From 36cd95dfa1ed76b59e2dcaafaa89c5479cec32b5 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi <mszeredi@redhat.com> Date: Wed, 7 Mar 2018 11:47:15 +0100 Subject: [PATCH] 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> --- fs/overlayfs/Kconfig | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig index 406e72de88f6f8..ce6ff5a0a6e4e8 100644 --- a/fs/overlayfs/Kconfig +++ b/fs/overlayfs/Kconfig @@ -24,6 +24,8 @@ config OVERLAY_FS_REDIRECT_DIR 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 @@ config OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW 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 @@ config OVERLAY_FS_INDEX 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 @@ config OVERLAY_FS_NFS_EXPORT 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. -- GitLab