1 files changed, 82 insertions, 0 deletions

diff --git a/e2fsprogs/ext2fs/flushb.c b/e2fsprogs/ext2fs/flushb.c
new file mode 100644
index 000000000..18827955f
--- /dev/null
+++ b/e2fsprogs/ext2fs/flushb.c
@@ -0,0 +1,82 @@
+/*
+ * 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;
+}