[RFC 6/7] dlm: add more tracepoints for DLM kernel verifier

[Alexander Aring <aahringo@redhat.com>]

This patch adds more useful tracepoints for the kernel verifier. The
lock/unlock validation tracepoints are useful to store the request state
mode that the lock must change to, at this time the lock request cannot
fail anymore. (It can fail but there might be upcoming changes because
we can't deal with that e.g. -ENOMEM cases).

Another tracepoint is dlm_release_lockspace() that signals us that a
node is leaving the lockspace and all locks holding should be dropped.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lock.c              | 10 +++--
 fs/dlm/lockspace.c         |  4 ++
 include/trace/events/dlm.h | 80 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 21bb9603a0df..597418cba76a 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -2811,7 +2811,8 @@ static int set_unlock_args(uint32_t flags, void *astarg, struct dlm_args *args)
 }
 
 static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
-			      struct dlm_args *args)
+			      struct dlm_args *args, const char *res_name,
+			      size_t res_length)
 {
 	int rv = -EBUSY;
 
@@ -2845,6 +2846,7 @@ static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
 	lkb->lkb_lvbptr = args->lksb->sb_lvbptr;
 	lkb->lkb_ownpid = (int) current->pid;
 	lkb->lkb_rv_mode = args->mode;
+	trace_dlm_lock_validated(ls, lkb, args, res_name, res_length);
 	rv = 0;
  out:
 	switch (rv) {
@@ -2988,6 +2990,7 @@ static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
 	lkb->lkb_exflags |= args->flags;
 	dlm_set_sbflags_val(lkb, 0);
 	lkb->lkb_astparam = args->astparam;
+	trace_dlm_unlock_validated(ls, lkb, args);
 	rv = 0;
  out:
 	switch (rv) {
@@ -3264,7 +3267,7 @@ static int request_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
 	struct dlm_rsb *r;
 	int error;
 
-	error = validate_lock_args(ls, lkb, args);
+	error = validate_lock_args(ls, lkb, args, name, len);
 	if (error)
 		return error;
 
@@ -3295,7 +3298,8 @@ static int convert_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
 	hold_rsb(r);
 	lock_rsb(r);
 
-	error = validate_lock_args(ls, lkb, args);
+	error = validate_lock_args(ls, lkb, args, r->res_name,
+				   r->res_length);
 	if (error)
 		goto out;
 
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 092f7017b896..c19d797264c5 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -9,6 +9,8 @@
 *******************************************************************************
 ******************************************************************************/
 
+#include <trace/events/dlm.h>
+
 #include <linux/netdevice.h>
 #include <linux/module.h>
 
@@ -781,6 +783,8 @@ static int release_lockspace(struct dlm_net *dn, struct dlm_ls *ls, int force)
 		return rv;
 	}
 
+	trace_dlm_release_lockspace(dn->our_node->id, ls->ls_global_id);
+
 	if (dn->ls_count == 1)
 		dlm_midcomms_version_wait(ls->ls_dn);
 
diff --git a/include/trace/events/dlm.h b/include/trace/events/dlm.h
index f8d7ca451760..facad6251e43 100644
--- a/include/trace/events/dlm.h
+++ b/include/trace/events/dlm.h
@@ -338,6 +338,86 @@ TRACE_EVENT(dlm_unlock_end,
 
 );
 
+TRACE_EVENT(dlm_release_lockspace,
+
+	TP_PROTO(unsigned int our_nodeid, __u32 ls_id),
+
+	TP_ARGS(our_nodeid, ls_id),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, our_nodeid)
+		__field(__u32, ls_id)
+	),
+
+	TP_fast_assign(
+		__entry->our_nodeid = our_nodeid;
+		__entry->ls_id = ls_id;
+	),
+
+	TP_printk("our_nodeid=%u ls_id=%u",
+		  __entry->our_nodeid, __entry->ls_id)
+
+);
+
+TRACE_EVENT(dlm_lock_validated,
+
+	TP_PROTO(struct dlm_ls *ls, struct dlm_lkb *lkb, struct dlm_args *args,
+		 const char *res_name, size_t res_length),
+
+	TP_ARGS(ls, lkb, args, res_name, res_length),
+
+	TP_STRUCT__entry(
+		__field(uint32_t, our_nodeid)
+		__field(uint32_t, ls_id)
+		__dynamic_array(unsigned char, res_name, res_length)
+		__field(int, mode)
+	),
+
+	TP_fast_assign(
+		__entry->our_nodeid = ls->ls_dn->our_node->id;
+		__entry->ls_id = ls->ls_global_id;
+		memcpy(__get_dynamic_array(res_name), res_name,
+		       __get_dynamic_array_len(res_name));
+		__entry->mode = args->mode;
+	),
+
+	TP_printk("our_nodeid=%u ls_id=%u res_name=%s mode=%d",
+		  __entry->our_nodeid, __entry->ls_id,
+		  __print_hex_str(__get_dynamic_array(res_name),
+				  __get_dynamic_array_len(res_name)),
+		  __entry->mode)
+
+);
+
+TRACE_EVENT(dlm_unlock_validated,
+
+	TP_PROTO(struct dlm_ls *ls, struct dlm_lkb *lkb, struct dlm_args *args),
+
+	TP_ARGS(ls, lkb, args),
+
+	TP_STRUCT__entry(
+		__field(uint32_t, our_nodeid)
+		__field(uint32_t, ls_id)
+		__dynamic_array(unsigned char, res_name,
+				lkb->lkb_resource->res_length)
+	),
+
+	TP_fast_assign(
+		struct dlm_rsb *r = lkb->lkb_resource;
+
+		__entry->our_nodeid = ls->ls_dn->our_node->id;
+		__entry->ls_id = ls->ls_global_id;
+		memcpy(__get_dynamic_array(res_name), r->res_name,
+		       __get_dynamic_array_len(res_name));
+	),
+
+	TP_printk("our_nodeid=%u ls_id=%u res_name=%s",
+		  __entry->our_nodeid, __entry->ls_id,
+		  __print_hex_str(__get_dynamic_array(res_name),
+				  __get_dynamic_array_len(res_name)))
+
+);
+
 DECLARE_EVENT_CLASS(dlm_rcom_template,
 
 	TP_PROTO(uint32_t dst, uint32_t h_seq, const struct dlm_rcom *rc),
-- 
2.43.0