Add a 'free' version to track deletion of tiered object content (#12470)

cmd/xl-storage-free-version.go

@@ -0,0 +1,105 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/google/uuid"
+	"github.com/minio/minio/internal/bucket/lifecycle"
+)
+
+const freeVersion = "free-version"
+
+// InitFreeVersion creates a free-version to track the tiered-content of j. If j has
+// no tiered content, it returns false.
+func (j xlMetaV2Object) InitFreeVersion(fi FileInfo) (xlMetaV2Version, bool) {
+	if status, ok := j.MetaSys[ReservedMetadataPrefixLower+TransitionStatus]; ok && bytes.Equal(status, []byte(lifecycle.TransitionComplete)) {
+		vID, err := uuid.Parse(fi.TierFreeVersionID())
+		if err != nil {
+			panic(fmt.Errorf("Invalid Tier Object delete marker versionId %s %v", fi.TierFreeVersionID(), err))
+		}
+		freeEntry := xlMetaV2Version{Type: DeleteType}
+		freeEntry.DeleteMarker = &xlMetaV2DeleteMarker{
+			VersionID: vID,
+			ModTime:   j.ModTime, // fi.ModTime may be empty
+			MetaSys:   make(map[string][]byte),
+		}
+
+		freeEntry.DeleteMarker.MetaSys[ReservedMetadataPrefixLower+freeVersion] = []byte{}
+		tierKey := ReservedMetadataPrefixLower + TransitionTier
+		tierObjKey := ReservedMetadataPrefixLower + TransitionedObjectName
+		tierObjVIDKey := ReservedMetadataPrefixLower + TransitionedVersionID
+
+		for k, v := range j.MetaSys {
+			switch k {
+			case tierKey, tierObjKey, tierObjVIDKey:
+				freeEntry.DeleteMarker.MetaSys[k] = v
+			}
+		}
+		return freeEntry, true
+	}
+	return xlMetaV2Version{}, false
+}
+
+// FreeVersion returns true if j represents a free-version, false otherwise.
+func (j xlMetaV2DeleteMarker) FreeVersion() bool {
+	_, ok := j.MetaSys[ReservedMetadataPrefixLower+freeVersion]
+	return ok
+}
+
+// FreeVersion returns true if j represents a free-version, false otherwise.
+func (j xlMetaV2Version) FreeVersion() bool {
+	switch j.Type {
+	case DeleteType:
+		return j.DeleteMarker.FreeVersion()
+	}
+	return false
+}
+
+// AddFreeVersion adds a free-version if needed for fi.VersionID version.
+// Free-version will be added if fi.VersionID has transitioned.
+func (z *xlMetaV2) AddFreeVersion(fi FileInfo) error {
+	var uv uuid.UUID
+	var err error
+	switch fi.VersionID {
+	case "", nullVersionID:
+	default:
+		uv, err = uuid.Parse(fi.VersionID)
+		if err != nil {
+			return err
+		}
+	}
+
+	for _, version := range z.Versions {
+		switch version.Type {
+		case ObjectType:
+			if version.ObjectV2.VersionID == uv {
+				// if uv has tiered content we add a
+				// free-version to track it for asynchronous
+				// deletion via scanner.
+				if freeVersion, toFree := version.ObjectV2.InitFreeVersion(fi); toFree {
+					z.Versions = append(z.Versions, freeVersion)
+				}
+				return nil
+			}
+		}
+	}
+	return nil
+}