drbd: Track the numbers of sectors in flight

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

4 files changed, 21 insertions, 6 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index bcba2742cfba..c804e44b9455 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1102,6 +1102,7 @@ struct drbd_conf {
         struct fifo_buffer rs_plan_s; /* correction values of resync planer */
         int rs_in_flight; /* resync sectors in flight (to proxy, in proxy and from proxy) */
         int rs_planed;    /* resync sectors already planed */
+        atomic_t ap_in_flight; /* App sectors in flight (waiting for ack) */
 };
 
 static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 9d9c2ed31e9a..e81d009dd061 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2799,6 +2799,7 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
         atomic_set(&mdev->pp_in_use_by_net, 0);
         atomic_set(&mdev->rs_sect_in, 0);
         atomic_set(&mdev->rs_sect_ev, 0);
+        atomic_set(&mdev->ap_in_flight, 0);
 
         mutex_init(&mdev->md_io_mutex);
         mutex_init(&mdev->data.mutex);
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 08f53ce9b88f..5c60d77d447c 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -558,6 +558,9 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
 
         case handed_over_to_network:
                 /* assert something? */
+                if (bio_data_dir(req->master_bio) == WRITE)
+                        atomic_add(req->size>>9, &mdev->ap_in_flight);
+
                 if (bio_data_dir(req->master_bio) == WRITE &&
                     mdev->net_conf->wire_protocol == DRBD_PROT_A) {
                         /* this is what is dangerous about protocol A:
@@ -591,6 +594,9 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                         dec_ap_pending(mdev);
                 req->rq_state &= ~(RQ_NET_OK|RQ_NET_PENDING);
                 req->rq_state |= RQ_NET_DONE;
+                if (req->rq_state & RQ_NET_SENT && req->rq_state & RQ_WRITE)
+                        atomic_sub(req->size>>9, &mdev->ap_in_flight);
+
                 /* if it is still queued, we may not complete it here.
                  * it will be canceled soon. */
                 if (!(req->rq_state & RQ_NET_QUEUED))
@@ -628,14 +634,17 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 req->rq_state |= RQ_NET_OK;
                 D_ASSERT(req->rq_state & RQ_NET_PENDING);
                 dec_ap_pending(mdev);
+                atomic_sub(req->size>>9, &mdev->ap_in_flight);
                 req->rq_state &= ~RQ_NET_PENDING;
                 _req_may_be_done_not_susp(req, m);
                 break;
 
         case neg_acked:
                 /* assert something? */
-                if (req->rq_state & RQ_NET_PENDING)
+                if (req->rq_state & RQ_NET_PENDING) {
                         dec_ap_pending(mdev);
+                        atomic_sub(req->size>>9, &mdev->ap_in_flight);
+                }
                 req->rq_state &= ~(RQ_NET_OK|RQ_NET_PENDING);
 
                 req->rq_state |= RQ_NET_DONE;
@@ -692,6 +701,8 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 }
                 D_ASSERT(req->rq_state & RQ_NET_SENT);
                 req->rq_state |= RQ_NET_DONE;
+                if (mdev->net_conf->wire_protocol == DRBD_PROT_A)
+                        atomic_sub(req->size>>9, &mdev->ap_in_flight);
                 _req_may_be_done(req, m); /* Allowed while state.susp */
                 break;
 
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index ab2bd09d54b4..69d350fe7c1e 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -338,19 +338,21 @@ static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what)
         return rv;
 }
 
-/* completion of master bio is outside of spinlock.
- * If you need it irqsave, do it your self!
- * Which means: don't use from bio endio callback. */
+/* completion of master bio is outside of our spinlock.
+ * We still may or may not be inside some irqs disabled section
+ * of the lower level driver completion callback, so we need to
+ * spin_lock_irqsave here. */
 static inline int req_mod(struct drbd_request *req,
                 enum drbd_req_event what)
 {
+        unsigned long flags;
         struct drbd_conf *mdev = req->mdev;
         struct bio_and_error m;
         int rv;
 
-        spin_lock_irq(&mdev->req_lock);
+        spin_lock_irqsave(&mdev->req_lock, flags);
         rv = __req_mod(req, what, &m);
-        spin_unlock_irq(&mdev->req_lock);
+        spin_unlock_irqrestore(&mdev->req_lock, flags);
 
         if (m.bio)
                 complete_master_bio(mdev, &m);