NFSv4.1: Ensure memory ordering between nfs4_ds_connect and nfs4_fl_prepare_ds

We need to ensure that the initialisation of the data server nfs_client
structure in nfs4_ds_connect is correctly ordered w.r.t. the read of
ds->ds_clp in nfs4_fl_prepare_ds.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4filelayoutdev.c b/fs/nfs/nfs4filelayoutdev.c
index cd3aef5..c7c295e 100644 (file)
--- a/fs/nfs/nfs4filelayoutdev.c
+++ b/fs/nfs/nfs4filelayoutdev.c
@@ -185,6 +185,7 @@ nfs4_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds)
        if (status)
                goto out_put;
 
+       smp_wmb();
        ds->ds_clp = clp;
        dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
 out:
@@ -809,6 +810,7 @@ nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
                filelayout_mark_devid_invalid(devid);
                goto out;
        }
+       smp_rmb();
        if (ds->ds_clp)
                goto out_test_devid;