2021년 10월 6일 (수) 오전 11:06, Namjae Jeon <linkinjeon@xxxxxxxxxx>님이 작성:
>
> [snip]
> >
> > - if (credits_requested > 0) {
> > + /* We must grant 0 credit for the final response of an asynchronous
> > + * operation.
> > + */
> > + if ((hdr->Flags & SMB2_FLAGS_ASYNC_COMMAND) && !work->multiRsp) {
> Can you elaborate what is this check ? especially this !work->multiRsp..
According to 3.3.4.2 Sending an Interim Response for an Asynchronous Operation
in MS-SMB2,
For the request that will be handled asynchronously, a server should send
an interim response, and grant credits to the interim response.
on the other hand, a server should grant 0 credit to the final response for the
request.
"hdr->Flags & SMB2_FLAGS_ASYNC" means that a response is an interim
or final, and "work->multiRsp == 0" means that a response is final. So in this
case, a server should grant 0 credit.
> > + credits_granted = 0;
> > + } else {
> > + /* according to smb2.credits smbtorture, Windows server
> > + * 2016 or later grant up to 8192 credits at one.
> > + */
> > aux_credits = credits_requested - 1;
> > - aux_max = 32;
> > if (hdr->Command == SMB2_NEGOTIATE)
> > aux_max = 0;
> > - aux_credits = (aux_credits < aux_max) ? aux_credits : aux_max;
> > - credits_granted = aux_credits + credit_charge;
> > + else
> > + aux_max = conn->max_credits - credit_charge;
> > + aux_credits = min_t(unsigned short, aux_credits, aux_max);
> > + credits_granted = credit_charge + aux_credits;
> > +
> > + if (conn->max_credits - conn->total_credits < credits_granted)
> > + credits_granted = conn->max_credits -
> > + conn->total_credits;
> >
> > - /* if credits granted per client is getting bigger than default
> > - * minimum credits then we should wrap it up within the limits.
> > - */
> > - if ((conn->total_credits + credits_granted) > min_credits)
> > - credits_granted = min_credits - conn->total_credits;
> > /*
> > * TODO: Need to adjuct CreditRequest value according to
> > * current cpu load
> > */
> > - } else if (conn->total_credits == 0) {
> > - credits_granted = 1;
> > }
> >
> > conn->total_credits += credits_granted;
> > @@ -371,7 +358,6 @@ int smb2_set_rsp_credits(struct ksmbd_work *work)
> > /* Update CreditRequest in last request */
> > hdr->CreditRequest = cpu_to_le16(work->credits_granted);
> > }
> > -out:
> > ksmbd_debug(SMB,
> > "credits: requested[%d] granted[%d] total_granted[%d]\n",
> > credits_requested, credits_granted,
> > @@ -692,13 +678,18 @@ int setup_async_work(struct ksmbd_work *work, void
> > (*fn)(void **), void **arg)
> >
> > void smb2_send_interim_resp(struct ksmbd_work *work, __le32 status)
> > {
> > - struct smb2_hdr *rsp_hdr;
> > + struct smb2_hdr *rsp_hdr = work->response_buf;
> > +
> > + work->multiRsp = 1;
> > + if (status != STATUS_CANCELLED) {
> > + spin_lock(&work->conn->credits_lock);
> > + smb2_set_rsp_credits(work);
> Can you explain why this code is needed in smb2_send_interim_resp() ?
>
As I wrote above, a server should grant credits to an interim
response.
> > + spin_unlock(&work->conn->credits_lock);
> > + }
> >
> > - rsp_hdr = work->response_buf;
> > smb2_set_err_rsp(work);
> > rsp_hdr->Status = status;
> >
> > - work->multiRsp = 1;
> > ksmbd_conn_write(work);
> > rsp_hdr->Status = 0;
> > work->multiRsp = 0;
> > @@ -1233,6 +1224,7 @@ int smb2_handle_negotiate(struct ksmbd_work *work)
> >
> > conn->srv_sec_mode = le16_to_cpu(rsp->SecurityMode);
> > ksmbd_conn_set_need_negotiate(work);
> > + conn->total_credits = 0;
> This line is needed ?
Yes, conn->total_credits becomes 0 when receiving a SMB2_NEGOTIATION
request. But init_smbX_X_server functions are called many times and
conn->total_credits is set to 1 in these functions while negotiation.
>
> Thanks!
> >
> > err_out:
> > if (rc < 0)
> > --
> > 2.25.1
> >
> >
--
Thanks,
Hyunchul
