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devmapper: Find a free device Id to use for device creation

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Finally, we seem to have all the bits to keep track of all used device
Ids and find a free device Id to use when creating a  new device. Start
using it.

Ideally we should completely move away from retry logic when pool returns
-EEXISTS. For now I have retained that logic and I simply output a warning.
When things are stable, we should be able to get rid of it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
This commit is contained in:
Vivek Goyal 2014-12-03 13:06:43 -05:00 committed by root
parent 14d0dd855e
commit e28a419e11
1 changed files with 46 additions and 8 deletions
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54
daemon/graphdriver/devmapper/deviceset.go
View file

@ -500,21 +500,41 @@ func (devices *DeviceSet) incNextDeviceId() {
devices.NextDeviceId = (devices.NextDeviceId + 1) & MaxDeviceId
}
func (devices *DeviceSet) getNextDeviceId() int {
func (devices *DeviceSet) getNextFreeDeviceId() (int, error) {
devices.incNextDeviceId()
return devices.NextDeviceId
for i := 0; i <= MaxDeviceId; i++ {
if devices.isDeviceIdFree(devices.NextDeviceId) {
devices.markDeviceIdUsed(devices.NextDeviceId)
return devices.NextDeviceId, nil
}
devices.incNextDeviceId()
}
return 0, fmt.Errorf("Unable to find a free device Id")
}
func (devices *DeviceSet) createRegisterDevice(hash string) (*DevInfo, error) {
deviceId := devices.getNextDeviceId()
deviceId, err := devices.getNextFreeDeviceId()
if err != nil {
return nil, err
}
for {
if err := devicemapper.CreateDevice(devices.getPoolDevName(), deviceId); err != nil {
if devicemapper.DeviceIdExists(err) {
// Device Id already exists. Try a new one.
deviceId = devices.getNextDeviceId()
// Device Id already exists. This should not
// happen. Now we have a mechianism to find
// a free device Id. So something is not right.
// Give a warning and continue.
log.Errorf("Warning: Device Id %d exists in pool but it is supposed to be unused", deviceId)
deviceId, err = devices.getNextFreeDeviceId()
if err != nil {
return nil, err
}
continue
}
log.Debugf("Error creating device: %s", err)
devices.markDeviceIdFree(deviceId)
return nil, err
}
break
@ -525,27 +545,41 @@ func (devices *DeviceSet) createRegisterDevice(hash string) (*DevInfo, error) {
info, err := devices.registerDevice(deviceId, hash, devices.baseFsSize, transactionId)
if err != nil {
_ = devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
return nil, err
}
if err := devices.updatePoolTransactionId(); err != nil {
devices.unregisterDevice(deviceId, hash)
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
return nil, err
}
return info, nil
}
func (devices *DeviceSet) createRegisterSnapDevice(hash string, baseInfo *DevInfo) error {
deviceId := devices.getNextDeviceId()
deviceId, err := devices.getNextFreeDeviceId()
if err != nil {
return err
}
for {
if err := devicemapper.CreateSnapDevice(devices.getPoolDevName(), deviceId, baseInfo.Name(), baseInfo.DeviceId); err != nil {
if devicemapper.DeviceIdExists(err) {
// Device Id already exists. Try a new one.
deviceId = devices.getNextDeviceId()
// Device Id already exists. This should not
// happen. Now we have a mechianism to find
// a free device Id. So something is not right.
// Give a warning and continue.
log.Errorf("Warning: Device Id %d exists in pool but it is supposed to be unused", deviceId)
deviceId, err = devices.getNextFreeDeviceId()
if err != nil {
return err
}
continue
}
log.Debugf("Error creating snap device: %s", err)
devices.markDeviceIdFree(deviceId)
return err
}
break
@ -554,6 +588,7 @@ func (devices *DeviceSet) createRegisterSnapDevice(hash string, baseInfo *DevInf
transactionId := devices.allocateTransactionId()
if _, err := devices.registerDevice(deviceId, hash, baseInfo.Size, transactionId); err != nil {
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
log.Debugf("Error registering device: %s", err)
return err
}
@ -561,6 +596,7 @@ func (devices *DeviceSet) createRegisterSnapDevice(hash string, baseInfo *DevInf
if err := devices.updatePoolTransactionId(); err != nil {
devices.unregisterDevice(deviceId, hash)
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
return err
}
return nil
@ -966,6 +1002,8 @@ func (devices *DeviceSet) deleteDevice(info *DevInfo) error {
return err
}
devices.markDeviceIdFree(info.DeviceId)
return nil
}