NFSv4.1: Kill nfs4_ds_disconnect()

There is nothing to prevent another thread from dereferencing ds->ds_clp
during or after the call to nfs4_ds_disconnect(), and Oopsing due to the
resulting NULL pointer.

Instead, we should just rely on filelayout_mark_devid_invalid() to keep
us out of trouble by avoiding that deviceid.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4filelayout.c

@@ -207,7 +207,6 @@ static int filelayout_async_handle_error(struct rpc_task *task,
 		clear_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags);
 		_pnfs_return_layout(inode);
 		rpc_wake_up(&tbl->slot_tbl_waitq);
-		nfs4_ds_disconnect(clp);
 		/* fall through */
 	default:
 reset:

fs/nfs/nfs4filelayout.h

@@ -149,6 +149,5 @@ extern void nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr);
 extern void nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr);
 struct nfs4_file_layout_dsaddr *
 filelayout_get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id, gfp_t gfp_flags);
-void nfs4_ds_disconnect(struct nfs_client *clp);
 
 #endif /* FS_NFS_NFS4FILELAYOUT_H */

fs/nfs/nfs4filelayoutdev.c

@@ -148,28 +148,6 @@ _data_server_lookup_locked(const struct list_head *dsaddrs)
 	return NULL;
 }
 
-/*
- * Lookup DS by nfs_client pointer. Zero data server client pointer
- */
-void nfs4_ds_disconnect(struct nfs_client *clp)
-{
-	struct nfs4_pnfs_ds *ds;
-	struct nfs_client *found = NULL;
-
-	dprintk("%s clp %p\n", __func__, clp);
-	spin_lock(&nfs4_ds_cache_lock);
-	list_for_each_entry(ds, &nfs4_data_server_cache, ds_node)
-		if (ds->ds_clp && ds->ds_clp == clp) {
-			found = ds->ds_clp;
-			ds->ds_clp = NULL;
-		}
-	spin_unlock(&nfs4_ds_cache_lock);
-	if (found) {
-		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
-		nfs_put_client(clp);
-	}
-}
-
 /*
  * Create an rpc connection to the nfs4_pnfs_ds data server
  * Currently only supports IPv4 and IPv6 addresses