diff mbox series

[RFC,v15,06/11] NFSD: Update find_clp_in_name_tree() to handle courtesy clients

Message ID 1646440633-3542-7-git-send-email-dai.ngo@oracle.com (mailing list archive)
State New, archived
Headers show
Series NFSD: Initial implementation of NFSv4 Courteous Server | expand

Commit Message

Dai Ngo March 5, 2022, 12:37 a.m. UTC 
Update find_clp_in_name_tree:
 . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
 . if courtesy client was found then clear CLIENT_COURTESY and
   set CLIENT_RECONNECTED so callers can take appropriate action.

Update find_confirmed_client_by_name to discard the courtesy
client; set CLIENT_EXPIRED.

Update nfsd4_setclientid to expire the confirmed courtesy client
to prevent multiple confirmed clients with the same name on the
the conf_id_hashtbl list.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

Comments

Chuck Lever March 9, 2022, 10:08 p.m. UTC | #1 
> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Update find_clp_in_name_tree:
> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
> . if courtesy client was found then clear CLIENT_COURTESY and
>   set CLIENT_RECONNECTED so callers can take appropriate action.
> 
> Update find_confirmed_client_by_name to discard the courtesy
> client; set CLIENT_EXPIRED.
> 
> Update nfsd4_setclientid to expire the confirmed courtesy client
> to prevent multiple confirmed clients with the same name on the
> the conf_id_hashtbl list.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 52 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index b16f689f34c3..f42d72a8f5ca 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1929,6 +1929,34 @@ __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
> 	return NULL;
> }
> 
> +static void
> +nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
> +{
> +	spin_lock(&clp->cl_cs_lock);
> +	set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> +	spin_unlock(&clp->cl_cs_lock);
> +}
> +
> +static bool
> +nfs4_is_courtesy_client_expired(struct nfs4_client *clp)
> +{
> +	clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
> +	/* need to sync with thread resolving lock/deleg conflict */
> +	spin_lock(&clp->cl_cs_lock);
> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	/*
> +	 * clear CLIENT_COURTESY flag to prevent it from being
> +	 * destroyed by thread trying to resolve conflicts.
> +	 */
> +	if (test_and_clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
> +		set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
> +	spin_unlock(&clp->cl_cs_lock);
> +	return false;
> +}
> +
> static struct nfsd4_session *
> find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
> 		__be32 *ret)
> @@ -2834,8 +2862,11 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
> 			node = node->rb_left;
> 		else if (cmp < 0)
> 			node = node->rb_right;
> -		else
> +		else {
> +			if (nfs4_is_courtesy_client_expired(clp))
> +				return NULL;
> 			return clp;
> +		}
> 	}
> 	return NULL;
> }
> @@ -2914,8 +2945,15 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
> static struct nfs4_client *
> find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
> {
> +	struct nfs4_client *clp;
> +
> 	lockdep_assert_held(&nn->client_lock);
> -	return find_clp_in_name_tree(name, &nn->conf_name_tree);
> +	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
> +	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
> +		nfsd4_discard_courtesy_clnt(clp);
> +		clp = NULL;
> +	}
> +	return clp;
> }

2983 static struct nfs4_client *
2984 find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
2985 {
2986         lockdep_assert_held(&nn->client_lock);
2987         return find_clp_in_name_tree(name, &nn->unconf_name_tree);
2988 }

Notice the difference:

find_confirmed() does find_clp_in_name_tree(&nn->conf_name_tree);
                                                 ^^^^

find_unconfirmed() does find_clp_in_name_tree(&nn->unconf_name_tree);
                                                   ^^^^^^

I don't think we will ever find a client in unconf_name_tree that
has CLIENT_RECONNECTED set, will we? So it seems to me that you
can safely move the CLIENT_RECONNECTED test into
find_clp_in_name_tree() in all cases, maybe?

Or think about it this way: is it possible for an unconfirmed
client to become a courtesy client? I don't think it is.


