[libvirt] [PATCH v1 17/21] qemu: Manage /dev entry on disk hotplug
Michal Privoznik
mprivozn at redhat.com
Thu Nov 24 14:48:06 UTC 2016
When attaching a device to a domain that's using separate mount
namespace we must maintain /dev entries in order for qemu process
to see them.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
src/qemu/qemu_domain.c | 215 +++++++++++++++++++++++++++++++++++++++++++++++
src/qemu/qemu_domain.h | 8 ++
src/qemu/qemu_driver.c | 5 +-
src/qemu/qemu_hotplug.c | 22 +++--
src/qemu/qemu_security.c | 36 ++++++++
src/qemu/qemu_security.h | 8 ++
6 files changed, 285 insertions(+), 9 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index b9492a9..a1edde9 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -53,6 +53,11 @@
#include "storage/storage_driver.h"
+#ifdef MAJOR_IN_MKDEV
+# include <sys/mkdev.h>
+#elif MAJOR_IN_SYSMACROS
+# include <sys/sysmacros.h>
+#endif
#include <sys/time.h>
#include <fcntl.h>
#if defined(HAVE_SYS_MOUNT_H)
@@ -7297,3 +7302,213 @@ qemuDomainDeleteNamespace(virQEMUDriverPtr driver,
virObjectUnref(cfg);
VIR_FREE(path);
}
+
+
+struct qemuDomainAttachDeviceMknodData {
+ virQEMUDriverPtr driver;
+ virDomainObjPtr vm;
+ virDomainDeviceDefPtr devDef;
+ const char *file;
+ struct stat sb;
+ void *acl;
+};
+
+
+static int
+qemuDomainAttachDeviceMknodHelper(pid_t pid ATTRIBUTE_UNUSED,
+ void *opaque)
+{
+ struct qemuDomainAttachDeviceMknodData *data = opaque;
+ int ret = -1;
+
+ virSecurityManagerPostFork(data->driver->securityManager);
+
+ if (virFileMakeParentPath(data->file) < 0) {
+ virReportSystemError(errno,
+ _("Unable to create %s"), data->file);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Creating dev %s (%d,%d)",
+ data->file, major(data->sb.st_rdev), minor(data->sb.st_rdev));
+ if (mknod(data->file, data->sb.st_mode, data->sb.st_rdev) < 0) {
+ /* Because we are not removing devices on hotunplug, or
+ * we might be creating part of backing chain that
+ * already exist due to a different disk plugged to
+ * domain, accept EEXIST. */
+ if (errno != EEXIST) {
+ virReportSystemError(errno,
+ _("Unable to create device %s"),
+ data->file);
+ goto cleanup;
+ }
+ }
+
+ if (virFileSetACLs(data->file, data->acl) < 0 &&
+ errno != ENOTSUP) {
+ virReportSystemError(errno,
+ _("Unable to set ACLs on %s"), data->file);
+ goto cleanup;
+ }
+
+ switch ((virDomainDeviceType) data->devDef->type) {
+ case VIR_DOMAIN_DEVICE_DISK: {
+ virDomainDiskDefPtr def = data->devDef->data.disk;
+ char *tmpsrc = def->src->path;
+ def->src->path = (char *) data->file;
+ if (virSecurityManagerSetDiskLabel(data->driver->securityManager,
+ data->vm->def, def) < 0) {
+ def->src->path = tmpsrc;
+ goto cleanup;
+ }
+ def->src->path = tmpsrc;
+ } break;
+
+ case VIR_DOMAIN_DEVICE_NONE:
+ case VIR_DOMAIN_DEVICE_LEASE:
+ case VIR_DOMAIN_DEVICE_FS:
+ case VIR_DOMAIN_DEVICE_NET:
+ case VIR_DOMAIN_DEVICE_INPUT:
+ case VIR_DOMAIN_DEVICE_SOUND:
+ case VIR_DOMAIN_DEVICE_VIDEO:
+ case VIR_DOMAIN_DEVICE_HOSTDEV:
+ case VIR_DOMAIN_DEVICE_WATCHDOG:
+ case VIR_DOMAIN_DEVICE_CONTROLLER:
+ case VIR_DOMAIN_DEVICE_GRAPHICS:
