android_system_core/fs_mgr/liblp/builder.cpp
David Anderson 7a6c511a6d liblp: Add an abstraction layer for opening partitions.
This change introduces an IPartitionOpener abstraction. Methods that
interact with live metadata, such as ReadMetadata, UpdatePartitionTable,
and FlashPartitionTable, now require an IPartitionOpener object. Its
purpose is dependency injection: it will make these methods much easier
to test when the super partition spans multiple block devices.

All non-test consumers should be using PartitionOpener, and as such,
some helper methods have been added that automatically create one.

Bug: 116802789
Test: liblp_test gtest
      device with super partition boots
Change-Id: I76725a5830ef643c5007c152c00ccaad8085151f
2018-10-24 14:18:38 -07:00

636 lines
23 KiB
C++

/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "liblp/builder.h"
#include <string.h>
#include <algorithm>
#include <android-base/unique_fd.h>
#include "liblp/liblp.h"
#include "reader.h"
#include "utility.h"
namespace android {
namespace fs_mgr {
void LinearExtent::AddTo(LpMetadata* out) const {
out->extents.push_back(LpMetadataExtent{num_sectors_, LP_TARGET_TYPE_LINEAR, physical_sector_});
}
void ZeroExtent::AddTo(LpMetadata* out) const {
out->extents.push_back(LpMetadataExtent{num_sectors_, LP_TARGET_TYPE_ZERO, 0});
}
Partition::Partition(const std::string& name, const std::string& group_name, uint32_t attributes)
: name_(name), group_name_(group_name), attributes_(attributes), size_(0) {}
void Partition::AddExtent(std::unique_ptr<Extent>&& extent) {
size_ += extent->num_sectors() * LP_SECTOR_SIZE;
if (LinearExtent* new_extent = extent->AsLinearExtent()) {
if (!extents_.empty() && extents_.back()->AsLinearExtent() &&
extents_.back()->AsLinearExtent()->end_sector() == new_extent->physical_sector()) {
// If the previous extent can be merged into this new one, do so
// to avoid creating unnecessary extents.
LinearExtent* prev_extent = extents_.back()->AsLinearExtent();
extent = std::make_unique<LinearExtent>(
prev_extent->num_sectors() + new_extent->num_sectors(),
prev_extent->physical_sector());
extents_.pop_back();
}
}
extents_.push_back(std::move(extent));
}
void Partition::RemoveExtents() {
size_ = 0;
extents_.clear();
}
void Partition::ShrinkTo(uint64_t aligned_size) {
if (aligned_size == 0) {
RemoveExtents();
return;
}
// Remove or shrink extents of any kind until the total partition size is
// equal to the requested size.
uint64_t sectors_to_remove = (size_ - aligned_size) / LP_SECTOR_SIZE;
while (sectors_to_remove) {
Extent* extent = extents_.back().get();
if (extent->num_sectors() > sectors_to_remove) {
size_ -= sectors_to_remove * LP_SECTOR_SIZE;
extent->set_num_sectors(extent->num_sectors() - sectors_to_remove);
break;
}
size_ -= (extent->num_sectors() * LP_SECTOR_SIZE);
sectors_to_remove -= extent->num_sectors();
extents_.pop_back();
}
DCHECK(size_ == aligned_size);
}
uint64_t Partition::BytesOnDisk() const {
uint64_t sectors = 0;
for (const auto& extent : extents_) {
if (!extent->AsLinearExtent()) {
continue;
}
sectors += extent->num_sectors();
}
return sectors * LP_SECTOR_SIZE;
}
std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const IPartitionOpener& opener,
const std::string& super_partition,
uint32_t slot_number) {
std::unique_ptr<LpMetadata> metadata = ReadMetadata(opener, super_partition, slot_number);
if (!metadata) {
return nullptr;
}
std::unique_ptr<MetadataBuilder> builder = New(*metadata.get());
if (!builder) {
return nullptr;
}
BlockDeviceInfo device_info;
if (opener.GetInfo(super_partition, &device_info)) {
builder->UpdateBlockDeviceInfo(device_info);
}
return builder;
}
std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const std::string& super_partition,
uint32_t slot_number) {
return New(PartitionOpener(), super_partition, slot_number);
}
