NFSv4.1: Don't cache deviceids that have no notifications

The spec says that once all layouts that reference a given deviceid
have been returned, then we are only allowed to continue to cache
the deviceid if the metadata server supports notifications.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ba8b2b5e98a1..9ff8c63c9cac 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7962,6 +7962,8 @@ _nfs4_proc_getdeviceinfo(struct nfs_server *server,
         status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
         if (res.notification & ~args.notify_types)
                 dprintk("%s: unsupported notification\n", __func__);
+        if (res.notification != args.notify_types)
+                pdev->nocache = 1;
 
         dprintk("<-- %s status=%d\n", __func__, status);