Recover Orphans from ObjectStore

The idea is to improve the management of objects from ObjectStorage and helps administrator to manage orphans that might appears on a de-sync between the table filecache and the objects stored on S3.

The development of this feature can be split in 3 steps:

first step:

• an occ command to list Orphans (by comparing the Objects available on the Storage and the one available in the table filecache),
• an occ command to delete Orphan by its ex-fileId.

second step:

• add metadata (filename, owner, ...) about the current local file for each entries of the ObjectStore,
• manage metadata on file creation, on file rename, on ownership transfer,
• an occ command to get metadata from the ObjectStore about a file, from its [ex-]fileId

third step:

• an occ command to recover an Orphan by creating a fresh entry in the table filecache
• an occ command to fill metadata of objects from the ObjectStore without metadata, based on local information from filecache

side note: the occ command to list Orphans should be able to also compare filesize and fix the data from the table filecache.

Start by mapping the three proposed steps across ObjectStorage, the filecache table, and occ command entry points, beginning with how stored objects are compared with filecache records. Done means the agreed scope covers orphan listing, deletion, metadata handling, recovery, and the proposed filesize comparison or repair behavior.