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devmapper: rollback thin devices on error

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Signed-off-by: Maksym Pavlenko <makpav@amazon.com>
This commit is contained in:
Maksym Pavlenko 2019-02-21 15:58:31 -08:00
parent adf5c640f4
commit 95f0a4903c
No known key found for this signature in database
GPG Key ID: BDA48CBFE7A0FC14
2 changed files with 111 additions and 36 deletions
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143
snapshots/devmapper/pool_device.go
View File

@ -58,6 +58,7 @@ func NewPoolDevice(ctx context.Context, config *Config) (*PoolDevice, error) {
if _, err := dmsetup.Info(poolPath); err != nil {
return nil, errors.Wrapf(err, "failed to query pool %q", poolPath)
}
return &PoolDevice{
poolName: config.PoolName,
metadata: poolMetaStore,
@ -108,7 +109,7 @@ func (p *PoolDevice) transition(ctx context.Context, deviceName string, tryingSt
// CreateThinDevice creates new devmapper thin-device with given name and size.
// Device ID for thin-device will be allocated from metadata store.
// If allocation successful, device will be activated with /dev/mapper/<deviceName>
func (p *PoolDevice) CreateThinDevice(ctx context.Context, deviceName string, virtualSizeBytes uint64) error {
func (p *PoolDevice) CreateThinDevice(ctx context.Context, deviceName string, virtualSizeBytes uint64) (retErr error) {
info := &DeviceInfo{
Name: deviceName,
Size: virtualSizeBytes,
@ -120,15 +121,46 @@ func (p *PoolDevice) CreateThinDevice(ctx context.Context, deviceName string, vi
return errors.Wrapf(err, "failed to save initial metadata for new thin device %q", deviceName)
}
defer func() {
if retErr == nil {
return
}
// Rollback metadata
retErr = multierror.Append(retErr, p.metadata.RemoveDevice(ctx, info.Name))
}()
// Create thin device
if err := p.transition(ctx, deviceName, Creating, Created, func() error {
if err := p.createDevice(ctx, info); err != nil {
return err
}
defer func() {
if retErr == nil {
return
}
// Rollback creation
retErr = multierror.Append(retErr, p.deleteDevice(ctx, info))
}()
return p.activateDevice(ctx, info)
}
// createDevice creates thin device
func (p *PoolDevice) createDevice(ctx context.Context, info *DeviceInfo) error {
if err := p.transition(ctx, info.Name, Creating, Created, func() error {
return dmsetup.CreateDevice(p.poolName, info.DeviceID)
}); err != nil {
return errors.Wrapf(err, "failed to create new thin device %q (dev: %d)", info.Name, info.DeviceID)
}
// Activate thin device
if err := p.transition(ctx, deviceName, Activating, Activated, func() error {
return nil
}
// activateDevice activates thin device
func (p *PoolDevice) activateDevice(ctx context.Context, info *DeviceInfo) error {
if err := p.transition(ctx, info.Name, Activating, Activated, func() error {
return dmsetup.ActivateDevice(p.poolName, info.Name, info.DeviceID, info.Size, "")
}); err != nil {
return errors.Wrapf(err, "failed to activate new thin device %q (dev: %d)", info.Name, info.DeviceID)
@ -138,20 +170,23 @@ func (p *PoolDevice) CreateThinDevice(ctx context.Context, deviceName string, vi
}
// CreateSnapshotDevice creates and activates new thin-device from parent thin-device (makes snapshot)
func (p *PoolDevice) CreateSnapshotDevice(ctx context.Context, deviceName string, snapshotName string, virtualSizeBytes uint64) error {
func (p *PoolDevice) CreateSnapshotDevice(ctx context.Context, deviceName string, snapshotName string, virtualSizeBytes uint64) (retErr error) {
baseInfo, err := p.metadata.GetDevice(ctx, deviceName)
if err != nil {
return errors.Wrapf(err, "failed to query device metadata for %q", deviceName)
}
// Suspend thin device if it was activated previously
// Suspend thin device if it was activated previously to avoid corruptions
isActivated := p.IsActivated(baseInfo.Name)
if isActivated {
if err := p.transition(ctx, baseInfo.Name, Suspending, Suspended, func() error {
return dmsetup.SuspendDevice(baseInfo.Name)
}); err != nil {
return errors.Wrapf(err, "failed to suspend device %q", baseInfo.Name)
if err := p.suspendDevice(ctx, baseInfo); err != nil {
return err
}
// Resume back base thin device on exit
defer func() {
retErr = multierror.Append(retErr, p.resumeDevice(ctx, baseInfo)).ErrorOrNil()
}()
}
snapInfo := &DeviceInfo{
