Fixed ability to read without read lock acquiring. (BUG#39665 related)

storage/maria/ma_pagecache.c:
  Fixed ability to read without read lock acquiring.
storage/maria/unittest/CMakeLists.txt:
  New unit test which tests simple read and prolonged writes consistency added.
storage/maria/unittest/Makefile.am:
  New unit test which tests simple read and prolonged writes consistency added.
storage/maria/unittest/ma_pagecache_rwconsist2.c:
  New unit test which tests simple read and prolonged writes consistency added.

storage/maria/unittest/CMakeLists.txt

@@ -94,3 +94,5 @@ SET_TARGET_PROPERTIES(ma_pagecache_consist_64kWR-t
 	PROPERTIES COMPILE_FLAGS "${ma_pagecache_common_cppflags} -DTEST_PAGE_SIZE=65536 -DTEST_WRITERS")
 ADD_EXECUTABLE(ma_pagecache_rwconsist_1k-t ma_pagecache_rwconsist.c)
 SET_TARGET_PROPERTIES(ma_pagecache_rwconsist_1k-t PROPERTIES COMPILE_FLAGS "-DTEST_PAGE_SIZE=1024")
+ADD_EXECUTABLE(ma_pagecache_rwconsist2_1k-t ma_pagecache_rwconsist2.c)
+SET_TARGET_PROPERTIES(ma_pagecache_rwconsist2_1k-t PROPERTIES COMPILE_FLAGS "-DTEST_PAGE_SIZE=1024")

storage/maria/unittest/Makefile.am

@@ -39,6 +39,7 @@ noinst_PROGRAMS =	ma_control_file-t trnman-t \
 			ma_pagecache_consist_1kWR-t \
 			ma_pagecache_consist_64kWR-t \
                         ma_pagecache_rwconsist_1k-t \
+                        ma_pagecache_rwconsist2_1k-t \
 			ma_test_loghandler-t \
                         ma_test_loghandler_multigroup-t \
 			ma_test_loghandler_multithread-t \
@@ -101,6 +102,8 @@ ma_pagecache_consist_64kWR_t_CPPFLAGS =	$(ma_pagecache_common_cppflags) -DTEST_P
 
 ma_pagecache_rwconsist_1k_t_SOURCES =	ma_pagecache_rwconsist.c
 ma_pagecache_rwconsist_1k_t_CPPFLAGS = -DTEST_PAGE_SIZE=1024
+ma_pagecache_rwconsist2_1k_t_SOURCES =	ma_pagecache_rwconsist2.c
+ma_pagecache_rwconsist2_1k_t_CPPFLAGS = -DTEST_PAGE_SIZE=1024
 
 # the generic lock manager may not be used in the end and lockman1-t crashes,
 # and lockman2-t takes at least quarter an hour,

