btrfsitem: Have all Item implementations be pointers to structs

18 files changed, 166 insertions, 160 deletions

diff --git a/lib/btrfs/Makefile b/lib/btrfs/Makefile
index cbcaf9e..00c22e7 100644
--- a/lib/btrfs/Makefile
+++ b/lib/btrfs/Makefile
@@ -35,7 +35,7 @@ btrfsitem/items_gen.go: btrfsitem/items.txt $(MAKEFILE_LIST)
 	  echo 'var untypedObjID2gotype = map[btrfsprim.ObjID]reflect.Type{'; \
 	  sed -En 's|UNTYPED=0:(.*) (.*)|btrfsprim.\1: reflect.TypeOf(\2{}),|p' $<; \
 	  echo '}'; \
-	  sed -En 's,(.*)=(.*) (.+),\3,p' $< | LC_COLLATE=C sort -u | sed 's,.*,func (&) isItem() {},'; \
+	  sed -En 's,(.*)=(.*) (.+),\3,p' $< | LC_COLLATE=C sort -u | sed 's,.*,func (*&) isItem() {},'; \
 	} | gofmt >$@
 files += btrfsitem/items_gen.go
 
diff --git a/lib/btrfs/btrfsitem/item_extent.go b/lib/btrfs/btrfsitem/item_extent.go
index 66aae1d..72371a9 100644
--- a/lib/btrfs/btrfsitem/item_extent.go
+++ b/lib/btrfs/btrfsitem/item_extent.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -114,8 +114,8 @@ func (o *ExtentInlineRef) UnmarshalBinary(dat []byte) (int, error) {
 			return n, err
 		}
 	case EXTENT_DATA_REF_KEY:
-		var dref ExtentDataRef
-		_n, err := binstruct.Unmarshal(dat[n:], &dref)
+		dref := new(ExtentDataRef)
+		_n, err := binstruct.Unmarshal(dat[n:], dref)
 		n += _n
 		o.Body = dref
 		if err != nil {
@@ -127,8 +127,8 @@ func (o *ExtentInlineRef) UnmarshalBinary(dat []byte) (int, error) {
 		if err != nil {
 			return n, err
 		}
-		var sref SharedDataRef
-		_n, err = binstruct.Unmarshal(dat[n:], &sref)
+		sref := new(SharedDataRef)
+		_n, err = binstruct.Unmarshal(dat[n:], sref)
 		n += _n
 		o.Body = sref
 		if err != nil {
diff --git a/lib/btrfs/btrfsitem/item_freespacebitmap.go b/lib/btrfs/btrfsitem/item_freespacebitmap.go
index ad46204..742d126 100644
--- a/lib/btrfs/btrfsitem/item_freespacebitmap.go
+++ b/lib/btrfs/btrfsitem/item_freespacebitmap.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -6,13 +6,15 @@ package btrfsitem
 
 // key.objectid = object ID of the FreeSpaceInfo (logical_addr)
 // key.offset = offset of the FreeSpaceInfo (size)
-type FreeSpaceBitmap []byte // FREE_SPACE_BITMAP=200
+type FreeSpaceBitmap struct { // FREE_SPACE_BITMAP=200
+	Bitmap []byte
+}
 
 func (o *FreeSpaceBitmap) UnmarshalBinary(dat []byte) (int, error) {
-	*o = dat
+	o.Bitmap = dat
 	return len(dat), nil
 }
 
 func (o FreeSpaceBitmap) MarshalBinary() ([]byte, error) {
-	return []byte(o), nil
+	return o.Bitmap, nil
 }
diff --git a/lib/btrfs/btrfsitem/item_inoderef.go b/lib/btrfs/btrfsitem/item_inoderef.go
index 083f19e..c90fe44 100644
--- a/lib/btrfs/btrfsitem/item_inoderef.go
+++ b/lib/btrfs/btrfsitem/item_inoderef.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -16,10 +16,12 @@ import (
 //
 // Might have multiple entries if the same file has multiple hardlinks
 // in the same directory.
-type InodeRefs []InodeRef // INODE_REF=12
+type InodeRefs struct { // INODE_REF=12
+	Refs []InodeRef
+}
 
 func (o *InodeRefs) UnmarshalBinary(dat []byte) (int, error) {
-	*o = nil
+	o.Refs = nil
 	n := 0
 	for n < len(dat) {
 		var ref InodeRef
@@ -28,14 +30,14 @@ func (o *InodeRefs) UnmarshalBinary(dat []byte) (int, error) {
 		if err != nil {
 			return n, err
 		}
-		*o = append(*o, ref)
+		o.Refs = append(o.Refs, ref)
 	}
 	return n, nil
 }
 
 func (o InodeRefs) MarshalBinary() ([]byte, error) {
 	var dat []byte
-	for _, ref := range o {
+	for _, ref := range o.Refs {
 		_dat, err := binstruct.Marshal(ref)
 		dat = append(dat, _dat...)
 		if err != nil {
diff --git a/lib/btrfs/btrfsitem/items.go b/lib/btrfs/btrfsitem/items.go
index 67f96fa..9964e2d 100644
--- a/lib/btrfs/btrfsitem/items.go
+++ b/lib/btrfs/btrfsitem/items.go
@@ -25,7 +25,7 @@ type Error struct {
 	Err error
 }
 
-func (Error) isItem() {}
+func (*Error) isItem() {}
 
 func (o Error) MarshalBinary() ([]byte, error) {
 	return o.Dat, nil
@@ -43,7 +43,7 @@ func UnmarshalItem(key btrfsprim.Key, csumType btrfssum.CSumType, dat []byte) It
 		var ok bool
 		gotyp, ok = untypedObjID2gotype[key.ObjectID]
 		if !ok {
-			return Error{
+			return &Error{
 				Dat: dat,
 				Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v, ObjectID:%v}, dat): unknown object ID for untyped item",
 					key.ItemType, key.ObjectID),
@@ -53,31 +53,31 @@ func UnmarshalItem(key btrfsprim.Key, csumType btrfssum.CSumType, dat []byte) It
 		var ok bool
 		gotyp, ok = keytype2gotype[key.ItemType]
 		if !ok {
-			return Error{
+			return &Error{
 				Dat: dat,
 				Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v}, dat): unknown item type", key.ItemType),
 			}
 		}
 	}
-	retPtr := reflect.New(gotyp)
-	if csums, ok := retPtr.Interface().(*ExtentCSum); ok {
+	ptr := reflect.New(gotyp)
+	if csums, ok := ptr.Interface().(*ExtentCSum); ok {
 		csums.ChecksumSize = csumType.Size()
 		csums.Addr = btrfsvol.LogicalAddr(key.Offset)
 	}
-	n, err := binstruct.Unmarshal(dat, retPtr.Interface())
+	n, err := binstruct.Unmarshal(dat, ptr.Interface())
 	if err != nil {
-		return Error{
+		return &Error{
 			Dat: dat,
 			Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v}, dat): %w", key.ItemType, err),
 		}
 	}
 	if n < len(dat) {
-		return Error{
+		return &Error{
 			Dat: dat,
 			Err: fmt.Errorf("btrfsitem.UnmarshalItem({ItemType:%v}, dat): left over data: got %v bytes but only consumed %v",
 				key.ItemType, len(dat), n),
 		}
 	}
 	//nolint:forcetypeassert // items_gen.go has all types in keytype2gotype implement the Item interface.
