On 02/07/2018 12:05 PM, Daniel P. Berrangé wrote:
On Wed, Feb 07, 2018 at 11:57:19AM -0600, Chris Friesen wrote:
In the current implementation of qemuMigrateDisk() the value of the "nmigrate_disks" parameter wrongly impacts the decision whether or not to migrate a disk that is not a member of "migrate_disks":
1) If "nmigrate_disks" is zero, "disk" is migrated if it's non-shared non-readonly with source.
2) If "nmigrate_disks" is non-zero and "disk" is not a member of "migrate_disks" then "disk" is not migrated. This should instead proceed with checking conditions as per 1) and allow migration of non-shared non-readonly disks with source.
Huh, this doesn't make sense. If an app has passed a list of disks in migrate_disks, we must *never* touch any disk that is not present in this list. If the app wanted the other disk(s) migrated, it would have included it in the list of disks it passed in.
Okay, that makes sense. I can restore the "return false" here. Are you okay with the other change? Our original problem scenario was where the root disk is rbd and there is a read-only ISO config-drive, and "nmigrate_disks" is zero. What we see in this case is that qemuMigrateDisk() returns "true" for the rbd disk, which then causes qemuMigrationPrecreateStorage() to fail with "pre-creation of storage targets for incremental storage migration is not supported". Chris