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 ]
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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 available 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. Set according to target system's
62 memory management page size (NOTE: this is NOT related to NAND
63 page size).
64 -e, --eraseblock=SIZE
66 Use erase block size SIZE. The default is 64 KiB. If you use a
67 erase block size different than the erase block size of the tar‐
68 get MTD device, JFFS2 may not perform optimally. If the SIZE
69 specified is below 4096, the units are assumed to be KiB.
70 -c, --cleanmarker=SIZE
72 Write ´CLEANMARKER´ nodes with the size specified. It is not
73 normally appropriate to specify a size other than the default 12
74 bytes.
75 -n, --no-cleanmarkers
77 Do not write ´CLEANMARKER´ nodes to the beginning of each erase
78 block. This option can be useful for creating JFFS2 images for
79 use on NAND flash, and for creating images which are to be used
80 on a variety of hardware with differing eraseblock sizes.
81 -o, --output=FILE
83 Write JFFS2 image to file FILE. Default is the standard output.
84 -l, --little-endian
86 Create a little-endian JFFS2 image. Default is to make an image
87 with the same endianness as the host.
88 -b, --big-endian
90 Create a big-endian JFFS2 image. Default is to make an image
91 with the same endianness as the host.
92 -D, --devtable=FILE
94 Use the named FILE as a device table file, for including devices
95 and changing permissions in the created image when the user does
96 not have appropriate permissions to create them on the file sys‐
97 tem used as source.
98 -f, --faketime
100 Change all file timestamps to ´0´ for regression testing.
101 -q, --squash
103 Squash permissions and owners, making all files be owned by root
104 and removing write permission for ´group´ and ´other´.
105 -U, --squash-uids
107 Squash owners making all files be owned by root.
108 -P, --squash-perms
110 Squash permissions, removing write permission for ´group´ and
111 ´other´.
112 --with-xattr
114 Enables xattr, stuff all xattr entries into jffs2 image file.
115 --with-selinux
117 Enables xattr, stuff only SELinux Labels into jffs2 image file.
118 --with-posix-acl
120 Enable xattr, stuff only POSIX ACL entries into jffs2 image
121 file.
122 -m, --compression-mode=MODE
124 Set the default compression mode. The default mode is priority
125 which tries the compressors in a predefinied order and chooses
126 the first successful one. The alternatives are: none (mkfs will
127 not compress) and size (mkfs will try all compressor and chooses
128 the one which have the smallest result).
129 -x, --disable-compressor=NAME
131 Disable a compressor. Use -L to see the list of the available
132 compressors and their default states.
133 -X, --enable-compressor=NAME
135 Enable a compressor. Use -L to see the list of the available
136 compressors and their default states.
137 -y, --compressor-priority=PRIORITY:NAME
139 Set the priority of a compressor. Use -L to see the list of the
140 available compressors and their default priority. Priorities
141 are used by priority compression mode.
142 -L, --list-compressors
144 Show the list of the available compressors and their states.
145 -t, --test-compression
147 Call decompress after every compress - and compare the result
148 with the original data -, and some other check.
149 -h, --help
151 Display help text.
152 -v, --verbose
154 Verbose operation.
155 -V, --version
157 Display version information.
158 -i, --incremental=FILE
160 Generate an appendage image for FILE. If FILE is written to
161 flash and flash is appended with the output, then it seems as if
162 it was one thing.
163
166 The format and grammar of the device table file does not allow it to
167 create symbolic links when the symbolic links are not already present
168 in the root working directory.
169 However, symbolic links may be specified in the device table file using
171 the l type for the purposes of setting their permissions and ownership.
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174 JFFS2 limits device major and minor numbers to 8 bits each. Some con‐
175 sider this a bug.
176 mkfs.jffs2 does not properly handle hard links in the input directory
178 structure. Currently, hard linked files will be expanded to multiple
179 identical files in the output image.
180
182 David Woodhouse
183 Manual page written by David Schleef <ds@schleef.org>
184
186 mkfs(8), mkfs.jffs(1), fakeroot(1)
187 MKFS.JFFS2(1)