Revert "nfsd: separate nfsd_last_thread() from nfsd_put()"

This reverts commit 03d68ffc48b94cc1e15bbf3b4f16f1e1e4fa286a which is
commit 9f28a971ee9fdf1bf8ce8c88b103f483be610277 upstream.

It is reported to cause issues, so revert it.

Reported-by: email200202 <email200202@yahoo.com>
Link: https://lore.kernel.org/r/e341cb408b5663d8c91b8fa57b41bb984be43448.camel@kernel.org
Cc: NeilBrown <neilb@suse.de>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index fddd70372e4cbb47bf8351fc244e0b1bf92150c1..09726c5b9a317bbafe823c1c716e963d7a19f238 100644 (file)
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -97,12 +97,7 @@ 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);
 
-static inline void nfsd_put(struct net *net)
-{
-       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
-
-       svc_put(nn->nfsd_serv);
-}
+void           nfsd_put(struct net *net);
 
 bool           i_am_nfsd(void);
 

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index add0e2519c9a8f3abf7a249a81bb3549d5bf4dc7..c7695ebd28dc3c5b7934d988dc02a318fe599785 100644 (file)
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -523,14 +523,9 @@ 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 net *net)
+static void nfsd_last_thread(struct svc_serv *serv, 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) {
@@ -540,8 +535,6 @@ static void nfsd_last_thread(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
@@ -632,8 +625,7 @@ void nfsd_shutdown_threads(struct net *net)
        svc_get(serv);
        /* Kill outstanding nfsd threads */
        svc_set_num_threads(serv, NULL, 0);
-       nfsd_last_thread(net);
-       svc_put(serv);
+       nfsd_put(net);
        mutex_unlock(&nfsd_mutex);
 }
 
@@ -663,6 +655,9 @@ 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;
        }
@@ -705,6 +700,29 @@ 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;
@@ -755,7 +773,7 @@ int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
                if (err)
                        break;
        }
-       svc_put(nn->nfsd_serv);
+       nfsd_put(net);
        return err;
 }
 
@@ -770,7 +788,6 @@ 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");
@@ -790,25 +807,22 @@ 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(serv, NULL, nrservs);
+       error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
        if (error)
                goto out_shutdown;
-       error = serv->sv_nrthreads;
-       if (error == 0)
-               nfsd_last_thread(net);
+       error = nn->nfsd_serv->sv_nrthreads;
 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))
-               svc_put(serv);
-       svc_put(serv);
+               nfsd_put(net);
+       nfsd_put(net);
 out:
        mutex_unlock(&nfsd_mutex);
        return error;