When a user does not explicitly set a <driver> in the disk config, libvirt defers selection of a default to libxl. This approach works fine when starting a domain with such configuration or attaching a disk to a running domain. But when detaching such a disk, libxl will fail with "unrecognized disk backend type: 0". libxl makes no attempt to recalculate a default backend (driver) on detach and simply fails when uninitialized. This patch updates the libvirt disk config with the backend selected by libxl when starting a domain or attaching a disk to a running domain. Another benefit of this approach is that the live XML is also updated with the backend driver selected by libxl. Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; --- src/libxl/libxl_conf.c | 33 +++++++++++++++++++++++++++++++++ src/libxl/libxl_conf.h | 4 ++++ src/libxl/libxl_domain.c | 25 +++++++++++++++++++++++++ src/libxl/libxl_driver.c | 2 +- 4 files changed, 63 insertions(+), 1 deletion(-) diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index b5186f2..6ef7570 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -851,6 +851,7 @@ libxlMakeDisk(virDomainDiskDefPtr l_disk, libxl_device_disk *x_disk) * xl-disk-configuration.txt in the xen documentation and let * libxl pick a suitable backend. */ + virDomainDiskSetFormat(l_disk, VIR_STORAGE_FILE_RAW); x_disk->format = LIBXL_DISK_FORMAT_RAW; x_disk->backend = LIBXL_DISK_BACKEND_UNKNOWN; } @@ -913,6 +914,38 @@ libxlMakeDiskList(virDomainDefPtr def, libxl_domain_config *d_config) return -1; } +/* + * Update libvirt disk config with libxl disk config. + * + * This function can be used to update the libvirt disk config with default + * values selected by libxl. Currently only the backend type is selected by + * libxl when not explicitly specified by the user. + */ +void +libxlUpdateDisk(virDomainDiskDefPtr l_disk, libxl_device_disk *x_disk) +{ + const char *driver = NULL; + + if (virDomainDiskGetDriver(l_disk)) + return; + + switch (x_disk->backend) { + case LIBXL_DISK_BACKEND_QDISK: + driver = "qemu"; + break; + case LIBXL_DISK_BACKEND_TAP: + driver = "tap"; + break; + case LIBXL_DISK_BACKEND_PHY: + driver = "phy"; + break; + case LIBXL_DISK_BACKEND_UNKNOWN: + break; + } + if (driver) + ignore_value(virDomainDiskSetDriver(l_disk, driver)); +} + int libxlMakeNic(virDomainDefPtr def, virDomainNetDefPtr l_nic, diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 69d7885..732a1d2 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -175,6 +175,10 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg, int libxlMakeDisk(virDomainDiskDefPtr l_dev, libxl_device_disk *x_dev); + +void +libxlUpdateDisk(virDomainDiskDefPtr l_dev, libxl_device_disk *x_dev); + int libxlMakeNic(virDomainDefPtr def, virDomainNetDefPtr l_nic, diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index ed73cd2..0168777 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -1067,6 +1067,30 @@ libxlDomainCreateIfaceNames(virDomainDefPtr def, libxl_domain_config *d_config) } } +static void +libxlDomainUpdateDiskParams(virDomainDefPtr def, libxl_ctx *ctx) +{ + libxl_device_disk *disks; + int num_disks = 0; + size_t i; + int idx; + + disks = libxl_device_disk_list(ctx, def->id, &num_disks); + if (!disks) + return; + + for (i = 0; i < num_disks; i++) { + if ((idx = virDomainDiskIndexByName(def, disks[i].vdev, false)) < 0) + continue; + + libxlUpdateDisk(def->disks[idx], &disks[i]); + } + + for (i = 0; i < num_disks; i++) + libxl_device_disk_dispose(&disks[i]); + VIR_FREE(disks); +} + #ifdef LIBXL_HAVE_DEVICE_CHANNEL static void libxlDomainCreateChannelPTY(virDomainDefPtr def, libxl_ctx *ctx) @@ -1310,6 +1334,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver, goto destroy_dom; libxlDomainCreateIfaceNames(vm->def, &d_config); + libxlDomainUpdateDiskParams(vm->def, cfg->ctx); #ifdef LIBXL_HAVE_DEVICE_CHANNEL if (vm->def->nchannels > 0) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 3a69720..6dddf9f 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -3027,7 +3027,7 @@ libxlDomainAttachDeviceDiskLive(virDomainObjPtr vm, virDomainDeviceDefPtr dev) } goto cleanup; } - + libxlUpdateDisk(l_disk, &x_disk); virDomainDiskInsertPreAlloced(vm->def, l_disk); } else { -- 2.9.2