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From: Boris Burkov <boris@bur.io>
To: Eric Biggers <ebiggers@kernel.org>
Cc: fstests@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH v2 2/3] generic/574: corrupt btrfs merkle tree data
Date: Thu, 8 Apr 2021 18:11:24 -0700	[thread overview]
Message-ID: <YG+pvMR57hJONugk@zen> (raw)
In-Reply-To: <YG+OzCaTUvp20w2/@sol.localdomain>

On Thu, Apr 08, 2021 at 04:16:28PM -0700, Eric Biggers wrote:
> On Thu, Apr 08, 2021 at 11:49:37AM -0700, Boris Burkov wrote:
> > On Thu, Apr 08, 2021 at 11:41:42AM -0700, Eric Biggers wrote:
> > > On Thu, Apr 08, 2021 at 11:30:12AM -0700, Boris Burkov wrote:
> > > > 
> > > > Note that there is a bit of a kludge here: since btrfs_corrupt_block
> > > > doesn't handle streaming corruption bytes from stdin (I could change
> > > > that, but it feels like overkill for this purpose), I just read the
> > > > first corruption byte and duplicate it for the desired length. That is
> > > > how the test is using the interface in practice, anyway.
> > > 
> > > If that's the problem, couldn't you just write the data to a temporary file?
> > 
> > Sorry, I was a bit too vague. It doesn't have a file or stdin interface,
> > as far as I know.
> > 
> > btrfs-corrupt-block has your typical "kitchen sink of flags" interface and
> > doesn't currently read input from streams/files. I extended that
> > interface in the simplest way to support arbitrary corruption, which
> > didn't fit with the stream based corruption this test does.
> > 
> > my options seem to be:
> > shoehorn the "byte, length" interface into this test or
> > shoehorn the "stream corruption input in" interface into
> > btrfs-corrupt-block.
> > 
> > I have no problem with either, the former was just less work because I
> > already wrote it that way. If the junk I did here is a deal-breaker, I
> > don't mind modifying btrfs-corrupt-block.
> > 
> 
> If it's a lot of trouble to handle arbitrary data, then I think you should
> change _fsv_scratch_corrupt_merkle_tree() to actually take a (byte, length) pair
> instead of data on stdin.  Otherwise, _fsv_scratch_corrupt_merkle_tree() would
> claim to do one thing but actually would do a different thing on one specific
> filesystem.
> 
> - Eric

It's no trouble. I think reading in corruption bytes will be a better
interface for btrfs-corrupt-block so I'll go ahead and do it.

  reply	other threads:[~2021-04-09  1:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08 18:30 [PATCH v2 0/3] tests for btrfs fsverity Boris Burkov
2021-04-08 18:30 ` [PATCH v2 1/3] btrfs: test btrfs specific fsverity corruption Boris Burkov
2021-04-08 18:30 ` [PATCH v2 2/3] generic/574: corrupt btrfs merkle tree data Boris Burkov
2021-04-08 18:41   ` Eric Biggers
2021-04-08 18:49     ` Boris Burkov
2021-04-08 23:16       ` Eric Biggers
2021-04-09  1:11         ` Boris Burkov [this message]
2021-04-08 18:30 ` [PATCH v2 3/3] btrfs: test verity orphans with dmlogwrites Boris Burkov
2021-04-08 18:36 ` [PATCH v2 0/3] tests for btrfs fsverity Eric Biggers
2021-04-08 18:42   ` Boris Burkov

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