Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933423AbdC3MDV (ORCPT ); Thu, 30 Mar 2017 08:03:21 -0400 Received: from mga01.intel.com ([192.55.52.88]:11168 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933099AbdC3MDT (ORCPT ); Thu, 30 Mar 2017 08:03:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,246,1486454400"; d="scan'208";a="949772788" Subject: Re: [PATCH] ubifs: Fix O_TMPFILE corner case in ubifs_link() To: Richard Weinberger , linux-mtd@lists.infradead.org References: <1490864181-2192-1-git-send-email-richard@nod.at> <4c7a176b-6132-7936-a04f-d4def5e56320@nod.at> Cc: linux-kernel@vger.kernel.org, dedekind1@gmail.com, stable@vger.kernel.org, Ralph Sennhauser , Amir Goldstein From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <646ae733-5037-3072-7151-b055a8fa1521@intel.com> Date: Thu, 30 Mar 2017 14:57:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <4c7a176b-6132-7936-a04f-d4def5e56320@nod.at> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1345 Lines: 31 On 30/03/17 13:23, Richard Weinberger wrote: > Am 30.03.2017 um 11:49 schrieb Richard Weinberger: >> Am 30.03.2017 um 11:32 schrieb Adrian Hunter: >>>> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c >>>> index 0858213a4e63..0139155045fe 100644 >>>> --- a/fs/ubifs/dir.c >>>> +++ b/fs/ubifs/dir.c >>>> @@ -748,6 +748,11 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir, >>>> goto out_fname; >>>> >>>> lock_2_inodes(dir, inode); >>>> + >>>> + /* Handle O_TMPFILE corner case, it is allowed to link a O_TMPFILE. */ >>>> + if (inode->i_nlink == 0) >>>> + ubifs_delete_orphan(c, inode->i_ino); >>> >>> Isn't there also a deletion inode in the journal? If the recovery sees that >>> won't it delete the file data? >> >> Yes, but ubifs_link() adds a new journal entry which revives the inode. >> This should cancel out the deletion, right? >> You know the UBIFS journal better than I do. :-) > > Reading deeper into the proved that I was wrong. > AFAIKT UBIFS' journal has currently no way to revive a deleted inode. > So, we have to think about a new solution. Deleting the orphan looks right. Just need to understand whether the recovery would do the right thing - actually it looks like O_TMPFILE might be OK and in other case we might be failing to remove nodes with sequence numbers greater than the deletion inode.