drbd: send intermediate state change results to the peer
DRBD state changes schedule after_state_ch() actions to a worker thread,
which decides on the old and new states of that change, whether to send
an informational state update packet (P_STATE) to the peer.
If it decides to drbd_send_state(), it would however always send the
_curent_ state, which, if a second state change happens before the
after_state_ch() of the first ran, may "fast-forward" the peer's view
about this node. In most cases that is harmless, but sometimes this can
confuse DRBD, for example into not actually starting a necessary resync
if you do a very tight detach/attach loop on a Connected Secondary.
Fix this by always sending the "new" state of the respective state
transition which scheduled this after_state_ch() work.
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_int.h b/drivers/block/drbd/drbd_int.h
index c7976a7..31dee20 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1229,8 +1229,8 @@
extern int drbd_send_uuids_skip_initial_sync(struct drbd_conf *mdev);
extern int drbd_gen_and_send_sync_uuid(struct drbd_conf *mdev);
extern int drbd_send_sizes(struct drbd_conf *mdev, int trigger_reply, enum dds_flags flags);
-extern int _drbd_send_state(struct drbd_conf *mdev);
-extern int drbd_send_state(struct drbd_conf *mdev);
+extern int drbd_send_state(struct drbd_conf *mdev, union drbd_state s);
+extern int drbd_send_current_state(struct drbd_conf *mdev);
extern int _drbd_send_cmd(struct drbd_conf *mdev, struct socket *sock,
enum drbd_packets cmd, struct p_header80 *h,
size_t size, unsigned msg_flags);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 64318d4..3a5b4de 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1487,7 +1487,7 @@
/* Do not change the order of the if above and the two below... */
if (os.pdsk == D_DISKLESS && ns.pdsk > D_DISKLESS) { /* attach on the peer */
drbd_send_uuids(mdev);
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
}
/* No point in queuing send_bitmap if we don't have a connection
* anymore, so check also the _current_ state, not only the new state
@@ -1552,14 +1552,14 @@
os.disk == D_ATTACHING && ns.disk == D_NEGOTIATING) {
drbd_send_sizes(mdev, 0, 0); /* to start sync... */
drbd_send_uuids(mdev);
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
}
/* We want to pause/continue resync, tell peer. */
if (ns.conn >= C_CONNECTED &&
((os.aftr_isp != ns.aftr_isp) ||
(os.user_isp != ns.user_isp)))
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
/* In case one of the isp bits got set, suspend other devices. */
if ((!os.aftr_isp && !os.peer_isp && !os.user_isp) &&
@@ -1569,10 +1569,10 @@
/* Make sure the peer gets informed about eventual state
changes (ISP bits) while we were in WFReportParams. */
if (os.conn == C_WF_REPORT_PARAMS && ns.conn >= C_CONNECTED)
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
if (os.conn != C_AHEAD && ns.conn == C_AHEAD)
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
/* We are in the progress to start a full sync... */
if ((os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
@@ -1612,7 +1612,7 @@
"ASSERT FAILED: disk is %s during detach\n",
drbd_disk_str(mdev->state.disk));
- if (drbd_send_state(mdev))
+ if (drbd_send_state(mdev, ns))
dev_info(DEV, "Notified peer that I am detaching my disk\n");
drbd_rs_cancel_all(mdev);
@@ -1642,7 +1642,7 @@
mdev->rs_failed = 0;
atomic_set(&mdev->rs_pending_cnt, 0);
- if (drbd_send_state(mdev))
+ if (drbd_send_state(mdev, ns))
dev_info(DEV, "Notified peer that I'm now diskless.\n");
/* corresponding get_ldev in __drbd_set_state
* this may finally trigger drbd_ldev_destroy. */
@@ -1651,7 +1651,7 @@
/* Notify peer that I had a local IO error, and did not detached.. */
if (os.disk == D_UP_TO_DATE && ns.disk == D_INCONSISTENT)
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
/* Disks got bigger while they were detached */
if (ns.disk > D_NEGOTIATING && ns.pdsk > D_NEGOTIATING &&
@@ -1669,7 +1669,7 @@
/* sync target done with resync. Explicitly notify peer, even though
* it should (at least for non-empty resyncs) already know itself. */
if (os.disk < D_UP_TO_DATE && os.conn >= C_SYNC_SOURCE && ns.conn == C_CONNECTED)
- drbd_send_state(mdev);
+ drbd_send_state(mdev, ns);
/* This triggers bitmap writeout of potentially still unwritten pages
* if the resync finished cleanly, or aborted because of peer disk
@@ -2191,10 +2191,10 @@
}
/**
- * drbd_send_state() - Sends the drbd state to the peer
+ * drbd_send_current_state() - Sends the drbd state to the peer
* @mdev: DRBD device.
*/
-int drbd_send_state(struct drbd_conf *mdev)
+int drbd_send_current_state(struct drbd_conf *mdev)
{
struct socket *sock;
struct p_state p;
@@ -2220,6 +2220,37 @@
return ok;
}
+/**
+ * drbd_send_state() - After a state change, sends the new state to the peer
+ * @mdev: DRBD device.
+ * @state: the state to send, not necessarily the current state.
+ *
+ * Each state change queues an "after_state_ch" work, which will eventually
+ * send the resulting new state to the peer. If more state changes happen
+ * between queuing and processing of the after_state_ch work, we still
+ * want to send each intermediary state in the order it occurred.
+ */
+int drbd_send_state(struct drbd_conf *mdev, union drbd_state state)
+{
+ struct socket *sock;
+ struct p_state p;
+ int ok = 0;
+
+ mutex_lock(&mdev->data.mutex);
+
+ p.state = cpu_to_be32(state.i);
+ sock = mdev->data.socket;
+
+ if (likely(sock != NULL)) {
+ ok = _drbd_send_cmd(mdev, sock, P_STATE,
+ (struct p_header80 *)&p, sizeof(p), 0);
+ }
+
+ mutex_unlock(&mdev->data.mutex);
+
+ return ok;
+}
+
int drbd_send_state_req(struct drbd_conf *mdev,
union drbd_state mask, union drbd_state val)
{
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 00a82ab..1bbbad3 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -432,7 +432,7 @@
/* if this was forced, we should consider sync */
if (forced)
drbd_send_uuids(mdev);
- drbd_send_state(mdev);
+ drbd_send_current_state(mdev);
}
drbd_md_sync(mdev);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 1a48e02..f0d86cb3 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -899,7 +899,7 @@
drbd_send_sync_param(mdev, &mdev->sync_conf);
drbd_send_sizes(mdev, 0, 0);
drbd_send_uuids(mdev);
- drbd_send_state(mdev);
+ drbd_send_current_state(mdev);
clear_bit(USE_DEGR_WFC_T, &mdev->flags);
clear_bit(RESIZE_PENDING, &mdev->flags);
@@ -3294,7 +3294,7 @@
/* Nowadays only used when forcing a node into primary role and
setting its disk to UpToDate with that */
drbd_send_uuids(mdev);
- drbd_send_state(mdev);
+ drbd_send_current_state(mdev);
}
}