Problem mounting a UBIFS volume

[Adrian Hunter]

Bruce_Leonard at selinc.com wrote:
> Artem,
> 
> Sorry for the delay in replying, I was on holiday for a couple of weeks 
> and it's taken me a while to get my brain wrapped back around what I was 
> working on when I left :).
> 
> Artem Bityutskiy <dedekind at infradead.org> wrote on 07/04/2008 06:02:29 AM:
> 
>> On Wed, 2008-07-02 at 22:18 -0700, Bruce_Leonard at selinc.com wrote:
>>> UBIFS error (pid 842): check_lpt_crc:invalid crc in LPT node: crc 2bbb 
> 
>>> calc a5a5
>>> UBIFS error (pid 842): ubifs_read_nnode: error -22 reading nnode at 
> 8:6150
>>> mount: wrong fs type, bad option, bad superblock on ubi0:bob,
>>>        missing codepage or other error
>>>        In some cases useful info is found in syslog - try
>>>        dmesg | tail  or so
>> AFAIU, you still use a small flash and small image. So the only change
>> was your MTD change. Are you sure it is not the MTD change which is to
>> blame? Can you reproduce this error without your MTD change?
>>
> 
> Yes I can and here's what I've found.  I pulled the latest vanilla kernel 
> from Linus' tree (congratulations on getting UBIFS in BTW, very cool), 
> pulled the latest mkfs.ubifs, and did an entirely new clone of mtd-utils 
> (I wanted to get rid of my modifications).  So there are NONE of my MTD 
> changes in any of the code I'm currently using.  I also reset my driver to 
> only recognize 2GiB of NAND.  Before I left I was starting to get 
> suspicious of mkfs.ubifs, so I ran the following experiment this morning. 
> I used mkfs.ubifs to create two different images of the same filesystem 
> (one for up to 2GiB devices and one for up to 8GiB devices) as follows:
> 
> $ mkfs.ubifs -r x103/ -m 2048 -e 129024 -c 16384 -o x103.img
> $ mkfs.ubifs -r x103/ -m 2048 -e 129024 -c 65536 -o x103_large.img
> 
> If I understand things right (which usually isn't the case :-\), these 
> should be more or less the same, because the -c option is just specifying 
> a MAXIMUM volume size the image can be put onto.  An ls -l command gives 
> the following:
> 
> -rw-r--r--  1 root root  29159424 Jul 23 13:31 x103.img
> -rw-r--r--  1 root root  30449664 Jul 23 14:08 x103_large.img
> 
> So they match pretty close in size.  I can burn both images to my NAND 
> without errors by:
> 
> $ ubiupdatevol /dev/ubi0_0 x103*.img
> 
> When I try to mount the filesystem that comes from x103.img (the one for 
> the 'smaller' NAND flash) it mounts just fine, I can cd to it, create 
> directories/files, etc.  However, when I try to mount the filesystem from 
> x103_large.img, it fails with the following errors:
> 
> UBIFS error (pid 863): check_lpt_crc: invalid crc in LPT node: crc f486 
> calc e0b
> UBIFS error (pid 863): ubifs_read_nnode: error -22 reading nnode at 8:1356
> 
> mount: wrong fs type, bad option, bad superblock on ubi0:bob,
>        missing codepage or other error
>        In some cases useful info is found in syslog - try
>        dmesg | tail  or so
> 
> So, here's a couple of questions?  Does mkfs.ubifs and UBIFS calculate the 
> CRC identically or could there be a difference that's causing the problem? 
>  Does ubiupdatevol touch the CRC and that's what's causing the problem?  A 
> complicating factor, I'm running on an MPC8349E, which is big endian and I 
> know we've tripped across an endian issue in the past.  I've tried 
> eliminating endian issues by compiling and running all tools native on the 
> 8347, but could that be a factor?
> 
> I'm going to start by digging into mkfs.ubifs on the assumption that the 
> large -c parameter is causing it to some how miscalculate the CRC, but any 
> pointers of where else the problem could be are greatly appreciated.

Almost certainly mkfs.ubifs has screwed up the LPT.  That is because the
LPT is a tree that is sized according to the maximum size that the file system
can grow to i.e. the size given by the -c option

I will look at this.

Regards
Adrian