feat: fs-repo-11-to-12 special flatfs handling

fs-repo-11-to-12/go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/ipfs/go-cid v0.0.7
 	github.com/ipfs/go-datastore v0.4.5
 	github.com/ipfs/go-ds-badger v0.2.7-0.20220117180822-159330558612 // indirect
+	github.com/ipfs/go-ds-flatfs v0.4.5
 	github.com/ipfs/go-filestore v1.0.0
 	github.com/ipfs/go-ipfs v0.8.0
 	github.com/ipfs/go-ipfs-ds-help v1.0.0

fs-repo-11-to-12/migration/setup.go

@@ -2,10 +2,13 @@ package mg11
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
+	"reflect"
+	"unsafe"
 
 	ipfslite "github.com/hsanjuan/ipfs-lite"
 	migrate "github.com/ipfs/fs-repo-migrations/tools/go-migrate"
@@ -18,6 +21,9 @@ import (
 	loader "github.com/ipfs/go-ipfs/plugin/loader"
 	fsrepo "github.com/ipfs/go-ipfs/repo/fsrepo"
 	format "github.com/ipfs/go-ipld-format"
+
+	"github.com/ipfs/go-datastore/mount"
+	flatfs "github.com/ipfs/go-ds-flatfs"
 )
 
 // locks the repo
@@ -83,6 +89,58 @@ func (m *Migration) open(opts migrate.Options) error {
 	return nil
 }
 
+func getUnexportedField(field reflect.Value) interface{} {
+	return reflect.NewAt(field.Type(), unsafe.Pointer(field.UnsafeAddr())).Elem().Interface()
+}
+
+func IsDefaultConfig(dstore ds.Datastore) (dsPath string, v1 *flatfs.ShardIdV1, err error) {
+	errNotDefault := errors.New("not the default config")
+	defer func() {
+		if err := recover(); err != nil {
+			err = errNotDefault
+		}
+	}()
+
+	mds, ok := dstore.(*mount.Datastore)
+	if !ok {
+		return "", nil, errNotDefault
+	}
+
+	mnts, ok := getUnexportedField(reflect.ValueOf(mds).Elem().FieldByName("mounts")).([]mount.Mount)
+	if !ok {
+		return "", nil, errNotDefault
+	}
+
+	if len(mnts) != 2 {
+		return "", nil, errNotDefault
+	}
+
+	var blkDs ds.Datastore
+	if mnts[0].Prefix.Equal(blocksPrefix) {
+		blkDs = mnts[0].Datastore
+	} else if mnts[1].Prefix.Equal(blocksPrefix) {
+		blkDs = mnts[1].Datastore
+	} else {
+		return "", nil, errNotDefault
+	}
+
+	if reflect.TypeOf(blkDs).String() != "*measure.measure" {
+		return "", nil, errNotDefault
+	}
+
+	fsds, ok := getUnexportedField(reflect.ValueOf(blkDs).Elem().FieldByName("backend")).(*flatfs.Datastore)
+	if !ok {
+		return "", nil, errNotDefault
+	}
+	fsdsPath := reflect.ValueOf(fsds).Elem().FieldByName("path").String()
+
+	shard, err := flatfs.ParseShardFunc(fsds.ShardStr())
+	if err != nil {
+		return "", nil, errNotDefault
+	}
+	return fsdsPath, shard, nil
+}
+
 // Create a file to store the list of migrated CIDs. If it exists, it is
 // opened for appending only.
 func createBackupFile(path, name string) (*os.File, error) {

fs-repo-11-to-12/migration/swapper.go

@@ -2,14 +2,17 @@ package mg11
 
 import (
 	"errors"
+	flatfs "github.com/ipfs/go-ds-flatfs"
 	"os"
+	"path/filepath"
 	"strconv"
 	"sync"
 	"sync/atomic"
 
 	log "github.com/ipfs/fs-repo-migrations/tools/stump"
 	cid "github.com/ipfs/go-cid"
 	ds "github.com/ipfs/go-datastore"
+	ktds "github.com/ipfs/go-datastore/keytransform"
 	query "github.com/ipfs/go-datastore/query"
 	dshelp "github.com/ipfs/go-ipfs-ds-help"
 )
@@ -177,10 +180,71 @@ func (cswap *CidSwapper) prepareWorker(resultsCh <-chan query.Result) (uint64, u
 	return sw.swapped, errored
 }
 
+func (cswap *CidSwapper) swapWorkerFlatFS(fsdsPath string, fsdsShard *flatfs.ShardIdV1, swapCh <-chan Swap, reverting bool) (uint64, uint64) {
+	var swapped, errored uint64
+
+	const flatfsExtension = ".data"
+	prefix := ktds.PrefixTransform{Prefix: blocksPrefix}
+
+	getPath := func(basePath string, key ds.Key) (string, string) {
+		child := prefix.InvertKey(key)
+		noslash := child.String()[1:]
+		dir := filepath.Join(fsdsPath, fsdsShard.Func()(noslash))
+		file := filepath.Join(dir, noslash+flatfsExtension)
+
+		return dir, file
+	}
+
+	// Process keys from the results channel
+	for sw := range swapCh {
+		if reverting {
+			old := sw.Old
+			sw.Old = sw.New
+			sw.New = old
+		}
+
+		_, oldPath := getPath(fsdsPath, sw.Old)
+		newDir, newPath := getPath(fsdsPath, sw.New)
+
+		_, err := os.Stat(oldPath)
+		if err != nil {
+			log.Error("could not swap %s->%s. Could not find %s even though it was in the backup file %s. Skipping.", sw.Old, sw.New, sw.Old, err.Error())
+			continue
+		}
+
+		if err := os.Mkdir(newDir, 0755); err != nil && !os.IsExist(err) {
+			log.Error("could not swap %s->%s. Skipping.", sw.Old, sw.New, err.Error())
+			continue
+		}
+
+		if err := os.Rename(oldPath, newPath); err != nil {
+			log.Error("could not swap %s->%s. Skipping.", sw.Old, sw.New, err.Error())
+			errored++
+			continue
+		}
+		swapped++
+
+		if cswap.SwapCh != nil {
+			cswap.SwapCh <- Swap{Old: sw.Old, New: sw.New}
+		}
+	}
+
+	return swapped, errored
+}
+
 // unswap worker takes notifications from unswapCh (as they would be sent by
 // the swapWorker) and undoes them. It ignores NotFound errors so that reverts
 // can succeed even if they failed half-way.
 func (cswap *CidSwapper) swapWorker(swapCh <-chan Swap, reverting bool) (uint64, uint64) {
+	fsdsPath, fsDsShard, err := IsDefaultConfig(cswap.Store)
+	if err != nil {
+		return cswap.swapWorkerDS(swapCh, reverting)
+	}
+
+	return cswap.swapWorkerFlatFS(fsdsPath, fsDsShard, swapCh, reverting)
+}
+
+func (cswap *CidSwapper) swapWorkerDS(swapCh <-chan Swap, reverting bool) (uint64, uint64) {
 	var errored uint64
 
 	swker := &swapWorker{

fs-repo-11-to-12/vendor/modules.txt

@@ -127,6 +127,7 @@ github.com/ipfs/go-datastore/sync
 ## explicit
 github.com/ipfs/go-ds-badger
 # github.com/ipfs/go-ds-flatfs v0.4.5
+## explicit
 github.com/ipfs/go-ds-flatfs
 # github.com/ipfs/go-ds-leveldb v0.4.2
 github.com/ipfs/go-ds-leveldb