1 files changed, 93 insertions, 11 deletions

diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 392a41b1b79d..e513ac599c8e 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -14,9 +14,10 @@
 
 #define FSCACHE_DEBUG_LEVEL COOKIE
 #include <linux/module.h>
+#include <linux/seq_file.h>
 #include "internal.h"
 
-const char *fscache_object_states[] = {
+const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = {
         [FSCACHE_OBJECT_INIT]           = "OBJECT_INIT",
         [FSCACHE_OBJECT_LOOKING_UP]     = "OBJECT_LOOKING_UP",
         [FSCACHE_OBJECT_CREATING]       = "OBJECT_CREATING",
@@ -33,9 +34,28 @@ const char *fscache_object_states[] = {
 };
 EXPORT_SYMBOL(fscache_object_states);
 
+const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = {
+        [FSCACHE_OBJECT_INIT]           = "INIT",
+        [FSCACHE_OBJECT_LOOKING_UP]     = "LOOK",
+        [FSCACHE_OBJECT_CREATING]       = "CRTN",
+        [FSCACHE_OBJECT_AVAILABLE]      = "AVBL",
+        [FSCACHE_OBJECT_ACTIVE]         = "ACTV",
+        [FSCACHE_OBJECT_UPDATING]       = "UPDT",
+        [FSCACHE_OBJECT_DYING]          = "DYNG",
+        [FSCACHE_OBJECT_LC_DYING]       = "LCDY",
+        [FSCACHE_OBJECT_ABORT_INIT]     = "ABTI",
+        [FSCACHE_OBJECT_RELEASING]      = "RELS",
+        [FSCACHE_OBJECT_RECYCLING]      = "RCYC",
+        [FSCACHE_OBJECT_WITHDRAWING]    = "WTHD",
+        [FSCACHE_OBJECT_DEAD]           = "DEAD",
+};
+
 static void fscache_object_slow_work_put_ref(struct slow_work *);
 static int  fscache_object_slow_work_get_ref(struct slow_work *);
 static void fscache_object_slow_work_execute(struct slow_work *);
+#ifdef CONFIG_SLOW_WORK_PROC
+static void fscache_object_slow_work_desc(struct slow_work *, struct seq_file *);
+#endif
 static void fscache_initialise_object(struct fscache_object *);
 static void fscache_lookup_object(struct fscache_object *);
 static void fscache_object_available(struct fscache_object *);
@@ -45,9 +65,13 @@ static void fscache_enqueue_dependents(struct fscache_object *);
 static void fscache_dequeue_object(struct fscache_object *);
 
 const struct slow_work_ops fscache_object_slow_work_ops = {
+        .owner          = THIS_MODULE,
         .get_ref        = fscache_object_slow_work_get_ref,
         .put_ref        = fscache_object_slow_work_put_ref,
         .execute        = fscache_object_slow_work_execute,
+#ifdef CONFIG_SLOW_WORK_PROC
+        .desc           = fscache_object_slow_work_desc,
+#endif
 };
 EXPORT_SYMBOL(fscache_object_slow_work_ops);
 
@@ -81,6 +105,7 @@ static inline void fscache_done_parent_op(struct fscache_object *object)
 static void fscache_object_state_machine(struct fscache_object *object)
 {
         enum fscache_object_state new_state;
+        struct fscache_cookie *cookie;
 
         ASSERT(object != NULL);
 
@@ -120,20 +145,31 @@ static void fscache_object_state_machine(struct fscache_object *object)
         case FSCACHE_OBJECT_UPDATING:
                 clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events);
                 fscache_stat(&fscache_n_updates_run);
+                fscache_stat(&fscache_n_cop_update_object);
                 object->cache->ops->update_object(object);
+                fscache_stat_d(&fscache_n_cop_update_object);
                 goto active_transit;
 
                 /* handle an object dying during lookup or creation */
         case FSCACHE_OBJECT_LC_DYING:
                 object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
+                fscache_stat(&fscache_n_cop_lookup_complete);
                 object->cache->ops->lookup_complete(object);
+                fscache_stat_d(&fscache_n_cop_lookup_complete);
 
                 spin_lock(&object->lock);
                 object->state = FSCACHE_OBJECT_DYING;
-                if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
-                                       &object->cookie->flags))
-                        wake_up_bit(&object->cookie->flags,
-                                    FSCACHE_COOKIE_CREATING);
+                cookie = object->cookie;
+                if (cookie) {
+                        if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP,
+                                               &cookie->flags))
+                                wake_up_bit(&cookie->flags,
+                                            FSCACHE_COOKIE_LOOKING_UP);
+                        if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
+                                               &cookie->flags))
+                                wake_up_bit(&cookie->flags,
+                                            FSCACHE_COOKIE_CREATING);
+                }
                 spin_unlock(&object->lock);
 
                 fscache_done_parent_op(object);
@@ -165,6 +201,7 @@ static void fscache_object_state_machine(struct fscache_object *object)
                 }
                 spin_unlock(&object->lock);
                 fscache_enqueue_dependents(object);
+                fscache_start_operations(object);
                 goto terminal_transit;
 
                 /* handle an abort during initialisation */
@@ -316,14 +353,29 @@ static void fscache_object_slow_work_execute(struct slow_work *work)
 
         _enter("{OBJ%x}", object->debug_id);
 
