[PATCH 4 of 4] Support for sendfile(SF_NOCACHE)

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1636603897 -10800
#      Thu Nov 11 07:11:37 2021 +0300
# Node ID 10f96e74ae73e1c53a3fd08e7e1c26754c8969ed
# Parent  98d3beb63f32cbb68d1cdcec385614d32129cad0
Support for sendfile(SF_NOCACHE).

The SF_NOCACHE flag, introduced in FreeBSD 11 along with the new non-blocking
sendfile() implementation by glebius@, makes it possible to use sendfile()
along with the "directio" directive.

diff --git a/src/core/ngx_output_chain.c b/src/core/ngx_output_chain.c
--- a/src/core/ngx_output_chain.c
+++ b/src/core/ngx_output_chain.c
@@ -256,9 +256,11 @@ ngx_output_chain_as_is(ngx_output_chain_
     }
 #endif
 
+#if !(NGX_HAVE_SENDFILE_NODISKIO)
     if (buf->in_file && buf->file->directio) {
         return 0;
     }
+#endif
 
     sendfile = ctx->sendfile;
 
diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -2955,7 +2955,13 @@ ngx_ssl_sendfile(ngx_connection_t *c, ng
     ngx_set_errno(0);
 
 #if (NGX_HAVE_SENDFILE_NODISKIO)
+
     flags = (c->busy_count <= 2) ? SF_NODISKIO : 0;
+
+    if (file->file->directio) {
+        flags |= SF_NOCACHE;
+    }
+
 #else
     flags = 0;
 #endif
diff --git a/src/os/unix/ngx_freebsd_sendfile_chain.c b/src/os/unix/ngx_freebsd_sendfile_chain.c
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -174,7 +174,13 @@ ngx_freebsd_sendfile_chain(ngx_connectio
             sent = 0;
 
 #if (NGX_HAVE_SENDFILE_NODISKIO)
+
             flags = (c->busy_count <= 2) ? SF_NODISKIO : 0;
+
+            if (file->file->directio) {
+                flags |= SF_NOCACHE;
+            }
+
 #endif
 
             rc = sendfile(file->file->fd, c->fd, file->file_pos,