diff --git a/internal/btree/btree.go b/internal/btree/btree.go
index 55d716c..ee74b62 100644
--- a/internal/btree/btree.go
+++ b/internal/btree/btree.go
@@ -138,7 +138,7 @@ func Create(name string) (*Btree, error) {
 
 // Close closes the database
 func (bt *Btree) Close() error {
-	err := bt.Close()
+	err := bt.fd.Close()
 	for i := 0; i < cacheSlots; i++ {
 		bt.cache[i] = cache{}
 	}
@@ -271,7 +271,7 @@ func (bt *Btree) remove(t *table, i int, sha1 *byte) int64 {
 	return offset
 }
 
-func (bt *Btree) insert(toff int64, sha1 *byte, data []byte, len int) int64 {
+func (bt *Btree) insert(toff int64, sha1 *byte, data []byte, size int) int64 {
 	table := bt.get(toff)
 	assert(table.size < tableSize-1)
 
@@ -296,7 +296,7 @@ func (bt *Btree) insert(toff int64, sha1 *byte, data []byte, len int) int64 {
 	lc := table.items[i].child
 	if lc != 0 {
 		/* recursion */
-		ret = bt.insert(lc, sha1, data, len)
+		ret = bt.insert(lc, sha1, data, size)
 
 		/* check if we need to split */
 		child := bt.get(lc)
@@ -314,7 +314,7 @@ func (bt *Btree) insert(toff int64, sha1 *byte, data []byte, len int) int64 {
 		// make sure data is written before a reference is added to it
 		_ = bt.fd.Sync()
 	} else {
-		off = bt.insertData(data, len)
+		off = bt.insertData(data, size)
 		ret = off
 	}
 
@@ -399,10 +399,10 @@ func (bt *Btree) delete(offset int64, hash *byte) int64 {
 	return ret
 }
 
-func (bt *Btree) insertTopLevel(toff *int64, sha1 *byte, data []byte, len int) int64 {
+func (bt *Btree) insertTopLevel(toff *int64, sha1 *byte, data []byte, size int) int64 {
 	var off, ret, rc int64
 	if *toff != 0 {
-		ret = bt.insert(*toff, sha1, data, len)
+		ret = bt.insert(*toff, sha1, data, size)
 
 		/* check if we need to split */
 		table := bt.get(*toff)
@@ -414,7 +414,7 @@ func (bt *Btree) insertTopLevel(toff *int64, sha1 *byte, data []byte, len int) i
 		rc = bt.split(table, sha1, &off)
 		bt.flush(table, *toff)
 	} else {
-		off = bt.insertData(data, len)
+		off = bt.insertData(data, size)
 		ret = off
 	}
 
@@ -471,7 +471,7 @@ func (bt *Btree) Insert(csha1 *byte, data []byte) {
 	var sha1 [sha1Size]byte
 	copysha1(&sha1[0], csha1)
 
-	bt.insertTopLevel(&bt.top, &sha1[0], data, len(data))
+	_ = bt.insertTopLevel(&bt.top, &sha1[0], data, len(data))
 	freeQueued(bt)
 	bt.flushSuper()
 }
diff --git a/internal/btree/chunk.go b/internal/btree/chunk.go
index 5d8e1bb..acae0da 100644
--- a/internal/btree/chunk.go
+++ b/internal/btree/chunk.go
@@ -26,10 +26,10 @@ func freeQueued(bt *Btree) {
 	fqueueLen = 0
 }
 
-func (bt *Btree) allocChunk(len int) int64 {
-	assert(len > 0)
+func (bt *Btree) allocChunk(size int) int64 {
+	assert(size > 0)
 
-	len = power2(len)
+	size = power2(size)
 
 	var offset int64
 	if bt.inAllocator {
@@ -38,10 +38,10 @@ func (bt *Btree) allocChunk(len int) int64 {
 		/* create fake size SHA-1 */
 		var sha1 [sha1Size]byte
 		p := unsafe.Pointer(&sha1[0])
-		*(*int32)(p) = -1                             // *(uint32_t *) sha1 = -1;
-		*(*uint32)(unsafe.Add(p, i32s)) = uint32(len) // ((__be32 *) sha1)[1] = to_be32(len);
+		*(*int32)(p) = -1                              // *(uint32_t *) sha1 = -1;
+		*(*uint32)(unsafe.Add(p, i32s)) = uint32(size) // ((__be32 *) sha1)[1] = to_be32(size);
 
