1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 9a944604939f..38bbaba8bd89 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -2213,8 +2213,9 @@ static inline int drbd_get_max_buffers(struct drbd_conf *mdev)
         return mxb;
 }
 
-static inline int drbd_state_is_stable(union drbd_state s)
+static inline int drbd_state_is_stable(struct drbd_conf *mdev)
 {
+        union drbd_state s = mdev->state;
 
         /* DO NOT add a default clause, we want the compiler to warn us
          * for any newly introduced state we may have forgotten to add here */
@@ -2233,11 +2234,7 @@ static inline int drbd_state_is_stable(union drbd_state s)
         case C_PAUSED_SYNC_T:
         case C_AHEAD:
         case C_BEHIND:
-                /* maybe stable, look at the disk state */
-                break;
-
-        /* no new io accepted during tansitional states
-         * like handshake or teardown */
+                /* transitional states, IO allowed */
         case C_DISCONNECTING:
         case C_UNCONNECTED:
         case C_TIMEOUT:
@@ -2248,7 +2245,15 @@ static inline int drbd_state_is_stable(union drbd_state s)
         case C_WF_REPORT_PARAMS:
         case C_STARTING_SYNC_S:
         case C_STARTING_SYNC_T:
+                break;
+
+                /* Allow IO in BM exchange states with new protocols */
         case C_WF_BITMAP_S:
+                if (mdev->agreed_pro_version < 96)
+                        return 0;
+                break;
+
+                /* no new io accepted in these states */
         case C_WF_BITMAP_T:
         case C_WF_SYNC_UUID:
         case C_MASK:
@@ -2297,7 +2302,7 @@ static inline int __inc_ap_bio_cond(struct drbd_conf *mdev)
          * to start during "stable" states. */
 
         /* no new io accepted when attaching or detaching the disk */
-        if (!drbd_state_is_stable(mdev->state))
+        if (!drbd_state_is_stable(mdev))
                 return 0;
 
         /* since some older kernels don't have atomic_add_unless,