Commit f15e1e8b authored by NeilBrown's avatar NeilBrown Committed by Anna Schumaker
Browse files

NFSv4: don't require lock for get_renew_cred or get_machine_cred 



This lock is no longer necessary.

If nfs4_get_renew_cred() needs to hunt through the open-state
creds for a user cred, it still takes the lock to stablize
the rbtree, but otherwise there are no races.

Note that this completely removes the lock from nfs4_renew_state().
It appears that the original need for the locking here was removed
long ago, and there is no longer anything to protect.

Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent a534ecb0

fs/nfs/nfs4_fs.h

+3 −3
Original line number Diff line number Diff line
@@ -250,7 +250,7 @@ struct nfs4_add_xprt_data { 


struct nfs4_state_maintenance_ops {

	int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *, unsigned);

	struct rpc_cred * (*get_state_renewal_cred_locked)(struct nfs_client *);

	struct rpc_cred * (*get_state_renewal_cred)(struct nfs_client *);

	int (*renew_lease)(struct nfs_client *, struct rpc_cred *);

};
@@ -451,8 +451,8 @@ extern void nfs4_set_lease_period(struct nfs_client *clp, 


/* nfs4state.c */

struct rpc_cred *nfs4_get_clid_cred(struct nfs_client *clp);

struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp);

struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp);

struct rpc_cred *nfs4_get_machine_cred(struct nfs_client *clp);

struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp);

int nfs4_discover_server_trunking(struct nfs_client *clp,

			struct nfs_client **);

int nfs40_discover_server_trunking(struct nfs_client *clp,

fs/nfs/nfs4proc.c

+2 −2
Original line number Diff line number Diff line
@@ -9606,14 +9606,14 @@ static const struct nfs4_state_recovery_ops nfs41_nograce_recovery_ops = { 


static const struct nfs4_state_maintenance_ops nfs40_state_renewal_ops = {

	.sched_state_renewal = nfs4_proc_async_renew,

	.get_state_renewal_cred_locked = nfs4_get_renew_cred_locked,

	.get_state_renewal_cred = nfs4_get_renew_cred,

	.renew_lease = nfs4_proc_renew,

};



#if defined(CONFIG_NFS_V4_1)

static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = {

	.sched_state_renewal = nfs41_proc_async_sequence,

	.get_state_renewal_cred_locked = nfs4_get_machine_cred_locked,

	.get_state_renewal_cred = nfs4_get_machine_cred,

	.renew_lease = nfs4_proc_sequence,

};

#endif

fs/nfs/nfs4renewd.c

+1 −4
Original line number Diff line number Diff line
@@ -68,7 +68,6 @@ nfs4_renew_state(struct work_struct *work) 
	if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))

		goto out;



	spin_lock(&clp->cl_lock);

	lease = clp->cl_lease_time;

	last = clp->cl_last_renewal;

	now = jiffies;
@@ -79,8 +78,7 @@ nfs4_renew_state(struct work_struct *work) 
		renew_flags |= NFS4_RENEW_DELEGATION_CB;



	if (renew_flags != 0) {

		cred = ops->get_state_renewal_cred_locked(clp);

		spin_unlock(&clp->cl_lock);

		cred = ops->get_state_renewal_cred(clp);

		if (cred == NULL) {

			if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {

				set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
@@ -104,7 +102,6 @@ nfs4_renew_state(struct work_struct *work) 
	} else {

		dprintk("%s: failed to call renewd. Reason: lease not expired \n",

				__func__);

		spin_unlock(&clp->cl_lock);

	}

	nfs4_schedule_state_renewal(clp);

out_exp:

fs/nfs/nfs4state.c

+10 −16
Original line number Diff line number Diff line
@@ -164,7 +164,7 @@ out: 
	return status;

}



struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp)

struct rpc_cred *nfs4_get_machine_cred(struct nfs_client *clp)

{

	struct rpc_cred *cred = clp->cl_root_cred;
@@ -210,22 +210,23 @@ nfs4_get_renew_cred_server_locked(struct nfs_server *server) 
}



/**

 * nfs4_get_renew_cred_locked - Acquire credential for a renew operation

 * nfs4_get_renew_cred - Acquire credential for a renew operation

 * @clp: client state handle

 *

 * Returns an rpc_cred with reference count bumped, or NULL.

 * Caller must hold clp->cl_lock.

 */

struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp)

struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp)

{

	struct rpc_cred *cred = NULL;

	struct nfs_server *server;



	/* Use machine credentials if available */

	cred = nfs4_get_machine_cred_locked(clp);

	cred = nfs4_get_machine_cred(clp);

	if (cred != NULL)

		goto out;



	spin_lock(&clp->cl_lock);

	rcu_read_lock();

	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {

		cred = nfs4_get_renew_cred_server_locked(server);
@@ -233,6 +234,7 @@ struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp) 
			break;

	}

	rcu_read_unlock();

	spin_unlock(&clp->cl_lock);



out:

	return cred;
@@ -402,9 +404,7 @@ struct rpc_cred *nfs4_get_clid_cred(struct nfs_client *clp) 
{

	struct rpc_cred *cred;



	spin_lock(&clp->cl_lock);

	cred = nfs4_get_machine_cred_locked(clp);

	spin_unlock(&clp->cl_lock);

	cred = nfs4_get_machine_cred(clp);

	return cred;

}
@@ -1908,9 +1908,7 @@ static int nfs4_check_lease(struct nfs_client *clp) 
	/* Is the client already known to have an expired lease? */

	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))

		return 0;

	spin_lock(&clp->cl_lock);

	cred = ops->get_state_renewal_cred_locked(clp);

	spin_unlock(&clp->cl_lock);

	cred = ops->get_state_renewal_cred(clp);

	if (cred == NULL) {

		cred = nfs4_get_clid_cred(clp);

		status = -ENOKEY;
@@ -2112,9 +2110,7 @@ static int nfs4_handle_migration(struct nfs_client *clp) 
	dprintk("%s: migration reported on \"%s\"\n", __func__,

			clp->cl_hostname);



	spin_lock(&clp->cl_lock);

	cred = ops->get_state_renewal_cred_locked(clp);

	spin_unlock(&clp->cl_lock);

	cred = ops->get_state_renewal_cred(clp);

	if (cred == NULL)

		return -NFS4ERR_NOENT;
@@ -2160,9 +2156,7 @@ static int nfs4_handle_lease_moved(struct nfs_client *clp) 
	dprintk("%s: lease moved reported on \"%s\"\n", __func__,

			clp->cl_hostname);



	spin_lock(&clp->cl_lock);

	cred = ops->get_state_renewal_cred_locked(clp);

	spin_unlock(&clp->cl_lock);

	cred = ops->get_state_renewal_cred(clp);

	if (cred == NULL)

		return -NFS4ERR_NOENT;

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