Re: [PATCH 1/4] xfs: hide private inodes from bulkstat and handle functions

From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 1/4] xfs: hide private inodes from bulkstat and handle functions
Date: Wed, 28 Feb 2024 09:02:30 -0800	[thread overview]
Message-ID: <Zd9nJj3Lw4kUYIY6@infradead.org> (raw)
In-Reply-To: <20240228165227.GH1927156@frogsfrogsfrogs>

On Wed, Feb 28, 2024 at 08:52:27AM -0800, Darrick J. Wong wrote:
> that are private to XFS.  What this means is that userspace should never
> be able to access any information about these files, and should not be
> able to open these files by handle.
> 
> "Callers must not be allowed to link these files into the directory
> tree, which should suffice to keep these private inodes actually
> private.  I_LINKABLE is therefore left unset.

I_LINKABLE is only set for O_TMPFILE, so I wouldn't even bother with
that.  But thinking about this:  what i_nlink do these private inodes
have?  If it is >= 1, we probably want to add an IS_PRIVATE check
to xfs_link just in case they ever leak out to a place where ->link
could be called.