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>

1 files changed, 16 insertions, 2 deletions

diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index b19fa8592fc2..fbe102f37074 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -29,6 +29,18 @@ struct fscache_cache_ops;
 struct fscache_object;
 struct fscache_operation;
 
+enum fscache_obj_ref_trace {
+	fscache_obj_get_add_to_deps,
+	fscache_obj_get_queue,
+	fscache_obj_put_alloc_fail,
+	fscache_obj_put_attach_fail,
+	fscache_obj_put_drop_obj,
+	fscache_obj_put_enq_dep,
+	fscache_obj_put_queue,
+	fscache_obj_put_work,
+	fscache_obj_ref__nr_traces
+};
+
 /*
  * cache tag definition
  */
@@ -231,7 +243,8 @@ struct fscache_cache_ops {
 	void (*lookup_complete)(struct fscache_object *object);
 
 	/* increment the usage count on this object (may fail if unmounting) */
-	struct fscache_object *(*grab_object)(struct fscache_object *object);
+	struct fscache_object *(*grab_object)(struct fscache_object *object,
+					      enum fscache_obj_ref_trace why);
 
 	/* pin an object in the cache */
 	int (*pin_object)(struct fscache_object *object);
@@ -254,7 +267,8 @@ struct fscache_cache_ops {
 	void (*drop_object)(struct fscache_object *object);
 
 	/* dispose of a reference to an object */
-	void (*put_object)(struct fscache_object *object);
+	void (*put_object)(struct fscache_object *object,
+			   enum fscache_obj_ref_trace why);
 
 	/* sync a cache */
 	void (*sync_cache)(struct fscache_cache *cache);