From: Andreas Dilger Subject: Re: Do we really need parallel resizer? Date: Sat, 25 Jun 2011 10:42:48 -0600 Message-ID: <606DB4F9-C7D5-4853-B1FB-CF15E96AC037@gmail.com> References: Mime-Version: 1.0 (iPhone Mail 8J2) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: "adilger@dilger.ca" , Ext4 Developers List To: Yongqiang Yang Return-path: Received: from mail-pz0-f51.google.com ([209.85.210.51]:36671 "EHLO mail-pz0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751067Ab1FYQme convert rfc822-to-8bit (ORCPT ); Sat, 25 Jun 2011 12:42:34 -0400 Received: by pzk26 with SMTP id 26so2398428pzk.10 for ; Sat, 25 Jun 2011 09:42:33 -0700 (PDT) In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: I don't care particularly about parallel resize being a common usage. My only concern is to prevent filesystem corruption in case it happens by accident. I'm not sure why you think it is better to have a flag to indicate resize in progress instead of just having a lock. If you could please explain the benefit of this then it is possible to make a decision on why this code should be changed. Cheers, Andreas On 2011-06-24, at 8:17 PM, Yongqiang Yang wrote: > On Fri, Jun 24, 2011 at 4:41 PM, Yongqiang Yang wrote: >> Hi Andreas, >> >> I noticed that resize is protected by resize_lock. Then parallel >> resizer works. However, I think there is no need to make parallel >> resizer work. >> >> I think we can use an atomic integer 'resize_flag' instead of >> resize_lock, resize_flag is set to 1 before the kernel does resizing >> work, while resize_flag is set to 0 after the kernel finishes >> resizing work. Resizing is allowed only if resize_flag is 0. If >> resize_flag is 1, kernel returns -EBUSY to userspace. > Sorry, I made an error. we should use an integer protected by resize_lock. > > Yongqiang. >> >> What about your opinion? >> >> Yongqiang. >> >> -- >> Best Wishes >> Yongqiang Yang >> > > > > -- > Best Wishes > Yongqiang Yang