-	return retPtr.Elem().Interface().(Item)
+	return ptr.Interface().(Item)
 }
diff --git a/lib/btrfs/btrfsitem/items_gen.go b/lib/btrfs/btrfsitem/items_gen.go
index 9daef81..21c6795 100644
--- a/lib/btrfs/btrfsitem/items_gen.go
+++ b/lib/btrfs/btrfsitem/items_gen.go
@@ -80,27 +80,27 @@ var untypedObjID2gotype = map[btrfsprim.ObjID]reflect.Type{
 	btrfsprim.FREE_SPACE_OBJECTID: reflect.TypeOf(FreeSpaceHeader{}),
 }
 
-func (BlockGroup) isItem()      {}
-func (Chunk) isItem()           {}
-func (Dev) isItem()             {}
-func (DevExtent) isItem()       {}
-func (DevStats) isItem()        {}
-func (DirEntry) isItem()        {}
-func (Empty) isItem()           {}
-func (Extent) isItem()          {}
-func (ExtentCSum) isItem()      {}
-func (ExtentDataRef) isItem()   {}
-func (FileExtent) isItem()      {}
-func (FreeSpaceBitmap) isItem() {}
-func (FreeSpaceHeader) isItem() {}
-func (FreeSpaceInfo) isItem()   {}
-func (Inode) isItem()           {}
-func (InodeRefs) isItem()       {}
-func (Metadata) isItem()        {}
-func (QGroupInfo) isItem()      {}
-func (QGroupLimit) isItem()     {}
-func (QGroupStatus) isItem()    {}
-func (Root) isItem()            {}
-func (RootRef) isItem()         {}
-func (SharedDataRef) isItem()   {}
-func (UUIDMap) isItem()         {}
+func (*BlockGroup) isItem()      {}
+func (*Chunk) isItem()           {}
+func (*Dev) isItem()             {}
+func (*DevExtent) isItem()       {}
+func (*DevStats) isItem()        {}
+func (*DirEntry) isItem()        {}
+func (*Empty) isItem()           {}
+func (*Extent) isItem()          {}
+func (*ExtentCSum) isItem()      {}
+func (*ExtentDataRef) isItem()   {}
+func (*FileExtent) isItem()      {}
+func (*FreeSpaceBitmap) isItem() {}
+func (*FreeSpaceHeader) isItem() {}
+func (*FreeSpaceInfo) isItem()   {}
+func (*Inode) isItem()           {}
+func (*InodeRefs) isItem()       {}
+func (*Metadata) isItem()        {}
+func (*QGroupInfo) isItem()      {}
+func (*QGroupLimit) isItem()     {}
+func (*QGroupStatus) isItem()    {}
+func (*Root) isItem()            {}
+func (*RootRef) isItem()         {}
+func (*SharedDataRef) isItem()   {}
+func (*UUIDMap) isItem()         {}
diff --git a/lib/btrfs/btrfstree/ops.go b/lib/btrfs/btrfstree/ops.go
index cdacef9..bda4ac8 100644
--- a/lib/btrfs/btrfstree/ops.go
+++ b/lib/btrfs/btrfstree/ops.go
@@ -207,7 +207,7 @@ func (fs TreeOperatorImpl) treeWalk(ctx context.Context, path TreePath, errHandl
 				ToKey:       item.Key,
 				ToMaxKey:    item.Key,
 			})
-			if errBody, isErr := item.Body.(btrfsitem.Error); isErr {
+			if errBody, isErr := item.Body.(*btrfsitem.Error); isErr {
 				if cbs.BadItem == nil {
 					errHandle(&TreeError{Path: itemPath, Err: errBody.Err})
 				} else {
diff --git a/lib/btrfs/btrfstree/root.go b/lib/btrfs/btrfstree/root.go
index 319904b..ace2b49 100644
--- a/lib/btrfs/btrfstree/root.go
+++ b/lib/btrfs/btrfstree/root.go
@@ -72,14 +72,14 @@ func LookupTreeRoot(fs TreeOperator, sb Superblock, treeID btrfsprim.ObjID) (*Tr
 			return nil, err
 		}
 		switch rootItemBody := rootItem.Body.(type) {
-		case btrfsitem.Root:
+		case *btrfsitem.Root:
 			return &TreeRoot{
 				TreeID:     treeID,
 				RootNode:   rootItemBody.ByteNr,
 				Level:      rootItemBody.Level,
 				Generation: rootItemBody.Generation,
 			}, nil
-		case btrfsitem.Error:
+		case *btrfsitem.Error:
 			return nil, fmt.Errorf("malformed ROOT_ITEM for tree %v: %w", treeID, rootItemBody.Err)
 		default:
 			panic(fmt.Errorf("should not happen: ROOT_ITEM has unexpected item type: %T", rootItemBody))
diff --git a/lib/btrfs/csums.go b/lib/btrfs/csums.go
index a32f090..2bfa588 100644
--- a/lib/btrfs/csums.go
+++ b/lib/btrfs/csums.go
@@ -60,9 +60,9 @@ func LookupCSum(fs btrfstree.TreeOperator, alg btrfssum.CSumType, laddr btrfsvol
 		return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, fmt.Errorf("item type is %v, not EXTENT_CSUM", item.Key.ItemType)
 	}
 	switch body := item.Body.(type) {
-	case btrfsitem.ExtentCSum:
+	case *btrfsitem.ExtentCSum:
 		return body.SumRun, nil
-	case btrfsitem.Error:
+	case *btrfsitem.Error:
 		return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, body.Err
 	default:
 		panic(fmt.Errorf("should not happen: EXTENT_CSUM has unexpected item type: %T", body))
diff --git a/lib/btrfs/io2_lv.go b/lib/btrfs/io2_lv.go
index ac7ea70..856ac20 100644
--- a/lib/btrfs/io2_lv.go
+++ b/lib/btrfs/io2_lv.go
@@ -173,13 +173,13 @@ func (fs *FS) initDev(ctx context.Context, sb btrfstree.Superblock) error {
 					return nil
 				}
 				switch itemBody := item.Body.(type) {
-				case btrfsitem.Chunk:
+				case *btrfsitem.Chunk:
 					for _, mapping := range itemBody.Mappings(item.Key) {
