1MKFS.JFFS2(1) General Commands Manual MKFS.JFFS2(1)
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6 mkfs.jffs2 - Create a JFFS2 file system image from directory
7
9 mkfs.jffs2 [ -p,--pad[=SIZE] ] [ -r,-d,--root directory ] [ -s,--page‐
10 size=SIZE ] [ -e,--eraseblock=SIZE ] [ -c,--cleanmarker=SIZE ] [
11 -n,--no-cleanmarkers ] [ -o,--output image.jffs2 ] [ -l,--little-endian
12 ] [ -b,--big-endian ] [ -D,--devtable=FILE ] [ -f,--faketime ] [
13 -q,--squash ] [ -U,--squash-uids ] [ -P,--squash-perms ] [ --with-xattr
14 ] [ --with-selinux ] [ --with-posix-acl ] [ -m,--compression-mode=MODE
15 ] [ -x,--disable-compressor=NAME ] [ -X,--enable-compressor=NAME ] [
16 -y,--compressor-priority=PRIORITY:NAME ] [ -L,--list-compressors ] [
17 -t,--test-compression ] [ -h,--help ] [ -v,--verbose ] [ -V,--version ]
18 [ -i,--incremental image.jffs2 ]
19
22 The program mkfs.jffs2 creates a JFFS2 (Second Journalling Flash File
23 System) file system image and writes the resulting image to the file
24 specified by the -o option or by default to the standard output, unless
25 the standard output is a terminal device in which case mkfs.jffs2 will
26 abort.
27 The file system image is created using the files and directories con‐
29 tained in the directory specified by the option -r or the present
30 directory, if the -r option is not specified.
31 Each block of the files to be placed into the file system image are
33 compressed using one of the avaiable compressors depending on the
34 selected compression mode.
35 File systems are created with the same endianness as the host, unless
37 the -b or -l options are specified. JFFS2 driver in the 2.4 Linux ker‐
38 nel only supported images having the same endianness as the CPU. As of
39 2.5.48, the kernel can be changed with a #define to accept images of
40 the non-native endianness. Full bi-endian support in the kernel is not
41 planned.
42 It is unlikely that JFFS2 images are useful except in conjuction with
44 the MTD (Memory Technology Device) drivers in the Linux kernel, since
45 the JFFS2 file system driver in the kernel requires MTD devices.
46
48 Options that take SIZE arguments can be specified as either decimal
49 (e.g., 65536), octal (0200000), or hexidecimal (0x1000).
50 -p, --pad[=SIZE]
52 Pad output to SIZE bytes with 0xFF. If SIZE is not specified,
53 the output is padded to the end of the final erase block.
54 -r, -d, --root=DIR
56 Build file system from directory DIR. The default is the cur‐
57 rent directory.
58 -s, --pagesize=SIZE
60 Use page size SIZE. The default is 4 KiB. This size is the
61 maximum size of a data node.
62 -e, --eraseblock=SIZE
64 Use erase block size SIZE. The default is 64 KiB. If you use a
65 erase block size different than the erase block size of the tar‐
66 get MTD device, JFFS2 may not perform optimally. If the SIZE
67 specified is below 4096, the units are assumed to be KiB.
68 -c, --cleanmarker=SIZE
70 Write ´CLEANMARKER´ nodes with the size specified. It is not
71 normally appropriate to specify a size other than the default 12
72 bytes.
73 -n, --no-cleanmarkers
75 Do not write ´CLEANMARKER´ nodes to the beginning of each erase
76 block. This option can be useful for creating JFFS2 images for
77 use on NAND flash, and for creating images which are to be used
78 on a variety of hardware with differing eraseblock sizes.
79 -o, --output=FILE
81 Write JFFS2 image to file FILE. Default is the standard output.
82 -l, --little-endian
84 Create a little-endian JFFS2 image. Default is to make an image
85 with the same endianness as the host.
86 -b, --big-endian
88 Create a big-endian JFFS2 image. Default is to make an image
89 with the same endianness as the host.
90 -D, --devtable=FILE
92 Use the named FILE as a device table file, for including devices
93 and changing permissions in the created image when the user does
94 not have appropriate permissions to create them on the file sys‐
95 tem used as source.
96 -f, --faketime
98 Change all file timestamps to ´0´ for regression testing.
99 -q, --squash
101 Squash permissions and owners, making all files be owned by root
102 and removing write permission for ´group´ and ´other´.
103 -U, --squash-uids
105 Squash owners making all files be owned by root.
106 -P, --squash-perms
108 Squash permissions, removing write permission for ´group´ and
109 ´other´.
110 --with-xattr
112 Enables xattr, stuff all xattr entries into jffs2 image file.
113 --with-selinux
115 Enables xattr, stuff only SELinux Labels into jffs2 image file.
116 --with-posix-acl
118 Enable xattr, stuff only POSIX ACL entries into jffs2 image
119 file.
120 -m, --compression-mode=MODE
122 Set the default compression mode. The default mode is priority
123 which tries the compressors in a predefinied order and chooses
124 the first successful one. The alternatives are: none (mkfs will
125 not compress) and size (mkfs will try all compressor and chooses
126 the one which have the smallest result).
127 -x, --disable-compressor=NAME
129 Disable a compressor. Use -L to see the list of the avaiable
130 compressors and their default states.
131 -X, --enable-compressor=NAME
133 Enable a compressor. Use -L to see the list of the avaiable com‐
134 pressors and their default states.
135 -y, --compressor-priority=PRIORITY:NAME
137 Set the priority of a compressor. Use -L to see the list of the
138 avaiable compressors and their default priority. Priorities are
139 used by priority compression mode.
140 -L, --list-compressors
142 Show the list of the avaiable compressors and their states.
143 -t, --test-compression
145 Call decompress after every compress - and compare the result
146 with the original data -, and some other check.
147 -h, --help
149 Display help text.
150 -v, --verbose
152 Verbose operation.
153 -V, --version
155 Display version information.
156 -i, --incremental=FILE
158 Generate an appendage image for FILE. If FILE is written to
159 flash and flash is appended with the output, then it seems as if
160 it was one thing.
161
164 The format and grammar of the device table file does not allow it to
165 create symbolic links when the symbolic links are not already present
166 in the root working directory.
167 However, symbolic links may be specified in the device table file using
169 the l type for the purposes of setting their permissions and ownership.
170
172 JFFS2 limits device major and minor numbers to 8 bits each. Some con‐
173 sider this a bug.
174 mkfs.jffs2 does not properly handle hard links in the input directory
176 structure. Currently, hard linked files will be expanded to multiple
177 identical files in the output image.
178
180 David Woodhouse
181 Manual page written by David Schleef <ds@schleef.org>
182
184 mkfs(8), mkfs.jffs(1), fakeroot(1)
185 MKFS.JFFS2(1)