SB_NOSEC
fc->sb_flags |= SB_NOSEC;
fm->sb->s_flags |= SB_NOSEC;
sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
sb->s_flags |= SB_NOSEC;
sb->s_flags = (sb->s_flags & ~(SB_POSIXACL | SB_NOSEC)) |
if (upper_mnt->mnt_sb->s_flags & SB_NOSEC)
sb->s_flags |= SB_NOSEC;
fc->sb_flags |= SB_NOSEC;
if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & SB_NOSEC))
sb->s_flags |= SB_NOSEC;