@ -166,33 +201,63 @@ func (p *PoolDevice) CreateSnapshotDevice(ctx context.Context, deviceName string
return errors.Wrapf(err, "failed to save initial metadata for snapshot %q", snapshotName)
}
defer func() {
if retErr == nil {
return
}
// Rollback metadata
retErr = multierror.Append(retErr, p.metadata.RemoveDevice(ctx, snapInfo.Name))
}()
// Create thin device snapshot
if err := p.createSnapshot(ctx, baseInfo, snapInfo); err != nil {
return err
}
defer func() {
if retErr == nil {
return
}
// Rollback snapshot creation
retErr = multierror.Append(retErr, p.deleteDevice(ctx, snapInfo))
}()
// Activate snapshot device
return p.activateDevice(ctx, snapInfo)
}
func (p *PoolDevice) suspendDevice(ctx context.Context, info *DeviceInfo) error {
if err := p.transition(ctx, info.Name, Suspending, Suspended, func() error {
return dmsetup.SuspendDevice(info.Name)
}); err != nil {
return errors.Wrapf(err, "failed to suspend device %q", info.Name)
}
return nil
}
func (p *PoolDevice) resumeDevice(ctx context.Context, info *DeviceInfo) error {
if err := p.transition(ctx, info.Name, Resuming, Resumed, func() error {
return dmsetup.ResumeDevice(info.Name)
}); err != nil {
return errors.Wrapf(err, "failed to resume device %q", info.Name)
}
return nil
}
func (p *PoolDevice) createSnapshot(ctx context.Context, baseInfo, snapInfo *DeviceInfo) error {
if err := p.transition(ctx, snapInfo.Name, Creating, Created, func() error {
return dmsetup.CreateSnapshot(p.poolName, snapInfo.DeviceID, baseInfo.DeviceID)
}); err != nil {
return errors.Wrapf(err,
"failed to create snapshot %q (dev: %d) from %q (dev: %d, activated: %t)",
"failed to create snapshot %q (dev: %d) from %q (dev: %d)",
snapInfo.Name,
snapInfo.DeviceID,
baseInfo.Name,
baseInfo.DeviceID,
isActivated)
}
if isActivated {
// Resume base thin-device
if err := p.transition(ctx, baseInfo.Name, Resuming, Resumed, func() error {
return dmsetup.ResumeDevice(baseInfo.Name)
}); err != nil {
return errors.Wrapf(err, "failed to resume device %q", deviceName)
}
}
// Activate snapshot
if err := p.transition(ctx, snapInfo.Name, Activating, Activated, func() error {
return dmsetup.ActivateDevice(p.poolName, snapInfo.Name, snapInfo.DeviceID, snapInfo.Size, "")
}); err != nil {
return errors.Wrapf(err, "failed to activate snapshot device %q (dev: %d)", snapInfo.Name, snapInfo.DeviceID)
baseInfo.DeviceID)
}
return nil
@ -221,7 +286,7 @@ func (p *PoolDevice) DeactivateDevice(ctx context.Context, deviceName string, de
// IsActivated returns true if thin-device is activated and not suspended
func (p *PoolDevice) IsActivated(deviceName string) bool {
infos, err := dmsetup.Info(deviceName)
if err != nil || len(infos) == 0 {
if err != nil || len(infos) != 1 {
// Couldn't query device info, device not active
return false
}
@ -244,11 +309,8 @@ func (p *PoolDevice) RemoveDevice(ctx context.Context, deviceName string) error
return err
}
if err := p.transition(ctx, deviceName, Removing, Removed, func() error {
// Send 'delete' message to thin-pool
return dmsetup.DeleteDevice(p.poolName, info.DeviceID)
}); err != nil {
return errors.Wrapf(err, "failed to delete device %q (dev id: %d)", info.Name, info.DeviceID)
if err := p.deleteDevice(ctx, info); err != nil {
return err
}
// Remove record from meta store and free device ID
@ -259,6 +321,17 @@ func (p *PoolDevice) RemoveDevice(ctx context.Context, deviceName string) error
return nil
}
func (p *PoolDevice) deleteDevice(ctx context.Context, info *DeviceInfo) error {
if err := p.transition(ctx, info.Name, Removing, Removed, func() error {
// Send 'delete' message to thin-pool
return dmsetup.DeleteDevice(p.poolName, info.DeviceID)
}); err != nil {
return errors.Wrapf(err, "failed to delete device %q (dev id: %d)", info.Name, info.DeviceID)
}
return nil
}
// RemovePool deactivates all child thin-devices and removes thin-pool device
func (p *PoolDevice) RemovePool(ctx context.Context) error {
deviceNames, err := p.metadata.GetDeviceNames(ctx)

4
snapshots/devmapper/snapshotter.go
View File

@ -310,7 +310,9 @@ func (s *Snapshotter) createSnapshot(ctx context.Context, kind snapshots.Kind, k
}
if err := s.mkfs(ctx, deviceName); err != nil {
return nil, err
// Rollback thin device creation if mkfs failed
return nil, multierror.Append(err,
s.pool.RemoveDevice(ctx, deviceName))
}
} else {
parentDeviceName := s.getDeviceName(snap.ParentIDs[0])