On 02/06/2013 08:52 AM, Michal Privoznik wrote:
> We need to start NBD server and feed it with all non-<shared/>,
> RW and source-full disks. Moreover, with new virPortAllocator we
> must ensure the borrowed port for NBD server will be returned if
> either migration completes or qemu process is teared down.
> ---
> src/qemu/qemu_migration.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++-
> src/qemu/qemu_process.c | 5 +++
> 2 files changed, 88 insertions(+), 1 deletion(-)
>
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index c71021d..16840b2 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -35,6 +35,7 @@
> #include "qemu_domain.h"
> #include "qemu_process.h"
> #include "qemu_capabilities.h"
> +#include "qemu_command.h"
> #include "qemu_cgroup.h"
>
> #include "domain_audit.h"
> @@ -1091,6 +1092,80 @@ error:
> return NULL;
> }
>
> +/**
> + * qemuMigrationStartNBDServer:
> + * @driver: qemu driver
> + * @vm: domain
> + *
> + * Starts NBD server. This is a newer method to copy
> + * storage during migration than using 'blk' and 'inc'
> + * arguments in 'migrate' monitor command.
> + * Error is reported here.
> + *
> + * Returns 0 on success, -1 otherwise.
> + */
> +static int
> +qemuMigrationStartNBDServer(virQEMUDriverPtr driver,
> + virDomainObjPtr vm)
> +{
> + int ret = -1;
> + qemuDomainObjPrivatePtr priv = vm->privateData;
> + unsigned short port = 0;
> + const char *listen = "0.0.0.0";
> + char *diskAlias = NULL;
> + size_t i;
> +
> + for (i = 0; i < vm->def->ndisks; i++) {
> + virDomainDiskDefPtr disk = vm->def->disks[i];
> +
> + /* skip shared, RO and source-less disks */
> + if (disk->shared || disk->readonly || !disk->src)
> + continue;
> +
> + VIR_FREE(diskAlias);
> + if (virAsprintf(&diskAlias, "%s%s",
> + QEMU_DRIVE_HOST_PREFIX, disk->info.alias) < 0) {
> + virReportOOMError();
> + goto cleanup;
> + }
> +
> + if (qemuDomainObjEnterMonitorAsync(driver, vm,
> + QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
> + goto cleanup;
> +
> + if (!port) {
> + if (virPortAllocatorAcquire(driver->remotePorts, &port) < 0)
> + goto cleanup;
> +
> + if (qemuMonitorNBDServerStart(priv->mon, listen, port) < 0) {
> + qemuDomainObjExitMonitorWithDriver(driver, vm);
> + virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> + _("Unable to start nbd server"));
> + goto cleanup;
> + }
> + }
> +
> + if (qemuMonitorNBDServerAdd(priv->mon, diskAlias, true) < 0) {
> + qemuDomainObjExitMonitorWithDriver(driver, vm);
> +
> + virReportError(VIR_ERR_OPERATION_FAILED,
> + _("Unable to add '%s' to NDB server"), diskAlias);
> + goto cleanup;
> + }
> + qemuDomainObjExitMonitorWithDriver(driver, vm);
> + }
> +
> + priv->nbdPort = port;
> + ret = 0;
> +
> +cleanup:
> + VIR_FREE(diskAlias);
> + if (ret < 0)
> + virPortAllocatorRelease(driver->remotePorts, port);
I believe you can get here with driver->remotePorts not yet allocated
which will cause issues in the Release routine.
Perhaps follow what you did below and use "&& port" to indicate that you
have a port value.
> + return ret;
> +}
> +
> +
> /* Validate whether the domain is safe to migrate. If vm is NULL,
> * then this is being run in the v2 Prepare stage on the destination
> * (where we only have the target xml); if vm is provided, then this
> @@ -1809,8 +1884,11 @@ done:
> if (flags & VIR_MIGRATE_TUNNELLED)
> VIR_DEBUG("NBD in tunnelled migration is currently not supported");
> else {
> + if (qemuMigrationStartNBDServer(driver, vm) < 0) {
> + /* error already reported */
> + goto endjob;
> + }
> cookieFlags |= QEMU_MIGRATION_COOKIE_NBD;
> - priv->nbdPort = 0;
> }
> }
>
> @@ -1857,6 +1935,10 @@ cleanup:
> virObjectUnlock(vm);
> else
> qemuDomainRemoveInactive(driver, vm);
> + if (ret < 0 && priv->nbdPort) {
> + virPortAllocatorRelease(driver->remotePorts, priv->nbdPort);
> + priv->nbdPort = 0;
> + }
> }
> if (event)
> qemuDomainEventQueue(driver, event);
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index 30f923a..2c57e0e 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -4240,6 +4240,11 @@ void qemuProcessStop(virQEMUDriverPtr driver,
> }
> }
>
> + if (priv->nbdPort) {
> + virPortAllocatorRelease(driver->remotePorts, priv->nbdPort);
> + priv->nbdPort = 0;
> + }
> +
> if (priv->agent) {
> qemuAgentClose(priv->agent);
> priv->agent = NULL;
>
--
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