Re: [libvirt] [PATCH v1 06/11] qemu_migration: Introduce qemuMigrationStartNBDServer

在 2012-11-27二的 19:50 +0100，Michal Privoznik写道： > This is a stub internal API just for now. Its purpose > in life is to start NBD server and feed it with all > domain disks. When adding a disk to NBD server, it > is addressed via its alias (id= param on qemu command line). > --- > src/qemu/qemu_driver.c | 8 +++--- > src/qemu/qemu_migration.c | 59 +++++++++++++++++++++++++++++++++++--------- > src/qemu/qemu_migration.h | 6 +++- > 3 files changed, 55 insertions(+), 18 deletions(-) >

> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c > index cd59eda..7e86c33 100644 > --- a/src/qemu/qemu_migration.c > +++ b/src/qemu/qemu_migration.c > @@ -1074,6 +1074,29 @@ error: > return NULL; > } > > +/** > + * qemuMigrationStartNBDServer: > + * @driver: qemu driver > + * @vm: domain > + * @nbdPort: which port is NBD server listening to > + * > + * 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(struct qemud_driver *driver ATTRIBUTE_UNUSED, > + virDomainObjPtr vm ATTRIBUTE_UNUSED, > + int *nbdPort ATTRIBUTE_UNUSED) > +{ > + /* do nothing for now */ > + return 0; > +} > + > + > /* 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 > @@ -1575,7 +1598,8 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, > const char *dname, > const char *dom_xml, > const char *migrateFrom, > - virStreamPtr st) > + virStreamPtr st, > + unsigned long flags) > { > virDomainDefPtr def = NULL; > virDomainObjPtr vm = NULL; > @@ -1719,9 +1743,17 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, > VIR_DEBUG("Received no lockstate"); > } > > - /* dummy place holder for real work */ > - nbdPort = 0; > - cookie_flags |= QEMU_MIGRATION_COOKIE_NBD; > + if ((flags & VIR_MIGRATE_NON_SHARED_INC || > + flags & VIR_MIGRATE_NON_SHARED_DISK) && > + mig->nbd && qemuCapsGet(priv->caps, QEMU_CAPS_NBD_SERVER)) { > + /* both source and destination qemus support nbd-server-* > + * commands and user requested disk copy. Use the new ones */ > + if (qemuMigrationStartNBDServer(driver, vm, &nbdPort) < 0) { so, nbdPort is generated by qemuMigrationNextPort() (08/11) not by cookie element 'nbd/port' (02/11), as a result, seems the previous cookie baking is rather needless.