Prereq: "2.5.6"
diff -cr --new-file /var/tmp/postfix-2.5.6/src/global/mail_version.h ./src/global/mail_version.h
*** /var/tmp/postfix-2.5.6/src/global/mail_version.h	Sat Jan  3 20:27:10 2009
--- ./src/global/mail_version.h	Tue May 12 11:15:18 2009
***************
*** 20,27 ****
    * Patches change both the patchlevel and the release date. Snapshots have no
    * patchlevel; they change the release date only.
    */
! #define MAIL_RELEASE_DATE	"20090103"
! #define MAIL_VERSION_NUMBER	"2.5.6"
  
  #ifdef SNAPSHOT
  # define MAIL_VERSION_DATE	"-" MAIL_RELEASE_DATE
--- 20,27 ----
    * Patches change both the patchlevel and the release date. Snapshots have no
    * patchlevel; they change the release date only.
    */
! #define MAIL_RELEASE_DATE	"20090512"
! #define MAIL_VERSION_NUMBER	"2.5.7"
  
  #ifdef SNAPSHOT
  # define MAIL_VERSION_DATE	"-" MAIL_RELEASE_DATE
diff -cr --new-file /var/tmp/postfix-2.5.6/HISTORY ./HISTORY
*** /var/tmp/postfix-2.5.6/HISTORY	Sat Jan  3 20:25:35 2009
--- ./HISTORY	Tue May 12 10:28:07 2009
***************
*** 14469,14471 ****
--- 14469,14516 ----
  
  	Documentation: log the "*" pattern as the last transport
  	map lookup. File: proto/transport.
+ 
+ 20090122
+ 
+ 	Bugfix: the data_directory was not automatically created!
+ 	File: conf/postfix-files.
+ 
+ 20090304
+ 
+ 	Cleanup: skip over suspended or throttled queues while
+ 	looking for delivery requests. File: *qmgr/qmgr_transport.c.
+ 
+ 20090305
+ 
+ 	Bugfix: in the "new queue manager", the _destination_rate_delay
+ 	code needed to postpone the job scheduler updates after
+ 	delivery completion, otherwise the scheduler could loop on
+ 	blocked jobs.  Victor & Wietse.  File: qmgr/qmgr_entry.c,
+ 	qmgr/qmgr_queue.c, qmgr/qmgr_job.c.
+ 
+ 	Cleanup: report a "queue file write error", instead of
+ 	passing though bogus 2xx replies from proxy filters to SMTP
+ 	clients.  File: smtpd/smtpd_proxy.c.
+ 
+ 20090310
+ 
+ 	Bugfix: Postfix used mumble_concurrency_failed_cohort_limit
+ 	instead of mumble_destination_concurrency_failed_cohort_limit
+ 	as documented. File: global/mail_params.h.
+ 
+ 20090419
+ 
+ 	Bugfix: don't re-enable SIGHUP if it is ignored in the
+ 	parent. This may cause random "Postfix integrity check
+ 	failed" errors at boot time (POSIX SIGHUP death), causing
+ 	Postfix not to start. We duplicate code from postdrop and
+ 	thus avoid past mistakes.  File: postsuper/postsuper.c.
+ 
+ 	Robustness: don't re-enable SIGTERM if it is ignored in the
+ 	parent. Files: postsuper/postsuper.c, postdrop/postdrop.c.
+ 
+ 20090428
+ 
+ 	Bugfix: don't disable MIME parsing with smtp_header_checks,
+ 	smtp_mime_header_checks, smtp_nested_header_checks or with
+ 	smtp_body_checks. Bug reported by Victor. File: smtp/smtp_proto.c.
diff -cr --new-file /var/tmp/postfix-2.5.6/conf/postfix-files ./conf/postfix-files
*** /var/tmp/postfix-2.5.6/conf/postfix-files	Wed Jan 23 19:13:49 2008
--- ./conf/postfix-files	Thu Jan 22 19:47:26 2009
***************
*** 42,48 ****
  # permissions, so that running "make install" fixes any glitches.
  #
  $config_directory:d:root:-:755:u
! $data_directory:d:$mail_owner:-:700:u
  $daemon_directory:d:root:-:755:u
  $queue_directory:d:root:-:755:uc
  $sample_directory:d:root:-:755:o
--- 42,48 ----
  # permissions, so that running "make install" fixes any glitches.
  #
  $config_directory:d:root:-:755:u
! $data_directory:d:$mail_owner:-:700:uc
  $daemon_directory:d:root:-:755:u
  $queue_directory:d:root:-:755:uc
  $sample_directory:d:root:-:755:o
diff -cr --new-file /var/tmp/postfix-2.5.6/html/postconf.5.html ./html/postconf.5.html
*** /var/tmp/postfix-2.5.6/html/postconf.5.html	Sun Jul 27 15:47:10 2008
--- ./html/postconf.5.html	Tue May 12 09:50:58 2009
***************
*** 1792,1798 ****
  <p> A pseudo-cohort is the number of deliveries equal to a destination's
  delivery concurrency. </p>
  
