Re: [Yaffs] Complete partition data loss on powercut during …

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Author: Charles Manning
Date:  
To: Hunter Somerville
CC: yaffs
Subject: Re: [Yaffs] Complete partition data loss on powercut during write
On Tue, Feb 7, 2017 at 5:19 AM, Hunter Somerville <>
wrote:

> Hello,
>
> We are encountering an issue where we will usually lose an entire
> partition of data if the flash device loses power during a write operation.
> When we bring the system back up and remount, all files/directories appear
> as long strings of questionmarks with incorrect filenames and such, and we
> end up having to flash erase the partition to recover. This only happens on
> the device with fairly large pages (4MB Erase blocks, 32KB pages, 1KB OOB),
> and does not occur on the more typical device in the same system which uses
> 4KB pages.
>


What kind of flash are you using? What part number?


>
> Obviously these devices utilize different drivers and different hardware,
> so the cause might have nothing to do with YAFFS2. However, while we
> investigate other possible causes, we felt it might be worthwhile to ask if
> anyone else has seen this problem with YAFFS2 or if it could feasibly be
> related to the comparably very large page size.
>


People have used Yaffs with far larger page sizes than that.

Those questionmarks are probably 0xFF characters.

This sounds to me like some sort of driver side issue.

What OS are you using?

One way to debug this is to do binary dumps of the flash and look to see if
they make any sense. It is often better to work with a small partition for
test purposes just to reduce the amount of info you are working with (eg,
maybe 20 blocks).

-- Charles



>
> Thanks,
> Hunter Somerville
>
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