storage/maria/unittest/ma_pagecache_rwconsist2.c

+/* Copyright (C) 2006-2008 MySQL AB, 2008 Sun Microsystems, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+
+/**
+  @file this unit tests consistence of  long block writing under write lock
+  and simultaneous reading of this block with read request without read lock
+  requirement.
+*/
+
+/*
+  TODO: use pthread_join instead of wait_for_thread_count_to_be_zero, like in
+  my_atomic-t.c (see BUG#22320).
+*/
+
+#include <tap.h>
+#include <my_sys.h>
+#include <m_string.h>
+#include "test_file.h"
+#include <tap.h>
+
+#define PCACHE_SIZE (TEST_PAGE_SIZE*1024*8)
+
+#ifndef DBUG_OFF
+static const char* default_dbug_option;
+#endif
+
+
+#define SLEEP my_sleep(5)
+
+static char *file1_name= (char*)"page_cache_test_file_1";
+static PAGECACHE_FILE file1;
+static pthread_cond_t COND_thread_count;
+static pthread_mutex_t LOCK_thread_count;
+static uint thread_count= 0;
+static PAGECACHE pagecache;
+
+static uint number_of_readers= 5;
+static uint number_of_writers= 5;
+static uint number_of_read_tests= 20000;
+static uint number_of_write_tests= 1000;
+static uint report_divisor= 50;
+
+/**
+  @brief Dummy pagecache callback.
+*/
+
+static my_bool
+dummy_callback(uchar *page __attribute__((unused)),
+               pgcache_page_no_t page_no __attribute__((unused)),
+               uchar* data_ptr __attribute__((unused)))
+{
+  return 0;
+}
+
+
+/**
+  @brief Dummy pagecache callback.
+*/
+
+static void
+dummy_fail_callback(uchar* data_ptr __attribute__((unused)))
+{
+  return;
+}
+
+
+/**
+  @brief Checks page consistency
+
+  @param buff            pointer to the page content
+  @param task            task ID
+*/
+void check_page(uchar *buff, int task)
+{
+  uint i;
+  DBUG_ENTER("check_page");
+
+  for (i= 1; i < TEST_PAGE_SIZE; i++)
+  {
+    if (buff[0] != buff[i])
+      goto err;
+  }
+  DBUG_VOID_RETURN;
+err:
+  diag("Task %d char #%u '%u' != '%u'", task, i, (uint) buff[0],
+       (uint) buff[i]);
+  DBUG_PRINT("err", ("try to flush"));
+  exit(1);
+}
+
+
+
+void reader(int num)
+{
+  unsigned char buff[TEST_PAGE_SIZE];
+  uint i;
+
+  for (i= 0; i < number_of_read_tests; i++)
+  {
+    if (i % report_divisor == 0)
+      diag("Reader %d - %u", num, i);
+    pagecache_read(&pagecache, &file1, 0, 3, buff,
+                   PAGECACHE_PLAIN_PAGE,
+                   PAGECACHE_LOCK_LEFT_UNLOCKED,
+                   NULL);
+    check_page(buff, num);
+  }
+}
+
+
+void writer(int num)
+{
+  uint i;
+  uchar *buff;
+  PAGECACHE_BLOCK_LINK *link;
+
+  for (i= 0; i < number_of_write_tests; i++)
+  {
+    uchar c= (uchar) rand() % 256;
+
+    if (i % report_divisor == 0)
+      diag("Writer %d - %u", num, i);
+    buff= pagecache_read(&pagecache, &file1, 0, 3, NULL,
+                         PAGECACHE_PLAIN_PAGE,
+                         PAGECACHE_LOCK_WRITE,
+                         &link);
+
+    check_page(buff, num);
+    bfill(buff, TEST_PAGE_SIZE / 2, c);
+    SLEEP;
+    bfill(buff + TEST_PAGE_SIZE/2, TEST_PAGE_SIZE / 2, c);
+    check_page(buff, num);
+    pagecache_unlock_by_link(&pagecache, link,
+                             PAGECACHE_LOCK_WRITE_UNLOCK,
+                             PAGECACHE_UNPIN, 0, 0, 1, FALSE);
+    SLEEP;
+  }
+}
+
+
+static void *test_thread_reader(void *arg)
+{
+  int param=*((int*) arg);
+  my_thread_init();
+  {
+    DBUG_ENTER("test_reader");
+
+    DBUG_PRINT("enter", ("param: %d", param));
+
+    reader(param);
+
+    DBUG_PRINT("info", ("Thread %s ended", my_thread_name()));
+    pthread_mutex_lock(&LOCK_thread_count);
+    ok(1, "reader%d: done", param);
+    thread_count--;
+    VOID(pthread_cond_signal(&COND_thread_count)); /* Tell main we are ready */
+    pthread_mutex_unlock(&LOCK_thread_count);
+    free((uchar*) arg);
+    my_thread_end();
+  }
+  return 0;
+}
+
+
+static void *test_thread_writer(void *arg)
+{
+  int param=*((int*) arg);
+  my_thread_init();
+  {
+    DBUG_ENTER("test_writer");
+
+    writer(param);
+
+    DBUG_PRINT("info", ("Thread %s ended", my_thread_name()));
+    pthread_mutex_lock(&LOCK_thread_count);
+    ok(1, "writer%d: done", param);
+    thread_count--;
+    VOID(pthread_cond_signal(&COND_thread_count)); /* Tell main we are ready */
+    pthread_mutex_unlock(&LOCK_thread_count);
+    free((uchar*) arg);
+    my_thread_end();
+  }
+  return 0;
+}
+
+
+int main(int argc __attribute__((unused)),
+         char **argv __attribute__((unused)))
+{
+  pthread_t tid;
+  pthread_attr_t thr_attr;