! <p> Use <a href="postconf.5.html#transport_destination_concurrency_positive_feedback"><i>transport</i>_destination_concurrency_negative_feedback</a>
  to specify a transport-specific override, where <i>transport</i>
  is the <a href="master.5.html">master.cf</a>
  name of the message delivery transport. </p>
--- 1792,1798 ----
  <p> A pseudo-cohort is the number of deliveries equal to a destination's
  delivery concurrency. </p>
  
! <p> Use <a href="postconf.5.html#transport_destination_concurrency_negative_feedback"><i>transport</i>_destination_concurrency_negative_feedback</a>
  to specify a transport-specific override, where <i>transport</i>
  is the <a href="master.5.html">master.cf</a>
  name of the message delivery transport. </p>
***************
*** 3718,3724 ****
  <blockquote>
  <pre>
  /etc/postfix/<a href="master.5.html">master.cf</a>:
!     mylmtp ... lmtp -o <a href="postconf.5.html#lmtp_lhloname">lmtp_lhlo_name</a>=foo.bar.com
  </pre>
  </blockquote>
  
--- 3718,3724 ----
  <blockquote>
  <pre>
  /etc/postfix/<a href="master.5.html">master.cf</a>:
!     mylmtp ... lmtp -o <a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a>=foo.bar.com
  </pre>
  </blockquote>
  
diff -cr --new-file /var/tmp/postfix-2.5.6/mantools/postlink ./mantools/postlink
*** /var/tmp/postfix-2.5.6/mantools/postlink	Sun Jul 27 15:34:16 2008
--- ./mantools/postlink	Tue May 12 09:47:29 2009
***************
*** 254,260 ****
      s;\blmtp_tls_note_starttls_offer\b;<a href="postconf.5.html#lmtp_tls_note_starttls_offer">$&</a>;g;
      s;\blmtp_sender_dependent_authentication\b;<a href="postconf.5.html#lmtp_sender_dependent_authentication">$&</a>;g;
      s;\blmtp_sasl_path\b;<a href="postconf.5.html#lmtp_sasl_path">$&</a>;g;
!     s;\blmtp_lhlo_name\b;<a href="postconf.5.html#lmtp_lhloname">$&</a>;g;
      s;\blmtp_connect_timeout\b;<a href="postconf.5.html#lmtp_connect_timeout">$&</a>;g;
      s;\blmtp_data_done_timeout\b;<a href="postconf.5.html#lmtp_data_done_timeout">$&</a>;g;
      s;\blmtp_data_init_timeout\b;<a href="postconf.5.html#lmtp_data_init_timeout">$&</a>;g;
--- 254,260 ----
      s;\blmtp_tls_note_starttls_offer\b;<a href="postconf.5.html#lmtp_tls_note_starttls_offer">$&</a>;g;
      s;\blmtp_sender_dependent_authentication\b;<a href="postconf.5.html#lmtp_sender_dependent_authentication">$&</a>;g;
      s;\blmtp_sasl_path\b;<a href="postconf.5.html#lmtp_sasl_path">$&</a>;g;
!     s;\blmtp_lhlo_name\b;<a href="postconf.5.html#lmtp_lhlo_name">$&</a>;g;
      s;\blmtp_connect_timeout\b;<a href="postconf.5.html#lmtp_connect_timeout">$&</a>;g;
      s;\blmtp_data_done_timeout\b;<a href="postconf.5.html#lmtp_data_done_timeout">$&</a>;g;
      s;\blmtp_data_init_timeout\b;<a href="postconf.5.html#lmtp_data_init_timeout">$&</a>;g;
***************
*** 636,642 ****
      # Transport-dependent magical parameters.
  
