staging: lustre: llog: add newly opened llog at tail of handle list

Add newly opened llog handle at the tail of handle list to increase
lookup speed, especially for cancel operation, because the canceled
log will be removed from the list, and lookup is from the beginning.
Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Li Xi <lixi@ddn.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5405
Reviewed-on: http://review.whamcloud.com/11575Reviewed-by: Ian Costello <costello.ian@gmail.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/llog_cat.c

@@ -107,7 +107,7 @@ static int llog_cat_id2handle(const struct lu_env *env,
 	}
 
 	down_write(&cathandle->lgh_lock);
-	list_add(&loghandle->u.phd.phd_entry, &cathandle->u.chd.chd_head);
+	list_add_tail(&loghandle->u.phd.phd_entry, &cathandle->u.chd.chd_head);
 	up_write(&cathandle->lgh_lock);
 
 	loghandle->u.phd.phd_cat_handle = cathandle;