Commit 9f28a971 authored by NeilBrown's avatar NeilBrown Committed by Chuck Lever
Browse files

nfsd: separate nfsd_last_thread() from nfsd_put() 



Now that the last nfsd thread is stopped by an explicit act of calling
svc_set_num_threads() with a count of zero, we only have a limited
number of places that can happen, and don't need to call
nfsd_last_thread() in nfsd_put()

So separate that out and call it at the two places where the number of
threads is set to zero.

Move the clearing of ->nfsd_serv and the call to svc_xprt_destroy_all()
into nfsd_last_thread(), as they are really part of the same action.

nfsd_put() is now a thin wrapper around svc_put(), so make it a static
inline.

nfsd_put() cannot be called after nfsd_last_thread(), so in a couple of
places we have to use svc_put() instead.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 18e4cf91

fs/nfsd/nfsd.h

+6 −1
Original line number Diff line number Diff line
@@ -96,7 +96,12 @@ int nfsd_pool_stats_open(struct inode *, struct file *); 
int		nfsd_pool_stats_release(struct inode *, struct file *);

void		nfsd_shutdown_threads(struct net *net);



void		nfsd_put(struct net *net);

static inline void nfsd_put(struct net *net)

{

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);



	svc_put(nn->nfsd_serv);

}



bool		i_am_nfsd(void);

fs/nfsd/nfssvc.c

+19 −33
Original line number Diff line number Diff line
@@ -542,9 +542,14 @@ static struct notifier_block nfsd_inet6addr_notifier = { 
/* Only used under nfsd_mutex, so this atomic may be overkill: */

static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);



static void nfsd_last_thread(struct svc_serv *serv, struct net *net)

static void nfsd_last_thread(struct net *net)

{

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	struct svc_serv *serv = nn->nfsd_serv;



	spin_lock(&nfsd_notifier_lock);

	nn->nfsd_serv = NULL;

	spin_unlock(&nfsd_notifier_lock);



	/* check if the notifier still has clients */

	if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
@@ -554,6 +559,8 @@ static void nfsd_last_thread(struct svc_serv *serv, struct net *net) 
#endif

	}



	svc_xprt_destroy_all(serv, net);



	/*

	 * write_ports can create the server without actually starting

	 * any threads--if we get shut down before any threads are
@@ -644,7 +651,8 @@ void nfsd_shutdown_threads(struct net *net) 
	svc_get(serv);

	/* Kill outstanding nfsd threads */

	svc_set_num_threads(serv, NULL, 0);

	nfsd_put(net);

	nfsd_last_thread(net);

	svc_put(serv);

	mutex_unlock(&nfsd_mutex);

}
@@ -674,9 +682,6 @@ int nfsd_create_serv(struct net *net) 
	serv->sv_maxconn = nn->max_connections;

	error = svc_bind(serv, net);

	if (error < 0) {

		/* NOT nfsd_put() as notifiers (see below) haven't

		 * been set up yet.

		 */

		svc_put(serv);

		return error;

	}
@@ -719,29 +724,6 @@ int nfsd_get_nrthreads(int n, int *nthreads, struct net *net) 
	return 0;

}



/* This is the callback for kref_put() below.

 * There is no code here as the first thing to be done is

 * call svc_shutdown_net(), but we cannot get the 'net' from

 * the kref.  So do all the work when kref_put returns true.

 */

static void nfsd_noop(struct kref *ref)

{

}



void nfsd_put(struct net *net)

{

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);



	if (kref_put(&nn->nfsd_serv->sv_refcnt, nfsd_noop)) {

		svc_xprt_destroy_all(nn->nfsd_serv, net);

		nfsd_last_thread(nn->nfsd_serv, net);

		svc_destroy(&nn->nfsd_serv->sv_refcnt);

		spin_lock(&nfsd_notifier_lock);

		nn->nfsd_serv = NULL;

		spin_unlock(&nfsd_notifier_lock);

	}

}



int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)

{

	int i = 0;
@@ -792,7 +774,7 @@ int nfsd_set_nrthreads(int n, int *nthreads, struct net *net) 
		if (err)

			break;

	}

	nfsd_put(net);

	svc_put(nn->nfsd_serv);

	return err;

}
@@ -807,6 +789,7 @@ nfsd_svc(int nrservs, struct net *net, const struct cred *cred) 
	int	error;

	bool	nfsd_up_before;

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	struct svc_serv *serv;



	mutex_lock(&nfsd_mutex);

	dprintk("nfsd: creating service\n");
@@ -826,22 +809,25 @@ nfsd_svc(int nrservs, struct net *net, const struct cred *cred) 
		goto out;



	nfsd_up_before = nn->nfsd_net_up;

	serv = nn->nfsd_serv;



	error = nfsd_startup_net(net, cred);

	if (error)

		goto out_put;

	error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);

	error = svc_set_num_threads(serv, NULL, nrservs);

	if (error)

		goto out_shutdown;

	error = nn->nfsd_serv->sv_nrthreads;

	error = serv->sv_nrthreads;

	if (error == 0)

		nfsd_last_thread(net);

out_shutdown:

	if (error < 0 && !nfsd_up_before)

		nfsd_shutdown_net(net);

out_put:

	/* Threads now hold service active */

	if (xchg(&nn->keep_active, 0))

		nfsd_put(net);

	nfsd_put(net);

		svc_put(serv);

	svc_put(serv);

out:

	mutex_unlock(&nfsd_mutex);

	return error;