Subject: bug#7362: dd strangeness

From: Pádraig Brady <[email-masked]>
Date: Sat, 05 Mar 2011 01:44:16 +0000

I'm going to apply the following.

commit decea1c17bcbce3f70bfb50b7de66de5eaba9b91
Author: Pádraig Brady <[email-masked]>
Date:   Fri Feb 25 12:27:25 2011 +0000

    dd: warn when we disable oflag=direct not at EOF

    An alternative to this is to auto enable iflag=fullblock
    when oflag=direct and bs= is specified.
    It was thought better though, to warn about the specific issue,
    and give full control of dd's options to the user.

    * src/dd.c (iwrite): Warn, when we write after having
    disabled O_DIRECT.
    See https://bugzilla.redhat.com/show_bug.cgi?id=614605

diff --git a/src/dd.c b/src/dd.c
index daddc1e..fd468a6 100644
--- a/src/dd.c
+++ b/src/dd.c
@@ -837,6 +837,12 @@ iwrite (int fd, char const *buf, size_t size)
 {
   size_t total_written = 0;

+  if ((output_flags & O_DIRECT) && w_partial == 1)
+    {
+      error (0, 0, _("dd: warning: partial read; oflag=direct disabled; "
+                     "suggest iflag=fullblock"));
+    }
+
   if ((output_flags & O_DIRECT) && size < output_blocksize)
     {
       int old_flags = fcntl (STDOUT_FILENO, F_GETFL);