On Mon, 21 Sep 2015 07:54:55 PM Peter Ross wrote:
I would like to export parts of the server file systems but do not need to share them between the clients. So I don't need all the overhead of leases that expire, server-side locking etc.
Instead it would be good enough to do locking on the client side and write a journal which can be send to the file server.
Isn't this basically NFSv4 delegations? If you're exporting it to just a single client then I'd expect no other client can interfere with them. https://www.ietf.org/rfc/rfc3530.txt 1.4.6. Client Caching and Delegation [...] The major addition to NFS version 4 in the area of caching is the ability of the server to delegate certain responsibilities to the client. When the server grants a delegation for a file to a client, the client is guaranteed certain semantics with respect to the sharing of that file with other clients. At OPEN, the server may provide the client either a read or write delegation for the file. If the client is granted a read delegation, it is assured that no other client has the ability to write to the file for the duration of the delegation. If the client is granted a write delegation, the client is assured that no other client has read or write access to the file. Delegations can be recalled by the server. If another client requests access to the file in such a way that the access conflicts with the granted delegation, the server is able to notify the initial client and recall the delegation. This requires that a callback path exist between the server and client. If this callback path does not exist, then delegations can not be granted. The essence of a delegation is that it allows the client to locally service operations such as OPEN, CLOSE, LOCK, LOCKU, READ, WRITE without immediate interaction with the server. -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC