diff --git a/pkg/local_object_storage/blobstor/fstree/counter.go b/pkg/local_object_storage/blobstor/fstree/counter.go
index 718104e2e..b5dbc9e40 100644
--- a/pkg/local_object_storage/blobstor/fstree/counter.go
+++ b/pkg/local_object_storage/blobstor/fstree/counter.go
@@ -1,22 +1,21 @@
 package fstree
 
 import (
-	"math"
-	"sync/atomic"
+	"sync"
 )
 
 // FileCounter used to count files in FSTree. The implementation must be thread-safe.
 type FileCounter interface {
-	Set(v uint64)
-	Inc()
-	Dec()
+	Set(count, size uint64)
+	Inc(size uint64)
+	Dec(size uint64)
 }
 
 type noopCounter struct{}
 
-func (c *noopCounter) Set(uint64) {}
-func (c *noopCounter) Inc()       {}
-func (c *noopCounter) Dec()       {}
+func (c *noopCounter) Set(uint64, uint64) {}
+func (c *noopCounter) Inc(uint64)         {}
+func (c *noopCounter) Dec(uint64)         {}
 
 func counterEnabled(c FileCounter) bool {
 	_, noop := c.(*noopCounter)
@@ -24,14 +23,50 @@ func counterEnabled(c FileCounter) bool {
 }
 
 type SimpleCounter struct {
-	v atomic.Uint64
+	mtx   sync.RWMutex
+	count uint64
+	size  uint64
 }
 
 func NewSimpleCounter() *SimpleCounter {
 	return &SimpleCounter{}
 }
 
-func (c *SimpleCounter) Set(v uint64)  { c.v.Store(v) }
-func (c *SimpleCounter) Inc()          { c.v.Add(1) }
-func (c *SimpleCounter) Dec()          { c.v.Add(math.MaxUint64) }
-func (c *SimpleCounter) Value() uint64 { return c.v.Load() }
+func (c *SimpleCounter) Set(count, size uint64) {
+	c.mtx.Lock()
+	defer c.mtx.Unlock()
+
+	c.count = count
+	c.size = size
+}
+
+func (c *SimpleCounter) Inc(size uint64) {
+	c.mtx.Lock()
+	defer c.mtx.Unlock()
+
+	c.count++
+	c.size += size
+}
+
+func (c *SimpleCounter) Dec(size uint64) {
+	c.mtx.Lock()
+	defer c.mtx.Unlock()
+
+	if c.count > 0 {
+		c.count--
+	} else {
+		panic("fstree.SimpleCounter: invalid count")
+	}
+	if c.size >= size {
+		c.size -= size
+	} else {
+		panic("fstree.SimpleCounter: invalid size")
+	}
+}
+
+func (c *SimpleCounter) CountSize() (uint64, uint64) {
+	c.mtx.RLock()
+	defer c.mtx.RUnlock()
+
+	return c.count, c.size
+}
diff --git a/pkg/local_object_storage/blobstor/fstree/fstree.go b/pkg/local_object_storage/blobstor/fstree/fstree.go
index 02580dbfa..bf6ba51e5 100644
--- a/pkg/local_object_storage/blobstor/fstree/fstree.go
+++ b/pkg/local_object_storage/blobstor/fstree/fstree.go
@@ -435,32 +435,38 @@ func (t *FSTree) initFileCounter() error {
 		return nil
 	}
 
-	counter, err := t.countFiles()
+	count, size, err := t.countFiles()
 	if err != nil {
 		return err
 	}
-	t.fileCounter.Set(counter)
+	t.fileCounter.Set(count, size)
 	return nil
 }
 
-func (t *FSTree) countFiles() (uint64, error) {
-	var counter uint64
+func (t *FSTree) countFiles() (uint64, uint64, error) {
+	var count, size uint64
 	// it is simpler to just consider every file
 	// that is not directory as an object
 	err := filepath.WalkDir(t.RootPath,
 		func(_ string, d fs.DirEntry, _ error) error {
-			if !d.IsDir() {
-				counter++
+			if d.IsDir() {
+				return nil
 			}
+			count++
+			info, err := d.Info()
+			if err != nil {
+				return err
+			}
+			size += uint64(info.Size())
 
 			return nil
 		},
 	)
 	if err != nil {
-		return 0, fmt.Errorf("could not walk through %s directory: %w", t.RootPath, err)
+		return 0, 0, fmt.Errorf("could not walk through %s directory: %w", t.RootPath, err)
 	}
 
