Mercurial > hg > nginx
view src/http/ngx_http_write_filter_module.c @ 7011:5e05118678af
Fixed background requests with asynchronous operations.
If the main request was finalized while a background request performed an
asynchronous operation, the main request ended up in ngx_http_writer() and was
not finalized until a network event or a timeout. For example, cache
background update with aio enabled made nginx unable to process further client
requests or close the connection, keeping it open until client closes it.
Now regular finalization of the main request is not suspended because of an
asynchronous operation in another request.
If a background request was terminated while an asynchronous operation was in
progress, background request's write event handler was changed to
ngx_http_request_finalizer() and never called again.
Now, whenever a request is terminated while an asynchronous operation is in
progress, connection error flag is set to make further finalizations of any
request with this connection lead to termination.
These issues appeared in 1aeaae6e9446 (not yet released).
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 29 May 2017 23:33:38 +0300 |
parents | f01ab2dbcfdc |
children | a7ff19afbb14 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static ngx_int_t ngx_http_write_filter_init(ngx_conf_t *cf); static ngx_http_module_t ngx_http_write_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_write_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL, /* merge location configuration */ }; ngx_module_t ngx_http_write_filter_module = { NGX_MODULE_V1, &ngx_http_write_filter_module_ctx, /* module context */ NULL, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; ngx_int_t ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in) { off_t size, sent, nsent, limit; ngx_uint_t last, flush, sync; ngx_msec_t delay; ngx_chain_t *cl, *ln, **ll, *chain; ngx_connection_t *c; ngx_http_core_loc_conf_t *clcf; c = r->connection; if (c->error) { return NGX_ERROR; } size = 0; flush = 0; sync = 0; last = 0; ll = &r->out; /* find the size, the flush point and the last link of the saved chain */ for (cl = r->out; cl; cl = cl->next) { ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write old buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", cl->buf->temporary, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last - cl->buf->pos, cl->buf->file_pos, cl->buf->file_last - cl->buf->file_pos); #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_ERROR; } #endif size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->sync) { sync = 1; } if (cl->buf->last_buf) { last = 1; } } /* add the new chain to the existent one */ for (ln = in; ln; ln = ln->next) { cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = ln->buf; *ll = cl; ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write new buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", cl->buf->temporary, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last - cl->buf->pos, cl->buf->file_pos, cl->buf->file_last - cl->buf->file_pos); #if 1 if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_ERROR; } #endif size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->sync) { sync = 1; } if (cl->buf->last_buf) { last = 1; } } *ll = NULL; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter: l:%ui f:%ui s:%O", last, flush, size); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); /* * avoid the output if there are no last buf, no flush point, * there are the incoming bufs and the size of all bufs * is smaller than "postpone_output" directive */ if (!last && !flush && in && size < (off_t) clcf->postpone_output) { return NGX_OK; } if (c->write->delayed) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (size == 0 && !(c->buffered & NGX_LOWLEVEL_BUFFERED) && !(last && c->need_last_buf)) { if (last || flush || sync) { for (cl = r->out; cl; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = NULL; c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, c->log, 0, "the http output chain is empty"); ngx_debug_point(); return NGX_ERROR; } if (r->limit_rate) { if (r->limit_rate_after == 0) { r->limit_rate_after = clcf->limit_rate_after; } limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1) - (c->sent - r->limit_rate_after); if (limit <= 0) { c->write->delayed = 1; delay = (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1); ngx_add_timer(c->write, delay); c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (clcf->sendfile_max_chunk && (off_t) clcf->sendfile_max_chunk < limit) { limit = clcf->sendfile_max_chunk; } } else { limit = clcf->sendfile_max_chunk; } sent = c->sent; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter limit %O", limit); chain = c->send_chain(c, r->out, limit); ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter %p", chain); if (chain == NGX_CHAIN_ERROR) { c->error = 1; return NGX_ERROR; } if (r->limit_rate) { nsent = c->sent; if (r->limit_rate_after) { sent -= r->limit_rate_after; if (sent < 0) { sent = 0; } nsent -= r->limit_rate_after; if (nsent < 0) { nsent = 0; } } delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate); if (delay > 0) { limit = 0; c->write->delayed = 1; ngx_add_timer(c->write, delay); } } if (limit && c->write->ready && c->sent - sent >= limit - (off_t) (2 * ngx_pagesize)) { c->write->delayed = 1; ngx_add_timer(c->write, 1); } for (cl = r->out; cl && cl != chain; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = chain; if (chain) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) { return NGX_AGAIN; } return NGX_OK; } static ngx_int_t ngx_http_write_filter_init(ngx_conf_t *cf) { ngx_http_top_body_filter = ngx_http_write_filter; return NGX_OK; }