Commit 7bd000cb authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Jens Axboe
Browse files

drbd: don't forget error completion when "unsuspending" IO 



Possibly sequence of events:
SyncTarget is made Primary, then loses replication link
(only path to good data on SyncSource).

Behavior is then controlled by the on-no-data-accessible policy,
which defaults to OND_IO_ERROR (may be set to OND_SUSPEND_IO).

If OND_IO_ERROR is in fact the current policy, we clear the susp_fen
(IO suspended due to fencing policy) flag, do NOT set the susp_nod
(IO suspended due to no data) flag.

But we forgot to call the IO error completion for all pending,
suspended, requests.

While at it, also add a race check for a theoretically possible
race with a new handshake (network hickup), we may be able to
re-send requests, and can avoid passing IO errors up the stack.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 26a96110

drivers/block/drbd/drbd_nl.c

+32 −16
Original line number Diff line number Diff line
@@ -442,19 +442,17 @@ static enum drbd_fencing_p highest_fencing_policy(struct drbd_connection *connec 
	}

	rcu_read_unlock();



	if (fp == FP_NOT_AVAIL) {

		/* IO Suspending works on the whole resource.

		   Do it only for one device. */

		vnr = 0;

		peer_device = idr_get_next(&connection->peer_devices, &vnr);

		drbd_change_state(peer_device->device, CS_VERBOSE | CS_HARD, NS(susp_fen, 0));

	return fp;

}



	return fp;

static bool resource_is_supended(struct drbd_resource *resource)

{

	return resource->susp || resource->susp_fen || resource->susp_nod;

}



bool conn_try_outdate_peer(struct drbd_connection *connection)

{

	struct drbd_resource * const resource = connection->resource;

	unsigned int connect_cnt;

	union drbd_state mask = { };

	union drbd_state val = { };
@@ -462,21 +460,41 @@ bool conn_try_outdate_peer(struct drbd_connection *connection) 
	char *ex_to_string;

	int r;



	spin_lock_irq(&connection->resource->req_lock);

	spin_lock_irq(&resource->req_lock);

	if (connection->cstate >= C_WF_REPORT_PARAMS) {

		drbd_err(connection, "Expected cstate < C_WF_REPORT_PARAMS\n");

		spin_unlock_irq(&connection->resource->req_lock);

		spin_unlock_irq(&resource->req_lock);

		return false;

	}



	connect_cnt = connection->connect_cnt;

	spin_unlock_irq(&connection->resource->req_lock);

	spin_unlock_irq(&resource->req_lock);



	fp = highest_fencing_policy(connection);

	switch (fp) {

	case FP_NOT_AVAIL:

		drbd_warn(connection, "Not fencing peer, I'm not even Consistent myself.\n");

		goto out;

		spin_lock_irq(&resource->req_lock);

		if (connection->cstate < C_WF_REPORT_PARAMS) {

			_conn_request_state(connection,

					    (union drbd_state) { { .susp_fen = 1 } },

					    (union drbd_state) { { .susp_fen = 0 } },

					    CS_VERBOSE | CS_HARD | CS_DC_SUSP);

			/* We are no longer suspended due to the fencing policy.

			 * We may still be suspended due to the on-no-data-accessible policy.

			 * If that was OND_IO_ERROR, fail pending requests. */

			if (!resource_is_supended(resource))

				_tl_restart(connection, CONNECTION_LOST_WHILE_PENDING);

		}

		/* Else: in case we raced with a connection handshake,

		 * let the handshake figure out if we maybe can RESEND,

		 * and do not resume/fail pending requests here.

		 * Worst case is we stay suspended for now, which may be

		 * resolved by either re-establishing the replication link, or

		 * the next link failure, or eventually the administrator.  */

		spin_unlock_irq(&resource->req_lock);

		return false;



	case FP_DONT_CARE:

		return true;

	default: ;
@@ -529,13 +547,11 @@ bool conn_try_outdate_peer(struct drbd_connection *connection) 
	drbd_info(connection, "fence-peer helper returned %d (%s)\n",

		  (r>>8) & 0xff, ex_to_string);



 out:



	/* Not using

	   conn_request_state(connection, mask, val, CS_VERBOSE);

	   here, because we might were able to re-establish the connection in the

	   meantime. */

	spin_lock_irq(&connection->resource->req_lock);

	spin_lock_irq(&resource->req_lock);

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

		if (connection->connect_cnt != connect_cnt)

			/* In case the connection was established and droped
@@ -544,7 +560,7 @@ bool conn_try_outdate_peer(struct drbd_connection *connection) 
		else

			_conn_request_state(connection, mask, val, CS_VERBOSE);

	}

	spin_unlock_irq(&connection->resource->req_lock);

	spin_unlock_irq(&resource->req_lock);



	return conn_highest_pdsk(connection) <= D_OUTDATED;

}

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