nfsd4: delay session removal till free_client

Have unhash_client_locked() remove client and associated sessions from
global hashes, but delay further dismantling till free_client().

(After unhash_client_locked(), the only remaining references outside the
destroying thread are from any connections which have xpt_user callbacks
registered.)

This will simplify locking on session destruction.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 13 insertions, 8 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 2327a8c00862..0f2643dac22a 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -883,6 +883,13 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name)
 static inline void
 free_client(struct nfs4_client *clp)
 {
+        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);
+        }
         if (clp->cl_cred.cr_group_info)
                 put_group_info(clp->cl_cred.cr_group_info);
         kfree(clp->cl_principal);
@@ -909,15 +916,12 @@ release_session_client(struct nfsd4_session *session)
 static inline void
 unhash_client_locked(struct nfs4_client *clp)
 {
+        struct nfsd4_session *ses;
+
         mark_client_expired(clp);
         list_del(&clp->cl_lru);
-        while (!list_empty(&clp->cl_sessions)) {
-                struct nfsd4_session  *ses;
-                ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
-                                 se_perclnt);
-                unhash_session(ses);
-                nfsd4_put_session(ses);
-        }
+        list_for_each_entry(ses, &clp->cl_sessions, se_perclnt)
+                list_del_init(&ses->se_hash);
 }
 
 static void
@@ -1031,6 +1035,8 @@ static struct nfs4_client *create_client(struct xdr_netobj name, char *recdir,
         if (clp == NULL)
                 return NULL;
 
+        INIT_LIST_HEAD(&clp->cl_sessions);
+
         princ = svc_gss_principal(rqstp);
         if (princ) {
                 clp->cl_principal = kstrdup(princ, GFP_KERNEL);
@@ -1047,7 +1053,6 @@ static struct nfs4_client *create_client(struct xdr_netobj name, char *recdir,
         INIT_LIST_HEAD(&clp->cl_strhash);
         INIT_LIST_HEAD(&clp->cl_openowners);
         INIT_LIST_HEAD(&clp->cl_delegations);
-        INIT_LIST_HEAD(&clp->cl_sessions);
         INIT_LIST_HEAD(&clp->cl_lru);
         spin_lock_init(&clp->cl_lock);
         INIT_WORK(&clp->cl_cb_null.cb_work, nfsd4_do_callback_rpc);