lib/db: Consistent use of buffers (#5470)

lib/db/instance.go

@@ -34,7 +34,7 @@ func (db *instance) updateFiles(folder, device []byte, fs []protocol.FileInfo, m
 	t := db.newReadWriteTransaction()
 	defer t.close()
 
-	var dk, gk []byte
+	var dk, gk, keyBuf []byte
 	devID := protocol.DeviceIDFromBytes(device)
 	for _, f := range fs {
 		name := []byte(f.Name)
@@ -53,7 +53,7 @@ func (db *instance) updateFiles(folder, device []byte, fs []protocol.FileInfo, m
 		t.insertFile(dk, folder, device, f)
 
 		gk = db.keyer.GenerateGlobalVersionKey(gk, folder, name)
-		t.updateGlobal(gk, folder, device, f, meta)
+		keyBuf, _ = t.updateGlobal(gk, keyBuf, folder, device, f, meta)
 
 		// Write out and reuse the batch every few records, to avoid the batch
 		// growing too large and thus allocating unnecessarily much memory.
@@ -156,7 +156,7 @@ func (db *instance) withAllFolderTruncated(folder []byte, fn func(device []byte,
 	dbi := t.NewIterator(util.BytesPrefix(db.keyer.GenerateDeviceFileKey(nil, folder, nil, nil).WithoutNameAndDevice()), nil)
 	defer dbi.Release()
 
-	var gk []byte
+	var gk, buf []byte
 	for dbi.Next() {
 		device, ok := db.keyer.DeviceFromDeviceFileKey(dbi.Key())
 		if !ok {
@@ -181,7 +181,7 @@ func (db *instance) withAllFolderTruncated(folder []byte, fn func(device []byte,
 			l.Infof("Dropping invalid filename %q from database", f.Name)
 			name := []byte(f.Name)
 			gk = db.keyer.GenerateGlobalVersionKey(gk, folder, name)
-			t.removeFromGlobal(gk, folder, device, name, nil)
+			buf = t.removeFromGlobal(gk, buf, folder, device, name, nil)
 			t.Delete(dbi.Key())
 			t.checkFlush()
 			continue
@@ -202,8 +202,7 @@ func (db *instance) getFileDirty(folder, device, file []byte) (protocol.FileInfo
 func (db *instance) getGlobalDirty(folder, file []byte, truncate bool) (FileIntf, bool) {
 	t := db.newReadOnlyTransaction()
 	defer t.close()
-
-	_, _, f, ok := t.getGlobalInto(nil, nil, folder, file, truncate)
+	_, f, ok := t.getGlobal(nil, folder, file, truncate)
 	return f, ok
 }
 
@@ -219,7 +218,7 @@ func (db *instance) withGlobal(folder, prefix []byte, truncate bool, fn Iterator
 			prefix = append(prefix, '/')
 		}
 
-		if _, _, f, ok := t.getGlobalInto(nil, nil, folder, unslashedPrefix, truncate); ok && !fn(f) {
+		if _, f, ok := t.getGlobal(nil, folder, unslashedPrefix, truncate); ok && !fn(f) {
 			return
 		}
 	}
@@ -363,11 +362,11 @@ func (db *instance) withNeedLocal(folder []byte, truncate bool, fn Iterator) {
 	dbi := t.NewIterator(util.BytesPrefix(db.keyer.GenerateNeedFileKey(nil, folder, nil).WithoutName()), nil)
 	defer dbi.Release()
 
-	var gk, dk []byte
+	var buf []byte
 	var f FileIntf
 	var ok bool
 	for dbi.Next() {
-		gk, dk, f, ok = t.getGlobalInto(gk, dk, folder, db.keyer.NameFromGlobalVersionKey(dbi.Key()), truncate)
+		buf, f, ok = t.getGlobal(buf, folder, db.keyer.NameFromGlobalVersionKey(dbi.Key()), truncate)
 		if !ok {
 			continue
 		}
@@ -402,13 +401,12 @@ func (db *instance) dropDeviceFolder(device, folder []byte, meta *metadataTracke
 	dbi := t.NewIterator(util.BytesPrefix(db.keyer.GenerateDeviceFileKey(nil, folder, device, nil)), nil)
 	defer dbi.Release()
 