> @@ -4032,12 +4070,19 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> 	struct nfs4_client	*unconf = NULL;
> 	__be32 			status;
> 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
> +	struct nfs4_client	*cclient = NULL;
> 
> 	new = create_client(clname, rqstp, &clverifier);
> 	if (new == NULL)
> 		return nfserr_jukebox;
> 	spin_lock(&nn->client_lock);
> -	conf = find_confirmed_client_by_name(&clname, nn);
> +	/* find confirmed client by name */
> +	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
> +	if (conf && test_bit(NFSD4_CLIENT_RECONNECTED, &conf->cl_flags)) {
> +		cclient = conf;
> +		conf = NULL;
> +	}
> +
> 	if (conf && client_has_state(conf)) {
> 		status = nfserr_clid_inuse;
> 		if (clp_used_exchangeid(conf))
> @@ -4068,7 +4113,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> 	new = NULL;
> 	status = nfs_ok;
> out:
> +	if (cclient)
> +		unhash_client_locked(cclient);
> 	spin_unlock(&nn->client_lock);
> +	if (cclient)
> +		expire_client(cclient);
> 	if (new)
> 		free_client(new);
> 	if (unconf) {
> -- 
> 2.9.5
> 

--
Chuck Lever
Dai Ngo March 10, 2022, 3:11 a.m. UTC | #2 
On 3/9/22 2:08 PM, Chuck Lever III wrote:
>
>> On Mar 4, 2022, at 7:37 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Update find_clp_in_name_tree:
>> . skip client with CLIENT_EXPIRED flag; discarded courtesy client.
>> . if courtesy client was found then clear CLIENT_COURTESY and
>>    set CLIENT_RECONNECTED so callers can take appropriate action.
>>
>> Update find_confirmed_client_by_name to discard the courtesy
>> client; set CLIENT_EXPIRED.
>>
>> Update nfsd4_setclientid to expire the confirmed courtesy client
>> to prevent multiple confirmed clients with the same name on the
>> the conf_id_hashtbl list.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/nfsd/nfs4state.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++---
>> 1 file changed, 52 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index b16f689f34c3..f42d72a8f5ca 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -1929,6 +1929,34 @@ __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
>> 	return NULL;
>> }
>>
>> +static void
>> +nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
>> +{
>> +	spin_lock(&clp->cl_cs_lock);
>> +	set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
>> +	spin_unlock(&clp->cl_cs_lock);
>> +}
>> +
>> +static bool
>> +nfs4_is_courtesy_client_expired(struct nfs4_client *clp)
>> +{
>> +	clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
>> +	/* need to sync with thread resolving lock/deleg conflict */
>> +	spin_lock(&clp->cl_cs_lock);
>> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
>> +		spin_unlock(&clp->cl_cs_lock);
>> +		return true;
>> +	}
>> +	/*
>> +	 * clear CLIENT_COURTESY flag to prevent it from being
>> +	 * destroyed by thread trying to resolve conflicts.
>> +	 */
>> +	if (test_and_clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
>> +		set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
>> +	spin_unlock(&clp->cl_cs_lock);
>> +	return false;
>> +}
>> +
>> static struct nfsd4_session *
>> find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
>> 		__be32 *ret)
>> @@ -2834,8 +2862,11 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
>> 			node = node->rb_left;
>> 		else if (cmp < 0)
>> 			node = node->rb_right;
>> -		else
>> +		else {
>> +			if (nfs4_is_courtesy_client_expired(clp))
>> +				return NULL;
>> 			return clp;
>> +		}
>> 	}
>> 	return NULL;
>> }
>> @@ -2914,8 +2945,15 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
>> static struct nfs4_client *
>> find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
>> {
>> +	struct nfs4_client *clp;
>> +
>> 	lockdep_assert_held(&nn->client_lock);
>> -	return find_clp_in_name_tree(name, &nn->conf_name_tree);
>> +	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
>> +	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
>> +		nfsd4_discard_courtesy_clnt(clp);
>> +		clp = NULL;
>> +	}
>> +	return clp;
>> }
> 2983 static struct nfs4_client *
> 2984 find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
> 2985 {
> 2986         lockdep_assert_held(&nn->client_lock);
> 2987         return find_clp_in_name_tree(name, &nn->unconf_name_tree);
> 2988 }
>
> Notice the difference:
>
> find_confirmed() does find_clp_in_name_tree(&nn->conf_name_tree);
>                                                   ^^^^
>
> find_unconfirmed() does find_clp_in_name_tree(&nn->unconf_name_tree);
>                                                     ^^^^^^
>
> I don't think we will ever find a client in unconf_name_tree that
> has CLIENT_RECONNECTED set, will we?

No.

> So it seems to me that you
> can safely move the CLIENT_RECONNECTED test into
> find_clp_in_name_tree() in all cases, maybe?

nfsd4_setclientid needs to treat the courtesy client a little
differently from find_[un]confirmed_client_by_name. It has to
expire the courtesy client immediately to prevent multiple
confirmed clients with the same name on the the conf_id_hashtbl
list which causes problem for the subsequent setclientid_confirm.

