Commit 5e472264 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Philipp Reisner
Browse files

drbd: _req_conflicts(): Get rid of the epoch_entries tree 



Instead of keeping a separate tree for local and remote write requests
for finding requests and for conflict detection, use the same tree for
both purposes.  Introduce a flag to allow distinguishing the two
possible types of entries in this tree.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 53840641

drivers/block/drbd/drbd_int.h

+0 −3
Original line number Diff line number Diff line
@@ -1045,9 +1045,6 @@ struct drbd_conf { 
	struct list_head read_ee;   /* IO in progress (any read) */

	struct list_head net_ee;    /* zero-copy network send in progress */



	/* Interval tree of pending remote write requests (struct drbd_epoch_entry) */

	struct rb_root epoch_entries;



	/* this one is protected by ee_lock, single thread */

	struct drbd_epoch_entry *last_write_w_barrier;

drivers/block/drbd/drbd_interval.h

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ struct drbd_interval { 
	sector_t sector;	/* start sector of the interval */

	unsigned int size;	/* size in bytes */

	sector_t end;		/* highest interval end in subtree */

	int local:1		/* local or remote request? */;

	int waiting:1;

};

drivers/block/drbd/drbd_main.c

+0 −1
Original line number Diff line number Diff line
@@ -3450,7 +3450,6 @@ struct drbd_conf *drbd_new_device(unsigned int minor) 
		goto out_no_tl;

	mdev->read_requests = RB_ROOT;

	mdev->write_requests = RB_ROOT;

	mdev->epoch_entries = RB_ROOT;



	mdev->current_epoch = kzalloc(sizeof(struct drbd_epoch), GFP_KERNEL);

	if (!mdev->current_epoch)

drivers/block/drbd/drbd_receiver.c

+16 −17
Original line number Diff line number Diff line
@@ -336,6 +336,7 @@ struct drbd_epoch_entry *drbd_alloc_ee(struct drbd_conf *mdev, 
	drbd_clear_interval(&e->i);

	e->i.size = data_size;

	e->i.sector = sector;

	e->i.local = false;

	e->i.waiting = false;



	e->epoch = NULL;
@@ -1508,7 +1509,7 @@ find_request(struct drbd_conf *mdev, struct rb_root *root, u64 id, 


	/* Request object according to our peer */

	req = (struct drbd_request *)(unsigned long)id;

	if (drbd_contains_interval(root, sector, &req->i))

	if (drbd_contains_interval(root, sector, &req->i) && req->i.local)

		return req;

	if (!missing_ok) {

		dev_err(DEV, "%s: failed to find request %lu, sector %llus\n", func,
@@ -1788,17 +1789,12 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 
		/* conflict detection and handling:

		 * 1. wait on the sequence number,

		 *    in case this data packet overtook ACK packets.

		 * 2. check our interval trees for conflicting requests:

		 *    we only need to check the write_requests tree; the

		 *    epoch_entries tree cannot contain any overlaps because

		 *    they were already eliminated on the submitting node.

		 * 2. check for conflicting write requests.

		 *

		 * Note: for two_primaries, we are protocol C,

		 * so there cannot be any request that is DONE

		 * but still on the transfer log.

		 *

		 * unconditionally add to the epoch_entries tree.

		 *

		 * if no conflicting request is found:

		 *    submit.

		 *
@@ -1823,12 +1819,9 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 


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



		drbd_insert_interval(&mdev->epoch_entries, &e->i);



		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,
@@ -1836,18 +1829,23 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 


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

			if (i) {

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



				/* only ALERT on first iteration,

				 * we may be woken up early... */

				if (first)

					dev_alert(DEV, "%s[%u] Concurrent local write detected!"

					dev_alert(DEV, "%s[%u] Concurrent %s write detected!"

					      "	new: %llus +%u; pending: %llus +%u\n",

					      current->comm, current->pid,

					      i->local ? "local" : "remote",

					      (unsigned long long)sector, size,

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

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



				if (i->local) {

					struct drbd_request *req2;



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

					if (req2->rq_state & RQ_NET_PENDING)

						++have_unacked;

				}

				++have_conflict;

			}

			if (!have_conflict)
@@ -1873,7 +1871,6 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 
			}



			if (signal_pending(current)) {

				drbd_remove_epoch_entry_interval(mdev, e);

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

				finish_wait(&mdev->misc_wait, &wait);

				goto out_interrupted;
@@ -1896,6 +1893,8 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd, 
			spin_lock_irq(&mdev->tconn->req_lock);

		}

		finish_wait(&mdev->misc_wait, &wait);



		drbd_insert_interval(&mdev->write_requests, &e->i);

	}



	list_add(&e->w.list, &mdev->active_ee);

drivers/block/drbd/drbd_req.c

+4 −24
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ static struct drbd_request *drbd_req_new(struct drbd_conf *mdev, 
	drbd_clear_interval(&req->i);

	req->i.sector     = bio_src->bi_sector;

	req->i.size      = bio_src->bi_size;

	req->i.local = true;

	req->i.waiting = false;



	INIT_LIST_HEAD(&req->tl_requests);
@@ -317,8 +318,6 @@ static void _req_may_be_done_not_susp(struct drbd_request *req, struct bio_and_e 
 * to happen, but this is the rationale why we also have to check for

 * conflicting requests with local origin, and why we have to do so regardless

 * of whether we allowed multiple primaries.

 *

 * In case we only have one primary, the epoch_entries tree is empty.

 */

static int _req_conflicts(struct drbd_request *req)

{
@@ -334,34 +333,15 @@ static int _req_conflicts(struct drbd_request *req) 


	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, "%s[%u] Concurrent local write detected! "

		      "[DISCARD L] new: %llus +%u; "

		      "pending: %llus +%u\n",

		      current->comm, current->pid,

		      (unsigned long long)sector, size,

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

		goto out_conflict;

	}



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

		/* check for overlapping requests with remote origin */

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

		if (i) {

			struct drbd_epoch_entry *e =

				container_of(i, struct drbd_epoch_entry, i);



			dev_alert(DEV, "%s[%u] Concurrent remote write detected!"

		dev_alert(DEV, "%s[%u] Concurrent %s write detected! "

		      "[DISCARD L] new: %llus +%u; "

		      "pending: %llus +%u\n",

		      current->comm, current->pid,

		      i->local ? "local" : "remote",

		      (unsigned long long)sector, size,

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

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

		goto out_conflict;

	}

	}



	/* this is like it should be, and what we expected.

	 * our users do behave after all... */