+  int *param, error, pagen;
+
+  MY_INIT(argv[0]);
+
+#ifndef DBUG_OFF
+#if defined(__WIN__)
+  default_dbug_option= "d:t:i:O,\\test_pagecache_consist.trace";
+#else
+  default_dbug_option= "d:t:i:O,/tmp/test_pagecache_consist.trace";
+#endif
+  if (argc > 1)
+  {
+    DBUG_SET(default_dbug_option);
+    DBUG_SET_INITIAL(default_dbug_option);
+  }
+#endif
+
+  {
+  DBUG_ENTER("main");
+  DBUG_PRINT("info", ("Main thread: %s\n", my_thread_name()));
+  plan(number_of_writers + number_of_readers);
+  SKIP_BIG_TESTS(number_of_writers + number_of_readers)
+  {
+
+  if ((file1.file= my_open(file1_name,
+                           O_CREAT | O_TRUNC | O_RDWR, MYF(0))) == -1)
+  {
+    diag( "Got error during file1 creation from open() (errno: %d)\n",
+	    errno);
+    exit(1);
+  }
+  pagecache_file_init(file1, &dummy_callback, &dummy_callback,
+                      &dummy_fail_callback, &dummy_callback, NULL);
+  DBUG_PRINT("info", ("file1: %d", file1.file));
+  if (my_chmod(file1_name, S_IRWXU | S_IRWXG | S_IRWXO, MYF(MY_WME)))
+    exit(1);
+  my_pwrite(file1.file, (const uchar*) "test file", 9, 0, MYF(0));
+
+  if ((error= pthread_cond_init(&COND_thread_count, NULL)))
+  {
+    diag( "COND_thread_count: %d from pthread_cond_init (errno: %d)\n",
+	    error, errno);
+    exit(1);
+  }
+  if ((error= pthread_mutex_init(&LOCK_thread_count, MY_MUTEX_INIT_FAST)))
+  {
+    diag( "LOCK_thread_count: %d from pthread_cond_init (errno: %d)\n",
+	    error, errno);
+    exit(1);
+  }
+
+  if ((error= pthread_attr_init(&thr_attr)))
+  {
+    diag("Got error: %d from pthread_attr_init (errno: %d)\n",
+	    error,errno);
+    exit(1);
+  }
+  if ((error= pthread_attr_setdetachstate(&thr_attr, PTHREAD_CREATE_DETACHED)))
+  {
+    diag(
+	    "Got error: %d from pthread_attr_setdetachstate (errno: %d)\n",
+	    error,errno);
+    exit(1);
+  }
+
+#ifdef HAVE_THR_SETCONCURRENCY
+  VOID(thr_setconcurrency(2));
+#endif
+
+  if ((pagen= init_pagecache(&pagecache, PCACHE_SIZE, 0, 0,
+                             TEST_PAGE_SIZE, 0)) == 0)
+  {
+    diag("Got error: init_pagecache() (errno: %d)\n",
+            errno);
+    exit(1);
+  }
+  DBUG_PRINT("info", ("Page cache %d pages", pagen));
+  {
+    unsigned char *buffr= malloc(TEST_PAGE_SIZE);
+    memset(buffr, '\0', TEST_PAGE_SIZE);
+    pagecache_write(&pagecache, &file1, 0, 3, buffr,
+                    PAGECACHE_PLAIN_PAGE,
+                    PAGECACHE_LOCK_LEFT_UNLOCKED,
+                    PAGECACHE_PIN_LEFT_UNPINNED,
+                    PAGECACHE_WRITE_DELAY,
+                    0, LSN_IMPOSSIBLE);
+  }
+  pthread_mutex_lock(&LOCK_thread_count);
+
+  while (number_of_readers != 0 || number_of_writers != 0)
+  {
+    if (number_of_readers != 0)
+    {
+      param=(int*) malloc(sizeof(int));
+      *param= number_of_readers + number_of_writers;
+      if ((error= pthread_create(&tid, &thr_attr, test_thread_reader,
+                                 (void*) param)))
+      {
+        diag("Got error: %d from pthread_create (errno: %d)\n",
+                error,errno);
+        exit(1);
+      }
+      thread_count++;
+      number_of_readers--;
+    }
+    if (number_of_writers != 0)
+    {
+      param=(int*) malloc(sizeof(int));
+      *param= number_of_writers + number_of_readers;
+      if ((error= pthread_create(&tid, &thr_attr, test_thread_writer,
+                                 (void*) param)))
+      {
+        diag("Got error: %d from pthread_create (errno: %d)\n",
+                error,errno);
+        exit(1);
+      }
+      thread_count++;
+      number_of_writers--;
+    }
+  }
+  DBUG_PRINT("info", ("Thread started"));
+  pthread_mutex_unlock(&LOCK_thread_count);
+
+  pthread_attr_destroy(&thr_attr);
+
+  /* wait finishing */
+  pthread_mutex_lock(&LOCK_thread_count);
+  while (thread_count)
+  {
+    if ((error= pthread_cond_wait(&COND_thread_count, &LOCK_thread_count)))
+      diag("COND_thread_count: %d from pthread_cond_wait\n", error);
+  }
+  pthread_mutex_unlock(&LOCK_thread_count);
+  DBUG_PRINT("info", ("thread ended"));
+
+  end_pagecache(&pagecache, 1);
+  DBUG_PRINT("info", ("Page cache ended"));
+
+  if (my_close(file1.file, MYF(0)) != 0)
+  {
+    diag( "Got error during file1 closing from close() (errno: %d)\n",
+	    errno);
+    exit(1);
+  }
+  my_delete(file1_name, MYF(0));
+
+  DBUG_PRINT("info", ("file1 (%d) closed", file1.file));
+  DBUG_PRINT("info", ("Program end"));
+  } /* SKIP_BIG_TESTS */
+  my_end(0);
+
+  return exit_status();
+  }
+}