+ case VIR_DOMAIN_DEVICE_HUB:
+ case VIR_DOMAIN_DEVICE_REDIRDEV:
+ case VIR_DOMAIN_DEVICE_SMARTCARD:
+ case VIR_DOMAIN_DEVICE_CHR:
+ case VIR_DOMAIN_DEVICE_MEMBALLOON:
+ case VIR_DOMAIN_DEVICE_NVRAM:
+ case VIR_DOMAIN_DEVICE_RNG:
+ case VIR_DOMAIN_DEVICE_SHMEM:
+ case VIR_DOMAIN_DEVICE_TPM:
+ case VIR_DOMAIN_DEVICE_PANIC:
+ case VIR_DOMAIN_DEVICE_MEMORY:
+ case VIR_DOMAIN_DEVICE_IOMMU:
+ case VIR_DOMAIN_DEVICE_LAST:
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Unexpected device type %d"),
+ data->devDef->type);
+ goto cleanup;
+ }
+
+ ret = 0;
+ cleanup:
+ if (ret < 0)
+ unlink(data->file);
+ virFileFreeACLs(&data->acl);
+ return ret;
+}
+
+
+static int
+qemuDomainAttachDeviceMknod(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDeviceDefPtr devDef,
+ const char *file)
+{
+ struct qemuDomainAttachDeviceMknodData data;
+ int ret = -1;
+
+ memset(&data, 0, sizeof(data));
+
+ data.driver = driver;
+ data.vm = vm;
+ data.devDef = devDef;
+ data.file = file;
+
+ if (stat(file, &data.sb) < 0) {
+ virReportSystemError(errno,
+ _("Unable to access %s"), file);
+ return ret;
+ }
+
+ if (virFileGetACLs(file, &data.acl) < 0 &&
+ errno != ENOTSUP) {
+ virReportSystemError(errno,
+ _("Unable to get ACLs on %s"), file);
+ return ret;
+ }
+
+ if (virSecurityManagerPreFork(driver->securityManager) < 0)
+ goto cleanup;
+
+ if (virProcessRunInMountNamespace(vm->pid,
+ qemuDomainAttachDeviceMknodHelper,
+ &data) < 0) {
+ virSecurityManagerPostFork(driver->securityManager);
+ goto cleanup;
+ }
+
+ virSecurityManagerPostFork(driver->securityManager);
+
+ ret = 0;
+ cleanup:
+ virFileFreeACLs(&data.acl);
+ return 0;
+}
+
+
+int
+qemuDomainNamespaceSetupDisk(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ virDomainDeviceDef dev = {.type = VIR_DOMAIN_DEVICE_DISK, .data.disk = disk};
+ virStorageSourcePtr next;
+ const char *src = NULL;
+ struct stat sb;
+ int ret = -1;
+
+ if (!priv->containerized)
+ return 0;
+
+ for (next = disk->src; next; next = next->backingStore) {
+ if (!next->path || !virStorageSourceIsBlockLocal(disk->src) ||
+ !STRPREFIX(next->path, "/dev")) {
+ /* Not creating device. Just continue. */
+ continue;
+ }
+
+ if (stat(next->path, &sb) < 0) {
+ virReportSystemError(errno,
+ _("Unable to access %s"), src);
+ goto cleanup;
+ }
+
+ if (!S_ISBLK(sb.st_mode)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("Disk source %s must be a block device"),
+ src);
+ goto cleanup;
+ }
+
+ if (qemuDomainAttachDeviceMknod(driver,
+ vm,
+ &dev,
+ next->path) < 0)
+ goto cleanup;
+ }
+
+ ret = 0;
+ cleanup:
+ return ret;
+}
+
+
+int
+qemuDomainNamespaceTeardownDisk(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
+ virDomainObjPtr vm ATTRIBUTE_UNUSED,
+ virDomainDiskDefPtr disk ATTRIBUTE_UNUSED)
+{
+ /* While in hotplug case we create the whole backing chain,
+ * here we must limit ourselves. The disk we want to remove
+ * might be a part of backing chain of another disk.
+ * If you are reading these lines and have some spare time
+ * you can come up with and algorithm that checks for that.
