drbd: Implemented real timeout checking for request processing time

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

5 files changed, 47 insertions, 0 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 267d9897ca8c..81030d8d654b 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -990,6 +990,7 @@ struct drbd_conf {
         struct timer_list resync_timer;
         struct timer_list md_sync_timer;
         struct timer_list start_resync_timer;
+        struct timer_list request_timer;
 #ifdef DRBD_DEBUG_MD_SYNC
         struct {
                 unsigned int line;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 9043772de400..dfc85f32d317 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3017,12 +3017,15 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
         init_timer(&mdev->resync_timer);
         init_timer(&mdev->md_sync_timer);
         init_timer(&mdev->start_resync_timer);
+        init_timer(&mdev->request_timer);
         mdev->resync_timer.function = resync_timer_fn;
         mdev->resync_timer.data = (unsigned long) mdev;
         mdev->md_sync_timer.function = md_sync_timer_fn;
         mdev->md_sync_timer.data = (unsigned long) mdev;
         mdev->start_resync_timer.function = start_resync_timer_fn;
         mdev->start_resync_timer.data = (unsigned long) mdev;
+        mdev->request_timer.function = request_timer_fn;
+        mdev->request_timer.data = (unsigned long) mdev;
 
         init_waitqueue_head(&mdev->misc_wait);
         init_waitqueue_head(&mdev->state_wait);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 3d62ac7cdc4a..fe1564c7d8b6 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -912,6 +912,7 @@ retry:
         drbd_send_state(mdev);
         clear_bit(USE_DEGR_WFC_T, &mdev->flags);
         clear_bit(RESIZE_PENDING, &mdev->flags);
+        mod_timer(&mdev->request_timer, jiffies + HZ); /* just start it here. */
 
         return 1;
 
@@ -3822,6 +3823,8 @@ static void drbd_disconnect(struct drbd_conf *mdev)
         atomic_set(&mdev->rs_pending_cnt, 0);
         wake_up(&mdev->misc_wait);
 
+        del_timer(&mdev->request_timer);
+
         /* make sure syncer is stopped and w_resume_next_sg queued */
         del_timer_sync(&mdev->resync_timer);
         resync_timer_fn((unsigned long)mdev);
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 94fd5a2be559..c2cc28a55907 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1194,3 +1194,42 @@ int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct
         }
         return limit;
 }
+
+void request_timer_fn(unsigned long data)
+{
+        struct drbd_conf *mdev = (struct drbd_conf *) data;
+        struct drbd_request *req; /* oldest request */
+        struct list_head *le;
+        unsigned long et = 0; /* effective timeout = ko_count * timeout */
+
+        if (get_net_conf(mdev)) {
+                et = mdev->net_conf->timeout*HZ/10 * mdev->net_conf->ko_count;
+                put_net_conf(mdev);
+        }
+        if (!et || mdev->state.conn < C_WF_REPORT_PARAMS)
+                return; /* Recurring timer stopped */
+
+        spin_lock_irq(&mdev->req_lock);
+        le = &mdev->oldest_tle->requests;
+        if (list_empty(le)) {
+                spin_unlock_irq(&mdev->req_lock);
+                mod_timer(&mdev->request_timer, jiffies + et);
+                return;
+        }
+
+        le = le->prev;
+        req = list_entry(le, struct drbd_request, tl_requests);
+        if (time_is_before_eq_jiffies(req->start_time + et)) {
+                if (req->rq_state & RQ_NET_PENDING) {
+                        dev_warn(DEV, "Remote failed to finish a request within ko-count * timeout\n");
+                        _drbd_set_state(_NS(mdev, conn, C_TIMEOUT), CS_VERBOSE, NULL);
+                } else {
+                        dev_warn(DEV, "Local backing block device frozen?\n");
+                        mod_timer(&mdev->request_timer, jiffies + et);
+                }
+        } else {
+                mod_timer(&mdev->request_timer, req->start_time + et);
+        }
+
+        spin_unlock_irq(&mdev->req_lock);
+}
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 32c1f2a31266..32e2c3e6a813 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -322,6 +322,7 @@ extern int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 struct bio_and_error *m);
 extern void complete_master_bio(struct drbd_conf *mdev,
                 struct bio_and_error *m);
+extern void request_timer_fn(unsigned long data);
 
 /* use this if you don't want to deal with calling complete_master_bio()
  * outside the spinlock, e.g. when walking some list on cleanup. */