From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36716) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBbdc-0000Wg-A8 for qemu-devel@nongnu.org; Fri, 19 May 2017 02:43:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dBbdb-00049L-9w for qemu-devel@nongnu.org; Fri, 19 May 2017 02:43:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58096) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dBbdb-00049H-0j for qemu-devel@nongnu.org; Fri, 19 May 2017 02:43:47 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DDAB87F4A3 for ; Fri, 19 May 2017 06:43:45 +0000 (UTC) From: Peter Xu Date: Fri, 19 May 2017 14:43:27 +0800 Message-Id: <1495176212-14446-2-git-send-email-peterx@redhat.com> In-Reply-To: <1495176212-14446-1-git-send-email-peterx@redhat.com> References: <1495176212-14446-1-git-send-email-peterx@redhat.com> Subject: [Qemu-devel] [PATCH RFC 1/6] io: only allow return path for socket typed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Juan Quintela , "Dr . David Alan Gilbert" , peterx@redhat.com, "Daniel P . Berrange" We don't really have a return path for the other types yet. Let's check this when .get_return_path() is called. For this, we introduce a new feature bit, and set it up only for socket typed IO channels. This will help detect earlier failure for postcopy, e.g., logically speaking postcopy cannot work with "exec:". Before this patch, when we try to migrate with "migrate -d exec:cat>out", we'll hang the system. With this patch, we'll get: (qemu) migrate -d exec:cat>out Unable to open return-path for postcopy CC: Daniel P. Berrange Signed-off-by: Peter Xu --- include/io/channel.h | 1 + io/channel-socket.c | 1 + migration/qemu-file-channel.c | 9 +++++++++ 3 files changed, 11 insertions(+) diff --git a/include/io/channel.h b/include/io/channel.h index db9bb02..7876534 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -45,6 +45,7 @@ enum QIOChannelFeature { QIO_CHANNEL_FEATURE_FD_PASS, QIO_CHANNEL_FEATURE_SHUTDOWN, QIO_CHANNEL_FEATURE_LISTEN, + QIO_CHANNEL_FEATURE_RETURN_PATH, }; diff --git a/io/channel-socket.c b/io/channel-socket.c index 53386b7..ee81b2d 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -56,6 +56,7 @@ qio_channel_socket_new(void) ioc = QIO_CHANNEL(sioc); qio_channel_set_feature(ioc, QIO_CHANNEL_FEATURE_SHUTDOWN); + qio_channel_set_feature(ioc, QIO_CHANNEL_FEATURE_RETURN_PATH); #ifdef WIN32 ioc->event = CreateEvent(NULL, FALSE, FALSE, NULL); diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c index 45c13f1..3bd7940 100644 --- a/migration/qemu-file-channel.c +++ b/migration/qemu-file-channel.c @@ -23,6 +23,7 @@ */ #include "qemu/osdep.h" +#include "qom/object.h" #include "migration/qemu-file.h" #include "io/channel-socket.h" #include "qemu/iov.h" @@ -139,6 +140,10 @@ static QEMUFile *channel_get_input_return_path(void *opaque) { QIOChannel *ioc = QIO_CHANNEL(opaque); + if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_RETURN_PATH)) { + return NULL; + } + return qemu_fopen_channel_output(ioc); } @@ -146,6 +151,10 @@ static QEMUFile *channel_get_output_return_path(void *opaque) { QIOChannel *ioc = QIO_CHANNEL(opaque); + if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_RETURN_PATH)) { + return NULL; + } + return qemu_fopen_channel_input(ioc); } -- 2.7.4