From 18b76e4c0286f04a5922197b8d40ab7a71437f86 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Tue, 29 May 2012 16:36:51 +0100 Subject: [PATCH] xl/libxl: implement QDISK libxl_device_disk_local_attach - 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. Signed-off-by: Stefano Stabellini Acked-by: Ian Campbell Acked-by: Ian Jackson Committed-by: Ian Campbell --- .../hotplug/Linux/init.d/sysconfig.xencommons | 3 + tools/hotplug/Linux/init.d/xencommons | 3 + tools/libxl/libxl.c | 63 +++++++++++++++---- 3 files changed, 57 insertions(+), 12 deletions(-) diff --git a/tools/hotplug/Linux/init.d/sysconfig.xencommons b/tools/hotplug/Linux/init.d/sysconfig.xencommons index 6543204597..38ea85a699 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 +#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 2f81ea2d90..9dda6e22ba 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.c b/tools/libxl/libxl.c index c7a1976706..44e6dece72 100644 --- a/tools/libxl/libxl.c +++ b/tools/libxl/libxl.c @@ -1783,7 +1783,8 @@ char * libxl__device_disk_local_attach(libxl__gc *gc, libxl_ctx *ctx = gc->owner; char *dev = NULL; char *ret = NULL; - int rc; + int rc, xs_ret; + xs_transaction_t t = XBT_NULL; if (in_disk->pdev_path == NULL) return NULL; @@ -1827,12 +1828,34 @@ char * libxl__device_disk_local_attach(libxl__gc *gc, break; case LIBXL_DISK_BACKEND_QDISK: if (disk->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) { + LOG(ERROR, "failed to start a xenstore transaction"); + goto out; + } + disk->vdev = libxl__alloc_vdev(gc, blkdev_start, t); + if (disk->vdev == NULL) { + LOG(ERROR, "libxl__alloc_vdev failed"); + goto out; + } + if (libxl__device_disk_add(gc, LIBXL_TOOLSTACK_DOMID, + t, disk)) { + LOG(ERROR, "libxl_device_disk_add failed"); + goto out; + } + xs_ret = xs_transaction_end(ctx->xsh, t, 0); + } while (xs_ret == 0 && errno == EAGAIN); + t = XBT_NULL; + if (xs_ret == 0) { + LOGE(ERROR, "xenstore transaction failed"); + goto out; + } + dev = GCSPRINTF("/dev/%s", disk->vdev); + } else { + dev = disk->pdev_path; } - LOG(DEBUG, "locally attaching qdisk %s", in_disk->pdev_path); - dev = disk->pdev_path; + LOG(DEBUG, "locally attaching qdisk %s", dev); break; default: LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend " @@ -1841,6 +1864,8 @@ char * libxl__device_disk_local_attach(libxl__gc *gc, } out: + if (t != XBT_NULL) + xs_transaction_end(ctx->xsh, t, 1); if (dev != NULL) ret = strdup(dev); return ret; @@ -1848,14 +1873,28 @@ char * libxl__device_disk_local_attach(libxl__gc *gc, int libxl__device_disk_local_detach(libxl__gc *gc, libxl_device_disk *disk) { - /* Nothing to do for PHYSTYPE_PHY. */ + int rc = 0; - /* - * 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); + rc = 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; + + return rc; } /******************************************************************************/ -- 2.39.5