.

wcfs/internal/xbtree/xbtreetest/kvdiff.go

+// Copyright (C) 2020-2021  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+package xbtreetest
+// kvdiff + friends
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// kvdiff returns difference in between kv1 and kv2.
+const DEL = "ø" // DEL means deletion
+type Δstring struct {
+	Old string
+	New string
+}
+func kvdiff(kv1, kv2 map[Key]string) map[Key]Δstring {
+	delta := map[Key]Δstring{}
+	keys := SetKey{}
+	for k := range kv1 { keys.Add(k) }
+	for k := range kv2 { keys.Add(k) }
+
+	for k := range keys {
+		v1, ok := kv1[k]
+		if !ok { v1 = DEL }
+		v2, ok := kv2[k]
+		if !ok { v2 = DEL }
+		if v1 != v2 {
+			delta[k] = Δstring{v1,v2}
+		}
+	}
+
+	return delta
+}
+
+// kvtxt returns string representation of {} kv.
+func kvtxt(kv map[Key]string) string {
+	if len(kv) == 0 {
+		return "ø"
+	}
+
+	keyv := []Key{}
+	for k := range kv { keyv = append(keyv, k) }
+	sort.Slice(keyv, func(i,j int) bool { return keyv[i] < keyv[j] })
+
+	sv := []string{}
+	for _, k := range keyv {
+		v := kv[k]
+		if strings.ContainsAny(v, " \n\t,:") {
+			panicf("[%v]=%q: invalid value", k, v)
+		}
+		sv = append(sv, fmt.Sprintf("%v:%s", k, v))
+	}
+
+	return strings.Join(sv, ",")
+}

wcfs/internal/xbtree/xbtreetest/kvdiff_test.go

+// Copyright (C) 2020-2021  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+package xbtreetest
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestKVDiff(t *testing.T) {
+	kv1 := map[Key]string{1:"a", 3:"c", 4:"d"}
+	kv2 := map[Key]string{1:"b",        4:"d", 5:"e"}
+	got  := kvdiff(kv1, kv2)
+	want := map[Key]Δstring{1:{"a","b"}, 3:{"c",DEL}, 5:{DEL,"e"}}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("error:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestKVTxt(t *testing.T) {
+	kv := map[Key]string{3:"hello", 1:"zzz", 4:"world"}
+	got  := kvtxt(kv)
+	want := "1:zzz,3:hello,4:world"
+	if got != want {
+		t.Fatalf("error:\ngot:  %q\nwant: %q", got, want)
+	}
+}

