From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Sat, 26 Jan 2008 01:06:40 -0500
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 |   39 ++++++++++++++++++++++-----------------
 fs/nfs/client.c        |   35 +++++++++++++++++++++++++++++++++++
 fs/nfs/internal.h      |    1 +
 3 files changed, 58 insertions(+), 17 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index e89a900..15f7785 100644
--- a/fs/nfs/callback_proc.c
+++ b/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));
 
-	inode = nfs_delegation_find_inode(clp, &args->fh);
-	if (inode == NULL)
-		goto out_putclient;
-	/* 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:
-			res = htonl(NFS4ERR_BAD_STATEID);
-			break;
-		default:
-			res = htonl(NFS4ERR_RESOURCE);
-	}
-	iput(inode);
-out_putclient:
-	nfs_put_client(clp);
+	do {
+		struct nfs_client *prev = clp;
+
+		inode = nfs_delegation_find_inode(clp, &args->fh);
+		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);
+		}
+		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;
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 7a15832..685c43f 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -276,6 +276,41 @@ struct nfs_client *nfs_find_client(const struct sockaddr *addr, u32 nfsversion)
 }
 
 /*
+ * 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.
  */
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index a806211..0f56196 100644
--- a/fs/nfs/internal.h
+++ b/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 *);