std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const BlockDeviceInfo& device_info,
uint32_t metadata_max_size,
uint32_t metadata_slot_count) {
std::unique_ptr<MetadataBuilder> builder(new MetadataBuilder());
if (!builder->Init(device_info, metadata_max_size, metadata_slot_count)) {
return nullptr;
}
return builder;
}
std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const LpMetadata& metadata) {
std::unique_ptr<MetadataBuilder> builder(new MetadataBuilder());
if (!builder->Init(metadata)) {
return nullptr;
}
return builder;
}
MetadataBuilder::MetadataBuilder() {
memset(&geometry_, 0, sizeof(geometry_));
geometry_.magic = LP_METADATA_GEOMETRY_MAGIC;
geometry_.struct_size = sizeof(geometry_);
memset(&header_, 0, sizeof(header_));
header_.magic = LP_METADATA_HEADER_MAGIC;
header_.major_version = LP_METADATA_MAJOR_VERSION;
header_.minor_version = LP_METADATA_MINOR_VERSION;
header_.header_size = sizeof(header_);
header_.partitions.entry_size = sizeof(LpMetadataPartition);
header_.extents.entry_size = sizeof(LpMetadataExtent);
header_.groups.entry_size = sizeof(LpMetadataPartitionGroup);
header_.block_devices.entry_size = sizeof(LpMetadataBlockDevice);
}
bool MetadataBuilder::Init(const LpMetadata& metadata) {
geometry_ = metadata.geometry;
for (const auto& group : metadata.groups) {
std::string group_name = GetPartitionGroupName(group);
if (!AddGroup(group_name, group.maximum_size)) {
return false;
}
}
for (const auto& block_device : metadata.block_devices) {
block_devices_.push_back(block_device);
}
for (const auto& partition : metadata.partitions) {
std::string group_name = GetPartitionGroupName(metadata.groups[partition.group_index]);
Partition* builder =
AddPartition(GetPartitionName(partition), group_name, partition.attributes);
if (!builder) {
return false;
}
for (size_t i = 0; i < partition.num_extents; i++) {
const LpMetadataExtent& extent = metadata.extents[partition.first_extent_index + i];
if (extent.target_type == LP_TARGET_TYPE_LINEAR) {
auto copy = std::make_unique<LinearExtent>(extent.num_sectors, extent.target_data);
builder->AddExtent(std::move(copy));
} else if (extent.target_type == LP_TARGET_TYPE_ZERO) {
auto copy = std::make_unique<ZeroExtent>(extent.num_sectors);
builder->AddExtent(std::move(copy));
}
}
}
return true;
}
bool MetadataBuilder::Init(const BlockDeviceInfo& device_info, uint32_t metadata_max_size,
uint32_t metadata_slot_count) {
if (metadata_max_size < sizeof(LpMetadataHeader)) {
LERROR << "Invalid metadata maximum size.";
return false;
}
if (metadata_slot_count == 0) {
LERROR << "Invalid metadata slot count.";
return false;
}
// Align the metadata size up to the nearest sector.
metadata_max_size = AlignTo(metadata_max_size, LP_SECTOR_SIZE);
// Check that device properties are sane.
if (device_info.size % LP_SECTOR_SIZE != 0) {
LERROR << "Block device size must be a multiple of 512.";
return false;
}
if (device_info.logical_block_size % LP_SECTOR_SIZE != 0) {
LERROR << "Logical block size must be a multiple of 512.";
return false;
}
if (device_info.alignment_offset % LP_SECTOR_SIZE != 0) {
LERROR << "Alignment offset is not sector-aligned.";
return false;
}
if (device_info.alignment % LP_SECTOR_SIZE != 0) {
LERROR << "Partition alignment is not sector-aligned.";
return false;
}
if (device_info.alignment_offset > device_info.alignment) {
LERROR << "Partition alignment offset is greater than its alignment.";
return false;
}
// We reserve a geometry block (4KB) plus space for each copy of the
// maximum size of a metadata blob. Then, we double that space since
// we store a backup copy of everything.
uint64_t total_reserved = GetTotalMetadataSize(metadata_max_size, metadata_slot_count);
if (device_info.size < total_reserved) {
LERROR << "Attempting to create metadata on a block device that is too small.";
return false;
}
// Compute the first free sector, factoring in alignment.
