github.com/sbward/docker@v1.4.2-0.20150114010528-c9dab702bed3/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(float64(s.SectorSize)))},
    60  		{"Data file", s.DataFile},
    61  		{"Metadata file", s.MetadataFile},
    62  		{"Data Space Used", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Used)))},
    63  		{"Data Space Total", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Total)))},
    64  		{"Metadata Space Used", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Used)))},
    65  		{"Metadata Space Total", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Total)))},
    66  	}
    67  	if len(s.DataLoopback) > 0 {
    68  		status = append(status, [2]string{"Data loop file", s.DataLoopback})
    69  	}
    70  	if len(s.MetadataLoopback) > 0 {
    71  		status = append(status, [2]string{"Metadata loop file", s.MetadataLoopback})
    72  	}
    73  	if vStr, err := devicemapper.GetLibraryVersion(); err == nil {
    74  		status = append(status, [2]string{"Library Version", vStr})
    75  	}
    76  	return status
    77  }
    78  
    79  func (d *Driver) Cleanup() error {
    80  	err := d.DeviceSet.Shutdown()
    81  
    82  	if err2 := mount.Unmount(d.home); err == nil {
    83  		err = err2
    84  	}
    85  
    86  	return err
    87  }
    88  
    89  func (d *Driver) Create(id, parent string) error {
    90  	if err := d.DeviceSet.AddDevice(id, parent); err != nil {
    91  		return err
    92  	}
    93  
    94  	return nil
    95  }
    96  
    97  func (d *Driver) Remove(id string) error {
    98  	if !d.DeviceSet.HasDevice(id) {
    99  		// Consider removing a non-existing device a no-op
   100  		// This is useful to be able to progress on container removal
   101  		// if the underlying device has gone away due to earlier errors
   102  		return nil
   103  	}
   104  
   105  	// This assumes the device has been properly Get/Put:ed and thus is unmounted
   106  	if err := d.DeviceSet.DeleteDevice(id); err != nil {
   107  		return err
   108  	}
   109  
   110  	mp := path.Join(d.home, "mnt", id)
   111  	if err := os.RemoveAll(mp); err != nil && !os.IsNotExist(err) {
   112  		return err
   113  	}
   114  
   115  	return nil
   116  }
   117  
   118  func (d *Driver) Get(id, mountLabel string) (string, error) {
   119  	mp := path.Join(d.home, "mnt", id)
   120  
   121  	// Create the target directories if they don't exist
   122  	if err := os.MkdirAll(mp, 0755); err != nil && !os.IsExist(err) {
   123  		return "", err
   124  	}
   125  
   126  	// Mount the device
   127  	if err := d.DeviceSet.MountDevice(id, mp, mountLabel); err != nil {
   128  		return "", err
   129  	}
   130  
   131  	rootFs := path.Join(mp, "rootfs")
   132  	if err := os.MkdirAll(rootFs, 0755); err != nil && !os.IsExist(err) {
   133  		d.DeviceSet.UnmountDevice(id)
   134  		return "", err
   135  	}
   136  
   137  	idFile := path.Join(mp, "id")
   138  	if _, err := os.Stat(idFile); err != nil && os.IsNotExist(err) {
   139  		// Create an "id" file with the container/image id in it to help reconscruct this in case
   140  		// of later problems
   141  		if err := ioutil.WriteFile(idFile, []byte(id), 0600); err != nil {
   142  			d.DeviceSet.UnmountDevice(id)
   143  			return "", err
   144  		}
   145  	}
   146  
   147  	return rootFs, nil
   148  }
   149  
   150  func (d *Driver) Put(id string) error {
   151  	err := d.DeviceSet.UnmountDevice(id)
   152  	if err != nil {
   153  		log.Errorf("Warning: error unmounting device %s: %s", id, err)
   154  	}
   155  	return err
   156  }
   157  
   158  func (d *Driver) Exists(id string) bool {
   159  	return d.DeviceSet.HasDevice(id)
   160  }