linux-kernel - Re: [PATCH 4.19 29/71] btrfs: tree-checker: Verify inode item

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Date:   Wed, 11 Nov 2020 14:38:21 +0100
From:   Pavel Machek <pavel@....cz>
To:     Qu Wenruo <wqu@...e.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Nikolay Borisov <nborisov@...e.com>,
        Johannes Thumshirn <jthumshirn@...e.de>,
        David Sterba <dsterba@...e.com>,
        Ben Hutchings <ben.hutchings@...ethink.co.uk>
Subject: Re: [PATCH 4.19 29/71] btrfs: tree-checker: Verify inode item

Hi!

> >> From: Qu Wenruo <wqu@...e.com>
> >>
> >> commit 496245cac57e26d8b738d85c7a29cf9a47610f3f upstream.
> >>
> >> There is a report in kernel bugzilla about mismatch file type in dir
> >> item and inode item.
> >>
> >> This inspires us to check inode mode in inode item.
> >>
> >> This patch will check the following members:
> > 
> >> +	/* Here we use super block generation + 1 to handle log tree */
> >> +	if (btrfs_inode_generation(leaf, iitem) > super_gen + 1) {
> >> +		inode_item_err(fs_info, leaf, slot,
> >> +			"invalid inode generation: has %llu expect (0, %llu]",
> >> +			       btrfs_inode_generation(leaf, iitem),
> >> +			       super_gen + 1);
> >> +		return -EUCLEAN;
> >> +	}
> > 
> > Printk suggests btrfs_inode_generation() may not be zero, but the
> > condition does not actually check that. Should that be added?
> 
> Sorry, btrfs_inode_generation() here is exactly what we're checking
> here, so what's wrong?

Quoted message says "(0, ...]", while message below says "[0, ...]". I
assume that means that btrfs_inode_generation() may not be zero in the
first case, but may be zero in the second case. But the code does not
test for zero here.

Best regards,
								Pavel

> >> +	/* Note for ROOT_TREE_DIR_ITEM, mkfs could set its transid 0 */
> >> +	if (btrfs_inode_transid(leaf, iitem) > super_gen + 1) {
> >> +		inode_item_err(fs_info, leaf, slot,
> >> +			"invalid inode generation: has %llu expect [0, %llu]",
> >> +			       btrfs_inode_transid(leaf, iitem), super_gen + 1);
> >> +		return -EUCLEAN;
> >> +	}

-- 
http://www.livejournal.com/~pavelmachek

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