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;
+ }
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;
}
--
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