-		/* find free chunk with the larger or the same len/SHA-1 */
+		/* find free chunk with the larger or the same size/SHA-1 */
 		bt.inAllocator = true
 		bt.deleteLarger = true
 		offset = bt.delete(bt.freeTop, &sha1[0])
@@ -50,20 +50,20 @@ func (bt *Btree) allocChunk(len int) int64 {
 			assert(*(*int32)(p) == -1)                   // assert(*(uint32_t *) sha1 == (uint32_t) -1)
 			flen := int(*(*uint32)(unsafe.Add(p, i32s))) // size_t free_len = from_be32(((__be32 *) sha1)[1])
 			assert(power2(flen) == flen)
-			assert(flen >= len)
+			assert(flen >= size)
 
 			/* delete buddy information */
 			resetsha1(&sha1[0])
 			*(*int64)(p) = offset
 			buddyLen := bt.delete(bt.freeTop, &sha1[0])
-			assert(buddyLen == int64(len))
+			assert(buddyLen == int64(size))
 
 			bt.freeTop = collapse(bt, bt.freeTop)
 
 			bt.inAllocator = false
 
 			/* free extra space at the end of the chunk */
-			for flen > len {
+			for flen > size {
 				flen >>= 1
 				bt.freeChunk(offset+int64(flen), flen)
 			}
@@ -75,10 +75,10 @@ func (bt *Btree) allocChunk(len int) int64 {
 		/* not found, allocate from the end of the file */
 		offset = bt.alloc
 		/* TODO: this wastes memory.. */
-		if offset&int64(len-1) != 0 {
-			offset += int64(len) - (offset & (int64(len) - 1))
+		if offset&int64(size-1) != 0 {
+			offset += int64(size) - (offset & (int64(size) - 1))
 		}
-		bt.alloc = offset + int64(len)
+		bt.alloc = offset + int64(size)
 	}
 	bt.flushSuper()
 
@@ -88,17 +88,17 @@ func (bt *Btree) allocChunk(len int) int64 {
 }
 
 /* Mark a chunk as unused in the database file */
-func (bt *Btree) freeChunk(offset int64, len int) {
-	assert(len > 0)
+func (bt *Btree) freeChunk(offset int64, size int) {
+	assert(size > 0)
 	assert(offset != 0)
-	len = power2(len)
-	assert(offset&int64(len-1) == 0)
+	size = power2(size)
+	assert(offset&int64(size-1) == 0)
 
 	if bt.inAllocator {
 		chunk := &fqueue[fqueueLen]
 		fqueueLen++
 		chunk.offset = offset
-		chunk.len = len
+		chunk.len = size
 		return
 	}
 
@@ -112,12 +112,12 @@ func (bt *Btree) freeChunk(offset int64, len int) {
 	/* add buddy information */
 	resetsha1(&sha1[0])
 	*(*int32)(p) = -1                                 // *(uint32_t *) sha1 = -1;
-	*(*uint32)(unsafe.Add(p, i32s)) = uint32(len)     // ((__be32 *) sha1)[1] = to_be32(len);
+	*(*uint32)(unsafe.Add(p, i32s)) = uint32(size)    // ((__be32 *) sha1)[1] = to_be32(size);
 	*(*uint32)(unsafe.Add(p, i32s*2)) = rand.Uint32() /* to make SHA-1 unique */
 	*(*uint32)(unsafe.Add(p, i32s*3)) = rand.Uint32()
 
 	// insert_toplevel(btree, &btree->free_top, sha1, NULL, offset);
-	bt.insertTopLevel(&bt.freeTop, &sha1[0], nil, int(offset))
+	_ = bt.insertTopLevel(&bt.freeTop, &sha1[0], nil, int(offset))
 	bt.inAllocator = false
 
 	bt.flushSuper()