-	var gk []byte
+	var gk, buf []byte
 	for dbi.Next() {
-		key := dbi.Key()
-		name := db.keyer.NameFromDeviceFileKey(key)
+		name := db.keyer.NameFromDeviceFileKey(dbi.Key())
 		gk = db.keyer.GenerateGlobalVersionKey(gk, folder, name)
-		t.removeFromGlobal(gk, folder, device, name, meta)
-		t.Delete(key)
+		buf = t.removeFromGlobal(gk, buf, folder, device, name, meta)
+		t.Delete(dbi.Key())
 		t.checkFlush()
 	}
 }

lib/db/schemaupdater.go

@@ -101,7 +101,7 @@ func (db *schemaUpdater) updateSchema0to1() {
 	changedFolders := make(map[string]struct{})
 	ignAdded := 0
 	meta := newMetadataTracker() // dummy metadata tracker
-	var gk []byte
+	var gk, buf []byte
 
 	for dbi.Next() {
 		folder, ok := db.keyer.FolderFromDeviceFileKey(dbi.Key())
@@ -126,7 +126,7 @@ func (db *schemaUpdater) updateSchema0to1() {
 				changedFolders[string(folder)] = struct{}{}
 			}
 			gk = db.keyer.GenerateGlobalVersionKey(gk, folder, name)
-			t.removeFromGlobal(gk, folder, device, nil, nil)
+			buf = t.removeFromGlobal(gk, buf, folder, device, nil, nil)
 			t.Delete(dbi.Key())
 			t.checkFlush()
 			continue
@@ -156,8 +156,8 @@ func (db *schemaUpdater) updateSchema0to1() {
 		// Add invalid files to global list
 		if f.IsInvalid() {
 			gk = db.keyer.GenerateGlobalVersionKey(gk, folder, name)
-			if t.updateGlobal(gk, folder, device, f, meta) {
-				if _, ok := changedFolders[string(folder)]; !ok {
+			if buf, ok = t.updateGlobal(gk, buf, folder, device, f, meta); ok {
+				if _, ok = changedFolders[string(folder)]; !ok {
 					changedFolders[string(folder)] = struct{}{}
 				}
 				ignAdded++

lib/db/transactions.go

@@ -56,7 +56,6 @@ func (t readOnlyTransaction) getFileTrunc(key []byte, trunc bool) (FileIntf, boo
 		l.Debugln("surprise error:", err)
 		return nil, false
 	}
-
 	f, err := unmarshalTrunc(bs, trunc)
 	if err != nil {
 		l.Debugln("unmarshal error:", err)
@@ -65,25 +64,25 @@ func (t readOnlyTransaction) getFileTrunc(key []byte, trunc bool) (FileIntf, boo
 	return f, true
 }
 
-func (t readOnlyTransaction) getGlobalInto(gk, dk, folder, file []byte, truncate bool) ([]byte, []byte, FileIntf, bool) {
-	gk = t.db.keyer.GenerateGlobalVersionKey(gk, folder, file)
+func (t readOnlyTransaction) getGlobal(keyBuf, folder, file []byte, truncate bool) ([]byte, FileIntf, bool) {
+	keyBuf = t.db.keyer.GenerateGlobalVersionKey(keyBuf, folder, file)
 
-	bs, err := t.Get(gk, nil)
+	bs, err := t.Get(keyBuf, nil)
 	if err != nil {
-		return gk, dk, nil, false
+		return keyBuf, nil, false
 	}
 
 	vl, ok := unmarshalVersionList(bs)
 	if !ok {
-		return gk, dk, nil, false
+		return keyBuf, nil, false
 	}
 
-	dk = t.db.keyer.GenerateDeviceFileKey(dk, folder, vl.Versions[0].Device, file)
-	if fi, ok := t.getFileTrunc(dk, truncate); ok {
-		return gk, dk, fi, true
+	keyBuf = t.db.keyer.GenerateDeviceFileKey(keyBuf, folder, vl.Versions[0].Device, file)
+	if fi, ok := t.getFileTrunc(keyBuf, truncate); ok {
+		return keyBuf, fi, true
 	}
 
