NFS: Disable READ_PLUS by default

We've been seeing failures with xfstests generic/091 and generic/263
when using READ_PLUS. I've made some progress on these issues, and the
tests fail later on but still don't pass. Let's disable READ_PLUS by
default until we can work out what is going on.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 88e1763..e2a488d 100644 (file)
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -205,3 +205,12 @@ config NFS_DISABLE_UDP_SUPPORT
         Choose Y here to disable the use of NFS over UDP. NFS over UDP
         on modern networks (1Gb+) can lead to data corruption caused by
         fragmentation during high loads.
+
+config NFS_V4_2_READ_PLUS
+       bool "NFS: Enable support for the NFSv4.2 READ_PLUS operation"
+       depends on NFS_V4_2
+       default n
+       help
+        This is intended for developers only. The READ_PLUS operation has
+        been shown to have issues under specific conditions and should not
+        be used in production.

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9e0ca9b..e894686 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5309,7 +5309,7 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr)
                                    nfs4_read_done_cb(task, hdr);
 }
 
-#ifdef CONFIG_NFS_V4_2
+#if defined CONFIG_NFS_V4_2 && defined CONFIG_NFS_V4_2_READ_PLUS
 static void nfs42_read_plus_support(struct nfs_server *server, struct rpc_message *msg)
 {
        if (server->caps & NFS_CAP_READ_PLUS)