* Add remote storage index for lazy metadata pull
Introduces remoteStorageIndex, which maintains a map of filer directory
to remote storage client/location, refreshed periodically from the
filer's mount mappings. Provides lazyFetchFromRemote, ensureRemoteEntryInFiler,
and isRemoteBacked on S3ApiServer as integration points for handler-level
work in a follow-up PR. Nothing is wired into the server yet.
Made-with: Cursor
* Add unit tests for remote storage index and wire field into S3ApiServer
Adds tests covering isEmpty, findForPath (including longest-prefix
resolution), and isRemoteBacked. Also removes a stray PR review
annotation from the index file and adds the remoteStorageIdx field
to S3ApiServer so the package compiles ahead of the wiring PR.
Made-with: Cursor
* Address review comments on remote storage index
- Use filer_pb.CreateEntry helper so resp.Error is checked, not just the RPC error
- Extract keepPrev closure to remove duplicated error-handling in refresh loop
- Add comment explaining availability-over-consistency trade-off on filer save failure
Made-with: Cursor
* Move lazy metadata pull from S3 API to filer
- Add maybeLazyFetchFromRemote in filer: on FindEntry miss, stat remote
and CreateEntry when path is under a remote mount
- Use singleflight for dedup; context guard prevents CreateEntry recursion
- Availability-over-consistency: return in-memory entry if CreateEntry fails
- Add longest-prefix test for nested mounts in remote_storage_test.go
- Remove remoteStorageIndex, lazyFetchFromRemote, ensureRemoteEntryInFiler,
doLazyFetch from s3api; filer now owns metadata operations
- Add filer_lazy_remote_test.go with tests for hit, miss, not-found,
CreateEntry failure, longest-prefix, and FindEntry integration
Made-with: Cursor
* Address review: fix context guard test, add FindMountDirectory comment, remove dead code
Made-with: Cursor
* Nitpicks: restore prev maker in registerStubMaker, instance-scope lazyFetchGroup, nil-check remoteEntry
Made-with: Cursor
* Fix remotePath when mountDir is root: ensure relPath has leading slash
Made-with: Cursor
* filer: decouple lazy-fetch persistence from caller context
Use context.Background() inside the singleflight closure for CreateEntry
so persistence is not cancelled when the winning request's context is
cancelled. Fixes CreateEntry failing for all waiters when the first
caller times out.
Made-with: Cursor
* filer: remove redundant Mode bitwise OR with zero
Made-with: Cursor
* filer: use bounded context for lazy-fetch persistence
Replace context.Background() with context.WithTimeout(30s) and defer
cancel() to prevent indefinite blocking and release resources.
Made-with: Cursor
* filer: use checked type assertion for singleflight result
Made-with: Cursor
* filer: rename persist context vars to avoid shadowing function parameter
Made-with: Cursor
