mariadb/mysys/my_sync.c
Vladislav Vaintroub 4e92af9f43 This is the downport of
Bug#24509 - 2048 file descriptor limit on windows needs increasing, also 
WL#3049 - improved Windows I/O
                        
The patch replaces the use of the POSIX I/O interfaces in mysys on Windows with 
the Win32 API calls (CreateFile, WriteFile, etc). The Windows HANDLE for the open 
file is stored in the my_file_info struct, along with a flag for append mode 
because the Windows API does not support opening files in append mode in all cases)
The default max open files has been increased to 16384 and can be increased further
by setting --max-open-files=<value> during the server start.
                              
Another major change in this patch that almost all Windows specific file IO code
has been moved to a new file my_winfile.c, greatly reducing the amount of code 
in #ifdef blocks within mysys, thus improving readability.
                               
                                    
Minor enhancements:
- my_(f)stat() is changed to use __stati64 structure with  64 file size
and timestamps. It will return correct file size now (C runtime implementation
used to report outdated information)
- my_lock on Windows is prepared to handle additional timeout parameter
- after review : changed __WIN__ to _WIN32 in the new and changed code.
2009-09-11 22:26:35 +02:00

155 lines
4.1 KiB
C

/* Copyright (C) 2003 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>
/*
Sync data in file to disk
SYNOPSIS
my_sync()
fd File descritor to sync
my_flags Flags (now only MY_WME is supported)
NOTE
If file system supports its, only file data is synced, not inode data.
MY_IGNORE_BADFD is useful when fd is "volatile" - not protected by a
mutex. In this case by the time of fsync(), fd may be already closed by
another thread, or even reassigned to a different file. With this flag -
MY_IGNORE_BADFD - such a situation will not be considered an error.
(which is correct behaviour, if we know that the other thread synced the
file before closing)
RETURN
0 ok
-1 error
*/
int my_sync(File fd, myf my_flags)
{
int res;
DBUG_ENTER("my_sync");
DBUG_PRINT("my",("Fd: %d my_flags: %d", fd, my_flags));
do
{
#if defined(F_FULLFSYNC)
/*
In Mac OS X >= 10.3 this call is safer than fsync() (it forces the
disk's cache and guarantees ordered writes).
*/
if (!(res= fcntl(fd, F_FULLFSYNC, 0)))
break; /* ok */
/* Some file systems don't support F_FULLFSYNC and fail above: */
DBUG_PRINT("info",("fcntl(F_FULLFSYNC) failed, falling back"));
#endif
#if defined(HAVE_FDATASYNC)
res= fdatasync(fd);
#elif defined(HAVE_FSYNC)
res= fsync(fd);
#elif defined(_WIN32)
res= my_win_fsync(fd);
#else
#error Cannot find a way to sync a file, durability in danger
res= 0; /* No sync (strange OS) */
#endif
} while (res == -1 && errno == EINTR);
if (res)
{
int er= errno;
if (!(my_errno= er))
my_errno= -1; /* Unknown error */
if ((my_flags & MY_IGNORE_BADFD) &&
(er == EBADF || er == EINVAL || er == EROFS))
{
DBUG_PRINT("info", ("ignoring errno %d", er));
res= 0;
}
else if (my_flags & MY_WME)
my_error(EE_SYNC, MYF(ME_BELL+ME_WAITTANG), my_filename(fd), my_errno);
}
DBUG_RETURN(res);
} /* my_sync */
static const char cur_dir_name[]= {FN_CURLIB, 0};
/*
Force directory information to disk.
SYNOPSIS
my_sync_dir()
dir_name the name of the directory
my_flags flags (MY_WME etc)
RETURN
0 if ok, !=0 if error
*/
int my_sync_dir(const char *dir_name, myf my_flags)
{
#ifdef NEED_EXPLICIT_SYNC_DIR
DBUG_ENTER("my_sync_dir");
DBUG_PRINT("my",("Dir: '%s' my_flags: %d", dir_name, my_flags));
File dir_fd;
int res= 0;
const char *correct_dir_name;
/* Sometimes the path does not contain an explicit directory */
correct_dir_name= (dir_name[0] == 0) ? cur_dir_name : dir_name;
/*
Syncing a dir may give EINVAL on tmpfs on Linux, which is ok.
EIO on the other hand is very important. Hence MY_IGNORE_BADFD.
*/
if ((dir_fd= my_open(correct_dir_name, O_RDONLY, MYF(my_flags))) >= 0)
{
if (my_sync(dir_fd, MYF(my_flags | MY_IGNORE_BADFD)))
res= 2;
if (my_close(dir_fd, MYF(my_flags)))
res= 3;
}
else
res= 1;
DBUG_RETURN(res);
#else
return 0;
#endif
}
/*
Force directory information to disk.
SYNOPSIS
my_sync_dir_by_file()
file_name the name of a file in the directory
my_flags flags (MY_WME etc)
RETURN
0 if ok, !=0 if error
*/
int my_sync_dir_by_file(const char *file_name, myf my_flags)
{
#ifdef NEED_EXPLICIT_SYNC_DIR
char dir_name[FN_REFLEN];
size_t dir_name_length;
dirname_part(dir_name, file_name, &dir_name_length);
return my_sync_dir(dir_name, my_flags);
#else
return 0;
#endif
}