Hi, > -- > 2.21.0 Won't this break 'chattr' on files that already have this flag set? FS_IOC_GETFLAGS will return this flag, so 'chattr' will pass it back to FS_IOC_SETFLAGS which will return EOPNOTSUPP due to this: if (ext4_mask_flags(inode->i_mode, flags) != flags) return -EOPNOTSUPP; >>>> You are right for this and we also need take care of this in EXT4_IOC_FSSETXATTR/ this is a bit strange behavior as chattr read existed flags but could not set them again, there are several possible ways that I could think of to fix the issue? 1) change chattr to filter Project inherit bit before call FS_IOC_SETFLAGS 2) we automatically fixed the flag before mask check, something like: if reg: flags &= ~PROJECT_INHERT; if (ext4_mask_flags(inode->i_mode, flags) != flags) return -EOPNOTSUPP; But this might be not good.. I would prefer solution 1) What do you think?