[v2,2/2] ceph: update the oldest_client_tid via the renew caps

From: Xiubo Li <xiubli@redhat.com>

Update the oldest_client_tid via the session renew caps msg to
make sure that the MDSs won't pile up the completed request list
in a very large size.

URL: https://tracker.ceph.com/issues/63364
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/mds_client.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

On Fri, Nov 17, 2023 at 1:47 PM <xiubli@redhat.com> wrote:
>
> From: Xiubo Li <xiubli@redhat.com>
>
> Update the oldest_client_tid via the session renew caps msg to
> make sure that the MDSs won't pile up the completed request list
> in a very large size.
>
> URL: https://tracker.ceph.com/issues/63364
> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> ---
>  fs/ceph/mds_client.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index fdfea11d9568..7bdee08ec2eb 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -1579,6 +1579,9 @@ create_session_full_msg(struct ceph_mds_client *mdsc, int op, u64 seq)
>                 size = METRIC_BYTES(count);
>         extra_bytes += 2 + 4 + 4 + size;
>
> +       /* flags, mds auth caps and oldest_client_tid */
> +       extra_bytes += 4 + 4 + 8;
> +
>         /* Allocate the message */
>         msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + extra_bytes,
>                            GFP_NOFS, false);
> @@ -1597,9 +1600,9 @@ create_session_full_msg(struct ceph_mds_client *mdsc, int op, u64 seq)
>          * Serialize client metadata into waiting buffer space, using
>          * the format that userspace expects for map<string, string>
>          *
> -        * ClientSession messages with metadata are v4
> +        * ClientSession messages with metadata are v7
>          */
> -       msg->hdr.version = cpu_to_le16(4);
> +       msg->hdr.version = cpu_to_le16(7);
>         msg->hdr.compat_version = cpu_to_le16(1);
>
>         /* The write pointer, following the session_head structure */
> @@ -1635,6 +1638,15 @@ create_session_full_msg(struct ceph_mds_client *mdsc, int op, u64 seq)
>                 return ERR_PTR(ret);
>         }
>
> +       /* version == 5, flags */
> +       ceph_encode_32(&p, 0);
> +
> +       /* version == 6, mds auth caps */
> +       ceph_encode_32(&p, 0);
> +
> +       /* version == 7, oldest_client_tid */
> +       ceph_encode_64(&p, mdsc->oldest_tid);
> +
>         msg->front.iov_len = p - msg->front.iov_base;
>         msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
>
> @@ -2030,10 +2042,12 @@ static int send_renew_caps(struct ceph_mds_client *mdsc,
>
>         doutc(cl, "to mds%d (%s)\n", session->s_mds,
>               ceph_mds_state_name(state));
> -       msg = ceph_create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
> +
> +       /* send connect message */
> +       msg = create_session_full_msg(mdsc, CEPH_SESSION_REQUEST_RENEWCAPS,
>                                       ++session->s_renew_seq);
> -       if (!msg)
> -               return -ENOMEM;
> +       if (IS_ERR(msg))
> +               return PTR_ERR(msg);
>         ceph_con_send(&session->s_con, msg);
>         return 0;
>  }
> --
> 2.41.0
>

Reviewed-by: Venky Shankar <vshankar@redhat.com>
Tested-by: Venky Shankar <vshankar@redhat.com>