fs: dlm: trace user space callbacks

This patch adds trace callbacks for user locks. Unfortenately user locks
are handled in a different way than kernel locks in some cases. User
locks never call the dlm_lock()/dlm_unlock() kernel API and use the next
step internal API of dlm. Adding those traces from user API callers
should make it possible for dlm trace system to see lock handling for
user locks as well.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/lock.c

@@ -3466,7 +3466,7 @@ int dlm_lock(dlm_lockspace_t *lockspace,
 	if (error == -EINPROGRESS)
 		error = 0;
  out_put:
-	trace_dlm_lock_end(ls, lkb, name, namelen, mode, flags, error);
+	trace_dlm_lock_end(ls, lkb, name, namelen, mode, flags, error, true);
 
 	if (convert || error)
 		__put_lkb(ls, lkb);
@@ -5842,13 +5842,15 @@ int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua,
 		goto out;
 	}
 
+	trace_dlm_lock_start(ls, lkb, name, namelen, mode, flags);
+
 	if (flags & DLM_LKF_VALBLK) {
 		ua->lksb.sb_lvbptr = kzalloc(DLM_USER_LVB_LEN, GFP_NOFS);
 		if (!ua->lksb.sb_lvbptr) {
 			kfree(ua);
 			__put_lkb(ls, lkb);
 			error = -ENOMEM;
-			goto out;
+			goto out_trace_end;
 		}
 	}
 #ifdef CONFIG_DLM_DEPRECATED_API
@@ -5863,7 +5865,7 @@ int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua,
 		ua->lksb.sb_lvbptr = NULL;
 		kfree(ua);
 		__put_lkb(ls, lkb);
-		goto out;
+		goto out_trace_end;
 	}
 
 	/* After ua is attached to lkb it will be freed by dlm_free_lkb().
@@ -5883,7 +5885,7 @@ int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua,
 		fallthrough;
 	default:
 		__put_lkb(ls, lkb);
-		goto out;
+		goto out_trace_end;
 	}
 
 	/* add this new lkb to the per-process list of locks */
@@ -5891,6 +5893,8 @@ int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua,
 	hold_lkb(lkb);
 	list_add_tail(&lkb->lkb_ownqueue, &ua->proc->locks);
 	spin_unlock(&ua->proc->locks_spin);
+ out_trace_end:
+	trace_dlm_lock_end(ls, lkb, name, namelen, mode, flags, error, false);
  out:
 	dlm_unlock_recovery(ls);
 	return error;
@@ -5916,6 +5920,8 @@ int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	if (error)
 		goto out;
 
+	trace_dlm_lock_start(ls, lkb, NULL, 0, mode, flags);
+
 	/* user can change the params on its lock when it converts it, or
 	   add an lvb that didn't exist before */
 
@@ -5953,6 +5959,7 @@ int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	if (error == -EINPROGRESS || error == -EAGAIN || error == -EDEADLK)
 		error = 0;
  out_put:
+	trace_dlm_lock_end(ls, lkb, NULL, 0, mode, flags, error, false);
 	dlm_put_lkb(lkb);
  out:
 	dlm_unlock_recovery(ls);
@@ -6045,6 +6052,8 @@ int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	if (error)
 		goto out;
 
+	trace_dlm_unlock_start(ls, lkb, flags);
+
 	ua = lkb->lkb_ua;
 
 	if (lvb_in && ua->lksb.sb_lvbptr)
@@ -6073,6 +6082,7 @@ int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 		list_move(&lkb->lkb_ownqueue, &ua->proc->unlocking);
 	spin_unlock(&ua->proc->locks_spin);
  out_put:
+	trace_dlm_unlock_end(ls, lkb, flags, error);
 	dlm_put_lkb(lkb);
  out:
 	dlm_unlock_recovery(ls);
@@ -6094,6 +6104,8 @@ int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	if (error)
 		goto out;
 