      s;(<i>transport</i>)(<b>)?(_destination_concurrency_failed_cohort_limit)\b;$2<a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit">$1$3</a>;g;
!     s;(<i>transport</i>)(<b>)?(_destination_concurrency_negative_feedback)\b;$2<a href="postconf.5.html#transport_destination_concurrency_positive_feedback">$1$3</a>;g;
      s;(<i>transport</i>)(<b>)?(_destination_concurrency_positive_feedback)\b;$2<a href="postconf.5.html#transport_destination_concurrency_positive_feedback">$1$3</a>;g;
      s;(<i>transport</i>)(<b>)?(_delivery_slot_cost)\b;$2<a href="postconf.5.html#transport_delivery_slot_cost">$1$3</a>;g;
      s;(<i>transport</i>)(<b>)?(_delivery_slot_discount)\b;$2<a href="postconf.5.html#transport_delivery_slot_discount">$1$3</a>;g;
--- 636,642 ----
      # Transport-dependent magical parameters.
  
      s;(<i>transport</i>)(<b>)?(_destination_concurrency_failed_cohort_limit)\b;$2<a href="postconf.5.html#transport_destination_concurrency_failed_cohort_limit">$1$3</a>;g;
!     s;(<i>transport</i>)(<b>)?(_destination_concurrency_negative_feedback)\b;$2<a href="postconf.5.html#transport_destination_concurrency_negative_feedback">$1$3</a>;g;
      s;(<i>transport</i>)(<b>)?(_destination_concurrency_positive_feedback)\b;$2<a href="postconf.5.html#transport_destination_concurrency_positive_feedback">$1$3</a>;g;
      s;(<i>transport</i>)(<b>)?(_delivery_slot_cost)\b;$2<a href="postconf.5.html#transport_delivery_slot_cost">$1$3</a>;g;
      s;(<i>transport</i>)(<b>)?(_delivery_slot_discount)\b;$2<a href="postconf.5.html#transport_delivery_slot_discount">$1$3</a>;g;
diff -cr --new-file /var/tmp/postfix-2.5.6/src/global/mail_params.h ./src/global/mail_params.h
*** /var/tmp/postfix-2.5.6/src/global/mail_params.h	Sun Jul 27 15:10:27 2008
--- ./src/global/mail_params.h	Tue May 12 09:55:08 2009
***************
*** 2899,2910 ****
    * Scheduler concurrency feedback algorithms.
    */
  #define VAR_CONC_POS_FDBACK	"default_destination_concurrency_positive_feedback"
! #define _CONC_POS_FDBACK	"_concurrency_positive_feedback"
  #define DEF_CONC_POS_FDBACK	"1"
  extern char *var_conc_pos_feedback;
  
  #define VAR_CONC_NEG_FDBACK	"default_destination_concurrency_negative_feedback"
! #define _CONC_NEG_FDBACK	"_concurrency_negative_feedback"
  #define DEF_CONC_NEG_FDBACK	"1"
  extern char *var_conc_neg_feedback;
  
--- 2899,2910 ----
    * Scheduler concurrency feedback algorithms.
    */
  #define VAR_CONC_POS_FDBACK	"default_destination_concurrency_positive_feedback"
! #define _CONC_POS_FDBACK	"_destination_concurrency_positive_feedback"
  #define DEF_CONC_POS_FDBACK	"1"
  extern char *var_conc_pos_feedback;
  
