2014-09-03 09:14:13

by Cedric Blancher

[permalink] [raw]
Subject: Accessing alternate data streams on NFSv4 server?

is there any utility which can be used to access alternate data
streams (which can be accessed on Solaris via O_XATTR or newer
bash/ksh versions via cd -@) on Linux?

Ced
--
Cedric Blancher <[email protected]>
Institute Pasteur


2014-09-03 12:22:22

by Trond Myklebust

[permalink] [raw]
Subject: Re: Accessing alternate data streams on NFSv4 server?

On Wed, Sep 3, 2014 at 5:14 AM, Cedric Blancher
<[email protected]> wrote:
> is there any utility which can be used to access alternate data
> streams (which can be accessed on Solaris via O_XATTR or newer
> bash/ksh versions via cd -@) on Linux?
>
> Ced

No.

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> Cedric Blancher <[email protected]>
> Institute Pasteur
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Trond Myklebust

Linux NFS client maintainer, PrimaryData

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2014-09-03 12:57:23

by Trond Myklebust

[permalink] [raw]
Subject: Re: Accessing alternate data streams on NFSv4 server?

On Wed, Sep 3, 2014 at 8:43 AM, Cedric Blancher
<[email protected]> wrote:
> On 3 September 2014 14:22, Trond Myklebust
> <[email protected]> wrote:
>> On Wed, Sep 3, 2014 at 5:14 AM, Cedric Blancher
>> <[email protected]> wrote:
>>> is there any utility which can be used to access alternate data
>>> streams (which can be accessed on Solaris via O_XATTR or newer
>>> bash/ksh versions via cd -@) on Linux?
>>>
>>> Ced
>>
>> No.
>
> What can we do to access such data - except porting all stuff to
> Windows or stick with Solaris/AIX?

You have asked this question before. There is nothing new to add to
the previous mailing threads.

There is no support for Solaris style subfiles on any Linux
filesystem, including NFS. I'm not aware of anyone having any plans to
add such support after Reiser4 died. There is no indication that POSIX
is anywhere near ready to accept O_XATTR or any other interfaces to
support subfiles.

--
Trond Myklebust

Linux NFS client maintainer, PrimaryData

[email protected]

2014-09-03 12:43:45

by Cedric Blancher

[permalink] [raw]
Subject: Re: Accessing alternate data streams on NFSv4 server?

On 3 September 2014 14:22, Trond Myklebust
<[email protected]> wrote:
> On Wed, Sep 3, 2014 at 5:14 AM, Cedric Blancher
> <[email protected]> wrote:
>> is there any utility which can be used to access alternate data
>> streams (which can be accessed on Solaris via O_XATTR or newer
>> bash/ksh versions via cd -@) on Linux?
>>
>> Ced
>
> No.

What can we do to access such data - except porting all stuff to
Windows or stick with Solaris/AIX?

Ced
--
Cedric Blancher <[email protected]>
Institute Pasteur

2014-09-03 13:31:23

by Emmanuel Florac

[permalink] [raw]
Subject: Re: Accessing alternate data streams on NFSv4 server?

Le Wed, 3 Sep 2014 11:14:13 +0200
Cedric Blancher <[email protected]> ?crivait:

> is there any utility which can be used to access alternate data
> streams (which can be accessed on Solaris via O_XATTR or newer
> bash/ksh versions via cd -@) on Linux?
>

Extended attributes work fine on various Linux filesystems, and are
accessible through samba and NFS. However AFAIK only Solaris supports
full alternate data streams (bigger than 64K). BTW from a quick google
search it looks like you're about the only one in the world using this
very idiosyncratic feature ;) -- all other references to this problem
comes from you on FreeBSD lists :)

I guess it would be too much work to implement in either Linux or
FreeBSD as the VFS doesn't really provide anything to support that
properly.

So your best bet is to check with preferably SmartOS, or
eventually OmniOS/IllumOS (all of them OpenSolaris forks);

or to write a samba module as a horrid hack to emulate the API and
store the big XATTRs into alternate files /alla/ .AppleDouble
(.SolarisDouble anyone?). I know, I know; it's ugly as sin but it seems
actually quite doable, if not actually easy.

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