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/* vi: set sw=4 ts=4: */
/*
* flushb.c --- Hides system-dependent information for both syncing a
* device to disk and to flush any buffers from disk cache.
*
* Copyright (C) 2000 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#if HAVE_SYS_MOUNT_H
#include <sys/param.h>
#include <sys/mount.h> /* This may define BLKFLSBUF */
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
/*
* For Linux, define BLKFLSBUF and FDFLUSH if necessary, since
* not all portable header file does so for us. This really should be
* fixed in the glibc header files. (Recent glibcs appear to define
* BLKFLSBUF in sys/mount.h, but FDFLUSH still doesn't seem to be
* defined anywhere portable.) Until then....
*/
#ifdef __linux__
#ifndef BLKFLSBUF
#define BLKFLSBUF _IO(0x12,97) /* flush buffer cache */
#endif
#ifndef FDFLUSH
#define FDFLUSH _IO(2,0x4b) /* flush floppy disk */
#endif
#endif
/*
* This function will sync a device/file, and optionally attempt to
* flush the buffer cache. The latter is basically only useful for
* system benchmarks and for torturing systems in burn-in tests. :)
*/
errcode_t ext2fs_sync_device(int fd, int flushb)
{
/*
* We always sync the device in case we're running on old
* kernels for which we can lose data if we don't. (There
* still is a race condition for those kernels, but this
* reduces it greatly.)
*/
if (fsync (fd) == -1)
return errno;
if (flushb) {
#ifdef BLKFLSBUF
if (ioctl (fd, BLKFLSBUF, 0) == 0)
return 0;
#else
#ifdef __GNUC__
# warning BLKFLSBUF not defined
#endif /* __GNUC__ */
#endif
#ifdef FDFLUSH
ioctl (fd, FDFLUSH, 0); /* In case this is a floppy */
#else
#ifdef __GNUC__
# warning FDFLUSH not defined
#endif /* __GNUC__ */
#endif
}
return 0;
}
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