libceph, rbd: ceph_osd_linger_request, watch/notify v2

This adds support and switches rbd to a new, more reliable version of
watch/notify protocol.  As with the OSD client update, this is mostly
about getting the right structures linked into the right places so that
reconnects are properly sent when needed.  watch/notify v2 also
requires sending regular pings to the OSDs - send_linger_ping().

A major change from the old watch/notify implementation is the
introduction of ceph_osd_linger_request - linger requests no longer
piggy back on ceph_osd_request.  ceph_osd_event has been merged into
ceph_osd_linger_request.

All the details are now hidden within libceph, the interface consists
of a simple pair of watch/unwatch functions and ceph_osdc_notify_ack().
ceph_osdc_watch() does return ceph_osd_linger_request, but only to keep
the lifetime management simple.

ceph_osdc_notify_ack() accepts an optional data payload, which is
relayed back to the notifier.

Portions of this patch are loosely based on work by Douglas Fuller
<dfuller@redhat.com> and Mike Christie <michaelc@cs.wisc.edu>.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/net/ceph/debugfs.c b/net/ceph/debugfs.c
index 61dbd9d..e64cb85 100644
--- a/net/ceph/debugfs.c
+++ b/net/ceph/debugfs.c
@@ -177,6 +177,9 @@ static void dump_request(struct seq_file *s, struct ceph_osd_request *req)
 
 		seq_printf(s, "%s%s", (i == 0 ? "\t" : ","),
 			   ceph_osd_op_name(op->op));
+		if (op->op == CEPH_OSD_OP_WATCH)
+			seq_printf(s, "-%s",
+				   ceph_osd_watch_op_name(op->watch.op));
 	}
 
 	seq_putc(s, '\n');
@@ -197,6 +200,31 @@ static void dump_requests(struct seq_file *s, struct ceph_osd *osd)
 	mutex_unlock(&osd->lock);
 }
 
+static void dump_linger_request(struct seq_file *s,
+				struct ceph_osd_linger_request *lreq)
+{
+	seq_printf(s, "%llu\t", lreq->linger_id);
+	dump_target(s, &lreq->t);
+
+	seq_printf(s, "\t%u\t%s/%d\n", lreq->register_gen,
+		   lreq->committed ? "C" : "", lreq->last_error);
+}
+
+static void dump_linger_requests(struct seq_file *s, struct ceph_osd *osd)
+{
+	struct rb_node *n;
+
+	mutex_lock(&osd->lock);
+	for (n = rb_first(&osd->o_linger_requests); n; n = rb_next(n)) {
+		struct ceph_osd_linger_request *lreq =
+		    rb_entry(n, struct ceph_osd_linger_request, node);
+
+		dump_linger_request(s, lreq);
+	}
+
+	mutex_unlock(&osd->lock);
+}
+
 static int osdc_show(struct seq_file *s, void *pp)
 {
 	struct ceph_client *client = s->private;
@@ -214,6 +242,14 @@ static int osdc_show(struct seq_file *s, void *pp)
 	}
 	dump_requests(s, &osdc->homeless_osd);
 
+	seq_puts(s, "LINGER REQUESTS\n");
+	for (n = rb_first(&osdc->osds); n; n = rb_next(n)) {
+		struct ceph_osd *osd = rb_entry(n, struct ceph_osd, o_node);
+
+		dump_linger_requests(s, osd);
+	}
+	dump_linger_requests(s, &osdc->homeless_osd);
+
 	up_read(&osdc->lock);
 	return 0;
 }