From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
If the client were to disappear from underneath us while we're holding
a session reference, things would be bad. This cleanup ensures that
it cannot.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 112 +++++++++++++++++++++++++++++++---------------------
fs/nfsd/state.h | 2 -
2 files changed, 68 insertions(+), 46 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 20e23dbf39e5..bd753abdc405 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -102,12 +102,6 @@ static bool is_session_dead(struct nfsd4_session *ses)
return ses->se_flags & NFS4_SESSION_DEAD;
}
-void nfsd4_put_session(struct nfsd4_session *ses)
-{
- if (atomic_dec_and_test(&ses->se_ref) && is_session_dead(ses))
- free_session(ses);
-}
-
static __be32 mark_session_dead_locked(struct nfsd4_session *ses, int ref_held_by_me)
{
if (atomic_read(&ses->se_ref) > ref_held_by_me)
@@ -116,14 +110,6 @@ static __be32 mark_session_dead_locked(struct nfsd4_session *ses, int ref_held_b
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
nfs4_unlock_state(void)
{
@@ -202,6 +188,39 @@ static void put_client_renew_locked(struct nfs4_client *clp)
renew_client_locked(clp);
}
+static __be32 nfsd4_get_session_locked(struct nfsd4_session *ses)
+{
+ __be32 status;
+
+ if (is_session_dead(ses))
+ return nfserr_badsession;
+ status = get_client_locked(ses->se_client);
+ if (status)
+ return status;
+ atomic_inc(&ses->se_ref);
+ return nfs_ok;
+}
+
+static void nfsd4_put_session_locked(struct nfsd4_session *ses)
+{
+ struct nfs4_client *clp = ses->se_client;
+
+ if (atomic_dec_and_test(&ses->se_ref) && is_session_dead(ses))
+ free_session(ses);
+ put_client_renew_locked(clp);
+}
+
+static void nfsd4_put_session(struct nfsd4_session *ses)
+{
+ struct nfs4_client *clp = ses->se_client;
+ struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+ spin_lock(&nn->client_lock);
+ nfsd4_put_session_locked(ses);
+ spin_unlock(&nn->client_lock);
+}
+
+
static inline u32
opaque_hashval(const void *ptr, int nbytes)
{
@@ -1154,7 +1173,7 @@ static void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, stru
/* caller must hold client_lock */
static struct nfsd4_session *
-find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
+__find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
{
struct nfsd4_session *elem;
int idx;
@@ -1174,6 +1193,24 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
return NULL;
}
+static struct nfsd4_session *
+find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
+ __be32 *ret)
+{
+ struct nfsd4_session *session;
+ __be32 status = nfserr_badsession;
+
+ session = __find_in_sessionid_hashtbl(sessionid, net);
+ if (!session)
+ goto out;
+ status = nfsd4_get_session_locked(session);
+ if (status)
+ session = NULL;
+out:
+ *ret = status;
+ return session;
+}
+
/* caller must hold client_lock */
static void
unhash_session(struct nfsd4_session *ses)
@@ -2194,17 +2231,17 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
__be32 status;
struct nfsd4_conn *conn;
struct nfsd4_session *session;
- struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+ struct net *net = SVC_NET(rqstp);
+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
if (!nfsd4_last_compound_op(rqstp))
return nfserr_not_only_op;
nfs4_lock_state();
spin_lock(&nn->client_lock);
- session = find_in_sessionid_hashtbl(&bcts->sessionid, SVC_NET(rqstp));
+ session = find_in_sessionid_hashtbl(&bcts->sessionid, net, &status);
spin_unlock(&nn->client_lock);
- status = nfserr_badsession;
if (!session)
