diff --git a/lib/bundler/rubygems_ext.rb b/lib/bundler/rubygems_ext.rb
index 14f10af9d7..547102be41 100644
--- a/lib/bundler/rubygems_ext.rb
+++ b/lib/bundler/rubygems_ext.rb
@@ -36,15 +36,14 @@ module Gem
       remove_method :open_file_with_flock if Gem.respond_to?(:open_file_with_flock)
 
       def open_file_with_flock(path, &block)
-        mode = IO::RDONLY | IO::APPEND | IO::CREAT | IO::BINARY
+        # read-write mode is used rather than read-only in order to support NFS
+        mode = IO::RDWR | IO::APPEND | IO::CREAT | IO::BINARY
         mode |= IO::SHARE_DELETE if IO.const_defined?(:SHARE_DELETE)
 
         File.open(path, mode) do |io|
           begin
             io.flock(File::LOCK_EX)
           rescue Errno::ENOSYS, Errno::ENOTSUP
-          rescue Errno::ENOLCK # NFS
-            raise unless Thread.main == Thread.current
           end
           yield io
         end
diff --git a/lib/rubygems.rb b/lib/rubygems.rb
index 43c0d8f13c..8c3e8bdc68 100644
--- a/lib/rubygems.rb
+++ b/lib/rubygems.rb
@@ -808,15 +808,14 @@ An Array (#{env.inspect}) was passed in from #{caller[3]}
   # Open a file with given flags, and protect access with flock
 
   def self.open_file_with_flock(path, &block)
-    mode = IO::RDONLY | IO::APPEND | IO::CREAT | IO::BINARY
+    # read-write mode is used rather than read-only in order to support NFS
+    mode = IO::RDWR | IO::APPEND | IO::CREAT | IO::BINARY
     mode |= IO::SHARE_DELETE if IO.const_defined?(:SHARE_DELETE)
 
     File.open(path, mode) do |io|
       begin
         io.flock(File::LOCK_EX)
       rescue Errno::ENOSYS, Errno::ENOTSUP
-      rescue Errno::ENOLCK # NFS
-        raise unless Thread.main == Thread.current
       end
       yield io
     end