releases/6.1.73/revert-nfsd-separate-nfsd_last_thread-from-nfsd_put.patch

   1 From c3cd2872f4aed958f70d7f871ea6cf3ff29d4674 Mon Sep 17 00:00:00 2001
   2 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   3 Date: Sat, 13 Jan 2024 10:38:35 +0100
   4 Subject: Revert "nfsd: separate nfsd_last_thread() from nfsd_put()"
   5
   6 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   7
   8 This reverts commit 03d68ffc48b94cc1e15bbf3b4f16f1e1e4fa286a which is
   9 commit 9f28a971ee9fdf1bf8ce8c88b103f483be610277 upstream.
  10
  11 It is reported to cause issues, so revert it.
  12
  13 Reported-by: email200202 <email200202@yahoo.com>
  14 Link: https://lore.kernel.org/r/e341cb408b5663d8c91b8fa57b41bb984be43448.camel@kernel.org
  15 Cc: NeilBrown <neilb@suse.de>
  16 Cc: Jeff Layton <jlayton@kernel.org>
  17 Cc: Chuck Lever <chuck.lever@oracle.com>
  18 Cc: Sasha Levin <sashal@kernel.org>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20 ---
  21  fs/nfsd/nfsd.h   |    7 +------
  22  fs/nfsd/nfssvc.c |   52 +++++++++++++++++++++++++++++++++-------------------
  23  2 files changed, 34 insertions(+), 25 deletions(-)
  24
  25 --- a/fs/nfsd/nfsd.h
  26 +++ b/fs/nfsd/nfsd.h
  27 @@ -97,12 +97,7 @@ int          nfsd_pool_stats_open(struct inode *
  28  int            nfsd_pool_stats_release(struct inode *, struct file *);
  29  void           nfsd_shutdown_threads(struct net *net);
  30
  31 -static inline void nfsd_put(struct net *net)
  32 -{
  33 -       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
  34 -
  35 -       svc_put(nn->nfsd_serv);
  36 -}
  37 +void           nfsd_put(struct net *net);
  38
  39  bool           i_am_nfsd(void);
  40
  41 --- a/fs/nfsd/nfssvc.c
  42 +++ b/fs/nfsd/nfssvc.c
  43 @@ -523,14 +523,9 @@ static struct notifier_block nfsd_inet6a
  44  /* Only used under nfsd_mutex, so this atomic may be overkill: */
  45  static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
  46
  47 -static void nfsd_last_thread(struct net *net)
  48 +static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
  49  {
  50         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
  51 -       struct svc_serv *serv = nn->nfsd_serv;
  52 -
  53 -       spin_lock(&nfsd_notifier_lock);
  54 -       nn->nfsd_serv = NULL;
  55 -       spin_unlock(&nfsd_notifier_lock);
  56
  57         /* check if the notifier still has clients */
  58         if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
  59 @@ -540,8 +535,6 @@ static void nfsd_last_thread(struct net
  60  #endif
  61         }
  62
  63 -       svc_xprt_destroy_all(serv, net);
  64 -
  65         /*
  66          * write_ports can create the server without actually starting
  67          * any threads--if we get shut down before any threads are
  68 @@ -632,8 +625,7 @@ void nfsd_shutdown_threads(struct net *n
  69         svc_get(serv);
  70         /* Kill outstanding nfsd threads */
  71         svc_set_num_threads(serv, NULL, 0);
  72 -       nfsd_last_thread(net);
  73 -       svc_put(serv);
  74 +       nfsd_put(net);
  75         mutex_unlock(&nfsd_mutex);
  76  }
  77
  78 @@ -663,6 +655,9 @@ int nfsd_create_serv(struct net *net)
  79         serv->sv_maxconn = nn->max_connections;
  80         error = svc_bind(serv, net);
  81         if (error < 0) {
  82 +               /* NOT nfsd_put() as notifiers (see below) haven't
  83 +                * been set up yet.
  84 +                */
  85                 svc_put(serv);
  86                 return error;
  87         }
  88 @@ -705,6 +700,29 @@ int nfsd_get_nrthreads(int n, int *nthre
  89         return 0;
  90  }
  91
  92 +/* This is the callback for kref_put() below.
  93 + * There is no code here as the first thing to be done is
  94 + * call svc_shutdown_net(), but we cannot get the 'net' from
  95 + * the kref.  So do all the work when kref_put returns true.
  96 + */
  97 +static void nfsd_noop(struct kref *ref)
  98 +{
  99 +}
 100 +
 101 +void nfsd_put(struct net *net)
 102 +{
 103 +       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 104 +
 105 +       if (kref_put(&nn->nfsd_serv->sv_refcnt, nfsd_noop)) {
 106 +               svc_xprt_destroy_all(nn->nfsd_serv, net);
 107 +               nfsd_last_thread(nn->nfsd_serv, net);
 108 +               svc_destroy(&nn->nfsd_serv->sv_refcnt);
 109 +               spin_lock(&nfsd_notifier_lock);
 110 +               nn->nfsd_serv = NULL;
 111 +               spin_unlock(&nfsd_notifier_lock);
 112 +       }
 113 +}
 114 +
 115  int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 116  {
 117         int i = 0;
 118 @@ -755,7 +773,7 @@ int nfsd_set_nrthreads(int n, int *nthre
 119                 if (err)
 120                         break;
 121         }
 122 -       svc_put(nn->nfsd_serv);
 123 +       nfsd_put(net);
 124         return err;
 125  }
 126
 127 @@ -770,7 +788,6 @@ nfsd_svc(int nrservs, struct net *net, c
 128         int     error;
 129         bool    nfsd_up_before;
 130         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 131 -       struct svc_serv *serv;
 132
 133         mutex_lock(&nfsd_mutex);
 134         dprintk("nfsd: creating service\n");
 135 @@ -790,25 +807,22 @@ nfsd_svc(int nrservs, struct net *net, c
 136                 goto out;
 137
 138         nfsd_up_before = nn->nfsd_net_up;
 139 -       serv = nn->nfsd_serv;
 140
 141         error = nfsd_startup_net(net, cred);
 142         if (error)
 143                 goto out_put;
 144 -       error = svc_set_num_threads(serv, NULL, nrservs);
 145 +       error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
 146         if (error)
 147                 goto out_shutdown;
 148 -       error = serv->sv_nrthreads;
 149 -       if (error == 0)
 150 -               nfsd_last_thread(net);
 151 +       error = nn->nfsd_serv->sv_nrthreads;
 152  out_shutdown:
 153         if (error < 0 && !nfsd_up_before)
 154                 nfsd_shutdown_net(net);
 155  out_put:
 156         /* Threads now hold service active */
 157         if (xchg(&nn->keep_active, 0))
 158 -               svc_put(serv);
 159 -       svc_put(serv);
 160 +               nfsd_put(net);
 161 +       nfsd_put(net);
 162  out:
 163         mutex_unlock(&nfsd_mutex);
 164         return error;