nfsd4: don't destroy in-use session
This changes session destruction to be similar to client destruction in
that attempts to destroy a session while in use (which should be rare
corner cases) result in DELAY. This simplifies things somewhat and
helps meet a coming 4.2 requirement.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3b4ce41..2fd0155 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -94,17 +94,32 @@
mutex_lock(&client_mutex);
}
-static void free_session(struct kref *);
+static void free_session(struct nfsd4_session *);
-/* Must be called under the client_lock */
-static void nfsd4_put_session_locked(struct nfsd4_session *ses)
+void nfsd4_put_session(struct nfsd4_session *ses)
{
- kref_put(&ses->se_ref, free_session);
+ atomic_dec(&ses->se_ref);
}
-static void nfsd4_get_session(struct nfsd4_session *ses)
+static bool is_session_dead(struct nfsd4_session *ses)
{
- kref_get(&ses->se_ref);
+ return ses->se_flags & NFS4_SESSION_DEAD;
+}
+
+static __be32 mark_session_dead_locked(struct nfsd4_session *ses)
+{
+ if (atomic_read(&ses->se_ref))
+ return nfserr_jukebox;
+ ses->se_flags |= NFS4_SESSION_DEAD;
+ return nfs_ok;
+}
+
+static __be32 nfsd4_get_session_locked(struct nfsd4_session *ses)
+{
+ if (is_session_dead(ses))
+ return nfserr_badsession;
+ atomic_inc(&ses->se_ref);
+ return nfs_ok;
}
void
@@ -935,28 +950,15 @@
kfree(ses);
}
-static void free_session(struct kref *kref)
+static void free_session(struct nfsd4_session *ses)
{
- struct nfsd4_session *ses;
- struct nfsd_net *nn;
-
- ses = container_of(kref, struct nfsd4_session, se_ref);
- nn = net_generic(ses->se_client->net, nfsd_net_id);
+ struct nfsd_net *nn = net_generic(ses->se_client->net, nfsd_net_id);
lockdep_assert_held(&nn->client_lock);
nfsd4_del_conns(ses);
__free_session(ses);
}
-void nfsd4_put_session(struct nfsd4_session *ses)
-{
- struct nfsd_net *nn = net_generic(ses->se_client->net, nfsd_net_id);
-
- spin_lock(&nn->client_lock);
- nfsd4_put_session_locked(ses);
- spin_unlock(&nn->client_lock);
-}
-
static struct nfsd4_session *alloc_session(struct nfsd4_channel_attrs *fchan,
struct nfsd_net *nn)
{
@@ -997,7 +999,7 @@
new->se_flags = cses->flags;
new->se_cb_prog = cses->callback_prog;
new->se_cb_sec = cses->cb_sec;
- kref_init(&new->se_ref);
+ atomic_set(&new->se_ref, 0);
idx = hash_sessionid(&new->se_sessionid);
spin_lock(&nn->client_lock);
list_add(&new->se_hash, &nn->sessionid_hashtbl[idx]);
@@ -1095,7 +1097,8 @@
ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
se_perclnt);
list_del(&ses->se_perclnt);
- nfsd4_put_session_locked(ses);
+ WARN_ON_ONCE(atomic_read(&ses->se_ref));
+ free_session(ses);
}
free_svc_cred(&clp->cl_cred);
kfree(clp->cl_name.data);
@@ -1976,15 +1979,16 @@
status = nfserr_badsession;
if (!ses)
goto out_client_lock;
-
+ status = mark_session_dead_locked(ses);
+ if (status)
+ goto out_client_lock;
unhash_session(ses);
spin_unlock(&nn->client_lock);
nfsd4_probe_callback_sync(ses->se_client);
spin_lock(&nn->client_lock);
- nfsd4_del_conns(ses);
- nfsd4_put_session_locked(ses);
+ free_session(ses);
status = nfs_ok;
out_client_lock:
spin_unlock(&nn->client_lock);
@@ -2075,18 +2079,21 @@
status = get_client_locked(clp);
if (status)
goto out_no_session;
+ status = nfsd4_get_session_locked(session);
+ if (status)
+ goto out_put_client;
status = nfserr_too_many_ops;
if (nfsd4_session_too_many_ops(rqstp, session))
- goto out_put_client;
+ goto out_put_session;
status = nfserr_req_too_big;
if (nfsd4_request_too_big(rqstp, session))
- goto out_put_client;
+ goto out_put_session;
status = nfserr_badslot;
if (seq->slotid >= session->se_fchannel.maxreqs)
- goto out_put_client;
+ goto out_put_session;
slot = session->se_slots[seq->slotid];
dprintk("%s: slotid %d\n", __func__, seq->slotid);
@@ -2101,7 +2108,7 @@
if (status == nfserr_replay_cache) {
status = nfserr_seq_misordered;
if (!(slot->sl_flags & NFSD4_SLOT_INITIALIZED))
- goto out_put_client;
+ goto out_put_session;
cstate->slot = slot;
cstate->session = session;
/* Return the cached reply status and set cstate->status
@@ -2111,7 +2118,7 @@
goto out;
}
if (status)
- goto out_put_client;
+ goto out_put_session;
nfsd4_sequence_check_conn(conn, session);
conn = NULL;
@@ -2128,7 +2135,6 @@
cstate->session = session;
out:
- nfsd4_get_session(cstate->session);
switch (clp->cl_cb_state) {
case NFSD4_CB_DOWN:
seq->status_flags = SEQ4_STATUS_CB_PATH_DOWN;
@@ -2143,6 +2149,8 @@
kfree(conn);
spin_unlock(&nn->client_lock);
return status;
+out_put_session:
+ nfsd4_put_session(session);
out_put_client:
put_client_renew_locked(clp);
goto out_no_session;