Re: [PATCH RESEND v5] fat: editions to support fat_fallocate

From: Namjae Jeon
Date: Thu Jun 20 2013 - 02:28:16 EST

2013/6/19, OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>:
> Namjae Jeon <linkinjeon@xxxxxxxxx> writes:
>>>If above is correct, right implement to change get_block().
>> Now when we try to write in the fallocated region ( with keep size) in
>> the fat_write_begin when it is called first time it checks that the
>> mismatch is present between the mmu_private and mmu_actual , and hence
>> zero out the region ; since buffer_new is not set for fallocated
>> region by fat_get_block , we explicitly zero out the lseeked region
>> using "fat_zero_falloc_area" and normal write occurs beyond that , and
>> i_size is updated accordingly , and as such there is no need to move
>> the code to fat_get_block .
> OK. So, like I said, you *changed* the behavior of get_block() via
> fallocate() change, right? (I think, now, you noticed fat_get_block()
> was changed.) Since you changed the behavior of get_block(), you had to
> hack write_begin(). (IMO, that patch is dirty hack to fix write_begin()
> path only)
> Likewise, you have to prove all callers of get_block() must work
> collectedly with that change.
> What happen on direct I/O, bmap ioctl, etc.? Well, anyway, please fix
> the root cause of change of behavior.
Good point!
Yes, I didn't consider direct I/O and bmap yet. Sure, I will fix it.
Thanks for review :)
> Thanks.
> --
> OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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