wcfs/internal/xbtree/xbtreetest/rtree.go

+// Copyright (C) 2020-2021  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+package xbtreetest
+
+import (
+	"fmt"
+	"sort"
+
+	"lab.nexedi.com/kirr/neo/go/zodb"
+)
+
+// RTree represents Tree node covering [lo, hi_] key range in its parent tree.
+// XXX actually no coverage here -> kill? -> change to just `path []zodb.Oid` in RBucket?
+type RTree struct {
+	oid    zodb.Oid
+	parent *RTree
+	// XXX +children?
+}
+
+// RBucket represents Bucket node covering [lo, hi_] key range in its Tree.
+// NOTE it is not [lo,hi) but [lo,hi_] instead to avoid overflow at KeyMax.
+type RBucket struct {
+	oid     zodb.Oid
+	parent  *RTree
+	lo, hi_ Key	// XXX -> KeyRange ?
+	kv      map[Key]string // bucket's k->v; values were ZBlk objects whose data is loaded instead.
+}
+
+// Path returns path to this bucket from tree root.
+func (rb *RBucket) Path() []zodb.Oid {
+	path := []zodb.Oid{rb.oid}
+	p := rb.parent
+	for p != nil {
+		path = append([]zodb.Oid{p.oid}, path...)
+		p = p.parent
+	}
+	return path
+}
+
+// RBucketSet represents set of buckets covering whole [-∞,∞) range.
+type RBucketSet []*RBucket // k↑
+
+
+// Get returns RBucket which covers key k.
+func (rbs RBucketSet) Get(k Key) *RBucket {
+	i := sort.Search(len(rbs), func(i int) bool {
+		return k <= rbs[i].hi_
+	})
+	if i == len(rbs) {
+		panicf("BUG: key %v not covered;  coverage: %s", k, rbs.coverage())
+	}
+
+	rb := rbs[i]
+	if !(rb.lo <= k && k <= rb.hi_) {
+		panicf("BUG: get(%v) -> [%v, %v];  coverage: %s", k, rb.lo, rb.hi_, rbs.coverage())
+	}
+
+	return rb
+}
+
+// coverage returns string representation of rbs coverage structure.
+func (rbs RBucketSet) coverage() string {
+	if len(rbs) == 0 {
+		return "ø"
+	}
+	s := ""
+	for _, rb := range rbs {
+		if s != "" {
+			s += " "
+		}
+		s += fmt.Sprintf("[%v, %v]", rb.lo, rb.hi_)
+	}
+	return s
+}
+
+// Flatten converts xkv with bucket structure into regular dict.
+func (xkv RBucketSet) Flatten() map[Key]string {
+	kv := make(map[Key]string)
+	for _, b := range xkv {
+		for k,v := range b.kv {
+			kv[k] = v
+		}
+	}
+	return kv
+}
+
+func (b *RBucket) String() string {
+	return fmt.Sprintf("%sB%s{%s}", KeyRange{b.lo, b.hi_}, b.oid, kvtxt(b.kv))
+}

