MDEV-22970: Disable MDEV-8139 due to corruption concerns

Contrary to our exceptations, it seems that a mini-transaction can
allocate a page that it had freed earlier. The function mtr_t::init()
is not prepared to deal with this, and it could happen that a
newly initialized page will be scrubbed instead. This can affect
the operation on page_compressed tables, or any InnoDB data files when
innodb_background_scrub_data_uncompressed=ON.

Also, buf_read_recv_pages() can interfere with the MDEV-8139 logic
during crash recovery.

Let us temporarily disable MDEV-8139 due to such concerns.

Note: Scrubbing will partially work thanks to MDEV-15528. Only in
cases where the page does not exist in the buffer pool at the time
of the page flush, we would skip the scrubbing action.

mysql-test/suite/innodb/disabled.def

@@ -12,3 +12,4 @@
 
 create-index-debug : MDEV-13680 InnoDB may crash when btr_page_alloc() fails
 innodb_force_recovery_rollback : MDEV-22889 InnoDB occasionally breaks ACID
+innodb_scrub : MDEV-8139/MDEV-22970 Fix scrubbing

storage/innobase/buf/buf0buf.cc

@@ -2632,8 +2632,14 @@ void buf_page_free(const page_id_t page_id,
   buf_block_t *block= reinterpret_cast<buf_block_t*>
     (buf_pool.page_hash_get_low(page_id, fold));
 
+#if 0 /* FIXME: MDEV-22970 Potential corruption */
+  /* TODO: Find out how and when a freed page can be marked
+  allocated in the same mini-transaction. At least it seems to
+  happen during a pessimistic insert operation. */
+  /* TODO: try to all this part of mtr_t::free() */
   if (srv_immediate_scrub_data_uncompressed || mtr->is_page_compressed())
     mtr->add_freed_offset(page_id);
+#endif
 
   if (!block || block->page.state() != BUF_BLOCK_FILE_PAGE)
   {

storage/innobase/log/log0recv.cc

@@ -1777,6 +1777,7 @@ inline void recv_sys_t::add(const page_id_t page_id,
                   log_phys_t(start_lsn, lsn, l, len));
 }
 
+#if 0 /* FIXME: MDEV-22970 Potential corruption */
 /** Store/remove the freed pages in fil_name_t of recv_spaces.
 @param[in]	page_id		freed or init page_id
 @param[in]	freed		TRUE if page is freed */
@@ -1805,6 +1806,7 @@ static void store_freed_or_init_rec(page_id_t page_id, bool freed)
       i->second.remove_freed_page(page_no);
   }
 }
+#endif
 
 /** Parse and register one mini-transaction in log_t::FORMAT_10_5.
 @param checkpoint_lsn  the log sequence number of the latest checkpoint
@@ -2004,7 +2006,9 @@ bool recv_sys_t::parse(lsn_t checkpoint_lsn, store_t *store, bool apply)
       case INIT_PAGE:
         last_offset= FIL_PAGE_TYPE;
       free_or_init_page:
+#if 0 /* FIXME: MDEV-22970 Potential corruption */
         store_freed_or_init_rec(id, (b & 0x70) == FREE_PAGE);
+#endif
         if (UNIV_UNLIKELY(rlen != 0))
           goto record_corrupted;
         break;