3 files changed, 6 insertions, 1 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 17ba6b995659..f005b5bebdc7 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -207,7 +207,6 @@ error_0:
 static void nfs4_shutdown_session(struct nfs_client *clp)
 {
         if (nfs4_has_session(clp)) {
-                nfs4_deviceid_purge_client(clp);
                 nfs4_destroy_session(clp->cl_session);
                 nfs4_destroy_clientid(clp);
         }
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b8323aa7b543..bdf7e52943c8 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -80,6 +80,9 @@ 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;
@@ -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;
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index fbb78fb09bd2..f58325a1d8fb 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -25,6 +25,7 @@ struct nfs41_impl_id;
  */
 struct nfs_client {
         atomic_t                cl_count;
+        atomic_t                cl_mds_count;
         int                     cl_cons_state;  /* current construction state (-ve: init error) */
 #define NFS_CS_READY            0               /* ready to be used */
 #define NFS_CS_INITING          1               /* busy initialising */