  #define VAR_CONC_NEG_FDBACK	"default_destination_concurrency_negative_feedback"
! #define _CONC_NEG_FDBACK	"_destination_concurrency_negative_feedback"
  #define DEF_CONC_NEG_FDBACK	"1"
  extern char *var_conc_neg_feedback;
  
***************
*** 2912,2918 ****
  #define CONC_FDBACK_NAME_SQRT_WIN "sqrt_concurrency"
  
  #define VAR_CONC_COHORT_LIM	"default_destination_concurrency_failed_cohort_limit"
! #define _CONC_COHORT_LIM	"_concurrency_failed_cohort_limit"
  #define DEF_CONC_COHORT_LIM	1
  extern int var_conc_cohort_limit;
  
--- 2912,2918 ----
  #define CONC_FDBACK_NAME_SQRT_WIN "sqrt_concurrency"
  
  #define VAR_CONC_COHORT_LIM	"default_destination_concurrency_failed_cohort_limit"
! #define _CONC_COHORT_LIM	"_destination_concurrency_failed_cohort_limit"
  #define DEF_CONC_COHORT_LIM	1
  extern int var_conc_cohort_limit;
  
diff -cr --new-file /var/tmp/postfix-2.5.6/src/oqmgr/qmgr_transport.c ./src/oqmgr/qmgr_transport.c
*** /var/tmp/postfix-2.5.6/src/oqmgr/qmgr_transport.c	Sun Dec  2 13:13:26 2007
--- ./src/oqmgr/qmgr_transport.c	Thu Mar  5 16:06:43 2009
***************
*** 286,291 ****
--- 286,293 ----
  	    continue;
  	need = xport->pending + 1;
  	for (queue = xport->queue_list.next; queue; queue = queue->peers.next) {
+ 	    if (QMGR_QUEUE_READY(queue) == 0)
+ 		continue;
  	    if ((need -= MIN5af51743e4eef(queue->window - queue->busy_refcount,
  					  queue->todo_refcount)) <= 0) {
  		QMGR_LIST_ROTATE(qmgr_transport_list, xport);
diff -cr --new-file /var/tmp/postfix-2.5.6/src/postdrop/postdrop.c ./src/postdrop/postdrop.c
*** /var/tmp/postfix-2.5.6/src/postdrop/postdrop.c	Tue Jan  8 15:35:08 2008
--- ./src/postdrop/postdrop.c	Tue May 12 09:40:28 2009
***************
*** 340,346 ****
  
      signal(SIGINT, postdrop_sig);
      signal(SIGQUIT, postdrop_sig);
!     signal(SIGTERM, postdrop_sig);
      if (signal(SIGHUP, SIG_IGN) == SIG_DFL)
  	signal(SIGHUP, postdrop_sig);
      msg_cleanup(postdrop_cleanup);
--- 340,347 ----
  
      signal(SIGINT, postdrop_sig);
      signal(SIGQUIT, postdrop_sig);
!     if (signal(SIGTERM, SIG_IGN) == SIG_DFL)
! 	signal(SIGTERM, postdrop_sig);
      if (signal(SIGHUP, SIG_IGN) == SIG_DFL)
  	signal(SIGHUP, postdrop_sig);
      msg_cleanup(postdrop_cleanup);
diff -cr --new-file /var/tmp/postfix-2.5.6/src/postsuper/postsuper.c ./src/postsuper/postsuper.c
*** /var/tmp/postfix-2.5.6/src/postsuper/postsuper.c	Wed May  2 14:39:27 2007
--- ./src/postsuper/postsuper.c	Tue May 12 09:43:20 2009
***************
*** 974,984 ****
      /*
       * This commands requires root privileges. We therefore do not worry
       * about hostile signals, and report problems via msg_warn().
       */
!     if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
! 	(void) signal(SIGINT, SIG_IGN);
  	(void) signal(SIGQUIT, SIG_IGN);
  	(void) signal(SIGTERM, SIG_IGN);
  	if (inode_mismatch > 0 || inode_fixed > 0 || position_mismatch > 0)
  	    msg_warn("OPERATION INCOMPLETE -- RERUN COMMAND TO FIX THE QUEUE FIRST");
  	if (sig)
--- 974,990 ----
      /*
       * This commands requires root privileges. We therefore do not worry
       * about hostile signals, and report problems via msg_warn().
+      * 
+      * We use the in-kernel SIGINT handler address as an atomic variable to
+      * prevent nested interrupted() calls. For this reason, main() must
+      * configure interrupted() as SIGINT handler before other signal handlers
+      * are allowed to invoke interrupted(). See also similar code in
+      * postdrop.
       */
!     if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
  	(void) signal(SIGQUIT, SIG_IGN);
  	(void) signal(SIGTERM, SIG_IGN);
+ 	(void) signal(SIGHUP, SIG_IGN);
  	if (inode_mismatch > 0 || inode_fixed > 0 || position_mismatch > 0)
  	    msg_warn("OPERATION INCOMPLETE -- RERUN COMMAND TO FIX THE QUEUE FIRST");
  	if (sig)
***************
*** 1175,1185 ****
       * 
       * Set up signal handlers after permanently dropping super-user privileges,
       * so that signal handlers will always run with the correct privileges.
       */
-     signal(SIGHUP, interrupted);
      signal(SIGINT, interrupted);
      signal(SIGQUIT, interrupted);
!     signal(SIGTERM, interrupted);
      msg_cleanup(fatal_warning);
  
