From fdd2000631b25fd964e94373488e7f94694d7020 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Mon, 25 Mar 2019 13:40:19 -0500
Subject: [PATCH] common/config: parse --default-$option as a default value

Sometimes it is useful to specify an alternative default value for an
option via the command line such that it has a lower priority than the
mon config database, config file, the rest of the command line, or the
environment.

Signed-off-by: Sage Weil <sage@redhat.com>
---
 qa/standalone/osd/osd-config.sh | 16 ++++++++++++++++
 src/common/config.cc            | 12 +++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/qa/standalone/osd/osd-config.sh b/qa/standalone/osd/osd-config.sh
index c850ecd35b9c5..126c2f7dee295 100755
--- a/qa/standalone/osd/osd-config.sh
+++ b/qa/standalone/osd/osd-config.sh
@@ -74,6 +74,22 @@ function TEST_config_track() {
     CEPH_ARGS='' ceph --admin-daemon $(get_asok_path osd.0) log reopen || return 1
 }
 
+function TEST_default_adjustment() {
+    a=$(ceph-osd --no-mon-config --show-config-value rgw_torrent_origin)
+    b=$(ceph-osd --no-mon-config --show-config-value rgw_torrent_origin --default-rgw-torrent-origin default)
+    c=$(ceph-osd --no-mon-config --show-config-value rgw_torrent_origin --default-rgw-torrent-origin arg)
+    [ "$a" != "default" ] || return 1
+    [ "$b" = "default" ] || return 1
+    [ "$c" = "arg" ] || return 1
+
+    a=$(ceph-osd --no-mon-config --show-config-value log_to_file)
+    b=$(ceph-osd --no-mon-config --show-config-value log_to_file --default-log-to-file=false)
+    c=$(ceph-osd --no-mon-config --show-config-value log_to_file --default-log-to-file=false --log-to-file)
+    [ "$a" = "true" ] || return 1
+    [ "$b" = "false" ] || return 1
+    [ "$c" = "true" ] || return 1
+}
+
 main osd-config "$@"
 
 # Local Variables:
diff --git a/src/common/config.cc b/src/common/config.cc
index 10f76d1bbb780..d1895a21c0b73 100644
--- a/src/common/config.cc
+++ b/src/common/config.cc
@@ -674,7 +674,17 @@ int md_config_t::parse_option(ConfigValues& values,
     std::string as_option("--");
     as_option += opt.name;
     option_name = opt.name;
-    if (opt.type == Option::TYPE_BOOL) {
+    if (ceph_argparse_witharg(
+	  args, i, &val, err,
+	  string(string("--default-") + opt.name).c_str(), (char*)NULL)) {
+      if (!err.str().empty()) {
+        error_message = err.str();
+	ret = -EINVAL;
+	break;
+      }
+      ret = _set_val(values, tracker,  val, opt, CONF_DEFAULT, &error_message);
+      break;
+    } else if (opt.type == Option::TYPE_BOOL) {
       int res;
       if (ceph_argparse_binary_flag(args, i, &res, oss, as_option.c_str(),
 				    (char*)NULL)) {
-- 
2.39.5