NFSv4.1: Fix session initialisation races

Session initialisation is not complete until the lease manager
has run. We need to ensure that both nfs4_init_session and
nfs4_init_ds_session do so, and that they check for any resulting
errors in clp->cl_cons_state.

Only after this is done, can nfs4_ds_connect check the contents
of clp->cl_exchange_flags.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Andy Adamson <andros@netapp.com>

1 files changed, 52 insertions, 27 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 0d46fe449f0b..c856298def7d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5603,53 +5603,78 @@ int nfs4_proc_destroy_session(struct nfs4_session *session)
         return status;
 }
 
+/*
+ * With sessions, the client is not marked ready until after a
+ * successful EXCHANGE_ID and CREATE_SESSION.
+ *
+ * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
+ * other versions of NFS can be tried.
+ */
+static int nfs41_check_session_ready(struct nfs_client *clp)
+{
+        int ret;
+        
+        if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
+                ret = nfs4_client_recover_expired_lease(clp);
+                if (ret)
+                        return ret;
+        }
+        if (clp->cl_cons_state < NFS_CS_READY)
+                return -EPROTONOSUPPORT;
+        return 0;
+}
+
 int nfs4_init_session(struct nfs_server *server)
 {
         struct nfs_client *clp = server->nfs_client;
         struct nfs4_session *session;
         unsigned int rsize, wsize;
-        int ret;
 
         if (!nfs4_has_session(clp))
                 return 0;
 
         session = clp->cl_session;
-        if (!test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state))
-                return 0;
+        spin_lock(&clp->cl_lock);
+        if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
 
-        rsize = server->rsize;
-        if (rsize == 0)
-                rsize = NFS_MAX_FILE_IO_SIZE;
-        wsize = server->wsize;
-        if (wsize == 0)
-                wsize = NFS_MAX_FILE_IO_SIZE;
+                rsize = server->rsize;
+                if (rsize == 0)
+                        rsize = NFS_MAX_FILE_IO_SIZE;
+                wsize = server->wsize;
+                if (wsize == 0)
+                        wsize = NFS_MAX_FILE_IO_SIZE;
 
-        session->fc_attrs.max_rqst_sz = wsize + nfs41_maxwrite_overhead;
-        session->fc_attrs.max_resp_sz = rsize + nfs41_maxread_overhead;
+                session->fc_attrs.max_rqst_sz = wsize + nfs41_maxwrite_overhead;
+                session->fc_attrs.max_resp_sz = rsize + nfs41_maxread_overhead;
+        }
+        spin_unlock(&clp->cl_lock);
 
-        ret = nfs4_recover_expired_lease(server);
-        if (!ret)
-                ret = nfs4_check_client_ready(clp);
-        return ret;
+        return nfs41_check_session_ready(clp);
 }
 
-int nfs4_init_ds_session(struct nfs_client *clp)
+int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
 {
         struct nfs4_session *session = clp->cl_session;
         int ret;
 
-        if (!test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state))
-                return 0;
-
-        ret = nfs4_client_recover_expired_lease(clp);
-        if (!ret)
-                /* Test for the DS role */
-                if (!is_ds_client(clp))
-                        ret = -ENODEV;
-        if (!ret)
-                ret = nfs4_check_client_ready(clp);
-        return ret;
+        spin_lock(&clp->cl_lock);
+        if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
+                /*
+                 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
+                 * DS lease to be equal to the MDS lease.
+                 */
+                clp->cl_lease_time = lease_time;
+                clp->cl_last_renewal = jiffies;
+        }
+        spin_unlock(&clp->cl_lock);
 
+        ret = nfs41_check_session_ready(clp);
+        if (ret)
+                return ret;
+        /* Test for the DS role */
+        if (!is_ds_client(clp))
+                return -ENODEV;
+        return 0;
 }
 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);