overlay-volumes: add support for non-volatile upperdir,workdir for anonymous volumes

Similar feature was added for named overlay volumes here: https://github.com/containers/podman/pull/12712
Following PR just mimics similar feature for anonymous volumes.

Often users want their anonymous overlayed volumes to be `non-volatile` in nature
that means that same `upper` dir can be re-used by one or more
containers but overall of nature of volumes still have to be overlay
so work done is still on a overlay not on the actual volume.

Following PR adds support for more advanced options i.e custom `workdir`
and `upperdir` for overlayed volumes. So that users can re-use `workdir`
and `upperdir` across new containers as well.

Usage

```console
podman run -it -v /some/path:/data:O,upperdir=/path/persistant/upper,workdir=/path/persistant/work alpine sh
```

Signed-off-by: Aditya R <arajan@redhat.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/pkg/specgen/volumes.go b/pkg/specgen/volumes.go
index b26666df3..a7a1022b0 100644
--- a/pkg/specgen/volumes.go
+++ b/pkg/specgen/volumes.go
@@ -97,6 +97,8 @@ func GenVolumeMounts(volumeFlag []string) (map[string]spec.Mount, map[string]*Na
 			// This is not a named volume
 			overlayFlag := false
 			chownFlag := false
+			upperDirFlag := false
+			workDirFlag := false
 			for _, o := range options {
 				if o == "O" {
 					overlayFlag = true
@@ -105,8 +107,16 @@ func GenVolumeMounts(volumeFlag []string) (map[string]spec.Mount, map[string]*Na
 					if strings.Contains(joinedOpts, "U") {
 						chownFlag = true
 					}
-
-					if len(options) > 2 || (len(options) == 2 && !chownFlag) {
+					if strings.Contains(joinedOpts, "upperdir") {
+						upperDirFlag = true
+					}
+					if strings.Contains(joinedOpts, "workdir") {
+						workDirFlag = true
+					}
+					if (workDirFlag && !upperDirFlag) || (!workDirFlag && upperDirFlag) {
+						return nil, nil, nil, errors.New("must set both `upperdir` and `workdir`")
+					}
+					if len(options) > 2 && !(len(options) == 3 && upperDirFlag && workDirFlag) || (len(options) == 2 && !chownFlag) {
 						return nil, nil, nil, errors.New("can't use 'O' with other options")
 					}
 				}