syncthing/lib/db/leveldb_dbinstance.go

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// Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
package db
import (
"bytes"
"os"
"sort"
"strings"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/errors"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/storage"
"github.com/syndtr/goleveldb/leveldb/util"
)
type deletionHandler func(t readWriteTransaction, folder, device, name []byte, dbi iterator.Iterator) int64
type Instance struct {
*leveldb.DB
}
func Open(file string) (*Instance, error) {
opts := &opt.Options{
OpenFilesCacheCapacity: 100,
WriteBuffer: 4 << 20,
}
db, err := leveldb.OpenFile(file, opts)
if leveldbIsCorrupted(err) {
db, err = leveldb.RecoverFile(file, opts)
}
if leveldbIsCorrupted(err) {
// The database is corrupted, and we've tried to recover it but it
// didn't work. At this point there isn't much to do beyond dropping
// the database and reindexing...
l.Infoln("Database corruption detected, unable to recover. Reinitializing...")
if err := os.RemoveAll(file); err != nil {
return nil, err
}
db, err = leveldb.OpenFile(file, opts)
}
if err != nil {
return nil, err
}
return newDBInstance(db), nil
}
func OpenMemory() *Instance {
db, _ := leveldb.Open(storage.NewMemStorage(), nil)
return newDBInstance(db)
}
func newDBInstance(db *leveldb.DB) *Instance {
return &Instance{
DB: db,
}
}
func (db *Instance) genericReplace(folder, device []byte, fs []protocol.FileInfo, localSize, globalSize *sizeTracker, deleteFn deletionHandler) int64 {
sort.Sort(fileList(fs)) // sort list on name, same as in the database
start := db.deviceKey(folder, device, nil) // before all folder/device files
limit := db.deviceKey(folder, device, []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
t := db.newReadWriteTransaction()
defer t.close()
dbi := t.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
moreDb := dbi.Next()
fsi := 0
var maxLocalVer int64
isLocalDevice := bytes.Equal(device, protocol.LocalDeviceID[:])
for {
var newName, oldName []byte
moreFs := fsi < len(fs)
if !moreDb && !moreFs {
break
}
if moreFs {
newName = []byte(fs[fsi].Name)
}
if moreDb {
oldName = db.deviceKeyName(dbi.Key())
}
cmp := bytes.Compare(newName, oldName)
l.Debugf("generic replace; folder=%q device=%v moreFs=%v moreDb=%v cmp=%d newName=%q oldName=%q", folder, protocol.DeviceIDFromBytes(device), moreFs, moreDb, cmp, newName, oldName)
switch {
case moreFs && (!moreDb || cmp == -1):
l.Debugln("generic replace; missing - insert")
// Database is missing this file. Insert it.
if lv := t.insertFile(folder, device, fs[fsi]); lv > maxLocalVer {
maxLocalVer = lv
}
if isLocalDevice {
localSize.addFile(fs[fsi])
}
if fs[fsi].IsInvalid() {
t.removeFromGlobal(folder, device, newName, globalSize)
} else {
t.updateGlobal(folder, device, fs[fsi], globalSize)
}
fsi++
case moreFs && moreDb && cmp == 0:
// File exists on both sides - compare versions. We might get an
// update with the same version and different flags if a device has
// marked a file as invalid, so handle that too.
l.Debugln("generic replace; exists - compare")
var ef FileInfoTruncated
ef.UnmarshalXDR(dbi.Value())
if !fs[fsi].Version.Equal(ef.Version) || fs[fsi].Flags != ef.Flags {
l.Debugln("generic replace; differs - insert")
if lv := t.insertFile(folder, device, fs[fsi]); lv > maxLocalVer {
maxLocalVer = lv
}
if isLocalDevice {
localSize.removeFile(ef)
localSize.addFile(fs[fsi])
}
if fs[fsi].IsInvalid() {
t.removeFromGlobal(folder, device, newName, globalSize)
} else {
t.updateGlobal(folder, device, fs[fsi], globalSize)
}
} else {
l.Debugln("generic replace; equal - ignore")
}
fsi++
moreDb = dbi.Next()
case moreDb && (!moreFs || cmp == 1):
l.Debugln("generic replace; exists - remove")
if lv := deleteFn(t, folder, device, oldName, dbi); lv > maxLocalVer {
maxLocalVer = lv
}
moreDb = dbi.Next()
}
// Write out and reuse the batch every few records, to avoid the batch
// growing too large and thus allocating unnecessarily much memory.
t.checkFlush()
}
return maxLocalVer
}
func (db *Instance) replace(folder, device []byte, fs []protocol.FileInfo, localSize, globalSize *sizeTracker) int64 {
// TODO: Return the remaining maxLocalVer?
return db.genericReplace(folder, device, fs, localSize, globalSize, func(t readWriteTransaction, folder, device, name []byte, dbi iterator.Iterator) int64 {
// Database has a file that we are missing. Remove it.
l.Debugf("delete; folder=%q device=%v name=%q", folder, protocol.DeviceIDFromBytes(device), name)
t.removeFromGlobal(folder, device, name, globalSize)
t.Delete(dbi.Key())
return 0
})
}
func (db *Instance) updateFiles(folder, device []byte, fs []protocol.FileInfo, localSize, globalSize *sizeTracker) int64 {
t := db.newReadWriteTransaction()
defer t.close()
var maxLocalVer int64
var fk []byte
isLocalDevice := bytes.Equal(device, protocol.LocalDeviceID[:])
for _, f := range fs {
name := []byte(f.Name)
fk = db.deviceKeyInto(fk[:cap(fk)], folder, device, name)
bs, err := t.Get(fk, nil)
if err == leveldb.ErrNotFound {
if isLocalDevice {
localSize.addFile(f)
}
if lv := t.insertFile(folder, device, f); lv > maxLocalVer {
maxLocalVer = lv
}
if f.IsInvalid() {
t.removeFromGlobal(folder, device, name, globalSize)
} else {
t.updateGlobal(folder, device, f, globalSize)
}
continue
}
var ef FileInfoTruncated
err = ef.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
// Flags might change without the version being bumped when we set the
// invalid flag on an existing file.
