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Commit e1c0744c authored by David Anderson's avatar David Anderson
Browse files

libdm: Implement LoadTableAndActivate. 

This change implements DeviceMapper::LoadTableAndActivate by serializing
the given DmTable and issuing DM_TABLE_LOAD and DM_DEV_SUSPEND ioctls.
In addition, this makes the CreateDevice() method private, and
introduces a separate method for creating a device and loading a table
as a single operation. This will obviate the need for separate inactive
device cleanup logic later.

Note that this change does not yet implement DmTable::Serialize().

Bug: 110035986
Test: N/A
Change-Id: Ic8affe591db4930ce672b00db989978b57ca8cbf
parent b1a834ec

fs_mgr/libdm/dm.cpp

+31 −2
Original line number Original line Diff line number Diff line
@@ -94,9 +94,38 @@ DmDeviceState DeviceMapper::state(const std::string& /* name */) const { 
    return DmDeviceState::INVALID;

    return DmDeviceState::INVALID;

}

}





bool DeviceMapper::LoadTableAndActivate(const std::string& /* name */, const DmTable& /* table */) {

bool DeviceMapper::CreateDevice(const std::string& name, const DmTable& table) {

    if (!CreateDevice(name)) {

        return false;

        return false;

    }

    }

    if (!LoadTableAndActivate(name, table)) {

        DeleteDevice(name);

        return false;

    }

    return true;

}



bool DeviceMapper::LoadTableAndActivate(const std::string& name, const DmTable& table) {

    std::string ioctl_buffer(sizeof(struct dm_ioctl), 0);

    ioctl_buffer += table.Serialize();



    struct dm_ioctl* io = reinterpret_cast<struct dm_ioctl*>(&ioctl_buffer[0]);

    InitIo(io, name);

    io->data_size = ioctl_buffer.size();

    io->data_start = sizeof(struct dm_ioctl);

    io->target_count = static_cast<uint32_t>(table.num_targets());

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

        PLOG(ERROR) << "DM_TABLE_LOAD failed";

        return false;

    }



    InitIo(io, name);

    if (ioctl(fd_, DM_DEV_SUSPEND, io)) {

        PLOG(ERROR) << "DM_TABLE_SUSPEND resume failed";

        return false;

    }

    return true;

}





// Reads all the available device mapper targets and their corresponding

// Reads all the available device mapper targets and their corresponding

// versions from the kernel and returns in a vector

// versions from the kernel and returns in a vector

fs_mgr/libdm/dm_table.cpp

+2 −2
Original line number Original line Diff line number Diff line
@@ -34,8 +34,8 @@ bool DmTable::valid() const { 
    return true;

    return true;

}

}





uint64_t DmTable::size() const {

uint64_t DmTable::num_sectors() const {

    return valid() ? size_ : 0;

    return valid() ? num_sectors_ : 0;

}

}





// Returns a string represnetation of the table that is ready to be passed

// Returns a string represnetation of the table that is ready to be passed

fs_mgr/libdm/include/libdm/dm.h

+14 −11
Original line number Original line Diff line number Diff line
@@ -69,14 +69,6 @@ class DeviceMapper final { 
        uint64_t dev_;

        uint64_t dev_;

    };

    };





    // Creates a device mapper device with given name.

    // Return 'true' on success and 'false' on failure to

    // create OR if a device mapper device with the same name already

    // exists.

    // TODO(b/110035986): Make this method private and to be only

    // called through LoadTableAndActivate() below.

    bool CreateDevice(const std::string& name);



    // Removes a device mapper device with the given name.

    // Removes a device mapper device with the given name.

    // Returns 'true' on success, false otherwise.

    // Returns 'true' on success, false otherwise.

    bool DeleteDevice(const std::string& name);

    bool DeleteDevice(const std::string& name);
@@ -90,9 +82,14 @@ class DeviceMapper final { 
    // One of INVALID, SUSPENDED or ACTIVE.

    // One of INVALID, SUSPENDED or ACTIVE.

    DmDeviceState state(const std::string& name) const;

    DmDeviceState state(const std::string& name) const;





    // Loads the device mapper table from parameter into the underlying

    // Creates a device, loads the given table, and activates it. If the device

    // device mapper device with given name and activate / resumes the device in the process.

