expose isUpgradeable method on mutable tree and unit test

mutable_tree.go

@@ -504,14 +504,21 @@ func (tree *MutableTree) LoadVersionForOverwriting(targetVersion int64) (int64,
 	return latestVersion, nil
 }
 
+// Returns true if the tree may be auto-upgraded, false otherwise
+// An example of when an upgrade may be performed is when we are enaling fast storage for the first time or
+// need to overwrite fast nodes due to mismatch with live state.
+func (tree *MutableTree) IsUpgradeable() bool {
+	return !tree.ndb.hasUpgradedToFastStorage() || tree.ndb.shouldForceFastStorageUpgrade()
+}
+
 // enableFastStorageAndCommitIfNotEnabled if nodeDB doesn't mark fast storage as enabled, enable it, and commit the update.
 // Checks whether the fast cache on disk matches latest live state. If not, deletes all existing fast nodes and repopulates them
 // from latest tree.
 func (tree *MutableTree) enableFastStorageAndCommitIfNotEnabled() (bool, error) {
-	shouldForceUpdate := tree.ndb.shouldForceFastStorageUpdate()
+	shouldForceUpdate := tree.ndb.shouldForceFastStorageUpgrade()
 	isFastStorageEnabled := tree.ndb.hasUpgradedToFastStorage() 
 
-	if  isFastStorageEnabled && !shouldForceUpdate {
+	if !tree.IsUpgradeable() {
 		return false, nil
 	}
 

mutable_tree_test.go

@@ -678,9 +678,11 @@ func TestUpgradeStorageToFast_LatestVersion_Success(t *testing.T) {
 	randomizeTreeAndMirror(t, tree, mirror)
 
 	// Enable fast storage
+	require.True(t, tree.IsUpgradeable())
 	enabled, err := tree.enableFastStorageAndCommitIfNotEnabled()
 	require.NoError(t, err)
 	require.True(t, enabled)
+	require.False(t, tree.IsUpgradeable())
 
 	require.True(t, tree.IsFastCacheEnabled())
 }
@@ -699,10 +701,12 @@ func TestUpgradeStorageToFast_AlreadyUpgraded_Success(t *testing.T) {
 	randomizeTreeAndMirror(t, tree, mirror)
 
 	// Enable fast storage
+	require.True(t, tree.IsUpgradeable())
 	enabled, err := tree.enableFastStorageAndCommitIfNotEnabled()
 	require.NoError(t, err)
 	require.True(t, enabled)
 	require.True(t, tree.IsFastCacheEnabled())
+	require.False(t, tree.IsUpgradeable())
 
 	// Test enabling fast storage when already enabled
 	enabled, err = tree.enableFastStorageAndCommitIfNotEnabled()
@@ -799,7 +803,7 @@ func TestFastStorageReUpgradeProtection_NoForceUpgrade_Success(t *testing.T) {
 
 	// Ensure that the right branch of enableFastStorageAndCommitIfNotEnabled will be triggered
 	require.True(t, tree.IsFastCacheEnabled())
-	require.False(t, tree.ndb.shouldForceFastStorageUpdate())
+	require.False(t, tree.ndb.shouldForceFastStorageUpgrade())
 
 	enabled, err := tree.enableFastStorageAndCommitIfNotEnabled()
 	require.NoError(t, err)
@@ -886,7 +890,7 @@ func TestFastStorageReUpgradeProtection_ForceUpgradeFirstTime_NoForceSecondTime_
 
 	// Ensure that the right branch of enableFastStorageAndCommitIfNotEnabled will be triggered
 	require.True(t, tree.IsFastCacheEnabled())
-	require.True(t, tree.ndb.shouldForceFastStorageUpdate())
+	require.True(t, tree.ndb.shouldForceFastStorageUpgrade())
 
 	// Actual method under test
 	enabled, err := tree.enableFastStorageAndCommitIfNotEnabled()
@@ -904,16 +908,19 @@ func TestUpgradeStorageToFast_Integration_Upgraded_FastIterator_Success(t *testi
 	tree, mirror := setupTreeAndMirrorForUpgrade(t)
 
 	require.False(t, tree.IsFastCacheEnabled())
+	require.True(t, tree.IsUpgradeable())
 
 	// Should auto enable in save version
 	_, _, err := tree.SaveVersion()
 	require.NoError(t, err)
 
 	require.True(t, tree.IsFastCacheEnabled())
+	require.False(t, tree.IsUpgradeable())
 
 	sut, _ := NewMutableTree(tree.ndb.db, 1000)
 
 	require.False(t, sut.IsFastCacheEnabled())
+	require.False(t, sut.IsUpgradeable()) // upgraded in save version
 
