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qemu: hotplug: Add helper to initialize/teardown new disks for VMs

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When we are changing media (or doing other hotplug operations) we need
to setup cgroups, locking and seclabels on the new disk. This is a
multi-step process where every piece can fail. To simplify dealing with
this introduce qemuDomainPrepareDisk that similarly to
qemuDomainPrepareDiskChainElement initializes/tears down  a whole new
disk to be used with the domain.

Additionally the function supports passing a different source struct for
media changes of cdroms that will be refactored later.
This commit is contained in:
Peter Krempa 2014-08-05 14:53:01 +02:00
parent 240eb2fb89
commit ca91ba78bd
2 changed files with 85 additions and 67 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/qemu/qemu_driver.c
View File

@ -6648,9 +6648,6 @@ qemuDomainChangeDiskMediaLive(virConnectPtr conn,
if (qemuDomainDetermineDiskChain(driver, vm, disk, false) < 0)
goto end;
if (qemuSetupDiskCgroup(vm, disk) < 0)
goto end;
switch (disk->device) {
case VIR_DOMAIN_DISK_DEVICE_CDROM:
case VIR_DOMAIN_DISK_DEVICE_FLOPPY:
@ -6701,11 +6698,6 @@ qemuDomainChangeDiskMediaLive(virConnectPtr conn,
break;
}
if (ret != 0 &&
qemuTeardownDiskCgroup(vm, disk) < 0)
VIR_WARN("Failed to teardown cgroup for disk path %s",
NULLSTR(virDomainDiskGetSource(disk)));
end:
virObjectUnref(caps);
virDomainDeviceDefFree(dev_copy);