-	return counter, nil
+	return count, size, nil
 }
 
 func (t *FSTree) ObjectsCount(ctx context.Context) (uint64, error) {
diff --git a/pkg/local_object_storage/blobstor/fstree/fstree_test.go b/pkg/local_object_storage/blobstor/fstree/fstree_test.go
index 5786dfd3b..f39c7296e 100644
--- a/pkg/local_object_storage/blobstor/fstree/fstree_test.go
+++ b/pkg/local_object_storage/blobstor/fstree/fstree_test.go
@@ -47,8 +47,9 @@ func TestObjectCounter(t *testing.T) {
 	require.NoError(t, fst.Open(mode.ComponentReadWrite))
 	require.NoError(t, fst.Init())
 
-	counterValue := counter.Value()
-	require.Equal(t, uint64(0), counterValue)
+	count, size := counter.CountSize()
+	require.Equal(t, uint64(0), count)
+	require.Equal(t, uint64(0), size)
 
 	defer func() {
 		require.NoError(t, fst.Close())
@@ -64,9 +65,6 @@ func TestObjectCounter(t *testing.T) {
 	putPrm.Address = addr
 	putPrm.RawData, _ = obj.Marshal()
 
-	var getPrm common.GetPrm
-	getPrm.Address = putPrm.Address
-
 	var delPrm common.DeletePrm
 	delPrm.Address = addr
 
@@ -95,8 +93,9 @@ func TestObjectCounter(t *testing.T) {
 
 	require.NoError(t, eg.Wait())
 
-	counterValue = counter.Value()
-	realCount, err := fst.countFiles()
+	count, size = counter.CountSize()
+	realCount, realSize, err := fst.countFiles()
 	require.NoError(t, err)
-	require.Equal(t, realCount, counterValue)
+	require.Equal(t, realCount, count, "real %d, actual %d", realCount, count)
+	require.Equal(t, realSize, size, "real %d, actual %d", realSize, size)
 }
diff --git a/pkg/local_object_storage/blobstor/fstree/fstree_write_generic.go b/pkg/local_object_storage/blobstor/fstree/fstree_write_generic.go
index 8b2622885..801fc4a22 100644
--- a/pkg/local_object_storage/blobstor/fstree/fstree_write_generic.go
+++ b/pkg/local_object_storage/blobstor/fstree/fstree_write_generic.go
@@ -78,14 +78,14 @@ func (w *genericWriter) writeAndRename(tmpPath, p string, data []byte) error {
 	}
 
 	if w.fileCounterEnabled {
-		w.fileCounter.Inc()
+		w.fileCounter.Inc(uint64(len(data)))
 		var targetFileExists bool
 		if _, e := os.Stat(p); e == nil {
 			targetFileExists = true
 		}
 		err = os.Rename(tmpPath, p)
 		if err == nil && targetFileExists {
-			w.fileCounter.Dec()
+			w.fileCounter.Dec(uint64(len(data)))
 		}
 	} else {
 		err = os.Rename(tmpPath, p)
@@ -110,12 +110,7 @@ func (w *genericWriter) writeFile(p string, data []byte) error {
 func (w *genericWriter) removeFile(p string) error {
 	var err error
 	if w.fileCounterEnabled {
-		w.fileGuard.Lock(p)
-		err = os.Remove(p)
-		w.fileGuard.Unlock(p)
-		if err == nil {
-			w.fileCounter.Dec()
-		}
+		err = w.removeWithCounter(p)
 	} else {
 		err = os.Remove(p)
 	}
@@ -125,3 +120,19 @@ func (w *genericWriter) removeFile(p string) error {
 	}
 	return err
 }
+
+func (w *genericWriter) removeWithCounter(p string) error {
+	w.fileGuard.Lock(p)
+	defer w.fileGuard.Unlock(p)
+
+	stat, err := os.Stat(p)
+	if err != nil {
+		return err
+	}
+
+	if err := os.Remove(p); err != nil {
+		return err
+	}
+	w.fileCounter.Dec(uint64(stat.Size()))
+	return nil
+}
diff --git a/pkg/local_object_storage/blobstor/fstree/fstree_write_linux.go b/pkg/local_object_storage/blobstor/fstree/fstree_write_linux.go
index efc5a3d3d..3127579ac 100644
--- a/pkg/local_object_storage/blobstor/fstree/fstree_write_linux.go
+++ b/pkg/local_object_storage/blobstor/fstree/fstree_write_linux.go
@@ -9,6 +9,7 @@ import (
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
+	utilSync "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/sync"
 	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
 	"golang.org/x/sys/unix"
 )
@@ -18,7 +19,9 @@ type linuxWriter struct {
 	perm  uint32
 	flags int
 
