From 4704104049dfe65b851ec3e434b76907400e9fe3 Mon Sep 17 00:00:00 2001
From: Kim Alvefur <zash@zash.se>
Date: Thu, 18 Nov 2021 16:21:43 +0100
Subject: net.server_epoll: Try harder to avoid reentrant opportunistic writes
Opportunistic writes sure do complicate things. This is especially
intended to avoid opportunistic_writes from within the onpredrain
callback.
---
net/server_epoll.lua | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/server_epoll.lua b/net/server_epoll.lua
index 0a0f89c5..8a70e2dc 100644
--- a/net/server_epoll.lua
+++ b/net/server_epoll.lua
@@ -487,6 +487,7 @@ end
-- Called when socket is writable
function interface:onwritable()
+ self._writing = true; -- prevent reentrant writes etc
self:onconnect();
if not self.conn then return; end -- could have been closed in onconnect
self:on("predrain");
@@ -514,6 +515,7 @@ function interface:onwritable()
end
self:setwritetimeout(false);
self:ondrain(); -- Be aware of writes in ondrain
+ self._writing = nil;
return ok;
elseif partial then
self:debug("Sent %d out of %d buffered bytes", partial, #data);
@@ -528,6 +530,7 @@ function interface:onwritable()
self:set(nil, true);
self:setwritetimeout();
end
+ self._writing = nil;
if err == "wantwrite" or err == "timeout" then
self:set(nil, true);
self:setwritetimeout();
@@ -557,7 +560,7 @@ function interface:write(data)
elseif buffer == nil then
self.writebuffer = data;
end
- if not self._write_lock then
+ if not self._write_lock and not self._writing then
if self._writable and cfg.opportunistic_writes and not self._opportunistic_write then
self._opportunistic_write = true;
local ret, err = self:onwritable();
--
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