Hello! On Mon, Jul 24, 2017 at 10:08:20AM +0000, Eran Kornblau wrote:
> Hi Roman, > > I got a GitHub issue opened few days ago, that my module doesn't work > following this commit - > https://github.com/kaltura/nginx-vod-module/issues/645#issuecomment-317027706 > > The situation is as follows - > 1. My module's content phase handler runs and performs an async read request - > a. It calls ngx_file_aio_read which returns NGX_AGAIN > b. Increments r->blocked > c. Sets r->aio to 1 > (code here - > https://github.com/kaltura/nginx-vod-module/blob/master/ngx_file_reader.c#L392) > 2. The NGX_AGAIN status propagates up to ngx_http_core_content_phase which > calls ngx_http_finalize_request > with this status. > 3. r->buffered, c->buffered, and r->postponed are all false, so this if: > > https://github.com/nginx/nginx/blob/master/src/http/ngx_http_request.c#L2456 > is skipped (it used to enter before the patch since r->blocked is 1) > In addition, r == c->data, so at the end, ngx_http_finalize_request > calls ngx_http_finalize_connection > 4. Since r->main->count == 1 and r->keepalive == 1, this function calls > ngx_http_set_keepalive > 5. ngx_http_set_keepalive calls ngx_http_free_request which destroys the pool > even though it has aio pending. > > Please let me know if you think I'm doing something wrong here (I can, for > example, increment r->main->count, > but this is not done in any of the other places that do blocked++) The NGX_AGAIN returned from a content phase handler when you started an AIO operation looks wrong: it means that nginx is already writing a response and was blocked by a full socket buffer. In this case nginx will assume it should continue writing based on socket's write events, and will close the connection as long as everything is written (no r->buffered, c->buffered is set). Before the Roman's patch the situation was the same: there is not r->blocking check in ngx_http_writer(), so it would close the connection as long as a write event happen for some reason. Rather, you should use NGX_DONE and increment r->count if you want to wait for an AIO operation result and continue processing yourself. [...] -- Maxim Dounin http://nginx.org/ _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel
