cachefiles: Implement object lifecycle funcs

Implement allocate, get, see and put functions for the cachefiles_object
struct.  The members of the struct we're going to need are also added.

Additionally, implement a lifecycle tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819639457.215744.4600093239395728232.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906939569.143852.3594314410666551982.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967148857.1823006.6332962598220464364.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021547762.640689.8422781599594931000.stgit@warthog.procyon.org.uk/ # v4

1 files changed, 58 insertions, 0 deletions

diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 5975ea4977b2..54815cc776ba 100644
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -18,6 +18,21 @@
 #ifndef __CACHEFILES_DECLARE_TRACE_ENUMS_ONCE_ONLY
 #define __CACHEFILES_DECLARE_TRACE_ENUMS_ONCE_ONLY
 
+enum cachefiles_obj_ref_trace {
+	cachefiles_obj_get_ioreq,
+	cachefiles_obj_new,
+	cachefiles_obj_put_alloc_fail,
+	cachefiles_obj_put_detach,
+	cachefiles_obj_put_ioreq,
+	cachefiles_obj_see_clean_commit,
+	cachefiles_obj_see_clean_delete,
+	cachefiles_obj_see_clean_drop_tmp,
+	cachefiles_obj_see_lookup_cookie,
+	cachefiles_obj_see_lookup_failed,
+	cachefiles_obj_see_withdraw_cookie,
+	cachefiles_obj_see_withdrawal,
+};
+
 enum fscache_why_object_killed {
 	FSCACHE_OBJECT_IS_STALE,
 	FSCACHE_OBJECT_IS_WEIRD,
@@ -66,6 +81,20 @@ enum cachefiles_error_trace {
 	EM(FSCACHE_OBJECT_WAS_RETIRED,	"was_retired")		\
 	E_(FSCACHE_OBJECT_WAS_CULLED,	"was_culled")
 
+#define cachefiles_obj_ref_traces					\
+	EM(cachefiles_obj_get_ioreq,		"GET ioreq")		\
+	EM(cachefiles_obj_new,			"NEW obj")		\
+	EM(cachefiles_obj_put_alloc_fail,	"PUT alloc_fail")	\
+	EM(cachefiles_obj_put_detach,		"PUT detach")		\
+	EM(cachefiles_obj_put_ioreq,		"PUT ioreq")		\
+	EM(cachefiles_obj_see_clean_commit,	"SEE clean_commit")	\
+	EM(cachefiles_obj_see_clean_delete,	"SEE clean_delete")	\
+	EM(cachefiles_obj_see_clean_drop_tmp,	"SEE clean_drop_tmp")	\
+	EM(cachefiles_obj_see_lookup_cookie,	"SEE lookup_cookie")	\
+	EM(cachefiles_obj_see_lookup_failed,	"SEE lookup_failed")	\
+	EM(cachefiles_obj_see_withdraw_cookie,	"SEE withdraw_cookie")	\
+	E_(cachefiles_obj_see_withdrawal,	"SEE withdrawal")
+
 #define cachefiles_trunc_traces						\
 	EM(cachefiles_trunc_dio_adjust,		"DIOADJ")		\
 	EM(cachefiles_trunc_expand_tmpfile,	"EXPTMP")		\
@@ -100,6 +129,7 @@ enum cachefiles_error_trace {
 #define E_(a, b) TRACE_DEFINE_ENUM(a);
 
 cachefiles_obj_kill_traces;
+cachefiles_obj_ref_traces;
 cachefiles_trunc_traces;
 cachefiles_error_traces;
 
@@ -113,6 +143,34 @@ cachefiles_error_traces;
 #define E_(a, b)	{ a, b }
 
 
+TRACE_EVENT(cachefiles_ref,
+	    TP_PROTO(unsigned int object_debug_id,
+		     unsigned int cookie_debug_id,
+		     int usage,
+		     enum cachefiles_obj_ref_trace why),
+
+	    TP_ARGS(object_debug_id, cookie_debug_id, usage, why),
+
+	    /* Note that obj may be NULL */
+	    TP_STRUCT__entry(
+		    __field(unsigned int,			obj		)
+		    __field(unsigned int,			cookie		)
+		    __field(enum cachefiles_obj_ref_trace,	why		)
+		    __field(int,				usage		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->obj	= object_debug_id;
+		    __entry->cookie	= cookie_debug_id;
+		    __entry->usage	= usage;
+		    __entry->why	= why;
+			   ),
+
+	    TP_printk("c=%08x o=%08x u=%d %s",
+		      __entry->cookie, __entry->obj, __entry->usage,
+		      __print_symbolic(__entry->why, cachefiles_obj_ref_traces))
+	    );
+
 TRACE_EVENT(cachefiles_lookup,
 	    TP_PROTO(struct cachefiles_object *obj,
 		     struct dentry *de),