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From: Bob Liu <bob.liu@oracle.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: jgross@suse.com, Ian.Jackson@citrix.com, Paul.Durrant@citrix.com,
	roger.pau@citrix.com, xen-devel@lists.xen.org
Subject: Re: [RFC PATCH v2] Data integrity extension(DIX) support for xen-block
Date: Wed, 20 Apr 2016 20:08:30 +0800	[thread overview]
Message-ID: <5717713E.2020703@oracle.com> (raw)
In-Reply-To: <571744D4.7080406@citrix.com>


On 04/20/2016 04:59 PM, David Vrabel wrote:
> On 20/04/16 08:26, Bob Liu wrote:
>>
>>  /*
>> + * Recognized only if "feature-data-integrity" is present in backend xenbus info.
>> + * A request with BLKIF_OP_DIX_FLAG indicates the following request is a special
>> + * request which only contains integrity-metadata segments of current request.
>> + *
>> + * If a backend does not recognize BLKIF_OP_DIX_FLAG, it should *not* create the
>> + * "feature-data-integrity" node!
>> + */
>> +#define BLKIF_OP_DIX_FLAG (0x80)
> 
> This looks fine as a mechanism for actually transferring the data but
> you do need to specify:
> 
> 1. The format of this DIX data.  You may reference external
> specifications for this.
> 

Sure!

> 2. A mechanism for reporting which DIX formats the backend supports and
> a way for the frontend to select one (if multiple are selected).
> 

The "feature-data-integrity" could be extended to "unsigned int" instead of "bool",
so as to report all DIX formats backend supports.

> 3. The behaviour the frontend can expect from the backend.  (e.g., if
> the frontend writes sector S with DIX data D, a read of sector S with
> complete with DIX data D).
> 

Sorry, I didn't get the point of this example.

Thank you for your review!

-- 
Regards,
-Bob

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  reply	other threads:[~2016-04-20 12:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-20  7:26 [RFC PATCH v2] Data integrity extension(DIX) support for xen-block Bob Liu
2016-04-20  8:59 ` David Vrabel
2016-04-20 12:08   ` Bob Liu [this message]
2016-04-20 13:49     ` David Vrabel

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