conn->want conversion: Fix fuse_apply_conn_info_opts()

fuse_apply_conn_info_opts() was applying to 'want_ext',
which would cause conflicts with 'want' if the application
applied its own flags to 'conn->want'.

Solution is:
    - to move fuse_{set,unset,get}_feature_flag and
      convert_to_conn_want_ext() to fuse_lowlevel.c and
      to define them as part of the public API, although
      convert_to_conn_want_ext() should not be used - it is
      currently needed to be a public function due as it needs
      to be defined for the tests.

Related to https://github.com/libfuse/libfuse/issues/1171 and
https://github.com/libfuse/libfuse/pull/1172.

Closes: https://github.com/libfuse/libfuse/issues/1171
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
(cherry picked from commit baadab0492a495fda98216b351976d2e5d6d0866)

1 files changed, 31 insertions, 19 deletions

diff --git a/include/fuse_common.h b/include/fuse_common.h
index 582505f..dd08f44 100644
--- a/include/fuse_common.h
+++ b/include/fuse_common.h
@@ -1096,28 +1096,40 @@ void fuse_loop_cfg_convert(struct fuse_loop_config *config,
 			   struct fuse_loop_config_v1 *v1_conf);
 #endif
 
+/**
+ * Set a feature flag in the want_ext field of fuse_conn_info.
+ *
+ * @param conn connection information
+ * @param flag feature flag to be set
+ * @return true if the flag was set, false if the flag is not supported
+ */
+bool fuse_set_feature_flag(struct fuse_conn_info *conn, uint64_t flag);
 
-static inline bool fuse_set_feature_flag(struct fuse_conn_info *conn,
-					 uint64_t flag)
-{
-	if (conn->capable_ext & flag) {
-		conn->want_ext |= flag;
-		return true;
-	}
-	return false;
-}
+/**
+ * Unset a feature flag in the want_ext field of fuse_conn_info.
+ *
+ * @param conn connection information
+ * @param flag feature flag to be unset
+ */
+void fuse_unset_feature_flag(struct fuse_conn_info *conn, uint64_t flag);
+
+/**
+ * Get the value of a feature flag in the want_ext field of fuse_conn_info.
+ *
+ * @param conn connection information
+ * @param flag feature flag to be checked
+ * @return true if the flag is set, false otherwise
+ */
+bool fuse_get_feature_flag(struct fuse_conn_info *conn, uint64_t flag);
+
+/*
+ * DO NOT USE: Not part of public API, for internal test use only.
+ * The function signature or any use of it is not guaranteeed to
+ * remain stable. And neither are results of what this function does.
+ */
+int fuse_convert_to_conn_want_ext(struct fuse_conn_info *conn);
 
-static inline void fuse_unset_feature_flag(struct fuse_conn_info *conn,
-					 uint64_t flag)
-{
-	conn->want_ext &= ~flag;
-}
 
-static inline bool fuse_get_feature_flag(struct fuse_conn_info *conn,
-					     uint64_t flag)
-{
-	return conn->capable_ext & flag ? true : false;
-}
 
 /* ----------------------------------------------------------- *
  * Compatibility stuff					       *