2 * flushb.c --- Hides system-dependent information for both syncing a
3 * device to disk and to flush any buffers from disk cache.
5 * Copyright (C) 2000 Theodore Ts'o.
8 * This file may be redistributed under the terms of the GNU Library
9 * General Public License, version 2.
22 #include <sys/ioctl.h>
25 #include <sys/param.h>
26 #include <sys/mount.h> /* This may define BLKFLSBUF */
33 * For Linux, define BLKFLSBUF and FDFLUSH if necessary, since
34 * not all portable header file does so for us. This really should be
35 * fixed in the glibc header files. (Recent glibcs appear to define
36 * BLKFLSBUF in sys/mount.h, but FDFLUSH still doesn't seem to be
37 * defined anywhere portable.) Until then....
41 #define BLKFLSBUF _IO(0x12,97) /* flush buffer cache */
44 #define FDFLUSH _IO(2,0x4b) /* flush floppy disk */
49 * This function will sync a device/file, and optionally attempt to
50 * flush the buffer cache. The latter is basically only useful for
51 * system benchmarks and for torturing systems in burn-in tests. :)
53 errcode_t ext2fs_sync_device(int fd, int flushb)
56 * We always sync the device in case we're running on old
57 * kernels for which we can lose data if we don't. (There
58 * still is a race condition for those kernels, but this
59 * reduces it greatly.)
61 #if defined(HAVE_FSYNC)
69 if (ioctl (fd, BLKFLSBUF, 0) == 0)
71 #elif defined(__linux__)
72 #warning BLKFLSBUF not defined
75 return ioctl(fd, FDFLUSH, 0); /* In case this is a floppy */
76 #elif defined(__linux__)
77 #warning FDFLUSH not defined