Re: [GIT PULL] Ceph updates for 5.20-rc1

[Al Viro <viro@zeniv.linux.org.uk>]

On Thu, Aug 11, 2022 at 05:08:11PM -0400, Jeff Layton wrote:

> Actually, I never got a formal ack from Al. I did send it repeatedly,
> but I assume he has been too busy to respond. We've had it sitting in
> linux-next for a couple of months, and he did suggest that approach in
> the first place, but I too would also prefer to see his official ack on
> it.

"Suggested approach" had been about inode_insert5() changes, right?
But that's fs/inode.c side of things...  I have to admit that I'd missed
the unlining d_same_name() - exporting the sucker per se didn't look
insane and I hadn't looked at that in details ;-/

Looking at it now...  might be worth renaming it into __d_same_name(),
leaving it inlined and exporting a wrapper; not sure if the impact on
d_lookup()/__d_lookup()/d_alloc_parallel() is worth worrying about it,
though.

Profiling a case when we have a plenty of files in the same directory
on tmpfs, with something earlier in the pathname to kick out of RCU
mode (e.g. going through /proc/self/cwd) might be interesting...