[U-Boot] [BUG] cb8af8af5ba0 "fs: fat: support write with non-zero offset" fatwrite followed by fatload and then cmp fails

[Rizvi, Mohammad Faiz Abbas]

Tom,

On 3/12/2019 2:11 PM, Faiz Abbas wrote:
> Hi Akashi,
> 
> On 11/09/18 12:29 PM, Akashi, Takahiro wrote:
>> From: AKASHI Takahiro <takahiro.akashi at linaro.org>
>>
>> The current write implementation is quite simple: remove existing clusters
>> and then allocating new ones and filling them with data. This, inevitably,
>> enforces always writing from the beginning of a file.
>>
>> As the first step to lift this restriction, fat_file_write() and
>> set_contents() are modified to accept an additional parameter, file offset
>> and further re-factored so that, in the next patch, all the necessary code
>> will be put into set_contents().
>>
>> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>> ---
> 
> My fatwrite, fatload and compare tests are failing in MMC with this
> commit. This is what I see:
> 
> => fatwrite mmc 0 ${loadaddr} test 0x2000000
> 33554432 bytes written
> => fatload mmc 0 84000000 test
> 33554432 bytes read in 2149 ms (14.9 MiB/s)
> => cmp.b 82000000 84000000 0x2000000
> byte at 0x820c5000 (0x85) != byte at 0x840c5000 (0x9d)
> Total of 806912 byte(s) were the same
> =>
> 
> Reverting this commit fixes this issue for me.
> 
> Thanks,
> Faiz
> 

We have about 100 boards failing to boot from SD card because of fat
filesystem corruption in our test farm (likely) because of this patch. I
am afraid we will have to revert it until something stable can be
figured out. Will send out reverts tomorrow. Hopefully they can be
reviewed and merged quickly.

Thanks,
Faiz