[Patch v2 03/10] drbd: A function to zero out drbd backing device

[Nick Wang <nwang@suse.com>]

The function can be used to zero out the whole
backing device.

Signed-off-by: Nick Wang <nwang@suse.com>
CC: Philipp Reisner <philipp.reisner@linbit.com>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
CC: drbd-dev@lists.linbit.com
CC: linux-kernel@vger.kernel.org
---
 drbd/drbd_int.h    |  1 +
 drbd/drbd_worker.c | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drbd/drbd_int.h b/drbd/drbd_int.h
index a234228..9ecf971 100644
--- a/drbd/drbd_int.h
+++ b/drbd/drbd_int.h
@@ -1662,6 +1662,7 @@ extern void drbd_send_acks_wf(struct work_struct *ws);
 extern bool drbd_rs_c_min_rate_throttle(struct drbd_device *device);
 extern bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector,
 		bool throttle_if_app_is_waiting);
+extern int zero_out_local_device(struct drbd_device *device);
 extern int drbd_submit_peer_request(struct drbd_device *,
 				    struct drbd_peer_request *, const unsigned,
 				    const int);
diff --git a/drbd/drbd_worker.c b/drbd/drbd_worker.c
index 2a15aeb..50564f5 100644
--- a/drbd/drbd_worker.c
+++ b/drbd/drbd_worker.c
@@ -1653,6 +1653,27 @@ void drbd_rs_controller_reset(struct drbd_device *device)
 	rcu_read_unlock();
 }
 
+/**
+ * zero_out_local_device()
+ * @device: DRBD device.
+ *
+ * Description:
+ * Zero out drbd backing device when creating new uuid.
+ *
+**/
+int zero_out_local_device(struct drbd_device *device)
+{
+	struct block_device *bdev;
+
+	bdev = device->ldev->backing_bdev;
+	if (device->ldev->known_size != drbd_get_capacity(bdev))
+		device->ldev->known_size = drbd_get_capacity(bdev);
+
+	/* zero out the backing device */
+	return blkdev_issue_zeroout(bdev, 0,
+		device->ldev->known_size, GFP_NOIO, false);
+}
+
 void start_resync_timer_fn(unsigned long data)
 {
 	struct drbd_device *device = (struct drbd_device *) data;
-- 
1.8.4.5