-        clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
-
         start = jiffies;
         fscache_object_state_machine(object);
         fscache_hist(fscache_objs_histogram, start);
         if (object->events & object->event_mask)
                 fscache_enqueue_object(object);
+        clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+}
+
+/*
+ * describe an object for slow-work debugging
+ */
+#ifdef CONFIG_SLOW_WORK_PROC
+static void fscache_object_slow_work_desc(struct slow_work *work,
+                                          struct seq_file *m)
+{
+        struct fscache_object *object =
+                container_of(work, struct fscache_object, work);
+
+        seq_printf(m, "FSC: OBJ%x: %s",
+                   object->debug_id,
+                   fscache_object_states_short[object->state]);
 }
+#endif
 
 /*
  * initialise an object
@@ -376,7 +428,9 @@ static void fscache_initialise_object(struct fscache_object *object)
                          * binding on to us, so we need to make sure we don't
                          * add ourself to the list multiple times */
                         if (list_empty(&object->dep_link)) {
+                                fscache_stat(&fscache_n_cop_grab_object);
                                 object->cache->ops->grab_object(object);
+                                fscache_stat_d(&fscache_n_cop_grab_object);
                                 list_add(&object->dep_link,
                                          &parent->dependents);
 
@@ -414,6 +468,7 @@ static void fscache_lookup_object(struct fscache_object *object)
 {
         struct fscache_cookie *cookie = object->cookie;
         struct fscache_object *parent;
+        int ret;
 
         _enter("");
 
@@ -438,11 +493,20 @@ static void fscache_lookup_object(struct fscache_object *object)
                object->cache->tag->name);
 
         fscache_stat(&fscache_n_object_lookups);
-        object->cache->ops->lookup_object(object);
+        fscache_stat(&fscache_n_cop_lookup_object);
+        ret = object->cache->ops->lookup_object(object);
+        fscache_stat_d(&fscache_n_cop_lookup_object);
 
         if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events))
                 set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
 
+        if (ret == -ETIMEDOUT) {
+                /* probably stuck behind another object, so move this one to
+                 * the back of the queue */
+                fscache_stat(&fscache_n_object_lookups_timed_out);
+                set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+        }
+
         _leave("");
 }
 
@@ -546,7 +610,8 @@ static void fscache_object_available(struct fscache_object *object)
 
         spin_lock(&object->lock);
 
-        if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
+        if (object->cookie &&
+            test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
                 wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING);
 
         fscache_done_parent_op(object);
@@ -562,7 +627,9 @@ static void fscache_object_available(struct fscache_object *object)
         }
         spin_unlock(&object->lock);
 
+        fscache_stat(&fscache_n_cop_lookup_complete);
         object->cache->ops->lookup_complete(object);
+        fscache_stat_d(&fscache_n_cop_lookup_complete);
         fscache_enqueue_dependents(object);
 
         fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif);
@@ -581,11 +648,16 @@ static void fscache_drop_object(struct fscache_object *object)
 
         _enter("{OBJ%x,%d}", object->debug_id, object->n_children);
 
+        ASSERTCMP(object->cookie, ==, NULL);
+        ASSERT(hlist_unhashed(&object->cookie_link));
+
         spin_lock(&cache->object_list_lock);
         list_del_init(&object->cache_link);
         spin_unlock(&cache->object_list_lock);
 
+        fscache_stat(&fscache_n_cop_drop_object);
         cache->ops->drop_object(object);
+        fscache_stat_d(&fscache_n_cop_drop_object);
 
         if (parent) {
                 _debug("release parent OBJ%x {%d}",
@@ -600,7 +672,9 @@ static void fscache_drop_object(struct fscache_object *object)
         }
 
         /* this just shifts the object release to the slow work processor */
+        fscache_stat(&fscache_n_cop_put_object);
         object->cache->ops->put_object(object);
+        fscache_stat_d(&fscache_n_cop_put_object);
 
         _leave("");
 }
@@ -690,8 +764,12 @@ static int fscache_object_slow_work_get_ref(struct slow_work *work)
 {
         struct fscache_object *object =
                 container_of(work, struct fscache_object, work);
+        int ret;
 
-        return object->cache->ops->grab_object(object) ? 0 : -EAGAIN;
+        fscache_stat(&fscache_n_cop_grab_object);
+        ret = object->cache->ops->grab_object(object) ? 0 : -EAGAIN;
+        fscache_stat_d(&fscache_n_cop_grab_object);
+        return ret;
 }
 
 /*
@@ -702,7 +780,9 @@ static void fscache_object_slow_work_put_ref(struct slow_work *work)
         struct fscache_object *object =
                 container_of(work, struct fscache_object, work);
 
-        return object->cache->ops->put_object(object);
+        fscache_stat(&fscache_n_cop_put_object);
+        object->cache->ops->put_object(object);
+        fscache_stat_d(&fscache_n_cop_put_object);
 }
 
 /*
@@ -739,7 +819,9 @@ static void fscache_enqueue_dependents(struct fscache_object *object)
 
                 /* sort onto appropriate lists */
                 fscache_enqueue_object(dep);
+                fscache_stat(&fscache_n_cop_put_object);
                 dep->cache->ops->put_object(dep);
+                fscache_stat_d(&fscache_n_cop_put_object);
 
                 if (!list_empty(&object->dependents))
                         cond_resched_lock(&object->lock);