NFSv4: Send RENEW requests to the server only when we're holding state

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/delegation.c

@@ -8,6 +8,7 @@
  */
 #include <linux/config.h>
 #include <linux/completion.h>
+#include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
@@ -231,6 +232,51 @@ void nfs_return_all_delegations(struct super_block *sb)
 	spin_unlock(&clp->cl_lock);
 }
 
+int nfs_do_expire_all_delegations(void *ptr)
+{
+	struct nfs4_client *clp = ptr;
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+	int err = 0;
+
+	allow_signal(SIGKILL);
+restart:
+	spin_lock(&clp->cl_lock);
+	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
+		goto out;
+	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
+		goto out;
+	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+		inode = igrab(delegation->inode);
+		if (inode == NULL)
+			continue;
+		spin_unlock(&clp->cl_lock);
+		err = nfs_inode_return_delegation(inode);
+		iput(inode);
+		if (!err)
+			goto restart;
+	}
+out:
+	spin_unlock(&clp->cl_lock);
+	nfs4_put_client(clp);
+	module_put_and_exit(0);
+}
+
+void nfs_expire_all_delegations(struct nfs4_client *clp)
+{
+	struct task_struct *task;
+
+	__module_get(THIS_MODULE);
+	atomic_inc(&clp->cl_count);
+	task = kthread_run(nfs_do_expire_all_delegations, clp,
+			"%u.%u.%u.%u-delegreturn",
+			NIPQUAD(clp->cl_addr));
+	if (!IS_ERR(task))
+		return;
+	nfs4_put_client(clp);
+	module_put(THIS_MODULE);
+}
+
 /*
  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
  */

fs/nfs/delegation.h

@@ -30,6 +30,7 @@ int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *s
 
 struct inode *nfs_delegation_find_inode(struct nfs4_client *clp, const struct nfs_fh *fhandle);
 void nfs_return_all_delegations(struct super_block *sb);
+void nfs_expire_all_delegations(struct nfs4_client *clp);
 void nfs_handle_cb_pathdown(struct nfs4_client *clp);
 
 void nfs_delegation_mark_reclaim(struct nfs4_client *clp);

fs/nfs/nfs4_fs.h

@@ -39,6 +39,7 @@ struct idmap;
 
 enum nfs4_client_state {
 	NFS4CLNT_STATE_RECOVER  = 0,
+	NFS4CLNT_LEASE_EXPIRED,
 };
 
 /*

fs/nfs/nfs4proc.c

@@ -63,6 +63,7 @@ static int nfs4_do_fsinfo(struct nfs_server *, struct nfs_fh *, struct nfs_fsinf
 static int nfs4_async_handle_error(struct rpc_task *, const struct nfs_server *);
 static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry);
 static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception);
+static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs4_client *clp);
 extern u32 *nfs4_decode_dirent(u32 *p, struct nfs_entry *entry, int plus);
 extern struct rpc_procinfo nfs4_procedures[];
 
@@ -765,6 +766,15 @@ static int _nfs4_do_access(struct inode *inode, struct rpc_cred *cred, int openf
 	return -EACCES;
 }
 
+int nfs4_recover_expired_lease(struct nfs_server *server)
+{
+	struct nfs4_client *clp = server->nfs4_state;
+
+	if (test_and_clear_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
+		nfs4_schedule_state_recovery(clp);
+	return nfs4_wait_clnt_recover(server->client, clp);
+}
+
 /*
  * OPEN_EXPIRED:
  * 	reclaim state on the server after a network partition.
@@ -840,6 +850,9 @@ static int _nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred
 	int open_flags = flags & (FMODE_READ|FMODE_WRITE);
 	int err;
 
+	err = nfs4_recover_expired_lease(server);
+	if (err != 0)
+		return err;
 	/* Protect against reboot recovery - NOTE ORDER! */
 	down_read(&clp->cl_sem);
 	/* Protect against delegation recall */
@@ -921,12 +934,16 @@ static int _nfs4_do_open(struct inode *dir, struct dentry *dentry, int flags, st
 	int                     status;
 
 	/* Protect against reboot recovery conflicts */
-	down_read(&clp->cl_sem);
 	status = -ENOMEM;
 	if (!(sp = nfs4_get_state_owner(server, cred))) {
 		dprintk("nfs4_do_open: nfs4_get_state_owner failed!\n");
 		goto out_err;
 	}
+	status = nfs4_recover_expired_lease(server);
+	if (status != 0)
+		goto out_err;
+	down_read(&clp->cl_sem);
+	status = -ENOMEM;
 	opendata = nfs4_opendata_alloc(dentry, sp, flags, sattr);
 	if (opendata == NULL)
 		goto err_put_state_owner;
@@ -2897,6 +2914,7 @@ nfs4_proc_setclientid_confirm(struct nfs4_client *clp)
 		spin_lock(&clp->cl_lock);
 		clp->cl_lease_time = fsinfo.lease_time * HZ;
 		clp->cl_last_renewal = now;
+		clear_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
 		spin_unlock(&clp->cl_lock);
 	}
 	return status;

fs/nfs/nfs4renewd.c

@@ -54,6 +54,7 @@
 #include <linux/nfs4.h>
 #include <linux/nfs_fs.h>
 #include "nfs4_fs.h"
+#include "delegation.h"
 
 #define NFSDBG_FACILITY	NFSDBG_PROC
 
@@ -68,7 +69,7 @@ nfs4_renew_state(void *data)
 	dprintk("%s: start\n", __FUNCTION__);
 	/* Are there any active superblocks? */
 	if (list_empty(&clp->cl_superblocks))
-		goto out; 
+		goto out;
 	spin_lock(&clp->cl_lock);
 	lease = clp->cl_lease_time;
 	last = clp->cl_last_renewal;
@@ -76,6 +77,12 @@ nfs4_renew_state(void *data)
 	timeout = (2 * lease) / 3 + (long)last - (long)now;
 	/* Are we close to a lease timeout? */
 	if (time_after(now, last + lease/3)) {
+		if (list_empty(&clp->cl_state_owners)) {
+			set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
+			spin_unlock(&clp->cl_lock);
+			nfs_expire_all_delegations(clp);
+			goto out;
+		}
 		spin_unlock(&clp->cl_lock);
 		/* Queue an asynchronous RENEW. */
 		nfs4_proc_async_renew(clp);