.

fuse/server.go

@@ -246,17 +246,6 @@ func NewServer(fs RawFileSystem, mountPoint string, opts *MountOptions) (*Server
 }
 
 func escapeComma(optionValue string) string {
-    // Perhaps if clause isn't even needed.
-    // We need to loop through each character of the string
-    // anyway, so we'll catch each comma anyway.
-    //
-    // Maybe it's very slightly more performant if we initially
-    // test if it contains a ','?
-    //
-    // But perhaps strings.Replace() is equally fast..
-
-    // if strings.Contains(s, ",") {}
-
     return strings.Replace(optionValue, ",", "//", -1)
 }
 
@@ -282,7 +271,11 @@ func (o *MountOptions) optionsStrings() []string {
 		r = append(r, "daemon_timeout=0")
 	}
 
+	// Commas in an option need to be escaped, because
+	// options are separated by a comma.
 	var rEscaped []string
+	bool escape_ok = begins_with(s, fsname_str) ||
+				 begins_with(s, subtype_str);
 	for _, s := range r {
 		rEscaped = append(rEscaped, escapeComma(s))
 	}

notes

+we try to implement the following commits in libfuse in go-fuse:
+
+	https://github.com/libfuse/libfuse/commit/555d6b504308eac6b976321ce938ee4bec62c354
+	https://github.com/libfuse/libfuse/commit/28bdae3d113ef479c1660a581ef720cdc33bf466 (???)
+
+
+core code in libfuse where commas are escaped:
+	inside the function `add_opt_common`:
+
+	https://github.com/libfuse/libfuse/blob/db35a37de/lib/fuse_opt.c
+
+so it only happens if 'esc' (=escape) is true
+
+=> then there are two functions:
+
+- fuse_opt_add_opt
+- fuse_opt_add_opt_escaped
+
+the first function is called if we want to add an option which shouldn't be escapd
+the second function is called if we want to add an option which should be escapd
+
+Those functions are called in mount.c/fuse_mount_opt_proc
+
+	https://github.com/libfuse/libfuse/blob/dba6b3983/lib/mount.c#L187-L216
+
+	=> for fusermount options they always use 'fuse_opt_add_opt_escaped'
+	=> so it seems to be safe to escape any option, because in this patch
+           it's only about fusermount options anyway
+
+which on the other hand is called here (it's passed as 'proc'):
+
+	https://github.com/libfuse/libfuse/blob/db35a37def14b72181f3630efeea0e0433103c41/lib/fuse_opt.c#L398-L423