PNFS Todo List

From Linux NFS

Revision as of 02:50, 28 February 2009

NFSv4.1 (sessions) Todo List

Client

• [2009-02] mount version negotiation
  • Propagate error up to the mount system call (Andy)
  • Update mount utils command to reissue the mount with a different version (SteveD)
• [2009-02] New backchannel implementation that handles multiple flavor authentication (Ricardo)
• [2009-02] Documentation
  • What functionality is supported? What will a user be able to do?
• [2009-02] Lock Sequencing
  • With the advent of Sessions, the open sequencing should be reworked to avoid double sequencing. No need to sequence in the operations if the session is already sequencing (Lower priority)
• [2008-08] Propose design for unified client/LD device cache. (Benny)

Server

• Bug 172 - EXCHANGE_ID does not reply on first request (Andy)
• [2009-02] Client should validate Backchannel attributes
  • The client determines the resources used by the backchannel. If the server ignores the client specification, and changes the values, the client shou8ld drop the mount to v4
• Bruce wants a patch for the Documentation directory that explains which features we have implemented and which we have not.
  • He wants this done from a user's perspective - what would a fully functional NFSv4.1 sessions client see from the server?
  • Document the ramifications of the present implementation
    • shortcuts we made.
    • Document server owner implementation.
• [2008-10] Never return NFS4ERR_RESOURCE in nfs41/pnfs. Error code was deprecated. Typically need to return NFS4ERR_REQ_TOO_BIG instead.
• [2008-04-10] Add an option to control nfsv4.1 on the server side.
  • The motivation is disabling 4.1 on the server without having to rebuild the kernel. Some use cases: a faulty 4.1 client, or one that's crashing the server, or just for easier debugging of the client (4.1 client mounting a 4.0 server).

Ann Arbor 11/08 Review Patches

The following still need to be addressed:

• [11/51] nfsd41-sessions-basic-data-types.patch we'll need at least one per-session max. variable maybe a global max.
  • nfsd_compoundargs has a max size for the preallocated ops array. need to define that in a header file use for both nfs4 and nfs41. (preallocated per nfsd thread)
  • review storing negotiated back channel session parameters
• [23] nfsd41-xdr-stubs.patch
  • review 11-13: add comment about why we don't need nfsd4_enc_ops per minorversion like we do for the decoding vector.
• 0030-nfsd41-destroy_session-operation.patch
  • > + shutdown_callback_client(ses->se_client);
  • review 11-12: we need ref. counting for that backchannel to support trunking.
  • clp->cl_callback.cb_client is shared?
• Write a commit message for [PATCH 36/46] nfsd41: sunrpc: Added rpc server-side backchannel handling
  • FIXME: bhalevy: write up commit message
• Need to discuss multiple per client session fore and back channel support.
• Ensure the server passes all of the pynfs4.1 testserver.py tests.
  • A bit of work here.
• Ensure the server passes all of the pynfs4.0 testserver.py tests that the unpatched server pases over a v4.0 mount when CONFIG_NFSD_V4_1 is configured, and when it is not.
  • A bit of work here.

pNFS Todo List

• [2008-10] Properly define NFS4_DEV_NOTIFY_MAXENTRIES to handle anything that fits in the negotiated max. request size for the backchannel.

• [2008-06-30] Separate pnfsd export and callback API out of export_operations. (Ricardo)

• [2008-06-30] Clean up pnfsd callback vector registration model. Provide for orderly nfsd shutdown to allow the filesystem to recall layouts upon shutdown.

• [2008-04-02] Implement pnfs-aware page sync state model.

proposed model

• Bug 173 - Need to retry EXCHANGE_ID and CREATE_SESSION to Data Server

Done

• [2008-08] Revamp reply cache for nfsv4 and nfsv4.1. (Andy)

• [2008-08] Trond verbally NACKed rpc_call_validate_args, suggest looking into using existing rpc_call_prepare infrastructure instead. (Andy)

• [2008-06-30] Change fs/nfsd/nfs4xdr.c decoding/encoding to table based (bhalevy)

• [2008-04-07] Prepare and send nfs41 patches for review. (bhalevy)
  • Depends on support for concurrent 4.0 and 4.1 mounts.

• [2008-04-07] Add an option for nfsv4.1 to the nfs mount program.
  • "{nfs,}vers=41" seems to be the most appropriate. See nfs_mount_option_tokens in fs/nfs/super.c. Note that kernel nfs root (in fs/nfs/nfsroot.c does not current (2.6.25-rc8) support root over nfsv4 only "nfsvers=[23]".

• [2008-04-07] Support concurrent nfsv4.0 and 4.1.
  • Get rid of global nfs4_procedures and move the pointer to struct nfs_client. (bhalevy)
  • nfs_version4 should not be global. We apparently need to either:
    • Split nfs_version and nfs_program to nfs_{version,program}4 and nfs_{version,program}41, make them static in fs/nfs/client.c and use either based on minorversion, or
    • teach rpc code, e.g. rpc_bind_new_program about minor version (and represent it in struct rpc_version). (bhalevy)
  • Manage callback threads for 4.0 and 4.1
    • Can either keep a separate use count, or
    • bring them up and down together. (rlabiaga)

• Agree on LD API changes for block layout (Fred and Dean) then merge generic pnfs patch (fred-pnfs) into pnfs branch. (bhalevy)

• [2008-04-02] Implement layout stateid as per draft-21+ (andros)