[nginx] Support for sendfile(SF_NOCACHE).

[Maxim Dounin]

details:   https://hg.nginx.org/nginx/rev/b002ad258f1d
branches:  
changeset: 7987:b002ad258f1d
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Mon Dec 27 19:49:26 2021 +0300
description:
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.

diffstat:

 src/core/ngx_output_chain.c              |  17 +++++++++++++----
 src/event/ngx_event_openssl.c            |   6 ++++++
 src/os/unix/ngx_freebsd_sendfile_chain.c |   6 ++++++
 3 files changed, 25 insertions(+), 4 deletions(-)

diffs (68 lines):

diff -r f1fcb0fe6975 -r b002ad258f1d src/core/ngx_output_chain.c
--- a/src/core/ngx_output_chain.c	Mon Dec 27 19:48:42 2021 +0300
+++ b/src/core/ngx_output_chain.c	Mon Dec 27 19:49:26 2021 +0300
@@ -256,10 +256,6 @@ ngx_output_chain_as_is(ngx_output_chain_
     }
 #endif
 
-    if (buf->in_file && buf->file->directio) {
-        return 0;
-    }
-
     sendfile = ctx->sendfile;
 
 #if (NGX_SENDFILE_LIMIT)
@@ -270,6 +266,19 @@ ngx_output_chain_as_is(ngx_output_chain_
 
 #endif
 
+#if !(NGX_HAVE_SENDFILE_NODISKIO)
+
+    /*
+     * With DIRECTIO, disable sendfile() unless sendfile(SF_NOCACHE)
+     * is available.
+     */
+
+    if (buf->in_file && buf->file->directio) {
+        sendfile = 0;
+    }
+
+#endif
+
     if (!sendfile) {
 
         if (!ngx_buf_in_memory(buf)) {
diff -r f1fcb0fe6975 -r b002ad258f1d src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c	Mon Dec 27 19:48:42 2021 +0300
+++ b/src/event/ngx_event_openssl.c	Mon Dec 27 19:49:26 2021 +0300
@@ -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 -r f1fcb0fe6975 -r b002ad258f1d src/os/unix/ngx_freebsd_sendfile_chain.c
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c	Mon Dec 27 19:48:42 2021 +0300
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c	Mon Dec 27 19:49:26 2021 +0300
@@ -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,