Hi, I referred EXT4_IOC_RESIZE_FS ioctl implementation in linux kernel ver 3.3.8. Implementation specifies tht Online shrinking is not supported. Code is as below. if (n_blocks_count < o_blocks_count) { /* On-line shrinking not supported */ ext4_warning(sb, "can't shrink FS - resize aborted"); return -EINVAL; } Can anyone please tell the reason why online shrinking is not supported. Thanks in adavance. Regards, Raphel