Fallback to synchronous sendfile() now only done on 3rd EBUSY without
any progress in a row. Not falling back is believed to be better
in case of occasional EBUSY, though protection is still needed to
make sure there will be no infinite loop.
This fixes content type set in stub_status and autoindex responses
to be usable in content type checks made by filter modules, such
as charset and sub filters.
There is no need to pass FLAG_FIN as a separate argument since it can always be
detected from the last_buf flag of the last frame buffer.
No functional changes.
Processing events from upstream connection can result in sending queued frames
from other streams. In this case such streams were not added to handling queue
and properly handled.
A global per connection flag was replaced by a per stream flag that indicates
currently sending stream while all other streams can be added to handling
queue.
Conditions for skipping ineligible peers are rewritten to make adding of new
conditions simpler and be in line with the "round_robin" and "least_conn"
modules. No functional changes.
Stricten response header checks: ensure that reserved bits are zeroes,
and that the opcode is "standard query".
Fixed the "zero-length domain name in DNS response" condition.
Renamed ngx_resolver_query_t to ngx_resolver_hdr_t as it describes
the header that is common to DNS queries and answers.
Replaced the magic number 12 by the size of the header structure.
The other changes are self-explanatory.
This flag in SPDY fake write events serves the same purposes as the "ready"
flag in real events, and it must be dropped if request needs to be handled.
Otherwise, it can prevent the request from finalization if ngx_http_writer()
was set, which results in a connection leak.
Found by Xiaochen Wang.
If c->read->ready was reset, but later some data were read from a socket
buffer due to a call to ngx_ssl_recv(), the c->read->ready flag should
be restored if not all data were read from OpenSSL buffers (as kernel
won't notify us about the data anymore).
More details are available here:
http://mailman.nginx.org/pipermail/nginx/2013-November/041178.html
The following new directives are introduced: proxy_cache_revalidate,
fastcgi_cache_revalidate, scgi_cache_revalidate, uwsgi_cache_revalidate.
Default is off. When set to on, they enable cache revalidation using
conditional requests with If-Modified-Since for expired cache items.
As of now, no attempts are made to merge headers given in a 304 response
during cache revalidation with headers previously stored in a cache item.
Headers in a 304 response are only used to calculate new validity time
of a cache item.
We should just call post_handler() when subrequest wants to read body, like
it happens for HTTP since rev. f458156fd46a. An attempt to init request body
for subrequests results in hang if the body was not already read.
