From: Chris Mason <chris.mason@oracle.com>
To: David Sterba <dsterba@suse.cz>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH][RFC] btrfs: fix potential overflow in leafsize accounting
Date: Fri, 17 Jun 2011 15:18:43 -0400 [thread overview]
Message-ID: <1308338282-sup-4067@shiny> (raw)
In-Reply-To: <1307986264-5707-1-git-send-email-dsterba@suse.cz>
Excerpts from David Sterba's message of 2011-06-13 13:31:04 -0400:
> smatch reported a dead code. It seems to allow wrong item size counting
> in leaves, as the first for loop does not adjust the maximum number for
> items that would fit in BTRFS_LEAF_DATA_SIZE, and the rest of the code
> works with the wrong value. The value of 'nr' is accompanied with
> accumulating total_data and total_size, which are compared to the leaf
> size and probably prevent this bug to do more harm, but the errorneously
> computed value of 'nr' is later used in moving existing items and lastly
> for setting up the item for new data.
>
> The bug has a potential to silently corrupt data when leaves are near to
> full, though I'm not aware of any related reports so far.
btrfs_insert_some_items is actually dead code. I've just deleted it
instead, but you're completely right that this is a bug.
-chris
prev parent reply other threads:[~2011-06-17 19:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-13 17:31 [PATCH][RFC] btrfs: fix potential overflow in leafsize accounting David Sterba
2011-06-17 19:18 ` Chris Mason [this message]
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