Add project feature flag EXT4_FEATURE_RO_COMPAT_PROJECT

This patch add project feature flag EXT4_FEATURE_RO_COMPAT_PROJECT.
Project feature is a read-only compat feature. Thus, an ext4 file
system with project feature enabled could only be read by ext4
kernel module without project feature support.

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
6 files changed