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 (file)
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -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 */

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 86fd4c8..f298f9c 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -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");

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 424dcb3..dbaffca 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -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;

diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index a4dbdbc..4025d08 100644 (file)
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -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;
 }

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 2b0b0ab..fd38594 100644 (file)
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -964,7 +964,10 @@ retry:
        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);

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 410900e..02cdff2 100644 (file)
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1731,12 +1731,14 @@ int drbd_worker(struct drbd_thread *thi)
        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);