Matthew Oliver 6c62c8d072 Do not delete root_path on ContainerBroker.delete_db ...

When a shard is deleted all the sysmeta is deleted along with it. But
this is problematic as we support dealing with misplaced objects in
deleted shards. Which is required.

Currently, when we deal with misplaced objects in a shard broker
marked as deleted we push the objects into a handoff broker and set
this broker's root_path attribute from the deleted shard.
Unfortunately, root_path is itself stored in sysmeta, which has been
removed. So the deleted broker falls back to using its own account and
container in the root_path.  This in turn gets pushed to the shard
responsible for the misplaced objects and because these objects are
pushed by replication the root_path meta has a newer timestamp,
replacing the shard's pointer to the root.

As a consequence listings all still works because it's root driven,
but the shard will never pull the latest shard range details from the
_real_ root container during audits.

This patch contains a probe test that demonstrates this issue and also
fixes it by making 'X-Container-Sysmeta-Shard-Quoted-Root' and
'X-Container-Sysmeta-Shard-Root' whitelisted from being cleared on
delete. Meaning a deleted shard retains it's knowledge of root so it
can correctly deal with misplaced objects.

Co-Authored-By: Alistair Coles <alistairncoles@gmail.com>
Change-Id: I3315f349e5b965cecadc78af9e1c66c3f3bcfe83

2021-02-04 10:15:30 +00:00

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