-	return gk, dk, nil, false
+	return keyBuf, nil, false
 }
 
 // A readWriteTransaction is a readOnlyTransaction plus a batch for writes.
@@ -129,7 +128,7 @@ func (t readWriteTransaction) insertFile(fk, folder, device []byte, file protoco
 // updateGlobal adds this device+version to the version list for the given
 // file. If the device is already present in the list, the version is updated.
 // If the file does not have an entry in the global list, it is created.
-func (t readWriteTransaction) updateGlobal(gk, folder, device []byte, file protocol.FileInfo, meta *metadataTracker) bool {
+func (t readWriteTransaction) updateGlobal(gk, keyBuf, folder, device []byte, file protocol.FileInfo, meta *metadataTracker) ([]byte, bool) {
 	l.Debugf("update global; folder=%q device=%v file=%q version=%v invalid=%v", folder, protocol.DeviceIDFromBytes(device), file.Name, file.Version, file.IsInvalid())
 
 	var fl VersionList
@@ -139,7 +138,7 @@ func (t readWriteTransaction) updateGlobal(gk, folder, device []byte, file proto
 	fl, removedFV, removedAt, insertedAt := fl.update(folder, device, file, t.readOnlyTransaction)
 	if insertedAt == -1 {
 		l.Debugln("update global; same version, global unchanged")
-		return false
+		return keyBuf, false
 	}
 
 	name := []byte(file.Name)
@@ -148,19 +147,22 @@ func (t readWriteTransaction) updateGlobal(gk, folder, device []byte, file proto
 	if insertedAt == 0 {
 		// Inserted a new newest version
 		global = file
-	} else if new, ok := t.getFile(folder, fl.Versions[0].Device, name); ok {
-		global = new
 	} else {
-		panic("This file must exist in the db")
+		keyBuf = t.db.keyer.GenerateDeviceFileKey(keyBuf, folder, fl.Versions[0].Device, name)
+		if new, ok := t.getFileByKey(keyBuf); ok {
+			global = new
+		} else {
+			panic("This file must exist in the db")
+		}
 	}
 
 	// Fixup the list of files we need.
-	t.updateLocalNeed(folder, name, fl, global)
+	keyBuf = t.updateLocalNeed(keyBuf, folder, name, fl, global)
 
 	if removedAt != 0 && insertedAt != 0 {
 		l.Debugf(`new global for "%v" after update: %v`, file.Name, fl)
 		t.Put(gk, mustMarshal(&fl))
-		return true
+		return keyBuf, true
 	}
 
 	// Remove the old global from the global size counter
@@ -171,7 +173,8 @@ func (t readWriteTransaction) updateGlobal(gk, folder, device []byte, file proto
 		// The previous newest version is now at index 1
 		oldGlobalFV = fl.Versions[1]
 	}
-	if oldFile, ok := t.getFile(folder, oldGlobalFV.Device, name); ok {
+	keyBuf = t.db.keyer.GenerateDeviceFileKey(keyBuf, folder, oldGlobalFV.Device, name)
+	if oldFile, ok := t.getFileByKey(keyBuf); ok {
 		// A failure to get the file here is surprising and our
 		// global size data will be incorrect until a restart...
 		meta.removeFile(protocol.GlobalDeviceID, oldFile)
@@ -183,24 +186,25 @@ func (t readWriteTransaction) updateGlobal(gk, folder, device []byte, file proto
 	l.Debugf(`new global for "%v" after update: %v`, file.Name, fl)
 	t.Put(gk, mustMarshal(&fl))
 
