ovl: update Kconfig texts
Add some hints about overlayfs kernel config options.
Enabling NFS export by default is especially recommended against, as it
incurs a performance penalty even if the filesystem is not actually
exported.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 406e72d..ce6ff5a 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -24,6 +24,8 @@
an overlay which has redirects on a kernel that doesn't support this
feature will have unexpected results.
+ If unsure, say N.
+
config OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW
bool "Overlayfs: follow redirects even if redirects are turned off"
default y
@@ -32,8 +34,13 @@
Disable this to get a possibly more secure configuration, but that
might not be backward compatible with previous kernels.
+ If backward compatibility is not an issue, then it is safe and
+ recommended to say N here.
+
For more information, see Documentation/filesystems/overlayfs.txt
+ If unsure, say Y.
+
config OVERLAY_FS_INDEX
bool "Overlayfs: turn on inodes index feature by default"
depends on OVERLAY_FS
@@ -51,6 +58,8 @@
That is, mounting an overlay which has an inodes index on a kernel
that doesn't support this feature will have unexpected results.
+ If unsure, say N.
+
config OVERLAY_FS_NFS_EXPORT
bool "Overlayfs: turn on NFS export feature by default"
depends on OVERLAY_FS
@@ -72,3 +81,8 @@
Note, that the NFS export feature is not backward compatible.
That is, mounting an overlay which has a full index on a kernel
that doesn't support this feature will have unexpected results.
+
+ Most users should say N here and enable this feature on a case-by-
+ case basis with the "nfs_export=on" mount option.
+
+ Say N unless you fully understand the consequences.