Reverse order of arrays when --stop --scan

so that stacked arrays are stopped properly.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>

ChangeLog

@@ -13,6 +13,8 @@ Changes Prior to 1.9.0 release
     -   Add some missing closes of open file descriptors.
     -   Reread /proc/partition for every array assembled when using
 	it to find devices, rather than only once.
+    -   Make "mdadm -Ss" stop stacked devices properly, by reversing the
+	order in which arrays are stopped.
 
 Changes Prior to 1.8.0 release
     -   Makefile cleanup from  Luca Berra <bluca@comedia.it>

mdadm.c

@@ -793,6 +793,16 @@ int main(int argc, char *argv[])
 					/* apply to all devices in /proc/mdstat */
 					struct mdstat_ent *ms = mdstat_read(0);
 					struct mdstat_ent *e;
+					if (devmode == 'S') {
+						/* reverse order so that arrays made of arrays are stopped properly */
+						struct mdstat_ent *sm = NULL;
+						while ((e=ms) != NULL) {
+							ms = e->next;
+							e->next = sm;
+							sm = e;
+						}
+						ms = sm;
+					}
 					for (e=ms ; e ; e=e->next) {
 						char *name = get_md_name(e->devnum);