AU: When generating delta, use scratch off end of filesystem

AU: When generating delta, use scratch off end of filesystem

This idea was originally coded by Darin Petkov, but was lost during a
separate bug fix a while ago. This CL restores the functionality.

The partition limit is set to 1GiB right now.

BUG=7444
TEST=tested generating/applying on host and checking results; unittest; tested specific case 110.9->128.4 that release engineers saw

Change-Id: I28a9a8d7025b83ec20b91e97dce5b783fc060b7c

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=927179d

[petkov, 2010-12-02 05:04:06]

Thanks for the quick turnaround. Some nits below. Also, did you test on the
110.9->128.4 delta?

LGTM otherwise.

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.cc
File delta_diff_generator.cc (right):

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.cc#newcode57
delta_diff_generator.cc:57: const size_t kRootFSPartitionSize = 1 * 1024 * 1024
* 1024;  // bytes
This is an obsolete dupe now? Remove.

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.cc#newcode60
delta_diff_generator.cc:60: const uint64_t kRootfsPartitionSize = 1024 * 1024 *
1024;  // bytes
Add a TODO to increase this to 2GiB when we stop caring about 1GiB devices any
more.

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.h
File delta_diff_generator.h (right):

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.h#newcode106
delta_diff_generator.h:106: // Creates a dummy REPLACE_BZ node in the given
vertex. This can be used
I assume there's no difference if it's REPLACE_BZ vs. REPLACE, the only point is
that it needs to be a write-only node?

Maybe change to "in the given |vertex|." and describe that the node writes
|num_blocks| blocks starting at |start_block|.

[adlr, 2010-12-02 19:21:41]

updated TEST= to show i did try that test case.

also did your suggestions and will soon push. thanks

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.cc
File delta_diff_generator.cc (right):

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.cc#newcode57
delta_diff_generator.cc:57: const size_t kRootFSPartitionSize = 1 * 1024 * 1024
* 1024;  // bytes
On 2010/12/02 05:04:06, petkov wrote:
> This is an obsolete dupe now? Remove.

Oops missed this. I decided to use this and not make the other

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.cc#newcode60
delta_diff_generator.cc:60: const uint64_t kRootfsPartitionSize = 1024 * 1024 *
1024;  // bytes
On 2010/12/02 05:04:06, petkov wrote:
> Add a TODO to increase this to 2GiB when we stop caring about 1GiB devices any
> more.

Done.

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.h
File delta_diff_generator.h (right):

http://codereview.chromium.org/5548002/diff/1/delta_diff_generator.h#newcode106
delta_diff_generator.h:106: // Creates a dummy REPLACE_BZ node in the given
vertex. This can be used
On 2010/12/02 05:04:06, petkov wrote:
> I assume there's no difference if it's REPLACE_BZ vs. REPLACE, the only point
is
> that it needs to be a write-only node?

Correct.

> 
> Maybe change to "in the given |vertex|." and describe that the node writes
> |num_blocks| blocks starting at |start_block|.

Done.