Commit cf6620ac authored by David Teigland's avatar David Teigland
Browse files

dlm: send reply before bast 



When the lock master processes a successful operation (request,
convert, cancel, or unlock), it will process the effects of the
change before sending the reply for the operation.  The "effects"
of the operation are:

- blocking callbacks (basts) for any newly granted locks
- waiting or converting locks that can now be granted

The cast is queued on the local node when the reply from the lock
master is received.  This means that a lock holder can receive a
bast for a lock mode that is doesn't yet know has been granted.

Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent 7fe2b319

fs/dlm/lock.c

+84 −26
Original line number Diff line number Diff line
@@ -2280,20 +2280,30 @@ static int do_request(struct dlm_rsb *r, struct dlm_lkb *lkb) 
	if (can_be_queued(lkb)) {

		error = -EINPROGRESS;

		add_lkb(r, lkb, DLM_LKSTS_WAITING);

		send_blocking_asts(r, lkb);

		add_timeout(lkb);

		goto out;

	}



	error = -EAGAIN;

	if (force_blocking_asts(lkb))

		send_blocking_asts_all(r, lkb);

	queue_cast(r, lkb, -EAGAIN);



 out:

	return error;

}



static void do_request_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,

			       int error)

{

	switch (error) {

	case -EAGAIN:

		if (force_blocking_asts(lkb))

			send_blocking_asts_all(r, lkb);

		break;

	case -EINPROGRESS:

		send_blocking_asts(r, lkb);

		break;

	}

}



static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)

{

	int error = 0;
@@ -2304,7 +2314,6 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) 
	if (can_be_granted(r, lkb, 1, &deadlk)) {

		grant_lock(r, lkb);

		queue_cast(r, lkb, 0);

		grant_pending_locks(r);

		goto out;

	}
@@ -2334,7 +2343,6 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) 
		if (_can_be_granted(r, lkb, 1)) {

			grant_lock(r, lkb);

			queue_cast(r, lkb, 0);

			grant_pending_locks(r);

			goto out;

		}

		/* else fall through and move to convert queue */
@@ -2344,28 +2352,47 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) 
		error = -EINPROGRESS;

		del_lkb(r, lkb);

		add_lkb(r, lkb, DLM_LKSTS_CONVERT);

		send_blocking_asts(r, lkb);

		add_timeout(lkb);

		goto out;

	}



	error = -EAGAIN;

	if (force_blocking_asts(lkb))

		send_blocking_asts_all(r, lkb);

	queue_cast(r, lkb, -EAGAIN);



 out:

	return error;

}



static void do_convert_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,

			       int error)

{

	switch (error) {

	case 0:

		grant_pending_locks(r);

		/* grant_pending_locks also sends basts */

		break;

	case -EAGAIN:

		if (force_blocking_asts(lkb))

			send_blocking_asts_all(r, lkb);

		break;

	case -EINPROGRESS:

		send_blocking_asts(r, lkb);

		break;

	}

}



static int do_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)

{

	remove_lock(r, lkb);

	queue_cast(r, lkb, -DLM_EUNLOCK);

	grant_pending_locks(r);

	return -DLM_EUNLOCK;

}



static void do_unlock_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,

			      int error)

{

	grant_pending_locks(r);

}



/* returns: 0 did nothing, -DLM_ECANCEL canceled lock */

 

static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb)
@@ -2375,12 +2402,18 @@ static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb) 
	error = revert_lock(r, lkb);

	if (error) {

		queue_cast(r, lkb, -DLM_ECANCEL);

		grant_pending_locks(r);

		return -DLM_ECANCEL;

	}

	return 0;

}



static void do_cancel_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,

			      int error)

{

	if (error)

		grant_pending_locks(r);

}



/*

 * Four stage 3 varieties:

 * _request_lock(), _convert_lock(), _unlock_lock(), _cancel_lock()
@@ -2402,11 +2435,15 @@ static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) 
		goto out;

	}



	if (is_remote(r))

	if (is_remote(r)) {

		/* receive_request() calls do_request() on remote node */

		error = send_request(r, lkb);

	else

	} else {

		error = do_request(r, lkb);

		/* for remote locks the request_reply is sent

		   between do_request and do_request_effects */

		do_request_effects(r, lkb, error);

	}

 out:

	return error;

}
@@ -2417,11 +2454,15 @@ static int _convert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) 
{

	int error;



	if (is_remote(r))

	if (is_remote(r)) {

		/* receive_convert() calls do_convert() on remote node */

		error = send_convert(r, lkb);

	else

	} else {

		error = do_convert(r, lkb);

		/* for remote locks the convert_reply is sent

		   between do_convert and do_convert_effects */

		do_convert_effects(r, lkb, error);

	}



	return error;

}
@@ -2432,11 +2473,15 @@ static int _unlock_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) 
{

	int error;



	if (is_remote(r))

	if (is_remote(r)) {

		/* receive_unlock() calls do_unlock() on remote node */

		error = send_unlock(r, lkb);

	else

	} else {

		error = do_unlock(r, lkb);

		/* for remote locks the unlock_reply is sent

		   between do_unlock and do_unlock_effects */

		do_unlock_effects(r, lkb, error);

	}



	return error;

}
@@ -2447,11 +2492,15 @@ static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) 
{

	int error;



	if (is_remote(r))

	if (is_remote(r)) {

		/* receive_cancel() calls do_cancel() on remote node */

		error = send_cancel(r, lkb);

	else

	} else {

		error = do_cancel(r, lkb);

		/* for remote locks the cancel_reply is sent

		   between do_cancel and do_cancel_effects */

		do_cancel_effects(r, lkb, error);

	}



	return error;

}
@@ -3191,6 +3240,7 @@ static void receive_request(struct dlm_ls *ls, struct dlm_message *ms) 
	attach_lkb(r, lkb);

	error = do_request(r, lkb);

	send_request_reply(r, lkb, error);

	do_request_effects(r, lkb, error);



	unlock_rsb(r);

	put_rsb(r);
@@ -3226,15 +3276,19 @@ static void receive_convert(struct dlm_ls *ls, struct dlm_message *ms) 
		goto out;



	receive_flags(lkb, ms);



	error = receive_convert_args(ls, lkb, ms);

	if (error)

		goto out_reply;

	if (error) {

		send_convert_reply(r, lkb, error);

		goto out;

	}



	reply = !down_conversion(lkb);



	error = do_convert(r, lkb);

 out_reply:

	if (reply)

		send_convert_reply(r, lkb, error);

	do_convert_effects(r, lkb, error);

 out:

	unlock_rsb(r);

	put_rsb(r);
@@ -3266,13 +3320,16 @@ static void receive_unlock(struct dlm_ls *ls, struct dlm_message *ms) 
		goto out;



	receive_flags(lkb, ms);



	error = receive_unlock_args(ls, lkb, ms);

	if (error)

		goto out_reply;

	if (error) {

		send_unlock_reply(r, lkb, error);

		goto out;

	}



	error = do_unlock(r, lkb);

 out_reply:

	send_unlock_reply(r, lkb, error);

	do_unlock_effects(r, lkb, error);

 out:

	unlock_rsb(r);

	put_rsb(r);
@@ -3307,6 +3364,7 @@ static void receive_cancel(struct dlm_ls *ls, struct dlm_message *ms) 


	error = do_cancel(r, lkb);

	send_cancel_reply(r, lkb, error);

	do_cancel_effects(r, lkb, error);

 out:

	unlock_rsb(r);

	put_rsb(r);

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