uint64_t free_area_start = total_reserved;
if (device_info.alignment || device_info.alignment_offset) {
free_area_start =
AlignTo(free_area_start, device_info.alignment, device_info.alignment_offset);
} else {
free_area_start = AlignTo(free_area_start, device_info.logical_block_size);
}
uint64_t first_sector = free_area_start / LP_SECTOR_SIZE;
// There must be one logical block of free space remaining (enough for one partition).
uint64_t minimum_disk_size = (first_sector * LP_SECTOR_SIZE) + device_info.logical_block_size;
if (device_info.size < minimum_disk_size) {
LERROR << "Device must be at least " << minimum_disk_size << " bytes, only has "
<< device_info.size;
return false;
}
block_devices_.push_back(LpMetadataBlockDevice{
first_sector,
device_info.alignment,
device_info.alignment_offset,
device_info.size,
"super",
});
geometry_.metadata_max_size = metadata_max_size;
geometry_.metadata_slot_count = metadata_slot_count;
geometry_.logical_block_size = device_info.logical_block_size;
if (!AddGroup("default", 0)) {
return false;
}
return true;
}
bool MetadataBuilder::AddGroup(const std::string& group_name, uint64_t maximum_size) {
if (FindGroup(group_name)) {
LERROR << "Group already exists: " << group_name;
return false;
}
groups_.push_back(std::make_unique<PartitionGroup>(group_name, maximum_size));
return true;
}
Partition* MetadataBuilder::AddPartition(const std::string& name, uint32_t attributes) {
return AddPartition(name, "default", attributes);
}
Partition* MetadataBuilder::AddPartition(const std::string& name, const std::string& group_name,
uint32_t attributes) {
if (name.empty()) {
LERROR << "Partition must have a non-empty name.";
return nullptr;
}
if (FindPartition(name)) {
LERROR << "Attempting to create duplication partition with name: " << name;
return nullptr;
}
if (!FindGroup(group_name)) {
LERROR << "Could not find partition group: " << group_name;
return nullptr;
}
partitions_.push_back(std::make_unique<Partition>(name, group_name, attributes));
return partitions_.back().get();
}
Partition* MetadataBuilder::FindPartition(const std::string& name) {
for (const auto& partition : partitions_) {
if (partition->name() == name) {
return partition.get();
}
}
return nullptr;
}
PartitionGroup* MetadataBuilder::FindGroup(const std::string& group_name) {
for (const auto& group : groups_) {
if (group->name() == group_name) {
return group.get();
}
}
return nullptr;
}
uint64_t MetadataBuilder::TotalSizeOfGroup(PartitionGroup* group) const {
uint64_t total = 0;
for (const auto& partition : partitions_) {
if (partition->group_name() != group->name()) {
continue;
}
total += partition->BytesOnDisk();
}
return total;
}
void MetadataBuilder::RemovePartition(const std::string& name) {
for (auto iter = partitions_.begin(); iter != partitions_.end(); iter++) {
if ((*iter)->name() == name) {
partitions_.erase(iter);
return;
}
}
}
void MetadataBuilder::ExtentsToFreeList(const std::vector<Interval>& extents,
std::vector<Interval>* free_regions) const {
// Convert the extent list into a list of gaps between the extents; i.e.,
// the list of ranges that are free on the disk.
for (size_t i = 1; i < extents.size(); i++) {
const Interval& previous = extents[i - 1];
const Interval& current = extents[i];
uint64_t aligned = AlignSector(previous.end);
if (aligned >= current.start) {
// There is no gap between these two extents, try the next one.
// Note that we check with >= instead of >, since alignment may
// bump the ending sector past the beginning of the next extent.
continue;
}
// The new interval represents the free space starting at the end of
// the previous interval, and ending at the start of the next interval.
free_regions->emplace_back(aligned, current.start);
}
}
auto MetadataBuilder::GetFreeRegions() const -> std::vector<Interval> {
std::vector<Interval> free_regions;
// Collect all extents in the partition table, then sort them by starting
// sector.
std::vector<Interval> extents;
for (const auto& partition : partitions_) {
for (const auto& extent : partition->extents()) {
LinearExtent* linear = extent->AsLinearExtent();
if (!linear) {
continue;
}
extents.emplace_back(linear->physical_sector(),
linear->physical_sector() + extent->num_sectors());
}
}
// Add 0-length intervals for the first and last sectors. This will cause
// ExtentToFreeList() to treat the space in between as available.
