Comment 20 for bug 1873074

Right, I think see your point. Even though it's an ordinary filesystem
as a callee of VFS, it is not as a caller (since most filesystems don't
do that), and in this role, it might have to do non-ordinary things too.

Thanks for clarifying that re-open is not an option. I imagined these
attributes were kept at the aufs file, and that the underlying fs file
was not that related. (as I mentioned, I'm not an aufs expert, nor fs
expert, for that matter.)

In general, i_readcount_inc/dec() outside of VFS is likely not the
"right" thing to do, but this particular case is far from "general"
(given the operation: to change an entire branch/layer RW->RO; and
being an union/layer filesystem; and while files are still open.)

... so I guess there is the "doable" thing to do, right? :)

Thanks for the patch!