[PATCHES] Two patches for gpfs sharemodes

[Christof Schmitt]

On Thu, Aug 24, 2017 at 01:46:36PM +0200, Volker Lendecke wrote:
> On Wed, Aug 23, 2017 at 01:40:54PM -0700, Christof Schmitt via samba-technical wrote:
> > From 9474f1b1865636c7cc53a302b3225e3197f154c1 Mon Sep 17 00:00:00 2001
> > From: Christof Schmitt <cs at samba.org>
> > Date: Wed, 23 Aug 2017 10:33:42 -0700
> > Subject: [PATCH 1/2] vfs_gpfs: Do not map DELETE sharemode access to WRITE
> > 
> > A SMB client can deny the WRITE sharemode, but still grant the DELETE
> > sharemode. Mapping the requested DELETE access to WRITE access breaks
> > this case. Fix this by removing the incorrect mapping from DELETE access
> > to WRITE access.
> 
> Isn't the problem with GPFS_DENY_DELETE that it is mapped to a
> combination of other flags internally? The last time we discussed this
> GPFS_DENY_DELETE was not an independent bit in GPFS. This goes along
> with Ralph's question about the precise semantics. Can we get someone
> from the GPFS team to describe exactly what's going on internally?

The limitation of DENY_DELETE is that this bit can only be set together
with either DENY_READ, DENY_WRITE or both. So this does not cover all
possible cases (a SMB client allowing READ and WRITE access to others,
but preventing DELETE cannot be enforced through the current API).

On the other hand, we should leverage the current API as much as
possible and allow a SMB client to prevent others from deleting the file
when that can be enforced.

Christof