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Tue, 21 Jan 2020 12:31:52 +0000 (UTC) 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= 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 Content-Transfer-Encoding: quoted-printable 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" 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. Berrang=C3=A9 --- 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 i= no, struct fuse_file_info *fi) { struct lo_data *lo =3D lo_data(req); - int fd; + struct lo_map_elem *elem; + int fd =3D -1; =20 (void)ino; =20 - fd =3D lo_fi_fd(req, fi); - pthread_mutex_lock(&lo->mutex); - lo_map_remove(&lo->fd_map, fi->fh); + elem =3D lo_map_get(&lo->fd_map, fi->fh); + if (elem) { + fd =3D elem->fd; + elem =3D NULL; + lo_map_remove(&lo->fd_map, fi->fh); + } pthread_mutex_unlock(&lo->mutex); =20 close(fd); --=20 2.24.1