nfsd41: free_session/free_client must be called under the client_lock
The session client is manipulated under the client_lock hence
both free_session and nfsd4_del_conns must be called under this lock.
This patch adds a BUG_ON that checks this condition in the
respective functions and implements the missing locks.
nfsd4_{get,put}_session helpers were moved to the C file that uses them
so to prevent use from external files and an unlocked version of
nfsd4_put_session is provided for external use from nfs4xdr.c
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 97dd2c7..8670863 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -95,6 +95,19 @@
mutex_lock(&client_mutex);
}
+static void free_session(struct kref *);
+
+/* Must be called under the client_lock */
+static void nfsd4_put_session_locked(struct nfsd4_session *ses)
+{
+ kref_put(&ses->se_ref, free_session);
+}
+
+static void nfsd4_get_session(struct nfsd4_session *ses)
+{
+ kref_get(&ses->se_ref);
+}
+
void
nfs4_unlock_state(void)
{
@@ -836,11 +849,12 @@
spin_unlock(&clp->cl_lock);
}
-void free_session(struct kref *kref)
+static void free_session(struct kref *kref)
{
struct nfsd4_session *ses;
int mem;
+ BUG_ON(!spin_is_locked(&client_lock));
ses = container_of(kref, struct nfsd4_session, se_ref);
nfsd4_del_conns(ses);
spin_lock(&nfsd_drc_lock);
@@ -851,6 +865,13 @@
kfree(ses);
}
+void nfsd4_put_session(struct nfsd4_session *ses)
+{
+ spin_lock(&client_lock);
+ nfsd4_put_session_locked(ses);
+ spin_unlock(&client_lock);
+}
+
static struct nfsd4_session *alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp, struct nfsd4_create_session *cses)
{
struct nfsd4_session *new;
@@ -898,7 +919,9 @@
status = nfsd4_new_conn_from_crses(rqstp, new);
/* whoops: benny points out, status is ignored! (err, or bogus) */
if (status) {
+ spin_lock(&client_lock);
free_session(&new->se_ref);
+ spin_unlock(&client_lock);
return NULL;
}
if (cses->flags & SESSION4_BACK_CHAN) {
@@ -1010,12 +1033,13 @@
static inline void
free_client(struct nfs4_client *clp)
{
+ BUG_ON(!spin_is_locked(&client_lock));
while (!list_empty(&clp->cl_sessions)) {
struct nfsd4_session *ses;
ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
se_perclnt);
list_del(&ses->se_perclnt);
- nfsd4_put_session(ses);
+ nfsd4_put_session_locked(ses);
}
if (clp->cl_cred.cr_group_info)
put_group_info(clp->cl_cred.cr_group_info);
@@ -1184,7 +1208,9 @@
if (princ) {
clp->cl_principal = kstrdup(princ, GFP_KERNEL);
if (clp->cl_principal == NULL) {
+ spin_lock(&client_lock);
free_client(clp);
+ spin_unlock(&client_lock);
return NULL;
}
}
@@ -1812,9 +1838,10 @@
nfsd4_probe_callback_sync(ses->se_client);
nfs4_unlock_state();
+ spin_lock(&client_lock);
nfsd4_del_conns(ses);
-
- nfsd4_put_session(ses);
+ nfsd4_put_session_locked(ses);
+ spin_unlock(&client_lock);
status = nfs_ok;
out:
dprintk("%s returns %d\n", __func__, ntohl(status));