Commit de696716 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Philipp Reisner
Browse files

drbd: Use interval tree for overlapping write request detection 



Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent ace652ac

drivers/block/drbd/drbd_int.h

+3 −0
Original line number Diff line number Diff line
@@ -1019,6 +1019,9 @@ struct drbd_conf { 
	struct hlist_head *tl_hash;

	unsigned int tl_hash_s;



	/* Interval tree of pending local write requests */

	struct rb_root write_requests;



	/* blocks to resync in this run [unit BM_BLOCK_SIZE] */

	unsigned long rs_total;

	/* number of resync blocks that failed in this run */

drivers/block/drbd/drbd_main.c

+1 −0
Original line number Diff line number Diff line
@@ -3473,6 +3473,7 @@ struct drbd_conf *drbd_new_device(unsigned int minor) 
	/* no need to lock access, we are still initializing this minor device. */

	if (!tl_init(mdev))

		goto out_no_tl;

	mdev->write_requests = RB_ROOT;



	mdev->app_reads_hash = kzalloc(APP_R_HSIZE*sizeof(void *), GFP_KERNEL);

	if (!mdev->app_reads_hash)

drivers/block/drbd/drbd_receiver.c

+18 −20
Original line number Diff line number Diff line
@@ -1733,9 +1733,6 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned 
		const int size = e->size;

		const int discard = test_bit(DISCARD_CONCURRENT, &mdev->flags);

		DEFINE_WAIT(wait);

		struct drbd_request *i;

		struct hlist_node *n;

		struct hlist_head *slot;

		int first;



		D_ASSERT(mdev->net_conf->wire_protocol == DRBD_PROT_C);
@@ -1783,16 +1780,19 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned 


		hlist_add_head(&e->collision, ee_hash_slot(mdev, sector));



#define OVERLAPS overlaps(i->i.sector, i->i.size, sector, size)

		slot = tl_hash_slot(mdev, sector);

		first = 1;

		for (;;) {

			struct drbd_interval *i;

			int have_unacked = 0;

			int have_conflict = 0;

			prepare_to_wait(&mdev->misc_wait, &wait,

				TASK_INTERRUPTIBLE);

			hlist_for_each_entry(i, n, slot, collision) {

				if (OVERLAPS) {



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

			if (i) {

				struct drbd_request *req2 =

					container_of(i, struct drbd_request, i);



				/* only ALERT on first iteration,

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

				if (first)
@@ -1800,13 +1800,11 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned 
					      "	new: %llus +%u; pending: %llus +%u\n",

					      current->comm, current->pid,

					      (unsigned long long)sector, size,

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

					if (i->rq_state & RQ_NET_PENDING)

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

				if (req2->rq_state & RQ_NET_PENDING)

					++have_unacked;

				++have_conflict;

			}

			}

#undef OVERLAPS

			if (!have_conflict)

				break;

drivers/block/drbd/drbd_req.c

+29 −27
Original line number Diff line number Diff line
@@ -135,7 +135,6 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev, 
	struct drbd_request *req)

{

	const unsigned long s = req->rq_state;

	struct drbd_request *i;

	struct drbd_epoch_entry *e;

	struct hlist_node *n;

	struct hlist_head *slot;
@@ -157,19 +156,21 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev, 
	if ((s & RQ_NET_DONE) && mdev->ee_hash != NULL) {

		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 */

#define OVERLAPS overlaps(sector, size, i->i.sector, i->i.size)

		slot = tl_hash_slot(mdev, sector);

		hlist_for_each_entry(i, n, slot, collision) {

			if (OVERLAPS) {



		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)i->i.sector, i->i.size);

			}

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

		}



		/* maybe "wake" those conflicting epoch entries
@@ -184,7 +185,6 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev, 
		 *

		 * anyways, if we found one,

		 * we just have to do a wake_up.  */

#undef OVERLAPS

#define OVERLAPS overlaps(sector, size, e->sector, e->size)

		slot = ee_hash_slot(mdev, req->i.sector);

		hlist_for_each_entry(e, n, slot, collision) {
@@ -260,9 +260,11 @@ void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m) 


		/* remove the request from the conflict detection

		 * respective block_id verification hash */

		if (!hlist_unhashed(&req->collision))

		if (!hlist_unhashed(&req->collision)) {

			hlist_del(&req->collision);

		else

			if (!drbd_interval_empty(&req->i))

				drbd_remove_interval(&mdev->write_requests, &req->i);

		} else

			D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);



		/* for writes we need to do some extra housekeeping */
@@ -324,7 +326,7 @@ static int _req_conflicts(struct drbd_request *req) 
	struct drbd_conf *mdev = req->mdev;

	const sector_t sector = req->i.sector;

	const int size = req->i.size;

	struct drbd_request *i;

	struct drbd_interval *i;

	struct drbd_epoch_entry *e;

	struct hlist_node *n;

	struct hlist_head *slot;
@@ -339,24 +341,23 @@ static int _req_conflicts(struct drbd_request *req) 
		goto out_no_conflict;

	BUG_ON(mdev->tl_hash == NULL);



#define OVERLAPS overlaps(i->i.sector, i->i.size, sector, size)

	slot = tl_hash_slot(mdev, sector);

	hlist_for_each_entry(i, n, slot, collision) {

		if (OVERLAPS) {

	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)i->i.sector, i->i.size);

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

		goto out_conflict;

	}

	}



	if (mdev->ee_hash_s) {

		/* now, check for overlapping requests with remote origin */

		BUG_ON(mdev->ee_hash == NULL);

#undef OVERLAPS

#define OVERLAPS overlaps(e->sector, e->size, sector, size)

		slot = ee_hash_slot(mdev, sector);

		hlist_for_each_entry(e, n, slot, collision) {
@@ -509,6 +510,7 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what, 


		hlist_add_head(&req->collision, tl_hash_slot(mdev, req->i.sector));

		/* corresponding hlist_del is in _req_may_be_done() */

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



		/* NOTE

		 * In case the req ended up on the transfer log before being

drivers/block/drbd/drbd_req.h

+1 −0
Original line number Diff line number Diff line
@@ -275,6 +275,7 @@ static inline struct drbd_request *drbd_req_new(struct drbd_conf *mdev, 
		req->i.sector     = bio_src->bi_sector;

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

		INIT_HLIST_NODE(&req->collision);

		drbd_clear_interval(&req->i);

		INIT_LIST_HEAD(&req->tl_requests);

		INIT_LIST_HEAD(&req->w.list);

	}