linux-kernel - Re: [PATCH] vfs: Fix vmtruncate() regression

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Message-ID: <87r5pucin4.fsf@devron.myhome.or.jp>
Date:	Wed, 13 Jan 2010 21:07:59 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Nick Piggin <npiggin@...e.de>
Cc:	Al Viro <viro@...iv.linux.org.uk>, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH] vfs: Fix vmtruncate() regression

Nick Piggin <npiggin@...e.de> writes:

>> If __block_prepare_write() was failed in block_write_begin(), the
>> allocated blocks can be outside of ->i_size.
>> 
>> But new truncate_pagecache() in vmtuncate() does nothing if new < old.
>> It means the above usage is not working anymore.
>> 
>> So, this patch fixes it by removing "new < old" check. It would need
>> more cleanup/change. But, now -rc and truncate working is in progress,
>> so, this tried to fix it minimum change.
>> 
>> Cc: stable@...nel.org
>> Signed-off-by: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
>
> Hmm, truncate_pagecache() is for truncating the mm/vm part of the
> pagecache. vmtruncate should still call inode->i_op->truncate() to
> trim blocks if required.
>
> However I'd say we do still need to ensure do_invalidatepage is
> called for the page, for private metadata. So yes I think your patch
> looks good.

Thanks for reviewing. Yes, and it also needs to be called to ensure that
have the same state on-disk and page/bh state. [BTW, this became the
cause of fatfs corruption.]

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