pnfs/blocklayout: require 64-bit sector_t

The blocklayout code does not compile cleanly for a 32-bit sector_t,
and also has no reliable checks for devices sizes, which makes it
unsafe to use with a kernel that doesn't support large block devices.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 5c83746a ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/Kconfig

@@ -121,6 +121,7 @@ config PNFS_FILE_LAYOUT
 config PNFS_BLOCK
 	tristate
 	depends on NFS_V4_1 && BLK_DEV_DM
+	depends on 64BIT || LBDAF
 	default NFS_V4
 
 config PNFS_FLEXFILE_LAYOUT