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Commit 197296ff 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 46385c84

drivers/block/drbd/drbd_int.h

+1 −0
Original line number Diff line number Diff line
@@ -850,6 +850,7 @@ enum { 
	NEW_CUR_UUID,		/* Create new current UUID when thawing IO */

	AL_SUSPENDED,		/* Activity logging is currently suspended. */

	AHEAD_TO_SYNC_SOURCE,   /* Ahead -> SyncSource queued */

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

};



struct drbd_bitmap; /* opaque for drbd_conf */

drivers/block/drbd/drbd_main.c

+13 −0
Original line number Diff line number Diff line
@@ -841,6 +841,13 @@ is_valid_state_transition(struct drbd_conf *mdev, 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, &mdev->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;
@@ -1668,6 +1675,12 @@ 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) {

		clear_bit(STATE_SENT, &mdev->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.

drivers/block/drbd/drbd_nl.c

+1 −1
Original line number Diff line number Diff line
@@ -289,7 +289,7 @@ static int _try_outdate_peer_async(void *data) 
	*/

	spin_lock_irq(&mdev->req_lock);

	ns = mdev->state;

	if (ns.conn < C_WF_REPORT_PARAMS) {

	if (ns.conn < C_WF_REPORT_PARAMS && !test_bit(STATE_SENT, &mdev->flags)) {

		ns.pdsk = nps;

		_drbd_set_state(mdev, ns, CS_VERBOSE, NULL);

	}

drivers/block/drbd/drbd_receiver.c

+9 −1
Original line number Diff line number Diff line
@@ -751,6 +751,7 @@ static int drbd_connect(struct drbd_conf *mdev) 
{

	struct socket *s, *sock, *msock;

	int try, h, ok;

	enum drbd_state_rv rv;



	D_ASSERT(!mdev->data.socket);
@@ -897,6 +898,7 @@ static int drbd_connect(struct drbd_conf *mdev) 


	if (drbd_send_protocol(mdev) == -1)

		return -1;

	set_bit(STATE_SENT, &mdev->flags);

	drbd_send_sync_param(mdev, &mdev->sync_conf);

	drbd_send_sizes(mdev, 0, 0);

	drbd_send_uuids(mdev);
@@ -904,7 +906,13 @@ static int drbd_connect(struct drbd_conf *mdev) 
	clear_bit(USE_DEGR_WFC_T, &mdev->flags);

	clear_bit(RESIZE_PENDING, &mdev->flags);



	if (drbd_request_state(mdev, NS(conn, C_WF_REPORT_PARAMS)) < SS_SUCCESS)

	spin_lock_irq(&mdev->req_lock);

	rv = _drbd_set_state(_NS(mdev, conn, C_WF_REPORT_PARAMS), CS_VERBOSE, NULL);

	if (mdev->state.conn != C_WF_REPORT_PARAMS)

		clear_bit(STATE_SENT, &mdev->flags);

	spin_unlock_irq(&mdev->req_lock);



	if (rv < SS_SUCCESS)

		return 0;



	drbd_thread_start(&mdev->asender);