wcfs/internal/xbtree/xbtreetest/treegen.go

+// Copyright (C) 2020-2021  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+package xbtreetest
+// treegen.go provides functionality:
+//
+//   - to commit a particular BTree topology into ZODB, and
+//   - to generate set of random tree topologies that all correspond to particular {k->v} dict.
+//
+// treegen.py is used as helper for both tasks.
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+
+	"lab.nexedi.com/kirr/go123/xerr"
+	"lab.nexedi.com/kirr/neo/go/zodb"
+)
+
+
+// TreeGenSrv represents connection to running `treegen ...` server.
+type TreeGenSrv struct {
+	argv      []string
+	pysrv     *exec.Cmd      // spawned `treegen ...`
+	pyin      io.WriteCloser // input to pysrv
+	pyoutRaw  io.ReadCloser  // output from pysrv
+	pyout     *bufio.Reader  // buffered ^^^
+}
+
+// TreeSrv represents connection to running `treegen trees` server.
+//
+// Create it with StartTreeSrv(zurl).
+// - Commit(treeTopology) -> tid
+type TreeSrv struct {
+	*TreeGenSrv
+	zurl	  string
+	treeRoot  zodb.Oid       // oid of the tree treegen works on
+	head      zodb.Tid       // last made commit
+}
+
+// AllStructsSrv represents connection to running `treegen allstructs` server.
+//
+// Create it with StartAllStructsSrv().
+// - AllStructs(maxdepth, maxsplit, n, seed, kv1, kv2)
+type AllStructsSrv struct {
+	*TreeGenSrv
+}
+
+// StartTreeGenSrv spawns `treegen ...` server.
+func StartTreeGenSrv(argv ...string) (_ *TreeGenSrv, hello string, err error) {
+	defer xerr.Contextf(&err, "treesrv %v: start", argv)
+
+	// spawn `treegen ...`
+	tg := &TreeGenSrv{argv: argv}
+	tg.pysrv = exec.Command("./testprog/treegen.py", argv...)
+	tg.pyin, err = tg.pysrv.StdinPipe()
+	if err != nil {
+		return nil, "", err
+	}
+	tg.pyoutRaw, err = tg.pysrv.StdoutPipe()
+	if err != nil {
+		return nil, "", err
+	}
+	tg.pyout = bufio.NewReader(tg.pyoutRaw)
+	tg.pysrv.Stderr = os.Stderr // no redirection
+
+	err = tg.pysrv.Start()
+	if err != nil {
+		return nil, "", err
+	}
+
+	// wait for hello message and return it
+	defer func() {
+		if err != nil {
+			tg.Close() // ignore error
+		}
+	}()
+	defer xerr.Context(&err, "handshake")
+	hello, err = tg.pyout.ReadString('\n')
+	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return nil, "", err
+	}
+	hello = strings.TrimSuffix(hello, "\n")
+
+	return tg, hello, nil
+}
+
+// Close shutdowns treegen server.
+func (tg *TreeGenSrv) Close() (err error) {
+	defer xerr.Contextf(&err, "treegen %v: close", tg.argv)
+
+	err1 := tg.pyin.Close()
+	err2 := tg.pyoutRaw.Close()
+	err3 := tg.pysrv.Wait()
+	return xerr.Merge(err1, err2, err3)
+}
+
+
+// StartTreeSrv spawns `treegen trees` server.
+func StartTreeSrv(zurl string) (_ *TreeSrv, err error) {
+	defer xerr.Contextf(&err, "tree.srv %s: start", zurl)
+	tgSrv, hello, err := StartTreeGenSrv("trees", zurl)
+	if err != nil {
+		return nil, err
+	}
+
+	tg := &TreeSrv{TreeGenSrv: tgSrv, zurl: zurl}
+	defer func() {
+		if err != nil {
+			tgSrv.Close() // ignore error
+		}
+	}()
+
+	// tree.srv start @<at> tree=<root>
+	defer xerr.Contextf(&err, "invalid hello %q", hello)
+	startRe := regexp.MustCompile(`^tree.srv start @([^ ]+) root=([^ ]+)$`)
+	m := startRe.FindStringSubmatch(hello)
+	if m == nil {
+		return nil, fmt.Errorf("unexpected format")
+	}
+	tg.head, err = zodb.ParseTid(m[1]) // <at>
+	if err != nil {
+		return nil, fmt.Errorf("tid: %s", err)
+	}
+	tg.treeRoot, err = zodb.ParseOid(m[2]) // <root>
+	if err != nil {
+		return nil, fmt.Errorf("root: %s", err)
+	}
+
+	return tg, nil
+}
+
+// StartAllStructsSrv spawns `treegen allstructs` server.
+func StartAllStructsSrv() (_ *AllStructsSrv, err error) {
+	defer xerr.Context(&err, "allstructs.srv: start")
+
+	tgSrv, hello, err := StartTreeGenSrv("allstructs")
+	if err != nil {
+		return nil, err
+	}
+
+	sg := &AllStructsSrv{TreeGenSrv: tgSrv}
+	defer func() {
+		if err != nil {
+			tgSrv.Close() // ignore error
+		}
+	}()
+
+	defer xerr.Contextf(&err, "invalid hello %q", hello)
+	if hello != "# allstructs.srv start" {
+		return nil, fmt.Errorf("unexpected format")
+	}
+
+	return sg, nil
+}
+
+
+// Commit creates new commit with underlying tree changed to specified tree topology.
+func (tg *TreeSrv) Commit(tree string) (_ zodb.Tid, err error) {
+	defer xerr.Contextf(&err, "tree.srv %s: commit %s", tg.zurl, tree)
+
+	_, err = io.WriteString(tg.pyin, tree + "\n")
+	if err != nil {
+		return zodb.InvalidTid, err
+	}
+
+	reply, err := tg.pyout.ReadString('\n')
+	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return zodb.InvalidTid, err
+	}
+	reply = strings.TrimSuffix(reply, "\n")
+
+	tid, err := zodb.ParseTid(reply)
+	if err != nil {
+		return zodb.InvalidTid, fmt.Errorf("invalid reply: %s", err)
+	}
+	tg.head = tid
+	return tid, nil
+}
+
+// AllStructs returns response from `treegen allstructs`
+func (tg *AllStructsSrv) AllStructs(kv map[Key]string, maxdepth, maxsplit, n int, seed int64) (_ []string, err error) {
+	req := fmt.Sprintf("%d %d %d/%d %s", maxdepth, maxsplit, n, seed, kvtxt(kv))
+	defer xerr.Contextf(&err, "allstructs.srv: %s ", req)
+
+	_, err = io.WriteString(tg.pyin, req + "\n")
+	if err != nil {
+		return nil, err
+	}
+
+	structv := []string{}
+	for {
+		reply, err := tg.pyout.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				err = io.ErrUnexpectedEOF
+			}
+			return nil, err
+		}
+		reply = strings.TrimSuffix(reply, "\n")
+
+		if reply == "# ----" {
+			return structv, nil // end of response
+		}
+		if strings.HasPrefix(reply, "#") {
+			continue // comment
+		}
+
+		structv = append(structv, reply)
+	}
+}

