gcsf cache about gcsf

[harababurel]

It caches a few different things:

1. File list and metadata. This is populated at startup and then updated regularly depending on the value of sync_interval, as Google Drive reports remote changes which need to be applied locally
2. File contents. This is loaded and cached in RAM only when a file is read, such that subsequent reads are significantly faster. Can be controlled via cache_max_seconds and cache_max_items. Note that unmounting the filesystem clears the cache.
3. Filesystem size and capacity (values reported by df), controlled with cache_statfs_seconds.