source: branches/stable/mindi-busybox/e2fsprogs/ext2fs/flushb.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 1.9 KB
Line 
1/*
2 * flushb.c --- Hides system-dependent information for both syncing a
3 *  device to disk and to flush any buffers from disk cache.
4 *
5 * Copyright (C) 2000 Theodore Ts'o.
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Public
9 * License.
10 * %End-Header%
11 */
12
13#include <stdio.h>
14#if HAVE_ERRNO_H
15#include <errno.h>
16#endif
17#if HAVE_UNISTD_H
18#include <unistd.h>
19#endif
20#if HAVE_SYS_IOCTL_H
21#include <sys/ioctl.h>
22#endif
23#if HAVE_SYS_MOUNT_H
24#include <sys/param.h>
25#include <sys/mount.h>      /* This may define BLKFLSBUF */
26#endif
27
28#include "ext2_fs.h"
29#include "ext2fs.h"
30
31/*
32 * For Linux, define BLKFLSBUF and FDFLUSH if necessary, since
33 * not all portable header file does so for us.  This really should be
34 * fixed in the glibc header files.  (Recent glibcs appear to define
35 * BLKFLSBUF in sys/mount.h, but FDFLUSH still doesn't seem to be
36 * defined anywhere portable.)  Until then....
37 */
38#ifdef __linux__
39#ifndef BLKFLSBUF
40#define BLKFLSBUF   _IO(0x12,97)    /* flush buffer cache */
41#endif
42#ifndef FDFLUSH
43#define FDFLUSH     _IO(2,0x4b) /* flush floppy disk */
44#endif
45#endif
46
47/*
48 * This function will sync a device/file, and optionally attempt to
49 * flush the buffer cache.  The latter is basically only useful for
50 * system benchmarks and for torturing systems in burn-in tests.  :)
51 */
52errcode_t ext2fs_sync_device(int fd, int flushb)
53{
54    /*
55     * We always sync the device in case we're running on old
56     * kernels for which we can lose data if we don't.  (There
57     * still is a race condition for those kernels, but this
58     * reduces it greatly.)
59     */
60    if (fsync (fd) == -1)
61        return errno;
62
63    if (flushb) {
64
65#ifdef BLKFLSBUF
66        if (ioctl (fd, BLKFLSBUF, 0) == 0)
67            return 0;
68#else
69#ifdef __GNUC__
70# warning BLKFLSBUF not defined
71#endif /* __GNUC__ */
72#endif
73#ifdef FDFLUSH
74        ioctl (fd, FDFLUSH, 0);   /* In case this is a floppy */
75#else
76#ifdef __GNUC__
77# warning FDFLUSH not defined
78#endif /* __GNUC__ */
79#endif
80    }
81    return 0;
82}
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