libpod/Container.rootFsSize(): use recorded image sizes

In rootFsSize(), instead of calculating the size of the diff for every
layer of the container's base image, ask the storage library for the sum
of the values it recorded when it first wrote those layers.

In a similar fashion, teach rwSize() to use the library's
ContainerSize() method instead of trying to roll its own.

Replace calls to pkg/util.SizeOfPath() with calls to
github.com/containers/storage/pkg/directory.Size(), which does the same
thing.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

libpod/container_internal.go

@@ -55,10 +55,11 @@ const (
 	preCheckpointDir  = "pre-checkpoint"
 )
 
-// rootFsSize gets the size of the container's root filesystem
-// A container FS is split into two parts.  The first is the top layer, a
-// mutable layer, and the rest is the RootFS: the set of immutable layers
-// that make up the image on which the container is based.
+// rootFsSize gets the size of the container, which can be divided notionally
+// into two parts.  The first is the part of its size that can be directly
+// attributed to its base image, if it has one.  The second is the set of
+// changes that the container has had made relative to that base image.  Both
+// parts include some ancillary data, and we count that, too.
 func (c *Container) rootFsSize() (int64, error) {
 	if c.config.Rootfs != "" {
 		return 0, nil
@@ -72,58 +73,33 @@ func (c *Container) rootFsSize() (int64, error) {
 		return 0, err
 	}
 
-	// Ignore the size of the top layer.   The top layer is a mutable RW layer
-	// and is not considered a part of the rootfs
-	rwLayer, err := c.runtime.store.Layer(container.LayerID)
+	size := int64(0)
+	if container.ImageID != "" {
+		size, err = c.runtime.store.ImageSize(container.ImageID)
 		if err != nil {
 			return 0, err
 		}
-	layer, err := c.runtime.store.Layer(rwLayer.Parent)
-	if err != nil {
-		return 0, err
 	}
 
-	size := int64(0)
-	for layer.Parent != "" {
-		layerSize, err := c.runtime.store.DiffSize(layer.Parent, layer.ID)
-		if err != nil {
-			return size, fmt.Errorf("getting diffsize of layer %q and its parent %q: %w", layer.ID, layer.Parent, err)
-		}
-		size += layerSize
-		layer, err = c.runtime.store.Layer(layer.Parent)
-		if err != nil {
-			return 0, err
-		}
-	}
-	// Get the size of the last layer.  Has to be outside of the loop
-	// because the parent of the last layer is "", and lstore.Get("")
-	// will return an error.
-	layerSize, err := c.runtime.store.DiffSize(layer.Parent, layer.ID)
+	layerSize, err := c.runtime.store.ContainerSize(c.ID())
+
 	return size + layerSize, err
 }
 
-// rwSize gets the size of the mutable top layer of the container.
+// rwSize gets the combined size of the writeable layer and any ancillary data
+// for a given container.
 func (c *Container) rwSize() (int64, error) {
 	if c.config.Rootfs != "" {
 		size, err := util.SizeOfPath(c.config.Rootfs)
 		return int64(size), err
 	}
 
-	container, err := c.runtime.store.Container(c.ID())
+	layerSize, err := c.runtime.store.ContainerSize(c.ID())
 	if err != nil {
 		return 0, err
 	}
 
-	// The top layer of a container is
-	// the only readable/writeable layer, all others are immutable.
-	rwLayer, err := c.runtime.store.Layer(container.LayerID)
-	if err != nil {
-		return 0, err
-	}
-
-	// Get the size of the top layer by calculating the size of the diff
-	// between the layer and its parent.
-	return c.runtime.store.DiffSize(rwLayer.Parent, rwLayer.ID)
+	return layerSize, nil
 }
 
 // bundlePath returns the path to the container's root filesystem - where the OCI spec will be

libpod/volume.go

@@ -6,7 +6,7 @@ import (
 	"github.com/containers/podman/v4/libpod/define"
 	"github.com/containers/podman/v4/libpod/lock"
 	"github.com/containers/podman/v4/libpod/plugin"
-	"github.com/containers/podman/v4/pkg/util"
+	"github.com/containers/storage/pkg/directory"
 )
 
 // Volume is a libpod named volume.
@@ -109,7 +109,8 @@ func (v *Volume) Name() string {
 
 // Returns the size on disk of volume
 func (v *Volume) Size() (uint64, error) {
-	return util.SizeOfPath(v.config.MountPoint)
+	size, err := directory.Size(v.config.MountPoint)
+	return uint64(size), err
 }
 
 // Driver retrieves the volume's driver.

