NFS: Add a dns resolver for use with NFSv4 referrals and migration

The NFSv4 and NFSv4.1 protocols both allow for the redirection of a client
from one server to another in order to support filesystem migration and
replication. For full protocol support, we need to add the ability to
convert a DNS host name into an IP address that we can feed to the RPC
client.

We'll reuse the sunrpc cache, now that it has been converted to work with
rpc_pipefs.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
2009-08-19 18:12:27 -04:00
parent 96c61cbd0f
commit e571cbf1a4
9 changed files with 639 additions and 1 deletions

27
fs/nfs/cache_lib.h Normal file
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/*
* Helper routines for the NFS client caches
*
* Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
*/
#include <linux/completion.h>
#include <linux/sunrpc/cache.h>
#include <asm/atomic.h>
/*
* Deferred request handling
*/
struct nfs_cache_defer_req {
struct cache_req req;
struct cache_deferred_req deferred_req;
struct completion completion;
atomic_t count;
};
extern int nfs_cache_upcall(struct cache_detail *cd, char *entry_name);
extern struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void);
extern void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq);
extern int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq);
extern int nfs_cache_register(struct cache_detail *cd);
extern void nfs_cache_unregister(struct cache_detail *cd);