Re: [libvirt] [PATCH v2 2/3] qemu: Handle device mapper targets properly

https://bugzilla.redhat.com/show_bug.cgi?id=1557769 Problem with device mapper targets is that there can be several other devices 'hidden' behind them. For instance, /dev/dm-1 can consist of /dev/sda, /dev/sdb and /dev/sdc. Therefore, when setting up devices CGroup and namespaces we have to take this into account. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- libvirt.spec.in | 2 ++ src/qemu/qemu_cgroup.c | 42 ++++++++++++++++++++++++++++++--- src/qemu/qemu_domain.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 105 insertions(+), 3 deletions(-) diff --git a/libvirt.spec.in b/libvirt.spec.in index b55a947ec9..ebfac10866 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -796,6 +796,8 @@ Requires: gzip Requires: bzip2 Requires: lzop Requires: xz +# For mpath devices +Requires: device-mapper %if 0%{?fedora} || 0%{?rhel} > 7 Requires: systemd-container %endif diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c index b604edb31c..e17b3d21b5 100644 --- a/src/qemu/qemu_cgroup.c +++ b/src/qemu/qemu_cgroup.c @@ -37,6 +37,7 @@ #include "virtypedparam.h" #include "virnuma.h" #include "virsystemd.h" +#include "virdevmapper.h" #define VIR_FROM_THIS VIR_FROM_QEMU @@ -60,7 +61,13 @@ qemuSetupImagePathCgroup(virDomainObjPtr vm, { qemuDomainObjPrivatePtr priv = vm->privateData; int perms = VIR_CGROUP_DEVICE_READ; - int ret; + unsigned int *maj = NULL; + unsigned int *min = NULL; + size_t nmaj = 0; + size_t i; + char *devPath = NULL; + int rv; + int ret = -1; if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_DEVICES)) return 0; @@ -71,12 +78,41 @@ qemuSetupImagePathCgroup(virDomainObjPtr vm, VIR_DEBUG("Allow path %s, perms: %s", path, virCgroupGetDevicePermsString(perms)); - ret = virCgroupAllowDevicePath(priv->cgroup, path, perms, true); + rv = virCgroupAllowDevicePath(priv->cgroup, path, perms, true); virDomainAuditCgroupPath(vm, priv->cgroup, "allow", path, virCgroupGetDevicePermsString(perms), - ret); + rv); + if (rv < 0) + goto cleanup; + if (virDevMapperGetTargets(path, &maj, &min, &nmaj) < 0 && + errno != ENOSYS && errno != EBADF) { + virReportSystemError(errno, + _("Unable to get devmapper targets for %s"), + path); + goto cleanup; + } + + for (i = 0; i < nmaj; i++) { + if (virAsprintf(&devPath, "/dev/block/%u:%u", maj[i], min[i]) < 0) + goto cleanup;

+ + rv = virCgroupAllowDevicePath(priv->cgroup, devPath, perms, true);

+ + virDomainAuditCgroupPath(vm, priv->cgroup, "allow", devPath, + virCgroupGetDevicePermsString(perms), + rv);

+ if (rv < 0) + goto cleanup; + VIR_FREE(devPath); + } + + ret = 0; + cleanup: + VIR_FREE(devPath); + VIR_FREE(min); + VIR_FREE(maj); return ret; } diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 580e0f830d..5f56324502 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -54,6 +54,7 @@ #include "secret_util.h" #include "logging/log_manager.h" #include "locking/domain_lock.h" +#include "virdevmapper.h" #ifdef MAJOR_IN_MKDEV # include <sys/mkdev.h> @@ -10108,6 +10109,11 @@ qemuDomainSetupDisk(virQEMUDriverConfigPtr cfg ATTRIBUTE_UNUSED, { virStorageSourcePtr next; char *dst = NULL; + unsigned int *maj = NULL; + unsigned int *min = NULL; + size_t nmaj = 0; + char *devPath = NULL; + size_t i; int ret = -1; for (next = disk->src; virStorageSourceIsBacking(next); next = next->backingStore) { @@ -10118,10 +10124,31 @@ qemuDomainSetupDisk(virQEMUDriverConfigPtr cfg ATTRIBUTE_UNUSED, if (qemuDomainCreateDevice(next->path, data, false) < 0) goto cleanup; + + if (virDevMapperGetTargets(next->path, &maj, &min, &nmaj) < 0 && + errno != ENOSYS && errno != EBADF) { + virReportSystemError(errno, + _("Unable to get mpath targets for %s"), + next->path); + goto cleanup; + } + + for (i = 0; i < nmaj; i++) { + if (virAsprintf(&devPath, "/dev/block/%u:%u", maj[i], min[i]) < 0) + goto cleanup; + + if (qemuDomainCreateDevice(devPath, data, false) < 0) + goto cleanup;