engines/rbd: add support for rbd_invalidate_cache()

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/configure b/configure
index 988fb63..da637a9 100755
--- a/configure
+++ b/configure
@@ -1203,6 +1203,43 @@
 echo "Rados Block Device engine     $rbd"
 
 ##########################################
+# check for rbd_invaidate_cache()
+rbd_inval="no"
+if test "$rbd" = "yes"; then
+cat > $TMPC << EOF
+#include <rbd/librbd.h>
+
+int main(int argc, char **argv)
+{
+  rbd_image_t image;
+
+  return rbd_invalidate_cache(image);
+}
+EOF
+if compile_prog "" "-lrbd -lrados" "rbd"; then
+  rbd_inval="yes"
+fi
+echo "rbd_invalidate_cache          $rbd_inval"
+fi
+
+##########################################
+# Check whether we have setvbuf
+setvbuf="no"
+cat > $TMPC << EOF
+#include <stdio.h>
+int main(int argc, char **argv)
+{
+  FILE *f = NULL;
+  char buf[80];
+  setvbuf(f, buf, _IOFBF, sizeof(buf));
+  return 0;
+}
+EOF
+if compile_prog "" "" "setvbuf"; then
+  setvbuf="yes"
+fi
+echo "setvbuf                       $setvbuf"
+
 # check for gfapi
 gfapi="no"
 cat > $TMPC << EOF
@@ -1472,6 +1509,9 @@
 if test "$rbd" = "yes" ; then
   output_sym "CONFIG_RBD"
 fi
+if test "$rbd_inval" = "yes" ; then
+  output_sym "CONFIG_RBD_INVAL"
+fi
 if test "$setvbuf" = "yes" ; then
   output_sym "CONFIG_SETVBUF"
 fi