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Commit d93f6302 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Philipp Reisner
Browse files

drbd: Fix a potential write ordering issue on SyncTarget nodes 



Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 81f44862

drivers/block/drbd/drbd_receiver.c

+30 −0
Original line number Original line Diff line number Diff line
@@ -1911,6 +1911,33 @@ static void update_peer_seq(struct drbd_conf *mdev, unsigned int peer_seq) 
	}

	}

}

}





static inline int overlaps(sector_t s1, int l1, sector_t s2, int l2)

{

	return !((s1 + (l1>>9) <= s2) || (s1 >= s2 + (l2>>9)));

}



/* maybe change sync_ee into interval trees as well? */

static bool overlaping_resync_write(struct drbd_conf *mdev, struct drbd_peer_request *peer_req)

{

	struct drbd_peer_request *rs_req;

	bool rv = 0;



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

	list_for_each_entry(rs_req, &mdev->sync_ee, w.list) {

		if (overlaps(peer_req->i.sector, peer_req->i.size,

			     rs_req->i.sector, rs_req->i.size)) {

			rv = 1;

			break;

		}

	}

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



	if (rv)

		dev_warn(DEV, "WARN: Avoiding concurrent data/resync write to single sector.\n");



	return rv;

}



/* Called from receive_Data.

/* Called from receive_Data.

 * Synchronize packets on sock with packets on msock.

 * Synchronize packets on sock with packets on msock.

 *

 *
@@ -2192,6 +2219,9 @@ static int receive_Data(struct drbd_tconn *tconn, struct packet_info *pi) 
	list_add(&peer_req->w.list, &mdev->active_ee);

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

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

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





	if (mdev->state.conn == C_SYNC_TARGET)

		wait_event(mdev->ee_wait, !overlaping_resync_write(mdev, peer_req));



	if (mdev->tconn->agreed_pro_version < 100) {

	if (mdev->tconn->agreed_pro_version < 100) {

		rcu_read_lock();

		rcu_read_lock();

		switch (rcu_dereference(mdev->tconn->net_conf)->wire_protocol) {

		switch (rcu_dereference(mdev->tconn->net_conf)->wire_protocol) {