add reification limit

blockstore/splitstore/splitstore_reify.go

@@ -1,6 +1,7 @@
 package splitstore
 
 import (
+	"errors"
 	"runtime"
 	"sync/atomic"
 
@@ -10,13 +11,12 @@ import (
 	cid "github.com/ipfs/go-cid"
 )
 
-var EnableReification = false
+var (
+	errReifyLimit = errors.New("reification limit reached")
+	ReifyLimit    = 16384
+)
 
 func (s *SplitStore) reifyColdObject(c cid.Cid) {
-	if !EnableReification {
-		return
-	}
-
 	if !s.isWarm() {
 		return
 	}
@@ -104,12 +104,18 @@ func (s *SplitStore) doReify(c cid.Cid) {
 	s.txnLk.RLock()
 	defer s.txnLk.RUnlock()
 
+	count := 0
 	err := s.walkObjectIncomplete(c, newTmpVisitor(),
 		func(c cid.Cid) error {
 			if isUnitaryObject(c) {
 				return errStopWalk
 			}
 
+			count++
+			if count > ReifyLimit {
+				return errReifyLimit
+			}
+
 			s.reifyMx.Lock()
 			_, inProgress := s.reifyInProgress[c]
 			if !inProgress {
@@ -150,6 +156,11 @@ func (s *SplitStore) doReify(c cid.Cid) {
 		})
 
 	if err != nil {
+		if xerrors.Is(err, errReifyLimit) {
+			log.Debug("reification aborted; reify limit reached")
+			return
+		}
+
 		log.Warnf("error walking cold object for reification (cid: %s): %s", c, err)
 		return
 	}