Re: [PATCH RFC v2] fhandle: expose u64 mount id to name_to_handle_at(2)

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:

quoted

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.