[PATCH REGRESSION 4.12-rc1] ovl: add missing CONFIG_EXPORTFS dependency

[Ralph Sennhauser]

The source files namei.c and copy_up.c in overlayfs new use
exportfs_decode_fh which depends on CONFIG_EXPORTFS being set. Select it
in Kconfig.

Fixes: a9d019573e88 ("ovl: lookup non-dir copy-up-origin by file handle")
Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up")
Signed-off-by: Ralph Sennhauser <ralph.sennhauser@xxxxxxxxx>
---
 fs/overlayfs/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 0daac51..c0c9683 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -1,5 +1,6 @@
 config OVERLAY_FS
 	tristate "Overlay filesystem support"
+	select EXPORTFS
 	help
 	  An overlay filesystem combines two filesystems - an 'upper' filesystem
 	  and a 'lower' filesystem.  When a name exists in both filesystems, the
-- 
2.10.2