Root/fs/jffs2/Kconfig

1config JFFS2_FS
2    tristate "Journalling Flash File System v2 (JFFS2) support"
3    select CRC32
4    depends on MTD
5    help
6      JFFS2 is the second generation of the Journalling Flash File System
7      for use on diskless embedded devices. It provides improved wear
8      levelling, compression and support for hard links. You cannot use
9      this on normal block devices, only on 'MTD' devices.
10
11      Further information on the design and implementation of JFFS2 is
12      available at <http://sources.redhat.com/jffs2/>.
13
14config JFFS2_FS_DEBUG
15    int "JFFS2 debugging verbosity (0 = quiet, 2 = noisy)"
16    depends on JFFS2_FS
17    default "0"
18    help
19      This controls the amount of debugging messages produced by the JFFS2
20      code. Set it to zero for use in production systems. For evaluation,
21      testing and debugging, it's advisable to set it to one. This will
22      enable a few assertions and will print debugging messages at the
23      KERN_DEBUG loglevel, where they won't normally be visible. Level 2
24      is unlikely to be useful - it enables extra debugging in certain
25      areas which at one point needed debugging, but when the bugs were
26      located and fixed, the detailed messages were relegated to level 2.
27
28      If reporting bugs, please try to have available a full dump of the
29      messages at debug level 1 while the misbehaviour was occurring.
30
31config JFFS2_FS_WRITEBUFFER
32    bool "JFFS2 write-buffering support"
33    depends on JFFS2_FS
34    default y
35    help
36      This enables the write-buffering support in JFFS2.
37
38      This functionality is required to support JFFS2 on the following
39      types of flash devices:
40        - NAND flash
41        - NOR flash with transparent ECC
42        - DataFlash
43
44config JFFS2_FS_WBUF_VERIFY
45    bool "Verify JFFS2 write-buffer reads"
46    depends on JFFS2_FS_WRITEBUFFER
47    default n
48    help
49      This causes JFFS2 to read back every page written through the
50      write-buffer, and check for errors.
51
52config JFFS2_SUMMARY
53    bool "JFFS2 summary support (EXPERIMENTAL)"
54    depends on JFFS2_FS && EXPERIMENTAL
55    default n
56    help
57      This feature makes it possible to use summary information
58      for faster filesystem mount.
59
60      The summary information can be inserted into a filesystem image
61      by the utility 'sumtool'.
62
63      If unsure, say 'N'.
64
65config JFFS2_FS_XATTR
66    bool "JFFS2 XATTR support (EXPERIMENTAL)"
67    depends on JFFS2_FS && EXPERIMENTAL
68    default n
69    help
70      Extended attributes are name:value pairs associated with inodes by
71      the kernel or by users (see the attr(5) manual page, or visit
72      <http://acl.bestbits.at/> for details).
73
74      If unsure, say N.
75
76config JFFS2_FS_POSIX_ACL
77    bool "JFFS2 POSIX Access Control Lists"
78    depends on JFFS2_FS_XATTR
79    default y
80    select FS_POSIX_ACL
81    help
82      Posix Access Control Lists (ACLs) support permissions for users and
83      groups beyond the owner/group/world scheme.
84
85      To learn more about Access Control Lists, visit the Posix ACLs for
86      Linux website <http://acl.bestbits.at/>.
87
88      If you don't know what Access Control Lists are, say N
89
90config JFFS2_FS_SECURITY
91    bool "JFFS2 Security Labels"
92    depends on JFFS2_FS_XATTR
93    default y
94    help
95      Security labels support alternative access control models
96      implemented by security modules like SELinux. This option
97      enables an extended attribute handler for file security
98      labels in the jffs2 filesystem.
99
100      If you are not using a security module that requires using
101      extended attributes for file security labels, say N.
102
103config JFFS2_COMPRESSION_OPTIONS
104    bool "Advanced compression options for JFFS2"
105    depends on JFFS2_FS
106    default n
107    help
108      Enabling this option allows you to explicitly choose which
109      compression modules, if any, are enabled in JFFS2. Removing
110      compressors can mean you cannot read existing file systems,
111      and enabling experimental compressors can mean that you
112      write a file system which cannot be read by a standard kernel.
113
114      If unsure, you should _definitely_ say 'N'.
115
116config JFFS2_ZLIB
117    bool "JFFS2 ZLIB compression support" if JFFS2_COMPRESSION_OPTIONS
118    select ZLIB_INFLATE
119    select ZLIB_DEFLATE
120    depends on JFFS2_FS
121    default y
122    help
123      Zlib is designed to be a free, general-purpose, legally unencumbered,
124      lossless data-compression library for use on virtually any computer
125      hardware and operating system. See <http://www.gzip.org/zlib/> for
126      further information.
127
128      Say 'Y' if unsure.
129
130config JFFS2_LZO
131    bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS
132    select LZO_COMPRESS
133    select LZO_DECOMPRESS
134    depends on JFFS2_FS
135    default n
136    help
137      minilzo-based compression. Generally works better than Zlib.
138
139      This feature was added in July, 2007. Say 'N' if you need
140      compatibility with older bootloaders or kernels.
141
142config JFFS2_RTIME
143    bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS
144    depends on JFFS2_FS
145    default y
146    help
147      Rtime does manage to recompress already-compressed data. Say 'Y' if unsure.
148
149config JFFS2_RUBIN
150    bool "JFFS2 RUBIN compression support" if JFFS2_COMPRESSION_OPTIONS
151    depends on JFFS2_FS
152    default n
153    help
154      RUBINMIPS and DYNRUBIN compressors. Say 'N' if unsure.
155
156choice
157    prompt "JFFS2 default compression mode" if JFFS2_COMPRESSION_OPTIONS
158    default JFFS2_CMODE_PRIORITY
159    depends on JFFS2_FS
160    help
161      You can set here the default compression mode of JFFS2 from
162      the available compression modes. Don't touch if unsure.
163
164config JFFS2_CMODE_NONE
165    bool "no compression"
166    help
167      Uses no compression.
168
169config JFFS2_CMODE_PRIORITY
170    bool "priority"
171    help
172      Tries the compressors in a predefined order and chooses the first
173      successful one.
174
175config JFFS2_CMODE_SIZE
176    bool "size (EXPERIMENTAL)"
177    help
178      Tries all compressors and chooses the one which has the smallest
179      result.
180
181config JFFS2_CMODE_FAVOURLZO
182    bool "Favour LZO"
183    help
184      Tries all compressors and chooses the one which has the smallest
185      result but gives some preference to LZO (which has faster
186      decompression) at the expense of size.
187
188endchoice
189

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