linux-kernel - Re: [Ocfs2-devel] [PATCH v2 4/4] ocfs2: check/fix inode block for online file check

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Message-ID: <20151124221604.GX15575@wotan.suse.de>
Date:	Tue, 24 Nov 2015 14:16:04 -0800
From:	Mark Fasheh <mfasheh@...e.de>
To:	Junxiao Bi <junxiao.bi@...cle.com>
Cc:	Gang He <ghe@...e.com>, rgoldwyn@...e.de,
	linux-kernel@...r.kernel.org, ocfs2-devel@....oracle.com
Subject: Re: [Ocfs2-devel] [PATCH v2 4/4] ocfs2: check/fix inode block for
 online file check

Hi Junxiao,

On Tue, Nov 03, 2015 at 03:12:35PM +0800, Junxiao Bi wrote:
> Hi Gang,
> 
> This is not like a right patch.
> First, online file check only checks inode's block number, valid flag,
> fs generation value, and meta ecc. I never see a real corruption
> happened only on this field, if these fields are corrupted, that means
> something bad may happen on other place. So fix this field may not help
> and even cause corruption more hard.

I agree that these are rather uncommon, we might even consider removing the
VALID_FL fixup. I definitely don't think we're ready for anything more
complicated than this though either. We kind of have to start somewhere too.

> Second, the repair way is wrong. In
> ocfs2_filecheck_repair_inode_block(), if these fields in disk don't
> match the ones in memory, the ones in memory are used to update the disk
> fields. The question is how do you know these field in memory are
> right(they may be the real corrupted ones)?

Your second point (and the last part of your 1st point) makes a good
argument for why this shouldn't happen automatically. Some of these
corruptions might require a human to look at the log and decide what to do.
Especially as you point out, where we might not know where the source of the
corruption is. And if the human can't figure it out, then it's probably time
to unmount and fsck.

Thanks,
	--Mark

--
Mark Fasheh
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