drbd: Force flag for the detach operation

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_main.c

@@ -495,7 +495,7 @@ static int cl_wide_st_chg(struct drbd_conf *mdev,
 		 ((os.role != R_PRIMARY && ns.role == R_PRIMARY) ||
 		  (os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
 		  (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S) ||
-		  (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))) ||
+		  (os.disk != D_FAILED && ns.disk == D_FAILED))) ||
 		(os.conn >= C_CONNECTED && ns.conn == C_DISCONNECTING) ||
 		(os.conn == C_CONNECTED && ns.conn == C_VERIFY_S);
 }

drivers/block/drbd/drbd_nl.c

@@ -1337,17 +1337,32 @@ static int drbd_nl_detach(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
 {
 	enum drbd_ret_code retcode;
 	int ret;
+	struct detach dt = {};
+
+	if (!detach_from_tags(mdev, nlp->tag_list, &dt)) {
+		reply->ret_code = ERR_MANDATORY_TAG;
+		goto out;
+	}
+
+	if (dt.detach_force) {
+		drbd_force_state(mdev, NS(disk, D_FAILED));
+		reply->ret_code = SS_SUCCESS;
+		goto out;
+	}
+
 	drbd_suspend_io(mdev); /* so no-one is stuck in drbd_al_begin_io */
 	retcode = drbd_request_state(mdev, NS(disk, D_FAILED));
 	/* D_FAILED will transition to DISKLESS. */
 	ret = wait_event_interruptible(mdev->misc_wait,
 			mdev->state.disk != D_FAILED);
 	drbd_resume_io(mdev);
+
 	if ((int)retcode == (int)SS_IS_DISKLESS)
 		retcode = SS_NOTHING_TO_DO;
 	if (ret)
 		retcode = ERR_INTR;
 	reply->ret_code = retcode;
+out:
 	return 0;
 }
 

include/linux/drbd_nl.h

@@ -33,7 +33,9 @@ NL_PACKET(disk_conf, 3,
 	NL_BIT(		58,	T_MAY_IGNORE,	no_disk_drain)
 )
 
-NL_PACKET(detach, 4, )
+NL_PACKET(detach, 4,
+	NL_BIT(		88,	T_MANDATORY,	detach_force)
+)
 
 NL_PACKET(net_conf, 5,
 	NL_STRING(	8,	T_MANDATORY,	my_addr,	128)