Mercurial > hg > nginx
view src/os/unix/ngx_linux_aio_read.c @ 7142:b9d919b53593 stable-1.12
Stream: relaxed next upstream condition (ticket #1317).
When switching to a next upstream, some buffers could be stuck in the middle
of the filter chain. A condition existed that raised an error when this
happened. As it turned out, this condition prevented switching to a next
upstream if ssl preread was used with the TCP protocol (see the ticket).
In fact, the condition does not make sense for TCP, since after successful
connection to an upstream switching to another upstream never happens. As for
UDP, the issue with stuck buffers is unlikely to happen, but is still possible.
Specifically, if a filter delays sending data to upstream.
The condition can be relaxed to only check the "buffered" bitmask of the
upstream connection. The new condition is simpler and fixes the ticket issue
as well. Additionally, the upstream_out chain is now reset for UDP prior to
connecting to a new upstream to prevent repeating the client data twice.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 11 Sep 2017 15:32:31 +0300 |
parents | f01ab2dbcfdc |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> extern int ngx_eventfd; extern aio_context_t ngx_aio_ctx; static void ngx_file_aio_event_handler(ngx_event_t *ev); static int io_submit(aio_context_t ctx, long n, struct iocb **paiocb) { return syscall(SYS_io_submit, ctx, n, paiocb); } ngx_int_t ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool) { ngx_event_aio_t *aio; aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t)); if (aio == NULL) { return NGX_ERROR; } aio->file = file; aio->fd = file->fd; aio->event.data = aio; aio->event.ready = 1; aio->event.log = file->log; file->aio = aio; return NGX_OK; } ssize_t ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset, ngx_pool_t *pool) { ngx_err_t err; struct iocb *piocb[1]; ngx_event_t *ev; ngx_event_aio_t *aio; if (!ngx_file_aio) { return ngx_read_file(file, buf, size, offset); } if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) { return NGX_ERROR; } aio = file->aio; ev = &aio->event; if (!ev->ready) { ngx_log_error(NGX_LOG_ALERT, file->log, 0, "second aio post for \"%V\"", &file->name); return NGX_AGAIN; } ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0, "aio complete:%d @%O:%uz %V", ev->complete, offset, size, &file->name); if (ev->complete) { ev->active = 0; ev->complete = 0; if (aio->res >= 0) { ngx_set_errno(0); return aio->res; } ngx_set_errno(-aio->res); ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno, "aio read \"%s\" failed", file->name.data); return NGX_ERROR; } ngx_memzero(&aio->aiocb, sizeof(struct iocb)); aio->aiocb.aio_data = (uint64_t) (uintptr_t) ev; aio->aiocb.aio_lio_opcode = IOCB_CMD_PREAD; aio->aiocb.aio_fildes = file->fd; aio->aiocb.aio_buf = (uint64_t) (uintptr_t) buf; aio->aiocb.aio_nbytes = size; aio->aiocb.aio_offset = offset; aio->aiocb.aio_flags = IOCB_FLAG_RESFD; aio->aiocb.aio_resfd = ngx_eventfd; ev->handler = ngx_file_aio_event_handler; piocb[0] = &aio->aiocb; if (io_submit(ngx_aio_ctx, 1, piocb) == 1) { ev->active = 1; ev->ready = 0; ev->complete = 0; return NGX_AGAIN; } err = ngx_errno; if (err == NGX_EAGAIN) { return ngx_read_file(file, buf, size, offset); } ngx_log_error(NGX_LOG_CRIT, file->log, err, "io_submit(\"%V\") failed", &file->name); if (err == NGX_ENOSYS) { ngx_file_aio = 0; return ngx_read_file(file, buf, size, offset); } return NGX_ERROR; } static void ngx_file_aio_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; aio = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0, "aio event handler fd:%d %V", aio->fd, &aio->file->name); aio->handler(ev); }