Index: user/marcel/libvdsk/libvdsk/vdsk.c
===================================================================
--- user/marcel/libvdsk/libvdsk/vdsk.c	(revision 274810)
+++ user/marcel/libvdsk/libvdsk/vdsk.c	(revision 274811)
@@ -1,163 +1,166 @@
 /*-
  * Copyright (c) 2014 Marcel Moolenaar
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/disk.h>
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <vdsk.h>
 
 #include "vdsk_int.h"
 
 static struct vdsk *
 vdsk_deref(vdskctx ctx)
 {
 	struct vdsk *vdsk = ctx;
 
 	return (vdsk - 1);
 }
 
 vdskctx
 vdsk_open(const char *path, int flags, size_t size)
 {
 	struct stat sb;
 	vdskctx ctx;
 	struct vdsk *vdsk;
 
 	ctx = NULL;
 
 	do {
 		size += sizeof(struct vdsk);
 		vdsk = calloc(1, size);
 		if (vdsk == NULL)
 			break;
 
 		vdsk->fd = open(path, flags);
 		if (vdsk->fd == -1)
 			break;
 
 		if (fstat(vdsk->fd, &sb) == -1)
 			break;
 
 		if (S_ISCHR(sb.st_mode)) {
 			if (ioctl(vdsk->fd, DIOCGMEDIASIZE,
 			    &vdsk->capacity) < 0)
 				break;
 			if (ioctl(vdsk->fd, DIOCGSECTORSIZE,
 			    &vdsk->sectorsize) < 0)
 				break;
 		} else {
 			vdsk->capacity = sb.st_size;
 			vdsk->sectorsize = DEV_BSIZE;
 		}
 
 		/* Complete... */
 		ctx = vdsk + 1;
 	} while (0);
 
 	if (ctx == NULL) {
 		if (vdsk != NULL) {
 			if (vdsk->fd != -1)
 				close(vdsk->fd);
 			free(vdsk);
 			vdsk = NULL;
 		}
 	}
 
 	return (ctx);
 }
 
 int
 vdsk_close(vdskctx ctx)
 {
 	struct vdsk *vdsk = vdsk_deref(ctx);
 
 	close(vdsk->fd);
 	free(vdsk);
 	return (0);
 }
 
 off_t
 vdsk_capacity(vdskctx ctx)
 {
 	struct vdsk *vdsk = vdsk_deref(ctx);
 
 	return (vdsk->capacity);
 }
 
 int
 vdsk_sectorsize(vdskctx ctx)
 {
 	struct vdsk *vdsk = vdsk_deref(ctx);
 
 	return (vdsk->sectorsize);
 }
 
 ssize_t
 vdsk_read(vdskctx ctx, void *buf, size_t nbytes, off_t offset)
 {
 	struct vdsk *vdsk = vdsk_deref(ctx);
 	ssize_t res;
 
 	res = pread(vdsk->fd, buf, nbytes, offset);
 	return (res);
 }
 
 ssize_t
 vdsk_readv(vdskctx ctx, const struct iovec *iov, int iovcnt, off_t offset)
 {
 	struct vdsk *vdsk = vdsk_deref(ctx);
 	ssize_t res;
 
 	res = preadv(vdsk->fd, iov, iovcnt, offset);
 	return (res);
 }
 
 ssize_t
 vdsk_writev(vdskctx ctx, const struct iovec *iov, int iovcnt, off_t offset)
 {
 	struct vdsk *vdsk = vdsk_deref(ctx);
 	ssize_t res;
 
 	res = pwritev(vdsk->fd, iov, iovcnt, offset);
 	return (res);
 }
 
 int
-vdsk_flush(vdskctx ctx __unused)
+vdsk_flush(vdskctx ctx)
 {
+	struct vdsk *vdsk = vdsk_deref(ctx);
+	int res;
 
-	return (0);
+	res = fsync(vdsk->fd);
+	return ((res == -1) ? errno : 0);
 }