linux-kernel - Re: [PATCH RESEND v5] fat: editions to support fat

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Date:	Wed, 19 Jun 2013 02:33:01 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Namjae Jeon <linkinjeon@...il.com>
Cc:	akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Namjae Jeon <namjae.jeon@...sung.com>,
	Amit Sahrawat <a.sahrawat@...sung.com>
Subject: Re: [PATCH RESEND v5] fat: editions to support fat_fallocate

Namjae Jeon <linkinjeon@...il.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@...l.parknet.co.jp>
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