AU: Use full rootfs partition for scratch.
This patch allows the delta generator to use blocks beyond rootfs up to
the full rootfs partition as scratch. This is really a stop gap solution.
The updater needs to be fixed to work with as little as one block of
scratch if necessary.
BUG=6531
TEST=unit tests, generated a delta payload and updated from 70.8 to 72.3
Change-Id: I52b7d04d5a5345c34c9c647f9878c836be9f489c
Review URL: http://codereview.chromium.org/3562001
diff --git a/delta_diff_generator.cc b/delta_diff_generator.cc
index 679f095..b38b495 100644
--- a/delta_diff_generator.cc
+++ b/delta_diff_generator.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
@@ -40,6 +40,7 @@
namespace {
const size_t kBlockSize = 4096;
+const size_t kRootFSPartitionSize = 1 * 1024 * 1024 * 1024; // 1 GiB
const uint64_t kVersionNumber = 1;
// Stores all Extents for a file into 'out'. Returns true on success.
@@ -209,32 +210,36 @@
return true;
}
-// Attempts to find block_count blocks to use as scratch space.
-// Returns true on success.
-// Right now we return exactly as many blocks as are required.
-// TODO(adlr): consider returning all scratch blocks,
-// even if there are extras, to make it easier for a scratch allocator
-// to find contiguous regions for specific scratch writes.
+// Attempts to find |block_count| blocks to use as scratch space. Returns true
+// on success. Right now we return exactly as many blocks as are required.
+//
+// TODO(adlr): Consider returning all scratch blocks, even if there are extras,
+// to make it easier for a scratch allocator to find contiguous regions for
+// specific scratch writes.
bool FindScratchSpace(const vector<Block>& blocks,
vector<Block>::size_type block_count,
vector<Extent>* out) {
- // Scan blocks for blocks that are neither read nor written.
- // If we don't find enough of those, return false.
- // TODO(adlr): return blocks that are written by
- // operations that don't have incoming edges (and thus, can be
- // deferred until all old blocks are read by other operations).
+ // Scan |blocks| for blocks that are neither read, nor written. If we don't
+ // find enough of those, look past the end of |blocks| till the end of the
+ // partition. If we don't find |block_count| scratch blocks, return false.
+ //
+ // TODO(adlr): Return blocks that are written by operations that don't have
+ // incoming edges (and thus, can be deferred until all old blocks are read by
+ // other operations).
vector<Extent> ret;
vector<Block>::size_type blocks_found = 0;
+ const size_t kPartitionBlocks = kRootFSPartitionSize / kBlockSize;
for (vector<Block>::size_type i = 0;
- i < blocks.size() && blocks_found < block_count; i++) {
- if (blocks[i].reader == Vertex::kInvalidIndex &&
- blocks[i].writer == Vertex::kInvalidIndex) {
+ i < kPartitionBlocks && blocks_found < block_count; i++) {
+ if (i >= blocks.size() ||
+ (blocks[i].reader == Vertex::kInvalidIndex &&
+ blocks[i].writer == Vertex::kInvalidIndex)) {
graph_utils::AppendBlockToExtents(&ret, i);
blocks_found++;
}
}
+ LOG(INFO) << "found " << blocks_found << " scratch blocks";
if (blocks_found == block_count) {
- LOG(INFO) << "returning " << blocks_found << " scratch blocks";
out->swap(ret);
return true;
}
@@ -874,7 +879,8 @@
const Extent& extent = op->dst_extents(j);
for (uint64_t block = extent.start_block();
block < (extent.start_block() + extent.num_blocks()); block++) {
- written_count[block]++;
+ if (block < blocks.size())
+ written_count[block]++;
}
}
if (op->has_data_offset()) {