144
src/qemu/qemu_hotplug.c
View File

@ -61,6 +61,83 @@ VIR_LOG_INIT("qemu.qemu_hotplug");
unsigned long long qemuDomainRemoveDeviceWaitTime = 1000ull * 5;
/**
* qemuDomainPrepareDisk:
* @driver: qemu driver struct
* @vm: domain object
* @disk: disk to prepare
* @overridesrc: Source different than @disk->src when necessary
* @teardown: Teardown the disk instead of adding it to a vm
*
* Setup the locks, cgroups and security permissions on a disk of a VM.
* If @overridesrc is specified the source struct is used instead of the
* one present in @disk. If @teardown is true, then the labels and cgroups
* are removed instead.
*
* Returns 0 on success and -1 on error. Reports libvirt error.
*/
static int
qemuDomainPrepareDisk(virQEMUDriverPtr driver,
virDomainObjPtr vm,
virDomainDiskDefPtr disk,
virStorageSourcePtr overridesrc,
bool teardown)
{
virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
int ret = -1;
virStorageSourcePtr origsrc = NULL;
if (overridesrc) {
origsrc = disk->src;
disk->src = overridesrc;
}
/* just tear down the disk access */
if (teardown) {
ret = 0;
goto rollback_cgroup;
}
if (virDomainLockDiskAttach(driver->lockManager, cfg->uri,
vm, disk) < 0)
goto cleanup;
if (virSecurityManagerSetDiskLabel(driver->securityManager,
vm->def, disk) < 0)
goto rollback_lock;
if (qemuSetupDiskCgroup(vm, disk) < 0)
goto rollback_label;
ret = 0;
goto cleanup;
rollback_cgroup:
if (qemuTeardownDiskCgroup(vm, disk) < 0)
VIR_WARN("Unable to tear down cgroup access on %s",
virDomainDiskGetSource(disk));
rollback_label:
if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
vm->def, disk) < 0)
VIR_WARN("Unable to restore security label on %s",
virDomainDiskGetSource(disk));
rollback_lock:
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s",
virDomainDiskGetSource(disk));
cleanup:
if (origsrc)
disk->src = origsrc;
virObjectUnref(cfg);
return ret;
}
int qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
virDomainObjPtr vm,
virDomainDiskDefPtr disk,
@ -88,18 +165,9 @@ int qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
goto cleanup;
}
if (virDomainLockDiskAttach(driver->lockManager, cfg->uri,
vm, disk) < 0)
if (qemuDomainPrepareDisk(driver, vm, disk, NULL, false) < 0)
goto cleanup;
if (virSecurityManagerSetDiskLabel(driver->securityManager,
vm->def, disk) < 0) {
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s",
virDomainDiskGetSource(disk));
goto cleanup;
}
if (!(driveAlias = qemuDeviceDriveHostAlias(origdisk, priv->qemuCaps)))
goto error;
@ -160,14 +228,7 @@ int qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
if (ret < 0)
goto error;
if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
vm->def, origdisk) < 0)
VIR_WARN("Unable to restore security label on ejected image %s",
virDomainDiskGetSource(origdisk));
if (virDomainLockDiskDetach(driver->lockManager, vm, origdisk) < 0)
VIR_WARN("Unable to release lock on disk %s",
virDomainDiskGetSource(origdisk));
ignore_value(qemuDomainPrepareDisk(driver, vm, origdisk, NULL, true));
if (virDomainDiskSetSource(origdisk, src) < 0)
goto error;
@ -183,12 +244,7 @@ int qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
error:
virDomainAuditDisk(vm, origdisk->src, disk->src, "update", false);
if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
vm->def, disk) < 0)
VIR_WARN("Unable to restore security label on new media %s", src);
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s", src);
ignore_value(qemuDomainPrepareDisk(driver, vm, disk, NULL, true));
goto cleanup;
}
@ -267,17 +323,9 @@ qemuDomainAttachVirtioDiskDevice(virConnectPtr conn,
}
}
if (virDomainLockDiskAttach(driver->lockManager, cfg->uri,
vm, disk) < 0)
if (qemuDomainPrepareDisk(driver, vm, disk, NULL, false) < 0)
goto cleanup;
if (virSecurityManagerSetDiskLabel(driver->securityManager,
vm->def, disk) < 0) {
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s", src);
goto cleanup;
}
if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
if (disk->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW) {
if (virDomainCCWAddressAssign(&disk->info, priv->ccwaddrs,
@ -348,6 +396,8 @@ qemuDomainAttachVirtioDiskDevice(virConnectPtr conn,
if (releaseaddr)
qemuDomainReleaseDeviceAddress(vm, &disk->info, src);
ignore_value(qemuDomainPrepareDisk(driver, vm, disk, NULL, true));
if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
vm->def, disk) < 0)
VIR_WARN("Unable to restore security label on %s", src);
@ -496,7 +546,6 @@ qemuDomainAttachSCSIDisk(virConnectPtr conn,
char *devstr = NULL;
int ret = -1;
virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
const char *src = virDomainDiskGetSource(disk);
for (i = 0; i < vm->def->ndisks; i++) {
if (STREQ(vm->def->disks[i]->dst, disk->dst)) {
@ -506,17 +555,9 @@ qemuDomainAttachSCSIDisk(virConnectPtr conn,
}
}
if (virDomainLockDiskAttach(driver->lockManager, cfg->uri,
vm, disk) < 0)
if (qemuDomainPrepareDisk(driver, vm, disk, NULL, false) < 0)
goto cleanup;
if (virSecurityManagerSetDiskLabel(driver->securityManager,
vm->def, disk) < 0) {
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s", src);
goto cleanup;
}
/* We should have an address already, so make sure */
if (disk->info.type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DRIVE) {
virReportError(VIR_ERR_INTERNAL_ERROR,
@ -598,13 +639,7 @@ qemuDomainAttachSCSIDisk(virConnectPtr conn,
return ret;
error:
if (virSecurityManagerRestoreDiskLabel(driver->securityManager,
vm->def, disk) < 0)
VIR_WARN("Unable to restore security label on %s", src);
if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
VIR_WARN("Unable to release lock on %s", src);
ignore_value(qemuDomainPrepareDisk(driver, vm, disk, NULL, true));
goto cleanup;
}
@ -737,9 +772,6 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
if (qemuDomainDetermineDiskChain(driver, vm, disk, false) < 0)
goto end;
if (qemuSetupDiskCgroup(vm, disk) < 0)
goto end;
switch (disk->device) {
case VIR_DOMAIN_DISK_DEVICE_CDROM:
case VIR_DOMAIN_DISK_DEVICE_FLOPPY:
@ -806,12 +838,6 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
break;
}
if (ret != 0 &&
qemuTeardownDiskCgroup(vm, disk) < 0) {
VIR_WARN("Failed to teardown cgroup for disk path %s",
NULLSTR(src));
}
end:
if (ret != 0)
ignore_value(qemuRemoveSharedDevice(driver, dev, vm->def->name));