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