Does it work in the same fashion when grpid|bsdgroups option is set for EXT3/4?

Issue

• We've noticed that our RHEL 6 systems with ext4 file systems behave differently than our RHEL 5 systems with ext3 file systems in terms of ownership of new files and directories.

• Both seem to be compliant with POSIX.1 which allows either the Sys V behavior (group ID of new file is effective GID of process unless SGID bit is set, in which case new file gets GID of directory) or the BSD behavior (new file gets GID of directory even if SGID is not set).

• However there is a difference. ext3 behaves the Sys V way, and ext4 behaves the BSD way.

• We don't see the "grpid|bsdgroups" mount option set, which the mount(2) man page implies should be. Is this documented anywhere, perhaps it should be?