WL#3072 Maria recovery

* create page cache before initializing engine and not after, because
Maria's recovery needs a page cache
* make the creation of a bitmap page more crash-resistent
* bugfix (see ma_blockrec.c)
* back to old way: create an 8k bitmap page when creating table
* preparations for the UNDO phase: recreate TRNs
* preparations for Checkpoint: list of dirty pages, testing
of rec_lsn to know if page should be skipped during Recovery
(unused in this patch as no Checkpoint module pushed yet)
* maria_chk tags repaired table with a special LSN
* reworking all around in ma_recovery.c (less duplication)


mysys/my_realloc.c:
  noted an issue in my_realloc()
sql/mysqld.cc:
  page cache needs to be created before engines are initialized,
  because Maria's initialization may do a recovery which needs
  the page cache.
storage/maria/ha_maria.cc:
  update to new prototype
storage/maria/ma_bitmap.c:
  when creating the first bitmap page we used chsize to 8192 bytes then 
  pwrite (overwrite) the last 2 bytes (8191-8192). If crash between
  the two operations, this leaves a bitmap page full without its end
  marker. A later recovery may try to read this page and find it
  exists and misses a marker and conclude it's corrupted and fail.
  Changing the chsize to only 8190 bytes: recovery will then find
  the page is too short and recreate it entirely.
storage/maria/ma_blockrec.c:
  Fix for a bug: when executing a REDO, if the data page is created,
  data_file_length was increased before _ma_bitmap_set():
  _ma_bitmap_set() called _ma_read_bitmap_page() which, due to the
  increased data_file_length, expected to find a bitmap page on disk
  with a correct end marker; if the bitmap page didn't exist already
  in fact, this failed. Fixed by increasing data_file_length only after
  _ma_read_bitmap_page() has created the new bitmap page correctly.
  This bug could happen every time a REDO is about creating a new
  bitmap page.
storage/maria/ma_check.c:
  empty data file has a bitmap page
storage/maria/ma_control_file.c:
  useless parameter to ma_control_file_create_or_open(), just
  test if this is recovery.
storage/maria/ma_control_file.h:
  new prototype
storage/maria/ma_create.c:
  Back to how it was before: maria_create() creates an 8k bitmap page.
  Thus (bugfix) data_file_length needs to reflect this instead of being 0.
storage/maria/ma_loghandler.c:
  as ma_test1 and ma_test2 now use real transactions and not
  dummy_transaction_object, REDO for INSERT/UPDATE/DELETE are always
  about real transactions, can assert this.
  A function for Recovery to assign a short id to a table.
storage/maria/ma_loghandler.h:
  new function
storage/maria/ma_loghandler_lsn.h:
  maria_chk tags repaired tables with this LSN
storage/maria/ma_open.c:
  * enforce that DMLs on transactional tables use real transactions
  and not dummy_transaction_object.
  * test if table was repaired with maria_chk (which has to been
  seen as an import of an external table into the server), test
  validity of create_rename_lsn (header corruption detection)
  * comments.
storage/maria/ma_recovery.c:
  * preparations for the UNDO phase: recreate TRNs
  * preparations for Checkpoint: list of dirty pages, testing
  of rec_lsn to know if page should be skipped during Recovery
  (unused in this patch as no Checkpoint module pushed yet)
  * reworking all around (less duplication)
storage/maria/ma_recovery.h:
  a parameter to say if the UNDO phase should be skipped
storage/maria/maria_chk.c:
  tag repaired tables with a special LSN
storage/maria/maria_read_log.c:
  * update to new prototype
  * no UNDO phase in maria_read_log for now
storage/maria/trnman.c:
  * a function for Recovery to create a transaction (TRN), needed
  in the UNDO phase
  * a function for Recovery to grab an existing transaction, needed
  in the UNDO phase (rollback all existing transactions)
storage/maria/trnman_public.h:
  new functions

storage/maria/trnman.c

@@ -18,6 +18,7 @@
 #include <my_sys.h>
 #include <m_string.h>
 #include "trnman.h"
+#include "ma_control_file.h"
 
 /*
   status variables:
@@ -708,3 +709,29 @@ end:
   pthread_mutex_unlock(&LOCK_trn_list);
   DBUG_RETURN(error);
 }
+
+
+TRN *trnman_recreate_trn_from_recovery(uint16 shortid, TrID longid)
+{
+  TrID old_trid_generator= global_trid_generator;
+  TRN *trn;
+  DBUG_ASSERT(maria_in_recovery && !maria_multi_threaded);
+  if (unlikely((trn= trnman_new_trn(NULL, NULL, NULL)) == NULL))
+    return NULL;
+  /* deallocate excessive allocations of trnman_new_trn() */
+  global_trid_generator= old_trid_generator;
+  set_if_bigger(global_trid_generator, longid);
+  short_trid_to_active_trn[trn->short_id]= 0;
+  DBUG_ASSERT(short_trid_to_active_trn[shortid] == NULL);
+  short_trid_to_active_trn[shortid]= trn;
+  trn->trid= longid;
+  trn->short_id= shortid;
+  return trn;
+}
+
+
+TRN *trnman_get_any_trn()
+{
+  TRN *trn= active_list_min.next;
+  return (trn != &active_list_max) ? trn : NULL;
+}