 						if err := fs.LV.AddMapping(mapping); err != nil {
 							return err
 						}
 					}
-				case btrfsitem.Error:
+				case *btrfsitem.Error:
 					// do nothing
 				default:
 					// This is a panic because the item decoder should not emit CHUNK_ITEM items as
diff --git a/lib/btrfs/io3_btree.go b/lib/btrfs/io3_btree.go
index 8ec4b41..18df98e 100644
--- a/lib/btrfs/io3_btree.go
+++ b/lib/btrfs/io3_btree.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -43,7 +43,7 @@ func (fs *FS) populateTreeUUIDs(ctx context.Context) {
 			},
 			btrfstree.TreeWalkHandler{
 				Item: func(_ btrfstree.TreePath, item btrfstree.Item) error {
-					itemBody, ok := item.Body.(btrfsitem.Root)
+					itemBody, ok := item.Body.(*btrfsitem.Root)
 					if !ok {
 						return nil
 					}
diff --git a/lib/btrfs/io4_fs.go b/lib/btrfs/io4_fs.go
index adc0928..c21cafc 100644
--- a/lib/btrfs/io4_fs.go
+++ b/lib/btrfs/io4_fs.go
@@ -88,9 +88,9 @@ func (sv *Subvolume) init() {
 			sv.rootErr = err
 		} else {
 			switch rootBody := root.Body.(type) {
-			case btrfsitem.Root:
-				sv.rootVal = rootBody
-			case btrfsitem.Error:
+			case *btrfsitem.Root:
+				sv.rootVal = *rootBody
+			case *btrfsitem.Error:
 				sv.rootErr = fmt.Errorf("FS_TREE ROOT_ITEM has malformed body: %w", rootBody.Err)
 			default:
 				panic(fmt.Errorf("should not happen: ROOT_ITEM has unexpected item type: %T", rootBody))
@@ -126,9 +126,10 @@ func (sv *Subvolume) LoadBareInode(inode btrfsprim.ObjID) (*BareInode, error) {
 		}
 
 		switch itemBody := item.Body.(type) {
-		case btrfsitem.Inode:
-			val.InodeItem = &itemBody
-		case btrfsitem.Error:
+		case *btrfsitem.Inode:
+			bodyCopy := *itemBody
+			val.InodeItem = &bodyCopy
+		case *btrfsitem.Error:
 			val.Errs = append(val.Errs, fmt.Errorf("malformed inode: %w", itemBody.Err))
 		default:
 			panic(fmt.Errorf("should not happen: INODE_ITEM has unexpected item type: %T", itemBody))
@@ -164,24 +165,25 @@ func (sv *Subvolume) LoadFullInode(inode btrfsprim.ObjID) (*FullInode, error) {
 			switch item.Key.ItemType {
 			case btrfsitem.INODE_ITEM_KEY:
 				switch itemBody := item.Body.(type) {
-				case btrfsitem.Inode:
+				case *btrfsitem.Inode:
 					if val.InodeItem != nil {
 						if !reflect.DeepEqual(itemBody, *val.InodeItem) {
 							val.Errs = append(val.Errs, fmt.Errorf("multiple inodes"))
 						}
 						continue
 					}
-					val.InodeItem = &itemBody
-				case btrfsitem.Error:
+					bodyCopy := *itemBody
+					val.InodeItem = &bodyCopy
+				case *btrfsitem.Error:
 					val.Errs = append(val.Errs, fmt.Errorf("malformed INODE_ITEM: %w", itemBody.Err))
 				default:
 					panic(fmt.Errorf("should not happen: INODE_ITEM has unexpected item type: %T", itemBody))
 				}
 			case btrfsitem.XATTR_ITEM_KEY:
 				switch itemBody := item.Body.(type) {
-				case btrfsitem.DirEntry:
+				case *btrfsitem.DirEntry:
 					val.XAttrs[string(itemBody.Name)] = string(itemBody.Data)
-				case btrfsitem.Error:
+				case *btrfsitem.Error:
 					val.Errs = append(val.Errs, fmt.Errorf("malformed XATTR_ITEM: %w", itemBody.Err))
 				default:
 					panic(fmt.Errorf("should not happen: XATTR_ITEM has unexpected item type: %T", itemBody))
@@ -225,15 +227,15 @@ func (dir *Dir) populate() {
 		switch item.Key.ItemType {
 		case btrfsitem.INODE_REF_KEY:
 			switch body := item.Body.(type) {
-			case btrfsitem.InodeRefs:
-				if len(body) != 1 {
+			case *btrfsitem.InodeRefs:
+				if len(body.Refs) != 1 {
 					dir.Errs = append(dir.Errs, fmt.Errorf("INODE_REF item with %d entries on a directory",
-						len(body)))
+						len(body.Refs)))
 					continue
 				}
 				ref := InodeRef{
 					Inode:    btrfsprim.ObjID(item.Key.Offset),
-					InodeRef: body[0],
+					InodeRef: body.Refs[0],
 				}
 				if dir.DotDot != nil {
 					if !reflect.DeepEqual(ref, *dir.DotDot) {
@@ -242,14 +244,14 @@ func (dir *Dir) populate() {
 					continue
 				}
 				dir.DotDot = &ref
-			case btrfsitem.Error:
+			case *btrfsitem.Error:
 				dir.Errs = append(dir.Errs, fmt.Errorf("malformed INODE_REF: %w", body.Err))
 			default:
 				panic(fmt.Errorf("should not happen: INODE_REF has unexpected item type: %T", body))
 			}
 		case btrfsitem.DIR_ITEM_KEY:
 			switch entry := item.Body.(type) {
-			case btrfsitem.DirEntry:
+			case *btrfsitem.DirEntry:
 				namehash := btrfsitem.NameHash(entry.Name)
 				if namehash != item.Key.Offset {
 					dir.Errs = append(dir.Errs, fmt.Errorf("direntry crc32c mismatch: key=%#x crc32c(%q)=%#x",
@@ -262,8 +264,8 @@ func (dir *Dir) populate() {
 					}
 					continue
 				}
-				dir.ChildrenByName[string(entry.Name)] = entry
-			case btrfsitem.Error:
+				dir.ChildrenByName[string(entry.Name)] = *entry
