fs/overlayfs/Kconfig

Source file repositories/reference/linux-study-clean/fs/overlayfs/Kconfig

File Facts

System
Linux kernel
Corpus path
fs/overlayfs/Kconfig
Extension
[no extension]
Size
5224 bytes
Lines
137
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: build/configuration rule
Status
atlas-only

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

# SPDX-License-Identifier: GPL-2.0-only
config OVERLAY_FS
	tristate "Overlay filesystem support"
	select FS_STACK
	select EXPORTFS
	help
	  An overlay filesystem combines two filesystems - an 'upper' filesystem
	  and a 'lower' filesystem.  When a name exists in both filesystems, the
	  object in the 'upper' filesystem is visible while the object in the
	  'lower' filesystem is either hidden or, in the case of directories,
	  merged with the 'upper' object.

	  For more information see Documentation/filesystems/overlayfs.rst

config OVERLAY_FS_REDIRECT_DIR
	bool "Overlayfs: turn on redirect directory feature by default"
	depends on OVERLAY_FS
	help
	  If this config option is enabled then overlay filesystems will use
	  redirects when renaming directories by default.  In this case it is
	  still possible to turn off redirects globally with the
	  "redirect_dir=off" module option or on a filesystem instance basis
	  with the "redirect_dir=off" mount option.

	  Note, that redirects are not backward compatible.  That is, mounting
	  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.rst

	  If unsure, say Y.

config OVERLAY_FS_INDEX
	bool "Overlayfs: turn on inodes index feature by default"
	depends on OVERLAY_FS
	help
	  If this config option is enabled then overlay filesystems will use
	  the index directory to map lower inodes to upper inodes by default.
	  In this case it is still possible to turn off index globally with the
	  "index=off" module option or on a filesystem instance basis with the
	  "index=off" mount option.

	  The inodes index feature prevents breaking of lower hardlinks on copy
	  up.

	  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
	depends on !OVERLAY_FS_METACOPY
	help

Annotation

Implementation Notes