seeking help on JFFS2

[Jörn Engel]

On Tue, 5 November 2002 08:40:31 -0500, Junping Zhang wrote:
> 
>   I am new to MTD/JFFS2. Thanks to Christian Gagnaraud's patch, I got MTD
> working, but
> everytime I use JFFS2 on top of it, I get a kernel oops: "Oops: kernel
> access of 
> bad area, sig: 11"
> 
>   Here is my setup:
>     board:      MPC8260ADS
>     bootloader: ppcboot-1.1.6
>     kernel:     2.4.18
>     MTD/JFFS2:  mtd-snapshot-20021022.tar.bz2
>     RAM:        64M
>     flash:      8M
>     root disk:  ramdisk of 16M
>     host:       x86 with cross-compiler
> 
>   Here is the message of MTD from kernel startup:
>     Found: Intel 28F016S5
>     MPC8260ADS Bank 0: Found 4 x8 devices at 0x0 in 32-bit mode
>     Using word write method
>     MPC8260ADS flash bank 0: Using static image partition definition
>     Creating 4 MTD partitions on "MPC8260ADS Bank 0":
>     0x00000000-0x00700000 : "jffs2-root"
>     mtd: Giving out device 1 to jffs2-root
>     0x00700000-0x00740000 : "ppcboot"
>     mtd: Giving out device 2 to ppcboot
>     0x00740000-0x00780000 : "environment"
>     mtd: Giving out device 3 to environment
>     0x00780000-0x00800000 : "spare"
>     mtd: Giving out device 4 to spare
> 
>   Here is how I made oops happen:
>     eraseall /dev/mtd1
>     mount -t jffs2 /dev/mtdblock1 /mnt/flash
>     cp -R sbin /mnt/flash
> 
>   Here is the oops message through ksymoops:
>     >>NIP; c00e1938 <do_read_onechip+b8/4ec>   <=====
>     Trace; c0011480 <printk+15c/1b4>
>     Trace; c00df668 <cfi_intelext_read+b4/100>
>     Trace; c00e3be8 <part_read+68/a0>
>     Trace; c00a2ba0 <jffs2_mark_node_obsolete+468/88c>
>     Trace; c00a1fe0 <jffs2_do_reserve_space+264/55c>
>     Trace; c00a1b90 <jffs2_reserve_space+1b8/2d8>
>     Trace; c009df2c <jffs2_mkdir+54/454>
>     Trace; c0041d84 <vfs_mkdir+10c/130>
>     Trace; c0041e8c <sys_mkdir+e4/108>
>     Trace; c0003ddc <ret_from_syscall_1+0/b4>
>     Trace; 1002f4f0 Before first symbol
>     Trace; 100056c4 Before first symbol
>     Trace; 1002f2c8 Before first symbol
>     Trace; 1002ef18 Before first symbol
>     Trace; 0fecef70 Before first symbol
>     Trace; 00000000 Before first symbol
> 
>   Here are what I have tried:
>     (a) I tried plain JFFS on MTD, and it works. The steps I use:
> 
>         eraseall /dev/mtd1
>         mount -t jffs /dev/mtdblock1 /mnt/flash

Just to be on the safe side, can you make sure that /dev/mtd1 has minor
number 2? Common problem.

>         I can then copy/edit/delete from it, and diff shows that
>         the data is consistant.
> 
>         So I think MTD layer is fine and the configuration on MTD
>         part (.config) is fine.
> 
>     (b) I tried mkfs.jffs2 on both target and my x86 host (with
>         big-endian option)
> 
>         mkfs.jffs2 -dipc -e0x40000 -p0x700000 -b -o /opt/ipc.jffs2
                             ^^^^^^^   ^^^^^^^^
Does this really work? I remember that mkfs.jffs2 once didn't
understand hex and you had to pass it the decimal numbers. Can you
check that?

>         I then cp it on a mtd device with:
>         eraseall /dev/mtd1
>         cp /mnt/nfs/ipc.jffs2 /dev/mtd1
> 
>         the "cp" goes fine, but when I tried to mount & use the
>         JFFS2 system, within one or two commands, it will give me
>         the oops with the same reason "kernel access of bad area"
> 
>         But if I now boot into ppcboot(with JFFS2 capability compiled
>         in), ppcboot can recognize my JFFS2 files just fine, which
>         lead me to believe the linux JFFS2 subsystem is the problem.
> 
>     (c) I then tried disabling the compression for JFFS2 by forcing
>         return of JFFS2_COMPR_NONE from jffs2_compress() to see if 
>         zlib is a problem. It doesn't seem to have any effect.
> 
>   Any ideas? I have been reading the mailing list archive and could
> not find the answer to this.

jffs2 also mounts partitions that are completely erased. You can
eraseall /dev/mtd1 and then mount /dev/mtdblock1. That should work
fine.

Jörn

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