From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 5/7 v2] ext4: track all extent status in extent status tree Date: Tue, 22 Jan 2013 23:31:16 -0500 Message-ID: <20130123043116.GD21696@thunk.org> References: <1357901627-3068-1-git-send-email-wenqing.lz@taobao.com> <1357901627-3068-6-git-send-email-wenqing.lz@taobao.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Jan kara , Zheng Liu To: Zheng Liu Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:44957 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732Ab3AWEbX (ORCPT ); Tue, 22 Jan 2013 23:31:23 -0500 Content-Disposition: inline In-Reply-To: <1357901627-3068-6-git-send-email-wenqing.lz@taobao.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Jan 11, 2013 at 06:53:45PM +0800, Zheng Liu wrote: > From: Zheng Liu > Please line-wrap the commit description to 72 columns. (This way the output of "git log" will look nice even on 80 column terminal windows)". > After record phycisal block and status, extent status tree is able to track the "By recording the physical block and status, ...." > status of every extents. When we call _map_blocks functions to lookup an extent > or create a new written/unwritten/delayed extent, this extent will be inserted > into extent status tree. > > We don't load all extents from disk in alloc_inode() because it costs too much > memory, and, when open/close a file very frequently, it will takes too much time "...and if a file is opened and closed frequently"..." > to load all extent information. So currently when we create/lookup an extent, > this extent will be inserted into extent status tree. Hence, the status in > extent status tree might be not completely. "Hence, the extent status tree may not comprehensively contain all of the extents found in the file." - Ted