jffs2常见问题

Question1：JFFS2 error: (1) jffs2_build_inode_pass1: child dir "alsa" (ino #1159) of dir ino #1074 appears to be a hard link

JFFS2 error: (1) jffs2_build_inode_pass1: child dir "l" (ino #1170) of dir ino #1075 appears to be a hard link

原由: flash没有erase彻底.

VFS: Mounted root (jffs2 filesystem) on device 31:1.

Freeing init memory: 136K

JFFS2 notice: (1) check_node_data: wrong data CRC in data node at 0x0f0a7f78: read 0x4462b066, calculated 0x48ea177f.

JFFS2 error: (488) jffs2_do_read_inode_internal: Argh. Special inode #139 with mode 0x61b0 had more than one node

iget() failed for ino #139

mknod: /dev/null: File exists

Populating /dev using udev: udevd (499): /proc/499/oom_adj is deprecated, please use /proc/499/oom_score_adj instead.

JFFS2 error: (500) jffs2_do_read_inode_internal: Argh. Special inode #1123 with mode 0x21b0 had more than one node

iget() failed for ino #1123

Question2：jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000024: 0x2b10 instead

mkfs.jffs2 -s 的参数问题对照FLASH的大小再重新生成镜像文件过即可

The answer this means that the data on your flash device is not a valid JFFS2 file system. There is no single solution for this problem, but we will try to provide you some ideas how to fix this.

The first question you should try to answer is "why the data on my flash device is incorrect so that JFFS2 rejects to deal with it?". There are may be a plenty of reasons, e.g.:

1. you flash driver is severely buggy so it reads trash instead of valid data;

2. you flashed some trash instead of a valid JFFS2 image;

3. you did not manage to flash JFFS2 image correctly so that you ended up with

garbage on your flash, although the original image was perfectly fine;

4. you forgot to erase your flash before flashing it, etc.

Anyways, JFFS2 wouldn't complain if it was able to find correct data. As it does complain, there is something wrong with the data it reads.

One common mistake is to use /dev/mtdX or /dev/mtdblockX devices to flash JFFS2 images on NAND flashes. E.g.

cp jffs2_fs.img /dev/mtd2

This is incorrect because when dealing with NAND flashes one has to skip bad eraseblocks and write only in NAND page size chunks. Please, use the nandwrite utility instead.

Also please, do not forget to erase your flash before flashing the image. You may use the flash_eraseall utility for this. And it makes sense to make sure the erase functionality actually works by reading the erased MTD device back and checking that only 0xFF bytes were read.

You may try to check if your flash driver works correctly and if you flashed the file system image correctly by means of reading the flash back after you have flashed your image, and compare the read image with the original one. Please, use the nandread utility to read from NAND flashes.

You can also do the following experiment to make sure JFFS2 works well. Erase your MTD device and mount it to JFFS2. You will end up with an empty file system. Copy some files to the JFFS2 file system and unmount it. Then mount it again and see if it mounts without problems. If it does, this is most probably not a JFFS2 bug.

Question3：Empty flash at 0xXXXXXXXX ends at 0xXXXXXXXX

This message is generated if a block of data is partially written. It is generally not a sign of any problem.

Question4：Name CRC failed on node at 0x00b620c8: Read 0x640c8ca3, calculated 0x795111fe

重启，则不会有如上CRC错误信息。

问题原因：

我在烧写jffs2 img之前，使用fis init -f 来擦除flash。fis init -f 命令执行完以后，flash空间就都是0xFF了！即使在mkfs.jffs2的时候使用'-p'参数指定最终输出img的大小，但是超出文件系统的部分也会被填充为0xFF!但这可不是jffs2的格式！

我用fis create分了5M多（0x590000）的分区，但是jffs2fs.img只有不到3M（0x250000），那么把它烧写到flash以后，分区中除了jffs2 img之外剩余的flash空间（大概2M）全是0xFF，这不是jffs2要求的格式，所以，会发出CRC错误的信息。假如有一种工具，他可以将flash format为jffs2的格式，那么就不会出现这个问题了。目前我还没有找到这种工具，但