The S3 extension filesystem configuration creates a local directory to cache the objects. Either it is provided by the user or defaults to bucket-cache. The extension configuration also takes a prefix, which is prepended to all the objects that are created. The object created is also linked as a file into the local cache.

S3 can take prefixes that simulate directory structure. eg: A prefix of "sub_bucketA/pfx_". When such a prefix is used for caching the files, the file name reflects the directory structure implied by the prefix: bucket-cache/sub_bucketA/pfx_. The linking into the cache directory fails, because the intermediate directory structure was not created, ../sub_bucketA/...

This ticket will address this problem, and add relevant testing.