From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751050Ab2LUFIb (ORCPT ); Fri, 21 Dec 2012 00:08:31 -0500 Received: from mail-qa0-f43.google.com ([209.85.216.43]:34561 "EHLO mail-qa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750752Ab2LUFIX convert rfc822-to-8bit (ORCPT ); Fri, 21 Dec 2012 00:08:23 -0500 X-Greylist: delayed 303 seconds by postgrey-1.27 at vger.kernel.org; Fri, 21 Dec 2012 00:08:23 EST MIME-Version: 1.0 In-Reply-To: References: <1353504311-6020-1-git-send-email-linkinjeon@gmail.com> <878v9f5ugn.fsf@devron.myhome.or.jp> <87k3sy17vk.fsf@devron.myhome.or.jp> <87txs0x45r.fsf@devron.myhome.or.jp> <87623ydnvq.fsf@devron.myhome.or.jp> Date: Fri, 21 Dec 2012 14:08:22 +0900 Message-ID: Subject: Re: [PATCH v5 7/8] fat (exportfs): rebuild directory-inode if fat_dget() fails From: Namjae Jeon To: OGAWA Hirofumi Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Namjae Jeon , Ravishankar N , Amit Sahrawat Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2012/12/21, Namjae Jeon : > 2012/12/20, OGAWA Hirofumi : >> Namjae Jeon writes: >> >>>> Okay, We will check how we can consolidate the 2 paths to avoid any >>>> issue. >>> Hi OGAWA. >>> >>> On checking fat_search_long() logic, it is observed that it performs >>> name based lookup of the entries in a given directory. >>> In fat_get_parent(), we do not have such information to use the >>> existing API to reconstruct the parent inode. >>> Could you give me some hint or guide to consolidate smoothly >>> fat_search_long and current traverse_logic ? >> >> Hm, start with copy of fat_search_long() and refactoring it. With it, we >> will be able to avoid the fixed bugs. >> >> After that, we might be able to merge those somehow. Well, I'm not >> pretty sure without doing it actually though. Hi OGAWA. When we checked to merge it with fat_search_long, we really did not find any possibility of code reusing for fat_traverse_cluster. It will not be proper. In case of fat_search_long()-> it is performing a name based lookup in a particular directory. While for reconnection with parent from NFS, we do not have the name of the parent directory. We are relying on ‘i_pos’ on disk position of directory entry. So, on first request for lookup for “..” (i.e if we call fat_search_long(child_dir->d_inode, MSDOS_DOTDOT,2,slot_info) it will return the directory entry for “..” itself. From this entry we can read the “log start” which is the starting cluster of the parent directory, but instead we need the “directory entry” where this is stored. So, from this level we need to go further one level up and read the parent ->parent-> cluster. After reading that cluster, we need to do a lookup of the “required ipos” in this directory block. i.e., if the path is A/B/C and we call the get_parent() from ‘C’. We need to read the directory block contents of ‘A’ and from those ‘directory entries' compare the log_start with the log_start value of B, which was obtained by doing a lookup “..” in C. So, Instead of it, we suggest we fix the “infinite-loop” condition in fat_traverse_logic and retain the code. of course, we will test it with corrupted FATfs. Please share your thoughts on this. Thanks. >> >> Thanks. >> -- >> OGAWA Hirofumi >> >