1 files changed, 88 insertions, 0 deletions
diff --git a/lib/ext2fs/flushb.c b/lib/ext2fs/flushb.c
new file mode 100644
index 0000000..bb7daf4
--- /dev/null
+++ b/lib/ext2fs/flushb.c
@@ -0,0 +1,88 @@
+/*
+ * 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 Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include "config.h"
+#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 defined(HAVE_FSYNC)
+	if (fsync (fd) == -1)
+		return errno;
+#endif
+
+	if (flushb) {
+		errcode_t	retval = 0;
+
+#ifdef BLKFLSBUF
+		if (ioctl (fd, BLKFLSBUF, 0) == 0)
+			return 0;
+		retval = errno;
+#elif defined(__linux__)
+#warning BLKFLSBUF not defined
+#endif
+#ifdef FDFLUSH
+		/* In case this is a floppy */
+		if (ioctl(fd, FDFLUSH, 0) == 0)
+			return 0;
+		if (retval == 0)
+			retval = errno;
+#elif defined(__linux__)
+#warning FDFLUSH not defined
+#endif
+		return retval;
+	}
+	return 0;
+}