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Commit d3fcb490 authored by Philipp Reisner's avatar Philipp Reisner
Browse files

drbd: protect all idr accesses that might sleep with drbd_cfg_rwsem 



With this commit the locking for all accesses to IDRs is complete:

 * Non sleeping read accesses are protected by RCU
 * sleeping read accesses are protocted by a read lock on drbd_cfg_rwsem
 * accesses that add anything are protected by a write lock
 * accesses that remove an object are protoected by a write lock
   and a call to synchronize_rcu() after it is removed from the IDR
   and before the object is actually free()ed.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent ef356262

drivers/block/drbd/drbd_int.h

+1 −1
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ extern struct ratelimit_state drbd_ratelimit_state; 
extern struct idr minors;

extern struct list_head drbd_tconns;

extern struct rw_semaphore drbd_cfg_rwsem;

/* drbd_cfg_rwsem protects: drbd_tconns list,

/* drbd_cfg_rwsem protects: drbd_tconns list, minors idr, tconn->volumes idr 

   note: non sleeping iterations over the idrs are protoected by RCU */



/* on the wire */

drivers/block/drbd/drbd_main.c

+2 −0
Original line number Diff line number Diff line
@@ -2266,8 +2266,10 @@ static void drbd_cleanup(void) 


	drbd_genl_unregister();



	down_write(&drbd_cfg_rwsem);

	idr_for_each_entry(&minors, mdev, i)

		drbd_delete_device(mdev);

	up_write(&drbd_cfg_rwsem);



	drbd_destroy_mempools();

	unregister_blkdev(DRBD_MAJOR, "drbd");

drivers/block/drbd/drbd_nl.c

+4 −0
Original line number Diff line number Diff line
@@ -328,8 +328,10 @@ static void conn_md_sync(struct drbd_tconn *tconn) 
	struct drbd_conf *mdev;

	int vnr;



	down_read(&drbd_cfg_rwsem);

	idr_for_each_entry(&tconn->volumes, mdev, vnr)

		drbd_md_sync(mdev);

	up_read(&drbd_cfg_rwsem);

}



int conn_khelper(struct drbd_tconn *tconn, char *cmd)
@@ -2865,7 +2867,9 @@ int drbd_adm_add_minor(struct sk_buff *skb, struct genl_info *info) 
		goto out;

	}



	down_write(&drbd_cfg_rwsem);

	retcode = conn_new_minor(adm_ctx.tconn, dh->minor, adm_ctx.volume);

	up_write(&drbd_cfg_rwsem);

out:

	drbd_adm_finish(info, retcode);

	return 0;

drivers/block/drbd/drbd_proc.c

+2 −0
Original line number Diff line number Diff line
@@ -227,6 +227,7 @@ static int drbd_seq_show(struct seq_file *seq, void *v) 
	 oos .. known out-of-sync kB

	*/



	down_read(&drbd_cfg_rwsem);

	idr_for_each_entry(&minors, mdev, i) {

		if (prev_i != i - 1)

			seq_printf(seq, "\n");
@@ -293,6 +294,7 @@ static int drbd_seq_show(struct seq_file *seq, void *v) 
			}

		}

	}

	up_read(&drbd_cfg_rwsem);



	return 0;

}

drivers/block/drbd/drbd_receiver.c

+11 −2
Original line number Diff line number Diff line
@@ -964,7 +964,10 @@ static int drbd_connect(struct drbd_tconn *tconn) 
	if (drbd_send_protocol(tconn) == -EOPNOTSUPP)

		return -1;



	return !idr_for_each(&tconn->volumes, drbd_connected, tconn);

	down_read(&drbd_cfg_rwsem);

	h = !idr_for_each(&tconn->volumes, drbd_connected, tconn);

	up_read(&drbd_cfg_rwsem);

	return h;



out_release_sockets:

	if (tconn->data.socket) {
@@ -4084,7 +4087,9 @@ static void drbd_disconnect(struct drbd_tconn *tconn) 
	drbd_thread_stop(&tconn->asender);

	drbd_free_sock(tconn);



	down_read(&drbd_cfg_rwsem);

	idr_for_each(&tconn->volumes, drbd_disconnected, tconn);

	up_read(&drbd_cfg_rwsem);

	conn_info(tconn, "Connection closed\n");



	if (conn_highest_role(tconn) == R_PRIMARY && conn_highest_pdsk(tconn) >= D_UNKNOWN)
@@ -4821,10 +4826,14 @@ static int tconn_finish_peer_reqs(struct drbd_tconn *tconn) 
	do {

		clear_bit(SIGNAL_ASENDER, &tconn->flags);

		flush_signals(current);

		down_read(&drbd_cfg_rwsem);

		idr_for_each_entry(&tconn->volumes, mdev, i) {

			if (drbd_finish_peer_reqs(mdev))

			if (drbd_finish_peer_reqs(mdev)) {

				up_read(&drbd_cfg_rwsem);

				return 1; /* error */

			}

		}

		up_read(&drbd_cfg_rwsem);

		set_bit(SIGNAL_ASENDER, &tconn->flags);



		spin_lock_irq(&tconn->req_lock);