      /*
--- 1181,1200 ----
       * 
       * Set up signal handlers after permanently dropping super-user privileges,
       * so that signal handlers will always run with the correct privileges.
+      * 
+      * XXX Don't enable SIGHUP or SIGTERM if it was ignored by the parent.
+      * 
+      * interrupted() uses the in-kernel SIGINT handler address as an atomic
+      * variable to prevent nested interrupted() calls. For this reason, the
+      * SIGINT handler must be configured before other signal handlers are
+      * allowed to invoke interrupted(). See also similar code in postdrop.
       */
      signal(SIGINT, interrupted);
      signal(SIGQUIT, interrupted);
!     if (signal(SIGTERM, SIG_IGN) == SIG_DFL)
! 	signal(SIGTERM, interrupted);
!     if (signal(SIGHUP, SIG_IGN) == SIG_DFL)
! 	signal(SIGHUP, interrupted);
      msg_cleanup(fatal_warning);
  
      /*
diff -cr --new-file /var/tmp/postfix-2.5.6/src/qmgr/qmgr.h ./src/qmgr/qmgr.h
*** /var/tmp/postfix-2.5.6/src/qmgr/qmgr.h	Sat Dec  8 11:01:59 2007
--- ./src/qmgr/qmgr.h	Thu Mar  5 16:36:32 2009
***************
*** 436,441 ****
--- 436,442 ----
  
  extern QMGR_ENTRY *qmgr_job_entry_select(QMGR_TRANSPORT *);
  extern QMGR_PEER *qmgr_peer_select(QMGR_JOB *);
+ extern void qmgr_job_blocker_update(QMGR_QUEUE *);
  
  extern QMGR_JOB *qmgr_job_obtain(QMGR_MESSAGE *, QMGR_TRANSPORT *);
  extern void qmgr_job_free(QMGR_JOB *);
diff -cr --new-file /var/tmp/postfix-2.5.6/src/qmgr/qmgr_entry.c ./src/qmgr/qmgr_entry.c
*** /var/tmp/postfix-2.5.6/src/qmgr/qmgr_entry.c	Fri Dec 14 17:47:21 2007
--- ./src/qmgr/qmgr_entry.c	Thu Mar  5 16:29:46 2009
***************
*** 299,327 ****
      }
  
