From: Damien Le Moal <Damien.LeMoal@wdc.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "dm-devel@redhat.com" <dm-devel@redhat.com>,
Mike Snitzer <snitzer@redhat.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Subject: Re: [PATCH v2 3/3] zonefs: fix synchronous write to sequential zone files
Date: Mon, 19 Apr 2021 07:08:46 +0000 [thread overview]
Message-ID: <BL0PR04MB651477B7ECC57FA61E1C99EFE7499@BL0PR04MB6514.namprd04.prod.outlook.com> (raw)
In-Reply-To: 20210419064529.GA19041@lst.de
On 2021/04/19 15:45, Christoph Hellwig wrote:
> On Sat, Apr 17, 2021 at 11:33:23AM +0900, Damien Le Moal wrote:
>> Synchronous writes to sequential zone files cannot use zone append
>> operations if the underlying zoned device queue limit
>> max_zone_append_sectors is 0, indicating that the device does not
>> support this operation. In this case, fall back to using regular write
>> operations.
>
> Zone append is a mandatory feature of the zoned device API.
Yes, I am well aware of that. All physical zoned devices and null blk do support
zone append, but the logical device created by dm-crypt is out. And we cannot
simply disable zone support in dm-crypt as there are use cases out there in the
field that I am aware of, in SMR space.
So this series is a compromise: preserve dm-crypt zone support for SMR (no one
uses the zone append emulation yet, as far as I know) by disabling zone append.
For zonefs, we can:
1) refuse to mount if ZA is disabled, same as btrfs
2) Do as I did in the patch, fallback to regular writes since that is easy to do
(zonefs file size tracks the WP position already).
I chose option (2) to allow for SMR+dm-crypt to still work with zonefs.
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2021-04-19 7:08 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-17 2:33 [PATCH v2 0/3] Fix dm-crypt zoned block device support Damien Le Moal
2021-04-17 2:33 ` [PATCH v2 1/3] dm: Introduce zone append support control Damien Le Moal
2021-04-17 2:33 ` [PATCH v2 2/3] dm crypt: Fix zoned block device support Damien Le Moal
2021-04-17 10:39 ` Johannes Thumshirn
2021-04-18 11:00 ` [dm-devel] " Milan Broz
2021-04-17 2:33 ` [PATCH v2 3/3] zonefs: fix synchronous write to sequential zone files Damien Le Moal
2021-04-19 6:45 ` Christoph Hellwig
2021-04-19 7:08 ` Damien Le Moal [this message]
2021-04-19 7:10 ` Christoph Hellwig
2021-04-20 1:20 ` Douglas Gilbert
2021-04-20 1:35 ` Damien Le Moal
2021-04-19 12:52 ` [dm-devel] [PATCH v2 0/3] Fix dm-crypt zoned block device support Mikulas Patocka
2021-04-19 13:02 ` Damien Le Moal
2021-04-19 13:55 ` Mikulas Patocka
2021-04-19 14:31 ` Milan Broz
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