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-rw-r--r--fs/afs/server.c151
1 files changed, 100 insertions, 51 deletions
diff --git a/fs/afs/server.c b/fs/afs/server.c
index 9e50ccde5d37..4969a681f8f5 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -25,6 +25,10 @@ static void afs_dec_servers_outstanding(struct afs_net *net)
wake_up_var(&net->servers_outstanding);
}
+static struct afs_server *afs_maybe_use_server(struct afs_server *,
+ enum afs_server_trace);
+static void __afs_put_server(struct afs_net *, struct afs_server *);
+
/*
* Find a server by one of its addresses.
*/
@@ -40,7 +44,7 @@ struct afs_server *afs_find_server(struct afs_net *net,
do {
if (server)
- afs_put_server(net, server, afs_server_trace_put_find_rsq);
+ afs_unuse_server_notime(net, server, afs_server_trace_put_find_rsq);
server = NULL;
read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
@@ -78,9 +82,9 @@ struct afs_server *afs_find_server(struct afs_net *net,
}
server = NULL;
+ continue;
found:
- if (server && !atomic_inc_not_zero(&server->usage))
- server = NULL;
+ server = afs_maybe_use_server(server, afs_server_trace_get_by_addr);
} while (need_seqretry(&net->fs_addr_lock, seq));
@@ -91,7 +95,7 @@ struct afs_server *afs_find_server(struct afs_net *net,
}
/*
- * Look up a server by its UUID
+ * Look up a server by its UUID and mark it active.
*/
struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
{
@@ -107,7 +111,7 @@ struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uu
* changes.
*/
if (server)
- afs_put_server(net, server, afs_server_trace_put_uuid_rsq);
+ afs_unuse_server(net, server, afs_server_trace_put_uuid_rsq);
server = NULL;
read_seqbegin_or_lock(&net->fs_lock, &seq);
@@ -122,7 +126,7 @@ struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uu
} else if (diff > 0) {
p = p->rb_right;
} else {
- afs_get_server(server, afs_server_trace_get_by_uuid);
+ afs_use_server(server, afs_server_trace_get_by_uuid);
break;
}
@@ -198,7 +202,7 @@ exists:
}
/*
- * allocate a new server record
+ * Allocate a new server record and mark it active.
*/
static struct afs_server *afs_alloc_server(struct afs_net *net,
const uuid_t *uuid,
@@ -212,7 +216,8 @@ static struct afs_server *afs_alloc_server(struct afs_net *net,
if (!server)
goto enomem;
- atomic_set(&server->usage, 1);
+ atomic_set(&server->ref, 1);
+ atomic_set(&server->active, 1);
server->debug_id = atomic_inc_return(&afs_server_debug_id);
RCU_INIT_POINTER(server->addresses, alist);
server->addr_version = alist->version;
@@ -224,7 +229,7 @@ static struct afs_server *afs_alloc_server(struct afs_net *net,
spin_lock_init(&server->probe_lock);
afs_inc_servers_outstanding(net);
- trace_afs_server(server, 1, afs_server_trace_alloc);
+ trace_afs_server(server, 1, 1, afs_server_trace_alloc);
_leave(" = %p", server);
return server;
@@ -292,7 +297,6 @@ struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
kfree(candidate);
}
- _leave(" = %p{%d}", server, atomic_read(&server->usage));
return server;
}
@@ -328,9 +332,38 @@ void afs_servers_timer(struct timer_list *timer)
struct afs_server *afs_get_server(struct afs_server *server,
enum afs_server_trace reason)
{
- unsigned int u = atomic_inc_return(&server->usage);
+ unsigned int u = atomic_inc_return(&server->ref);
+
+ trace_afs_server(server, u, atomic_read(&server->active), reason);
+ return server;
+}
+
+/*
+ * Try to get a reference on a server object.
+ */
+static struct afs_server *afs_maybe_use_server(struct afs_server *server,
+ enum afs_server_trace reason)
+{
+ unsigned int r = atomic_fetch_add_unless(&server->ref, 1, 0);
+ unsigned int a;
+
+ if (r == 0)
+ return NULL;
+
+ a = atomic_inc_return(&server->active);
+ trace_afs_server(server, r, a, reason);
+ return server;
+}
+
+/*
+ * Get an active count on a server object.
+ */
+struct afs_server *afs_use_server(struct afs_server *server, enum afs_server_trace reason)
+{
+ unsigned int r = atomic_inc_return(&server->ref);
+ unsigned int a = atomic_inc_return(&server->active);
- trace_afs_server(server, u, reason);
+ trace_afs_server(server, r, a, reason);
return server;
}
@@ -345,28 +378,56 @@ void afs_put_server(struct afs_net *net, struct afs_server *server,
if (!server)
return;
- server->put_time = ktime_get_real_seconds();
-
- usage = atomic_dec_return(&server->usage);
+ usage = atomic_dec_return(&server->ref);
+ trace_afs_server(server, usage, atomic_read(&server->active), reason);
+ if (unlikely(usage == 0))
+ __afs_put_server(net, server);
+}
- trace_afs_server(server, usage, reason);
+/*
+ * Drop an active count on a server object without updating the last-unused
+ * time.