-	counter FileCounter
+	fileGuard          keyLock
+	fileCounter        FileCounter
+	fileCounterEnabled bool
 }
 
 func newSpecificWriteData(c FileCounter, root string, perm fs.FileMode, noSync bool) writer {
@@ -33,11 +36,18 @@ func newSpecificWriteData(c FileCounter, root string, perm fs.FileMode, noSync b
 		return nil
 	}
 	_ = unix.Close(fd) // Don't care about error.
+	var fileGuard keyLock = &noopKeyLock{}
+	fileCounterEnabled := counterEnabled(c)
+	if fileCounterEnabled {
+		fileGuard = utilSync.NewKeyLocker[string]()
+	}
 	w := &linuxWriter{
-		root:    root,
-		perm:    uint32(perm),
-		flags:   flags,
-		counter: c,
+		root:               root,
+		perm:               uint32(perm),
+		flags:              flags,
+		fileGuard:          fileGuard,
+		fileCounter:        c,
+		fileCounterEnabled: fileCounterEnabled,
 	}
 	return w
 }
@@ -51,6 +61,10 @@ func (w *linuxWriter) writeData(p string, data []byte) error {
 }
 
 func (w *linuxWriter) writeFile(p string, data []byte) error {
+	if w.fileCounterEnabled {
+		w.fileGuard.Lock(p)
+		defer w.fileGuard.Unlock(p)
+	}
 	fd, err := unix.Open(w.root, w.flags, w.perm)
 	if err != nil {
 		return err
@@ -61,7 +75,7 @@ func (w *linuxWriter) writeFile(p string, data []byte) error {
 		if n == len(data) {
 			err = unix.Linkat(unix.AT_FDCWD, tmpPath, unix.AT_FDCWD, p, unix.AT_SYMLINK_FOLLOW)
 			if err == nil {
-				w.counter.Inc()
+				w.fileCounter.Inc(uint64(len(data)))
 			}
 			if errors.Is(err, unix.EEXIST) {
 				err = nil
@@ -78,12 +92,24 @@ func (w *linuxWriter) writeFile(p string, data []byte) error {
 }
 
 func (w *linuxWriter) removeFile(p string) error {
-	err := unix.Unlink(p)
+	if w.fileCounterEnabled {
+		w.fileGuard.Lock(p)
+		defer w.fileGuard.Unlock(p)
+	}
+	var stat unix.Stat_t
+	err := unix.Stat(p, &stat)
+	if err != nil {
+		if err == unix.ENOENT {
+			return logicerr.Wrap(new(apistatus.ObjectNotFound))
+		}
+		return err
+	}
+	err = unix.Unlink(p)
 	if err != nil && err == unix.ENOENT {
 		return logicerr.Wrap(new(apistatus.ObjectNotFound))
 	}
 	if err == nil {
-		w.counter.Dec()
+		w.fileCounter.Dec(uint64(stat.Size))
 	}
 	return err
 }
diff --git a/pkg/local_object_storage/writecache/cache.go b/pkg/local_object_storage/writecache/cache.go
index ff38de407..f2280f2f4 100644
--- a/pkg/local_object_storage/writecache/cache.go
+++ b/pkg/local_object_storage/writecache/cache.go
@@ -29,6 +29,8 @@ type cache struct {
 	wg sync.WaitGroup
 	// fsTree contains big files stored directly on file-system.
 	fsTree *fstree.FSTree
+	// counter contains atomic counters for the number of objects stored in cache.
+	counter *fstree.SimpleCounter
 }
 
