diff options
Diffstat (limited to 'fs/overlayfs/Kconfig')
| -rw-r--r-- | fs/overlayfs/Kconfig | 55 |
1 files changed, 49 insertions, 6 deletions
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig index cbfc196e5dc5..ce6ff5a0a6e4 100644 --- a/fs/overlayfs/Kconfig +++ b/fs/overlayfs/Kconfig @@ -24,6 +24,23 @@ 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 + depends on OVERLAY_FS + help + 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 @@ -37,9 +54,35 @@ config OVERLAY_FS_INDEX The inodes index feature prevents breaking of lower hardlinks on copy up. - Note, that the inodes index feature is read-only backward compatible. - That is, mounting an overlay which has an index dir on a kernel that - doesn't support this feature read-only, will not have any negative - outcomes. However, mounting the same overlay with an old kernel - read-write and then mounting it again with a new kernel, will have - unexpected results. + Note, that the inodes index feature is not backward compatible. + 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 + depends on OVERLAY_FS_INDEX + help + If this config option is enabled then overlay filesystems will use + the inodes index dir to decode overlay NFS file handles by default. + In this case, it is still possible to turn off NFS export support + globally with the "nfs_export=off" module option or on a filesystem + instance basis with the "nfs_export=off" mount option. + + The NFS export feature creates an index on copy up of every file and + directory. This full index is used to detect overlay filesystems + inconsistencies on lookup, like redirect from multiple upper dirs to + the same lower dir. The full index may incur some overhead on mount + time, especially when verifying that directory file handles are not + stale. + + 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. |