block

Documentation

Overview

Package block provides support for operations on blockdevices.

Index

• Constants
• type Device
  • func NewFromFile(f *os.File) *Device
  • func NewFromPath(path string, opts ...Option) (*Device, error)
  • func (d *Device) Close() error
  • func (d *Device) FastWipe() error
  • func (d *Device) File() *os.File
  • func (d *Device) GetDevNo() (uint64, error)
  • func (d *Device) GetIOSize() (uint, error)
  • func (d *Device) GetKernelLastPartitionNum() (int, error)
  • func (d *Device) GetProperties() (*DeviceProperties, error)
  • func (d *Device) GetSectorSize() uint
  • func (d *Device) GetSize() (uint64, error)
  • func (d *Device) GetWholeDisk() (*Device, error)
  • func (d *Device) IsCD() bool
  • func (d *Device) IsCDNoMedia() bool
  • func (d *Device) IsPrivateDeviceMapper() (bool, error)
  • func (d *Device) IsReadOnly() (bool, error)
  • func (d *Device) IsWholeDisk() (bool, error)
  • func (d *Device) KernelPartitionAdd(no int, start, length uint64) error
  • func (d *Device) KernelPartitionDelete(no int) error
  • func (d *Device) KernelPartitionResize(no int, first, length uint64) error
  • func (d *Device) Lock(exclusive bool) error
  • func (d *Device) RetryLock(ctx context.Context, exclusive bool) error
  • func (d *Device) RetryLockWithTimeout(ctx context.Context, exclusive bool, timeout time.Duration) error
  • func (d *Device) TryLock(exclusive bool) error
  • func (d *Device) Unlock() error
  • func (d *Device) Wipe() (string, error)
  • func (d *Device) WipeRange(start, length uint64) (string, error)
• type DeviceProperties
• type Option
  • func OpenForWrite() Option
• type Options

Constants

const DefaultBlockSize = 512

DefaultBlockSize is the default block size in bytes.

const (
	// FastWipeRange fast wipe block.
	FastWipeRange = 1024 * 1024
)

Types

type Device

type Device struct {
	// contains filtered or unexported fields
}

Device wraps blockdevice operations.

func NewFromFile

func NewFromFile(f *os.File) *Device

NewFromFile returns a new Device from the specified file.

func NewFromPath

func NewFromPath(path string, opts ...Option) (*Device, error)

NewFromPath returns a new Device from the specified path.

func (*Device) Close

func (d *Device) Close() error

Close the device.

No-op if the device was created from a file.

func (*Device) FastWipe

func (d *Device) FastWipe() error

FastWipe the device contents.

This method is much faster than Wipe(), but it doesn't guarantee that device will be zeroed out completely.

func (*Device) File

func (d *Device) File() *os.File

File returns the underlying file.

func (*Device) GetDevNo

func (d *Device) GetDevNo() (uint64, error)

GetDevNo returns the device number of the blockdevice.

func (*Device) GetIOSize

func (d *Device) GetIOSize() (uint, error)

GetIOSize returns blockdevice optimal I/O size in bytes.

func (*Device) GetKernelLastPartitionNum

func (d *Device) GetKernelLastPartitionNum() (int, error)

GetKernelLastPartitionNum returns the maximum partition number in the kernel.

func (*Device) GetProperties

func (d *Device) GetProperties() (*DeviceProperties, error)

GetProperties returns the properties of the block device.

func (*Device) GetSectorSize

func (d *Device) GetSectorSize() uint

GetSectorSize returns blockdevice sector size in bytes.

func (*Device) GetSize

func (d *Device) GetSize() (uint64, error)

GetSize returns blockdevice size in bytes.

func (*Device) GetWholeDisk

func (d *Device) GetWholeDisk() (*Device, error)

GetWholeDisk returns the whole disk for the blockdevice.

If the blockdevice is a whole disk, it returns itself. The returned block device should be closed.

func (*Device) IsCD

func (d *Device) IsCD() bool

IsCD returns true if the blockdevice is a CD-ROM device.

func (*Device) IsCDNoMedia

func (d *Device) IsCDNoMedia() bool

IsCDNoMedia returns true if the blockdevice is a CD-ROM device without media.

func (*Device) IsPrivateDeviceMapper

func (d *Device) IsPrivateDeviceMapper() (bool, error)

IsPrivateDeviceMapper returns true if this is a private device-mapper device.

func (*Device) IsReadOnly

func (d *Device) IsReadOnly() (bool, error)

IsReadOnly returns true if the blockdevice is read-only.

func (*Device) IsWholeDisk

func (d *Device) IsWholeDisk() (bool, error)

IsWholeDisk returns true if the blockdevice is a whole disk.

func (*Device) KernelPartitionAdd

func (d *Device) KernelPartitionAdd(no int, start, length uint64) error

KernelPartitionAdd invokes the BLKPG_ADD_PARTITION ioctl.

func (*Device) KernelPartitionDelete

func (d *Device) KernelPartitionDelete(no int) error

KernelPartitionDelete invokes the BLKPG_DEL_PARTITION ioctl.

func (*Device) KernelPartitionResize

func (d *Device) KernelPartitionResize(no int, first, length uint64) error

KernelPartitionResize invokes the BLKPG_RESIZE_PARTITION ioctl.

func (*Device) Lock

func (d *Device) Lock(exclusive bool) error

Lock (and block until the lock is acquired) for the block device.

func (*Device) RetryLock

func (d *Device) RetryLock(ctx context.Context, exclusive bool) error

RetryLock until the context deadline.

func (*Device) RetryLockWithTimeout

func (d *Device) RetryLockWithTimeout(ctx context.Context, exclusive bool, timeout time.Duration) error

RetryLockWithTimeout retries locking until the timeout.

func (*Device) TryLock

func (d *Device) TryLock(exclusive bool) error

TryLock (and return an error if failed).

func (*Device) Unlock

func (d *Device) Unlock() error

Unlock releases any lock.

func (*Device) Wipe

func (d *Device) Wipe() (string, error)

Wipe the device contents.

In order of availability this tries to perform the following:

• secure discard (secure erase)
• discard with zeros
• zero out via ioctl
• zero out from userland

func (*Device) WipeRange

func (d *Device) WipeRange(start, length uint64) (string, error)

WipeRange the device [start, start+length).

type DeviceProperties

type DeviceProperties struct {
	// Device name, as in 'sda'.
	DeviceName string
	// Model from /sys/block/*/device/model.
	Model string
	// Serial /sys/block/<dev>/device/serial.
	Serial string
	// Modalias /sys/block/<dev>/device/modalias.
	Modalias string
	// WWID /sys/block/<dev>/wwid.
	WWID string
	// UUID /sys/block/<dev>/uuid.
	// BusPath PCI bus path.
	BusPath string
	// SubSystem is the dest path of symlink /sys/block/<dev>/subsystem.
	SubSystem string
	// Transport of the device: SCSI, ata, ahci, nvme, etc.
	Transport string
	// Rotational is true if the device is a rotational disk.
	Rotational bool
}

DeviceProperties contains the properties of a block device.

type Option

type Option func(*Options)

Option is a function that modifies Options.

func OpenForWrite

func OpenForWrite() Option

OpenForWrite opens the device for writing.

type Options

type Options struct {
	Flag int
}

Options for NewFromPath.