Re: [RFC PATCH 4/4] ceph: queue request when CLEANRECOVER is set

["Yan, Zheng" <ukernel@gmail.com>]

On Fri, Sep 25, 2020 at 10:08 PM Jeff Layton <jlayton@kernel.org> wrote:
>
> Ilya noticed that the first access to a blacklisted mount would often
> get back -EACCES, but then subsequent calls would be OK. The problem is
> in __do_request. If the session is marked as REJECTED, a hard error is
> returned instead of waiting for a new session to come into being.
>
> When the session is REJECTED and the mount was done with
> recover_session=clean, queue the request to the waiting_for_map queue,
> which will be awoken after tearing down the old session.
>
> URL: https://tracker.ceph.com/issues/47385
> Reported-by: Ilya Dryomov <idryomov@gmail.com>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/ceph/mds_client.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index fd16db6ecb0a..b07e7adf146f 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -2819,7 +2819,10 @@ static void __do_request(struct ceph_mds_client *mdsc,
>         if (session->s_state != CEPH_MDS_SESSION_OPEN &&
>             session->s_state != CEPH_MDS_SESSION_HUNG) {
>                 if (session->s_state == CEPH_MDS_SESSION_REJECTED) {
> -                       err = -EACCES;
> +                       if (ceph_test_mount_opt(mdsc->fsc, CLEANRECOVER))
> +                               list_add(&req->r_wait, &mdsc->waiting_for_map);
> +                       else
> +                               err = -EACCES;

During recovering session, client drops all dirty caps and abort all
osd requests.  It does not make sense , some operations are waiting,
the others get aborted.

>                         goto out_session;
>                 }
>                 /*
> --
> 2.26.2
>