Re: [nfsv4] Last call for NSDB Protocol for Federated Filesystems (Oct 4 - Oct 22nd)

[Chuck Lever <[e-mail]>]

On Oct 22, 2010, at 1:31 PM, James Lentini wrote:

> 
> 
> On Mon, 4 Oct 2010, Spencer Shepler wrote:
> 
>> 
>> Last call for the following document starts today and ends on October 22nd
>> 
>> NSDB Protocol for Federated Filesystems
>> draft-ietf-nfsv4-federated-fs-protocol-09
>> 
>> Comments on the document, other than the editorial, should be
>> directed to the NFSv4 WG alias.   Document links are as follows:
>> 
>> html: http://tools.ietf.org/html/draft-ietf-nfsv4-federated-fs-protocol-09
>> txt: http://tools.ietf.org/id/draft-ietf-nfsv4-federated-fs-protocol-09.txt
> 
> There has been some discussion regarding the fedfsAnnotation LDAP 
> attribute defined in Section 4.2.1.12 that I wanted to record as part 
> of this thread.
> 
> Chuck Lever discovered some ambiguities in the description of this 
> attribute's format. We discussed those issues during the FedFS concall 
> on 10/14. A revised description that attempts to eliminate those 
> ambiguities is included below.
> 
> In the process of reviewing the revised text, Chuck, my co-authors, 
> and I have have been considering the utility of including this 
> annotation mechanism. Before LDAP was chosen for the NSDB protocol, 
> this attribute was created to allow private schema extensions. Given 
> our use of LDAP, this attribute may be obsolete.
> 
> Using LDAP there are other, arguably more natural, ways to allow for 
> schema extensions. For example, LDAP allows an entry's schema 
> definition to be extended by adding additional object types to the 
> entry. In this approach, the KEYs and VALUEs defined in Section 
> 4.2.1.12 map to LDAP attribute types and values respectively. This 
> approach would allow implementers to define their own annotation 
> attributes, and would allow for standardizing such attributes if there 
> was interest.
> 
> Are there objections to removing the fedfsAnnotation attribute from 
> the schema and recommending that schema extensions be handled as 
> described above?
> 
> -james
> 
> Revised text for Section 4.2.1.12 
> (if fedfsAnnotation is retained):
> ------------------------------------------
> 
> 4.2.1.12. fedfsAnnotation
> 
> 
>   A fedfsAnnotation contains an object annotation formatted as a 
>   key/value pair.
> 
>   This attribute is multi-valued; an object type that permits
>   annotations may have any number of annotations per instance.
> 
>   A fedfsAnnotation attribute is a human-readable UTF-8 string.
>   The value MUST NOT contain a non-terminal NUL character and

Rob pointed out to me that UTF-8 strings by definition may not have a non-terminal NUL character, so the above MUST NOT text is not necessary.

>   MUST be formatted according to the following ABNF [RFC 5234] rules:
> 
>   ANNOTATION = KEY EQUALS VALUE
>   KEY        = ITEM
>   VALUE      = ITEM
>   ITEM       = BLANK DQUOTE STR DQUOTE BLANK
>   BLANK      = 0*EMPTY
>   EMPTY      = SPACE / HTAB
>   HTAB       = %x09 ; horizontal tab
>   STR        = 0*UTF8
> 
>   The DQUOTE, EQUALS, UTF8, and SPACE rules are defined in [RFC4512].
> 
>   The following escape sequences are allowed:
> 
>                     +-----------------+-------------+
>                     | escape sequence | replacement |
>                     +-----------------+-------------+
>                     |        \\       |      \      |
>                     |        \"       |      "      |
>                     +-----------------+-------------+
> 
>   A fedfsAnnotation value SHOULD be processed as follows:
> 
>   1. Scan through the attribute value and replace the above escape 
>      sequences.
>   2. Parse the results of the previous step according to the 
>      ANNOTATION rule.
> 
>   A fedfsAnnotation attribute that does not adhere to this format
>   SHOULD be ignored.
> 
>   The following are examples of valid fedfsAnnotation attributes:
> 
>            "key1" = "foo"
>            "another key"=    "x=3"
>            "key-2" = "A string with \" and \\ characters."
>            "key_3" = "Backslash before final quote: \\" 
> 
>   which correspond to the following key/value pairs:
> 
>            +-------------+-----------------------------------+
>            |     key     |               value               |
>            +-------------+-----------------------------------+
>            |     key1    |                foo                |
>            | another key |                x=3                |
>            |    key-2    | A string with " and \ characters. |
>            |    key_3    | Backslash before final quote: \   |
>            +-------------+-----------------------------------+
> 
>   <CODE BEGINS>
> 
>           ///
>           /// attributetype (
>           ///     1.3.6.1.4.1.31103.1.12 NAME 'fedfsAnnotation'
>           ///     DESC 'Annotation of an object'
>           ///     SUP name
>           ///     )
>           ///
> 
>   <CODE ENDS>
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-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com