incusd/storage/btrfs: Report migration progress from receiver

Closes #676

Signed-off-by: Stéphane Graber <stgraber@stgraber.org>

internal/server/storage/drivers/driver_btrfs_utils.go

@@ -603,13 +603,22 @@ func (d *btrfs) loadOptimizedBackupHeader(r io.ReadSeeker, mountPath string) (*B
 }
 
 // receiveSubVolume receives a subvolume from an io.Reader into the receivePath and returns the path to the received subvolume.
-func (d *btrfs) receiveSubVolume(r io.Reader, receivePath string) (string, error) {
+func (d *btrfs) receiveSubVolume(r io.Reader, receivePath string, tracker *ioprogress.ProgressTracker) (string, error) {
 	files, err := os.ReadDir(receivePath)
 	if err != nil {
 		return "", fmt.Errorf("Failed listing contents of %q: %w", receivePath, err)
 	}
 
-	err = subprocess.RunCommandWithFds(context.TODO(), r, nil, "btrfs", "receive", "-e", receivePath)
+	// Setup progress tracker.
+	var stdin io.Reader = r
+	if tracker != nil {
+		stdin = &ioprogress.ProgressReader{
+			Reader:  r,
+			Tracker: tracker,
+		}
+	}
+
+	err = subprocess.RunCommandWithFds(context.TODO(), stdin, nil, "btrfs", "receive", "-e", receivePath)
 	if err != nil {
 		return "", err
 	}

internal/server/storage/drivers/driver_btrfs_volumes.go

@@ -258,7 +258,7 @@ func (d *btrfs) CreateVolumeFromBackup(vol Volume, srcBackup backup.Info, srcDat
 			}
 
 			if hdr.Name == srcFile {
-				subVolRecvPath, err := d.receiveSubVolume(tr, targetPath)
+				subVolRecvPath, err := d.receiveSubVolume(tr, targetPath, nil)
 				if err != nil {
 					return "", err
 				}
@@ -628,6 +628,12 @@ func (d *btrfs) createVolumeFromMigrationOptimized(vol Volume, conn io.ReadWrite
 	receiveVolume := func(v Volume, receivePath string) error {
 		_, snapName, _ := api.GetParentAndSnapshotName(v.name)
 
+		// Setup progress tracking.
+		var wrapper *ioprogress.ProgressTracker
+		if volTargetArgs.TrackProgress {
+			wrapper = localMigration.ProgressTracker(op, "fs_progress", v.name)
+		}
+
 		for _, subVol := range subvolumes {
 			if subVol.Snapshot != snapName {
 				continue // Skip any subvolumes that dont belong to our volume (empty for main).
@@ -643,7 +649,7 @@ func (d *btrfs) createVolumeFromMigrationOptimized(vol Volume, conn io.ReadWrite
 			subVolTargetPath := filepath.Join(v.MountPath(), subVol.Path)
 			d.logger.Debug("Receiving volume", logger.Ctx{"name": v.name, "receivePath": receivePath, "path": subVolTargetPath})
 
-			subVolRecvPath, err := d.receiveSubVolume(conn, receivePath)
+			subVolRecvPath, err := d.receiveSubVolume(conn, receivePath, wrapper)
 			if err != nil {
 				return err
 			}