[PATCH 06/30] drbd: Create the protocol feature THIN_RESYNC

From: Philipp Reisner
Date: Mon Jun 13 2016 - 10:23:13 EST


If thinly provisioned volumes are used, during a resync the sync source
tries to find out if a block is deallocated. If it is deallocated, then
the resync target uses block_dev_issue_zeroout() on the range in
question.

Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
---
drivers/block/drbd/drbd_protocol.h | 1 +
drivers/block/drbd/drbd_receiver.c | 5 ++++-
drivers/block/drbd/drbd_worker.c | 13 ++++++++++++-
3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
index e5e74e3..7acc2e0 100644
--- a/drivers/block/drbd/drbd_protocol.h
+++ b/drivers/block/drbd/drbd_protocol.h
@@ -165,6 +165,7 @@ struct p_block_req {
*/

#define FF_TRIM 1
+#define FF_THIN_RESYNC 2

struct p_connection_features {
u32 protocol_min;
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 3a6c2ec..4cfc721 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -48,7 +48,7 @@
#include "drbd_req.h"
#include "drbd_vli.h"

-#define PRO_FEATURES (FF_TRIM)
+#define PRO_FEATURES (FF_TRIM | FF_THIN_RESYNC)

struct packet_info {
enum drbd_packet cmd;
@@ -4979,6 +4979,9 @@ static int drbd_do_features(struct drbd_connection *connection)
drbd_info(connection, "Agreed to%ssupport TRIM on protocol level\n",
connection->agreed_features & FF_TRIM ? " " : " not ");

+ drbd_info(connection, "Agreed to%ssupport THIN_RESYNC on protocol level\n",
+ connection->agreed_features & FF_THIN_RESYNC ? " " : " not ");
+
return 1;

incompat:
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 01d74ee2..fa63c22 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -582,6 +582,7 @@ static int make_resync_request(struct drbd_device *const device, int cancel)
int number, rollback_i, size;
int align, requeue = 0;
int i = 0;
+ int discard_granularity = 0;

if (unlikely(cancel))
return 0;
@@ -601,6 +602,12 @@ static int make_resync_request(struct drbd_device *const device, int cancel)
return 0;
}

+ if (connection->agreed_features & FF_THIN_RESYNC) {
+ rcu_read_lock();
+ discard_granularity = rcu_dereference(device->ldev->disk_conf)->rs_discard_granularity;
+ rcu_read_unlock();
+ }
+
max_bio_size = queue_max_hw_sectors(device->rq_queue) << 9;
number = drbd_rs_number_requests(device);
if (number <= 0)
@@ -665,6 +672,9 @@ next_sector:
if (sector & ((1<<(align+3))-1))
break;

+ if (discard_granularity && size == discard_granularity)
+ break;
+
/* do not cross extent boundaries */
if (((bit+1) & BM_BLOCKS_PER_BM_EXT_MASK) == 0)
break;
@@ -711,7 +721,8 @@ next_sector:
int err;

inc_rs_pending(device);
- err = drbd_send_drequest(peer_device, P_RS_DATA_REQUEST,
+ err = drbd_send_drequest(peer_device,
+ size == discard_granularity ? P_RS_THIN_REQ : P_RS_DATA_REQUEST,
sector, size, ID_SYNCER);
if (err) {
drbd_err(device, "drbd_send_drequest() failed, aborting...\n");
--
2.7.4