From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Thu, 26 Sep 2013 18:32:56 +0000 (-0400)
Subject: NFSv4.1: Ensure memory ordering between nfs4_ds_connect and nfs4_fl_prepare_ds
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=acd65e5bc1986d0089efec3fe63e52ea0c406d6d;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

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 cd3aef571c34..c7c295e556ed 100644
--- 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;