Commit a500c2ef authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Philipp Reisner
Browse files

drbd: struct drbd_request: Introduce a new collision flag 



This flag is set when a processes puts itself to sleep to wait for a
conflicting request to complete.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 9e204cdd

drivers/block/drbd/drbd_receiver.c

+5 −2
Original line number Diff line number Diff line
@@ -1815,6 +1815,7 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 
		first = 1;

		for (;;) {

			struct drbd_interval *i;

			struct drbd_request *req2;

			int have_unacked = 0;

			int have_conflict = 0;

			prepare_to_wait(&mdev->misc_wait, &wait,
@@ -1822,8 +1823,7 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 


			i = drbd_find_overlap(&mdev->write_requests, sector, size);

			if (i) {

				struct drbd_request *req2 =

					container_of(i, struct drbd_request, i);

				req2 = container_of(i, struct drbd_request, i);



				/* only ALERT on first iteration,

				 * we may be woken up early... */
@@ -1869,6 +1869,9 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 
				goto out_interrupted;

			}



			/* Indicate to wake up mdev->misc_wait upon completion.  */

			req2->rq_state |= RQ_COLLISION;



			spin_unlock_irq(&mdev->tconn->req_lock);

			if (first) {

				first = 0;

drivers/block/drbd/drbd_req.c

+3 −39
Original line number Diff line number Diff line
@@ -176,46 +176,10 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev, 
	    req->epoch == mdev->tconn->newest_tle->br_number)

		queue_barrier(mdev);



	/* we need to do the conflict detection stuff,

	 * if the epoch_entries tree is non-empty and

	 * this request has completed on the network */

	if ((s & RQ_NET_DONE) && !RB_EMPTY_ROOT(&mdev->epoch_entries)) {

		const sector_t sector = req->i.sector;

		const int size = req->i.size;

		struct drbd_interval *i;



		/* ASSERT:

		 * there must be no conflicting requests, since

		 * they must have been failed on the spot */



		i = drbd_find_overlap(&mdev->write_requests, sector, size);

		if (i) {

			struct drbd_request *req2 =

				container_of(i, struct drbd_request, i);



			dev_alert(DEV, "LOGIC BUG: completed: %p %llus +%u; "

			      "other: %p %llus +%u\n",

			      req, (unsigned long long)sector, size,

			      i, (unsigned long long)req2->i.sector, req2->i.size);

		}



		/* maybe "wake" those conflicting epoch entries

		 * that wait for this request to finish.

		 *

		 * currently, there can be only _one_ such ee

		 * (well, or some more, which would be pending

		 * P_DISCARD_ACK not yet sent by the asender...),

		 * since we block the receiver thread upon the

		 * first conflict detection, which will wait on

		 * misc_wait.  maybe we want to assert that?

		 *

		 * anyways, if we found one,

		 * we just have to do a wake_up.  */

		i = drbd_find_overlap(&mdev->epoch_entries, sector, size);

		if (i)

	/* Wake up any processes waiting for this request to complete.  */

	if ((s & RQ_NET_DONE) && (s & RQ_COLLISION))

		wake_up(&mdev->misc_wait);

}

}



void complete_master_bio(struct drbd_conf *mdev,

		struct bio_and_error *m)

drivers/block/drbd/drbd_req.h

+7 −0
Original line number Diff line number Diff line
@@ -194,6 +194,12 @@ enum drbd_req_state_bits { 


	/* Should call drbd_al_complete_io() for this request... */

	__RQ_IN_ACT_LOG,



	/*

	 * Set when a processes puts itself to sleep to wait for this request

	 * to complete.

	 */

	__RQ_COLLISION,

};



#define RQ_LOCAL_PENDING   (1UL << __RQ_LOCAL_PENDING)
@@ -214,6 +220,7 @@ enum drbd_req_state_bits { 


#define RQ_WRITE           (1UL << __RQ_WRITE)

#define RQ_IN_ACT_LOG      (1UL << __RQ_IN_ACT_LOG)

#define RQ_COLLISION	   (1UL << __RQ_COLLISION)



/* For waking up the frozen transfer log mod_req() has to return if the request

   should be counted in the epoch object*/