--- block.c	Tue May 16 13:06:15 2006
+++ block.c	Tue May 16 13:07:51 2006
@@ -753,6 +753,20 @@
     close(s->fd);
 }
 
+int qemu_ftruncate(int fd, off_t length)
+/* ftruncate() isn't guarranteed to grow a file, according to POSIX. **
+** This is. */
+{
+    int res = ftruncate(fd, length);
+    if (res && (errno == EPERM))
+    {
+        if ((lseek( fd, length - 1, SEEK_SET) == (off_t)-1) ||
+       	    (write(fd, "\0", 1) == -1))
+       return -1;
+    }
+    return res;
+}
+
 static int raw_create(const char *filename, int64_t total_size,
                       const char *backing_file, int flags)
 {
@@ -765,7 +779,7 @@
               0644);
     if (fd < 0)
         return -EIO;
-    ftruncate(fd, total_size * 512);
+    qemu_ftruncate(fd, total_size * 512);
     close(fd);
     return 0;
 }