From: Benjamin Coddington <bcodding@redhat.com>
Date: Tue, 30 Aug 2016 13:20:32 +0000 (-0400)
Subject: NFS4: Avoid migration loops
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=52442f9b11b7e5d4a38d99143011831fd171f8d9;p=linux-beck.git

NFS4: Avoid migration loops

If a server returns itself as a location while migrating, the client may
end up getting stuck attempting to migrate twice to the same server.  Catch
this by checking if the nfs_client found is the same as the existing
client.  For the other two callers to nfs4_set_client, the nfs_client will
always be ERR_PTR(-EINVAL).

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 8d7d08d4f95f..cd3b7cfdde16 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -817,6 +817,11 @@ static int nfs4_set_client(struct nfs_server *server,
 		goto error;
 	}
 
+	if (server->nfs_client == clp) {
+		error = -ELOOP;
+		goto error;
+	}
+
 	/*
 	 * Query for the lease time on clientid setup or renewal
 	 *