NFS: use scope from exchange_id to skip reclaim

can be skipped if the "eir_server_scope" from the exchange_id proc differs from
previous calls.

Also, in the future server_scope will be useful for determining whether client
trunking is available

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 5879b23e0c99..5f4912f72282 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4781,6 +4781,16 @@ out_inval:
         return -NFS4ERR_INVAL;
 }
 
+static bool
+nfs41_same_server_scope(struct server_scope *a, struct server_scope *b)
+{
+        if (a->server_scope_sz == b->server_scope_sz &&
+            memcmp(a->server_scope, b->server_scope, a->server_scope_sz) == 0)
+                return true;
+
+        return false;
+}
+
 /*
  * nfs4_proc_exchange_id()
  *
@@ -4823,9 +4833,31 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
                                 init_utsname()->domainname,
                                 clp->cl_rpcclient->cl_auth->au_flavor);
 
+        res.server_scope = kzalloc(sizeof(struct server_scope), GFP_KERNEL);
+        if (unlikely(!res.server_scope))
+                return -ENOMEM;
+
         status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
         if (!status)
                 status = nfs4_check_cl_exchange_flags(clp->cl_exchange_flags);
+
+        if (!status) {
+                if (clp->server_scope &&
+                    !nfs41_same_server_scope(clp->server_scope,
+                                             res.server_scope)) {
+                        dprintk("%s: server_scope mismatch detected\n",
+                                __func__);
+                        set_bit(NFS4CLNT_SERVER_SCOPE_MISMATCH, &clp->cl_state);
+                        kfree(clp->server_scope);
+                        clp->server_scope = NULL;
+                }
+
+                if (!clp->server_scope)
+                        clp->server_scope = res.server_scope;
+                else
+                        kfree(res.server_scope);
+        }
+
         dprintk("<-- %s status= %d\n", __func__, status);
         return status;
 }