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Date: Mon, 27 May 2024 14:22:26 +0200
From: Christian Brauner <brauner@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Aleksa Sarai <cyphar@cyphar.com>, 
	Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>, Chuck Lever <chuck.lever@oracle.com>, 
	Jeff Layton <jlayton@kernel.org>, Amir Goldstein <amir73il@gmail.com>, 
	Alexander Aring <alex.aring@gmail.com>, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org
Subject: Re: [PATCH RFC v2] fhandle: expose u64 mount id to
 name_to_handle_at(2)
Message-ID: <20240527-montag-beruhen-523b74214339@brauner>
References: <20240523-exportfs-u64-mount-id-v2-1-f9f959f17eb1@cyphar.com>
 <ZlMADupKkN0ITgG5@infradead.org>
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In-Reply-To: <ZlMADupKkN0ITgG5@infradead.org>

On Sun, May 26, 2024 at 02:25:34AM -0700, Christoph Hellwig wrote:
> On Thu, May 23, 2024 at 01:57:32PM -0700, Aleksa Sarai wrote:
> > Now that we provide a unique 64-bit mount ID interface in statx, we can
> > now provide a race-free way for name_to_handle_at(2) to provide a file
> > handle and corresponding mount without needing to worry about racing
> > with /proc/mountinfo parsing.
> 
> file handles are not tied to mounts, they are tied to super_blocks,
> and they can survive reboots or (less relevant) remounts.  This thus
> seems like a very confusing if not wrong interfaces.

I'm not fond of the interface as I've said on an earlier version, but
name_to_handle_at() has always exposed the mount id. IOW, this isn't
adding a new concept to the system call.