NFSv4: Iterate through all nfs_clients when the server recalls a delegation

The same delegation may have been handed out to more than one nfs_client.
Ensure that if a recall occurs, we return all instances.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/callback_proc.c

@@ -75,23 +75,28 @@ __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy)
 	dprintk("NFS: RECALL callback request from %s\n",
 		rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR));
 
+	do {
+		struct nfs_client *prev = clp;
+
 		inode = nfs_delegation_find_inode(clp, &args->fh);
-	if (inode == NULL)
-		goto out_putclient;
+		if (inode != NULL) {
 			/* Set up a helper thread to actually return the delegation */
 			switch(nfs_async_inode_return_delegation(inode, &args->stateid)) {
 				case 0:
 					res = 0;
 					break;
 				case -ENOENT:
+					if (res != 0)
 						res = htonl(NFS4ERR_BAD_STATEID);
 					break;
 				default:
 					res = htonl(NFS4ERR_RESOURCE);
 			}
 			iput(inode);
-out_putclient:
-	nfs_put_client(clp);
+		}
+		clp = nfs_find_client_next(prev);
+		nfs_put_client(prev);
+	} while (clp != NULL);
 out:
 	dprintk("%s: exit with status = %d\n", __FUNCTION__, ntohl(res));
 	return res;

fs/nfs/client.c

@@ -275,6 +275,41 @@ struct nfs_client *nfs_find_client(const struct sockaddr *addr, u32 nfsversion)
 	return NULL;
 }
 
+/*
+ * Find a client by IP address and protocol version
+ * - returns NULL if no such client
+ */
+struct nfs_client *nfs_find_client_next(struct nfs_client *clp)
+{
+	struct sockaddr *sap = (struct sockaddr *)&clp->cl_addr;
+	u32 nfsvers = clp->rpc_ops->version;
+
+	spin_lock(&nfs_client_lock);
+	list_for_each_entry_continue(clp, &nfs_client_list, cl_share_link) {
+		struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
+
+		/* Don't match clients that failed to initialise properly */
+		if (clp->cl_cons_state != NFS_CS_READY)
+			continue;
+
+		/* Different NFS versions cannot share the same nfs_client */
+		if (clp->rpc_ops->version != nfsvers)
+			continue;
+
+		if (sap->sa_family != clap->sa_family)
+			continue;
+		/* Match only the IP address, not the port number */
+		if (!nfs_sockaddr_match_ipaddr(sap, clap))
+			continue;
+
+		atomic_inc(&clp->cl_count);
+		spin_unlock(&nfs_client_lock);
+		return clp;
+	}
+	spin_unlock(&nfs_client_lock);
+	return NULL;
+}
+
 /*
  * Find an nfs_client on the list that matches the initialisation data
  * that is supplied.

fs/nfs/internal.h

@@ -64,6 +64,7 @@ extern struct rpc_program nfs_program;
 
 extern void nfs_put_client(struct nfs_client *);
 extern struct nfs_client *nfs_find_client(const struct sockaddr *, u32);
+extern struct nfs_client *nfs_find_client_next(struct nfs_client *);
 extern struct nfs_server *nfs_create_server(
 					const struct nfs_parsed_mount_data *,
 					struct nfs_fh *);