[PATCH 4 of 4] AIO operations now add timers (ticket #2162)

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1701050170 -10800
#      Mon Nov 27 04:56:10 2023 +0300
# Node ID 00c3e7333145ddb5ea0eeaaa66b3d9c26973c9c2
# Parent  61d08e4cf97cc073200ec32fc6ada9a2d48ffe51
AIO operations now add timers (ticket #2162).

Each AIO (thread IO) operation being run is now accompanied with 1-minute
timer.  This timer prevents unexpected shutdown of the worker process while
an AIO operation is running, and logs an alert if the operation is running
for too long.

This fixes "open socket left" alerts during worker processes shutdown
due to pending AIO (or thread IO) operations while corresponding requests
have no timers.  In particular, such errors were observed while reading
cache headers (ticket #2162), and with worker_shutdown_timeout.

diff --git a/src/http/ngx_http_copy_filter_module.c b/src/http/ngx_http_copy_filter_module.c
--- a/src/http/ngx_http_copy_filter_module.c
+++ b/src/http/ngx_http_copy_filter_module.c
@@ -170,6 +170,8 @@ ngx_http_copy_aio_handler(ngx_output_cha
     file->aio->data = r;
     file->aio->handler = ngx_http_copy_aio_event_handler;
 
+    ngx_add_timer(&file->aio->event, 60000);
+
     r->main->blocked++;
     r->aio = 1;
     ctx->aio = 1;
@@ -192,6 +194,17 @@ ngx_http_copy_aio_event_handler(ngx_even
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http aio: \"%V?%V\"", &r->uri, &r->args);
 
+    if (ev->timedout) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
+                      "aio operation took too long");
+        ev->timedout = 0;
+        return;
+    }
+
+    if (ev->timer_set) {
+        ngx_del_timer(ev);
+    }
+
     r->main->blocked--;
     r->aio = 0;
 
@@ -273,6 +286,8 @@ ngx_http_copy_thread_handler(ngx_thread_
         return NGX_ERROR;
     }
 
+    ngx_add_timer(&task->event, 60000);
+
     r->main->blocked++;
     r->aio = 1;
 
@@ -297,6 +312,17 @@ ngx_http_copy_thread_event_handler(ngx_e
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http thread: \"%V?%V\"", &r->uri, &r->args);
 
+    if (ev->timedout) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
+                      "thread operation took too long");
+        ev->timedout = 0;
+        return;
+    }
+
+    if (ev->timer_set) {
+        ngx_del_timer(ev);
+    }
+
     r->main->blocked--;
     r->aio = 0;
 
diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -705,6 +705,8 @@ ngx_http_file_cache_aio_read(ngx_http_re
         c->file.aio->data = r;
         c->file.aio->handler = ngx_http_cache_aio_event_handler;
 
+        ngx_add_timer(&c->file.aio->event, 60000);
+
         r->main->blocked++;
         r->aio = 1;
 
@@ -752,6 +754,17 @@ ngx_http_cache_aio_event_handler(ngx_eve
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http file cache aio: \"%V?%V\"", &r->uri, &r->args);
 
+    if (ev->timedout) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
+                      "aio operation took too long");
+        ev->timedout = 0;
+        return;
+    }
+
+    if (ev->timer_set) {
+        ngx_del_timer(ev);
+    }
+
     r->main->blocked--;
     r->aio = 0;
 
@@ -810,6 +823,8 @@ ngx_http_cache_thread_handler(ngx_thread
         return NGX_ERROR;
     }
 
+    ngx_add_timer(&task->event, 60000);
+
     r->main->blocked++;
     r->aio = 1;
 
@@ -831,6 +846,17 @@ ngx_http_cache_thread_event_handler(ngx_
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http file cache thread: \"%V?%V\"", &r->uri, &r->args);
 
+    if (ev->timedout) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
+                      "thread operation took too long");
+        ev->timedout = 0;
+        return;
+    }
+
+    if (ev->timer_set) {
+        ngx_del_timer(ev);
+    }
+
     r->main->blocked--;
     r->aio = 0;
 
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -3949,6 +3949,8 @@ ngx_http_upstream_thread_handler(ngx_thr
     r->aio = 1;
     p->aio = 1;
 
+    ngx_add_timer(&task->event, 60000);
+
     return NGX_OK;
 }
 
@@ -3967,6 +3969,17 @@ ngx_http_upstream_thread_event_handler(n
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http upstream thread: \"%V?%V\"", &r->uri, &r->args);
 
+    if (ev->timedout) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
+                      "thread operation took too long");
+        ev->timedout = 0;
+        return;
+    }
+
+    if (ev->timer_set) {
+        ngx_del_timer(ev);
+    }
+
     r->main->blocked--;
     r->aio = 0;
 
diff --git a/src/os/unix/ngx_files.c b/src/os/unix/ngx_files.c
--- a/src/os/unix/ngx_files.c
+++ b/src/os/unix/ngx_files.c
@@ -110,6 +110,8 @@ ngx_thread_read(ngx_file_t *file, u_char
             return NGX_ERROR;
         }
 
+        task->event.log = file->log;
+
         file->thread_task = task;
     }
 
@@ -493,6 +495,8 @@ ngx_thread_write_chain_to_file(ngx_file_
             return NGX_ERROR;
         }
 
+        task->event.log = file->log;
+
         file->thread_task = task;
     }
 
diff --git a/src/os/unix/ngx_linux_sendfile_chain.c b/src/os/unix/ngx_linux_sendfile_chain.c
--- a/src/os/unix/ngx_linux_sendfile_chain.c
+++ b/src/os/unix/ngx_linux_sendfile_chain.c
@@ -332,6 +332,7 @@ ngx_linux_sendfile_thread(ngx_connection
             return NGX_ERROR;
         }
 
+        task->event.log = c->log;
         task->handler = ngx_linux_sendfile_thread_handler;
 
         c->sendfile_task = task;