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From: "Javier González" <javier@javigon.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Christoph Hellwig" <hch@lst.de>,
	"Matias Bjørling" <mb@lightnvm.io>,
	linux-block@vger.kernel.org,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] : Switch to use new generic UUID API
Date: Thu, 24 Jan 2019 15:36:47 +0100	[thread overview]
Message-ID: <5FF168CC-9372-4DE5-BF62-DD3A2EE08384@javigon.com> (raw)
In-Reply-To: <CAHp75Vfd=B-AP=7KNFiDU-qER9BjB0Qw9Lyp+hb8x94NfQiZyA@mail.gmail.com>

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> On 24 Jan 2019, at 15.13, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> 
> On Thu, Jan 24, 2019 at 3:45 PM Javier González <javier@javigon.com> wrote:
>>> On 24 Jan 2019, at 14.36, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
>>> On Thu, Jan 24, 2019 at 3:19 PM Javier González <javier@javigon.com> wrote:
>>>>> On 24 Jan 2019, at 13.16, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> 
>>>>> header.uuid is defined using __u8 type, I'm not sure we can use guid_t there.
>>>> 
>>>> We can turn it into a guid_t and bump the minor version.
>>> 
>>> It's not so easy. __uXX types are dedicated for external APIs. guid_t
>>> is kernel internal type disregard of (still) presence some uapi bits.
>>> So, the question is those __uXX types in the driver definition is a
>>> simple mistake, (weird) style decision, or what?
>> 
>> I would define it as a mistake and I think it is worth fixing it. At the
>> moment we are only using this uuid for recovery purposes, to discard
>> data from a different pblk instance,
> 
> Does this come from outside of the kernel in any mean (user space,
> data from device, etc)?
> It sounds to me like it does. In this case there is no mistake and we
> may not use guid_t there.

pblk manages the metadata layout without involvement of the device or
user space, so no, no dependency at this moment.

It is not pushed anywhere yet, but I have been working on a tool to make
a pblk recovery tool to enable FTL repairs if something fails in the
kernel recovery path. Here, I use this uuid to identify the
instance - is there a way to reconcile guid_t with user space, which
currently uses the __u8?

Javier

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  reply	other threads:[~2019-01-24 14:36 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-10 14:30 [PATCH v1] : Switch to use new generic UUID API Andy Shevchenko
2019-01-21  8:47 ` Christoph Hellwig
2019-01-24 12:16   ` Andy Shevchenko
2019-01-24 13:17     ` Javier González
2019-01-24 13:36       ` Andy Shevchenko
2019-01-24 13:45         ` Javier González
2019-01-24 14:13           ` Andy Shevchenko
2019-01-24 14:36             ` Javier González [this message]
2019-01-24 16:38               ` Andy Shevchenko
2019-01-24 16:41                 ` Javier González

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