5 files changed, 30 insertions, 25 deletions

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index b5730e17b455..656624314f0d 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -315,24 +315,32 @@ void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m)
 }
 
 /* still holds resource->req_lock */
-static int drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
+static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
 {
 	struct drbd_device *device = req->device;
 	D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED));
 
+	if (!put)
+		return;
+
 	if (!atomic_sub_and_test(put, &req->completion_ref))
-		return 0;
+		return;
 
 	drbd_req_complete(req, m);
 
+	/* local completion may still come in later,
+	 * we need to keep the req object around. */
+	if (req->rq_state & RQ_LOCAL_ABORTED)
+		return;
+
 	if (req->rq_state & RQ_POSTPONED) {
 		/* don't destroy the req object just yet,
 		 * but queue it for retry */
 		drbd_restart_request(req);
-		return 0;
+		return;
 	}
 
-	return 1;
+	kref_put(&req->kref, drbd_req_destroy);
 }
 
 static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req)
@@ -519,12 +527,8 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
 	if (req->i.waiting)
 		wake_up(&device->misc_wait);
 
-	if (c_put) {
-		if (drbd_req_put_completion_ref(req, m, c_put))
-			kref_put(&req->kref, drbd_req_destroy);
-	} else {
-		kref_put(&req->kref, drbd_req_destroy);
-	}
+	drbd_req_put_completion_ref(req, m, c_put);
+	kref_put(&req->kref, drbd_req_destroy);
 }
 
 static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req)
@@ -1366,8 +1370,7 @@ nodata:
 	}
 
 out:
-	if (drbd_req_put_completion_ref(req, &m, 1))
-		kref_put(&req->kref, drbd_req_destroy);
+	drbd_req_put_completion_ref(req, &m, 1);
 	spin_unlock_irq(&resource->req_lock);
 
 	/* Even though above is a kref_put(), this is safe.
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 28d932906f24..ebbd0c3fe0ed 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -608,6 +608,9 @@ static int loop_switch(struct loop_device *lo, struct file *file)
  */
 static int loop_flush(struct loop_device *lo)
 {
+	/* loop not yet configured, no running thread, nothing to flush */
+	if (lo->lo_state != Lo_bound)
+		return 0;
 	return loop_switch(lo, NULL);
 }
 
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 9a7bb2c29447..f3f191ba8ca4 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -937,14 +937,6 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
 	return -ENOSPC;
 }
 
-/* Reset all properties of an NBD device */
-static void nbd_reset(struct nbd_device *nbd)
-{
-	nbd->config = NULL;
-	nbd->tag_set.timeout = 0;
-	queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
-}
-
 static void nbd_bdev_reset(struct block_device *bdev)
 {
 	if (bdev->bd_openers > 1)
@@ -1029,7 +1021,11 @@ static void nbd_config_put(struct nbd_device *nbd)
 			}
 			kfree(config->socks);
 		}
-		nbd_reset(nbd);
+		kfree(nbd->config);
+		nbd->config = NULL;
+
+		nbd->tag_set.timeout = 0;
+		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
 
 		mutex_unlock(&nbd->config_lock);
 		nbd_put(nbd);
@@ -1483,7 +1479,6 @@ static int nbd_dev_add(int index)
 	disk->fops = &nbd_fops;
 	disk->private_data = nbd;
 	sprintf(disk->disk_name, "nbd%d", index);
-	nbd_reset(nbd);
 	add_disk(disk);
 	nbd_total_devices++;
 	return index;
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 454bf9c34882..c16f74547804 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4023,6 +4023,7 @@ static void rbd_queue_workfn(struct work_struct *work)
 
 	switch (req_op(rq)) {
 	case REQ_OP_DISCARD:
+	case REQ_OP_WRITE_ZEROES:
 		op_type = OBJ_OP_DISCARD;
 		break;
 	case REQ_OP_WRITE:
@@ -4420,6 +4421,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	q->limits.discard_granularity = segment_size;
 	q->limits.discard_alignment = segment_size;
 	blk_queue_max_discard_sectors(q, segment_size / SECTOR_SIZE);
+	blk_queue_max_write_zeroes_sectors(q, segment_size / SECTOR_SIZE);
 
 	if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
 		q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 8fe61b5dc5a6..1f3dfaa54d87 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -504,11 +504,13 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
 
 	dev_set_drvdata(&dev->dev, NULL);
 
-	if (be->blkif)
+	if (be->blkif) {
 		xen_blkif_disconnect(be->blkif);
 
-	/* Put the reference we set in xen_blkif_alloc(). */
-	xen_blkif_put(be->blkif);
+		/* Put the reference we set in xen_blkif_alloc(). */
+		xen_blkif_put(be->blkif);
+	}
+
 	kfree(be->mode);
 	kfree(be);
 	return 0;