wcfs/internal/xbtree/xbtreetest/xbtreetest.go

+// Copyright (C) 2020-2021  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+// Package xbtreetest provides infrastructure for testing LOBTree with ZBlk values.
+package xbtreetest
+
+import (
+	"fmt"
+	"math"
+
+	"lab.nexedi.com/kirr/neo/go/zodb"
+	"lab.nexedi.com/kirr/neo/go/zodb/btree"
+
+	"lab.nexedi.com/nexedi/wendelin.core/wcfs/internal/set"
+//	"lab.nexedi.com/nexedi/wendelin.core/wcfs/internal/xbtree"
+)
+
+// XXX dup from xbtree  (to avoid import cycle)
+type Tree   = btree.LOBTree
+type Bucket = btree.LOBucket
+
+type Key  = int64
+const KeyMax Key = math.MaxInt64
+const KeyMin Key = math.MinInt64
+type SetKey = set.SetI64
+
+const VDEL  = zodb.InvalidOid
+
+
+func panicf(format string, argv ...interface{}) {
+	panic(fmt.Sprintf(format, argv...))
+}

wcfs/internal/zdata/δftail.go

@@ -19,6 +19,7 @@
 
 package zdata
 
+// XXX kill
 //go:generate ../set/gen-set zdata ZBigFile *ZBigFile zset_bigfile.go
 
 import (
@@ -38,6 +39,7 @@ import (
 )
 
 type SetI64 = set.SetI64
+type SetOid = set.SetOid
 
 // ΔFtail represents tail of revisional changes to files.
 //
@@ -78,7 +80,8 @@ type SetI64 = set.SetI64
 type ΔFtail struct {
 	// ΔFtail merges ΔBtail with history of ZBlk
 	δBtail  *xbtree.ΔBtail
-	fileIdx map[zodb.Oid]SetZBigFile // tree-root -> {} ZBigFile as of @head
+//	fileIdx map[zodb.Oid]SetZBigFile // tree-root -> {} ZBigFile as of @head
+	fileIdx map[zodb.Oid]SetOid // tree-root -> {} ZBigFile<oid> as of @head
 
 // XXX kill
 ///*
@@ -90,14 +93,16 @@ type ΔFtail struct {
 
 	// tracked ZBlk that are not yet taken into account in current vδF.
 	// grows on new track requests; flushes on queries and update.
-	trackNew map[*ZBigFile]map[zodb.Oid]*zblkInΔFtail // {} file -> {} oid -> zblk
+//	trackNew map[*ZBigFile]map[zodb.Oid]*zblkInΔFtail // {} file -> {} oid -> zblk
+	trackNew map[zodb.Oid]map[zodb.Oid]*zblkInΔFtail // {} root -> {} oid -> zblk
 //*/
 }
 
 // ΔF represents a change in files space.
 type ΔF struct {
 	Rev    zodb.Tid
-	ByFile map[*ZBigFile]*ΔFile // file -> δfile
+//	ByFile map[*ZBigFile]*ΔFile // file -> δfile
+	ByFile map[zodb.Oid]*ΔFile // file<oid> -> δfile
 }
 
 // ΔFile represents a change to one file.
@@ -120,7 +125,8 @@ type zblkInΔFtail struct {
 	//  tree nodes and for tree_root->file)
 
