[lustre-devel] [PATCH 6/8] lustre: fld: fld client lookup should retry

[Andreas Dilger]

This is definitely client code. 

Cheers, Andreas

> On Jul 24, 2019, at 19:44, James Simmons <jsimmons at infradead.org> wrote:
> 
> From: wang di <di.wang at intel.com>
> 
> If FLD client lookup fails because of the remote target
> is shutdown (or deactive), it should retry another target,
> otherwise it will cause the application failure.
> 
> And FLD client should stop retry if the import has
> been deactive.
> 
> WC-bug-id: https://jira.whamcloud.com/browse/LU-6419
> Lustre-commit: 3ededde903c92f8485cae0dc9f958f194ff0b140
> Signed-off-by: wang di <di.wang at intel.com>
> Reviewed-on: http://review.whamcloud.com/14313
> Reviewed-by: Lai Siyao <lai.siyao at intel.com>
> Reviewed-by: Fan Yong <fan.yong at intel.com>
> Reviewed-by: Alex Zhuravlev <alexey.zhuravlev at intel.com>
> Reviewed-by: Oleg Drokin <oleg.drokin at intel.com>
> ---
> fs/lustre/fld/fld_request.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/lustre/fld/fld_request.c b/fs/lustre/fld/fld_request.c
> index 60e7105..dfd4ae9 100644
> --- a/fs/lustre/fld/fld_request.c
> +++ b/fs/lustre/fld/fld_request.c
> @@ -367,7 +367,7 @@ int fld_client_rpc(struct obd_export *exp,
>    rc = ptlrpc_queue_wait(req);
>    obd_put_request_slot(&exp->exp_obd->u.cli);
>    if (rc != 0) {
> -        if (imp->imp_state != LUSTRE_IMP_CLOSED) {
> +        if (imp->imp_state != LUSTRE_IMP_CLOSED && !imp->imp_deactive) {
>            /* Since LWP is not replayable, so it will keep
>             * trying unless umount happens, otherwise it would
>             * cause unecessary failure of the application.
> @@ -404,6 +404,7 @@ int fld_client_lookup(struct lu_client_fld *fld, u64 seq, u32 *mds,
> {
>    struct lu_seq_range res = { 0 };
>    struct lu_fld_target *target;
> +    struct lu_fld_target *origin;
>    int rc;
> 
>    rc = fld_cache_lookup(fld->lcf_cache, seq, &res);
> @@ -415,7 +416,8 @@ int fld_client_lookup(struct lu_client_fld *fld, u64 seq, u32 *mds,
>    /* Can not find it in the cache */
>    target = fld_client_get_target(fld, seq);
>    LASSERT(target);
> -
> +    origin = target;
> +again:
>    CDEBUG(D_INFO,
>           "%s: Lookup fld entry (seq: %#llx) on target %s (idx %llu)\n",
>           fld->lcf_name, seq, fld_target_name(target), target->ft_idx);
> @@ -424,6 +426,23 @@ int fld_client_lookup(struct lu_client_fld *fld, u64 seq, u32 *mds,
>    fld_range_set_type(&res, flags);
>    rc = fld_client_rpc(target->ft_exp, &res, FLD_QUERY, NULL);
> 
> +    if (rc == -ESHUTDOWN) {
> +        /* If fld lookup failed because the target has been shutdown,
> +         * then try next target in the list, until trying all targets
> +         * or fld lookup succeeds
> +         */
> +        spin_lock(&fld->lcf_lock);
> +        if (target->ft_chain.next == fld->lcf_targets.prev)
> +            target = list_entry(fld->lcf_targets.next,
> +                        struct lu_fld_target, ft_chain);
> +        else
> +            target = list_entry(target->ft_chain.next,
> +                         struct lu_fld_target,
> +                         ft_chain);
> +        spin_unlock(&fld->lcf_lock);
> +        if (target != origin)
> +            goto again;
> +    }
>    if (rc == 0) {
>        *mds = res.lsr_index;
> 
> -- 
> 1.8.3.1
>