Merge of r4416:

Fixed AIO error handling on FreeBSD.

The aio_return() must be called regardless of the error returned by
aio_error().  Not calling it resulted in various problems up to segmentation
faults (as AIO events are level-triggered and were reported again and again).

Additionally, in "aio sendfile" case r->blocked was incremented in case of
error returned from ngx_file_aio_read(), thus causing request hangs.

src/http/ngx_http_copy_filter_module.c

diff --git a/src/http/ngx_http_copy_filter_module.c b/src/http/ngx_http_copy_filter_module.c
index 2d197c6..d52fbeb 100644
--- a/src/http/ngx_http_copy_filter_module.c
+++ b/src/http/ngx_http_copy_filter_module.c
@@ -190,7 +190,7 @@
 
             rc = n;
 
-            if (file->aio) {
+            if (rc == NGX_AGAIN) {
                 file->aio->data = r;
                 file->aio->handler = ngx_http_copy_aio_sendfile_event_handler;
 

src/os/unix/ngx_file_aio_read.c

diff --git a/src/os/unix/ngx_file_aio_read.c b/src/os/unix/ngx_file_aio_read.c
index 5973b5b..0bb383d 100644
--- a/src/os/unix/ngx_file_aio_read.c
+++ b/src/os/unix/ngx_file_aio_read.c
@@ -157,24 +157,15 @@
         return NGX_ERROR;
     }
 
-    if (n != 0) {
-        if (n == NGX_EINPROGRESS) {
-            if (ev->ready) {
-                ev->ready = 0;
-                ngx_log_error(NGX_LOG_ALERT, file->log, n,
-                              "aio_read(\"%V\") still in progress",
-                              &file->name);
-            }
-
-            return NGX_AGAIN;
+    if (n == NGX_EINPROGRESS) {
+        if (ev->ready) {
+            ev->ready = 0;
+            ngx_log_error(NGX_LOG_ALERT, file->log, n,
+                          "aio_read(\"%V\") still in progress",
+                          &file->name);
         }
 
-        aio->err = n;
-        ev->ready = 0;
-
-        ngx_log_error(NGX_LOG_CRIT, file->log, n,
-                      "aio_read(\"%V\") failed", &file->name);
-        return NGX_ERROR;
+        return NGX_AGAIN;
     }
 
     n = aio_return(&aio->aiocb);
@@ -182,9 +173,9 @@
     if (n == -1) {
         err = ngx_errno;
         aio->err = err;
-        ev->ready = 0;
+        ev->ready = 1;
 
-        ngx_log_error(NGX_LOG_ALERT, file->log, err,
+        ngx_log_error(NGX_LOG_CRIT, file->log, err,
                       "aio_return(\"%V\") failed", &file->name);
         return NGX_ERROR;
     }