v3 cow estimator
Use extent writer as abstraction layer for both estimation and ota
installation. Going over install operations will match the logic used
in delta_performer to accurattely size the cow. Extent_writer
abstraction takes care of chunking the data for us.
To account for FEC data and hash tree writes, we want to add a little
bit of overhead as AddRawBlocks calls are per verity hash tree level. In
the case of small partitions, we want to set the overhead to a hard
number rather than a percentile
To ensure that our estimator is backwards compatible for downgrade
OTA's, we should add labels after each operation is processed (although
this isn't needed for sizing a v3 cow).
Bug: 322279333
Test: OTA on cuttlefish
Change-Id: I46f9da30641778095ee8543d7627320e309b9359
diff --git a/payload_generator/cow_size_estimator.cc b/payload_generator/cow_size_estimator.cc
index bb12113..eb84d45 100644
--- a/payload_generator/cow_size_estimator.cc
+++ b/payload_generator/cow_size_estimator.cc
@@ -17,7 +17,6 @@
#include "update_engine/payload_generator/cow_size_estimator.h"
#include <algorithm>
-#include <functional>
#include <string>
#include <utility>
#include <vector>
@@ -26,6 +25,9 @@
#include <libsnapshot/cow_writer.h>
#include <libsnapshot/cow_format.h>
+#include "update_engine/payload_consumer/block_extent_writer.h"
+#include "update_engine/payload_consumer/snapshot_extent_writer.h"
+#include "update_engine/payload_consumer/xor_extent_writer.h"
#include "update_engine/common/utils.h"
#include "update_engine/payload_consumer/vabc_partition_writer.h"
#include "update_engine/payload_generator/extent_ranges.h"
@@ -35,6 +37,17 @@
namespace chromeos_update_engine {
using android::snapshot::CreateCowEstimator;
using android::snapshot::ICowWriter;
+// Compute XOR map, a map from dst extent to corresponding merge operation
+static ExtentMap<const CowMergeOperation*, ExtentLess> ComputeXorMap(
+ const google::protobuf::RepeatedPtrField<CowMergeOperation>& merge_ops) {
+ ExtentMap<const CowMergeOperation*, ExtentLess> xor_map;
+ for (const auto& merge_op : merge_ops) {
+ if (merge_op.type() == CowMergeOperation::COW_XOR) {
+ xor_map.AddExtent(merge_op.dst_extent(), &merge_op);
+ }
+ }
+ return xor_map;
+}
bool CowDryRun(
FileDescriptorPtr source_fd,
@@ -50,71 +63,96 @@
CHECK(target_fd->IsOpen());
VABCPartitionWriter::WriteMergeSequence(merge_operations, cow_writer);
ExtentRanges visited;
- for (const auto& op : merge_operations) {
- if (op.type() == CowMergeOperation::COW_COPY) {
- visited.AddExtent(op.dst_extent());
- cow_writer->AddCopy(op.dst_extent().start_block(),
- op.src_extent().start_block(),
- op.dst_extent().num_blocks());
- } else if (op.type() == CowMergeOperation::COW_XOR && xor_enabled) {
- CHECK_NE(source_fd, nullptr) << "Source fd is required to enable XOR ops";
- CHECK(source_fd->IsOpen());
- visited.AddExtent(op.dst_extent());
- // dst block count is used, because
- // src block count is probably(if src_offset > 0) 1 block
- // larger than dst extent. Using it might lead to intreseting out of bound
- // disk reads.
- std::vector<unsigned char> old_data(op.dst_extent().num_blocks() *
- block_size);
- ssize_t bytes_read = 0;
- if (!utils::PReadAll(
- source_fd,
- old_data.data(),
- old_data.size(),
- op.src_extent().start_block() * block_size + op.src_offset(),
- &bytes_read)) {
- PLOG(ERROR) << "Failed to read source data at " << op.src_extent();
- return false;
- }
- std::vector<unsigned char> new_data(op.dst_extent().num_blocks() *
- block_size);
- if (!utils::PReadAll(target_fd,
- new_data.data(),
- new_data.size(),
- op.dst_extent().start_block() * block_size,
- &bytes_read)) {
- PLOG(ERROR) << "Failed to read target data at " << op.dst_extent();
- return false;
- }
- CHECK_GT(old_data.size(), 0UL);
- CHECK_GT(new_data.size(), 0UL);
- std::transform(new_data.begin(),
- new_data.end(),
- old_data.begin(),
- new_data.begin(),
- std::bit_xor<unsigned char>{});
- CHECK(cow_writer->AddXorBlocks(op.dst_extent().start_block(),
- new_data.data(),
- new_data.size(),
- op.src_extent().start_block(),
- op.src_offset()));
+ SnapshotExtentWriter extent_writer(cow_writer);
+ ExtentMap<const CowMergeOperation*, ExtentLess> xor_map =
+ ComputeXorMap(merge_operations);
+ ExtentRanges copy_blocks;
+ for (const auto& cow_op : merge_operations) {
+ if (cow_op.type() != CowMergeOperation::COW_COPY) {
+ continue;
}
- // The value of label doesn't really matter, we just want to write some
- // labels to simulate bahvior of update_engine. As update_engine writes
- // labels every once a while when installing OTA, it's important that we do
- // the same to get accurate size estimation.