+			case *btrfsitem.Error:
 				dir.Errs = append(dir.Errs, fmt.Errorf("malformed DIR_ITEM: %w", entry.Err))
 			default:
 				panic(fmt.Errorf("should not happen: DIR_ITEM has unexpected item type: %T", entry))
@@ -271,15 +273,15 @@ func (dir *Dir) populate() {
 		case btrfsitem.DIR_INDEX_KEY:
 			index := item.Key.Offset
 			switch entry := item.Body.(type) {
-			case btrfsitem.DirEntry:
+			case *btrfsitem.DirEntry:
 				if other, exists := dir.ChildrenByIndex[index]; exists {
 					if !reflect.DeepEqual(entry, other) {
 						dir.Errs = append(dir.Errs, fmt.Errorf("multiple instances of direntry index %v", index))
 					}
 					continue
 				}
-				dir.ChildrenByIndex[index] = entry
-			case btrfsitem.Error:
+				dir.ChildrenByIndex[index] = *entry
+			case *btrfsitem.Error:
 				dir.Errs = append(dir.Errs, fmt.Errorf("malformed DIR_INDEX: %w", entry.Err))
 			default:
 				panic(fmt.Errorf("should not happen: DIR_INDEX has unexpected item type: %T", entry))
@@ -361,12 +363,12 @@ func (file *File) populate() {
 			// TODO
 		case btrfsitem.EXTENT_DATA_KEY:
 			switch itemBody := item.Body.(type) {
-			case btrfsitem.FileExtent:
+			case *btrfsitem.FileExtent:
 				file.Extents = append(file.Extents, FileExtent{
 					OffsetWithinFile: int64(item.Key.Offset),
-					FileExtent:       itemBody,
+					FileExtent:       *itemBody,
 				})
-			case btrfsitem.Error:
+			case *btrfsitem.Error:
 				file.Errs = append(file.Errs, fmt.Errorf("malformed EXTENT_DATA: %w", itemBody.Err))
 			default:
 				panic(fmt.Errorf("should not happen: EXTENT_DATA has unexpected item type: %T", itemBody))
diff --git a/lib/btrfsprogs/btrfsinspect/print_tree.go b/lib/btrfsprogs/btrfsinspect/print_tree.go
index 3807df5..409ce0c 100644
--- a/lib/btrfsprogs/btrfsinspect/print_tree.go
+++ b/lib/btrfsprogs/btrfsinspect/print_tree.go
@@ -121,11 +121,11 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				itemOffset,
 				itemSize)
 			switch body := item.Body.(type) {
-			case btrfsitem.FreeSpaceHeader:
+			case *btrfsitem.FreeSpaceHeader:
 				textui.Fprintf(out, "\t\tlocation %v\n", fmtKey(body.Location))
 				textui.Fprintf(out, "\t\tcache generation %v entries %v bitmaps %v\n",
 					body.Generation, body.NumEntries, body.NumBitmaps)
-			case btrfsitem.Inode:
+			case *btrfsitem.Inode:
 				textui.Fprintf(out, ""+
 					"\t\tgeneration %v transid %v size %v nbytes %v\n"+
 					"\t\tblock group %v mode %o links %v uid %v gid %v rdev %v\n"+
@@ -137,14 +137,14 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				textui.Fprintf(out, "\t\tctime %v\n", fmtTime(body.CTime))
 				textui.Fprintf(out, "\t\tmtime %v\n", fmtTime(body.MTime))
 				textui.Fprintf(out, "\t\totime %v\n", fmtTime(body.OTime))
-			case btrfsitem.InodeRefs:
-				for _, ref := range body {
+			case *btrfsitem.InodeRefs:
+				for _, ref := range body.Refs {
 					textui.Fprintf(out, "\t\tindex %v namelen %v name: %s\n",
 						ref.Index, ref.NameLen, ref.Name)
 				}
 			// case btrfsitem.INODE_EXTREF_KEY:
 			// 	// TODO
-			case btrfsitem.DirEntry:
+			case *btrfsitem.DirEntry:
 				textui.Fprintf(out, "\t\tlocation %v type %v\n",
 					fmtKey(body.Location), body.Type)
 				textui.Fprintf(out, "\t\ttransid %v data_len %v name_len %v\n",
@@ -155,7 +155,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				}
 			// case btrfsitem.DIR_LOG_INDEX_KEY, btrfsitem.DIR_LOG_ITEM_KEY:
 			// 	// TODO
-			case btrfsitem.Root:
+			case *btrfsitem.Root:
 				textui.Fprintf(out, "\t\tgeneration %v root_dirid %v bytenr %d byte_limit %v bytes_used %v\n",
 					body.Generation, body.RootDirID, body.ByteNr, body.ByteLimit, body.BytesUsed)
 				textui.Fprintf(out, "\t\tlast_snapshot %v flags %v refs %v\n",
@@ -175,7 +175,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 					textui.Fprintf(out, "\t\tstime %v\n", fmtTime(body.STime))
 					textui.Fprintf(out, "\t\trtime %v\n", fmtTime(body.RTime))
 				}
-			case btrfsitem.RootRef:
+			case *btrfsitem.RootRef:
 				var tag string
 				switch item.Key.ItemType {
 				case btrfsitem.ROOT_REF_KEY:
@@ -187,7 +187,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				}
 				textui.Fprintf(out, "\t\troot %v key dirid %v sequence %v name %s\n",
 					tag, body.DirID, body.Sequence, body.Name)
-			case btrfsitem.Extent:
+			case *btrfsitem.Extent:
 				textui.Fprintf(out, "\t\trefs %v gen %v flags %v\n",
 					body.Head.Refs, body.Head.Generation, body.Head.Flags)
 				if body.Head.Flags.Has(btrfsitem.EXTENT_FLAG_TREE_BLOCK) {
@@ -195,7 +195,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 						fmtKey(body.Info.Key), body.Info.Level)
 				}
 				printExtentInlineRefs(out, body.Refs)
-			case btrfsitem.Metadata:
