On Sat, May 08, 2021 at 03:47:38PM -0700, Linus Torvalds wrote:

On Sat, May 8, 2021 at 3:42 PM Linus Torvalds
[off-list ref] wrote:

quoted

But your READ_ONCE() is definitely the right thing to do (whether we
do your re-org or not, and whether we do this "prepend_buffer" thing
or not).

Oh, and looking at it some more, I think it would probably be a good
thing to make __dentry_path() take a

       struct prepend_buffer *orig

argument, the same way prepend_path() does. Also, like prepend_path(),
the terminating NUL should probably be done by the caller.

Doing those two changes would simplify the hackery we now have in
"dentry_path()" due to the "//deleted" games. The whole "restore '/'
that was overwritten by the NUL added by __dentry_path() is
unbelievably ugly.

	Agreed.  Re READ_ONCE() - we are wrapped into
read_seqbegin_or_lock(&rename_lock, &seq) there, so it's more about
being explicit than about correctness considerations.