From: Hannes Reinecke <hare@suse.de>
To: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
Jens Axboe <axboe@fb.com>
Subject: Re: [PATCH 4/4] block: expose devt for GENHD_FL_HIDDEN disks
Date: Fri, 14 Dec 2018 10:44:09 +0100 [thread overview]
Message-ID: <97a032f0-5e10-2b9c-6f8d-d405e9f2cd2a@suse.de> (raw)
In-Reply-To: <20181214085606.GD5321@calabresa>
On 12/14/18 9:56 AM, Thadeu Lima de Souza Cascardo wrote:
> On Fri, Dec 14, 2018 at 08:47:20AM +0100, Hannes Reinecke wrote:
>> On 12/13/18 4:25 PM, Thadeu Lima de Souza Cascardo wrote:
>>> On Thu, Dec 13, 2018 at 03:32:18PM +0100, Christoph Hellwig wrote:
>>>> On Thu, Dec 13, 2018 at 10:18:40AM +0100, Hannes Reinecke wrote:
>>>>> Welll ... this is not just 'lsblk', but more importantly this will force
>>>>> udev to create _block_ device nodes for the hidden devices, essentially
>>>>> 'unhide' them.
>>>>>
>>>>> Is this what we want?
>>>>> Christoph?
>>>>> I thought the entire _point_ of having hidden devices is that the are ...
>>>>> well ... hidden ...
>>>>
>>>> Yes, that is why I really don't like the last two patches.
>>>>
>>>> And I've checked back - lsblk actually works just fine at the moment.
>>>> But it turns out once we create the slave links it stops working,
>>>> which is a really good argument against the first two patches, which
>>>> would otherwise seem nice..
>>>
>>> Which is why I have sent the "paths/" patchset in the first place. Because I
>>> did some homework and read the previous discussion about this, and how lsblk
>>> failure to behave with slave links led to the revert of the slaves/holders
>>> patch by Dr. Hannes.
>>>
>> But you haven't answered my question:
>>
>> Why can't we patch 'lsblk' to provide the required information even with the
>> current sysfs layout?
>>
>
> I think we could, but with my Ubuntu hat on, after the kernel fix for
> initramfs-tools, that is, slaves/holders links, the user will get an updated
> kernel that breaks the current lsblk on Bionic (Ubuntu 18.04). That will
> require that we backport the lsblk fix, which is not only more work, but there
> may be users who only update from -security, which is where kernel updates end
> regularly, but not this lsblk fix.
>
> And that kernel update is a regression against that old lsblk version.
>
Now you get me confused.
Which kernel update you are referring to?
We do _not_ provide any 'slave' link with the current upstream, so I
somewhat fail to see which breakage you are referring to ...
Confused,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
next prev parent reply other threads:[~2018-12-14 9:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 16:48 [PATCH 0/4] nvme multipath: expose slaves/holders Thadeu Lima de Souza Cascardo
2018-12-06 16:48 ` [PATCH 1/4] block: move holder tracking from struct block_device to hd_struct Thadeu Lima de Souza Cascardo
2018-12-13 9:14 ` Hannes Reinecke
2018-12-06 16:48 ` [PATCH 2/4] nvme: create slaves/holder entries for multipath devices Thadeu Lima de Souza Cascardo
2018-12-13 9:15 ` Hannes Reinecke
2018-12-06 16:48 ` [PATCH 3/4] nvme: Should not warn when a disk path is opened Thadeu Lima de Souza Cascardo
2018-12-13 9:16 ` Hannes Reinecke
2018-12-06 16:48 ` [PATCH 4/4] block: expose devt for GENHD_FL_HIDDEN disks Thadeu Lima de Souza Cascardo
2018-12-06 20:22 ` Christoph Hellwig
2018-12-12 8:32 ` Christoph Hellwig
2018-12-12 12:39 ` Thadeu Lima de Souza Cascardo
2018-12-13 9:18 ` Hannes Reinecke
2018-12-13 11:41 ` Thadeu Lima de Souza Cascardo
2018-12-13 12:19 ` Hannes Reinecke
2018-12-13 16:08 ` Thadeu Lima de Souza Cascardo
2018-12-13 14:32 ` Christoph Hellwig
2018-12-13 15:25 ` Thadeu Lima de Souza Cascardo
2018-12-13 20:20 ` Christoph Hellwig
2018-12-13 21:00 ` Thadeu Lima de Souza Cascardo
2018-12-14 7:47 ` Hannes Reinecke
2018-12-14 8:56 ` Thadeu Lima de Souza Cascardo
2018-12-14 9:06 ` Thadeu Lima de Souza Cascardo
2018-12-14 9:54 ` Hannes Reinecke
2018-12-14 10:18 ` Hannes Reinecke
2018-12-14 11:09 ` Thadeu Lima de Souza Cascardo
2018-12-14 9:44 ` Hannes Reinecke [this message]
2018-12-13 9:33 ` [PATCH 0/4] nvme multipath: expose slaves/holders Johannes Thumshirn
2018-12-13 11:35 ` Thadeu Lima de Souza Cascardo
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