+			case *btrfsitem.Metadata:
 				textui.Fprintf(out, "\t\trefs %v gen %v flags %v\n",
 					body.Head.Refs, body.Head.Generation, body.Head.Flags)
 				textui.Fprintf(out, "\t\ttree block skinny level %v\n", item.Key.Offset)
@@ -204,7 +204,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 			// 	// TODO
 			// case btrfsitem.SHARED_DATA_REF_KEY:
 			// 	// TODO
-			case btrfsitem.ExtentCSum:
+			case *btrfsitem.ExtentCSum:
 				start := btrfsvol.LogicalAddr(item.Key.Offset)
 				textui.Fprintf(out, "\t\trange start %d end %d length %d",
 					start, start.Add(body.Size()), body.Size())
@@ -222,7 +222,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 					return nil
 				})
 				textui.Fprintf(out, "\n")
-			case btrfsitem.FileExtent:
+			case *btrfsitem.FileExtent:
 				textui.Fprintf(out, "\t\tgeneration %v type %v\n",
 					body.Generation, body.Type)
 				switch body.Type {
@@ -249,15 +249,15 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				default:
 					textui.Fprintf(out, "\t\t(error) unknown file extent type %v", body.Type)
 				}
-			case btrfsitem.BlockGroup:
+			case *btrfsitem.BlockGroup:
 				textui.Fprintf(out, "\t\tblock group used %v chunk_objectid %v flags %v\n",
 					body.Used, body.ChunkObjectID, body.Flags)
-			case btrfsitem.FreeSpaceInfo:
+			case *btrfsitem.FreeSpaceInfo:
 				textui.Fprintf(out, "\t\tfree space info extent count %v flags %d\n",
 					body.ExtentCount, body.Flags)
-			case btrfsitem.FreeSpaceBitmap:
+			case *btrfsitem.FreeSpaceBitmap:
 				textui.Fprintf(out, "\t\tfree space bitmap\n")
-			case btrfsitem.Chunk:
+			case *btrfsitem.Chunk:
 				textui.Fprintf(out, "\t\tlength %d owner %d stripe_len %v type %v\n",
 					body.Head.Size, body.Head.Owner, body.Head.StripeLen, body.Head.Type)
 				textui.Fprintf(out, "\t\tio_align %v io_width %v sector_size %v\n",
@@ -270,7 +270,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 					textui.Fprintf(out, "\t\t\tdev_uuid %v\n",
 						stripe.DeviceUUID)
 				}
-			case btrfsitem.Dev:
+			case *btrfsitem.Dev:
 				textui.Fprintf(out, ""+
 					"\t\tdevid %d total_bytes %v bytes_used %v\n"+
 					"\t\tio_align %v io_width %v sector_size %v type %v\n"+
@@ -284,18 +284,18 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 					body.SeekSpeed, body.Bandwidth,
 					body.DevUUID,
 					body.FSUUID)
-			case btrfsitem.DevExtent:
+			case *btrfsitem.DevExtent:
 				textui.Fprintf(out, ""+
 					"\t\tdev extent chunk_tree %d\n"+
 					"\t\tchunk_objectid %v chunk_offset %d length %d\n"+
 					"\t\tchunk_tree_uuid %v\n",
 					body.ChunkTree, body.ChunkObjectID, body.ChunkOffset, body.Length,
 					body.ChunkTreeUUID)
-			case btrfsitem.QGroupStatus:
+			case *btrfsitem.QGroupStatus:
 				textui.Fprintf(out, ""+
 					"\t\tversion %v generation %v flags %v scan %d\n",
 					body.Version, body.Generation, body.Flags, body.RescanProgress)
-			case btrfsitem.QGroupInfo:
+			case *btrfsitem.QGroupInfo:
 				textui.Fprintf(out, ""+
 					"\t\tgeneration %v\n"+
 					"\t\treferenced %d referenced_compressed %d\n"+
@@ -303,7 +303,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 					body.Generation,
 					body.ReferencedBytes, body.ReferencedBytesCompressed,
 					body.ExclusiveBytes, body.ExclusiveBytesCompressed)
-			case btrfsitem.QGroupLimit:
+			case *btrfsitem.QGroupLimit:
 				textui.Fprintf(out, ""+
 					"\t\tflags %x\n"+
 					"\t\tmax_referenced %d max_exclusive %d\n"+
@@ -311,11 +311,11 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 					uint64(body.Flags),
 					body.MaxReferenced, body.MaxExclusive,
 					body.RsvReferenced, body.RsvExclusive)
-			case btrfsitem.UUIDMap:
+			case *btrfsitem.UUIDMap:
 				textui.Fprintf(out, "\t\tsubvol_id %d\n", body.ObjID)
 			// case btrfsitem.STRING_ITEM_KEY:
 			// 	// TODO
-			case btrfsitem.DevStats:
+			case *btrfsitem.DevStats:
 				textui.Fprintf(out, "\t\tpersistent item objectid %v offset %v\n",
 					item.Key.ObjectID.Format(item.Key.ItemType), item.Key.Offset)
 				switch item.Key.ObjectID {
@@ -332,7 +332,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				}
 			// case btrfsitem.TEMPORARY_ITEM_KEY:
 			// 	// TODO
-			case btrfsitem.Empty:
+			case *btrfsitem.Empty:
 				switch item.Key.ItemType {
 				case btrfsitem.ORPHAN_ITEM_KEY: // 48
 					textui.Fprintf(out, "\t\torphan item\n")
@@ -351,7 +351,7 @@ func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfspri
 				default:
 					textui.Fprintf(out, "\t\t(error) unhandled empty item type: %v\n", item.Key.ItemType)
 				}
-			case btrfsitem.Error:
+			case *btrfsitem.Error:
 				textui.Fprintf(out, "\t\t(error) error item: %v\n", body.Err)
 			default:
