github.com/titanous/docker@v1.4.1/daemon/graphdriver/devmapper/driver.go (about)

     1  // +build linux
     2  
     3  package devmapper
     4  
     5  import (
     6  	"fmt"
     7  	"io/ioutil"
     8  	"os"
     9  	"path"
    10  
    11  	log "github.com/Sirupsen/logrus"
    12  	"github.com/docker/docker/daemon/graphdriver"
    13  	"github.com/docker/docker/pkg/devicemapper"
    14  	"github.com/docker/docker/pkg/mount"
    15  	"github.com/docker/docker/pkg/units"
    16  )
    17  
    18  func init() {
    19  	graphdriver.Register("devicemapper", Init)
    20  }
    21  
    22  // Placeholder interfaces, to be replaced
    23  // at integration.
    24  
    25  // End of placeholder interfaces.
    26  
    27  type Driver struct {
    28  	*DeviceSet
    29  	home string
    30  }
    31  
    32  func Init(home string, options []string) (graphdriver.Driver, error) {
    33  	deviceSet, err := NewDeviceSet(home, true, options)
    34  	if err != nil {
    35  		return nil, err
    36  	}
    37  
    38  	if err := mount.MakePrivate(home); err != nil {
    39  		return nil, err
    40  	}
    41  
    42  	d := &Driver{
    43  		DeviceSet: deviceSet,
    44  		home:      home,
    45  	}
    46  
    47  	return graphdriver.NaiveDiffDriver(d), nil
    48  }
    49  
    50  func (d *Driver) String() string {
    51  	return "devicemapper"
    52  }
    53  
    54  func (d *Driver) Status() [][2]string {
    55  	s := d.DeviceSet.Status()
    56  
    57  	status := [][2]string{
    58  		{"Pool Name", s.PoolName},
    59  		{"Pool Blocksize", fmt.Sprintf("%s", units.HumanSize(int64(s.SectorSize)))},
    60  		{"Data file", s.DataLoopback},
    61  		{"Metadata file", s.MetadataLoopback},
    62  		{"Data Space Used", fmt.Sprintf("%s", units.HumanSize(int64(s.Data.Used)))},
    63  		{"Data Space Total", fmt.Sprintf("%s", units.HumanSize(int64(s.Data.Total)))},
    64  		{"Metadata Space Used", fmt.Sprintf("%s", units.HumanSize(int64(s.Metadata.Used)))},
    65  		{"Metadata Space Total", fmt.Sprintf("%s", units.HumanSize(int64(s.Metadata.Total)))},
    66  	}
    67  	if vStr, err := devicemapper.GetLibraryVersion(); err == nil {
    68  		status = append(status, [2]string{"Library Version", vStr})
    69  	}
    70  	return status
    71  }
    72  
    73  func (d *Driver) Cleanup() error {
    74  	err := d.DeviceSet.Shutdown()
    75  
    76  	if err2 := mount.Unmount(d.home); err == nil {
    77  		err = err2
    78  	}
    79  
    80  	return err
    81  }
    82  
    83  func (d *Driver) Create(id, parent string) error {
    84  	if err := d.DeviceSet.AddDevice(id, parent); err != nil {
    85  		return err
    86  	}
    87  
    88  	return nil
    89  }
    90  
    91  func (d *Driver) Remove(id string) error {
    92  	if !d.DeviceSet.HasDevice(id) {
    93  		// Consider removing a non-existing device a no-op
    94  		// This is useful to be able to progress on container removal
    95  		// if the underlying device has gone away due to earlier errors
    96  		return nil
    97  	}
    98  
    99  	// This assumes the device has been properly Get/Put:ed and thus is unmounted
   100  	if err := d.DeviceSet.DeleteDevice(id); err != nil {
   101  		return err
   102  	}
   103  
   104  	mp := path.Join(d.home, "mnt", id)
   105  	if err := os.RemoveAll(mp); err != nil && !os.IsNotExist(err) {
   106  		return err
   107  	}
   108  
   109  	return nil
   110  }
   111  
   112  func (d *Driver) Get(id, mountLabel string) (string, error) {
   113  	mp := path.Join(d.home, "mnt", id)
   114  
   115  	// Create the target directories if they don't exist
   116  	if err := os.MkdirAll(mp, 0755); err != nil && !os.IsExist(err) {
   117  		return "", err
   118  	}
   119  
   120  	// Mount the device
   121  	if err := d.DeviceSet.MountDevice(id, mp, mountLabel); err != nil {
   122  		return "", err
   123  	}
   124  
   125  	rootFs := path.Join(mp, "rootfs")
   126  	if err := os.MkdirAll(rootFs, 0755); err != nil && !os.IsExist(err) {
   127  		d.DeviceSet.UnmountDevice(id)
   128  		return "", err
   129  	}
   130  
   131  	idFile := path.Join(mp, "id")
   132  	if _, err := os.Stat(idFile); err != nil && os.IsNotExist(err) {
   133  		// Create an "id" file with the container/image id in it to help reconscruct this in case
   134  		// of later problems
   135  		if err := ioutil.WriteFile(idFile, []byte(id), 0600); err != nil {
   136  			d.DeviceSet.UnmountDevice(id)
   137  			return "", err
   138  		}
   139  	}
   140  
   141  	return rootFs, nil
   142  }
   143  
   144  func (d *Driver) Put(id string) {
   145  	if err := d.DeviceSet.UnmountDevice(id); err != nil {
   146  		log.Errorf("Warning: error unmounting device %s: %s", id, err)
   147  	}
   148  }
   149  
   150  func (d *Driver) Exists(id string) bool {
   151  	return d.DeviceSet.HasDevice(id)
   152  }