From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: [PATCH v4 7/8] xl/libxl: implement QDISK libxl_device_disk_local_attach Date: Tue, 24 Apr 2012 11:45:57 +0100 Message-ID: <1335264358-20182-7-git-send-email-stefano.stabellini@eu.citrix.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xensource.com Cc: Ian.Jackson@eu.citrix.com, Ian.Campbell@citrix.com, Stefano Stabellini List-Id: xen-devel@lists.xenproject.org - Spawn a QEMU instance at boot time to handle disk local attach requests. - Implement libxl_device_disk_local_attach for QDISKs in terms of a regular disk attach with the frontend and backend running in the same domain. Changes on v4: - improve error handling and exit paths in libxl__device_disk_local_attach. Signed-off-by: Stefano Stabellini --- tools/hotplug/Linux/init.d/sysconfig.xencommons | 3 + tools/hotplug/Linux/init.d/xencommons | 3 + tools/libxl/libxl_internal.c | 63 +++++++++++++++++++---- tools/libxl/libxl_internal.h | 2 + 4 files changed, 60 insertions(+), 11 deletions(-) diff --git a/tools/hotplug/Linux/init.d/sysconfig.xencommons b/tools/hotplug/Linux/init.d/sysconfig.xencommons index 6543204..0f3b9ad 100644 --- a/tools/hotplug/Linux/init.d/sysconfig.xencommons +++ b/tools/hotplug/Linux/init.d/sysconfig.xencommons @@ -12,3 +12,6 @@ # Running xenbackendd in debug mode #XENBACKENDD_DEBUG=[yes|on|1] + +# qemu path and log file +#QEMU_XEN=/usr/lib/xen/bin/qemu-system-i386 diff --git a/tools/hotplug/Linux/init.d/xencommons b/tools/hotplug/Linux/init.d/xencommons index 2f81ea2..9dda6e2 100644 --- a/tools/hotplug/Linux/init.d/xencommons +++ b/tools/hotplug/Linux/init.d/xencommons @@ -104,6 +104,9 @@ do_start () { xenconsoled --pid-file=$XENCONSOLED_PIDFILE $XENCONSOLED_ARGS test -z "$XENBACKENDD_DEBUG" || XENBACKENDD_ARGS="-d" test "`uname`" != "NetBSD" || xenbackendd $XENBACKENDD_ARGS + echo Starting QEMU as disk backend for dom0 + test -z "$QEMU_XEN" && QEMU_XEN=/usr/lib/xen/bin/qemu-system-i386 + $QEMU_XEN -xen-domid 0 -xen-attach -name dom0 -nographic -M xenpv -daemonize -monitor /dev/null } do_stop () { echo Stopping xenconsoled diff --git a/tools/libxl/libxl_internal.c b/tools/libxl/libxl_internal.c index ac73070..bb75491 100644 --- a/tools/libxl/libxl_internal.c +++ b/tools/libxl/libxl_internal.c @@ -510,6 +510,7 @@ _hidden char * libxl__device_disk_local_attach(libxl__gc *gc, libxl_ctx *ctx = gc->owner; char *dev = NULL; int rc; + xs_transaction_t t = XBT_NULL; libxl_device_disk *tmpdisk = libxl__zalloc(gc, sizeof(libxl_device_disk)); if (tmpdisk == NULL) goto out; @@ -554,13 +555,40 @@ _hidden char * libxl__device_disk_local_attach(libxl__gc *gc, break; case LIBXL_DISK_BACKEND_QDISK: if (tmpdisk->format != LIBXL_DISK_FORMAT_RAW) { - LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "cannot locally" - " attach a qdisk image if the format is not raw"); - break; + do { + t = xs_transaction_start(ctx->xsh); + if (t == XBT_NULL) { + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, + "failed to start a xenstore transaction"); + goto out; + } + tmpdisk->vdev = libxl__alloc_vdev(gc, + LIBXL_TOOLSTACK_DOMID, blkdev_start, t); + if (tmpdisk->vdev == NULL) { + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, + "libxl__alloc_vdev failed\n"); + goto out; + } + if (libxl__device_disk_add_t(gc, LIBXL_TOOLSTACK_DOMID, + t, tmpdisk)) { + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, + "libxl_device_disk_add failed\n"); + goto out; + } + rc = xs_transaction_end(ctx->xsh, t, 0); + } while (rc == 0 && errno == EAGAIN); + t = XBT_NULL; + if (rc == 0) { + LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, + "xenstore transaction failed"); + goto out; + } + dev = GCSPRINTF("/dev/%s", tmpdisk->vdev); + } else { + dev = tmpdisk->pdev_path; } LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching qdisk %s\n", - disk->pdev_path); - dev = tmpdisk->pdev_path; + dev); break; default: LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend " @@ -569,17 +597,30 @@ _hidden char * libxl__device_disk_local_attach(libxl__gc *gc, } out: + if (t != XBT_NULL) + xs_transaction_end(ctx->xsh, t, 1); return dev; } _hidden int libxl__device_disk_local_detach(libxl__gc *gc, libxl_device_disk *disk) { - /* Nothing to do for PHYSTYPE_PHY. */ - - /* - * For other device types assume that the blktap2 process is - * needed by the soon to be started domain and do nothing. - */ + switch (disk->backend) { + case LIBXL_DISK_BACKEND_QDISK: + if (disk->vdev != NULL) { + libxl_device_disk_remove(gc->owner, LIBXL_TOOLSTACK_DOMID, + disk, 0); + return libxl_device_disk_destroy(gc->owner, + LIBXL_TOOLSTACK_DOMID, disk); + } + break; + default: + /* + * Nothing to do for PHYSTYPE_PHY. + * For other device types assume that the blktap2 process is + * needed by the soon to be started domain and do nothing. + */ + break; + } return 0; } diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h index ed145ab..dfd7b49 100644 --- a/tools/libxl/libxl_internal.h +++ b/tools/libxl/libxl_internal.h @@ -77,6 +77,8 @@ #define LIBXL_PV_EXTRA_MEMORY 1024 #define LIBXL_HVM_EXTRA_MEMORY 2048 #define LIBXL_MIN_DOM0_MEM (128*1024) +/* use 0 as the domid of the toolstack domain for now */ +#define LIBXL_TOOLSTACK_DOMID 0 #define QEMU_SIGNATURE "DeviceModelRecord0002" #define STUBDOM_CONSOLE_LOGGING 0 #define STUBDOM_CONSOLE_SAVE 1 -- 1.7.2.5