 				textui.Fprintf(out, "\t\t(error) unhandled item type: %T\n", body)
@@ -423,10 +423,10 @@ func printExtentInlineRefs(out io.Writer, refs []btrfsitem.ExtentInlineRef) {
 			default:
 				textui.Fprintf(out, "\t\t(error) unexpected empty sub-item type: %v\n", ref.Type)
 			}
-		case btrfsitem.ExtentDataRef:
+		case *btrfsitem.ExtentDataRef:
 			textui.Fprintf(out, "\t\textent data backref root %v objectid %v offset %v count %v\n",
 				subitem.Root, subitem.ObjectID, subitem.Offset, subitem.Count)
-		case btrfsitem.SharedDataRef:
+		case *btrfsitem.SharedDataRef:
 			textui.Fprintf(out, "\t\tshared data backref parent %v count %v\n",
 				ref.Offset, subitem.Count)
 		default:
diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/graph/graph.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/graph/graph.go
index cf86d74..c04fec0 100644
--- a/lib/btrfsprogs/btrfsinspect/rebuildnodes/graph/graph.go
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/graph/graph.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -151,7 +151,7 @@ func (g Graph) InsertNode(nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.No
 	if nodeRef.Data.Head.Level == 0 {
 		cnt := 0
 		for _, item := range nodeRef.Data.BodyLeaf {
-			if _, ok := item.Body.(btrfsitem.Root); ok {
+			if _, ok := item.Body.(*btrfsitem.Root); ok {
 				cnt++
 			}
 		}
@@ -161,7 +161,7 @@ func (g Graph) InsertNode(nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.No
 		g.Nodes[nodeRef.Addr] = nodeData
 		for i, item := range nodeRef.Data.BodyLeaf {
 			keys[i] = item.Key
-			if itemBody, ok := item.Body.(btrfsitem.Root); ok {
+			if itemBody, ok := item.Body.(*btrfsitem.Root); ok {
 				kps = append(kps, Edge{
 					FromRoot:     nodeRef.Addr,
 					FromItem:     i,
diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go
index a85b78e..149706d 100644
--- a/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go
@@ -73,27 +73,27 @@ func (o *Handle) InsertNode(nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.
 			Idx:  i,
 		}
 		switch itemBody := item.Body.(type) {
-		case btrfsitem.Inode:
+		case *btrfsitem.Inode:
 			o.Flags[ptr] = FlagsAndErr{
 				NoDataSum: itemBody.Flags.Has(btrfsitem.INODE_NODATASUM),
 				Err:       nil,
 			}
-		case btrfsitem.DirEntry:
+		case *btrfsitem.DirEntry:
 			if item.Key.ItemType == btrfsprim.DIR_INDEX_KEY {
 				o.Names[ptr] = append([]byte(nil), itemBody.Name...)
 			}
-		case btrfsitem.ExtentCSum:
+		case *btrfsitem.ExtentCSum:
 			o.Sizes[ptr] = SizeAndErr{
 				Size: uint64(itemBody.Size()),
 				Err:  nil,
 			}
-		case btrfsitem.FileExtent:
+		case *btrfsitem.FileExtent:
 			size, err := itemBody.Size()
 			o.Sizes[ptr] = SizeAndErr{
 				Size: uint64(size),
 				Err:  err,
 			}
-		case btrfsitem.Error:
+		case *btrfsitem.Error:
 			switch item.Key.ItemType {
 			case btrfsprim.INODE_ITEM_KEY:
 				o.Flags[ptr] = FlagsAndErr{
diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go
index bd29278..624441f 100644
--- a/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go
@@ -290,9 +290,9 @@ func (o *rebuilder) cbLookupRoot(ctx context.Context, tree btrfsprim.ObjID) (off
 		o.ioErr(ctx, fmt.Errorf("could not read previously read item: %v", key))
 	}
 	switch itemBody := itemBody.(type) {
-	case btrfsitem.Root:
-		return btrfsprim.Generation(key.Offset), itemBody, true
-	case btrfsitem.Error:
+	case *btrfsitem.Root:
+		return btrfsprim.Generation(key.Offset), *itemBody, true
+	case *btrfsitem.Error:
 		o.fsErr(ctx, fmt.Errorf("error decoding item: %v: %w", key, itemBody.Err))
 		return 0, btrfsitem.Root{}, false
 	default:
@@ -315,9 +315,9 @@ func (o *rebuilder) cbLookupUUID(ctx context.Context, uuid btrfsprim.UUID) (id b
 		o.ioErr(ctx, fmt.Errorf("could not read previously read item: %v", key))
 	}
 	switch itemBody := itemBody.(type) {
-	case btrfsitem.UUIDMap:
+	case *btrfsitem.UUIDMap:
 		return itemBody.ObjID, true
-	case btrfsitem.Error:
+	case *btrfsitem.Error:
 		o.fsErr(ctx, fmt.Errorf("error decoding item: %v: %w", key, itemBody.Err))
 		return 0, false
 	default:
diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild_graph.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild_graph.go
index 9e40465..710030c 100644
--- a/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild_graph.go
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild_graph.go
@@ -50,7 +50,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 	// https://btrfs.wiki.kernel.org/index.php/File:References.png (from the page
 	// https://btrfs.wiki.kernel.org/index.php/Data_Structures )
 	switch body := item.Body.(type) {
-	case btrfsitem.BlockGroup:
+	case *btrfsitem.BlockGroup:
 		o.want(ctx, "Chunk",
