qa: krbd latest-osdmap-on-map test

Make sure we get the latest osdmap when using an existing client.

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

qa/suites/krbd/rbd-nomount/tasks/krbd_latest_osdmap_on_map.yaml

@@ -0,0 +1,5 @@
+tasks:
+- workunit:
+    clients:
+      all:
+        - rbd/krbd_latest_osdmap_on_map.sh

qa/workunits/rbd/krbd_latest_osdmap_on_map.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+set -ex
+
+function run_test() {
+    ceph osd pool create foo 12
+    rbd pool init foo
+    rbd create --size 1 foo/img
+
+    local dev
+    dev=$(sudo rbd map foo/img)
+    sudo rbd unmap $dev
+
+    ceph osd pool delete foo foo --yes-i-really-really-mean-it
+}
+
+NUM_ITER=20
+
+for ((i = 0; i < $NUM_ITER; i++)); do
+    run_test
+done
+
+rbd create --size 1 img
+DEV=$(sudo rbd map img)
+for ((i = 0; i < $NUM_ITER; i++)); do
+    run_test
+done
+sudo rbd unmap $DEV
+
+echo OK