diff --git a/ChangeLog b/ChangeLog
index 9e51dbc221..c89c926e98 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Dec 13 21:26:33 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* io.c (simple_sendfile): disable the use of sendfile(2) on
+	  FreeBSD. It blocks on TestIO#test_copy_stream_socket.
+
 Mon Dec 13 18:35:33 2010  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* io.c: define USE_SENDFILE on FreeBSD or DragonFly BSD.
diff --git a/io.c b/io.c
index 30767af695..73579dd685 100644
--- a/io.c
+++ b/io.c
@@ -8216,7 +8216,8 @@ simple_sendfile(int out_fd, int in_fd, off_t *offset, off_t count)
     return sendfile(out_fd, in_fd, offset, (size_t)count);
 }
 
-# elif defined(__FreeBSD__) || defined(__DragonFly__)
+# elif 0 /* defined(__FreeBSD__) || defined(__DragonFly__) */
+/* at least FreeBSD 8.1 + r30193, sendfiles blocks its execution... */
 #  define USE_SENDFILE
 
 #  ifdef HAVE_SYS_UIO_H
@@ -8227,14 +8228,16 @@ static ssize_t
 simple_sendfile(int out_fd, int in_fd, off_t *offset, off_t count)
 {
     int r;
-    size_t sbytes;
+    off_t sbytes;
+    struct sf_hdtr hdtr = {NULL, 0, NULL, 0};
 #  if SIZEOF_OFF_T > SIZEOF_SIZE_T
     /* we are limited by the 32-bit ssize_t return value on 32-bit */
     if (count > (off_t)SSIZE_MAX)
         count = SSIZE_MAX;
 #  endif
-    r = sendfile(in_fd, out_fd, *offset, (size_t)count, NULL, &sbytes, 0);
+    r = sendfile(in_fd, out_fd, offset ? *offset : 0, (size_t)count, &hdtr, &sbytes, SF_NODISKIO);
     if (r != 0) return -1;
+    if (offset) *offset = sbytes;
     return (ssize_t)sbytes;
 }