afs: Fix server reaping

Fix server reaping and make sure it's all done before we start trying to
purge cells, given that servers currently pin cells.

Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 53bd11d73469390620b347718e721049087ee016..bc9ded443b116de271fe85398ca2900e67507970 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -238,7 +238,9 @@ struct afs_net {
        rwlock_t                servers_lock;
        struct list_head        server_graveyard;       /* Inactive server LRU list */
        spinlock_t              server_graveyard_lock;
-       struct delayed_work     server_reaper;
+       struct timer_list       server_timer;
+       struct work_struct      server_reaper;
+       atomic_t                servers_outstanding;
 
        /* Misc */
        struct proc_dir_entry   *proc_afs;              /* /proc/net/afs directory */
@@ -700,6 +702,7 @@ do {                                                                \
        atomic_inc(&(S)->usage);                                \
 } while(0)
 
+extern void afs_server_timer(struct timer_list *);
 extern struct afs_server *afs_lookup_server(struct afs_cell *,
                                            const struct in_addr *);
 extern struct afs_server *afs_find_server(struct afs_net *,

diff --git a/fs/afs/main.c b/fs/afs/main.c
index 6bd2f3a426de3b80d3c76e9f82d56fb561e11a45..38e15b1f0eec708a1caca03a1af9f7e30d5dec02 100644 (file)
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -62,7 +62,8 @@ static int __net_init afs_net_init(struct afs_net *net)
        rwlock_init(&net->servers_lock);
        INIT_LIST_HEAD(&net->server_graveyard);
        spin_lock_init(&net->server_graveyard_lock);
-       INIT_DELAYED_WORK(&net->server_reaper, afs_reap_server);
+       INIT_WORK(&net->server_reaper, afs_reap_server);
+       timer_setup(&net->server_timer, afs_server_timer, 0);
 
        /* Register the /proc stuff */
        ret = afs_proc_init(net);

diff --git a/fs/afs/server.c b/fs/afs/server.c
index e47fd9bc0ddc55c3e3dc5afbc6179dced0bf54c8..33aeb527ac7e44f50a7c55ba6140225e3a1af6fb 100644 (file)
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -15,6 +15,25 @@
 
 static unsigned afs_server_timeout = 10;       /* server timeout in seconds */
 
+static void afs_inc_servers_outstanding(struct afs_net *net)
+{
+       atomic_inc(&net->servers_outstanding);
+}
+
+static void afs_dec_servers_outstanding(struct afs_net *net)
+{
+       if (atomic_dec_and_test(&net->servers_outstanding))
+               wake_up_atomic_t(&net->servers_outstanding);
+}
+
+void afs_server_timer(struct timer_list *timer)
+{
+       struct afs_net *net = container_of(timer, struct afs_net, server_timer);
+
+       if (!queue_work(afs_wq, &net->server_reaper))
+               afs_dec_servers_outstanding(net);
+}
+
 /*
  * install a server record in the master tree
  */
@@ -81,6 +100,7 @@ static struct afs_server *afs_alloc_server(struct afs_cell *cell,
 
                memcpy(&server->addr, addr, sizeof(struct in_addr));
                server->addr.s_addr = addr->s_addr;
+               afs_inc_servers_outstanding(cell->net);
                _leave(" = %p{%d}", server, atomic_read(&server->usage));
        } else {
                _leave(" = NULL [nomem]");
@@ -159,6 +179,7 @@ found_server:
 server_in_two_cells:
        write_unlock(&cell->servers_lock);
        kfree(candidate);
+       afs_dec_servers_outstanding(cell->net);
        printk(KERN_NOTICE "kAFS: Server %pI4 appears to be in two cells\n",
               addr);
        _leave(" = -EEXIST");
@@ -208,6 +229,18 @@ found:
        return server;
 }
 
+static void afs_set_server_timer(struct afs_net *net, time64_t delay)
+{
+       afs_inc_servers_outstanding(net);
+       if (net->live) {
+               if (timer_reduce(&net->server_timer, jiffies + delay * HZ))
+                       afs_dec_servers_outstanding(net);
+       } else {
+               if (!queue_work(afs_wq, &net->server_reaper))
+                       afs_dec_servers_outstanding(net);
+       }
+}
+
 /*
  * destroy a server record
  * - removes from the cell list
@@ -236,8 +269,7 @@ void afs_put_server(struct afs_server *server)
        if (atomic_read(&server->usage) == 0) {
                list_move_tail(&server->grave, &net->server_graveyard);
                server->time_of_death = ktime_get_real_seconds();
-               queue_delayed_work(afs_wq, &net->server_reaper,
-                                  net->live ? afs_server_timeout * HZ : 0);
+               afs_set_server_timer(net, afs_server_timeout);
        }
        spin_unlock(&net->server_graveyard_lock);
        _leave(" [dead]");
@@ -246,7 +278,7 @@ void afs_put_server(struct afs_server *server)
 /*
  * destroy a dead server
  */
-static void afs_destroy_server(struct afs_server *server)
+static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
 {
        _enter("%p", server);
 
@@ -260,6 +292,7 @@ static void afs_destroy_server(struct afs_server *server)
 
        afs_put_cell(server->cell);
        kfree(server);
+       afs_dec_servers_outstanding(net);
 }
 
 /*
@@ -269,7 +302,7 @@ void afs_reap_server(struct work_struct *work)
 {
        LIST_HEAD(corpses);
        struct afs_server *server;
-       struct afs_net *net = container_of(work, struct afs_net, server_reaper.work);
+       struct afs_net *net = container_of(work, struct afs_net, server_reaper);
        unsigned long delay, expiry;
        time64_t now;
 
@@ -284,8 +317,8 @@ void afs_reap_server(struct work_struct *work)
                if (net->live) {
                        expiry = server->time_of_death + afs_server_timeout;
                        if (expiry > now) {
-                               delay = (expiry - now) * HZ;
-                               mod_delayed_work(afs_wq, &net->server_reaper, delay);
+                               delay = (expiry - now);
+                               afs_set_server_timer(net, delay);
                                break;
                        }
                }
@@ -309,8 +342,10 @@ void afs_reap_server(struct work_struct *work)
        while (!list_empty(&corpses)) {
                server = list_entry(corpses.next, struct afs_server, grave);
                list_del(&server->grave);
-               afs_destroy_server(server);
+               afs_destroy_server(net, server);
        }
+
+       afs_dec_servers_outstanding(net);
 }
 
 /*
@@ -319,5 +354,13 @@ void afs_reap_server(struct work_struct *work)
  */
 void __net_exit afs_purge_servers(struct afs_net *net)
 {
-       mod_delayed_work(afs_wq, &net->server_reaper, 0);
+       if (del_timer_sync(&net->server_timer))
+               atomic_dec(&net->servers_outstanding);
+
+       afs_inc_servers_outstanding(net);
+       if (!queue_work(afs_wq, &net->server_reaper))
+               afs_dec_servers_outstanding(net);
+
+       wait_on_atomic_t(&net->servers_outstanding, atomic_t_wait,
+                        TASK_UNINTERRUPTIBLE);
 }