[#536] blobovnicza: Drop cache

Each blobovnicza instance is opened
while is in use.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/blobstor/blobovniczatree/active.go

@@ -0,0 +1,213 @@
+package blobovniczatree
+
+import (
+	"path/filepath"
+	"sync"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobovnicza"
+	utilSync "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/sync"
+)
+
+type activeDB struct {
+	blz  *blobovnicza.Blobovnicza
+	shDB *sharedDB
+}
+
+func (db *activeDB) Blobovnicza() *blobovnicza.Blobovnicza {
+	return db.blz
+}
+
+func (db *activeDB) Close() {
+	db.shDB.Close()
+}
+
+func (db *activeDB) Path() string {
+	return db.shDB.Path()
+}
+
+// activeDBManager manages active blobovnicza instances (that is, those that are being used for Put).
+//
+// Uses dbManager for opening/closing sharedDB instances.
+// Stores a reference to an open active sharedDB, so dbManager does not close it.
+// When changing the active sharedDB, releases the reference to the previous active sharedDB.
+type activeDBManager struct {
+	levelToActiveDBGuard *sync.RWMutex
+	levelToActiveDB      map[string]*sharedDB
+	levelLock            *utilSync.KeyLocker[string]
+	closed               bool
+
+	dbManager *dbManager
+	leafWidth uint64
+}
+
+func newActiveDBManager(dbManager *dbManager, leafWidth uint64) *activeDBManager {
+	return &activeDBManager{
+		levelToActiveDBGuard: &sync.RWMutex{},
+		levelToActiveDB:      make(map[string]*sharedDB),
+		levelLock:            utilSync.NewKeyLocker[string](),
+
+		dbManager: dbManager,
+		leafWidth: leafWidth,
+	}
+}
+
+// GetOpenedActiveDBForLevel returns active DB for level.
+// DB must be closed after use.
+func (m *activeDBManager) GetOpenedActiveDBForLevel(lvlPath string) (*activeDB, error) {
+	activeDB, err := m.getCurrentActiveIfOk(lvlPath)
+	if err != nil {
+		return nil, err
+	}
+	if activeDB != nil {
+		return activeDB, nil
+	}
+
+	return m.updateAndGetActive(lvlPath)
+}
+
+func (m *activeDBManager) Open() {
+	m.levelToActiveDBGuard.Lock()
+	defer m.levelToActiveDBGuard.Unlock()
+
+	m.closed = false
+}
+
+func (m *activeDBManager) Close() {
+	m.levelToActiveDBGuard.Lock()
+	defer m.levelToActiveDBGuard.Unlock()
+
+	for _, db := range m.levelToActiveDB {
+		db.Close()
+	}
+	m.levelToActiveDB = make(map[string]*sharedDB)
+	m.closed = true
+}
+
+func (m *activeDBManager) getCurrentActiveIfOk(lvlPath string) (*activeDB, error) {
+	m.levelToActiveDBGuard.RLock()
+	defer m.levelToActiveDBGuard.RUnlock()
+
+	if m.closed {
+		return nil, errClosed
+	}
+
+	db, ok := m.levelToActiveDB[lvlPath]
+	if !ok {
+		return nil, nil
+	}
+
+	blz, err := db.Open() //open db for usage, will be closed on activeDB.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	if blz.IsFull() {
+		db.Close()
+		return nil, nil
+	}
+
+	return &activeDB{
+		blz:  blz,
+		shDB: db,
+	}, nil
+}
+
+func (m *activeDBManager) updateAndGetActive(lvlPath string) (*activeDB, error) {
+	m.levelLock.Lock(lvlPath)
+	defer m.levelLock.Unlock(lvlPath)
+
+	current, err := m.getCurrentActiveIfOk(lvlPath)
+	if err != nil {
+		return nil, err
+	}
+	if current != nil {
+		return current, nil
+	}
+
+	nextShDB, err := m.getNextSharedDB(lvlPath)
+	if err != nil {
+		return nil, err
+	}
+
+	if nextShDB == nil {
+		return nil, nil
+	}
+
+	blz, err := nextShDB.Open() // open db for client, client must call Close() after usage
+	if err != nil {
+		return nil, err
+	}
+	return &activeDB{
+		blz:  blz,
+		shDB: nextShDB,
+	}, nil
+}
+
+func (m *activeDBManager) getNextSharedDB(lvlPath string) (*sharedDB, error) {
+	var idx uint64
+	var iterCount uint64
+	hasActive, currentIdx := m.hasActiveDB(lvlPath)
+	if hasActive {
+		idx = (currentIdx + 1) % m.leafWidth
+	}
+
+	var next *sharedDB
+
+	for iterCount < m.leafWidth {
+		path := filepath.Join(lvlPath, u64ToHexString(idx))
+		shDB := m.dbManager.GetByPath(path)
+		db, err := shDB.Open() //open db to hold active DB open, will be closed if db is full, after m.replace or by activeDBManager.Close()
+		if err != nil {
+			return nil, err
+		}
+		if db.IsFull() {
+			shDB.Close()
+		} else {
+			next = shDB
+			break
+		}
+		idx = (idx + 1) % m.leafWidth
+		iterCount++
+	}
+
+	previous, updated := m.replace(lvlPath, next)
+	if !updated && next != nil {
+		next.Close() // manager is closed, so don't hold active DB open
+	}
+	if updated && previous != nil {
+		previous.Close()
+	}
+	return next, nil
+}
+
+func (m *activeDBManager) hasActiveDB(lvlPath string) (bool, uint64) {
+	m.levelToActiveDBGuard.RLock()
+	defer m.levelToActiveDBGuard.RUnlock()
+
+	if m.closed {
+		return false, 0
+	}
+
+	db, ok := m.levelToActiveDB[lvlPath]
+	if !ok {
+		return false, 0
+	}
+	return true, u64FromHexString(filepath.Base(db.Path()))
+}
+
+func (m *activeDBManager) replace(lvlPath string, shDB *sharedDB) (*sharedDB, bool) {
+	m.levelToActiveDBGuard.Lock()
+	defer m.levelToActiveDBGuard.Unlock()
+
+	if m.closed {
+		return nil, false
+	}
+
+	previous := m.levelToActiveDB[lvlPath]
+	if shDB == nil {
+		delete(m.levelToActiveDB, lvlPath)
+	} else {
+		m.levelToActiveDB[lvlPath] = shDB
+	}
+	return previous, true
+}