 // wcStorageType is used for write-cache operations logging.
@@ -56,6 +58,7 @@ func New(opts ...Option) Cache {
 	c := &cache{
 		flushCh: make(chan objectInfo),
 		mode:    mode.Disabled,
+		counter: fstree.NewSimpleCounter(),
 
 		options: options{
 			log:             &logger.Logger{Logger: zap.NewNop()},
diff --git a/pkg/local_object_storage/writecache/options.go b/pkg/local_object_storage/writecache/options.go
index 7845c5da9..0643faac0 100644
--- a/pkg/local_object_storage/writecache/options.go
+++ b/pkg/local_object_storage/writecache/options.go
@@ -30,8 +30,6 @@ type options struct {
 	// maxCacheCount is the maximum total count of all object saved in cache.
 	// 0 (no limit) by default.
 	maxCacheCount uint64
-	// objCounters contains atomic counters for the number of objects stored in cache.
-	objCounters counters
 	// maxBatchSize is the maximum batch size for the small object database.
 	maxBatchSize int
 	// maxBatchDelay is the maximum batch wait time for the small object database.
diff --git a/pkg/local_object_storage/writecache/state.go b/pkg/local_object_storage/writecache/state.go
index e4e22f404..748c78bcb 100644
--- a/pkg/local_object_storage/writecache/state.go
+++ b/pkg/local_object_storage/writecache/state.go
@@ -1,18 +1,10 @@
 package writecache
 
-import (
-	"math"
-	"sync/atomic"
-
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/fstree"
-)
-
 func (c *cache) estimateCacheSize() (uint64, uint64) {
-	fsCount := c.objCounters.FS()
-	fsSize := fsCount * c.maxObjectSize
-	c.metrics.SetEstimateSize(0, fsSize)
-	c.metrics.SetActualCounters(0, fsCount)
-	return fsCount, fsSize
+	count, size := c.counter.CountSize()
+	c.metrics.SetEstimateSize(0, size)
+	c.metrics.SetActualCounters(0, count)
+	return count, size
 }
 
 func (c *cache) hasEnoughSpaceFS() bool {
@@ -27,31 +19,6 @@ func (c *cache) hasEnoughSpace(objectSize uint64) bool {
 	return c.maxCacheSize >= size+objectSize
 }
 
-var _ fstree.FileCounter = &counters{}
-
-type counters struct {
-	cFS atomic.Uint64
-}
-
-func (x *counters) FS() uint64 {
-	return x.cFS.Load()
-}
-
-// Set implements fstree.ObjectCounter.
-func (x *counters) Set(v uint64) {
-	x.cFS.Store(v)
-}
-
-// Inc implements fstree.ObjectCounter.
-func (x *counters) Inc() {
-	x.cFS.Add(1)
-}
-
-// Dec implements fstree.ObjectCounter.
-func (x *counters) Dec() {
-	x.cFS.Add(math.MaxUint64)
-}
-
 func (c *cache) initCounters() error {
 	c.estimateCacheSize()
 	return nil
diff --git a/pkg/local_object_storage/writecache/storage.go b/pkg/local_object_storage/writecache/storage.go
index 309bd2a66..e708a529e 100644
--- a/pkg/local_object_storage/writecache/storage.go
+++ b/pkg/local_object_storage/writecache/storage.go
@@ -30,7 +30,7 @@ func (c *cache) openStore(mod mode.ComponentMode) error {
 		fstree.WithDepth(1),
 		fstree.WithDirNameLen(1),
 		fstree.WithNoSync(c.noSync),
-		fstree.WithFileCounter(&c.objCounters),
+		fstree.WithFileCounter(c.counter),
 	)
 	if err := c.fsTree.Open(mod); err != nil {
 		return fmt.Errorf("could not open FSTree: %w", err)