1 files changed, 46 insertions, 6 deletions

diff --git a/cmd/podman/volumes/prune.go b/cmd/podman/volumes/prune.go
index 0f3ba9ef6..39ad2735b 100644
--- a/cmd/podman/volumes/prune.go
+++ b/cmd/podman/volumes/prune.go
@@ -49,16 +49,46 @@ func init() {
 
 func prune(cmd *cobra.Command, args []string) error {
 	var (
-		pruneOptions = entities.VolumePruneOptions{}
+		pruneOptions  = entities.VolumePruneOptions{}
+		listOptions   = entities.VolumeListOptions{}
+		unusedOptions = entities.VolumeListOptions{}
 	)
 	// Prompt for confirmation if --force is not set
 	force, err := cmd.Flags().GetBool("force")
 	if err != nil {
 		return err
 	}
+	pruneOptions.Filters, err = filters.ParseFilterArgumentsIntoFilters(filter)
 	if !force {
 		reader := bufio.NewReader(os.Stdin)
-		fmt.Println("WARNING! This will remove all volumes not used by at least one container.")
+		fmt.Println("WARNING! This will remove all volumes not used by at least one container. The following volumes will be removed:")
+		if err != nil {
+			return err
+		}
+		listOptions.Filter, err = filters.ParseFilterArgumentsIntoFilters(filter)
+		if err != nil {
+			return err
+		}
+		// filter all the dangling volumes
+		unusedOptions.Filter = make(map[string][]string, 1)
+		unusedOptions.Filter["dangling"] = []string{"true"}
+		unusedVolumes, err := registry.ContainerEngine().VolumeList(context.Background(), unusedOptions)
+		if err != nil {
+			return err
+		}
+		// filter volumes based on user input
+		filteredVolumes, err := registry.ContainerEngine().VolumeList(context.Background(), listOptions)
+		if err != nil {
+			return err
+		}
+		finalVolumes := getIntersection(unusedVolumes, filteredVolumes)
+		if len(finalVolumes) < 1 {
+			fmt.Println("No dangling volumes found")
+			return nil
+		}
+		for _, fv := range finalVolumes {
+			fmt.Println(fv.Name)
+		}
 		fmt.Print("Are you sure you want to continue? [y/N] ")
 		answer, err := reader.ReadString('\n')
 		if err != nil {
@@ -68,13 +98,23 @@ func prune(cmd *cobra.Command, args []string) error {
 			return nil
 		}
 	}
-	pruneOptions.Filters, err = filters.ParseFilterArgumentsIntoFilters(filter)
-	if err != nil {
-		return err
-	}
 	responses, err := registry.ContainerEngine().VolumePrune(context.Background(), pruneOptions)
 	if err != nil {
 		return err
 	}
 	return utils.PrintVolumePruneResults(responses, false)
 }
+
+func getIntersection(a, b []*entities.VolumeListReport) []*entities.VolumeListReport {
+	var intersection []*entities.VolumeListReport
+	hash := make(map[string]bool, len(a))
+	for _, aa := range a {
+		hash[aa.Name] = true
+	}
+	for _, bb := range b {
+		if hash[bb.Name] {
+			intersection = append(intersection, bb)
+		}
+	}
+	return intersection
+}