Re: [PATCH v2] fuse: permit freezing while waiting for request answer

[Miklos Szeredi]

On Thu, 20 Aug 2026 at 12:41, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> Also, you'd be putting suspend success in the hands of userspace, that
> sounds like a mighty fail right there.

Freeze ordering is also a hard/impossible problem without the help of
userspace.  One obvious heuristic is if task has a /dev/fuse fd open,
it is a server.  This simple ordering between server and non-server
tasks fails if

 - task X is a server of A, while also doing ops on B

 - task X is server, blocked on task Y which is not a server

What about adding a flag to mutex/rwsem that allows making them
freezable at setup time?  Then fuse fs could set that flag for its
locks (including VFS locks).

Thanks,
Miklos