+ * I don't, therefore: */
+ return 0;
+}
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 9c34476..045d1ba 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -795,4 +795,12 @@ int qemuDomainCreateNamespace(virQEMUDriverPtr driver,
void qemuDomainDeleteNamespace(virQEMUDriverPtr driver,
virDomainObjPtr vm);
+
+int qemuDomainNamespaceSetupDisk(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk);
+
+int qemuDomainNamespaceTeardownDisk(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk);
#endif /* __QEMU_DOMAIN_H__ */
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 8c8f969..fcf6dd9 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -57,6 +57,7 @@
#include "qemu_process.h"
#include "qemu_migration.h"
#include "qemu_blockjob.h"
+#include "qemu_security.h"
#include "virerror.h"
#include "virlog.h"
@@ -16093,9 +16094,9 @@ qemuDomainBlockPivot(virQEMUDriverPtr driver,
disk->mirror->format != VIR_STORAGE_FILE_RAW &&
(virDomainLockDiskAttach(driver->lockManager, cfg->uri, vm,
disk) < 0 ||
+ qemuDomainNamespaceSetupDisk(driver, vm, disk) < 0 ||
qemuSetupDiskCgroup(vm, disk) < 0 ||
- virSecurityManagerSetDiskLabel(driver->securityManager, vm->def,
- disk) < 0))
+ qemuSecuritySetDiskLabel(driver, vm, disk) < 0))
goto cleanup;
disk->src = oldsrc;
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 5038ce1..9b47b5f 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -34,6 +34,7 @@
#include "qemu_hostdev.h"
#include "qemu_interface.h"
#include "qemu_process.h"
+#include "qemu_security.h"
#include "domain_audit.h"
#include "netdev_bandwidth_conf.h"
#include "domain_nwfilter.h"
@@ -109,13 +110,15 @@ qemuDomainPrepareDisk(virQEMUDriverPtr driver,
vm, disk) < 0)
goto cleanup;
- if (virSecurityManagerSetDiskLabel(driver->securityManager,
- vm->def, disk) < 0)
+ if (qemuSecuritySetDiskLabel(driver, vm, disk) < 0)
goto rollback_lock;
- if (qemuSetupDiskCgroup(vm, disk) < 0)
+ if (qemuDomainNamespaceSetupDisk(driver, vm, disk) < 0)
goto rollback_label;
+ if (qemuSetupDiskCgroup(vm, disk) < 0)
+ goto rollback_namespace;
+
ret = 0;
goto cleanup;
@@ -123,10 +126,13 @@ qemuDomainPrepareDisk(virQEMUDriverPtr driver,
if (qemuTeardownDiskCgroup(vm, disk) < 0)
VIR_WARN("Unable to tear down cgroup access on %s",
virDomainDiskGetSource(disk));
+ rollback_namespace:
+ if (qemuDomainNamespaceTeardownDisk(driver, vm, disk) < 0)
+ VIR_WARN("Unable to remove /dev entry for %s",
+ virDomainDiskGetSource(disk));
rollback_label:
- if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
- vm->def, disk) < 0)
+ if (qemuSecurityRestoreDiskLabel(driver, vm, disk) < 0)
VIR_WARN("Unable to restore security label on %s",
virDomainDiskGetSource(disk));
@@ -3465,8 +3471,7 @@ qemuDomainRemoveDiskDevice(virQEMUDriverPtr driver,
qemuDomainReleaseDeviceAddress(vm, &disk->info, src);
- if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
- vm->def, disk) < 0)
+ if (qemuSecurityRestoreDiskLabel(driver, vm, disk) < 0)
VIR_WARN("Unable to restore security label on %s", src);
if (qemuTeardownDiskCgroup(vm, disk) < 0)
@@ -3475,6 +3480,9 @@ qemuDomainRemoveDiskDevice(virQEMUDriverPtr driver,
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s", src);
+ if (qemuDomainNamespaceTeardownDisk(driver, vm, disk) < 0)
+ VIR_WARN("Unable to remove /dev entry for %s", src);
+
dev.type = VIR_DOMAIN_DEVICE_DISK;
dev.data.disk = disk;
ignore_value(qemuRemoveSharedDevice(driver, &dev, vm->def->name));
diff --git a/src/qemu/qemu_security.c b/src/qemu/qemu_security.c
index cec7dfd..f800d9b 100644
--- a/src/qemu/qemu_security.c
+++ b/src/qemu/qemu_security.c
@@ -132,3 +132,39 @@ qemuSecurityRestoreAllLabel(virQEMUDriverPtr driver,
migrated);
}
}
+
+
+int
+qemuSecuritySetDiskLabel(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+
+ if (priv->containerized) {
+ /* Already handled by namespace code. */
+ return 0;
+ }
+
+ return virSecurityManagerSetDiskLabel(driver->securityManager,
+ vm->def,
+ disk);
+}
+
+
+int
+qemuSecurityRestoreDiskLabel(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+
+ if (priv->containerized) {
+ /* Already handled by namespace code. */
+ return 0;
+ }
+
+ return virSecurityManagerRestoreDiskLabel(driver->securityManager,
+ vm->def,
+ disk);
+}
diff --git a/src/qemu/qemu_security.h b/src/qemu/qemu_security.h
index 88c53e7..e3324ca 100644
--- a/src/qemu/qemu_security.h
+++ b/src/qemu/qemu_security.h
@@ -36,4 +36,12 @@ int qemuSecuritySetAllLabel(virQEMUDriverPtr driver,
void qemuSecurityRestoreAllLabel(virQEMUDriverPtr driver,
virDomainObjPtr vm,
bool migrated);
+
+int qemuSecuritySetDiskLabel(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk);
+
+int qemuSecurityRestoreDiskLabel(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk);
#endif /* __QEMU_SECURITY_H__ */
--
2.8.4
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