+ */
+void afs_unuse_server_notime(struct afs_net *net, struct afs_server *server,
+ enum afs_server_trace reason)
+{
+ if (server) {
+ unsigned int active = atomic_dec_return(&server->active);
- if (likely(usage > 0))
- return;
+ if (active == 0)
+ afs_set_server_timer(net, afs_server_gc_delay);
+ afs_put_server(net, server, reason);
+ }
+}
- afs_set_server_timer(net, afs_server_gc_delay);
+/*
+ * Drop an active count on a server object.
+ */
+void afs_unuse_server(struct afs_net *net, struct afs_server *server,
+ enum afs_server_trace reason)
+{
+ if (server) {
+ server->unuse_time = ktime_get_real_seconds();
+ afs_unuse_server_notime(net, server, reason);
+ }
}
static void afs_server_rcu(struct rcu_head *rcu)
{
struct afs_server *server = container_of(rcu, struct afs_server, rcu);
- trace_afs_server(server, atomic_read(&server->usage),
- afs_server_trace_free);
+ trace_afs_server(server, atomic_read(&server->ref),
+ atomic_read(&server->active), afs_server_trace_free);
afs_put_addrlist(rcu_access_pointer(server->addresses));
kfree(server);
}
+static void __afs_put_server(struct afs_net *net, struct afs_server *server)
+{
+ call_rcu(&server->rcu, afs_server_rcu);
+ afs_dec_servers_outstanding(net);
+}
+
/*
* destroy a dead server
*/
@@ -379,19 +440,10 @@ static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
.error = 0,
};
- trace_afs_server(server, atomic_read(&server->usage),
- afs_server_trace_give_up_cb);
-
if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
- wait_var_event(&server->probe_outstanding,
- atomic_read(&server->probe_outstanding) == 0);
-
- trace_afs_server(server, atomic_read(&server->usage),
- afs_server_trace_destroy);
- call_rcu(&server->rcu, afs_server_rcu);
- afs_dec_servers_outstanding(net);
+ afs_put_server(net, server, afs_server_trace_destroy);
}
/*
@@ -400,31 +452,28 @@ static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
{
struct afs_server *server;
- bool deleted;
- int usage;
+ int active;
while ((server = gc_list)) {
gc_list = server->gc_next;
write_seqlock(&net->fs_lock);
- usage = 1;
- deleted = atomic_try_cmpxchg(&server->usage, &usage, 0);
- trace_afs_server(server, usage, afs_server_trace_gc);
- if (deleted) {
+
+ active = atomic_read(&server->active);
+ if (active == 0) {
+ trace_afs_server(server, atomic_read(&server->ref),
+ active, afs_server_trace_gc);
rb_erase(&server->uuid_rb, &net->fs_servers);
hlist_del_rcu(&server->proc_link);
- }
- write_sequnlock(&net->fs_lock);
-
- if (deleted) {
- write_seqlock(&net->fs_addr_lock);
if (!hlist_unhashed(&server->addr4_link))
hlist_del_rcu(&server->addr4_link);
if (!hlist_unhashed(&server->addr6_link))
hlist_del_rcu(&server->addr6_link);
- write_sequnlock(&net->fs_addr_lock);
- afs_destroy_server(net, server);
}
+ write_sequnlock(&net->fs_lock);
+
+ if (active == 0)
+ afs_destroy_server(net, server);
}
}
@@ -453,15 +502,14 @@ void afs_manage_servers(struct work_struct *work)
for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
struct afs_server *server =
rb_entry(cursor, struct afs_server, uuid_rb);
- int usage = atomic_read(&server->usage);
+ int active = atomic_read(&server->active);
- _debug("manage %pU %u", &server->uuid, usage);
+ _debug("manage %pU %u", &server->uuid, active);
- ASSERTCMP(usage, >=, 1);
- ASSERTIFCMP(purging, usage, ==, 1);
+ ASSERTIFCMP(purging, active, ==, 0);
- if (usage == 1) {
- time64_t expire_at = server->put_time;
+ if (active == 0) {
+ time64_t expire_at = server->unuse_time;
if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
!test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
@@ -532,7 +580,8 @@ static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct a
_enter("");
- trace_afs_server(server, atomic_read(&server->usage), afs_server_trace_update);
+ trace_afs_server(server, atomic_read(&server->ref), atomic_read(&server->active),
+ afs_server_trace_update);
alist = afs_vl_lookup_addrs(fc->vnode->volume->cell, fc->key,
&server->uuid);