Re: [PATCH v2] ceph: fix deadlock bugs by making iput() calls asynchronous

[Max Kellermann]

On Wed, Sep 17, 2025 at 10:25 PM Max Kellermann
<max.kellermann@xxxxxxxxx> wrote:
>
> On Wed, Sep 17, 2025 at 10:20 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Wed, Sep 17, 2025 at 03:59:07PM +0200, Max Kellermann wrote:
> >
> > > After advice from Mateusz Guzik, I decided to do the latter.  The
> > > implementation is simple because it piggybacks on the existing
> > > work_struct for ceph_queue_inode_work() - ceph_inode_work() calls
> > > iput() at the end which means we can donate the last reference to it.
> > >
> > > This patch adds ceph_iput_async() and converts lots of iput() calls to
> > > it - at least those that may come through writeback and the messenger.
> >
> > What would force those delayed calls through at fs shutdown time?
>
> I was wondering the same a few days ago, but found no code to enforce
> wait for work completion during shutdown

What about flush_fs_workqueues() in fs/ceph/super.c? Is this what
you're looking for, Al?