* master: re-create a vacuum-committed volume the index has lost
SetVolumeAvailable dereferenced vid2location[vid] with no nil check. A
disconnect during a long vacuum can drop a single-replica volume from the
lookup index while it stays on the node; the commit then panics the master
instead of re-registering it. Re-create the entry, and seed its size tracking
so assigns are counted right away rather than after the next heartbeat.
* master: re-register a vacuumed volume the index lost on mark-writable
The maintenance worker re-enables a volume by marking it writable after the
vacuum commit, but VolumeMarkReadonly only updated nodes the lookup index
already knew. If a disconnect race dropped the volume from the index during the
vacuum, that path was a no-op and the volume stayed "not found" until the next
full heartbeat healed it. Re-register it from the node that still holds it.
Chris Lu
a6effe3cfb