compat/api: honor VolumeOptions.Subpath for HostConfig.Mounts

fixes: #27171
Signed-off-by: Jonathan Caicedo <jonathan@jcaicedo.com>

pkg/api/handlers/compat/containers_create.go

@@ -255,6 +255,9 @@ func cliOpts(cc handlers.CreateContainerConfig, rtc *config.Config) (*entities.C
 				addField(&builder, "tmpfs-mode", strconv.FormatUint(uint64(m.TmpfsOptions.Mode), 8))
 			}
 		case mount.TypeVolume:
+			if m.VolumeOptions != nil {
+				addField(&builder, "subpath", m.VolumeOptions.Subpath)
+			}
 			// All current VolumeOpts are handled above
 			// See vendor/github.com/containers/common/pkg/parse/parse.go:ValidateVolumeOpts()
 		}

test/apiv2/44-mounts.at

@@ -37,3 +37,24 @@ t POST libpod/containers/create \
   500 \
   .cause="invalid mount option" \
   .message~"the 'noatime' option is only allowed with tmpfs mounts"
+
+# Compat API: HostConfig.Mounts.VolumeOptions.Subpath mounts only the selected volume subdirectory
+subpath_vol="apiv2-subpath-vol"
+podman volume create "$subpath_vol"
+podman run --rm -v "$subpath_vol":/mnt "$IMAGE" sh -c "mkdir -p /mnt/test1 /mnt/test2; touch /mnt/test1/hello1; touch /mnt/test2/hello2"
+
+t POST containers/create?name=compat_mount_subpath_test \
+  Image=$IMAGE \
+  Cmd='["ls","-1","/test1"]' \
+  HostConfig='{"Mounts":[{"Type":"volume","Source":"'$subpath_vol'","Target":"/test1","VolumeOptions":{"Subpath":"test1"}}]}' \
+  201 \
+  .Id~[0-9a-f]\\{64\\}
+cid=$(jq -r '.Id' <<<"$output")
+
+t POST containers/${cid}/start 204
+t POST containers/${cid}/wait 200
+t GET  containers/${cid}/logs?stdout=true 200
+like "$(tr -d \\0 <$WORKDIR/curl.result.out)" ".*hello1$" "compat mount subpath returns only selected subdir"
+
+t DELETE containers/${cid}?v=true 204
+podman volume rm "$subpath_vol"