From 811b7be4f171f1a59a3d3ced386cc88d596a478a Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Wed, 6 Dec 2023 12:41:44 +0300
Subject: [PATCH] Fix a memory leak in inodesByTime (evicted inodes were not
 removed from the map)

---
 internal/cluster_fs_grpc.go |  2 ++
 internal/goofys.go          |  7 +++----
 internal/handles.go         | 15 +++++++++++++++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/internal/cluster_fs_grpc.go b/internal/cluster_fs_grpc.go
index ac9efb1a..d040c1e8 100644
--- a/internal/cluster_fs_grpc.go
+++ b/internal/cluster_fs_grpc.go
@@ -464,6 +464,8 @@ func (fs *ClusterFsGrpc) ForgetInode2(ctx context.Context, req *pb.ForgetInode2R
 
 	inode.resetCache()
 	inode.fs.mu.Lock()
+	// FIXME: These lines may have a bug (check). Only expired inodes should be forgotten
+	inode.resetExpireTime()
 	delete(inode.fs.inodes, inode.Id)
 	inode.fs.mu.Unlock()
 	inode.fs.lfru.Forget(inode.Id)
diff --git a/internal/goofys.go b/internal/goofys.go
index c0f894a4..80997d36 100644
--- a/internal/goofys.go
+++ b/internal/goofys.go
@@ -834,6 +834,7 @@ func (fs *Goofys) EvictEntry(id fuseops.InodeID) bool {
 	childTmp.SetCacheState(ST_DEAD)
 	// Drop inode
 	fs.mu.Lock()
+	childTmp.resetExpireTime()
 	delete(fs.inodes, childTmp.Id)
 	fs.forgotCnt += 1
 	fs.mu.Unlock()
@@ -857,7 +858,8 @@ func (fs *Goofys) MetaEvictor() {
 		}
 		// Try to keep the number of cached inodes under control %)
 		fs.mu.RLock()
-		toEvict := (len(fs.inodes)-fs.flags.EntryLimit)*2
+		totalInodes := len(fs.inodes)
+		toEvict := (totalInodes-fs.flags.EntryLimit)*2
 		if toEvict < 0 {
 			fs.mu.RUnlock()
 			retry = false
@@ -895,10 +897,7 @@ func (fs *Goofys) MetaEvictor() {
 				seen[id] = true
 			}
 		}
-		fs.mu.RLock()
-		totalInodes := len(fs.inodes)
 		retry = len(scan) >= toEvict && totalInodes > fs.flags.EntryLimit
-		fs.mu.RUnlock()
 		atomic.AddInt64(&fs.stats.evicts, int64(evicted))
 		if len(scan) > 0 {
 			log.Debugf("metadata cache: alive %v, scanned %v, evicted %v", totalInodes, len(scan), evicted)
diff --git a/internal/handles.go b/internal/handles.go
index 7cd0c52d..58f19234 100644
--- a/internal/handles.go
+++ b/internal/handles.go
@@ -399,6 +399,7 @@ func (inode *Inode) DeRef(n int64) (stale bool) {
 	if res == 0 && inode.CacheState <= ST_DEAD {
 		inode.resetCache()
 		inode.fs.mu.Lock()
+		inode.resetExpireTime()
 		delete(inode.fs.inodes, inode.Id)
 		inode.fs.forgotCnt += 1
 		inode.fs.mu.Unlock()
@@ -446,6 +447,20 @@ func (inode *Inode) SetExpireTime(tm time.Time) {
 	inode.fs.mu.Unlock()
 }
 
+// LOCKS_REQUIRED(inode.mu)
+// LOCKS_REQUIRED(inode.fs.mu)
+func (inode *Inode) resetExpireTime() {
+	oldTime := inode.ExpireTime.Unix()
+	inode.ExpireTime = time.Time{}
+	oldMap := inode.fs.inodesByTime[oldTime]
+	if oldMap != nil {
+		delete(oldMap, inode.Id)
+		if len(oldMap) == 0 {
+			delete(inode.fs.inodesByTime, oldTime)
+		}
+	}
+}
+
 // LOCKS_EXCLUDED(inode.mu)
 // LOCKS_EXCLUDED(inode.fs.mu)
 func (inode *Inode) SetExpireLocked(tm time.Time) {