linux-kernel - Re: [PATCH v3 2/6] fat: add fat

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Message-ID: <CAKYAXd80BFUMGYrON22Ui4xSMaxNJaHD1ss8bMVgdQqC4xG48A@mail.gmail.com>
Date:	Fri, 14 Feb 2014 13:53:26 +0900
From:	Namjae Jeon <linkinjeon@...il.com>
To:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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 v3 2/6] fat: add fat_fallocate operation

>> [...]
>>
>>> +		/* Release unwritten fallocated blocks on inode eviction. */
>>> +		if (MSDOS_I(inode)->mmu_private < MSDOS_I(inode)->i_disksize) {
>>> +			int err;
>>> +			fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
>>> +			/* Fallocate results in updating the i_start/iogstart
>>> +			 * for the zero byte file. So, make it return to
>>> +			 * original state during evict and commit it
>>> +			 * synchrnously to avoid any corruption on the next
>>> +			 * access to the cluster chain for the file.
>>> +			 */
>>> +			err = fat_sync_inode(inode);
>>
>> Ah, good catch. We have to update i_size. I was forgetting about this.
>> Well, sync inode unconditionally would not be good. Maybe, we better to
>> use __fat_write_inode() with inode_needs_sync() or such.
> Okay, I will change it.
Hi OGAWA

When I checked more, we should wait till inode is sync. Because in the
eviction it will leave the inode/buffers being marked dirty.
Not waiting for it get sync over here. It will leave cluster chain
corrupted when remounting.
It mean we cannot use __fat_write_inode with inode_needs_sync() conditionally.

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