On 08/26/2009 12:59 AM, J. Bruce Fields wrote:
> On Tue, Aug 25, 2009 at 08:02:41PM +0300, Benny Halevy wrote:
>> On Aug. 25, 2009, 16:18 +0300, "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
>>> On Tue, Aug 25, 2009 at 10:06:34AM +0300, Benny Halevy wrote:
>>>> On Aug. 24, 2009, 19:29 +0300, "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
>>>>> On Thu, Aug 20, 2009 at 03:21:56AM +0300, Benny Halevy wrote:
>>>>>> nfsd4_sequence() should not renew the client state if the session was not
>>>>>> found or if there was a bad slot. This will also avoid dereferencing a
>>>>>> null session pointer.
>>>>>>
>>>>>> FIXME: until we work out the state locking so we can use a
>>>>>> spin lock to protect the cl_lru we need to take the state_lock
>>>>>> to renew the client.
>>>>> Is that first paragraph left over from some previous iteration of this
>>>>> patch?
>>>> Not really.
>>>> It sort of sets up the stage for the state lock elimination project.
>>>> That said, feel free to remove these lines as they are not particularly
>>>> important for understanding what this patch does or how to do it better.
>>>
>>> Note I was referring to "should not renew..." That seems to describe a
>>> problem that has already been fixed.
>>
>> Hmm, apparently this came from "Do not renew state on error"
>> which was squashed together with this patch.
>> The text is still valid though somewhat unrelated to this patch's
>> title. Maybe a better title would be the original one:
>> ""Do not renew state on error"
>
> The title's right, it's just the comment that went stale. I've applied
> for 2.6.32 as follows.
>
> --b.
>
> commit fdf7875040506ca7e595dffef56cbd81ae6b384b
> Author: Benny Halevy <bhalevy@xxxxxxxxxxx>
> Date: Thu Aug 20 03:21:56 2009 +0300
>
> nfsd41: renew_client must be called under the state lock
>
> Until we work out the state locking so we can use a spin lock to protect
> the cl_lru, we need to take the state_lock to renew the client.
>
> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> [nfsd41: Do not renew state on error]
> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@xxxxxxxxxx>
> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index d2a0524..8e5ac49 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1463,12 +1463,16 @@ nfsd4_sequence(struct svc_rqst *rqstp,
> spin_lock(&sessionid_lock);
> status = nfserr_badsession;
> session = find_in_sessionid_hashtbl(&seq->sessionid);
> - if (!session)
> - goto out;
> + if (!session) {
> + spin_unlock(&sessionid_lock);
> + goto err;
> + }
>
> status = nfserr_badslot;
> - if (seq->slotid >= session->se_fchannel.maxreqs)
> - goto out;
> + if (seq->slotid >= session->se_fchannel.maxreqs) {
> + spin_unlock(&sessionid_lock);
> + goto err;
> + }
>
A spin_unlock is a big and delicate inlined code site
Why not do a "goto err_unlock" or something
Boaz
> slot = &session->se_slots[seq->slotid];
> dprintk("%s: slotid %d\n", __func__, seq->slotid);
> @@ -1481,10 +1485,12 @@ nfsd4_sequence(struct svc_rqst *rqstp,
> * for nfsd4_svc_encode_compoundres processing */
> status = nfsd4_replay_cache_entry(resp, seq);
> cstate->status = nfserr_replay_cache;
> - goto replay_cache;
> - }
> - if (status)
> goto out;
> + }
> + if (status) {
> + spin_unlock(&sessionid_lock);
> + goto err;
> + }
>
> /* Success! bump slot seqid */
> slot->sl_inuse = true;
> @@ -1497,15 +1503,17 @@ nfsd4_sequence(struct svc_rqst *rqstp,
> cstate->slot = slot;
> cstate->session = session;
>
> -replay_cache:
> - /* Renew the clientid on success and on replay.
> - * Hold a session reference until done processing the compound:
> + /* Hold a session reference until done processing the compound:
> * nfsd4_put_session called only if the cstate slot is set.
> */
> - renew_client(session->se_client);
> nfsd4_get_session(session);
> out:
> spin_unlock(&sessionid_lock);
> + /* Renew the clientid on success and on replay */
> + nfs4_lock_state();
> + renew_client(session->se_client);
> + nfs4_unlock_state();
> +err:
> dprintk("%s: return %d\n", __func__, ntohl(status));
> return status;
> }
> _______________________________________________
> pNFS mailing list
> pNFS@xxxxxxxxxxxxx
> http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