- goto out;
+ goto out_no_session;
status = nfserr_wrong_cred;
if (!mach_creds_match(session->se_client, rqstp))
goto out;
@@ -2218,6 +2255,8 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
nfsd4_init_conn(rqstp, conn, session);
status = nfs_ok;
out:
+ nfsd4_put_session(session);
+out_no_session:
nfs4_unlock_state();
return status;
}
@@ -2237,7 +2276,8 @@ nfsd4_destroy_session(struct svc_rqst *r,
struct nfsd4_session *ses;
__be32 status;
int ref_held_by_me = 0;
- struct nfsd_net *nn = net_generic(SVC_NET(r), nfsd_net_id);
+ struct net *net = SVC_NET(r);
+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
nfs4_lock_state();
status = nfserr_not_only_op;
@@ -2248,14 +2288,12 @@ nfsd4_destroy_session(struct svc_rqst *r,
}
dump_sessionid(__func__, &sessionid->sessionid);
spin_lock(&nn->client_lock);
- ses = find_in_sessionid_hashtbl(&sessionid->sessionid, SVC_NET(r));
- status = nfserr_badsession;
+ ses = find_in_sessionid_hashtbl(&sessionid->sessionid, net, &status);
if (!ses)
goto out_client_lock;
status = nfserr_wrong_cred;
if (!mach_creds_match(ses->se_client, r))
- goto out_client_lock;
- nfsd4_get_session_locked(ses);
+ goto out_put_session;
status = mark_session_dead_locked(ses, 1 + ref_held_by_me);
if (status)
goto out_put_session;
@@ -2267,7 +2305,7 @@ nfsd4_destroy_session(struct svc_rqst *r,
spin_lock(&nn->client_lock);
status = nfs_ok;
out_put_session:
- nfsd4_put_session(ses);
+ nfsd4_put_session_locked(ses);
out_client_lock:
spin_unlock(&nn->client_lock);
out:
@@ -2342,7 +2380,8 @@ nfsd4_sequence(struct svc_rqst *rqstp,
struct nfsd4_conn *conn;
__be32 status;
int buflen;
- struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+ struct net *net = SVC_NET(rqstp);
+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
if (resp->opcnt != 1)
return nfserr_sequence_pos;
@@ -2356,17 +2395,10 @@ nfsd4_sequence(struct svc_rqst *rqstp,
return nfserr_jukebox;
spin_lock(&nn->client_lock);
- status = nfserr_badsession;
- session = find_in_sessionid_hashtbl(&seq->sessionid, SVC_NET(rqstp));
+ session = find_in_sessionid_hashtbl(&seq->sessionid, net, &status);
if (!session)
goto out_no_session;
clp = session->se_client;
- 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))
@@ -2450,9 +2482,7 @@ out_no_session:
spin_unlock(&nn->client_lock);
return status;
out_put_session:
- nfsd4_put_session(session);
-out_put_client:
- put_client_renew_locked(clp);
+ nfsd4_put_session_locked(session);
goto out_no_session;
}
@@ -2462,18 +2492,12 @@ nfsd4_sequence_done(struct nfsd4_compoundres *resp)
struct nfsd4_compound_state *cs = &resp->cstate;
if (nfsd4_has_session(cs)) {
- struct nfs4_client *clp = cs->session->se_client;
- struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
-
if (cs->status != nfserr_replay_cache) {
nfsd4_store_cache_entry(resp);
cs->slot->sl_flags &= ~NFSD4_SLOT_INUSE;
}
- /* Renew the clientid on success and on replay */
- spin_lock(&nn->client_lock);
+ /* Drop session reference that was taken in nfsd4_sequence() */
nfsd4_put_session(cs->session);
- put_client_renew_locked(clp);
- spin_unlock(&nn->client_lock);
}
}
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index dee801d67e4a..d928c444f91e 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -212,8 +212,6 @@ struct nfsd4_session {
struct nfsd4_slot *se_slots[]; /* forward channel slots */
};
-extern void nfsd4_put_session(struct nfsd4_session *ses);
-
/* formatted contents of nfs4_sessionid */
struct nfsd4_sessionid {
clientid_t clientid;
--
1.9.3
--
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