linux-kernel - Re: [PATCH 8/8] cifs: Rename posix to nfs in parse_reparse_posix() and reparse_posix

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Message-ID: <5431fa20-089d-4d4e-ba9f-926860d4f202@samba.org>
Date: Sun, 29 Sep 2024 14:52:29 +0200
From: Ralph Boehme <slow@...ba.org>
To: Pali Rohár <pali@...nel.org>
Cc: Steve French <smfrench@...il.com>, Steve French <sfrench@...ba.org>,
 Paulo Alcantara <pc@...guebit.com>,
 Ronnie Sahlberg <ronniesahlberg@...il.com>, linux-cifs@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 8/8] cifs: Rename posix to nfs in parse_reparse_posix()
 and reparse_posix_data

On 9/29/24 11:26 AM, Pali Rohár wrote:
> Hello Ralph, thank you for information. So in case Samba is not
> going to use IO_REPARSE_TAG_NFS as primary way to serve special
> files, then it still makes sense to do this structure rename with my
> patch?

that's up to Paulo and Steve. I can only talk protocol/spec and server. :)

> Anyway, Windows clients mostly do not use IO_REPARSE_TAG_NFS.

They don't *create* it, but they can *read* and present it. But I guess 
that's what you meant.

> From my knowledge on Windows this tag is used only by Windows NFS
> server. So scenario when Windows sends IO_REPARSE_TAG_NFS over SMB
> would be rare... It would be needed to export NFS share via Windows
> NFS server from SMB mount connected to Samba server.

That's out of scope as far as SMB3 POSIX Extensions and I are concerned. :)

> Note that Windows NFS client stores data about special files in EAs.
> So for example if you mount export from Linux NFS server by Windows
> NFS client, then NFS symlink would be visible to Windows
> applications as regular file with "NfsSymlinkTargetName" EA. More
> info is in this email: https://marc.info/?l=samba-
> technical&m=121423255119680
> 
> And this is what are Windows applications using if they want to
> access data of special files. So application access
> "NfsSymlinkTargetName" EA and not IO_REPARSE_TAG_NFS reparse tag.

For symlinks SMB3 POSIX Extensions will use what Windows uses natively: 
IO_REPARSE_TAG_SYMLINK.

> To my knowledge neither Samba, nor Linux CIFS client supports 
> "NfsSymlinkTargetName" EA for creating or parsing symlink.

for Samba: yup.

-slow

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