fscache: Add tracepoints
Add some tracepoints to fscache:
(*) fscache_cookie - Tracks a cookie's usage count.
(*) fscache_netfs - Logs registration of a network filesystem, including
the pointer to the cookie allocated.
(*) fscache_acquire - Logs cookie acquisition.
(*) fscache_relinquish - Logs cookie relinquishment.
(*) fscache_enable - Logs enablement of a cookie.
(*) fscache_disable - Logs disablement of a cookie.
(*) fscache_osm - Tracks execution of states in the object state machine.
and cachefiles:
(*) cachefiles_ref - Tracks a cachefiles object's usage count.
(*) cachefiles_lookup - Logs result of lookup_one_len().
(*) cachefiles_mkdir - Logs result of vfs_mkdir().
(*) cachefiles_create - Logs result of vfs_create().
(*) cachefiles_unlink - Logs calls to vfs_unlink().
(*) cachefiles_rename - Logs calls to vfs_rename().
(*) cachefiles_mark_active - Logs an object becoming active.
(*) cachefiles_wait_active - Logs a wait for an old object to be
destroyed.
(*) cachefiles_mark_inactive - Logs an object becoming inactive.
(*) cachefiles_mark_buried - Logs the burial of an object.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 98d22f4..20bc334 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -101,7 +101,7 @@ struct fscache_cookie *__fscache_acquire_cookie(
*/
atomic_set(&cookie->n_active, 1);
- atomic_inc(&parent->usage);
+ fscache_cookie_get(parent, fscache_cookie_get_acquire_parent);
atomic_inc(&parent->n_children);
cookie->def = def;
@@ -125,6 +125,8 @@ struct fscache_cookie *__fscache_acquire_cookie(
break;
}
+ trace_fscache_acquire(cookie);
+
if (enable) {
/* if the object is an index then we need do nothing more here
* - we create indices on disk when we need them as an index
@@ -134,7 +136,8 @@ struct fscache_cookie *__fscache_acquire_cookie(
set_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags);
} else {
atomic_dec(&parent->n_children);
- __fscache_cookie_put(cookie);
+ fscache_cookie_put(cookie,
+ fscache_cookie_put_acquire_nobufs);
fscache_stat(&fscache_n_acquires_nobufs);
_leave(" = NULL");
return NULL;
@@ -159,6 +162,8 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie,
{
_enter("%p", cookie);
+ trace_fscache_enable(cookie);
+
wait_on_bit_lock(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK,
TASK_UNINTERRUPTIBLE);
@@ -318,7 +323,7 @@ static int fscache_alloc_object(struct fscache_cache *cache,
* attached to the cookie */
if (fscache_attach_object(cookie, object) < 0) {
fscache_stat(&fscache_n_cop_put_object);
- cache->ops->put_object(object);
+ cache->ops->put_object(object, fscache_obj_put_attach_fail);
fscache_stat_d(&fscache_n_cop_put_object);
}
@@ -338,7 +343,7 @@ static int fscache_alloc_object(struct fscache_cache *cache,
error_put:
fscache_stat(&fscache_n_cop_put_object);
- cache->ops->put_object(object);
+ cache->ops->put_object(object, fscache_obj_put_alloc_fail);
fscache_stat_d(&fscache_n_cop_put_object);
error:
_leave(" = %d", ret);
@@ -398,7 +403,7 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
/* attach to the cookie */
object->cookie = cookie;
- atomic_inc(&cookie->usage);
+ fscache_cookie_get(cookie, fscache_cookie_get_attach_object);
hlist_add_head(&object->cookie_link, &cookie->backing_objects);
fscache_objlist_add(object);
@@ -516,6 +521,8 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate)
_enter("%p,%u", cookie, invalidate);
+ trace_fscache_disable(cookie);
+
ASSERTCMP(atomic_read(&cookie->n_active), >, 0);
if (atomic_read(&cookie->n_children) != 0) {
@@ -601,6 +608,8 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
cookie, cookie->def->name, cookie->netfs_data,
atomic_read(&cookie->n_active), retire);
+ trace_fscache_relinquish(cookie, retire);
+
/* No further netfs-accessing operations on this cookie permitted */
if (test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags))
BUG();
@@ -620,35 +629,38 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
/* Dispose of the netfs's link to the cookie */
ASSERTCMP(atomic_read(&cookie->usage), >, 0);
- fscache_cookie_put(cookie);
+ fscache_cookie_put(cookie, fscache_cookie_put_relinquish);
_leave("");
}
EXPORT_SYMBOL(__fscache_relinquish_cookie);
/*
- * destroy a cookie
+ * Drop a reference to a cookie.
*/
-void __fscache_cookie_put(struct fscache_cookie *cookie)
+void fscache_cookie_put(struct fscache_cookie *cookie,
+ enum fscache_cookie_trace where)
{
struct fscache_cookie *parent;
+ int usage;
_enter("%p", cookie);
- for (;;) {
- _debug("FREE COOKIE %p", cookie);
+ do {
+ usage = atomic_dec_return(&cookie->usage);
+ trace_fscache_cookie(cookie, where, usage);
+
+ if (usage > 0)
+ return;
+ BUG_ON(usage < 0);
+
parent = cookie->parent;
BUG_ON(!hlist_empty(&cookie->backing_objects));
kmem_cache_free(fscache_cookie_jar, cookie);
- if (!parent)
- break;
-
cookie = parent;
- BUG_ON(atomic_read(&cookie->usage) <= 0);
- if (!atomic_dec_and_test(&cookie->usage))
- break;
- }
+ where = fscache_cookie_put_parent;
+ } while (cookie);
_leave("");
}