uint64_t first_sector = super_device().first_logical_sector;
uint64_t last_sector = super_device().size / LP_SECTOR_SIZE;
extents.emplace_back(first_sector, first_sector);
extents.emplace_back(last_sector, last_sector);
std::sort(extents.begin(), extents.end());
ExtentsToFreeList(extents, &free_regions);
return free_regions;
}
bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t aligned_size) {
PartitionGroup* group = FindGroup(partition->group_name());
CHECK(group);
// Figure out how much we need to allocate, and whether our group has
// enough space remaining.
uint64_t space_needed = aligned_size - partition->size();
if (group->maximum_size() > 0) {
uint64_t group_size = TotalSizeOfGroup(group);
if (group_size >= group->maximum_size() ||
group->maximum_size() - group_size < space_needed) {
LERROR << "Partition " << partition->name() << " is part of group " << group->name()
<< " which does not have enough space free (" << space_needed << "requested, "
<< group_size << " used out of " << group->maximum_size();
return false;
}
}
uint64_t sectors_needed = space_needed / LP_SECTOR_SIZE;
DCHECK(sectors_needed * LP_SECTOR_SIZE == space_needed);
std::vector<Interval> free_regions = GetFreeRegions();
const uint64_t sectors_per_block = geometry_.logical_block_size / LP_SECTOR_SIZE;
CHECK_NE(sectors_per_block, 0);
CHECK(sectors_needed % sectors_per_block == 0);
// Find gaps that we can use for new extents. Note we store new extents in a
// temporary vector, and only commit them if we are guaranteed enough free
// space.
std::vector<std::unique_ptr<LinearExtent>> new_extents;
for (auto& region : free_regions) {
if (region.length() % sectors_per_block != 0) {
// This should never happen, because it would imply that we
// once allocated an extent that was not a multiple of the
// block size. That extent would be rejected by DM_TABLE_LOAD.
LERROR << "Region " << region.start << ".." << region.end
<< " is not a multiple of the block size, " << sectors_per_block;
// If for some reason the final region is mis-sized we still want
// to be able to grow partitions. So just to be safe, round the
// region down to the nearest block.
region.end = region.start + (region.length() / sectors_per_block) * sectors_per_block;
if (!region.length()) {
continue;
}
}
uint64_t sectors = std::min(sectors_needed, region.length());
CHECK(sectors % sectors_per_block == 0);
auto extent = std::make_unique<LinearExtent>(sectors, region.start);
new_extents.push_back(std::move(extent));
sectors_needed -= sectors;
if (!sectors_needed) {
break;
}
}
if (sectors_needed) {
LERROR << "Not enough free space to expand partition: " << partition->name();
return false;
}
// Everything succeeded, so commit the new extents.
for (auto& extent : new_extents) {
partition->AddExtent(std::move(extent));
}
return true;
}
void MetadataBuilder::ShrinkPartition(Partition* partition, uint64_t aligned_size) {
partition->ShrinkTo(aligned_size);
}
std::unique_ptr<LpMetadata> MetadataBuilder::Export() {
std::unique_ptr<LpMetadata> metadata = std::make_unique<LpMetadata>();
metadata->header = header_;
metadata->geometry = geometry_;
std::map<std::string, size_t> group_indices;
for (const auto& group : groups_) {
LpMetadataPartitionGroup out = {};
if (group->name().size() > sizeof(out.name)) {
LERROR << "Partition group name is too long: " << group->name();
return nullptr;
}
strncpy(out.name, group->name().c_str(), sizeof(out.name));
out.maximum_size = group->maximum_size();
group_indices[group->name()] = metadata->groups.size();
metadata->groups.push_back(out);
}
// Flatten the partition and extent structures into an LpMetadata, which
// makes it very easy to validate, serialize, or pass on to device-mapper.
