[PATCH 4/7] drbd: fix resync throttling initialization

From: Philipp Reisner
Date: Mon Nov 10 2014 - 11:22:51 EST


From: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>

If for some reason DRBD resync was the only activity on a backend
device, drbd_rs_c_min_rate_throttle() would mistakenly decide that it is
still initialization time, and keep throttling the resync.

This patch explicitly initializes ->rs_last_events to the current
backend event counters, and drops the rs_last_events == 0 from the
throttle condition.

Reported-by: Mikhail Sugakov <msugakov@xxxxxxxxx>

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

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 6960fb0..d169b4a 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2482,7 +2482,7 @@ bool drbd_rs_c_min_rate_throttle(struct drbd_device *device)
atomic_read(&device->rs_sect_ev);

if (atomic_read(&device->ap_actlog_cnt)
- || !device->rs_last_events || curr_events - device->rs_last_events > 64) {
+ || curr_events - device->rs_last_events > 64) {
unsigned long rs_left;
int i;

diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index 4529d92..2d7dd26 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -1099,7 +1099,6 @@ __drbd_set_state(struct drbd_device *device, union drbd_state ns,

set_ov_position(device, ns.conn);
device->rs_start = now;
- device->rs_last_events = 0;
device->rs_last_sect_ev = 0;
device->ov_last_oos_size = 0;
device->ov_last_oos_start = 0;
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index d2d1f97..d0fae55 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1592,11 +1592,15 @@ void drbd_resync_after_changed(struct drbd_device *device)

void drbd_rs_controller_reset(struct drbd_device *device)
{
+ struct gendisk *disk = device->ldev->backing_bdev->bd_contains->bd_disk;
struct fifo_buffer *plan;

atomic_set(&device->rs_sect_in, 0);
atomic_set(&device->rs_sect_ev, 0);
device->rs_in_flight = 0;
+ device->rs_last_events =
+ (int)part_stat_read(&disk->part0, sectors[0]) +
+ (int)part_stat_read(&disk->part0, sectors[1]);

/* Updating the RCU protected object in place is necessary since
this function gets called from atomic context.
@@ -1743,7 +1747,6 @@ void drbd_start_resync(struct drbd_device *device, enum drbd_conns side)
device->rs_failed = 0;
device->rs_paused = 0;
device->rs_same_csum = 0;
- device->rs_last_events = 0;
device->rs_last_sect_ev = 0;
device->rs_total = tw;
device->rs_start = now;
--
1.9.1

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