-	return true
+	return keyBuf, true
 }
 
-// updateLocalNeeds checks whether the given file is still needed on the local
+// updateLocalNeed checks whether the given file is still needed on the local
 // device according to the version list and global FileInfo given and updates
 // the db accordingly.
-func (t readWriteTransaction) updateLocalNeed(folder, name []byte, fl VersionList, global protocol.FileInfo) {
-	nk := t.db.keyer.GenerateNeedFileKey(nil, folder, name)
-	hasNeeded, _ := t.db.Has(nk, nil)
+func (t readWriteTransaction) updateLocalNeed(keyBuf, folder, name []byte, fl VersionList, global protocol.FileInfo) []byte {
+	keyBuf = t.db.keyer.GenerateNeedFileKey(keyBuf, folder, name)
+	hasNeeded, _ := t.Has(keyBuf, nil)
 	if localFV, haveLocalFV := fl.Get(protocol.LocalDeviceID[:]); need(global, haveLocalFV, localFV.Version) {
 		if !hasNeeded {
 			l.Debugf("local need insert; folder=%q, name=%q", folder, name)
-			t.Put(nk, nil)
+			t.Put(keyBuf, nil)
 		}
 	} else if hasNeeded {
 		l.Debugf("local need delete; folder=%q, name=%q", folder, name)
-		t.Delete(nk)
+		t.Delete(keyBuf)
 	}
+	return keyBuf
 }
 
 func need(global FileIntf, haveLocal bool, localVersion protocol.Vector) bool {
@@ -222,54 +226,59 @@ func need(global FileIntf, haveLocal bool, localVersion protocol.Vector) bool {
 // removeFromGlobal removes the device from the global version list for the
 // given file. If the version list is empty after this, the file entry is
 // removed entirely.
-func (t readWriteTransaction) removeFromGlobal(gk, folder, device, file []byte, meta *metadataTracker) {
+func (t readWriteTransaction) removeFromGlobal(gk, keyBuf, folder, device []byte, file []byte, meta *metadataTracker) []byte {
 	l.Debugf("remove from global; folder=%q device=%v file=%q", folder, protocol.DeviceIDFromBytes(device), file)
 
 	svl, err := t.Get(gk, nil)
 	if err != nil {
 		// We might be called to "remove" a global version that doesn't exist
 		// if the first update for the file is already marked invalid.
-		return
+		return keyBuf
 	}
 
 	var fl VersionList
 	err = fl.Unmarshal(svl)
 	if err != nil {
 		l.Debugln("unmarshal error:", err)
-		return
+		return keyBuf
 	}
 
 	fl, _, removedAt := fl.pop(device)
 	if removedAt == -1 {
 		// There is no version for the given device
-		return
+		return keyBuf
 	}
 
 	if removedAt == 0 {
 		// A failure to get the file here is surprising and our
 		// global size data will be incorrect until a restart...
-		if f, ok := t.getFile(folder, device, file); ok {
+		keyBuf = t.db.keyer.GenerateDeviceFileKey(keyBuf, folder, device, file)
+		if f, ok := t.getFileByKey(keyBuf); ok {
 			meta.removeFile(protocol.GlobalDeviceID, f)
 		}
 	}
 
 	if len(fl.Versions) == 0 {
-		t.Delete(t.db.keyer.GenerateNeedFileKey(nil, folder, file))
+		keyBuf = t.db.keyer.GenerateNeedFileKey(keyBuf, folder, file)
+		t.Delete(keyBuf)
 		t.Delete(gk)
-		return
+		return keyBuf
 	}
 
 	if removedAt == 0 {
-		global, ok := t.getFile(folder, fl.Versions[0].Device, file)
+		keyBuf = t.db.keyer.GenerateDeviceFileKey(keyBuf, folder, fl.Versions[0].Device, file)
+		global, ok := t.getFileByKey(keyBuf)
 		if !ok {
 			panic("This file must exist in the db")
 		}
-		t.updateLocalNeed(folder, file, fl, global)
+		keyBuf = t.updateLocalNeed(keyBuf, folder, file, fl, global)
 		meta.addFile(protocol.GlobalDeviceID, global)
 	}
 
 	l.Debugf("new global after remove: %v", fl)
 	t.Put(gk, mustMarshal(&fl))
+
+	return keyBuf
 }
 
 func (t readWriteTransaction) deleteKeyPrefix(prefix []byte) {