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/*
Copyright (c) 2003, 2011, Oracle and/or its affiliates
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 02110-1335 USA */
#include "mysys_priv.h"
#include "mysys_err.h"
#include <errno.h>
ulong my_sync_count; /* Count number of sync calls */
static void (*before_sync_wait)(void)= 0;
static void (*after_sync_wait)(void)= 0;
void thr_set_sync_wait_callback(void (*before_wait)(void),
void (*after_wait)(void))
{
before_sync_wait= before_wait;
after_sync_wait= after_wait;
}
/*
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)
MY_SYNC_FILESIZE is useful when syncing a file after it has been extended.
On Linux, fdatasync() on ext3/ext4 file systems does not properly flush
to disk the inode data required to preserve the added data across a crash
(this looks to be a bug). But when a file is extended, inode data will most
likely need flushing in any case, so passing MY_SYNC_FILESIZE as flags
is not likely to be any slower, and will be crash safe on Linux ext3/ext4.
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: %lu", fd, my_flags));
if (my_disable_sync)
DBUG_RETURN(0);
statistic_increment(my_sync_count,&THR_LOCK_open);
if (before_sync_wait)
(*before_sync_wait)();
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) && HAVE_DECL_FDATASYNC
if (!(my_flags & MY_SYNC_FILESIZE))
res= fdatasync(fd);
else
{
#endif
#if defined(HAVE_FSYNC)
res= fsync(fd);
if (res == -1 && errno == ENOLCK)
res= 0; /* Result Bug in Old FreeBSD */
#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
#if defined(HAVE_FDATASYNC) && HAVE_DECL_FDATASYNC
}
#endif
} while (res == -1 && errno == EINTR);
if (res)
{
int er= errno;
if (!(my_errno= er))
my_errno= -1; /* Unknown error */
if (after_sync_wait)
(*after_sync_wait)();
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), my_filename(fd), my_errno);
}
else
{
if (after_sync_wait)
(*after_sync_wait)();
}
DBUG_RETURN(res);
} /* my_sync */
/*
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 __attribute__((unused)),
myf my_flags __attribute__((unused)))
{
#ifdef NEED_EXPLICIT_SYNC_DIR
static const char cur_dir_name[]= {FN_CURLIB, 0};
File dir_fd;
int res= 0;
const char *correct_dir_name;
DBUG_ENTER("my_sync_dir");
DBUG_PRINT("my",("Dir: '%s' my_flags: %lu", dir_name, my_flags));
/* 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 __attribute__((unused)),
myf my_flags __attribute__((unused)))
{
#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 & ~MY_NOSYMLINKS);
#else
return 0;
#endif
}
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