pkg/domain/infra/abi/system.go

@@ -18,6 +18,7 @@ import (
 	"github.com/containers/podman/v4/pkg/util"
 	"github.com/containers/podman/v4/utils"
 	"github.com/containers/storage"
+	"github.com/containers/storage/pkg/directory"
 	"github.com/containers/storage/pkg/unshare"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/pflag"
@@ -280,7 +281,7 @@ func (ic *ContainerEngine) SystemDf(ctx context.Context, options entities.System
 		dfImages = append(dfImages, &report)
 	}
 
-	// Get Containers and iterate them
+	// Get containers and iterate over them
 	cons, err := ic.Libpod.GetAllContainers()
 	if err != nil {
 		return nil, err
@@ -322,7 +323,7 @@ func (ic *ContainerEngine) SystemDf(ctx context.Context, options entities.System
 		dfContainers = append(dfContainers, &report)
 	}
 
-	//	Get volumes and iterate them
+	// Get volumes and iterate over them
 	vols, err := ic.Libpod.GetAllVolumes()
 	if err != nil {
 		return nil, err
@@ -330,7 +331,7 @@ func (ic *ContainerEngine) SystemDf(ctx context.Context, options entities.System
 
 	dfVolumes := make([]*entities.SystemDfVolumeReport, 0, len(vols))
 	for _, v := range vols {
-		var reclaimableSize uint64
+		var reclaimableSize int64
 		mountPoint, err := v.MountPoint()
 		if err != nil {
 			return nil, err
@@ -341,7 +342,7 @@ func (ic *ContainerEngine) SystemDf(ctx context.Context, options entities.System
 			// TODO: fix this.
 			continue
 		}
-		volSize, err := util.SizeOfPath(mountPoint)
+		volSize, err := directory.Size(mountPoint)
 		if err != nil {
 			return nil, err
 		}
@@ -355,8 +356,8 @@ func (ic *ContainerEngine) SystemDf(ctx context.Context, options entities.System
 		report := entities.SystemDfVolumeReport{
 			VolumeName:      v.Name(),
 			Links:           len(inUse),
-			Size:            int64(volSize),
-			ReclaimableSize: int64(reclaimableSize),
+			Size:            volSize,
+			ReclaimableSize: reclaimableSize,
 		}
 		dfVolumes = append(dfVolumes, &report)
 	}

pkg/util/utils.go

@@ -3,7 +3,6 @@ package util
 import (
 	"errors"
 	"fmt"
-	"io/fs"
 	"math"
 	"os"
 	"os/user"
@@ -26,6 +25,7 @@ import (
 	"github.com/containers/podman/v4/pkg/namespaces"
 	"github.com/containers/podman/v4/pkg/rootless"
 	"github.com/containers/podman/v4/pkg/signal"
+	"github.com/containers/storage/pkg/directory"
 	"github.com/containers/storage/pkg/idtools"
 	stypes "github.com/containers/storage/types"
 	securejoin "github.com/cyphar/filepath-securejoin"
@@ -618,19 +618,10 @@ func LookupUser(name string) (*user.User, error) {
 
 // SizeOfPath determines the file usage of a given path. it was called volumeSize in v1
 // and now is made to be generic and take a path instead of a libpod volume
+// Deprecated: use github.com/containers/storage/pkg/directory.Size() instead.
 func SizeOfPath(path string) (uint64, error) {
-	var size uint64
-	err := filepath.WalkDir(path, func(path string, d fs.DirEntry, err error) error {
-		if err == nil && !d.IsDir() {
-			info, err := d.Info()
-			if err != nil {
-				return err
-			}
-			size += uint64(info.Size())
-		}
-		return err
-	})
-	return size, err
+	size, err := directory.Size(path)
+	return uint64(size), err
 }
 
 // EncryptConfig translates encryptionKeys into a EncriptionsConfig structure

test/system/320-system-df.bats

@@ -55,18 +55,23 @@ function teardown() {
 Type           | Images    | Containers | Local Volumes
 Total          |         1 |          2 |             0
 Active         |         1 |          1 |             0
-RawSize        | ~12...... |          0 |             0
-RawReclaimable |         0 |          0 |             0
+RawSize        | ~12...... |         !0 |             0
+RawReclaimable |         0 |         !0 |             0
+Reclaimable    |   ~\(0%\) |   ~\(50%\) |       ~\(0%\)
 TotalCount     |         1 |          2 |             0
-Size           |   ~12.*MB |         0B |            0B
+Size           |   ~12.*MB |        !0B |            0B
 '
     while read -a fields; do
         for i in 0 1 2;do
             expect="${fields[$((i+1))]}"
             actual=$(jq -r ".[$i].${fields[0]}" <<<"$results")
 
-            # Do exact-match check, unless the expect term starts with ~
+            # Do exact-match check, unless the expect term starts with ~ or !
             op='='
+            if [[ "$expect" =~ ^\! ]]; then
+                op='!='
+                expect=${expect##\!}
+            fi
             if [[ "$expect" =~ ^~ ]]; then
                 op='=~'
                 expect=${expect##\~}