# SPDX-License-Identifier: GPL-2.0-only

config JFFS2_FS

tristate "Journalling Flash File System v2 (JFFS2) support"

select CRC32

depends on MTD

help

JFFS2 is the second generation of the Journalling Flash File System

for use on diskless embedded devices. It provides improved wear

levelling, compression and support for hard links. You cannot use

this on normal block devices, only on 'MTD' devices.

Further information on the design and implementation of JFFS2 is

available at <http://sources.redhat.com/jffs2/>.

config JFFS2_FS_DEBUG

int "JFFS2 debugging verbosity (0 = quiet, 2 = noisy)"

depends on JFFS2_FS

default "0"

help

This controls the amount of debugging messages produced by the JFFS2

code. Set it to zero for use in production systems. For evaluation,

testing and debugging, it's advisable to set it to one. This will

enable a few assertions and will print debugging messages at the

KERN_DEBUG loglevel, where they won't normally be visible. Level 2

is unlikely to be useful - it enables extra debugging in certain

areas which at one point needed debugging, but when the bugs were

located and fixed, the detailed messages were relegated to level 2.

If reporting bugs, please try to have available a full dump of the

messages at debug level 1 while the misbehaviour was occurring.

config JFFS2_FS_WRITEBUFFER

bool "JFFS2 write-buffering support"

depends on JFFS2_FS

default y

help

This enables the write-buffering support in JFFS2.

This functionality is required to support JFFS2 on the following

types of flash devices:

- NAND flash

- NOR flash with transparent ECC

- DataFlash

config JFFS2_FS_WBUF_VERIFY

bool "Verify JFFS2 write-buffer reads"

depends on JFFS2_FS_WRITEBUFFER

default n

help

This causes JFFS2 to read back every page written through the

write-buffer, and check for errors.

config JFFS2_SUMMARY

bool "JFFS2 summary support"

depends on JFFS2_FS

default n

help

This feature makes it possible to use summary information

for faster filesystem mount.

The summary information can be inserted into a filesystem image

by the utility 'sumtool'.

If unsure, say 'N'.

config JFFS2_FS_XATTR

bool "JFFS2 XATTR support"

depends on JFFS2_FS

default n

help

Extended attributes are name:value pairs associated with inodes by

the kernel or by users (see the attr(5) manual page for details).

If unsure, say N.

config JFFS2_FS_POSIX_ACL

bool "JFFS2 POSIX Access Control Lists"

depends on JFFS2_FS_XATTR

default y

select FS_POSIX_ACL

help

Posix Access Control Lists (ACLs) support permissions for users and

groups beyond the owner/group/world scheme.

If you don't know what Access Control Lists are, say N

config JFFS2_FS_SECURITY

bool "JFFS2 Security Labels"

depends on JFFS2_FS_XATTR

default y

help

Security labels support alternative access control models

implemented by security modules like SELinux. This option

enables an extended attribute handler for file security

labels in the jffs2 filesystem.

If you are not using a security module that requires using

extended attributes for file security labels, say N.

config JFFS2_COMPRESSION_OPTIONS

bool "Advanced compression options for JFFS2"

depends on JFFS2_FS

default n

help

Enabling this option allows you to explicitly choose which

compression modules, if any, are enabled in JFFS2. Removing

compressors can mean you cannot read existing file systems,

and enabling experimental compressors can mean that you

write a file system which cannot be read by a standard kernel.

If unsure, you should _definitely_ say 'N'.

config JFFS2_ZLIB

bool "JFFS2 ZLIB compression support" if JFFS2_COMPRESSION_OPTIONS

select ZLIB_INFLATE

select ZLIB_DEFLATE

depends on JFFS2_FS

default y

help

Zlib is designed to be a free, general-purpose, legally unencumbered,

lossless data-compression library for use on virtually any computer

hardware and operating system. See <http://www.gzip.org/zlib/> for

further information.

Say 'Y' if unsure.

config JFFS2_LZO

bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS

select LZO_COMPRESS

select LZO_DECOMPRESS

depends on JFFS2_FS

default n

help

minilzo-based compression. Generally works better than Zlib.

This feature was added in July, 2007. Say 'N' if you need

compatibility with older bootloaders or kernels.

config JFFS2_RTIME

bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS

depends on JFFS2_FS

default y

help

Rtime does manage to recompress already-compressed data. Say 'Y' if unsure.

config JFFS2_RUBIN

bool "JFFS2 RUBIN compression support" if JFFS2_COMPRESSION_OPTIONS

depends on JFFS2_FS

default n

help

RUBINMIPS and DYNRUBIN compressors. Say 'N' if unsure.

choice

prompt "JFFS2 default compression mode"

default JFFS2_CMODE_PRIORITY

depends on JFFS2_COMPRESSION_OPTIONS

depends on JFFS2_FS

help

You can set here the default compression mode of JFFS2 from

the available compression modes. Don't touch if unsure.

config JFFS2_CMODE_NONE

bool "no compression"

help

Uses no compression.

config JFFS2_CMODE_PRIORITY

bool "priority"

help

Tries the compressors in a predefined order and chooses the first

successful one.

config JFFS2_CMODE_SIZE

bool "size"

help

Tries all compressors and chooses the one which has the smallest

result.

config JFFS2_CMODE_FAVOURLZO

bool "Favour LZO"

help

Tries all compressors and chooses the one which has the smallest

result but gives some preference to LZO (which has faster

decompression) at the expense of size.

endchoice