+	trace_dlm_unlock_start(ls, lkb, flags);
+
 	ua = lkb->lkb_ua;
 	if (ua_tmp->castparam)
 		ua->castparam = ua_tmp->castparam;
@@ -6111,6 +6123,7 @@ int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	if (error == -EBUSY)
 		error = 0;
  out_put:
+	trace_dlm_unlock_end(ls, lkb, flags, error);
 	dlm_put_lkb(lkb);
  out:
 	dlm_unlock_recovery(ls);
@@ -6132,6 +6145,8 @@ int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid)
 	if (error)
 		goto out;
 
+	trace_dlm_unlock_start(ls, lkb, flags);
+
 	ua = lkb->lkb_ua;
 
 	error = set_unlock_args(flags, ua, &args);
@@ -6160,6 +6175,7 @@ int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid)
 	if (error == -EBUSY)
 		error = 0;
  out_put:
+	trace_dlm_unlock_end(ls, lkb, flags, error);
 	dlm_put_lkb(lkb);
  out:
 	dlm_unlock_recovery(ls);

fs/dlm/user.c

@@ -16,6 +16,8 @@
 #include <linux/slab.h>
 #include <linux/sched/signal.h>
 
+#include <trace/events/dlm.h>
+
 #include "dlm_internal.h"
 #include "lockspace.h"
 #include "lock.h"
@@ -882,7 +884,9 @@ static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 		goto try_another;
 	}
 
-	if (cb.flags & DLM_CB_CAST) {
+	if (cb.flags & DLM_CB_BAST) {
+		trace_dlm_bast(lkb->lkb_resource->res_ls, lkb, cb.mode);
+	} else if (cb.flags & DLM_CB_CAST) {
 		new_mode = cb.mode;
 
 		if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
@@ -891,6 +895,7 @@ static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 
 		lkb->lkb_lksb->sb_status = cb.sb_status;
 		lkb->lkb_lksb->sb_flags = cb.sb_flags;
+		trace_dlm_ast(lkb->lkb_resource->res_ls, lkb);
 	}
 
 	rv = copy_result_to_user(lkb->lkb_ua,

include/trace/events/dlm.h

@@ -92,9 +92,10 @@ TRACE_EVENT(dlm_lock_start,
 TRACE_EVENT(dlm_lock_end,
 
 	TP_PROTO(struct dlm_ls *ls, struct dlm_lkb *lkb, void *name,
-		 unsigned int namelen, int mode, __u32 flags, int error),
+		 unsigned int namelen, int mode, __u32 flags, int error,
+		 bool kernel_lock),
 
-	TP_ARGS(ls, lkb, name, namelen, mode, flags, error),
+	TP_ARGS(ls, lkb, name, namelen, mode, flags, error, kernel_lock),
 
 	TP_STRUCT__entry(
 		__field(__u32, ls_id)
@@ -113,6 +114,7 @@ TRACE_EVENT(dlm_lock_end,
 		__entry->lkb_id = lkb->lkb_id;
 		__entry->mode = mode;
 		__entry->flags = flags;
+		__entry->error = error;
 
 		r = lkb->lkb_resource;
 		if (r)
@@ -122,14 +124,14 @@ TRACE_EVENT(dlm_lock_end,
 			memcpy(__get_dynamic_array(res_name), name,
 			       __get_dynamic_array_len(res_name));
 
-		/* return value will be zeroed in those cases by dlm_lock()
-		 * we do it here again to not introduce more overhead if
-		 * trace isn't running and error reflects the return value.
-		 */
-		if (error == -EAGAIN || error == -EDEADLK)
-			__entry->error = 0;
-		else
-			__entry->error = error;
+		if (kernel_lock) {
+			/* return value will be zeroed in those cases by dlm_lock()
+			 * we do it here again to not introduce more overhead if
+			 * trace isn't running and error reflects the return value.
+			 */
+			if (error == -EAGAIN || error == -EDEADLK)
+				__entry->error = 0;
+		}
 
 	),