libceph: add ceph_monc_wait_osdmap()

Add ceph_monc_wait_osdmap(), which will block until the osdmap with the
specified epoch is received or timeout occurs.

Export both of these as they are going to be needed by rbd.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

2 files changed, 29 insertions, 0 deletions

diff --git a/include/linux/ceph/mon_client.h b/include/linux/ceph/mon_client.h
index 585ef9450e9d..deb47e45ac7c 100644
--- a/include/linux/ceph/mon_client.h
+++ b/include/linux/ceph/mon_client.h
@@ -104,6 +104,8 @@ extern int ceph_monc_got_mdsmap(struct ceph_mon_client *monc, u32 have);
 extern int ceph_monc_got_osdmap(struct ceph_mon_client *monc, u32 have);
 
 extern void ceph_monc_request_next_osdmap(struct ceph_mon_client *monc);
+extern int ceph_monc_wait_osdmap(struct ceph_mon_client *monc, u32 epoch,
+                                 unsigned long timeout);
 
 extern int ceph_monc_do_statfs(struct ceph_mon_client *monc,
                                struct ceph_statfs *buf);
diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
index 11d8d2f2708a..067d3af2eaf6 100644
--- a/net/ceph/mon_client.c
+++ b/net/ceph/mon_client.c
@@ -296,6 +296,33 @@ void ceph_monc_request_next_osdmap(struct ceph_mon_client *monc)
                 __send_subscribe(monc);
         mutex_unlock(&monc->mutex);
 }
+EXPORT_SYMBOL(ceph_monc_request_next_osdmap);
+
+int ceph_monc_wait_osdmap(struct ceph_mon_client *monc, u32 epoch,
+                          unsigned long timeout)
+{
+        unsigned long started = jiffies;
+        int ret;
+
+        mutex_lock(&monc->mutex);
+        while (monc->have_osdmap < epoch) {
+                mutex_unlock(&monc->mutex);
+
+                if (timeout != 0 && time_after_eq(jiffies, started + timeout))
+                        return -ETIMEDOUT;
+
+                ret = wait_event_interruptible_timeout(monc->client->auth_wq,
+                                         monc->have_osdmap >= epoch, timeout);
+                if (ret < 0)
+                        return ret;
+
+                mutex_lock(&monc->mutex);
+        }
+
+        mutex_unlock(&monc->mutex);
+        return 0;
+}
+EXPORT_SYMBOL(ceph_monc_wait_osdmap);
 
 /*
  *