From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Namjae Jeon <linkinjeon@gmail.com>
Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Namjae Jeon <namjae.jeon@samsung.com>,
        Amit Sahrawat <a.sahrawat@samsung.com>
Subject: Re: [PATCH RESEND v5] fat: editions to support fat_fallocate
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Date: Wed, 19 Jun 2013 02:33:01 +0900
In-Reply-To: <CAKYAXd8kyN1w5GJ8zCoKL+XS67125dUf0ivqCQWKjGCSxnXYpg@mail.gmail.com>
	(Namjae Jeon's message of "Tue, 18 Jun 2013 14:47:10 +0900")
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Namjae Jeon <linkinjeon@gmail.com> 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.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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