drbd: Do not try to free tl_hash in drbd_disconnect() when IO is suspended

We may not free tl_hash when IO is suspended, since we can not wait
until ap_bio_cnt reaches zero.

We can do this after susp reched 0, since then tl_clear was called
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -1493,6 +1493,7 @@ extern void _drbd_wait_ee_list_empty(struct drbd_conf *mdev,
 extern void drbd_set_recv_tcq(struct drbd_conf *mdev, int tcq_enabled);
 extern void _drbd_clear_done_ee(struct drbd_conf *mdev, struct list_head *to_be_freed);
 extern void drbd_flush_workqueue(struct drbd_conf *mdev);
+extern void drbd_free_tl_hash(struct drbd_conf *mdev);
 
 /* yes, there is kernel_setsockopt, but only since 2.6.18. we don't need to
  * mess with get_fs/set_fs, we know we are KERNEL_DS always. */

drivers/block/drbd/drbd_main.c

@@ -1409,6 +1409,10 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 	    (os.user_isp && !ns.user_isp))
 		resume_next_sg(mdev);
 
+	/* free tl_hash if we Got thawed and are C_STANDALONE */
+	if (ns.conn == C_STANDALONE && ns.susp == 0 && mdev->tl_hash)
+		drbd_free_tl_hash(mdev);
+
 	/* Upon network connection, we need to start the receiver */
 	if (os.conn == C_STANDALONE && ns.conn == C_UNCONNECTED)
 		drbd_thread_start(&mdev->receiver);

drivers/block/drbd/drbd_nl.c

@@ -1391,6 +1391,7 @@ static int drbd_nl_net_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
 		}
 	}
 
+	drbd_flush_workqueue(mdev);
 	spin_lock_irq(&mdev->req_lock);
 	if (mdev->net_conf != NULL) {
 		retcode = ERR_NET_CONFIGURED;
@@ -1429,10 +1430,9 @@ static int drbd_nl_net_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
 	mdev->int_dig_out=int_dig_out;
 	mdev->int_dig_in=int_dig_in;
 	mdev->int_dig_vv=int_dig_vv;
+	retcode = _drbd_set_state(_NS(mdev, conn, C_UNCONNECTED), CS_VERBOSE, NULL);
 	spin_unlock_irq(&mdev->req_lock);
 
-	retcode = _drbd_request_state(mdev, NS(conn, C_UNCONNECTED), CS_VERBOSE);
-
 	kobject_uevent(&disk_to_dev(mdev->vdisk)->kobj, KOBJ_CHANGE);
 	reply->ret_code = retcode;
 	drbd_reconfig_done(mdev);

drivers/block/drbd/drbd_receiver.c

@@ -3691,6 +3691,36 @@ void drbd_flush_workqueue(struct drbd_conf *mdev)
 	wait_for_completion(&barr.done);
 }
 
+void drbd_free_tl_hash(struct drbd_conf *mdev)
+{
+	struct hlist_head *h;
+
+	spin_lock_irq(&mdev->req_lock);
+
+	if (!mdev->tl_hash || mdev->state.conn != C_STANDALONE) {
+		spin_unlock_irq(&mdev->req_lock);
+		return;
+	}
+	/* paranoia code */
+	for (h = mdev->ee_hash; h < mdev->ee_hash + mdev->ee_hash_s; h++)
+		if (h->first)
+			dev_err(DEV, "ASSERT FAILED ee_hash[%u].first == %p, expected NULL\n",
+				(int)(h - mdev->ee_hash), h->first);
+	kfree(mdev->ee_hash);
+	mdev->ee_hash = NULL;
+	mdev->ee_hash_s = 0;
+
+	/* paranoia code */
+	for (h = mdev->tl_hash; h < mdev->tl_hash + mdev->tl_hash_s; h++)
+		if (h->first)
+			dev_err(DEV, "ASSERT FAILED tl_hash[%u] == %p, expected NULL\n",
+				(int)(h - mdev->tl_hash), h->first);
+	kfree(mdev->tl_hash);
+	mdev->tl_hash = NULL;
+	mdev->tl_hash_s = 0;
+	spin_unlock_irq(&mdev->req_lock);
+}
+
 static void drbd_disconnect(struct drbd_conf *mdev)
 {
 	enum drbd_fencing_p fp;
@@ -3774,32 +3804,14 @@ static void drbd_disconnect(struct drbd_conf *mdev)
 	spin_unlock_irq(&mdev->req_lock);
 
 	if (os.conn == C_DISCONNECTING) {
-		struct hlist_head *h;
 		wait_event(mdev->net_cnt_wait, atomic_read(&mdev->net_cnt) == 0);
 
-		/* we must not free the tl_hash
-		 * while application io is still on the fly */
-		wait_event(mdev->misc_wait, atomic_read(&mdev->ap_bio_cnt) == 0);
-
-		spin_lock_irq(&mdev->req_lock);
-		/* paranoia code */
-		for (h = mdev->ee_hash; h < mdev->ee_hash + mdev->ee_hash_s; h++)
-			if (h->first)
-				dev_err(DEV, "ASSERT FAILED ee_hash[%u].first == %p, expected NULL\n",
-						(int)(h - mdev->ee_hash), h->first);
-		kfree(mdev->ee_hash);
-		mdev->ee_hash = NULL;
-		mdev->ee_hash_s = 0;
-
-		/* paranoia code */
-		for (h = mdev->tl_hash; h < mdev->tl_hash + mdev->tl_hash_s; h++)
-			if (h->first)
-				dev_err(DEV, "ASSERT FAILED tl_hash[%u] == %p, expected NULL\n",
-						(int)(h - mdev->tl_hash), h->first);
-		kfree(mdev->tl_hash);
-		mdev->tl_hash = NULL;
-		mdev->tl_hash_s = 0;
-		spin_unlock_irq(&mdev->req_lock);
+		if (!mdev->state.susp) {
+			/* we must not free the tl_hash
+			 * while application io is still on the fly */
+			wait_event(mdev->misc_wait, !atomic_read(&mdev->ap_bio_cnt));
+			drbd_free_tl_hash(mdev);
+		}
 
 		crypto_free_hash(mdev->cram_hmac_tfm);
 		mdev->cram_hmac_tfm = NULL;