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Commit 4b524408 authored by David Anderson's avatar David Anderson
Browse files

fs_mgr: Use libdm for dm-linear devices. 

This removes the custom ioctl code in fs_mgr_dm_linear.cpp in favor of
using libdm.

Bug: 110035986
Test: logical partitions are still created in first-stage init
Change-Id: I941a27ce865aa1bc712b91d8d4c874462e0d11df
parent 2d3e79f5

fs_mgr/fs_mgr_dm_linear.cpp

+52 −84
Original line number Diff line number Diff line
@@ -40,102 +40,70 @@ 
#include <liblp/reader.h>



#include "fs_mgr_priv.h"

#include "fs_mgr_priv_dm_ioctl.h"



namespace android {

namespace fs_mgr {



std::string LogicalPartitionExtent::Serialize() const {

    // Note: we need to include an explicit null-terminator.

    std::string argv =

        android::base::StringPrintf("%s %" PRIu64, block_device_.c_str(), first_sector_);

    argv.push_back(0);

using DeviceMapper = android::dm::DeviceMapper;

using DmTable = android::dm::DmTable;

using DmTarget = android::dm::DmTarget;

using DmTargetZero = android::dm::DmTargetZero;

using DmTargetLinear = android::dm::DmTargetLinear;



    // The kernel expects each target to be aligned.

    size_t spec_bytes = sizeof(struct dm_target_spec) + argv.size();

    size_t padding = ((spec_bytes + 7) & ~7) - spec_bytes;

    for (size_t i = 0; i < padding; i++) {

        argv.push_back(0);

    }



    struct dm_target_spec spec;

    spec.sector_start = logical_sector_;

    spec.length = num_sectors_;

    spec.status = 0;

    strcpy(spec.target_type, "linear");

    spec.next = sizeof(struct dm_target_spec) + argv.size();



    return std::string((char*)&spec, sizeof(spec)) + argv;

}



static bool LoadDmTable(int dm_fd, const LogicalPartition& partition) {

    // Combine all dm_target_spec buffers together.

    std::string target_string;

static bool CreateDmDeviceForPartition(DeviceMapper& dm, const LogicalPartition& partition) {

    DmTable table;

    for (const auto& extent : partition.extents) {

        target_string += extent.Serialize();

        table.AddTarget(std::make_unique<DmTargetLinear>(extent));

    }



    // Allocate the ioctl buffer.

    size_t buffer_size = sizeof(struct dm_ioctl) + target_string.size();

    std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(buffer_size);



    // Initialize the ioctl buffer header, then copy our target specs in.

    struct dm_ioctl* io = reinterpret_cast<struct dm_ioctl*>(buffer.get());

    fs_mgr_dm_ioctl_init(io, buffer_size, partition.name);

    io->target_count = partition.extents.size();

    if (partition.attributes & kPartitionReadonly) {

        io->flags |= DM_READONLY_FLAG;

    }

    memcpy(io + 1, target_string.c_str(), target_string.size());



    if (ioctl(dm_fd, DM_TABLE_LOAD, io)) {

        PERROR << "Failed ioctl() on DM_TABLE_LOAD, partition " << partition.name;

    if (!dm.CreateDevice(partition.name, table)) {

        return false;

    }

    LINFO << "Created device-mapper device: " << partition.name;

    return true;

}



static bool LoadTablesAndActivate(int dm_fd, const LogicalPartition& partition) {

    if (!LoadDmTable(dm_fd, partition)) {

bool CreateLogicalPartitions(const LogicalPartitionTable& table) {

    DeviceMapper& dm = DeviceMapper::Instance();

    for (const auto& partition : table.partitions) {

        if (!CreateDmDeviceForPartition(dm, partition)) {

            LOG(ERROR) << "could not create dm-linear device for partition: " << partition.name;

            return false;

        }



    struct dm_ioctl io;

    return fs_mgr_dm_resume_table(&io, partition.name, dm_fd);

    }



static bool CreateDmDeviceForPartition(int dm_fd, const LogicalPartition& partition) {

    struct dm_ioctl io;

    if (!fs_mgr_dm_create_device(&io, partition.name, dm_fd)) {

        return false;

    }

    if (!LoadTablesAndActivate(dm_fd, partition)) {

        // Remove the device rather than leave it in an inactive state.

        fs_mgr_dm_destroy_device(&io, partition.name, dm_fd);

        return false;

    return true;

}



    LINFO << "Created device-mapper device: " << partition.name;

    return true;

std::unique_ptr<LogicalPartitionTable> LoadPartitionsFromDeviceTree() {

    return nullptr;

}



bool CreateLogicalPartitions(const LogicalPartitionTable& table) {

    android::base::unique_fd dm_fd(open("/dev/device-mapper", O_RDWR));

    if (dm_fd < 0) {

        PLOG(ERROR) << "failed to open /dev/device-mapper";

static bool CreateDmTable(const std::string& block_device, const LpMetadata& metadata,

