Re: [RFC PATCH 2/4] ceph: don't mark mount as SHUTDOWN when recovering session

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2020-09-29 at 16:20 +0800, Yan, Zheng wrote:
> On Fri, Sep 25, 2020 at 10:08 PM Jeff Layton <jlayton@kernel.org> wrote:
> > When recovering a session (a'la recover_session=clean), we want to do
> > all of the operations that we do on a forced umount, but changing the
> > mount state to SHUTDOWN is wrong and can cause queued MDS requests to
> > fail when the session comes back.
> > 
> 
> code that cleanup page cache check the SHUTDOWN state.
> 

Ok, so we do need to do something else there if we don't mark the thing
SHUTDOWN. Maybe we ought to declare a new mount_state for
this...CEPH_MOUNT_RECOVERING ?

> > Only mark it as SHUTDOWN when umount_begin is called.
> > 
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> >  fs/ceph/super.c | 13 +++++++++----
> >  1 file changed, 9 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> > index 2516304379d3..46a0e4e1b177 100644
> > --- a/fs/ceph/super.c
> > +++ b/fs/ceph/super.c
> > @@ -832,6 +832,13 @@ static void destroy_caches(void)
> >         ceph_fscache_unregister();
> >  }
> > 
> > +static void __ceph_umount_begin(struct ceph_fs_client *fsc)
> > +{
> > +       ceph_osdc_abort_requests(&fsc->client->osdc, -EIO);
> > +       ceph_mdsc_force_umount(fsc->mdsc);
> > +       fsc->filp_gen++; // invalidate open files
> > +}
> > +
> >  /*
> >   * ceph_umount_begin - initiate forced umount.  Tear down the
> >   * mount, skipping steps that may hang while waiting for server(s).
> > @@ -844,9 +851,7 @@ static void ceph_umount_begin(struct super_block *sb)
> >         if (!fsc)
> >                 return;
> >         fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
> > -       ceph_osdc_abort_requests(&fsc->client->osdc, -EIO);
> > -       ceph_mdsc_force_umount(fsc->mdsc);
> > -       fsc->filp_gen++; // invalidate open files
> > +       __ceph_umount_begin(fsc);
> >  }
> > 
> >  static const struct super_operations ceph_super_ops = {
> > @@ -1235,7 +1240,7 @@ int ceph_force_reconnect(struct super_block *sb)
> >         struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
> >         int err = 0;
> > 
> > -       ceph_umount_begin(sb);
> > +       __ceph_umount_begin(fsc);
> > 
> >         /* Make sure all page caches get invalidated.
> >          * see remove_session_caps_cb() */
> > --
> > 2.26.2
> > 

-- 
Jeff Layton <jlayton@kernel.org>