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 030DFC433EF for ; Fri, 4 Mar 2022 17:03:19 +0000 (UTC) Received: from localhost ([::1]:33220 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nQBKo-00054P-Le for qemu-devel@archiver.kernel.org; Fri, 04 Mar 2022 12:03:19 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51716) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nQB5r-0005JA-7g for qemu-devel@nongnu.org; Fri, 04 Mar 2022 11:47:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:56396) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nQB5l-0007P4-VZ for qemu-devel@nongnu.org; Fri, 04 Mar 2022 11:47:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646412465; 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=N3T3OAZawTd3+Cmmka1mE/tIuTurkvGvdz+HOStlLm8=; b=NAMQA3WFLdmEJVJYS+/th0FXWxNXYlsyMQ8bP9HwgflT9GY7+t3qgv6GGy60U3WkXyUzft y2QRhnzNIqxmXRzpHmCxeXoLsRp3InhDN0j8qaIgvu3dA04Bfgut8SANi6lu6rkMzW3pgI LKV731q7vSNqQxqztT4oz4bTfu0RSqc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-635-R_gSd9b2MsSJ8KswrppQmg-1; Fri, 04 Mar 2022 11:47:43 -0500 X-MC-Unique: R_gSd9b2MsSJ8KswrppQmg-1 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 01636824FA7; Fri, 4 Mar 2022 16:47:42 +0000 (UTC) Received: from merkur.redhat.com (unknown [10.39.194.38]) by smtp.corp.redhat.com (Postfix) with ESMTP id 053B583BF9; Fri, 4 Mar 2022 16:47:40 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 19/50] block/export/fuse.c: allow writable exports to take RESIZE permission Date: Fri, 4 Mar 2022 17:46:40 +0100 Message-Id: <20220304164711.474713-20-kwolf@redhat.com> In-Reply-To: <20220304164711.474713-1-kwolf@redhat.com> References: <20220304164711.474713-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@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=170.10.129.124; envelope-from=kwolf@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=-0.082, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Emanuele Giuseppe Esposito Allow writable exports to get BLK_PERM_RESIZE permission from creation, in fuse_export_create(). In this way, there is no need to give the permission in fuse_do_truncate(), which might be run in an iothread. Permissions should be set only in the main thread, so in any case if an iothread tries to set RESIZE, it will be blocked. Also assert in fuse_do_truncate that if we give the RESIZE permission we can then restore the original ones. Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Hanna Reitz Message-Id: <20220303151616.325444-7-eesposit@redhat.com> Signed-off-by: Kevin Wolf --- block/export/fuse.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/block/export/fuse.c b/block/export/fuse.c index fdda8e3c81..5029e70f84 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -86,8 +86,8 @@ static int fuse_export_create(BlockExport *blk_exp, assert(blk_exp_args->type == BLOCK_EXPORT_TYPE_FUSE); - /* For growable exports, take the RESIZE permission */ - if (args->growable) { + /* For growable and writable exports, take the RESIZE permission */ + if (args->growable || blk_exp_args->writable) { uint64_t blk_perm, blk_shared_perm; blk_get_perm(exp->common.blk, &blk_perm, &blk_shared_perm); @@ -392,14 +392,23 @@ static int fuse_do_truncate(const FuseExport *exp, int64_t size, { uint64_t blk_perm, blk_shared_perm; BdrvRequestFlags truncate_flags = 0; - int ret; + bool add_resize_perm; + int ret, ret_check; + + /* Growable and writable exports have a permanent RESIZE permission */ + add_resize_perm = !exp->growable && !exp->writable; if (req_zero_write) { truncate_flags |= BDRV_REQ_ZERO_WRITE; } - /* Growable exports have a permanent RESIZE permission */ - if (!exp->growable) { + if (add_resize_perm) { + + if (!qemu_in_main_thread()) { + /* Changing permissions like below only works in the main thread */ + return -EPERM; + } + blk_get_perm(exp->common.blk, &blk_perm, &blk_shared_perm); ret = blk_set_perm(exp->common.blk, blk_perm | BLK_PERM_RESIZE, @@ -412,9 +421,11 @@ static int fuse_do_truncate(const FuseExport *exp, int64_t size, ret = blk_truncate(exp->common.blk, size, true, prealloc, truncate_flags, NULL); - if (!exp->growable) { + if (add_resize_perm) { /* Must succeed, because we are only giving up the RESIZE permission */ - blk_set_perm(exp->common.blk, blk_perm, blk_shared_perm, &error_abort); + ret_check = blk_set_perm(exp->common.blk, blk_perm, + blk_shared_perm, &error_abort); + assert(ret_check == 0); } return ret; -- 2.35.1