github.com/pritambaral/docker@v1.4.2-0.20150120174542-b2fe1b3dd952/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 var backingFs = "<unknown>" 33 34 func Init(home string, options []string) (graphdriver.Driver, error) { 35 fsMagic, err := graphdriver.GetFSMagic(home) 36 if err != nil { 37 return nil, err 38 } 39 if fsName, ok := graphdriver.FsNames[fsMagic]; ok { 40 backingFs = fsName 41 } 42 43 deviceSet, err := NewDeviceSet(home, true, options) 44 if err != nil { 45 return nil, err 46 } 47 48 if err := mount.MakePrivate(home); err != nil { 49 return nil, err 50 } 51 52 d := &Driver{ 53 DeviceSet: deviceSet, 54 home: home, 55 } 56 57 return graphdriver.NaiveDiffDriver(d), nil 58 } 59 60 func (d *Driver) String() string { 61 return "devicemapper" 62 } 63 64 func (d *Driver) Status() [][2]string { 65 s := d.DeviceSet.Status() 66 67 status := [][2]string{ 68 {"Pool Name", s.PoolName}, 69 {"Pool Blocksize", fmt.Sprintf("%s", units.HumanSize(float64(s.SectorSize)))}, 70 {"Backing Filesystem", backingFs}, 71 {"Data file", s.DataFile}, 72 {"Metadata file", s.MetadataFile}, 73 {"Data Space Used", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Used)))}, 74 {"Data Space Total", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Total)))}, 75 {"Metadata Space Used", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Used)))}, 76 {"Metadata Space Total", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Total)))}, 77 {"Udev Sync Supported", fmt.Sprintf("%v", s.UdevSyncSupported)}, 78 } 79 if len(s.DataLoopback) > 0 { 80 status = append(status, [2]string{"Data loop file", s.DataLoopback}) 81 } 82 if len(s.MetadataLoopback) > 0 { 83 status = append(status, [2]string{"Metadata loop file", s.MetadataLoopback}) 84 } 85 if vStr, err := devicemapper.GetLibraryVersion(); err == nil { 86 status = append(status, [2]string{"Library Version", vStr}) 87 } 88 return status 89 } 90 91 func (d *Driver) Cleanup() error { 92 err := d.DeviceSet.Shutdown() 93 94 if err2 := mount.Unmount(d.home); err == nil { 95 err = err2 96 } 97 98 return err 99 } 100 101 func (d *Driver) Create(id, parent string) error { 102 if err := d.DeviceSet.AddDevice(id, parent); err != nil { 103 return err 104 } 105 106 return nil 107 } 108 109 func (d *Driver) Remove(id string) error { 110 if !d.DeviceSet.HasDevice(id) { 111 // Consider removing a non-existing device a no-op 112 // This is useful to be able to progress on container removal 113 // if the underlying device has gone away due to earlier errors 114 return nil 115 } 116 117 // This assumes the device has been properly Get/Put:ed and thus is unmounted 118 if err := d.DeviceSet.DeleteDevice(id); err != nil { 119 return err 120 } 121 122 mp := path.Join(d.home, "mnt", id) 123 if err := os.RemoveAll(mp); err != nil && !os.IsNotExist(err) { 124 return err 125 } 126 127 return nil 128 } 129 130 func (d *Driver) Get(id, mountLabel string) (string, error) { 131 mp := path.Join(d.home, "mnt", id) 132 133 // Create the target directories if they don't exist 134 if err := os.MkdirAll(mp, 0755); err != nil && !os.IsExist(err) { 135 return "", err 136 } 137 138 // Mount the device 139 if err := d.DeviceSet.MountDevice(id, mp, mountLabel); err != nil { 140 return "", err 141 } 142 143 rootFs := path.Join(mp, "rootfs") 144 if err := os.MkdirAll(rootFs, 0755); err != nil && !os.IsExist(err) { 145 d.DeviceSet.UnmountDevice(id) 146 return "", err 147 } 148 149 idFile := path.Join(mp, "id") 150 if _, err := os.Stat(idFile); err != nil && os.IsNotExist(err) { 151 // Create an "id" file with the container/image id in it to help reconscruct this in case 152 // of later problems 153 if err := ioutil.WriteFile(idFile, []byte(id), 0600); err != nil { 154 d.DeviceSet.UnmountDevice(id) 155 return "", err 156 } 157 } 158 159 return rootFs, nil 160 } 161 162 func (d *Driver) Put(id string) error { 163 err := d.DeviceSet.UnmountDevice(id) 164 if err != nil { 165 log.Errorf("Warning: error unmounting device %s: %s", id, err) 166 } 167 return err 168 } 169 170 func (d *Driver) Exists(id string) bool { 171 return d.DeviceSet.HasDevice(id) 172 }