NFSv4.2: Change the default KConfig value for READ_PLUS

Now that we've worked out performance issues and have a server patch
addressing the failed xfstests, we can safely enable this feature by
default.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Author: amschuma-ntap

fs/nfs/Kconfig

@@ -209,8 +209,8 @@ config NFS_DISABLE_UDP_SUPPORT
 config NFS_V4_2_READ_PLUS
 	bool "NFS: Enable support for the NFSv4.2 READ_PLUS operation"
 	depends on NFS_V4_2
-	default n
+	default y
 	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.
+	 Choose Y here to enable the use of READ_PLUS over NFS v4.2. READ_PLUS
+	 attempts to improve read performance by compressing out sparse holes
+	 in the file contents.