 	// Load version - should auto enable fast storage
 	version, err := sut.Load()
@@ -954,16 +961,19 @@ func TestUpgradeStorageToFast_Integration_Upgraded_GetFast_Success(t *testing.T)
 	tree, mirror := setupTreeAndMirrorForUpgrade(t)
 
 	require.False(t, tree.IsFastCacheEnabled())
+	require.True(t, tree.IsUpgradeable())
 
 	// Should auto enable in save version
 	_, _, err := tree.SaveVersion()
 	require.NoError(t, err)
 
 	require.True(t, tree.IsFastCacheEnabled())
+	require.False(t, tree.IsUpgradeable())
 
 	sut, _ := NewMutableTree(tree.ndb.db, 1000)
 
 	require.False(t, sut.IsFastCacheEnabled())
+	require.False(t, sut.IsUpgradeable()) // upgraded in save version
 
 	// LazyLoadVersion - should auto enable fast storage
 	version, err := sut.LazyLoadVersion(1)

nodedb.go

@@ -253,16 +253,16 @@ func (ndb *nodeDB) getStorageVersion() string {
 	return ndb.storageVersion
 }
 
-// Returns true if the upgrade to fast storage has occurred, false otherwise.
+// Returns true if the upgrade to latest storage version has been performed, false otherwise.
 func (ndb *nodeDB) hasUpgradedToFastStorage() bool {
 	return ndb.getStorageVersion() >= fastStorageVersionValue
 }
 
 // Returns true if the upgrade to fast storage has occurred but it does not match the live state, false otherwise.
 // When the live state is not matched, we must force reupgrade.
-// We determine this by checking the version of the live state and the version of the live state wheb
-// fast storage was updated on disk the last time.
-func (ndb *nodeDB) shouldForceFastStorageUpdate() bool {
+// We determine this by checking the version of the live state and the version of the live state when
+// latest storage was updated on disk the last time.
+func (ndb *nodeDB) shouldForceFastStorageUpgrade() bool {
 	versions := strings.Split(ndb.storageVersion, fastStorageVersionDelimiter)
 
 	if len(versions) == 2 {

nodedb_test.go

@@ -185,7 +185,7 @@ func TestShouldForceFastStorageUpdate_DefaultVersion_True(t *testing.T) {
 	ndb.storageVersion = defaultStorageVersionValue
 	ndb.latestVersion = 100
 
-	require.False(t, ndb.shouldForceFastStorageUpdate())
+	require.False(t, ndb.shouldForceFastStorageUpgrade())
 }
 
 func TestShouldForceFastStorageUpdate_FastVersion_Greater_True(t *testing.T) {
@@ -194,7 +194,7 @@ func TestShouldForceFastStorageUpdate_FastVersion_Greater_True(t *testing.T) {
 	ndb.latestVersion = 100
 	ndb.storageVersion = fastStorageVersionValue + fastStorageVersionDelimiter + strconv.Itoa(int(ndb.latestVersion + 1))
 
-	require.True(t, ndb.shouldForceFastStorageUpdate())
+	require.True(t, ndb.shouldForceFastStorageUpgrade())
 }
 
 func TestShouldForceFastStorageUpdate_FastVersion_Smaller_True(t *testing.T) {
@@ -203,7 +203,7 @@ func TestShouldForceFastStorageUpdate_FastVersion_Smaller_True(t *testing.T) {
 	ndb.latestVersion = 100
 	ndb.storageVersion = fastStorageVersionValue + fastStorageVersionDelimiter + strconv.Itoa(int(ndb.latestVersion - 1))
 
-	require.True(t, ndb.shouldForceFastStorageUpdate())
+	require.True(t, ndb.shouldForceFastStorageUpgrade())
 }
 
 func TestShouldForceFastStorageUpdate_FastVersion_Match_False(t *testing.T) {
@@ -212,7 +212,7 @@ func TestShouldForceFastStorageUpdate_FastVersion_Match_False(t *testing.T) {
 	ndb.latestVersion = 100
 	ndb.storageVersion = fastStorageVersionValue + fastStorageVersionDelimiter + strconv.Itoa(int(ndb.latestVersion))
 
-	require.False(t, ndb.shouldForceFastStorageUpdate())
+	require.False(t, ndb.shouldForceFastStorageUpgrade())
 }
 
 func TestIsFastStorageEnabled_True(t *testing.T) {
@@ -230,7 +230,7 @@ func TestIsFastStorageEnabled_False(t *testing.T) {
 	ndb.latestVersion = 100
 	ndb.storageVersion = defaultStorageVersionValue
 
-	require.False(t, ndb.shouldForceFastStorageUpdate())
+	require.False(t, ndb.shouldForceFastStorageUpgrade())
 }
 
 func makeHashes(b *testing.B, seed int64) [][]byte {