for (const auto& partition : partitions_) {
LpMetadataPartition part;
memset(&part, 0, sizeof(part));
if (partition->name().size() > sizeof(part.name)) {
LERROR << "Partition name is too long: " << partition->name();
return nullptr;
}
if (partition->attributes() & ~(LP_PARTITION_ATTRIBUTE_MASK)) {
LERROR << "Partition " << partition->name() << " has unsupported attribute.";
return nullptr;
}
strncpy(part.name, partition->name().c_str(), sizeof(part.name));
part.first_extent_index = static_cast<uint32_t>(metadata->extents.size());
part.num_extents = static_cast<uint32_t>(partition->extents().size());
part.attributes = partition->attributes();
auto iter = group_indices.find(partition->group_name());
if (iter == group_indices.end()) {
LERROR << "Partition " << partition->name() << " is a member of unknown group "
<< partition->group_name();
return nullptr;
}
part.group_index = iter->second;
for (const auto& extent : partition->extents()) {
extent->AddTo(metadata.get());
}
metadata->partitions.push_back(part);
}
metadata->block_devices = block_devices_;
metadata->header.partitions.num_entries = static_cast<uint32_t>(metadata->partitions.size());
metadata->header.extents.num_entries = static_cast<uint32_t>(metadata->extents.size());
metadata->header.groups.num_entries = static_cast<uint32_t>(metadata->groups.size());
metadata->header.block_devices.num_entries =
static_cast<uint32_t>(metadata->block_devices.size());
return metadata;
}
uint64_t MetadataBuilder::AllocatableSpace() const {
return super_device().size - (super_device().first_logical_sector * LP_SECTOR_SIZE);
}
uint64_t MetadataBuilder::UsedSpace() const {
uint64_t size = 0;
for (const auto& partition : partitions_) {
size += partition->size();
}
return size;
}
uint64_t MetadataBuilder::AlignSector(uint64_t sector) const {
// Note: when reading alignment info from the Kernel, we don't assume it
// is aligned to the sector size, so we round up to the nearest sector.
uint64_t lba = sector * LP_SECTOR_SIZE;
uint64_t aligned = AlignTo(lba, super_device().alignment, super_device().alignment_offset);
return AlignTo(aligned, LP_SECTOR_SIZE) / LP_SECTOR_SIZE;
}
bool MetadataBuilder::GetBlockDeviceInfo(BlockDeviceInfo* info) const {
info->size = super_device().size;
info->alignment = super_device().alignment;
info->alignment_offset = super_device().alignment_offset;
info->logical_block_size = geometry_.logical_block_size;
return true;
}
bool MetadataBuilder::UpdateBlockDeviceInfo(const BlockDeviceInfo& device_info) {
if (device_info.size != super_device().size) {
LERROR << "Device size does not match (got " << device_info.size << ", expected "
<< super_device().size << ")";
return false;
}
if (device_info.logical_block_size != geometry_.logical_block_size) {
LERROR << "Device logical block size does not match (got " << device_info.logical_block_size
<< ", expected " << geometry_.logical_block_size << ")";
return false;
}
// The kernel does not guarantee these values are present, so we only
// replace existing values if the new values are non-zero.
if (device_info.alignment) {
super_device().alignment = device_info.alignment;
}
if (device_info.alignment_offset) {
super_device().alignment_offset = device_info.alignment_offset;
}
return true;
}
bool MetadataBuilder::ResizePartition(Partition* partition, uint64_t requested_size) {
// Align the space needed up to the nearest sector.
uint64_t aligned_size = AlignTo(requested_size, geometry_.logical_block_size);
uint64_t old_size = partition->size();
if (aligned_size > old_size) {
if (!GrowPartition(partition, aligned_size)) {
return false;
}
} else if (aligned_size < partition->size()) {
ShrinkPartition(partition, aligned_size);
}
if (partition->size() != old_size) {
LINFO << "Partition " << partition->name() << " will resize from " << old_size
<< " bytes to " << aligned_size << " bytes";
}
return true;
}
std::vector<std::string> MetadataBuilder::ListGroups() const {
std::vector<std::string> names;
for (const auto& group : groups_) {
names.emplace_back(group->name());
}
return names;
}
void MetadataBuilder::RemoveGroupAndPartitions(const std::string& group_name) {
if (group_name == "default") {
// Cannot remove the default group.
return;
}
std::vector<std::string> partition_names;
for (const auto& partition : partitions_) {
if (partition->group_name() == group_name) {
partition_names.emplace_back(partition->name());
}
}
for (const auto& partition_name : partition_names) {
RemovePartition(partition_name);
}
for (auto iter = groups_.begin(); iter != groups_.end(); iter++) {
if ((*iter)->name() == group_name) {
groups_.erase(iter);
break;
}
}
}
} // namespace fs_mgr
} // namespace android