Maria: it is allowed to change unknown type to any legal type of page

in the pagecache: fixing wrong assertion and a test case.
maria.test and ps_maria.test still fail.


mysql-test/r/maria.result:
  result update
mysql-test/t/maria.test:
  added test for incorrect assert on page's type
storage/maria/ma_pagecache.c:
  It is allowed to change unknown type to any legal type of page in the
  pagecache.

mysql-test/r/maria.result

@@ -33,6 +33,10 @@ test.t1	repair	status	OK
 check table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
+flush table t1;
+repair table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	repair	status	OK
 drop table t1;
 create table t1 (a int not null auto_increment, b int not null, primary key (a), index(b));
 insert into t1 (b) values (1),(2),(2),(2),(2);

mysql-test/t/maria.test

@@ -57,6 +57,10 @@ delete from t1 where (a & 1);
 check table t1;
 repair table t1;
 check table t1;
+
+# FLUSH + REPAIR used to cause assertion failure in page cache
+flush table t1;
+repair table t1;
 drop table t1;
 
 #

storage/maria/ma_pagecache.c

@@ -2865,7 +2865,9 @@ uchar *pagecache_valid_read(PAGECACHE *pagecache,
                            (pin == PAGECACHE_PIN)),
                       &page_st);
     DBUG_ASSERT(block->type == PAGECACHE_EMPTY_PAGE ||
-                block->type == type || type == PAGECACHE_READ_UNKNOWN_PAGE);
+                block->type == type ||
+                type == PAGECACHE_READ_UNKNOWN_PAGE ||
+                block->type == PAGECACHE_READ_UNKNOWN_PAGE);
     if (type != PAGECACHE_READ_UNKNOWN_PAGE ||
         block->type == PAGECACHE_EMPTY_PAGE)
       block->type= type;