      /*
!      * If the queue was blocking some of the jobs on the job list, check if
!      * the concurrency limit has lifted. If there are still some pending
!      * deliveries, give it a try and unmark all transport blockers at once.
!      * The qmgr_job_entry_select() will do the rest. In either case make sure
!      * the queue is not marked as a blocker anymore, with extra handling of
!      * queues which were declared dead.
       * 
!      * Note that changing the blocker status also affects the candidate cache.
!      * Most of the cases would be automatically recognized by the current job
!      * change, but we play safe and reset the cache explicitly below.
!      * 
!      * Keeping the transport blocker tag odd is an easy way to make sure the tag
!      * never matches jobs that are not explicitly marked as blockers.
       */
!     if (queue->blocker_tag == transport->blocker_tag) {
! 	if (queue->window > queue->busy_refcount && queue->todo.next != 0) {
! 	    transport->blocker_tag += 2;
! 	    transport->job_current = transport->job_list.next;
! 	    transport->candidate_cache_current = 0;
! 	}
! 	if (queue->window > queue->busy_refcount || QMGR_QUEUE_THROTTLED(queue))
! 	    queue->blocker_tag = 0;
      }
  
      /*
       * When there are no more entries for this peer, discard the peer
--- 299,323 ----
      }
  
      /*
!      * We implement a rate-limited queue by emulating a slow delivery
!      * channel. We insert the artificial delays with qmgr_queue_suspend().
       * 
!      * When a queue is suspended, we must postpone any job scheduling decisions
!      * until the queue is resumed. Otherwise, we make those decisions now.
!      * The job scheduling decisions are made by qmgr_job_blocker_update().
       */
!     if (which == QMGR_QUEUE_BUSY && transport->rate_delay > 0) {
! 	if (queue->window > 1)
! 	    msg_panic("%s: queue %s/%s: window %d > 1 on rate-limited service",
! 		      myname, transport->name, queue->name, queue->window);
! 	if (QMGR_QUEUE_THROTTLED(queue))	/* XXX */
! 	    qmgr_queue_unthrottle(queue);
! 	if (QMGR_QUEUE_READY(queue))
! 	    qmgr_queue_suspend(queue, transport->rate_delay);
      }
+     if (!QMGR_QUEUE_SUSPENDED(queue)
+ 	&& queue->blocker_tag == transport->blocker_tag)
+ 	qmgr_job_blocker_update(queue);
  
      /*
       * When there are no more entries for this peer, discard the peer
***************
*** 336,354 ****
       */
      if (which == QMGR_QUEUE_BUSY)
  	queue->last_done = event_time();
- 
-     /*
-      * Suspend a rate-limited queue, so that mail trickles out.
-      */
-     if (which == QMGR_QUEUE_BUSY && transport->rate_delay > 0) {
- 	if (queue->window > 1)
- 	    msg_panic("%s: queue %s/%s: window %d > 1 on rate-limited service",
- 		      myname, transport->name, queue->name, queue->window);
- 	if (QMGR_QUEUE_THROTTLED(queue))	/* XXX */
- 	    qmgr_queue_unthrottle(queue);
- 	if (QMGR_QUEUE_READY(queue))
- 	    qmgr_queue_suspend(queue, transport->rate_delay);
-     }
  
