[#1462] writecache: Fill flush marks during startup

Some of the objects are already flushed, don't do it twice.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

pkg/local_object_storage/writecache/init.go

@@ -0,0 +1,75 @@
+package writecache
+
+import (
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor"
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor/fstree"
+	meta "github.com/nspcc-dev/neofs-node/pkg/local_object_storage/metabase"
+	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
+	"go.etcd.io/bbolt"
+)
+
+func (c *cache) initFlushMarks() {
+	c.log.Info("filling flush marks for objects in FSTree")
+
+	var prm fstree.IterationPrm
+	prm.WithLazyHandler(func(addr oid.Address, _ func() ([]byte, error)) error {
+		if c.isFlushed(addr) {
+			c.store.flushed.Add(addr.EncodeToString(), true)
+		}
+		return nil
+	})
+	_ = c.fsTree.Iterate(prm)
+
+	c.log.Info("filling flush marks for objects in database")
+
+	var m []string
+	var lastKey []byte
+	var batchSize = flushBatchSize
+	for {
+		m = m[:0]
+
+		// We put objects in batches of fixed size to not interfere with main put cycle a lot.
+		_ = c.db.View(func(tx *bbolt.Tx) error {
+			b := tx.Bucket(defaultBucket)
+			cs := b.Cursor()
+			for k, _ := cs.Seek(lastKey); k != nil && len(m) < batchSize; k, _ = cs.Next() {
+				m = append(m, string(k))
+			}
+			return nil
+		})
+
+		var addr oid.Address
+		for i := range m {
+			if err := addr.DecodeString(m[i]); err != nil {
+				continue
+			}
+
+			if c.isFlushed(addr) {
+				c.store.flushed.Add(addr.EncodeToString(), true)
+			}
+		}
+
+		if len(m) == 0 {
+			break
+		}
+		lastKey = append([]byte(m[len(m)-1]), 0)
+	}
+
+	c.log.Info("finished updating flush marks")
+}
+
+func (c *cache) isFlushed(addr oid.Address) bool {
+	var existsPrm meta.ExistsPrm
+	existsPrm.WithAddress(addr)
+
+	mRes, err := c.metabase.Exists(existsPrm)
+	if err != nil || !mRes.Exists() {
+		return false
+	}
+
+	var prm blobstor.ExistsPrm
+	prm.SetAddress(addr)
+
+	res, err := c.blobstor.Exists(prm)
+	return err == nil && res.Exists()
+}

pkg/local_object_storage/writecache/writecache.go

@@ -133,6 +133,8 @@ func (c *cache) Open() error {
 
 // Init runs necessary services.
 func (c *cache) Init() error {
+	c.initFlushMarks()
+
 	go c.persistLoop()
 	go c.flushLoop()
 	return nil