Bug #26043363 - CRASH INNMEM::TABLE::INSERT AT INNMEM/SRC/TABLE.CC:85

Ftruncate isn't reserving disk space for file with only 0s inside, so following writes to mmaped pages are allocating new disk pages and on out of space the SIGBUS is being thrown.
Function my_chsize uses ftruncate, we want to use posix_fallocate, hence implementation of my_fallocator based on my_chsize.

RB#16345
Reviewed by Sunny Bains and Thayumanavar X Sachithanantha

Author: Elżbieta Babij

include/my_sys.h

@@ -651,6 +651,7 @@ extern FILE *my_freopen(const char *path, const char *mode, FILE *stream);
 extern int my_fclose(FILE *fd,myf MyFlags);
 extern File my_fileno(FILE *fd);
 extern int my_chsize(File fd,my_off_t newlength, int filler, myf MyFlags);
+extern int my_fallocator(File fd, my_off_t newlength, int filler, myf MyFlags);
 extern void thr_set_sync_wait_callback(void (*before_sync)(void),
                                        void (*after_sync)(void));
 extern int my_sync(File fd, myf my_flags);

mysys/CMakeLists.txt

@@ -59,6 +59,7 @@ SET(MYSYS_SOURCES
   my_delete.cc
   my_div.cc
   my_error.cc
+  my_fallocator.cc
   my_file.cc
   my_fopen.cc
   my_fstream.cc

mysys/my_fallocator.cc

@@ -0,0 +1,122 @@
+/* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+
+   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+/**
+  @file mysys/my_fallocator.cc
+*/
+
+#include "my_config.h"
+
+#include <errno.h>
+#ifdef HAVE_POSIX_FALLOCATE
+#include <fcntl.h>
+#endif
+#include <string.h>
+#include <sys/types.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "my_dbug.h"
+#include "my_inttypes.h"
+#include "my_io.h"
+#include "my_sys.h"
+#include "my_thread_local.h"
+#include "mysys_err.h"
+#ifdef _WIN32
+#include "mysys_priv.h"
+#endif
+
+/** Change size of the specified file. Forces the OS to reserve disk space for
+the file, even when called to fill with zeros. he function also changes the
+file position. Usually it points to the end of the file after execution.
+
+@note Implementation based on, and mostly copied from, my_chsize. But instead
+of ftruncate uses posix_fallocate. This implementation was needed because of
+allocation in temptable. Probably this implementation should replace my_chsize
+implementation.
+
+@param[in] fd File descriptor
+@param[in] new_length New file size
+@param[in] filler Fill up all bytes after new_length with this character
+@param[in] MyFlags Flags
+@return 0 if OK, 1 otherwise
+*/
+int my_fallocator(File fd, my_off_t newlength, int filler, myf MyFlags)
+{
+  my_off_t oldsize;
+  uchar buff[IO_SIZE];
+  DBUG_ENTER("my_fallocator");
+  DBUG_PRINT("my",("fd: %d  length: %lu  MyFlags: %d", fd, (ulong) newlength,
+    MyFlags));
+
+  if ((oldsize = my_seek(fd, 0L, MY_SEEK_END, MYF(MY_WME + MY_FAE)))
+    == newlength)
+    DBUG_RETURN(0);
+
+  DBUG_PRINT("info",("old_size: %ld", (ulong) oldsize));
+
+  if (oldsize > newlength)
+  {
+#ifdef _WIN32
+    if (my_win_chsize(fd, newlength))
+    {
+      set_my_errno(errno);
+      goto err;
+    }
+    DBUG_RETURN(0);
+#elif defined(HAVE_POSIX_FALLOCATE)
+    if (posix_fallocate(fd, 0, (off_t) newlength) != 0)
+    {
+      set_my_errno(errno);
+      goto err;
+    }
+    DBUG_RETURN(0);
+#else
+    /*
+    Fill space between requested length and true length with 'filler'
+    We should never come here on any modern machine
+    */
+    if (my_seek(fd, newlength, MY_SEEK_SET, MYF(MY_WME + MY_FAE))
+      == MY_FILEPOS_ERROR)
+    {
+      goto err;
+    }
+    std::swap(newlength, oldsize);
+#endif //WIN32
+  }
+
+  /* Full file with 'filler' until it's as big as requested */
+  memset(buff, filler, IO_SIZE);
+  while (newlength - oldsize > IO_SIZE)
+  {
+    if (my_write(fd, buff, IO_SIZE, MYF(MY_NABP)))
+      goto err;
+    oldsize+= IO_SIZE;
+  }
+  if (my_write(fd,buff,(size_t) (newlength - oldsize), MYF(MY_NABP)))
+    goto err;
+  DBUG_RETURN(0);
+
+err:
+  DBUG_PRINT("error", ("errno: %d", errno));
+  if (MyFlags & MY_WME)
+  {
+    char  errbuf[MYSYS_STRERROR_SIZE];
+    my_error(EE_CANT_CHSIZE, MYF(0),
+      my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno()));
+  }
+  DBUG_RETURN(1);
+} /* my_fallocator */

storage/temptable/include/temptable/allocator.h

@@ -738,19 +738,12 @@ inline void* Allocator<T>::mem_fetch_from_disk(size_t bytes) {
     return nullptr;
   }
 
-#ifdef HAVE_FTRUNCATE
-  if (ftruncate(f, bytes) != 0) {
-    my_close(f, MYF(MY_WME));
-    return nullptr;
-  }
-#else
   /* This will write `bytes` 0x0 bytes to the file on disk. */
-  if (my_chsize(f, bytes, 0x0, MYF(MY_WME)) != 0 ||
+  if (my_fallocator(f, bytes, 0x0, MYF(MY_WME)) != 0 ||
       my_seek(f, 0, MY_SEEK_SET, MYF(MY_WME)) == MY_FILEPOS_ERROR) {
     my_close(f, MYF(MY_WME));
     return nullptr;
   }
-#endif
 
   void* ptr = my_mmap(nullptr, bytes, PROT_READ | PROT_WRITE, MAP_SHARED, f, 0);