linux-ext4 - Re: [PATCH 1/5] ext4: Error out if verifying the block bitmap fails

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Message-ID: <20130828193609.GG27079@thunk.org>
Date:	Wed, 28 Aug 2013 15:36:09 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 1/5] ext4: Error out if verifying the block bitmap fails

On Fri, Jul 19, 2013 at 04:55:39PM -0700, Darrick J. Wong wrote:
> The block bitmap verification code assumes that calling ext4_error() either
> panics the system or makes the fs readonly.  However, this is not always true:
> when 'errors=continue' is specified, an error is printed but we don't return
> any indication of error to the caller, which is (probably) the block allocator,
> which pretends that the crud we read in off the disk is a usable bitmap.  Yuck.
> 
> A block bitmap that fails the check should at least return no bitmap to the
> caller.  The block allocator should be told to go look in a different group,
> but that's a separate issue.
> 
> The easiest way to reproduce this is to modify bg_block_bitmap (on a ^flex_bg
> fs) to point to a block outside the block group; or you can create a
> metadata_csum filesystem and zero out the block bitmaps.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>

Thanks, applied.

					- Ted
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