      /*
       * When the in-core queue for this site is empty and when this site is
--- 332,337 ----
diff -cr --new-file /var/tmp/postfix-2.5.6/src/qmgr/qmgr_job.c ./src/qmgr/qmgr_job.c
*** /var/tmp/postfix-2.5.6/src/qmgr/qmgr_job.c	Tue Nov  7 11:34:07 2006
--- ./src/qmgr/qmgr_job.c	Thu Mar  5 16:43:36 2009
***************
*** 18,23 ****
--- 18,26 ----
  /*
  /*	QMGR_ENTRY *qmgr_job_entry_select(transport)
  /*	QMGR_TRANSPORT *transport;
+ /*
+ /*	void	qmgr_job_blocker_update(queue)
+ /*	QMGR_QUEUE *queue;
  /* DESCRIPTION
  /*	These routines add/delete/manipulate per-transport jobs.
  /*	Each job corresponds to a specific transport and message.
***************
*** 38,43 ****
--- 41,51 ----
  /*	If necessary, an attempt to read more recipients into core is made.
  /*	This can result in creation of more job, queue and entry structures.
  /*
+ /*	qmgr_job_blocker_update() updates the status of blocked
+ /*	jobs after a decrease in the queue's concurrency level,
+ /*	after the queue is throttled, or after the queue is resumed
+ /*	from suspension.
+ /*
  /*	qmgr_job_move_limits() takes care of proper distribution of the
  /*	per-transport recipients limit among the per-transport jobs.
  /*	Should be called whenever a job's recipient slot becomes available.
***************
*** 937,939 ****
--- 945,980 ----
      transport->job_current = 0;
      return (0);
  }
+ 
+ /* qmgr_job_blocker_update - update "blocked job" status */
+ 
+ void     qmgr_job_blocker_update(QMGR_QUEUE *queue)
+ {
+     QMGR_TRANSPORT *transport = queue->transport;
+ 
+     /*
+      * If the queue was blocking some of the jobs on the job list, check if
+      * the concurrency limit has lifted. If there are still some pending
+      * deliveries, give it a try and unmark all transport blockers at once.
+      * The qmgr_job_entry_select() will do the rest. In either case make sure
+      * the queue is not marked as a blocker anymore, with extra handling of
+      * queues which were declared dead.
+      * 
+      * Note that changing the blocker status also affects the candidate cache.
+      * Most of the cases would be automatically recognized by the current job
+      * change, but we play safe and reset the cache explicitly below.
+      * 
+      * Keeping the transport blocker tag odd is an easy way to make sure the tag
+      * never matches jobs that are not explicitly marked as blockers.
+      */
+     if (queue->blocker_tag == transport->blocker_tag) {
+ 	if (queue->window > queue->busy_refcount && queue->todo.next != 0) {
+ 	    transport->blocker_tag += 2;
+ 	    transport->job_current = transport->job_list.next;
+ 	    transport->candidate_cache_current = 0;
+ 	}
+ 	if (queue->window > queue->busy_refcount || QMGR_QUEUE_THROTTLED(queue))
+ 	    queue->blocker_tag = 0;
+     }
+ }
+ 
diff -cr --new-file /var/tmp/postfix-2.5.6/src/qmgr/qmgr_queue.c ./src/qmgr/qmgr_queue.c
*** /var/tmp/postfix-2.5.6/src/qmgr/qmgr_queue.c	Sat Dec  8 09:59:34 2007
--- ./src/qmgr/qmgr_queue.c	Thu Mar  5 17:35:24 2009
***************
*** 66,72 ****
  /*	"slow open" mode, and eliminates the "thundering herd" problem.
  /*
  /*	qmgr_queue_suspend() suspends delivery for this destination
! /*	briefly.
  /* DIAGNOSTICS
  /*	Panic: consistency check failure.
  /* LICENSE
--- 66,76 ----
  /*	"slow open" mode, and eliminates the "thundering herd" problem.
  /*
  /*	qmgr_queue_suspend() suspends delivery for this destination
! /*	briefly. This function invalidates any scheduling decisions
! /*	that are based on the present queue's concurrency window.
! /*	To compensate for work skipped by qmgr_entry_done(), the
! /*	status of blocker jobs is re-evaluated after the queue is
! /*	resumed.
  /* DIAGNOSTICS
  /*	Panic: consistency check failure.
  /* LICENSE
***************
*** 152,160 ****
--- 156,175 ----
      /*
       * Every event handler that leaves a queue in the "ready" state should
       * remove the queue when it is empty.
+      * 
+      * XXX Do not omit the redundant test below. It is here to simplify code
+      * consistency checks. The check is trivially eliminated by the compiler
+      * optimizer. There is no need to sacrifice code clarity for the sake of
+      * performance.
+      * 
+      * XXX Do not expose the blocker job logic here. Rate-limited queues are not
+      * a performance-critical feature. Here, too, there is no need to sacrifice
+      * code clarity for the sake of performance.
       */
      if (QMGR_QUEUE_READY(queue) && queue->todo.next == 0 && queue->busy.next == 0)
  	qmgr_queue_done(queue);
+     else
+ 	qmgr_job_blocker_update(queue);
  }
  
