[U-Boot] [PATCH V4 1/2] ext4fs ls load support

Rob Herring robherring2 at gmail.com
Tue Mar 27 15:46:36 CEST 2012

On 03/27/2012 08:13 AM, manjunatha wrote:
> Dear Rob Herring/ Wolfgang,
> As discussed in earlier mail chain, our current ext4 implementation is
> capable enough to list(ls) and read(load) ext2 partitons as well.
> Also the current ext4 implementation is optimized to 7-8 times greater
> read throughput than ext2load.

Cool. IIRC, there was just recently some discussion on the list about
ext2 performance problems.

> I propose that we can remove the existing ext2 code and let it be
> replaced with ext4.

That's exactly what I proposed. Although, I think your patch should be
done as modifications to cmd_ext2.c rather than deleting it and adding a
new cmd_ext4.c.

> All users using ext2ls and ext2load command can replace them with ext4ls
> and ext4load respectively.

I think you need to keep the command names to not break existing users'
scripts. So either we just stick with ext2ls/ext2load or define
additional ext4* commands which call the same functions as the ext2
version. I don't really care, but would lean toward the former.


> The ext4 code is based on ext2 implementation and we have added the
> names of respective owners(ext2 code authors) in the file headers.
> Please suggest what could be the best approach.
> Thanks & Regards,
> Manjunatha C achar
> --------------------------------------------------
> From: "Rob Herring" <robherring2 at gmail.com>
> Sent: Monday, March 26, 2012 6:40 PM
> To: <uma.shankar at samsung.com>
> Cc: <u-boot at lists.denx.de>; "MANJUNATHAC ACHAR"
> <a.manjunatha at samsung.com>; <kim.phillips at freescale.com>; "IQBAL
> SHAREEF" <iqbal.ams at samsung.com>; "HAKGOO LEE"
> <goodguy.lee at samsung.com>; <wd at denx.de>
> Subject: Re: [U-Boot] [PATCH V4 1/2] ext4fs ls load support
>> On 03/26/2012 02:24 AM, UMA SHANKAR wrote:
>>> Dear Rob Herring, Thanks for evaluating and testing our code.
>>> Currently, Our ext4 implementation is capable of listing and reading
>>> (ls and load) ext2 partitions as well. But, we wanted the ext4 code
>>> to be separate from ext2 implementation.
>> Why?
>>> Your comment: --- Using ext2 commands on an ext4 partition will hang
>>> now.
>>> ext2load command will only read ext2 partitions, and will definitely
>>> not work on ext4 (even without our implementation).
>> I'm not saying it should work, but it shouldn't hang. IIRC without your
>> patch, it would return with an error. So you have changed something in
>> the core ext2 code that makes it hang. But it's not something I think
>> you need to worry about as the ext4 version of code should just replace
>> the ext2 version and the issue will go away.
>> Rob
>>>   So, I propose, we can let both these implementations be there in
>>> uboot under different CONFIG Options (as is the case currently).  
>>> Thanks & Regards, Uma Shankar

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