 			btrfsprim.CHUNK_TREE_OBJECTID,
 			body.ChunkObjectID,
@@ -60,22 +60,22 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 			item.Key.ObjectID,
 			btrfsitem.FREE_SPACE_INFO_KEY,
 			item.Key.Offset)
-	case btrfsitem.Chunk:
+	case *btrfsitem.Chunk:
 		o.want(ctx, "owning Root",
 			btrfsprim.ROOT_TREE_OBJECTID,
 			body.Head.Owner,
 			btrfsitem.ROOT_ITEM_KEY)
-	case btrfsitem.Dev:
+	case *btrfsitem.Dev:
 		// nothing
-	case btrfsitem.DevExtent:
+	case *btrfsitem.DevExtent:
 		o.wantOff(ctx, "Chunk",
 			body.ChunkTree,
 			body.ChunkObjectID,
 			btrfsitem.CHUNK_ITEM_KEY,
 			uint64(body.ChunkOffset))
-	case btrfsitem.DevStats:
+	case *btrfsitem.DevStats:
 		// nothing
-	case btrfsitem.DirEntry:
+	case *btrfsitem.DirEntry:
 		// containing-directory
 		o.wantOff(ctx, "containing dir inode",
 			treeID,
@@ -126,9 +126,9 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				o.fsErr(ctx, fmt.Errorf("DirEntry: unexpected .Location.ItemType=%v", body.Location.ItemType))
 			}
 		}
-	case btrfsitem.Empty:
+	case *btrfsitem.Empty:
 		// nothing
-	case btrfsitem.Extent:
+	case *btrfsitem.Extent:
 		// if body.Head.Flags.Has(btrfsitem.EXTENT_FLAG_TREE_BLOCK) {
 		// 	// Supposedly this flag indicates that
 		// 	// body.Info.Key identifies a node by the
@@ -140,7 +140,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 			switch refBody := ref.Body.(type) {
 			case nil:
 				// nothing
-			case btrfsitem.ExtentDataRef:
+			case *btrfsitem.ExtentDataRef:
 				o.wantOff(ctx, "referencing Inode",
 					refBody.Root,
 					refBody.ObjectID,
@@ -151,7 +151,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 					refBody.ObjectID,
 					btrfsitem.EXTENT_DATA_KEY,
 					uint64(refBody.Offset))
-			case btrfsitem.SharedDataRef:
+			case *btrfsitem.SharedDataRef:
 				// nothing
 			default:
 				// This is a panic because the item decoder should not emit a new
@@ -159,9 +159,9 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				panic(fmt.Errorf("should not happen: Extent: unexpected .Refs[%d].Body type %T", i, refBody))
 			}
 		}
-	case btrfsitem.ExtentCSum:
+	case *btrfsitem.ExtentCSum:
 		// nothing
-	case btrfsitem.ExtentDataRef:
+	case *btrfsitem.ExtentDataRef:
 		o.want(ctx, "Extent being referenced",
 			btrfsprim.EXTENT_TREE_OBJECTID,
 			item.Key.ObjectID,
@@ -176,7 +176,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 			body.ObjectID,
 			btrfsitem.EXTENT_DATA_KEY,
 			uint64(body.Offset))
-	case btrfsitem.FileExtent:
+	case *btrfsitem.FileExtent:
 		o.wantOff(ctx, "containing Inode",
 			treeID,
 			item.Key.ObjectID,
@@ -194,19 +194,19 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 		default:
 			o.fsErr(ctx, fmt.Errorf("FileExtent: unexpected body.Type=%v", body.Type))
 		}
-	case btrfsitem.FreeSpaceBitmap:
+	case *btrfsitem.FreeSpaceBitmap:
 		o.wantOff(ctx, "FreeSpaceInfo",
 			treeID,
 			item.Key.ObjectID,
 			btrfsitem.FREE_SPACE_INFO_KEY,
 			item.Key.Offset)
-	case btrfsitem.FreeSpaceHeader:
+	case *btrfsitem.FreeSpaceHeader:
 		o.wantOff(ctx, ".Location",
 			treeID,
 			body.Location.ObjectID,
 			body.Location.ItemType,
 			body.Location.Offset)
-	case btrfsitem.FreeSpaceInfo:
+	case *btrfsitem.FreeSpaceInfo:
 		if body.Flags.Has(btrfsitem.FREE_SPACE_USING_BITMAPS) {
 			o.wantOff(ctx, "FreeSpaceBitmap",
 				treeID,
@@ -214,7 +214,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				btrfsitem.FREE_SPACE_BITMAP_KEY,
 				item.Key.Offset)
 		}
-	case btrfsitem.Inode:
+	case *btrfsitem.Inode:
 		o.want(ctx, "backrefs",
 			treeID, // TODO: validate the number of these against body.NLink
 			item.Key.ObjectID,
@@ -227,7 +227,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				body.BlockGroup,
 				btrfsitem.BLOCK_GROUP_ITEM_KEY)
 		}
-	case btrfsitem.InodeRefs:
+	case *btrfsitem.InodeRefs:
 		o.wantOff(ctx, "child Inode",
 			treeID,
 			item.Key.ObjectID,
@@ -238,7 +238,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 			btrfsprim.ObjID(item.Key.Offset),
 			btrfsitem.INODE_ITEM_KEY,
 			0)
-		for _, ref := range body {
+		for _, ref := range body.Refs {
 			o.wantOff(ctx, "DIR_ITEM",
 				treeID,
 				btrfsprim.ObjID(item.Key.Offset),
@@ -250,12 +250,12 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				btrfsitem.DIR_INDEX_KEY,
 				uint64(ref.Index))
 		}
-	case btrfsitem.Metadata:
+	case *btrfsitem.Metadata:
 		for i, ref := range body.Refs {
 			switch refBody := ref.Body.(type) {
 			case nil:
 				// nothing
-			case btrfsitem.ExtentDataRef:
+			case *btrfsitem.ExtentDataRef:
 				o.wantOff(ctx, "referencing INode",
 					refBody.Root,
 					refBody.ObjectID,
@@ -266,7 +266,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 					refBody.ObjectID,
