FS_UPD_CMTIME
case FS_UPD_CMTIME:
ret = inode->i_op->update_time(inode, FS_UPD_CMTIME, flags);
ret = generic_update_time(inode, FS_UPD_CMTIME, flags);
inode_update_time(inode, FS_UPD_CMTIME, 0);