WL#3072 Maria Recovery

- new program maria_read_log to display and apply log records
found in a Maria log (see file's revision comment)
- minor, misc fixes


storage/maria/Makefile.am:
  new program maria_read_log
storage/maria/ha_maria.cc:
  create control file if missing
storage/maria/ma_blockrec.c:
  0 -> LSN_IMPOSSIBLE; comments
storage/maria/ma_checkpoint.h:
  preparations for Checkpoint module
storage/maria/ma_close.c:
  comment
storage/maria/ma_control_file.c:
  renaming constants.
  Possibility to say "open control file but don't create it if it's
  missing" (used by maria_read_log which does not want to create
  anything)
storage/maria/ma_control_file.h:
  renaming constants
storage/maria/ma_create.c:
  I had duplicated "linkname" and "linkname_ptr", now I see it's not
  needed, reverting. Indeed those variables don't contain interesting
  information; fixing log record accordingly (the links are in
  ci->data/index_file_name). Storing keystart in log record is needed,
  to know at which size we must extend the file if we replay
  LOGREC_CREATE_TABLE.
storage/maria/ma_loghandler.c:
  some structures need to be known to maria_read_log.c, taking
  them to ma_loghandler.h
storage/maria/ma_loghandler.h:
  we have page_store, adding page_korr.
  translog_lock() made public, because Checkpoint will need it (to
  write to control file).
  Some structures moved from ma_loghandler.c because maria_read_log.c
  needs them (needs to know the execute-in-REDO-phase hooks of each
  record).
storage/maria/ma_loghandler_lsn.h:
  constants defined in ma_control_file.h serve everywhere,
  and they relate to LSNs, so putting them in ma_loghandler_lsn.h.
  Stronger constraints in LSN_VALID().
storage/maria/ma_pagecache.c:
  renaming constants
storage/maria/ma_recovery.h:
  copyright
storage/maria/ma_test1.c:
  new prototype
storage/maria/ma_test2.c:
  new prototype
storage/maria/trnman_public.h:
  double-inclusion safe
storage/maria/unittest/ma_control_file-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler_multigroup-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler_multithread-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler_pagecache-t.c:
  constants renamed, new prototype
storage/myisam/mi_close.c:
  comment
storage/maria/maria_read_log.c:
  program to read and print log records from a Maria transaction log,
  and optionally apply them to tables. Very basic, early version.
  Should serve as a base for Recovery's code. Designed to be idempotent.
  Create a log by running maria.test, then cd to var/master-data
  and run "maria_read_log --only-display" to see info about records;
  run "maria_read_log --display-and-apply" to also apply the records
  to tables (it's more interesting if you first wipe out the
  tables in var/master-data/test, to see how they get re-created).
  Only a few records are handled by now: LONG_TRANSACTION_ID,
  COMMIT, FILE_ID, REDO_CREATE_TABLE; place is ready for
  REDO_INSERT_ROW_HEAD where I could use Monty's help (search for
  "Monty" in the file). Note: changes to the index pages, index's header
  and bitmap pages are not properly logged yet, so don't expect
  the program to work with that.

storage/maria/ma_control_file.c

@@ -40,15 +40,9 @@
 #define CONTROL_FILE_FILENO_SIZE 4
 #define CONTROL_FILE_SIZE (CONTROL_FILE_FILENO_OFFSET + CONTROL_FILE_FILENO_SIZE)
 
-/*
-  This module owns these two vars.
-  uint32 is always atomically updated, but LSN is 8 bytes, we will need
-  provisions to ensure that it's updated atomically in
-  ma_control_file_write_and_force(). Probably the log mutex could be
-  used. TODO.
-*/
-LSN last_checkpoint_lsn;
-uint32 last_logno;
+/* This module owns these two vars. */
+LSN    last_checkpoint_lsn= LSN_IMPOSSIBLE;
+uint32 last_logno=          FILENO_IMPOSSIBLE;
 
 /**
    @brief If log's lock should be asserted when writing to control file.
@@ -65,16 +59,16 @@ my_bool maria_multi_threaded= FALSE;
 static int control_file_fd= -1;
 
 /*
-  Initialize control file subsystem
+  @brief Initialize control file subsystem
 
-  SYNOPSIS
-    ma_control_file_create_or_open()
-
-  Looks for the control file. If absent, it's a fresh start, creates file.
+  Looks for the control file. If none and creation is requested, creates file.
   If present, reads it to find out last checkpoint's LSN and last log, updates
   the last_checkpoint_lsn and last_logno global variables.
   Called at engine's start.
 
+  @param  create_if_missing
+
+  @note
   The format of the control file is:
   4 bytes: magic string
   4 bytes: checksum of the following bytes
@@ -82,11 +76,11 @@ static int control_file_fd= -1;
   4 bytes: offset in log where last checkpoint is
   4 bytes: number of last log
 
-  RETURN
-    0 - OK
-    1 - Error (in which case the file is left closed)
+  @return Operation status
+    @retval 0      OK
+    @retval 1      Error (in which case the file is left closed)
 */
-CONTROL_FILE_ERROR ma_control_file_create_or_open()
+CONTROL_FILE_ERROR ma_control_file_create_or_open(my_bool create_if_missing)
 {
   char buffer[CONTROL_FILE_SIZE];
   char name[FN_REFLEN];
@@ -115,6 +109,8 @@ CONTROL_FILE_ERROR ma_control_file_create_or_open()
 
   if (create_file)
   {
+    if (!create_if_missing)
+      DBUG_RETURN(CONTROL_FILE_MISSING);
     if ((control_file_fd= my_create(name, 0,
                                     open_flags, MYF(MY_SYNC_DIR))) < 0)
       DBUG_RETURN(CONTROL_FILE_UNKNOWN_ERROR);
@@ -136,8 +132,8 @@ CONTROL_FILE_ERROR ma_control_file_create_or_open()
     */
 
     /* init the file with these "undefined" values */
-    DBUG_RETURN(ma_control_file_write_and_force(CONTROL_FILE_IMPOSSIBLE_LSN,
-                                                CONTROL_FILE_IMPOSSIBLE_FILENO,
+    DBUG_RETURN(ma_control_file_write_and_force(LSN_IMPOSSIBLE,
+                                                FILENO_IMPOSSIBLE,
                                                 CONTROL_FILE_UPDATE_ALL));
   }
 
@@ -315,8 +311,8 @@ int ma_control_file_end()
     As this module owns these variables, closing the module forbids access to
     them (just a safety):
   */
-  last_checkpoint_lsn= CONTROL_FILE_IMPOSSIBLE_LSN;
-  last_logno= CONTROL_FILE_IMPOSSIBLE_FILENO;
+  last_checkpoint_lsn= LSN_IMPOSSIBLE;
+  last_logno= FILENO_IMPOSSIBLE;
 
   DBUG_RETURN(close_error);
 }