tree d343a53947957aecc23a4cd104332f2777bf1c4f
parent 8283d59bd7edc65edbf17e2ca46a237ab6cc2f8c
author Aurelien DARRAGON <adarragon@haproxy.com> 1675769787 +0100
committer Christopher Faulet <cfaulet@haproxy.com> 1690186672 +0200

BUG/MEDIUM: listener/proxy: fix listeners notify for proxy resume

In 58651b42f ("MEDIUM: listener/proxy: make the listeners notify about
proxy pause/resume") we introduced the logic for pause/resume notify using
li_ready for pause and li_paused for resume.

Unfortunately, relying on li_paused for resume doesn't work reliably if we
resume a listener which is only made of receivers that are completely stopped.
For example, this could happen with receivers that don't support the
LI_PAUSED state like ABNS sockets.

This is especially true since pause_listener() was renamed to
suspend_listener() to better reflect its actual behavior in
("MINOR: listener:  pause_listener() becomes suspend_listener())

To fix this, we now rely on the li_suspended state in resume_listener() to make
sure that suspend_listener() and resume_listener() notify messages are
consistent to each other:

"Proxy pause" is triggered when there are no more ready listeners.
"Proxy resume" is triggered when there are no more suspended listeners.

Also, we make use of the new PR_FL_PAUSED proxy flag to make sure we don't
report the same event twice.

This could be backported up to 2.4 after a reasonable observation
period to make sure that this change doesn't cause unwanted side-effects.

--
Backport notes:

This commit depends on:
 - "MINOR: listener: pause_listener() becomes suspend_listener()"

-> 2.4 only, as "MINOR: proxy/listener: support for additional PAUSED state"
was not backported:

Replace this:

    |+       if (px && !(px->flags & PR_FL_PAUSED) && !px->li_ready) {
    |                /* PROXY_LOCK is required */
    |                proxy_cond_pause(px);
    |                ha_warning("Paused %s %s.\n", proxy_cap_str(px->cap), px->id);

By this:

    |+       if (px && !px->li_ready) {
    |                ha_warning("Paused %s %s.\n", proxy_cap_str(px->cap), px->id);
    |                send_log(px, LOG_WARNING, "Paused %s %s.\n", proxy_cap_str(px->cap), px->id);
    |        }

And this:

    |+       if (px && (px->flags & PR_FL_PAUSED) && !px->li_suspended) {
    |                /* PROXY_LOCK is required */
    |                proxy_cond_resume(px);
    |                ha_warning("Resumed %s %s.\n", proxy_cap_str(px->cap), px->id);

By this:

    |+       if (px && !px->li_suspended) {
    |                ha_warning("Resumed %s %s.\n", proxy_cap_str(px->cap), px->id);
    |                send_log(px, LOG_WARNING, "Resumed %s %s.\n", proxy_cap_str(px->cap), px->id);
    |        }

(cherry picked from commit ca8a4b2966161c881deb22d9972d1a299a12aa29)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 4ea8583c0ce483da15c3876e6f85ef37afc82c71)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit fa46e7c338e80e06b73058bc4128da4533601fc8)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit a923d00426f2231b8e8e8006292efbbc5b0d190f)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>