core/rawdb: fixes cornercase in tail deletion

core/rawdb/freezer_meta.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"io"
 	"os"
 
 	"github.com/ethereum/go-ethereum/rlp"
@@ -175,7 +176,7 @@ func upgradeTableIndex(index *os.File, version uint16) (*os.File, *freezerTableM
 			return nil, nil, err
 		}
 	default:
-		return nil, nil, errors.New("unknown freezer table index")
+		return nil, nil, errors.New("unknown freezer table version")
 	}
 	// Reopen the upgraded index file and load the metadata from it
 	index, err := os.Open(index.Name())
@@ -205,7 +206,7 @@ func repairTableIndex(index *os.File) (*os.File, *freezerTableMeta, error) {
 			return nil, nil, err
 		}
 		// Shift file cursor to the end for next write operation
-		_, err = index.Seek(0, 2)
+		_, err = index.Seek(0, io.SeekEnd)
 		if err != nil {
 			return nil, nil, err
 		}

core/rawdb/freezer_table.go

@@ -406,6 +406,17 @@ func (t *freezerTable) truncateHead(items uint64) error {
 	if existing <= items {
 		return nil
 	}
+	// Calculate the relative offset between the new head and tail, use
+	// it to access the corresponding index entry. If the requested target
+	// is even below the freezer tail, reject it.
+	var (
+		itemOffset = atomic.LoadUint64(&t.itemOffset)
+		itemHidden = atomic.LoadUint64(&t.itemHidden)
+		tail       = itemOffset + itemHidden
+	)
+	if items < tail {
+		return errors.New("truncation below tail")
+	}
 	// We need to truncate, save the old size for metrics tracking
 	oldSize, err := t.sizeNolock()
 	if err != nil {
@@ -418,19 +429,7 @@ func (t *freezerTable) truncateHead(items uint64) error {
 	}
 	log("Truncating freezer table", "items", existing, "limit", items)
 
-	// Calculate the relative offset between the new head and tail, use
-	// it to access the corresponding index entry. If the requested target
-	// is even below the freezer tail, reject it.
-	var (
-		itemOffset = atomic.LoadUint64(&t.itemOffset)
-		itemHidden = atomic.LoadUint64(&t.itemHidden)
-		tail       = itemOffset + itemHidden
-	)
-	if items < tail {
-		return errors.New("truncation below tail")
-	}
 	offset := items - itemOffset
-
 	if err := truncateFreezerFile(t.index, int64(offset)*indexEntrySize+metaLength); err != nil {
 		return err
 	}
@@ -498,7 +497,7 @@ func (t *freezerTable) truncateIndexFile(originDeleted, deleted, hidden uint64,
 	return nil
 }
 
-// truncateHead discards any recent data before the provided threshold number.
+// truncateTail discards any recent data before the provided threshold number.
 func (t *freezerTable) truncateTail(items uint64) error {
 	t.lock.Lock()
 	defer t.lock.Unlock()
@@ -516,17 +515,27 @@ func (t *freezerTable) truncateTail(items uint64) error {
 		return errors.New("truncation above head")
 	}
 	// Load the index of new tail item after the deletion.
-	newTail, err := t.getIndex(int64(items-deleted), 0)
+	count, err := t.indexLen()
 	if err != nil {
 		return err
 	}
+	var tailId uint32
+	if uint64(count) == items-deleted {
+		tailId = t.headId
+	} else {
+		newTail, err := t.getIndex(int64(items-deleted), 0)
+		if err != nil {
+			return err
+		}
+		tailId = newTail.filenum
+	}
 	// Freezer only supports deletion by file, just mark the entries as hidden
-	if t.tailId == newTail.filenum {
+	if t.tailId == tailId {
 		atomic.StoreUint64(&t.itemHidden, items-deleted)
 		return storeMetadata(t.index, newMetadata(t.tailId, deleted, items-deleted))
 	}
-	if t.tailId > newTail.filenum {
-		return fmt.Errorf("invalid index, tail-file %d, item-file %d", t.tailId, newTail.filenum)
+	if t.tailId > tailId {
+		return fmt.Errorf("invalid index, tail-file %d, item-file %d", t.tailId, tailId)
 	}
 	// We need to truncate, save the old size for metrics tracking
 	oldSize, err := t.sizeNolock()
@@ -540,16 +549,16 @@ func (t *freezerTable) truncateTail(items uint64) error {
 		if err != nil {
 			return err
 		}
-		if cur.filenum != newTail.filenum {
+		if cur.filenum != tailId {
 			break
 		}
 		newDeleted = current
 	}
-	if err := t.truncateIndexFile(deleted, newDeleted, items-newDeleted, newTail.filenum); err != nil {
+	if err := t.truncateIndexFile(deleted, newDeleted, items-newDeleted, tailId); err != nil {
 		return err
 	}
 	// Release any files before the current tail
-	t.tailId = newTail.filenum
+	t.tailId = tailId
 	atomic.StoreUint64(&t.itemOffset, newDeleted)
 	atomic.StoreUint64(&t.itemHidden, items-newDeleted)
 	t.releaseFilesBefore(t.tailId, true)

core/rawdb/freezer_table_test.go

@@ -760,21 +760,19 @@ func TestTruncateTail(t *testing.T) {
 	})
 
 	// truncate all, the entire freezer should be deleted
-	f.truncateTail(6)
+	f.truncateTail(7)
 	checkRetrieveError(t, f, map[uint64]error{
 		0: errOutOfBounds,
 		1: errOutOfBounds,
 		2: errOutOfBounds,
 		3: errOutOfBounds,
 		4: errOutOfBounds,
 		5: errOutOfBounds,
-	})
-	checkRetrieve(t, f, map[uint64][]byte{
-		6: getChunk(20, 0x11),
+		6: errOutOfBounds,
 	})
 }
 
-func TestTruncateHeadBelowTail(t *testing.T) {
+func TestTruncateHead(t *testing.T) {
 	t.Parallel()
 	rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
 	fname := fmt.Sprintf("truncate-head-blow-tail-%d", rand.Uint64())
@@ -822,12 +820,6 @@ func TestTruncateHeadBelowTail(t *testing.T) {
 		5: getChunk(20, 0xaa),
 		6: getChunk(20, 0x11),
 	})
-
-	f.truncateTail(5) // Lazy deleted the item-4, it's hidden
-	f.truncateHead(5) // New head is reset to item-4
-	checkRetrieveError(t, f, map[uint64]error{
-		4: errOutOfBounds, // Hidden item
-	})
 }
 
 func TestUpgradeLegacyFreezerTable(t *testing.T) {