4 files changed, 40 insertions, 15 deletions

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index bce744468708..52774feab93f 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -147,11 +147,10 @@ u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
  * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number,
  * that we mark locks for reclaiming, and that we bump the pseudo NSM state.
  */
-static inline
-void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate)
+static void nlmclnt_prepare_reclaim(struct nlm_host *host)
 {
+        down_write(&host->h_rwsem);
         host->h_monitored = 0;
-        host->h_nsmstate = newstate;
         host->h_state++;
         host->h_nextrebind = 0;
         nlm_rebind_host(host);
@@ -164,6 +163,13 @@ void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate)
         dprintk("NLM: reclaiming locks for host %s", host->h_name);
 }
 
+static void nlmclnt_finish_reclaim(struct nlm_host *host)
+{
+        host->h_reclaiming = 0;
+        up_write(&host->h_rwsem);
+        dprintk("NLM: done reclaiming locks for host %s", host->h_name);
+}
+
 /*
  * Reclaim all locks on server host. We do this by spawning a separate
  * reclaimer thread.
@@ -171,12 +177,10 @@ void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate)
 void
 nlmclnt_recovery(struct nlm_host *host, u32 newstate)
 {
-        if (host->h_reclaiming++) {
-                if (host->h_nsmstate == newstate)
-                        return;
-                nlmclnt_prepare_reclaim(host, newstate);
-        } else {
-                nlmclnt_prepare_reclaim(host, newstate);
+        if (host->h_nsmstate == newstate)
+                return;
+        host->h_nsmstate = newstate;
+        if (!host->h_reclaiming++) {
                 nlm_get_host(host);
                 __module_get(THIS_MODULE);
                 if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
@@ -190,6 +194,7 @@ reclaimer(void *ptr)
         struct nlm_host   *host = (struct nlm_host *) ptr;
         struct nlm_wait   *block;
         struct file_lock *fl, *next;
+        u32 nsmstate;
 
         daemonize("%s-reclaim", host->h_name);
         allow_signal(SIGKILL);
@@ -199,19 +204,25 @@ reclaimer(void *ptr)
         lock_kernel();
         lockd_up();
 
+        nlmclnt_prepare_reclaim(host);
         /* First, reclaim all locks that have been marked. */
 restart:
+        nsmstate = host->h_nsmstate;
         list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
                 list_del_init(&fl->fl_u.nfs_fl.list);
 
                 if (signalled())
                         continue;
-                if (nlmclnt_reclaim(host, fl) == 0)
-                        list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
-                goto restart;
+                if (nlmclnt_reclaim(host, fl) != 0)
+                        continue;
+                list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
+                if (host->h_nsmstate != nsmstate) {
+                        /* Argh! The server rebooted again! */
+                        list_splice_init(&host->h_granted, &host->h_reclaim);
+                        goto restart;
+                }
         }
-
-        host->h_reclaiming = 0;
+        nlmclnt_finish_reclaim(host);
 
         /* Now, wake up all processes that sleep on a blocked lock */
         list_for_each_entry(block, &nlm_blocked, b_list) {
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index f96e38155b5c..4db62098d3f4 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -508,7 +508,10 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
         }
 
         block = nlmclnt_prepare_block(host, fl);
+again:
         for(;;) {
+                /* Reboot protection */
+                fl->fl_u.nfs_fl.state = host->h_state;
                 status = nlmclnt_call(req, NLMPROC_LOCK);
                 if (status < 0)
                         goto out_unblock;
@@ -531,10 +534,16 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
         }
 
         if (resp->status == NLM_LCK_GRANTED) {
-                fl->fl_u.nfs_fl.state = host->h_state;
+                down_read(&host->h_rwsem);
+                /* Check whether or not the server has rebooted */
+                if (fl->fl_u.nfs_fl.state != host->h_state) {
+                        up_read(&host->h_rwsem);
+                        goto again;
+                }
                 fl->fl_flags |= FL_SLEEP;
                 /* Ensure the resulting lock will get added to granted list */
                 do_vfs_lock(fl);
+                up_read(&host->h_rwsem);
         }
         status = nlm_stat_to_errno(resp->status);
 out_unblock:
@@ -596,6 +605,7 @@ nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 static int
 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 {
+        struct nlm_host *host = req->a_host;
         struct nlm_res  *resp = &req->a_res;
         int             status;
 
@@ -604,7 +614,9 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
          * case, we want to unlock.
          */
+        down_read(&host->h_rwsem);
         do_vfs_lock(fl);
+        up_read(&host->h_rwsem);
 
         if (req->a_flags & RPC_TASK_ASYNC)
                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index 5242743c9403..38b0e8a1aec0 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -117,6 +117,7 @@ nlm_lookup_host(int server, struct sockaddr_in *sin,
         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
         atomic_set(&host->h_count, 1);
         init_waitqueue_head(&host->h_gracewait);
+        init_rwsem(&host->h_rwsem);
         host->h_state      = 0;                 /* pseudo NSM state */
         host->h_nsmstate   = 0;                 /* real NSM state */
         host->h_server     = server;
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index a6c1a33e5ae3..6b2684763fc7 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -50,6 +50,7 @@ struct nlm_host {
                                 h_killed     : 1,
                                 h_monitored  : 1;
         wait_queue_head_t       h_gracewait;    /* wait while reclaiming */
+        struct rw_semaphore     h_rwsem;        /* Reboot recovery lock */
         u32                     h_state;        /* pseudo-state counter */
         u32                     h_nsmstate;     /* true remote NSM state */
         u32                     h_pidcount;     /* Pseudopids */