 					btrfsitem.EXTENT_DATA_KEY,
 					uint64(refBody.Offset))
-			case btrfsitem.SharedDataRef:
+			case *btrfsitem.SharedDataRef:
 				// nothing
 			default:
 				// This is a panic because the item decoder should not emit a new
@@ -274,7 +274,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				panic(fmt.Errorf("should not happen: Metadata: unexpected .Refs[%d].Body type %T", i, refBody))
 			}
 		}
-	case btrfsitem.Root:
+	case *btrfsitem.Root:
 		if body.RootDirID != 0 {
 			o.wantOff(ctx, "root directory",
 				item.Key.ObjectID,
@@ -298,7 +298,7 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 				key.ItemType,
 				key.Offset)
 		}
-	case btrfsitem.RootRef:
+	case *btrfsitem.RootRef:
 		var otherType btrfsprim.ItemType
 		var parent, child btrfsprim.ObjID
 		switch item.Key.ItemType {
@@ -347,17 +347,17 @@ func handleItem(o rebuildCallbacks, ctx context.Context, treeID btrfsprim.ObjID,
 			treeID,
 			child,
 			btrfsitem.ROOT_ITEM_KEY)
-	case btrfsitem.SharedDataRef:
+	case *btrfsitem.SharedDataRef:
 		o.want(ctx, "Extent",
 			btrfsprim.EXTENT_TREE_OBJECTID,
 			item.Key.ObjectID,
 			btrfsitem.EXTENT_ITEM_KEY)
-	case btrfsitem.UUIDMap:
+	case *btrfsitem.UUIDMap:
 		o.want(ctx, "subvolume Root",
 			btrfsprim.ROOT_TREE_OBJECTID,
 			body.ObjID,
 			btrfsitem.ROOT_ITEM_KEY)
-	case btrfsitem.Error:
+	case *btrfsitem.Error:
 		o.fsErr(ctx, fmt.Errorf("error decoding item: %w", body.Err))
 	default:
 		// This is a panic because the item decoder should not emit new types without this
diff --git a/lib/btrfsprogs/btrfsinspect/scandevices.go b/lib/btrfsprogs/btrfsinspect/scandevices.go
index 9b8360c..91b5136 100644
--- a/lib/btrfsprogs/btrfsinspect/scandevices.go
+++ b/lib/btrfsprogs/btrfsinspect/scandevices.go
@@ -183,14 +183,14 @@ func ScanOneDevice(ctx context.Context, dev *btrfs.Device, sb btrfstree.Superblo
 					switch item.Key.ItemType {
 					case btrfsitem.CHUNK_ITEM_KEY:
 						switch itemBody := item.Body.(type) {
-						case btrfsitem.Chunk:
+						case *btrfsitem.Chunk:
 							dlog.Tracef(ctx, "node@%v: item %v: found chunk",
 								nodeRef.Addr, i)
 							result.FoundChunks = append(result.FoundChunks, btrfstree.SysChunk{
 								Key:   item.Key,
-								Chunk: itemBody,
+								Chunk: *itemBody,
 							})
-						case btrfsitem.Error:
+						case *btrfsitem.Error:
 							dlog.Errorf(ctx, "node@%v: item %v: error: malformed CHUNK_ITEM: %v",
 								nodeRef.Addr, i, itemBody.Err)
 						default:
@@ -198,14 +198,14 @@ func ScanOneDevice(ctx context.Context, dev *btrfs.Device, sb btrfstree.Superblo
 						}
 					case btrfsitem.BLOCK_GROUP_ITEM_KEY:
 						switch itemBody := item.Body.(type) {
-						case btrfsitem.BlockGroup:
+						case *btrfsitem.BlockGroup:
 							dlog.Tracef(ctx, "node@%v: item %v: found block group",
 								nodeRef.Addr, i)
 							result.FoundBlockGroups = append(result.FoundBlockGroups, SysBlockGroup{
 								Key: item.Key,
-								BG:  itemBody,
+								BG:  *itemBody,
 							})
-						case btrfsitem.Error:
+						case *btrfsitem.Error:
 							dlog.Errorf(ctx, "node@%v: item %v: error: malformed BLOCK_GROUP_ITEM: %v",
 								nodeRef.Addr, i, itemBody.Err)
 						default:
@@ -213,14 +213,14 @@ func ScanOneDevice(ctx context.Context, dev *btrfs.Device, sb btrfstree.Superblo
 						}
 					case btrfsitem.DEV_EXTENT_KEY:
 						switch itemBody := item.Body.(type) {
-						case btrfsitem.DevExtent:
+						case *btrfsitem.DevExtent:
 							dlog.Tracef(ctx, "node@%v: item %v: found dev extent",
 								nodeRef.Addr, i)
 							result.FoundDevExtents = append(result.FoundDevExtents, SysDevExtent{
 								Key:    item.Key,
-								DevExt: itemBody,
+								DevExt: *itemBody,
 							})
-						case btrfsitem.Error:
+						case *btrfsitem.Error:
 							dlog.Errorf(ctx, "node@%v: item %v: error: malformed DEV_EXTENT: %v",
 								nodeRef.Addr, i, itemBody.Err)
 						default:
@@ -228,14 +228,14 @@ func ScanOneDevice(ctx context.Context, dev *btrfs.Device, sb btrfstree.Superblo
 						}
 					case btrfsitem.EXTENT_CSUM_KEY:
 						switch itemBody := item.Body.(type) {
-						case btrfsitem.ExtentCSum:
+						case *btrfsitem.ExtentCSum:
 							dlog.Tracef(ctx, "node@%v: item %v: found csums",
 								nodeRef.Addr, i)
 							result.FoundExtentCSums = append(result.FoundExtentCSums, SysExtentCSum{
 								Generation: nodeRef.Data.Head.Generation,
-								Sums:       itemBody,
+								Sums:       *itemBody,
 							})
-						case btrfsitem.Error:
+						case *btrfsitem.Error:
 							dlog.Errorf(ctx, "node@%v: item %v: error: malformed is EXTENT_CSUM: %v",
 								nodeRef.Addr, i, itemBody.Err)
 						default: