# 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
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