- cow_writer->AddLabel(0);
+ copy_blocks.AddExtent(cow_op.dst_extent());
}
for (const auto& op : operations) {
- cow_writer->AddLabel(0);
- if (op.type() == InstallOperation::ZERO) {
- for (const auto& ext : op.dst_extents()) {
- visited.AddExtent(ext);
- cow_writer->AddZeroBlocks(ext.start_block(), ext.num_blocks());
+ switch (op.type()) {
+ case InstallOperation::SOURCE_BSDIFF:
+ case InstallOperation::BROTLI_BSDIFF:
+ case InstallOperation::PUFFDIFF:
+ case InstallOperation::ZUCCHINI:
+ case InstallOperation::LZ4DIFF_PUFFDIFF:
+ case InstallOperation::LZ4DIFF_BSDIFF: {
+ if (xor_enabled) {
+ std::unique_ptr<XORExtentWriter> writer =
+ std::make_unique<XORExtentWriter>(
+ op, source_fd, cow_writer, xor_map, partition_size);
+ TEST_AND_RETURN_FALSE(writer->Init(op.dst_extents(), block_size));
+ for (const auto& ext : op.dst_extents()) {
+ visited.AddExtent(ext);
+ ssize_t bytes_read = 0;
+ std::vector<unsigned char> new_data(ext.num_blocks() * block_size);
+ if (!utils::PReadAll(target_fd,
+ new_data.data(),
+ new_data.size(),
+ ext.start_block() * block_size,
+ &bytes_read)) {
+ PLOG(ERROR) << "Failed to read target data at " << ext;
+ return false;
+ }
+ writer->Write(new_data.data(), ext.num_blocks() * block_size);
+ }
+ cow_writer->AddLabel(0);
+ break;
+ }
+ [[fallthrough]];
}
+ case InstallOperation::REPLACE:
+ case InstallOperation::REPLACE_BZ:
+ case InstallOperation::REPLACE_XZ: {
+ TEST_AND_RETURN_FALSE(extent_writer.Init(op.dst_extents(), block_size));
+ for (const auto& ext : op.dst_extents()) {
+ visited.AddExtent(ext);
+ std::vector<unsigned char> data(ext.num_blocks() * block_size);
+ ssize_t bytes_read = 0;
+ if (!utils::PReadAll(target_fd,
+ data.data(),
+ data.size(),
+ ext.start_block() * block_size,
+ &bytes_read)) {
+ PLOG(ERROR) << "Failed to read new block data at " << ext;
+ return false;
+ }
+ extent_writer.Write(data.data(), data.size());
+ }
+ cow_writer->AddLabel(0);
+ break;
+ }
+ case InstallOperation::ZERO:
+ case InstallOperation::DISCARD: {
+ for (const auto& ext : op.dst_extents()) {
+ visited.AddExtent(ext);
+ cow_writer->AddZeroBlocks(ext.start_block(), ext.num_blocks());
+ }
+ cow_writer->AddLabel(0);
+ break;
+ }
+ case InstallOperation::SOURCE_COPY: {
+ for (const auto& ext : op.dst_extents()) {
+ visited.AddExtent(ext);
+ }
+ if (!VABCPartitionWriter::ProcessSourceCopyOperation(
+ op, block_size, copy_blocks, source_fd, cow_writer, true)) {
+ LOG(ERROR) << "Failed to process source copy operation: " << op.type()
+ << "\nsource extents: " << op.src_extents()
+ << "\ndestination extents: " << op.dst_extents();
+ return false;
+ }
+ break;
+ }
+ default:
+ LOG(ERROR) << "unknown op: " << op.type();
}
}
- cow_writer->AddLabel(0);
+
const size_t last_block = partition_size / block_size;
const auto unvisited_extents =
FilterExtentRanges({ExtentForRange(0, last_block)}, visited);
@@ -129,11 +167,23 @@
PLOG(ERROR) << "Failed to read new block data at " << ext;
return false;
}
- cow_writer->AddRawBlocks(ext.start_block(), data.data(), data.size());
+ auto to_write = data.size();
+ // FEC data written on device is chunked to 1mb. We want to mirror that here
+ while (to_write) {
+ auto curr_write = std::min(block_size, to_write);
+ cow_writer->AddRawBlocks(
+ ext.start_block() + ((data.size() - to_write) / block_size),
+ data.data() + (data.size() - to_write),
+ curr_write);
+ to_write -= curr_write;
+ }
+ CHECK_EQ(to_write, 0ULL);
cow_writer->AddLabel(0);
}
- return cow_writer->Finalize();
+ TEST_AND_RETURN_FALSE(cow_writer->Finalize());
+
+ return true;
}
android::snapshot::CowSizeInfo EstimateCowSizeInfo(
diff --git a/payload_generator/delta_diff_generator.cc b/payload_generator/delta_diff_generator.cc
index fb967fd..ed9bf4e 100644
--- a/payload_generator/delta_diff_generator.cc
+++ b/payload_generator/delta_diff_generator.cc
@@ -128,11 +128,8 @@
*operations.Add() = aop.op;
}
- FileDescriptorPtr source_fd = nullptr;
- if (config_.enable_vabc_xor) {
- source_fd = std::make_shared<EintrSafeFileDescriptor>();
- source_fd->Open(old_part_.path.c_str(), O_RDONLY);
- }
+ FileDescriptorPtr source_fd = std::make_shared<EintrSafeFileDescriptor>();
+ source_fd->Open(old_part_.path.c_str(), O_RDONLY);
*cow_info_ = EstimateCowSizeInfo(
std::move(source_fd),
@@ -146,6 +143,10 @@
config_.target.dynamic_partition_metadata->cow_version(),
config_.target.dynamic_partition_metadata->compression_factor());
+ // add a 1% overhead to our estimation
+ cow_info_->cow_size += cow_info_->cow_size * 1.01;
+ cow_info_->op_count_max +=
+ std::max(int(cow_info_->op_count_max * 1.01), 25);
// ops buffer size == 0 for v2 version of cow format
LOG(INFO) << "Estimated COW size for partition: " << new_part_.name << " "
<< cow_info_->cow_size
