[Samba] Am I nuts to attempt a VFS local cache module?

[Mark Winslow]

Sorry if this isn't the right place to ask this question.

I'm thinking of writing a module that intercepts Samba requests to keep 
only a subset of a file store on a local server with the rest being 
stored on a cloud.  It would be an open source module similar to these 
products:

https://aws.amazon.com/storagegateway/

https://docs.microsoft.com/en-us/azure/storage/files/storage-sync-files-deployment-guide?tabs=azure-portal

I'm thinking that I would have to do the following.

1. Keep my own directory lists, probably in Mongodb
2. Intercept File Open,Dir,and Stat requests from Samba
3. When a request to open is received for a file that doesn't exist 
locally, create a thread to retrieve the file from the cloud, blocking 
the request until the file is retrieved.
4. Have a background process that archives files to the cloud when necessary
5. Have a background process that retrieves files from the cloud when 
the local store needs to be rebuilt.

If Samba does any file access operations outside of interceptable VFS 
requests, then I guess I'm out of luck.

The reasons I'm interested in doing this are:

1. Won't have to incessantly worry about disk size on  servers
2. Can rebuild servers seemlessly from cloud when local server is 
compromised.

Is this idea wrong?  Has it already been done?  Is there a better 
alternative?

Thanks,

Mark