From: Willy Tarreau <w@1wt.eu>
Date: Wed, 19 Dec 2018 10:00:00 +0000 (+0100)
Subject: BUG/MEDIUM: stream-int: also wake the stream up on end of transfer
X-Git-Tag: v1.9.0~27
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=78f5ff86da1f60c71f3bd2ddc4eaed838aa76ed5;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: stream-int: also wake the stream up on end of transfer

There is an issue with some medium sized transfers occasionally not
shutting down at the end. Olivier tracked this to being caused by a
missing wakeup of process_stream(). What happens is that one of the
analysers sets CF_WAKE_WRITE to be woken up at the end of the transfer
to take note of the end of transaction, but a failed si_cs_send() at
the end of process_stream causes the call to be attempted again, with
CF_WAKE_WRITE lost. Then stream_int_notify() doesn't find any valid
condition to wake up process_stream(), and the stream stays there,
idling till the timeout.

In fact, CF_WAKE_WRITE has been designed for calling the analysers
to complete an operation without closing (keep-alive HTTP transfer
for instance). It only applies once the buffer is empty and there
is nothing left to be forwarded. In case the channel is closed, the
wakeup is already granted. So what we need here is to make sure to
wake process_stream() up in case the channel will not be closed and
it doesn't have anything left to be transferred. This is detected by
the lack of CF_AUTO_CLOSE and the emptiness of the buffer + to_forward
after a write activity. So now we take care of always waking the stream
up on end of transfers even if the analysers didn't subscribe to this
or if their subscription was lost.

CF_WAKE_WRITE should probably be killed now, though this first requires
careful inspection.

No backport is needed.

Cc: Olivier Houchard <ohouchard@haproxy.com>
Cc: Christopher Faulet <cfaulet@haproxy.com>
---

diff --git a/src/stream_interface.c b/src/stream_interface.c
index 6eb03be185..5283ed583e 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -520,7 +520,8 @@ void stream_int_notify(struct stream_interface *si)
 	    (oc->flags & (CF_WRITE_NULL|CF_WRITE_ERROR)) ||
 	    ((oc->flags & CF_WRITE_ACTIVITY) &&
 	     ((oc->flags & CF_SHUTW) ||
-	      ((oc->flags & CF_WAKE_WRITE) &&
+	      (((oc->flags & CF_WAKE_WRITE) ||
+		!(oc->flags & (CF_AUTO_CLOSE|CF_SHUTW_NOW|CF_SHUTW))) &&
 	       (sio->state != SI_ST_EST ||
 	        (channel_is_empty(oc) && !oc->to_forward)))))) {
 		task_wakeup(si_task(si), TASK_WOKEN_IO);