mariadb/mysys/my_write.c
Venkatesh Duggirala 3932392030 BUG#11753923-SQL THREAD CRASHES ON DISK FULL
Problem:If Disk becomes full while writing into the binlog,
then the server instance hangs till someone frees the space.
After user frees up the disk space, mysql server crashes
with an assert (m_status != DA_EMPTY)

Analysis: wait_for_free_space is being called in an
infinite loop i.e., server instance will hang until
someone frees up the space. So there is no need to
set status bit in diagnostic area.

Fix: Replace my_error/my_printf_error with
sql_print_warning() which prints the warning in error log.

include/my_sys.h:
  Provision to call sql_print_warning from mysys files
mysys/errors.c:
  Replace my_error/my_printf_error with
  sql_print_warning() which prints the warning in error log.
mysys/my_error.c:
  implementation of my_printf_warning
mysys/my_write.c:
  Adding logic to break infinite loop in the simulation
sql/mysqld.cc:
  Provision to call sql_print_warning from mysys files
2013-01-02 16:31:58 +05:30

113 lines
3.5 KiB
C

/*
Copyright (c) 2000, 2001, 2004-2007 MySQL AB, 2009 Sun Microsystems, Inc.
Use is subject to license terms.
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
*/
#include "mysys_priv.h"
#include "mysys_err.h"
#include <errno.h>
/* Write a chunk of bytes to a file */
size_t my_write(int Filedes, const uchar *Buffer, size_t Count, myf MyFlags)
{
size_t writenbytes, written;
uint errors;
DBUG_ENTER("my_write");
DBUG_PRINT("my",("Fd: %d Buffer: 0x%lx Count: %lu MyFlags: %d",
Filedes, (long) Buffer, (ulong) Count, MyFlags));
errors=0; written=0;
/* The behavior of write(fd, buf, 0) is not portable */
if (unlikely(!Count))
DBUG_RETURN(0);
DBUG_EXECUTE_IF ("simulate_file_write_error_once",
{ DBUG_SET("+d,simulate_file_write_error");});
for (;;)
{
writenbytes= write(Filedes, Buffer, Count);
/**
To simulate the write error set the errno = error code
and the number pf written bytes to -1.
*/
DBUG_EXECUTE_IF ("simulate_file_write_error",
{
errno= ENOSPC;
writenbytes= (size_t) -1;
});
if (writenbytes == Count)
break;
if (writenbytes != (size_t) -1)
{ /* Safeguard */
written+=writenbytes;
Buffer+=writenbytes;
Count-=writenbytes;
}
my_errno=errno;
DBUG_PRINT("error",("Write only %ld bytes, error: %d",
(long) writenbytes, my_errno));
#ifndef NO_BACKGROUND
#ifdef THREAD
if (my_thread_var->abort)
MyFlags&= ~ MY_WAIT_IF_FULL; /* End if aborted by user */
#endif
if ((my_errno == ENOSPC || my_errno == EDQUOT) &&
(MyFlags & MY_WAIT_IF_FULL))
{
wait_for_free_space(my_filename(Filedes), errors);
errors++;
DBUG_EXECUTE_IF("simulate_file_write_error_once",
{ DBUG_SET("-d,simulate_file_write_error");});
continue;
}
if ((writenbytes == 0 || writenbytes == (size_t) -1))
{
if (my_errno == EINTR)
{
DBUG_PRINT("debug", ("my_write() was interrupted and returned %ld",
(long) writenbytes));
continue; /* Interrupted */
}
if (!writenbytes && !errors++) /* Retry once */
{
/* We may come here if the file quota is exeeded */
errno=EFBIG; /* Assume this is the error */
continue;
}
}
else
continue; /* Retry */
#endif
if (MyFlags & (MY_NABP | MY_FNABP))
{
if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
{
my_error(EE_WRITE, MYF(ME_BELL+ME_WAITTANG),
my_filename(Filedes),my_errno);
}
DBUG_RETURN(MY_FILE_ERROR); /* Error on read */
}
else
break; /* Return bytes written */
}
if (MyFlags & (MY_NABP | MY_FNABP))
DBUG_RETURN(0); /* Want only errors */
DBUG_RETURN(writenbytes+written);
} /* my_write */