  /* qmgr_queue_suspend - briefly suspend a destination */
diff -cr --new-file /var/tmp/postfix-2.5.6/src/qmgr/qmgr_transport.c ./src/qmgr/qmgr_transport.c
*** /var/tmp/postfix-2.5.6/src/qmgr/qmgr_transport.c	Sun Dec  2 12:53:17 2007
--- ./src/qmgr/qmgr_transport.c	Thu Mar  5 15:08:44 2009
***************
*** 291,296 ****
--- 291,298 ----
  	    continue;
  	need = xport->pending + 1;
  	for (queue = xport->queue_list.next; queue; queue = queue->peers.next) {
+ 	    if (QMGR_QUEUE_READY(queue) == 0)
+ 		continue;
  	    if ((need -= MIN5af51743e4eef(queue->window - queue->busy_refcount,
  					  queue->todo_refcount)) <= 0) {
  		QMGR_LIST_ROTATE(qmgr_transport_list, xport, peers);
diff -cr --new-file /var/tmp/postfix-2.5.6/src/smtp/smtp_proto.c ./src/smtp/smtp_proto.c
*** /var/tmp/postfix-2.5.6/src/smtp/smtp_proto.c	Wed Jan  9 09:04:37 2008
--- ./src/smtp/smtp_proto.c	Tue Apr 28 16:00:34 2009
***************
*** 1771,1782 ****
  		 * XXX Don't downgrade just because generic_maps is turned
  		 * on.
  		 */
! 		if (downgrading || smtp_generic_maps || smtp_header_checks
! 		    || smtp_body_checks)
  		    session->mime_state = mime_state_alloc(downgrading ?
  							   MIME_OPT_DOWNGRADE
  						 | MIME_OPT_REPORT_NESTING :
! 						      MIME_OPT_DISABLE_MIME,
  							   smtp_generic_maps
  						     || smtp_header_checks ?
  						       smtp_header_rewrite :
--- 1771,1785 ----
  		 * XXX Don't downgrade just because generic_maps is turned
  		 * on.
  		 */
! #define SMTP_ANY_CHECKS (smtp_header_checks || smtp_body_checks)
! 
! 		if (downgrading || smtp_generic_maps || SMTP_ANY_CHECKS)
  		    session->mime_state = mime_state_alloc(downgrading ?
  							   MIME_OPT_DOWNGRADE
  						 | MIME_OPT_REPORT_NESTING :
! 						      SMTP_ANY_CHECKS == 0 ?
! 						     MIME_OPT_DISABLE_MIME :
! 							   0,
  							   smtp_generic_maps
  						     || smtp_header_checks ?
  						       smtp_header_rewrite :
diff -cr --new-file /var/tmp/postfix-2.5.6/src/smtpd/smtpd_proxy.c ./src/smtpd/smtpd_proxy.c
*** /var/tmp/postfix-2.5.6/src/smtpd/smtpd_proxy.c	Tue Jan  8 16:12:41 2008
--- ./src/smtpd/smtpd_proxy.c	Fri Mar  6 15:42:40 2009
***************
*** 564,574 ****
--- 564,586 ----
      /*
       * Log a warning in case the proxy does not send the expected response.
       * Silently accept any response when the client expressed no expectation.
+      * 
+      * Don't pass through misleading 2xx replies. it confuses naive users and
+      * SMTP clients, and creates support problems.
       */
      if (expect != SMTPD_PROX_WANT_ANY && expect != *STR(state->proxy_buffer)) {
  	va_start(ap, fmt);
  	smtpd_proxy_cmd_error(state, fmt, ap);
  	va_end(ap);
+ 	if (*STR(state->proxy_buffer) == SMTPD_PROX_WANT_OK
+ 	    || *STR(state->proxy_buffer) == SMTPD_PROX_WANT_MORE) {
+ 	    state->error_mask |= MAIL_ERROR_SOFTWARE;
+ 	    state->err |= CLEANUP_STAT_PROXY;
+ 	    detail = cleanup_stat_detail(CLEANUP_STAT_PROXY);
+ 	    vstring_sprintf(state->proxy_buffer,
+ 			    "%d %s Error: %s",
+ 			    detail->smtp, detail->dsn, detail->text);
+ 	}
  	return (-1);
      } else {
  	return (0);