From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-x532.google.com ([2a00:1450:4864:20::532]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1g1dO2-0000hx-J5 for linux-mtd@lists.infradead.org; Sun, 16 Sep 2018 20:11:20 +0000 Received: by mail-ed1-x532.google.com with SMTP id k14-v6so11206303edr.13 for ; Sun, 16 Sep 2018 13:11:08 -0700 (PDT) Subject: Re: UBIFS issues within kernel 4.14.69? To: Richard Weinberger Cc: OpenWrt Development List , linux-mtd@lists.infradead.org References: <18519120.7jNkZpEG5c@blindfold> <1680286.R2LEE90rvs@blindfold> From: Koen Vandeputte Message-ID: <14d0c8dc-111d-57e1-e86b-ca28544933b3@ncentric.com> Date: Sun, 16 Sep 2018 22:11:07 +0200 MIME-Version: 1.0 In-Reply-To: <1680286.R2LEE90rvs@blindfold> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 16-09-18 21:39, Richard Weinberger wrote: > Koen, > > Am Samstag, 15. September 2018, 09:13:09 CEST schrieb Richard Weinberger: >> Koen, >> >> Am Dienstag, 11. September 2018, 16:26:34 CEST schrieb Koen Vandeputte: >>> On 2018-09-11 15:46, Koen Vandeputte wrote: >>>> Hi Richard, >>> ... >>> >>>> I'm only seeing these issues on UBIFS enabled volumes. >>>> >>>> It seems it's related to one of your 5 commits, but I'm still in the >>>> process of bisecting to find the actual culprit. >>>> As soon as I've found it, I'll let you know, but maybe you already >>>> have an idea here? >>>> >>> Reverting ("ubifs: xattr: Don't operate on deleted inodes") fixes the >>> weird issues. >> Thanks for finding that bad commit! >> I fear by fixing one bug I've uncovered another one. >> >> So, I guess you are using overlayfs? >> Which overlayfs features are you using? > I guess I've figured myself. > overlayfs is using temp files (O_TMPFILE), and a recent overlayfs > feature uses xattrs to indicate directory redirects. > So it can happen that a temp file, which has link count 0, gains > xattrs. > > UBIFS models xattrs like regular files in directories. Since you cannot > add new files to a unlinked directory, UBIFS kind of enforced that for > xattrs too. > I say "kind of" because technically it works but can trigger an assertion > in UBIFS's journal code. > Recently I saw this assertion but failed to conclude that xattr operations on > unlinked files are perfectly fine and "fixed" the assert. > > The right solution is reverting "ubifs: xattr: Don't operate on deleted inodes" > and removing the false positive asserts from UBIFS' journal code. > > Sadly xfstests does not test for that, I'll prepare a new test case. > Maybe other file systems got this wrong too. > > Thanks, > //richard > Hi Richard, Apologies for the late reply. It was a busy weekend with the kids .. I'm very pleased to read you already have a good idea of what is going on here. Can I conclude you will provide a patch upstream to revert this specific commit? Please keep me in CC in case you do, so I can backport it properly into OpenWrt on the next kernel bump. (until it is present in a future stable) Once again, I highly appreciate you fast response in trying to get this fixed. Thank you Richard, Koen Reported-by: Koen Vandeputte