 	// with which files/blocks this ZBlk is associated with as of @head state
-	infile map[*ZBigFile]SetI64 // {} file -> set(#blk)
+//	infile map[*ZBigFile]SetI64 // {} file -> set(#blk)
+	inroot map[zodb.Oid]SetI64 // {} root -> set(#blk)
 }
 
 type _ZBlkInΔFtail interface { inΔFtail() *zblkInΔFtail }
@@ -136,8 +142,10 @@ func (z *zblkInΔFtail) inΔFtail() *zblkInΔFtail { return z }
 func NewΔFtail(at0 zodb.Tid, db *zodb.DB) *ΔFtail {
 	return &ΔFtail{
 		δBtail:   xbtree.NewΔBtail(at0, db),
-		fileIdx:  make(map[zodb.Oid]SetZBigFile),
-		trackNew: make(map[*ZBigFile]map[zodb.Oid]*zblkInΔFtail),
+//		fileIdx:  make(map[zodb.Oid]SetZBigFile),
+		fileIdx:  make(map[zodb.Oid]SetOid),
+//		trackNew: make(map[*ZBigFile]map[zodb.Oid]*zblkInΔFtail),
+		trackNew: make(map[zodb.Oid]map[zodb.Oid]*zblkInΔFtail),
 	}
 }
 
@@ -159,6 +167,7 @@ func (δFtail *ΔFtail) Tail() zodb.Tid { return δFtail.δBtail.Tail() }
 //
 // A root can be associated with several files (each provided on different Track call).
 func (δFtail *ΔFtail) Track(file *ZBigFile, blk int64, path []btree.LONode, zblk ZBlk) {
+	fileOid := file.POid()
 	if blk == -1 {
 		// XXX blk = ∞ from beginning ?
 		blk = xbtree.KeyMax
@@ -168,24 +177,29 @@ func (δFtail *ΔFtail) Track(file *ZBigFile, blk int64, path []btree.LONode, zb
 		panic(err) // XXX -> error? errctx
 	}
 	root := path[0].(*btree.LOBTree)
-	files, ok := δFtail.fileIdx[root.POid()]
+	rootOid := root.POid()
+	files, ok := δFtail.fileIdx[rootOid]
 	if !ok {
-		files = SetZBigFile{}
-		δFtail.fileIdx[root.POid()] = files
+		files = SetOid{}
+		δFtail.fileIdx[rootOid] = files
 	}
-	files.Add(file)
+	files.Add(fileOid)
 
 	// associate zblk with file, if it was not hole
 	if zblk != nil {
 		z := zblk.inΔFtail()
 		z.mu.Lock()
-		blocks, ok := z.infile[file]
+//		blocks, ok := z.infile[file]
+		blocks, ok := z.inroot[rootOid]
 		if !ok {
 			blocks = make(SetI64, 1)
-			if z.infile == nil {
-				z.infile = make(map[*ZBigFile]SetI64)
+//			if z.infile == nil {
+//				z.infile = make(map[*ZBigFile]SetI64)
+			if z.inroot == nil {
+				z.inroot = make(map[zodb.Oid]SetI64)
 			}
-			z.infile[file] = blocks
+//			z.infile[file] = blocks
+			z.inroot[rootOid] = blocks
 		}
 		blocks.Add(blk)
 		z.mu.Unlock()
@@ -193,10 +207,10 @@ func (δFtail *ΔFtail) Track(file *ZBigFile, blk int64, path []btree.LONode, zb
 		// XXX locking
 		if !ok {
 			// zblk was not associated with this file
-			zt := δFtail.trackNew[file]
+			zt := δFtail.trackNew[fileOid]
 			if zt == nil {
 				zt = make(map[zodb.Oid]*zblkInΔFtail, 1)
-				δFtail.trackNew[file] = zt
+				δFtail.trackNew[fileOid] = zt
 			}
 			zt[zblk.POid()] = z
 		}
@@ -233,7 +247,7 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit, zhead *xzodb.ZConn) (_ ΔF
 		return ΔF{}, err
 	}
 
