creating the job now because the permissions system catches attempts to get the BLK_PERM_WRITE_UNCHANGED permission on a read-only node. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Acked-by: Fam Zheng --- block/stream.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/block/stream.c b/block/stream.c index ba8650f..b9c2f43 100644 --- a/block/stream.c +++ b/block/stream.c @@ -84,6 +84,8 @@ static void stream_complete(BlockJob *job, void *opaque) =20 /* Reopen the image back in read-only mode if necessary */ if (s->bs_flags !=3D bdrv_get_flags(bs)) { + /* Give up write permissions before making it read-only */ + blk_set_perm(job->blk, 0, BLK_PERM_ALL, &error_abort); bdrv_reopen(bs, s->bs_flags, NULL); } =20 @@ -229,28 +231,35 @@ void stream_start(const char *job_id, BlockDriverStat= e *bs, BlockDriverState *iter; int orig_bs_flags; =20 - /* FIXME Use real permissions */ - s =3D block_job_create(job_id, &stream_job_driver, bs, 0, BLK_PERM_ALL, - speed, BLOCK_JOB_DEFAULT, NULL, NULL, errp); - if (!s) { - return; - } - /* Make sure that the image is opened in read-write mode */ orig_bs_flags =3D bdrv_get_flags(bs); if (!(orig_bs_flags & BDRV_O_RDWR)) { if (bdrv_reopen(bs, orig_bs_flags | BDRV_O_RDWR, errp) !=3D 0) { - block_job_unref(&s->common); return; } } =20 - /* Block all intermediate nodes between bs and base, because they - * will disappear from the chain after this operation */ + /* Prevent concurrent jobs trying to modify the graph structure here, = we + * already have our own plans. Also don't allow resize as the image si= ze is + * queried only at the job start and then cached. */ + s =3D block_job_create(job_id, &stream_job_driver, bs, + BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANG= ED | + BLK_PERM_GRAPH_MOD, + BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANG= ED | + BLK_PERM_WRITE, + speed, BLOCK_JOB_DEFAULT, NULL, NULL, errp); + if (!s) { + goto fail; + } + + /* Block all intermediate nodes between bs and base, because they will + * disappear from the chain after this operation. The streaming job re= ads + * every block only once, assuming that it doesn't change, so block wr= ites + * and resizes. */ for (iter =3D backing_bs(bs); iter && iter !=3D base; iter =3D backing= _bs(iter)) { - /* FIXME Use real permissions */ block_job_add_bdrv(&s->common, "intermediate node", iter, 0, - BLK_PERM_ALL, &error_abort); + BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHA= NGED, + &error_abort); } =20 s->base =3D base; @@ -260,4 +269,10 @@ void stream_start(const char *job_id, BlockDriverState= *bs, s->on_error =3D on_error; trace_stream_start(bs, base, s); block_job_start(&s->common); + return; + +fail: + if (orig_bs_flags !=3D bdrv_get_flags(bs)) { + bdrv_reopen(bs, s->bs_flags, NULL); + } } --=20 1.8.3.1