mariadb/mysys/my_pread.c
He Zhenxing 82fc35475c BUG#22082 Slave hangs(holds mutex) on "disk full"
When disk is full, server may waiting for free space while
writing binlog, relay-log or MyISAM tables. The server will 
continue after user have freed some space. But the error
message printed was not quite clear about the how often the
error message is printed, and there will be a delay before
the server continue and user freeing space. And caused users
thinking that the server was hanging forever.

This patch fixed the problem by making the error messages
printed more clear. The error message is split into two part,
the first part will only be printed once, and the second part
will be printed very 10 times.

Message first part:
Disk is full writing '<filename>' (Errcode: <errorno>). Waiting
for someone to free space... (Expect up to 60 secs delay for 
server to continue after freeing disk space)

Message second part:
Retry in 60 secs, Message reprinted in 600 secs
2009-03-06 17:32:00 +08:00

147 lines
4.6 KiB
C

/* Copyright (C) 2000 MySQL AB
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 */
#include "mysys_priv.h"
#include "mysys_err.h"
#include <errno.h>
#ifdef HAVE_PREAD
#include <unistd.h>
#endif
/* Read a chunk of bytes from a file */
uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
myf MyFlags)
{
uint readbytes;
int error;
DBUG_ENTER("my_pread");
DBUG_PRINT("my",("Fd: %d Seek: %lu Buffer: 0x%lx Count: %u MyFlags: %d",
Filedes, (ulong) offset, (long) Buffer, Count, MyFlags));
for (;;)
{
#ifndef __WIN__
errno=0; /* Linux doesn't reset this */
#endif
#ifndef HAVE_PREAD
pthread_mutex_lock(&my_file_info[Filedes].mutex);
readbytes= (uint) -1;
error= (lseek(Filedes, offset, MY_SEEK_SET) == -1L ||
(readbytes = (uint) read(Filedes, Buffer, Count)) != Count);
pthread_mutex_unlock(&my_file_info[Filedes].mutex);
#else
error=((readbytes = (uint) pread(Filedes, Buffer, Count, offset)) != Count);
#endif
if (error)
{
my_errno=errno;
DBUG_PRINT("warning",("Read only %d bytes off %u from %d, errno: %d",
(int) readbytes, Count,Filedes,my_errno));
#ifdef THREAD
if ((readbytes == 0 || (int) readbytes == -1) && errno == EINTR)
{
DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d",
(int) readbytes));
continue; /* Interrupted */
}
#endif
if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
{
if ((int) readbytes == -1)
my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
my_filename(Filedes),my_errno);
else if (MyFlags & (MY_NABP | MY_FNABP))
my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
my_filename(Filedes),my_errno);
}
if ((int) readbytes == -1 || (MyFlags & (MY_FNABP | MY_NABP)))
DBUG_RETURN(MY_FILE_ERROR); /* Return with error */
}
if (MyFlags & (MY_NABP | MY_FNABP))
DBUG_RETURN(0); /* Read went ok; Return 0 */
DBUG_RETURN(readbytes); /* purecov: inspected */
}
} /* my_pread */
/* Write a chunk of bytes to a file */
uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset,
myf MyFlags)
{
uint writenbytes,errors;
ulong written;
DBUG_ENTER("my_pwrite");
DBUG_PRINT("my",("Fd: %d Seek: %lu Buffer: 0x%lx Count: %d MyFlags: %d",
Filedes, (ulong) offset, (long) Buffer, Count, MyFlags));
errors=0; written=0L;
for (;;)
{
#ifndef HAVE_PREAD
int error;
writenbytes= (uint) -1;
pthread_mutex_lock(&my_file_info[Filedes].mutex);
error=(lseek(Filedes, offset, MY_SEEK_SET) != -1L &&
(writenbytes = (uint) write(Filedes, Buffer, Count)) == Count);
pthread_mutex_unlock(&my_file_info[Filedes].mutex);
if (error)
break;
#else
if ((writenbytes = (uint) pwrite(Filedes, Buffer, Count,offset)) == Count)
break;
#endif
if ((int) writenbytes != -1)
{ /* Safegueard */
written+=writenbytes;
Buffer+=writenbytes;
Count-=writenbytes;
offset+=writenbytes;
}
my_errno=errno;
DBUG_PRINT("error",("Write only %d bytes",writenbytes));
#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++;
continue;
}
if ((writenbytes > 0 && (uint) writenbytes != (uint) -1) ||
my_errno == EINTR)
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); /* purecov: inspected */
} /* my_pwrite */