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: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 7896a64..2119d9b 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -172,7 +172,7 @@
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 */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 86fd4c8..f298f9c 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2266,8 +2266,10 @@
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");
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 424dcb3..dbaffca 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -328,8 +328,10 @@
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 @@
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;
diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index a4dbdbc..4025d08 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -227,6 +227,7 @@
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 @@
}
}
}
+ up_read(&drbd_cfg_rwsem);
return 0;
}
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 2b0b0ab..fd38594 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -964,7 +964,10 @@
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 @@
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 @@
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);
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 410900e..02cdff2 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1731,12 +1731,14 @@
spin_unlock_irq(&tconn->data.work.q_lock);
drbd_thread_stop(&tconn->receiver);
+ down_read(&drbd_cfg_rwsem);
idr_for_each_entry(&tconn->volumes, mdev, vnr) {
D_ASSERT(mdev->state.disk == D_DISKLESS && mdev->state.conn == C_STANDALONE);
/* _drbd_set_state only uses stop_nowait.
* wait here for the exiting receiver. */
drbd_mdev_cleanup(mdev);
}
+ up_read(&drbd_cfg_rwsem);
clear_bit(OBJECT_DYING, &tconn->flags);
clear_bit(CONFIG_PENDING, &tconn->flags);
wake_up(&tconn->ping_wait);