drbd: Fixed logging of old connection state

During a disconnect the oc variable in _conn_request_state()
could become outdated. Determin the common old state after
sleeping.
While at it, I implemented that for all parts of the state
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_state.c

@@ -1377,42 +1377,100 @@ static void print_conn_state_change(struct drbd_tconn *tconn, enum drbd_conns oc
 	conn_info(tconn, "%s\n", pb);
 }
 
-struct _is_valid_itr_params {
-	enum drbd_conns oc;
-	enum {
-		OC_UNINITIALIZED,
-		OC_CONSISTENT,
-		OC_INCONSISTENT,
-	} oc_state;
-};
+enum sp_state {
+	OC_UNINITIALIZED,
+	OC_CONSISTENT,
+	OC_INCONSISTENT,
+} oc_state;
+
+static void common_state_part(enum sp_state *sps, int *sp, int nsp)
+{
+	switch (*sps) {
+	case OC_UNINITIALIZED:
+		*sp = nsp;
+		*sps = OC_CONSISTENT;
+		break;
+	case OC_CONSISTENT:
+		if (*sp != nsp)
+			*sps = OC_INCONSISTENT;
+		break;
+	case OC_INCONSISTENT:
+		break;
+	}
+}
+
+void conn_old_common_state(struct drbd_tconn *tconn, union drbd_state *pcs, union drbd_state *pmask)
+{
+	union drbd_state css = {}; /* common state state */
+	union drbd_state os, cs = {}; /* old_state, common_state */
+	union drbd_state mask = {};
+	enum sp_state sps;       /* state part state */
+	int sp;                  /* state part */
+	struct drbd_conf *mdev;
+	int vnr;
+
+	idr_for_each_entry(&tconn->volumes, mdev, vnr) {
+		os = mdev->state;
+
+		sps = css.role;
+		sp = cs.role;
+		common_state_part(&sps, &sp, os.role);
+		css.role = sps;
+		cs.role = sp;
+
+		sps = css.peer;
+		sp = cs.peer;
+		common_state_part(&sps, &sp, os.peer);
+		css.peer = sps;
+		cs.peer = sp;
+
+		sps = css.conn;
+		sp = cs.conn;
+		common_state_part(&sps, &sp, os.conn);
+		css.conn = sps;
+		cs.conn = sp;
+
+		sps = css.disk;
+		sp = cs.disk;
+		common_state_part(&sps, &sp, os.disk);
+		css.disk = sps;
+		cs.disk = sp;
+
+		sps = css.pdsk;
+		sp = cs.pdsk;
+		common_state_part(&sps, &sp, os.pdsk);
+		css.pdsk = sps;
+		cs.pdsk = sp;
+	}
+
+	if (css.role == OC_CONSISTENT)
+		mask.role = R_MASK;
+	if (css.peer == OC_CONSISTENT)
+		mask.peer = R_MASK;
+	if (css.conn == OC_CONSISTENT)
+		mask.conn = C_MASK;
+	if (css.disk == OC_CONSISTENT)
+		mask.disk = D_MASK;
+	if (css.pdsk == OC_CONSISTENT)
+		mask.pdsk = D_MASK;
+
+	*pcs = cs;
+	*pmask = mask;
+}
 
 static enum drbd_state_rv
 conn_is_valid_transition(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state val,
-			 enum chg_state_flags flags, struct _is_valid_itr_params *params)
+			 enum chg_state_flags flags)
 {
 	enum drbd_state_rv rv = SS_SUCCESS;
 	union drbd_state ns, os;
 	struct drbd_conf *mdev;
 	int vnr;
 
-	params->oc_state = OC_UNINITIALIZED;
 	idr_for_each_entry(&tconn->volumes, mdev, vnr) {
 		os = mdev->state;
 		ns = sanitize_state(mdev, apply_mask_val(os, mask, val), NULL);
 
-		switch (params->oc_state) {
-		case OC_UNINITIALIZED:
-			params->oc = os.conn;
-			params->oc_state = OC_CONSISTENT;
-			break;
-		case OC_CONSISTENT:
-			if (params->oc != os.conn)
-				params->oc_state = OC_INCONSISTENT;
-			break;
-		case OC_INCONSISTENT:
-			break;
-		}
-
 		if (ns.i == os.i)
 			continue;
 
@@ -1471,7 +1529,6 @@ conn_set_state(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state
 static enum drbd_state_rv
 _conn_rq_cond(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state val)
 {
-	struct _is_valid_itr_params params;
 	enum drbd_state_rv rv;
 
 	if (test_and_clear_bit(CONN_WD_ST_CHG_OKAY, &tconn->flags))
@@ -1484,7 +1541,7 @@ _conn_rq_cond(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state
 	rv = tconn->cstate != C_WF_REPORT_PARAMS ? SS_CW_NO_NEED : SS_UNKNOWN_ERROR;
 
 	if (rv == SS_UNKNOWN_ERROR)
-		rv = conn_is_valid_transition(tconn, mask, val, CS_NO_CSTATE_CHG, &params);
+		rv = conn_is_valid_transition(tconn, mask, val, CS_NO_CSTATE_CHG);
 
 	if (rv == SS_SUCCESS)
 		rv = SS_UNKNOWN_ERROR; /* cont waiting, otherwise fail. */
@@ -1524,16 +1581,15 @@ _conn_request_state(struct drbd_tconn *tconn, union drbd_state mask, union drbd_
 		    enum chg_state_flags flags)
 {
 	enum drbd_state_rv rv = SS_SUCCESS;
-	struct _is_valid_itr_params params;
 	struct after_conn_state_chg_work *acscw;
 	enum drbd_conns oc = tconn->cstate;
-	union drbd_state ms;
+	union drbd_state ms, os_val, os_mask;
 
 	rv = is_valid_conn_transition(oc, val.conn);
 	if (rv < SS_SUCCESS)
 		goto abort;
 
-	rv = conn_is_valid_transition(tconn, mask, val, flags, &params);
+	rv = conn_is_valid_transition(tconn, mask, val, flags);
 	if (rv < SS_SUCCESS)
 		goto abort;
 
@@ -1544,8 +1600,9 @@ _conn_request_state(struct drbd_tconn *tconn, union drbd_state mask, union drbd_
 			goto abort;
 	}
 
-	if (params.oc_state == OC_CONSISTENT) {
-		oc = params.oc;
+	conn_old_common_state(tconn, &os_val, &os_mask);
+	if (os_mask.conn == C_MASK) {
+		oc = os_val.conn;
 		print_conn_state_change(tconn, oc, val.conn);
 		flags |= CS_NO_CSTATE_CHG;
 	}