Re: [PATCH v4 0/5] ceph: fix spurious recover_session=clean errors

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

On Wed, Oct 7, 2020 at 8:17 PM Jeff Layton <jlayton@kernel.org> wrote:
>
> v4: test for CEPH_MOUNT_RECOVER in more places
> v3: add RECOVER mount_state and allow dumping pagecache when it's set
>     shrink size of mount_state field
> v2: fix handling of async requests in patch to queue requests
>
> This is the fourth revision of this patchset. The main difference from
> v3 is that this one converts more "==" tests for SHUTDOWN state into
> ">=", so that the RECOVER state is treated the same way.
>
> Original cover letter:
>
> Ilya noticed that he would get spurious EACCES errors on calls done just
> after blocklisting the client on mounts with recover_session=clean. The
> session would get marked as REJECTED and that caused in-flight calls to
> die with EACCES. This patchset seems to smooth over the problem, but I'm
> not fully convinced it's the right approach.
>
> The potential issue I see is that the client could take cap references to
> do a call on a session that has been blocklisted. We then queue the
> message and reestablish the session, but we may not have been granted
> the same caps by the MDS at that point.
>
> If this is a problem, then we probably need to rework it so that we
> return a distinct error code in this situation and have the upper layers
> issue a completely new mds request (with new cap refs, etc.)
>
> Obviously, that's a much more invasive approach though, so it would be
> nice to avoid that if this would suffice.
>
> Jeff Layton (5):
>   ceph: don't WARN when removing caps due to blocklisting
>   ceph: make fsc->mount_state an int
>   ceph: add new RECOVER mount_state when recovering session
>   ceph: remove timeout on allowing reconnect after blocklisting
>   ceph: queue MDS requests to REJECTED sessions when CLEANRECOVER is set
>

series
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>

>  fs/ceph/addr.c               |  4 ++--
>  fs/ceph/caps.c               |  4 ++--
>  fs/ceph/inode.c              |  2 +-
>  fs/ceph/mds_client.c         | 27 ++++++++++++++++-----------
>  fs/ceph/super.c              | 14 ++++++++++----
>  fs/ceph/super.h              |  3 +--
>  include/linux/ceph/libceph.h |  1 +
>  7 files changed, 33 insertions(+), 22 deletions(-)
>
> --
> 2.26.2
>