From: Yongqiang Yang Subject: [PATCH V6 RESEND] ext4: add new online resize Date: Fri, 30 Dec 2011 18:59:57 +0800 Message-ID: <1325242812-27005-1-git-send-email-xiaoqiangnk@gmail.com> Cc: linux-ext4@vger.kernel.org To: tytso@mit.edu Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:41000 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750877Ab1L3Old (ORCPT ); Fri, 30 Dec 2011 09:41:33 -0500 Received: by iaeh11 with SMTP id h11so25397943iae.19 for ; Fri, 30 Dec 2011 06:41:32 -0800 (PST) Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi all, Here is the 6th veriosn of patch series adding new resize implementation to ext4. -- What's new resize implementation? It is a new online resize interface for ext4. It can be used via ioctl with EXT4_IOC_RESIZE_FS and a 64 bit integer indicating size of the resized fs in block. -- Difference between current resize and new resize. New resize lets kernel do all work, like allocating bitmaps and inode tables and can support flex_bg and BLOCK_UNINIT features. Besides these, new resize is much faster than current resize. Below are benchmarks I made on my personal computer, fses with flex_bg size = 16 were resized to 230GB evry time. The first row shows the size of a fs from which the fs was resized to 230GB. The datas were collected by 'time resize2fs'. new resize 20GB 50GB 100GB real 0m3.558s 0m2.891s 0m0.394s user 0m0.004s 0m0.000s 0m0.394s sys 0m0.048s 0m0.048s 0m0.028s current resize 20GB 50GB 100GB real 5m2.770s 4m43.757s 3m14.840s user 0m0.040s 0m0.032s 0m0.024s sys 0m0.464s 0m0.432s 0m0.324s According to data above, new resize is faster than current resize in both user and sys time. New resize performs well in sys time, because it supports BLOCK_UNINIT and adds multi-groups each time. -- About supporting new features. YES! New resize can support new feature like bigalloc and exclude bitmap easily. Because it lets kernel do all work. V5->V6: add code initializing inode bitmap and inode tables back. V4->V5: release resizing error lock in error case of IOC_RESIZEFS Thanks Djalal for pointing it out and his patch for IOC_GROUP_EXTEND and IOC_GROUP_ADD. V3->V4: rename __ext4_group_extend to ext4_group_extend_no_check V2->V3: initialize block bitmap of last group. remove code initializing inode bitmap and inode tables. Yongqiang.