    // is not able to be activated, it is destroyed, and false is returned.

    // If a device mapper device with the 'name', doesn't exist, it will be created.

    bool CreateDevice(const std::string& name, const DmTable& table);



    // Loads the device mapper table from parameter into the underlying device

    // mapper device with given name and activate / resumes the device in the

    // process. A device with the given name must already exist.

    //

    // Returns 'true' on success, false otherwise.

    // Returns 'true' on success, false otherwise.

    bool LoadTableAndActivate(const std::string& name, const DmTable& table);

    bool LoadTableAndActivate(const std::string& name, const DmTable& table);
@@ -140,6 +137,12 @@ class DeviceMapper final { 
        }

        }

    }

    }





    // Creates a device mapper device with given name.

    // Return 'true' on success and 'false' on failure to

    // create OR if a device mapper device with the same name already

    // exists.

    bool CreateDevice(const std::string& name);



    int fd_;

    int fd_;

    // Non-copyable & Non-movable

    // Non-copyable & Non-movable

    DeviceMapper(const DeviceMapper&) = delete;

    DeviceMapper(const DeviceMapper&) = delete;

fs_mgr/libdm/include/libdm/dm_table.h

+6 −3
Original line number Original line Diff line number Diff line
@@ -30,7 +30,7 @@ namespace dm { 




class DmTable {

class DmTable {

  public:

  public:

    DmTable() : size_(0){};

    DmTable() : num_sectors_(0){};





    // Adds a target to the device mapper table for a range specified in the target object.

    // Adds a target to the device mapper table for a range specified in the target object.

    // The function will return 'true' if the target was successfully added and doesn't overlap with

    // The function will return 'true' if the target was successfully added and doesn't overlap with
@@ -48,9 +48,12 @@ class DmTable { 
    // table is malformed.

    // table is malformed.

    bool valid() const;

    bool valid() const;





    // Returns the toatl number of targets.

    size_t num_targets() const { return targets_.size(); }



    // Returns the total size represented by the table in terms of number of 512-byte sectors.

    // Returns the total size represented by the table in terms of number of 512-byte sectors.

    // NOTE: This function will overlook if there are any gaps in the targets added in the table.

    // NOTE: This function will overlook if there are any gaps in the targets added in the table.

    uint64_t size() const;

    uint64_t num_sectors() const;





    // Returns the string represntation of the table that is ready to be passed into the kernel

    // Returns the string represntation of the table that is ready to be passed into the kernel

    // as part of the DM_TABLE_LOAD ioctl.

    // as part of the DM_TABLE_LOAD ioctl.
@@ -66,7 +69,7 @@ class DmTable { 




    // Total size in terms of # of sectors, as calculated by looking at the last and the first

    // Total size in terms of # of sectors, as calculated by looking at the last and the first

    // target in 'target_'.

    // target in 'target_'.

    uint64_t size_;

    uint64_t num_sectors_;

};

};





}  // namespace dm

}  // namespace dm

fs_mgr/tools/dmctl.cpp

+4 −1
Original line number Original line Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <vector>

#include <vector>





using DeviceMapper = ::android::dm::DeviceMapper;

using DeviceMapper = ::android::dm::DeviceMapper;

using DmTable = ::android::dm::DmTable;

using DmTarget = ::android::dm::DmTarget;

using DmTarget = ::android::dm::DmTarget;

using DmBlockDevice = ::android::dm::DeviceMapper::DmBlockDevice;

using DmBlockDevice = ::android::dm::DeviceMapper::DmBlockDevice;
@@ -53,9 +54,11 @@ static int DmCreateCmdHandler(int argc, char** argv) { 
        return -EINVAL;

        return -EINVAL;

    }

    }





    DmTable table;



    std::string name = argv[0];

    std::string name = argv[0];

    DeviceMapper& dm = DeviceMapper::Instance();

    DeviceMapper& dm = DeviceMapper::Instance();

    if (!dm.CreateDevice(name)) {

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

        std::cerr << "Failed to create device-mapper device with name: " << name << std::endl;

        std::cerr << "Failed to create device-mapper device with name: " << name << std::endl;

        return -EIO;

        return -EIO;

    }

    }