-	δF := ΔF{Rev: δB.Rev, ByFile: make(map[*ZBigFile]*ΔFile)}
+	δF := ΔF{Rev: δB.Rev, ByFile: make(map[zodb.Oid]*ΔFile)}
 
 	// take btree changes into account
 	for root, δt := range δB.ΔByRoot {
@@ -315,16 +329,18 @@ func (δFtail *ΔFtail) update(file *ZBigFile) {
 		panic("TODO")
 	}
 
+	fileOid := file.POid()
+
 	// let's see if we need to rebuild .vδF due to not-yet processed track requests
 
 	// XXX locking
 	// XXX dumb
-	zt, dirty := δFtail.trackNew[file]
+	zt, dirty := δFtail.trackNew[fileOid]
 	if !dirty {
 		return
 	}
 
-	delete(δFtail.trackNew, file)
+	delete(δFtail.trackNew, fileOid)
 	// XXX unlock here
 
 	for i, δZ := range δFtail.δBtail.ΔZtail().Data() {
@@ -339,13 +355,13 @@ func (δFtail *ΔFtail) update(file *ZBigFile) {
 
 			// XXX locking
 			// XXX -> func δF.δfile(file) ?
-			δfile, ok := δF.ByFile[file]
+			δfile, ok := δF.ByFile[fileOid]
 			if !ok {
 				δfile = &ΔFile{Rev: δF.Rev, Blocks: make(SetI64)}
-				δF.ByFile[file] = δfile
+				δF.ByFile[fileOid] = δfile
 			}
 
-			δfile.Blocks.Update(z.infile[file])
+			δfile.Blocks.Update(z.infile[fileOid])
 		}
 	}
 }
@@ -376,6 +392,8 @@ func (δFtail *ΔFtail) SliceByFileRev(file *ZBigFile, lo, hi zodb.Tid) /*readon
 	// FIXME rework to just query .δBtail.SliceByRootRev(file.blktab, lo, hi) +
 	//       merge δZBlk history with that.
 
+	foid := file.POid()
+
 	// XXX locking?
 	δFtail.update(file)
 
@@ -403,7 +421,7 @@ func (δFtail *ΔFtail) SliceByFileRev(file *ZBigFile, lo, hi zodb.Tid) /*readon
 	// filter found changed to have only file-related bits
 	var vδfile []*ΔFile
 	for _, δF := range vδF {
-		δfile, ok := δF.ByFile[file]
+		δfile, ok := δF.ByFile[foid]
 		if ok {
 			vδfile = append(vδfile, δfile)
 		}

wcfs/wcfs.go

@@ -882,7 +882,7 @@ retry:
 	if log.V(2) {
 		// debug dump δF
 		log.Infof("\n\nS: handleδZ: δF (#%d):\n", len(δF.ByFile))
-		for zfile, δfile := range δF.ByFile {
+		for zfileOid, δfile := range δF.ByFile {
 			blkv := δfile.Blocks.Elements()
 			sort.Slice(blkv, func(i, j int) bool {
 				return blkv[i] < blkv[j]
@@ -891,19 +891,19 @@ retry:
 			if δfile.Size {
 				size = "S"
 			}
-			log.Infof("S: \t- %s\t%s %v\n", zfile.POid(), size, blkv)
+			log.Infof("S: \t- %s\t%s %v\n", zfileOid, size, blkv)
 		}
 		log.Infof("\n\n")
 	}
 
 	wg := xsync.NewWorkGroup(ctx)
-	for zfile, δfile := range δF.ByFile {
+	for zfileOid, δfile := range δF.ByFile {
 //		// XXX needed?
 //		// XXX even though δBtail is complete, not all ZBlk are present here
 //		file.δtail.Append(δF.Rev, δfile.Blocks.Elements())
 
 		// zfile was requested to be tracked -> it must be present in fileTab
-		file := bfdir.fileTab[zfile.POid()]
+		file := bfdir.fileTab[zfileOid]
 		for blk := range δfile.Blocks {
 			blk := blk
 			wg.Go(func(ctx context.Context) error {