[RFC/PATCH 1/5] mtd: ubi: Read disturb infrastructure

[Richard Weinberger]

Am 28.09.2014 10:48, schrieb Tanya Brokhman:
>>> @@ -424,6 +440,8 @@ struct ubi_fm_sb {
>>>       __be32 used_blocks;
>>>       __be32 block_loc[UBI_FM_MAX_BLOCKS];
>>>       __be32 block_ec[UBI_FM_MAX_BLOCKS];
>>> +    __be32 block_rc[UBI_FM_MAX_BLOCKS];
>>> +    __be64 block_let[UBI_FM_MAX_BLOCKS];
>>
>> Doesn't this break the fastmap on-disk layout?
> 
> What do you mean "break"? I verified fastmap feature is working. the whole read-disturb depends on it so I tested this thoroughly.

Did you write a fastmap with your changes applied and then an attach using a fastmap implementation *without*
you changes?
I bet it will not work because the disk layout is now different.
Linux is not the only user of fastmap. We need to be very careful here.

Thanks,
//richard