Page History

// RollbackCmd - snapshot rollback command
message RollbackCmd {
	string snpshot_uuid = 1;
	string volume_uuid = 2;
	DeviceOpsCmd rollback = 3;
}

// SnapshotConfig describes a snapshot for a specific logical
// volume that must exist on the device. It has a required field
// volume_uuid for which it was created and UUID for snapshot name in ZFS.
message SnapshotConfig {
	// The real name of the snapshot in ZFS. It is the link between
	// the command and the response to the command. It is assumed
	// that the field will always be filled with a unique value
	// that the controller will generate.
	string uuid = 1;
	// Display name (User-friendly name). This name does not affect
	// the snapshot properties in ZFS in any way.
	// Can be filled on the controller side.
	// If a snapshot has already been created and this field has changed,
	// it can be assumed that the friendly name for this snapshot has
	// been renamed on the controller side.
	string display_name = 2;
	// Volume ID of the volume this snapshot belongs to. The field is
	// required for all messages. Must always be filled in on the
	// controller side before sending to create snapshot command.
	string volume_uuid = 3;
	// The command for the snapshot rollback operation.
	// It should also be taken that the rollback cmd
	// to snapshot k will implicitly automatically delete
	// all snapshots from k+1 to N, If the deletion of snapshots
	// from k+1 to N was not initiated by the controller before
	// the rollback cmd
	RollbackCmd rollback = 4;
}

//
// If the counter in the DeviceOpsCmd is different, it will cause a
// rollback operation.
//
// The fields from RollbackCmd (snapshot_uuid, volume_uuid) will
// always match the fields from the SnapshotConfig (snapshot_uuid, volume_uuid)
// to which RollbackCmd belongs.
//
// For example: take the situation where the controller requests one or more
// snapshots (uuid=1 for volume_uuid=X, then add a second SnapshotCmd
// with uuid=2 for volume_uuid=X), and then later it send a RollbackCmd with
// snapshot_uuid=1
//
// In this case, the following will happen:
// It is assumed that the RollbackCmd message cannot come separately from
// the configuration, and will always be part of the SnapshotConfig for
// every snapshot. And we will always receive from the controller a complete
// list of SnapshotConfig for all snapshots that the controller knows about.
// Then after the snapshot with uuid=2 has been created, we can also get
// a SnapshotConfig for uuid=1, where the counter in RollbackCmd will be +1.
// Thus, we will roll back to the state of the logical volume at the time
// of the snapshot with uuid=1, and the snapshot with uuid=2 will be marked
// in the info message how IMPLICITLY_DELETED (If the controller did not take
// care of deleting the snapshot with uuid=2 before the rollback command).
message RollbackCmd {
  	// UUID of the snapshot to rollback to. Is the snapshot_uuid
   	// from the SnapshotConfig and the real and unique name of the
  	// snapshot in ZFS. This is the rollback target for volume_uuid.
   	string snapshot_uuid = 1;
   	string volume_uuid = 2;    // UUID of the volume to rollback
	DeviceOpsCmd rollback = 3; // Counter for rollback
}

// SnapshotConfig describes a snapshot for a specific logical
// volume that must exist on the device. It has a required field
// volume_uuid for which it was created and UUID for snapshot name in ZFS.
message SnapshotConfig {
   // The real name of the snapshot in ZFS. It is the link between
   // the command and the response to the command. It is assumed
   // that the field will always be filled with a unique value
   // that the controller will generate.
   string snapshot_uuid = 1;
   // Display name (User-friendly name). This name does not affect
   // the snapshot properties in ZFS in any way.
   // Can be filled on the controller side.
   // If a snapshot has already been created and this field has changed,
   // it can be assumed that the friendly name for this snapshot has
   // been renamed on the controller side.
   string display_name = 2;
   // Volume ID of the volume this snapshot belongs to. The field is
   // required for all messages. Must always be filled in on the
   // controller side before sending to create snapshot command.
   string volume_uuid = 3;
   // An "optional" snapshot rollback operation command, because
   // not all SnapshotConfig require a rollback command
   // If the RollbackCmd message is not enabled, it means that
   // a rollback is not requested. If RollbackCmd is enabled in this
   // config, then a rollback has been requested, and also the counter
   // in RollbackCmd will be checked.
   // It should also be taken that the rollback cmd
   // to snapshot k will implicitly automatically delete
   // all snapshots from k+1 to N, If the deletion of snapshots
   // from k+1 to N was not initiated by the controller before
   // the rollback cmd.
   RollbackCmd rollback = 4;
}

// Snapshot states
enum ZSnapshotState {
	Z_SNAPSHOT_STATE_UNSPECIFIED = 0;
	// This state is used when a snapshot is in the process of being
	// created or an error occurred during the first attempt to create it.
	// (For example, the operation was delayed)
	Z_SNAPSHOT_STATE_CREATING = 1;
	// This state is used when the snapshot has been successfully created.
	Z_SNAPSHOT_STATE_CREATED = 2;
	// This state is used when the snapshot is pending deletion or
	// the first deletion attempt was not successful.
	Z_SNAPSHOT_STATE_DELETING = 3;
	// This state is used to send information to the controller about a
	// snapshot that was implicitly deleted after a rollback snapshot
	// or volume delete command.
	Z_SNAPSHOT_STATE_IMPLICITLY_DELETED = 4;
}

// ZInfoSnapshot - Information about snapshot in zfs for zvol
message ZInfoSnapshot {
	uint64 creation_time = 1; // In seconds
	string uuid = 2; // link a command and a response. Is the real name of the snapshot in ZFS
	string volume_uuid = 3; // Volume ID of the volume this snapshot belongs to.
	string display_name = 4; // Ex: "Tuesday" or creation time (User-friendly name)
	bool encryption = 5;
	ZSnapshotState current_state = 6; // Displays the current state of the snapshot
	string error_msg = 7; // Ops error
	uint32 rollback_cmd_counter = 8; // Counter for rollback cmd
	uint64 rollback_time_last_op = 9; // The time when the last rollback operation was performed for this snapshot
}