drbd: fix "stalled" empty resync

With sync-after dependencies, given "lucky" timing of pause/unpause
events, and the end of an empty (0 bits set) resync was sometimes not
detected on the SyncTarget, leading to a "stalled" SyncSource state.

Fixed this by expecting not only "Inconsistent -> UpToDate" but also
"Consistent -> UpToDate" transitions for the peer disk state
to end a resync.

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

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index e64b1c8..16c3710 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -2262,7 +2262,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 
        if (rs.no_resync && mdev->tconn->agreed_pro_version < 93) {
                retcode = ERR_NEED_APV_93;
-               goto fail;
+               goto fail_ldev;
        }
 
        rcu_read_lock();
@@ -2272,7 +2272,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
                new_disk_conf = kmalloc(sizeof(struct disk_conf), GFP_KERNEL);
                if (!new_disk_conf) {
                        retcode = ERR_NOMEM;
-                       goto fail;
+                       goto fail_ldev;
                }
        }
 
@@ -2310,6 +2310,10 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
  fail:
        drbd_adm_finish(info, retcode);
        return 0;
+
+ fail_ldev:
+       put_ldev(mdev);
+       goto fail;
 }
 
 int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info)

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 4004a68..aba04d7 100644 (file)
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3748,9 +3748,14 @@ static int receive_state(struct drbd_tconn *tconn, struct packet_info *pi)
        os = ns = drbd_read_state(mdev);
        spin_unlock_irq(&mdev->tconn->req_lock);
 
-       /* peer says his disk is uptodate, while we think it is inconsistent,
-        * and this happens while we think we have a sync going on. */
-       if (os.pdsk == D_INCONSISTENT && real_peer_disk == D_UP_TO_DATE &&
+       /* If this is the "end of sync" confirmation, usually the peer disk
+        * transitions from D_INCONSISTENT to D_UP_TO_DATE. For empty (0 bits
+        * set) resync started in PausedSyncT, or if the timing of pause-/
+        * unpause-sync events has been "just right", the peer disk may
+        * transition from D_CONSISTENT to D_UP_TO_DATE as well.
+        */
+       if ((os.pdsk == D_INCONSISTENT || os.pdsk == D_CONSISTENT) &&
+           real_peer_disk == D_UP_TO_DATE &&
            os.conn > C_CONNECTED && os.disk == D_UP_TO_DATE) {
                /* If we are (becoming) SyncSource, but peer is still in sync
                 * preparation, ignore its uptodate-ness to avoid flapping, it