-Dai

>
> Or think about it this way: is it possible for an unconfirmed
> client to become a courtesy client? I don't think it is.
>
>
>> @@ -4032,12 +4070,19 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> 	struct nfs4_client	*unconf = NULL;
>> 	__be32 			status;
>> 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
>> +	struct nfs4_client	*cclient = NULL;
>>
>> 	new = create_client(clname, rqstp, &clverifier);
>> 	if (new == NULL)
>> 		return nfserr_jukebox;
>> 	spin_lock(&nn->client_lock);
>> -	conf = find_confirmed_client_by_name(&clname, nn);
>> +	/* find confirmed client by name */
>> +	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
>> +	if (conf && test_bit(NFSD4_CLIENT_RECONNECTED, &conf->cl_flags)) {
>> +		cclient = conf;
>> +		conf = NULL;
>> +	}
>> +
>> 	if (conf && client_has_state(conf)) {
>> 		status = nfserr_clid_inuse;
>> 		if (clp_used_exchangeid(conf))
>> @@ -4068,7 +4113,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> 	new = NULL;
>> 	status = nfs_ok;
>> out:
>> +	if (cclient)
>> +		unhash_client_locked(cclient);
>> 	spin_unlock(&nn->client_lock);
>> +	if (cclient)
>> +		expire_client(cclient);
>> 	if (new)
>> 		free_client(new);
>> 	if (unconf) {
>> -- 
>> 2.9.5
>>
> --
> Chuck Lever
>
>
>
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b16f689f34c3..f42d72a8f5ca 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1929,6 +1929,34 @@  __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
 	return NULL;
 }
 
+static void
+nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
+{
+	spin_lock(&clp->cl_cs_lock);
+	set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
+	spin_unlock(&clp->cl_cs_lock);
+}
+
+static bool
+nfs4_is_courtesy_client_expired(struct nfs4_client *clp)
+{
+	clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
+	/* need to sync with thread resolving lock/deleg conflict */
+	spin_lock(&clp->cl_cs_lock);
+	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
+		spin_unlock(&clp->cl_cs_lock);
+		return true;
+	}
+	/*
+	 * clear CLIENT_COURTESY flag to prevent it from being
+	 * destroyed by thread trying to resolve conflicts.
+	 */
+	if (test_and_clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
+		set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
+	spin_unlock(&clp->cl_cs_lock);
+	return false;
+}
+
 static struct nfsd4_session *
 find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
 		__be32 *ret)
@@ -2834,8 +2862,11 @@  find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
 			node = node->rb_left;
 		else if (cmp < 0)
 			node = node->rb_right;
-		else
+		else {
+			if (nfs4_is_courtesy_client_expired(clp))
+				return NULL;
 			return clp;
+		}
 	}
 	return NULL;
 }
@@ -2914,8 +2945,15 @@  static bool clp_used_exchangeid(struct nfs4_client *clp)
 static struct nfs4_client *
 find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
 {
+	struct nfs4_client *clp;
+
 	lockdep_assert_held(&nn->client_lock);
-	return find_clp_in_name_tree(name, &nn->conf_name_tree);
+	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
+	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		nfsd4_discard_courtesy_clnt(clp);
+		clp = NULL;
+	}
+	return clp;
 }
 
 static struct nfs4_client *
@@ -4032,12 +4070,19 @@  nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfs4_client	*unconf = NULL;
 	__be32 			status;
 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	struct nfs4_client	*cclient = NULL;
 
 	new = create_client(clname, rqstp, &clverifier);
 	if (new == NULL)
 		return nfserr_jukebox;
 	spin_lock(&nn->client_lock);
-	conf = find_confirmed_client_by_name(&clname, nn);
+	/* find confirmed client by name */
+	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
+	if (conf && test_bit(NFSD4_CLIENT_RECONNECTED, &conf->cl_flags)) {
+		cclient = conf;
+		conf = NULL;
+	}
+
 	if (conf && client_has_state(conf)) {
 		status = nfserr_clid_inuse;
 		if (clp_used_exchangeid(conf))
@@ -4068,7 +4113,11 @@  nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	new = NULL;
 	status = nfs_ok;
 out:
+	if (cclient)
+		unhash_client_locked(cclient);
 	spin_unlock(&nn->client_lock);
+	if (cclient)
+		expire_client(cclient);
 	if (new)
 		free_client(new);
 	if (unconf) {