Daniel Augusto Veronezi Salvador 7936eb04e9
server: Fix delete parent snapshot (#6630)
ACS + Xenserver works with differential snapshots. ACS takes a volume full snapshot and the next ones are referenced as a child of the previous snapshot until the chain reaches the limit defined in the global setting snapshot.delta.max; then, a new full snapshot is taken. PR #5297 introduced disk-only snapshots for KVM volumes. Among the changes, the delete process was also refactored. Before the changes, when one was removing a snapshot with children, ACS was marking it as Destroyed and it was keeping the Image entry on the table cloud.snapshot_store_ref as Ready. When ACS was rotating the snapshots (the max delta was reached) and all the children were already marked as removed; then, ACS would start removing the whole hierarchy, completing the differential snapshot cycle. After the changes, the snapshots with children stopped being marked as removed and the differential snapshot cycle was not being completed.

This PR intends to honor again the differential snapshot cycle for XenServer, making the snapshots to be marked as removed when deleted while having children and following the differential snapshot cycle.

Also, when one takes a volume snapshot and ACS backs it up to the secondary storage, ACS inserts 2 entries on table cloud.snapshot_store_ref (Primary and Image). When one deletes a volume snapshot, ACS first tries to remove the snapshot from the secondary storage and mark the entry Image as removed; then, it tries to remove the snapshot from the primary storage and mark the entry Primary as removed. If ACS cannot remove the snapshot from the primary storage, it will keep the snapshot as BackedUp; however, If it does not exist in the secondary storage and without the entry SNAPSHOT.DELETE on cloud.usage_event. In the end, after the garbage collector flow, the snapshot will be marked as BackedUp, with a value in the field removed and still being rated. This PR also addresses the correction for this situation.

Co-authored-by: GutoVeronezi <daniel@scclouds.com.br>
2022-10-13 12:31:11 +05:30
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