Linux pnfs client rewrite may 2006

From Linux NFS

Revision as of 19:27, 3 May 2006

pNFS Client Rewrite May 2006

The main purpose of this rewrite is to separate the pNFS code path from the NFSv2/v3/v4 code path. Following the method used to separate the NFSv2/v3/v4 code paths from each other, I created a new rpc_ops for pNFS, and moved all pNFS processing into the appropriate routines. New rpc_ops were created where necessary. Existing nfs functions were split when necessary.

The rpc_ops are set at mount. The NFSv4 client uses the nfs_v4_clientops rpc_ops as usual. If a server supports pNFS and a layout driver has been negotiated and initalized, the nfs_v4_clientops are replaced with the new pnfs_v4_clientops (see set_pnfs_layoutderiver()). The pnfs_v4_clientops also contain a reference to the new pnfs_file_operations, and which are now set via the rpc_ops.

Four new rpc_ops allow pNFS to switch between using the normal server (server->rsize,rpages,wsize,wpages) read/write sizes and the data server read/write sizes (server->ds_rsize,ds_rpages,ds_wsize,ds_wpages) without if statements in the normal NFS code path.

   rsize(struct inode *, struct nfs_read_data *)
   wsize(struct inode *, struct nfs_write_data *)
   rpages(struct inode *, unsigned int *)
   wpages(struct inode *, unsigned int *)

Two new rpc_ops allow isolation of pNFS processing from normal NFS processing in the pageing setup for read and write.

   pagein_one(struct list_head *, struct inode *)

• pNFS client patches