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Commit a1096a6e authored by Philipp Reisner's avatar Philipp Reisner
Browse files

drbd: Delay/reject other state changes while establishing a connection 



Changes to the role and disk state should be delayed or rejected
while we establish a connection.

This is necessary, since the peer will base its resync decision
on the UUIDs and the state we sent in the drbd_connect() function.

The most prominent example for this race is becoming primary after
sending state and UUIDs and before the state changes to C_WF_CONNECTION.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 27eb13e9

drivers/block/drbd/drbd_int.h

+1 −0
Original line number Diff line number Diff line
@@ -808,6 +808,7 @@ enum { 
	CONN_WD_ST_CHG_FAIL,

	CONN_DRY_RUN,		/* Expect disconnect after resync handshake. */

	CREATE_BARRIER,		/* next P_DATA is preceded by a P_BARRIER */

	STATE_SENT,		/* Do not change state/UUIDs while this is set */

};



struct drbd_tconn {			/* is a resource from the config file */

drivers/block/drbd/drbd_nl.c

+1 −1
Original line number Diff line number Diff line
@@ -502,7 +502,7 @@ bool conn_try_outdate_peer(struct drbd_tconn *tconn) 
	   here, because we might were able to re-establish the connection in the

	   meantime. */

	spin_lock_irq(&tconn->req_lock);

	if (tconn->cstate < C_WF_REPORT_PARAMS)

	if (tconn->cstate < C_WF_REPORT_PARAMS && !test_bit(STATE_SENT, &tconn->flags))

		_conn_request_state(tconn, mask, val, CS_VERBOSE);

	spin_unlock_irq(&tconn->req_lock);

drivers/block/drbd/drbd_receiver.c

+7 −1
Original line number Diff line number Diff line
@@ -848,6 +848,7 @@ static int conn_connect(struct drbd_tconn *tconn) 
	struct net_conf *nc;

	int vnr, timeout, try, h, ok;

	bool discard_my_data;

	enum drbd_state_rv rv;



	if (conn_request_state(tconn, NS(conn, C_WF_CONNECTION), CS_VERBOSE) < SS_SUCCESS)

		return -2;
@@ -1008,6 +1009,8 @@ static int conn_connect(struct drbd_tconn *tconn) 
	if (drbd_send_protocol(tconn) == -EOPNOTSUPP)

		return -1;



	set_bit(STATE_SENT, &tconn->flags);



	rcu_read_lock();

	idr_for_each_entry(&tconn->volumes, mdev, vnr) {

		kref_get(&mdev->kref);
@@ -1024,8 +1027,11 @@ static int conn_connect(struct drbd_tconn *tconn) 
	}

	rcu_read_unlock();



	if (conn_request_state(tconn, NS(conn, C_WF_REPORT_PARAMS), CS_VERBOSE) < SS_SUCCESS)

	rv = conn_request_state(tconn, NS(conn, C_WF_REPORT_PARAMS), CS_VERBOSE);

	if (rv < SS_SUCCESS) {

		clear_bit(STATE_SENT, &tconn->flags);

		return 0;

	}



	drbd_thread_start(&tconn->asender);

drivers/block/drbd/drbd_state.c

+21 −8
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ static int w_after_state_ch(struct drbd_work *w, int unused); 
static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,

			   union drbd_state ns, enum chg_state_flags flags);

static enum drbd_state_rv is_valid_state(struct drbd_conf *, union drbd_state);

static enum drbd_state_rv is_valid_soft_transition(union drbd_state, union drbd_state);

static enum drbd_state_rv is_valid_soft_transition(union drbd_state, union drbd_state, struct drbd_tconn *);

static enum drbd_state_rv is_valid_transition(union drbd_state os, union drbd_state ns);

static union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state ns,

				       enum sanitize_state_warnings *warn);
@@ -267,7 +267,7 @@ _req_st_cond(struct drbd_conf *mdev, union drbd_state mask, 
	if (rv == SS_UNKNOWN_ERROR) {

