# SPDX-License-Identifier: GPL-2.0-only
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config JFFS2_FS
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tristate "Journalling Flash File System v2 (JFFS2) support"
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select CRC32
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depends on MTD
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help
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JFFS2 is the second generation of the Journalling Flash File System
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for use on diskless embedded devices. It provides improved wear
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levelling, compression and support for hard links. You cannot use
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this on normal block devices, only on 'MTD' devices.
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Further information on the design and implementation of JFFS2 is
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available at <http://sources.redhat.com/jffs2/>.
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config JFFS2_FS_DEBUG
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int "JFFS2 debugging verbosity (0 = quiet, 2 = noisy)"
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depends on JFFS2_FS
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default "0"
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help
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This controls the amount of debugging messages produced by the JFFS2
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code. Set it to zero for use in production systems. For evaluation,
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testing and debugging, it's advisable to set it to one. This will
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enable a few assertions and will print debugging messages at the
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KERN_DEBUG loglevel, where they won't normally be visible. Level 2
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is unlikely to be useful - it enables extra debugging in certain
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areas which at one point needed debugging, but when the bugs were
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located and fixed, the detailed messages were relegated to level 2.
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If reporting bugs, please try to have available a full dump of the
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messages at debug level 1 while the misbehaviour was occurring.
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config JFFS2_FS_WRITEBUFFER
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bool "JFFS2 write-buffering support"
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depends on JFFS2_FS
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default y
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help
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This enables the write-buffering support in JFFS2.
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This functionality is required to support JFFS2 on the following
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types of flash devices:
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- NAND flash
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- NOR flash with transparent ECC
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- DataFlash
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config JFFS2_FS_WBUF_VERIFY
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bool "Verify JFFS2 write-buffer reads"
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depends on JFFS2_FS_WRITEBUFFER
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default n
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help
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This causes JFFS2 to read back every page written through the
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write-buffer, and check for errors.
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config JFFS2_SUMMARY
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bool "JFFS2 summary support"
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depends on JFFS2_FS
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default n
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help
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This feature makes it possible to use summary information
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for faster filesystem mount.
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The summary information can be inserted into a filesystem image
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by the utility 'sumtool'.
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If unsure, say 'N'.
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config JFFS2_FS_XATTR
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bool "JFFS2 XATTR support"
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depends on JFFS2_FS
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default n
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help
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Extended attributes are name:value pairs associated with inodes by
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the kernel or by users (see the attr(5) manual page for details).
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If unsure, say N.
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config JFFS2_FS_POSIX_ACL
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bool "JFFS2 POSIX Access Control Lists"
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depends on JFFS2_FS_XATTR
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default y
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select FS_POSIX_ACL
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help
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Posix Access Control Lists (ACLs) support permissions for users and
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groups beyond the owner/group/world scheme.
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If you don't know what Access Control Lists are, say N
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config JFFS2_FS_SECURITY
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bool "JFFS2 Security Labels"
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depends on JFFS2_FS_XATTR
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default y
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help
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Security labels support alternative access control models
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implemented by security modules like SELinux. This option
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enables an extended attribute handler for file security
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labels in the jffs2 filesystem.
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If you are not using a security module that requires using
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extended attributes for file security labels, say N.
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config JFFS2_COMPRESSION_OPTIONS
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bool "Advanced compression options for JFFS2"
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depends on JFFS2_FS
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default n
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help
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Enabling this option allows you to explicitly choose which
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compression modules, if any, are enabled in JFFS2. Removing
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compressors can mean you cannot read existing file systems,
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and enabling experimental compressors can mean that you
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write a file system which cannot be read by a standard kernel.
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If unsure, you should _definitely_ say 'N'.
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config JFFS2_ZLIB
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bool "JFFS2 ZLIB compression support" if JFFS2_COMPRESSION_OPTIONS
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select ZLIB_INFLATE
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select ZLIB_DEFLATE
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depends on JFFS2_FS
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default y
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help
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Zlib is designed to be a free, general-purpose, legally unencumbered,
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lossless data-compression library for use on virtually any computer
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hardware and operating system. See <http://www.gzip.org/zlib/> for
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further information.
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Say 'Y' if unsure.
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config JFFS2_LZO
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bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS
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select LZO_COMPRESS
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select LZO_DECOMPRESS
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depends on JFFS2_FS
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default n
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help
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minilzo-based compression. Generally works better than Zlib.
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This feature was added in July, 2007. Say 'N' if you need
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compatibility with older bootloaders or kernels.
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config JFFS2_RTIME
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bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS
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depends on JFFS2_FS
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default y
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help
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Rtime does manage to recompress already-compressed data. Say 'Y' if unsure.
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config JFFS2_RUBIN
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bool "JFFS2 RUBIN compression support" if JFFS2_COMPRESSION_OPTIONS
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depends on JFFS2_FS
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default n
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help
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RUBINMIPS and DYNRUBIN compressors. Say 'N' if unsure.
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choice
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prompt "JFFS2 default compression mode" if JFFS2_COMPRESSION_OPTIONS
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default JFFS2_CMODE_PRIORITY
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depends on JFFS2_FS
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help
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You can set here the default compression mode of JFFS2 from
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the available compression modes. Don't touch if unsure.
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config JFFS2_CMODE_NONE
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bool "no compression"
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help
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Uses no compression.
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config JFFS2_CMODE_PRIORITY
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bool "priority"
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help
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Tries the compressors in a predefined order and chooses the first
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successful one.
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config JFFS2_CMODE_SIZE
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bool "size"
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help
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Tries all compressors and chooses the one which has the smallest
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result.
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config JFFS2_CMODE_FAVOURLZO
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bool "Favour LZO"
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help
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Tries all compressors and chooses the one which has the smallest
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result but gives some preference to LZO (which has faster
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decompression) at the expense of size.
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endchoice
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