1 files changed, 9 insertions, 4 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b8323aa7b543..bbc49caa7a82 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -70,6 +70,10 @@ find_pnfs_driver(u32 id)
 
         spin_lock(&pnfs_spinlock);
         local = find_pnfs_driver_locked(id);
+        if (local != NULL && !try_module_get(local->owner)) {
+                dprintk("%s: Could not grab reference on module\n", __func__);
+                local = NULL;
+        }
         spin_unlock(&pnfs_spinlock);
         return local;
 }
@@ -80,6 +84,9 @@ unset_pnfs_layoutdriver(struct nfs_server *nfss)
         if (nfss->pnfs_curr_ld) {
                 if (nfss->pnfs_curr_ld->clear_layoutdriver)
                         nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
+                /* Decrement the MDS count. Purge the deviceid cache if zero */
+                if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
+                        nfs4_deviceid_purge_client(nfss->nfs_client);
                 module_put(nfss->pnfs_curr_ld->owner);
         }
         nfss->pnfs_curr_ld = NULL;
@@ -115,10 +122,6 @@ set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
                         goto out_no_driver;
                 }
         }
-        if (!try_module_get(ld_type->owner)) {
-                dprintk("%s: Could not grab reference on module\n", __func__);
-                goto out_no_driver;
-        }
         server->pnfs_curr_ld = ld_type;
         if (ld_type->set_layoutdriver
             && ld_type->set_layoutdriver(server, mntfh)) {
@@ -127,6 +130,8 @@ set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
                 module_put(ld_type->owner);
                 goto out_no_driver;
         }
+        /* Bump the MDS count */
+        atomic_inc(&server->nfs_client->cl_mds_count);
 
         dprintk("%s: pNFS module for %u set\n", __func__, id);
         return;