Fixes two problems
- Double healing when bitrot is enabled, instead heal attempt
once in applyActions() before lifecycle is applied.
- If applyActions() is successful and getSize() returns proper
value, then object is accounted for and should be removed
from the oldCache namespace map to avoid double heal attempts.
Do listings with prefix filter when bloom filter is dirty.
This will forward the prefix filter to the lister which will make it
only scan the folders/objects with the specified prefix.
If we have a clean bloom filter we try to build a more generally
useful cache so in that case, we will list all objects/folders.
Add shortcut for `APN/1.0 Veeam/1.0 Backup/10.0`
It requests unique blocks with a specific prefix. We skip
scanning the parent directory for more objects matching the prefix.
Design: https://gist.github.com/klauspost/025c09b48ed4a1293c917cecfabdf21c
Gist of improvements:
* Cross-server caching and listing will use the same data across servers and requests.
* Lists can be arbitrarily resumed at a constant speed.
* Metadata for all files scanned is stored for streaming retrieval.
* The existing bloom filters controlled by the crawler is used for validating caches.
* Concurrent requests for the same data (or parts of it) will not spawn additional walkers.
* Listing a subdirectory of an existing recursive cache will use the cache.
* All listing operations are fully streamable so the number of objects in a bucket no
longer dictates the amount of memory.
* Listings can be handled by any server within the cluster.
* Caches are cleaned up when out of date or superseded by a more recent one.
