From patchwork Tue Jan 21 12:24:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 11343955 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2F1071580 for ; Tue, 21 Jan 2020 13:46:13 +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 01719217F4 for ; Tue, 21 Jan 2020 13:46:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="O5NAyNwF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01719217F4 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:54086 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ittr9-0002Xf-MS for patchwork-qemu-devel@patchwork.kernel.org; Tue, 21 Jan 2020 08:46:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52710) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itshP-00037H-Bl for qemu-devel@nongnu.org; Tue, 21 Jan 2020 07:32:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1itshK-0004iU-5S for qemu-devel@nongnu.org; Tue, 21 Jan 2020 07:32:03 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:59445 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 1itshJ-0004hy-WA for qemu-devel@nongnu.org; Tue, 21 Jan 2020 07:31:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579609916; 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=1nK8DajHPxx37EGUnyFJItEZZkZZwLpJ/80iUHnoJhM=; b=O5NAyNwFCZKtMCX5Y74dpt/JvwpyEdtJ6K3DGo/Pplf119uhPSPewC05A5gmi9VycKhSmB dXptmSiy9AoKHNp7MzwtFPKnUBspgRDtzdrAlOQswvZ+7jJvsCsJpsrbTt6uB5NE9pm3eu rR2GZ5RwTKNisY8D8VUsZcaGHjUeQy8= 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-210-Wp100HFRP4K0Ngrjkq62-g-1; Tue, 21 Jan 2020 07:31:55 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 761501137844; Tue, 21 Jan 2020 12:31:54 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.36.118.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id BDB5B60BE0; Tue, 21 Jan 2020 12:31:52 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com, berrange@redhat.com, slp@redhat.com, philmd@redhat.com Subject: [PATCH v2 089/109] virtiofsd: make lo_release() atomic Date: Tue, 21 Jan 2020 12:24:13 +0000 Message-Id: <20200121122433.50803-90-dgilbert@redhat.com> In-Reply-To: <20200121122433.50803-1-dgilbert@redhat.com> References: <20200121122433.50803-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: Wp100HFRP4K0Ngrjkq62-g-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: m.mizuma@jp.fujitsu.com, misono.tomohiro@jp.fujitsu.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Stefan Hajnoczi Hold the lock across both lo_map_get() and lo_map_remove() to prevent races between two FUSE_RELEASE requests. In this case I don't see a serious bug but it's safer to do things atomically. Signed-off-by: Stefan Hajnoczi Reviewed-by: Daniel P. Berrangé --- tools/virtiofsd/passthrough_ll.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index d7386d8a13..c52f7c2c32 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -1772,14 +1772,18 @@ static void lo_release(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) { struct lo_data *lo = lo_data(req); - int fd; + struct lo_map_elem *elem; + int fd = -1; (void)ino; - fd = lo_fi_fd(req, fi); - pthread_mutex_lock(&lo->mutex); - lo_map_remove(&lo->fd_map, fi->fh); + elem = lo_map_get(&lo->fd_map, fi->fh); + if (elem) { + fd = elem->fd; + elem = NULL; + lo_map_remove(&lo->fd_map, fi->fh); + } pthread_mutex_unlock(&lo->mutex); close(fd);