                          const LpMetadataPartition& partition, DmTable* table) {

    uint64_t sector = 0;

    for (size_t i = 0; i < partition.num_extents; i++) {

        const auto& extent = metadata.extents[partition.first_extent_index + i];

        std::unique_ptr<DmTarget> target;

        switch (extent.target_type) {

            case LP_TARGET_TYPE_ZERO:

                target = std::make_unique<DmTargetZero>(sector, extent.num_sectors);

                break;

            case LP_TARGET_TYPE_LINEAR:

                target = std::make_unique<DmTargetLinear>(sector, extent.num_sectors, block_device,

                                                          extent.target_data);

                break;

            default:

                LOG(ERROR) << "Unknown target type in metadata: " << extent.target_type;

                return false;

        }

    for (const auto& partition : table.partitions) {

        if (!CreateDmDeviceForPartition(dm_fd, partition)) {

            LOG(ERROR) << "could not create dm-linear device for partition: " << partition.name;

        if (!table->AddTarget(std::move(target))) {

            return false;

        }

        sector += extent.num_sectors;

    }

    return true;

    if (partition.attributes & LP_PARTITION_ATTR_READONLY) {

        table->set_readonly(true);

    }



std::unique_ptr<LogicalPartitionTable> LoadPartitionsFromDeviceTree() {

    return nullptr;

    return true;

}



bool CreateLogicalPartitions(const std::string& block_device) {
@@ -146,21 +114,21 @@ bool CreateLogicalPartitions(const std::string& block_device) { 
        return true;

    }



    LogicalPartitionTable table;

    DeviceMapper& dm = DeviceMapper::Instance();

    for (const auto& partition : metadata->partitions) {

        LogicalPartition new_partition;

        new_partition.name = GetPartitionName(partition);

        new_partition.attributes = partition.attributes;

        for (size_t i = 0; i < partition.num_extents; i++) {

            const auto& extent = metadata->extents[partition.first_extent_index + i];

            new_partition.extents.emplace_back(new_partition.num_sectors, extent.target_data,

                                               extent.num_sectors, block_device.c_str());

            new_partition.num_sectors += extent.num_sectors;

        DmTable table;

        if (!CreateDmTable(block_device, *metadata.get(), partition, &table)) {

            return false;

        }

        table.partitions.push_back(new_partition);

        std::string name = GetPartitionName(partition);

        if (!dm.CreateDevice(name, table)) {

            return false;

        }



    return CreateLogicalPartitions(table);

        std::string path;

        dm.GetDmDevicePathByName(partition.name, &path);

        LINFO << "Created logical partition " << name << " on device " << path;

    }

    return true;

}



}  // namespace fs_mgr

fs_mgr/include/fs_mgr_dm_linear.h

+5 −38
Original line number Diff line number Diff line
@@ -26,53 +26,20 @@ 
#define __CORE_FS_MGR_DM_LINEAR_H



#include <stdint.h>



#include <memory>

#include <string>

#include <vector>



#include <libdm/dm.h>

#include <liblp/metadata_format.h>



namespace android {

namespace fs_mgr {



static const uint32_t kPartitionReadonly = 0x1;



class LogicalPartitionExtent {

  public:

    LogicalPartitionExtent() : logical_sector_(0), first_sector_(0), num_sectors_(0) {}

    LogicalPartitionExtent(uint64_t logical_sector, uint64_t first_sector, uint64_t num_sectors,

                           const std::string& block_device)

        : logical_sector_(logical_sector),

          first_sector_(first_sector),

          num_sectors_(num_sectors),

          block_device_(block_device) {}



    // Return a string containing the dm_target_spec buffer needed to use this

    // extent in a device-mapper table.

    std::string Serialize() const;



    const std::string& block_device() const { return block_device_; }



  private:

    // Logical sector this extent represents in the presented block device.

    // This is equal to the previous extent's logical sector plus the number

    // of sectors in that extent. The first extent always starts at 0.

    uint64_t logical_sector_;

    // First 512-byte sector of this extent, on the source block device.

    uint64_t first_sector_;

    // Number of 512-byte sectors.

    uint64_t num_sectors_;

    // Target block device.

    std::string block_device_;

};



struct LogicalPartition {

    LogicalPartition() : attributes(0), num_sectors(0) {}



    std::string name;

    uint32_t attributes;

    // Number of 512-byte sectors total.

    uint64_t num_sectors;

    // List of extents.

    std::vector<LogicalPartitionExtent> extents;

    std::vector<android::dm::DmTargetLinear> extents;

};



struct LogicalPartitionTable {

fs_mgr/libdm/include/libdm/dm_target.h

+1 −0
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ class DmTargetLinear final : public DmTarget { 


    std::string name() const override { return "linear"; }

    std::string GetParameterString() const override;

    const std::string& block_device() const { return block_device_; }



  private:

    std::string block_device_;