linux-kernel - Re: [dm-devel] [PATCH v4 00/13] support non power of 2 zoned devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <PH0PR04MB741634259FDCF264BF1CA7259BD39@PH0PR04MB7416.namprd04.prod.outlook.com>
Date:   Fri, 20 May 2022 09:30:43 +0000
From:   Johannes Thumshirn <Johannes.Thumshirn@....com>
To:     Javier González <javier.gonz@...sung.com>,
        Hannes Reinecke <hare@...e.de>
CC:     Damien Le Moal <damien.lemoal@...nsource.wdc.com>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Theodore Ts'o <tytso@....edu>, Christoph Hellwig <hch@....de>,
        Pankaj Raghav <p.raghav@...sung.com>,
        "axboe@...nel.dk" <axboe@...nel.dk>,
        "pankydev8@...il.com" <pankydev8@...il.com>,
        "gost.dev@...sung.com" <gost.dev@...sung.com>,
        "jiangbo.365@...edance.com" <jiangbo.365@...edance.com>,
        "linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "dm-devel@...hat.com" <dm-devel@...hat.com>,
        "dsterba@...e.com" <dsterba@...e.com>,
        "linux-btrfs@...r.kernel.org" <linux-btrfs@...r.kernel.org>,
        Jaegeuk Kim <jaegeuk@...nel.org>
Subject: Re: [dm-devel] [PATCH v4 00/13] support non power of 2 zoned devices

On 20/05/2022 08:27, Javier González wrote:
> So you are suggesting adding support for !PO2 in the block layer and
> then a dm to present the device as a PO2 to the FS? This at least
> addresses the hole issue for raw zoned block devices, so it can be a
> first step.
> 
> This said, it seems to me that the changes to the FS are not being a
> real issue. In fact, we are exposing some bugs while we generalize the
> zone size support.
> 
> Could you point out what the challenges in btrfs are in the current
> patches, that it makes sense to add an extra dm layer?

I personally don't like the padding we need to do for the super block.

As I've pointed out to Pankaj already, I don't think it is 100% powerfail
safe as of now. It could probably be made, but that would also involve
changing non-zoned btrfs code which we try to avoid as much as we can.

As Damien already said, we still have issues with the general zoned 
support in btrfs, just have a look at the list of open issues [1] we
have. 

[1] https://github.com/naota/linux/issues/