		rv = is_valid_state(mdev, ns);

		if (rv == SS_SUCCESS) {

			rv = is_valid_soft_transition(os, ns);

			rv = is_valid_soft_transition(os, ns, mdev->tconn);

			if (rv == SS_SUCCESS)

				rv = SS_UNKNOWN_ERROR; /* cont waiting, otherwise fail. */

		}
@@ -313,7 +313,7 @@ drbd_req_state(struct drbd_conf *mdev, union drbd_state mask, 
	if (cl_wide_st_chg(mdev, os, ns)) {

		rv = is_valid_state(mdev, ns);

		if (rv == SS_SUCCESS)

			rv = is_valid_soft_transition(os, ns);

			rv = is_valid_soft_transition(os, ns, mdev->tconn);

		spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);



		if (rv < SS_SUCCESS) {
@@ -569,7 +569,7 @@ is_valid_state(struct drbd_conf *mdev, union drbd_state ns) 
 * @os:		old state.

 */

static enum drbd_state_rv

is_valid_soft_transition(union drbd_state os, union drbd_state ns)

is_valid_soft_transition(union drbd_state os, union drbd_state ns, struct drbd_tconn *tconn)

{

	enum drbd_state_rv rv = SS_SUCCESS;
@@ -595,6 +595,13 @@ is_valid_soft_transition(union drbd_state os, union drbd_state ns) 
	/* if (ns.conn == os.conn && ns.conn == C_WF_REPORT_PARAMS)

	   rv = SS_IN_TRANSIENT_STATE; */



	/* While establishing a connection only allow cstate to change.

	   Delay/refuse role changes, detach attach etc... */

	if (test_bit(STATE_SENT, &tconn->flags) &&

	    !(os.conn == C_WF_REPORT_PARAMS ||

	      (ns.conn == C_WF_REPORT_PARAMS && os.conn == C_WF_CONNECTION)))

		rv = SS_IN_TRANSIENT_STATE;



	if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) && os.conn < C_CONNECTED)

		rv = SS_NEED_CONNECTION;
@@ -927,9 +934,9 @@ __drbd_set_state(struct drbd_conf *mdev, union drbd_state ns, 
			   this happen...*/



			if (is_valid_state(mdev, os) == rv)

				rv = is_valid_soft_transition(os, ns);

				rv = is_valid_soft_transition(os, ns, mdev->tconn);

		} else

			rv = is_valid_soft_transition(os, ns);

			rv = is_valid_soft_transition(os, ns, mdev->tconn);

	}



	if (rv < SS_SUCCESS) {
@@ -1393,6 +1400,12 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os, 
	if (os.disk < D_UP_TO_DATE && os.conn >= C_SYNC_SOURCE && ns.conn == C_CONNECTED)

		drbd_send_state(mdev, ns);



	/* Wake up role changes, that were delayed because of connection establishing */

	if (os.conn == C_WF_REPORT_PARAMS && ns.conn != C_WF_REPORT_PARAMS) {

		if (test_and_clear_bit(STATE_SENT, &mdev->tconn->flags))

			wake_up(&mdev->state_wait);

	}



	/* This triggers bitmap writeout of potentially still unwritten pages

	 * if the resync finished cleanly, or aborted because of peer disk

	 * failure, or because of connection loss.
@@ -1565,9 +1578,9 @@ conn_is_valid_transition(struct drbd_tconn *tconn, union drbd_state mask, union 
			rv = is_valid_state(mdev, ns);

			if (rv < SS_SUCCESS) {

				if (is_valid_state(mdev, os) == rv)

					rv = is_valid_soft_transition(os, ns);

					rv = is_valid_soft_transition(os, ns, tconn);

			} else

				rv = is_valid_soft_transition(os, ns);

				rv = is_valid_soft_transition(os, ns, tconn);

		}

		if (rv < SS_SUCCESS)

			break;