if !ef.Version.Equal(f.Version) || ef.Flags != f.Flags {
if isLocalDevice {
localSize.removeFile(ef)
localSize.addFile(f)
}
if lv := t.insertFile(folder, device, f); lv > maxLocalVer {
maxLocalVer = lv
}
if f.IsInvalid() {
t.removeFromGlobal(folder, device, name, globalSize)
} else {
t.updateGlobal(folder, device, f, globalSize)
}
}
// Write out and reuse the batch every few records, to avoid the batch
// growing too large and thus allocating unnecessarily much memory.
t.checkFlush()
}
return maxLocalVer
}
func (db *Instance) withHave(folder, device []byte, truncate bool, fn Iterator) {
start := db.deviceKey(folder, device, nil) // before all folder/device files
limit := db.deviceKey(folder, device, []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
t := db.newReadOnlyTransaction()
defer t.close()
dbi := t.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
for dbi.Next() {
f, err := unmarshalTrunc(dbi.Value(), truncate)
if err != nil {
panic(err)
}
if cont := fn(f); !cont {
return
}
}
}
func (db *Instance) withAllFolderTruncated(folder []byte, fn func(device []byte, f FileInfoTruncated) bool) {
start := db.deviceKey(folder, nil, nil) // before all folder/device files
limit := db.deviceKey(folder, protocol.LocalDeviceID[:], []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
t := db.newReadWriteTransaction()
defer t.close()
dbi := t.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
for dbi.Next() {
device := db.deviceKeyDevice(dbi.Key())
var f FileInfoTruncated
err := f.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
switch f.Name {
case "", ".", "..", "/": // A few obviously invalid filenames
l.Infof("Dropping invalid filename %q from database", f.Name)
t.removeFromGlobal(folder, device, nil, nil)
t.Delete(dbi.Key())
t.checkFlush()
continue
}
if cont := fn(device, f); !cont {
return
}
}
}
func (db *Instance) getFile(folder, device, file []byte) (protocol.FileInfo, bool) {
return getFile(db, db.deviceKey(folder, device, file))
}
func (db *Instance) getGlobal(folder, file []byte, truncate bool) (FileIntf, bool) {
k := db.globalKey(folder, file)
t := db.newReadOnlyTransaction()
defer t.close()
bs, err := t.Get(k, nil)
if err == leveldb.ErrNotFound {
return nil, false
}
if err != nil {
panic(err)
}
var vl versionList
err = vl.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(k)
panic("no versions?")
}
k = db.deviceKey(folder, vl.versions[0].device, file)
bs, err = t.Get(k, nil)
if err != nil {
panic(err)
}
fi, err := unmarshalTrunc(bs, truncate)
if err != nil {
panic(err)
}
return fi, true
}
func (db *Instance) withGlobal(folder, prefix []byte, truncate bool, fn Iterator) {
t := db.newReadOnlyTransaction()
defer t.close()
dbi := t.NewIterator(util.BytesPrefix(db.globalKey(folder, prefix)), nil)
defer dbi.Release()
var fk []byte
for dbi.Next() {
var vl versionList
err := vl.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(dbi.Key())
panic("no versions?")
}
name := db.globalKeyName(dbi.Key())
fk = db.deviceKeyInto(fk[:cap(fk)], folder, vl.versions[0].device, name)
bs, err := t.Get(fk, nil)
if err != nil {
l.Debugf("folder: %q (%x)", folder, folder)
l.Debugf("key: %q (%x)", dbi.Key(), dbi.Key())
l.Debugf("vl: %v", vl)
l.Debugf("vl.versions[0].device: %x", vl.versions[0].device)
l.Debugf("name: %q (%x)", name, name)
l.Debugf("fk: %q", fk)
l.Debugf("fk: %x %x %x", fk[1:1+64], fk[1+64:1+64+32], fk[1+64+32:])
panic(err)
}
f, err := unmarshalTrunc(bs, truncate)
if err != nil {
panic(err)
}
if cont := fn(f); !cont {
return
}
}
}
func (db *Instance) availability(folder, file []byte) []protocol.DeviceID {
k := db.globalKey(folder, file)
bs, err := db.Get(k, nil)
if err == leveldb.ErrNotFound {
return nil
}
if err != nil {
panic(err)
}
var vl versionList
err = vl.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
var devices []protocol.DeviceID
for _, v := range vl.versions {
if !v.version.Equal(vl.versions[0].version) {
break
}
n := protocol.DeviceIDFromBytes(v.device)
devices = append(devices, n)
}
return devices
}
func (db *Instance) withNeed(folder, device []byte, truncate bool, fn Iterator) {
start := db.globalKey(folder, nil)
limit := db.globalKey(folder, []byte{0xff, 0xff, 0xff, 0xff})
t := db.newReadOnlyTransaction()
defer t.close()
dbi := t.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
var fk []byte
nextFile:
for dbi.Next() {
var vl versionList
err := vl.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(dbi.Key())
panic("no versions?")
}
have := false // If we have the file, any version
need := false // If we have a lower version of the file
var haveVersion protocol.Vector
for _, v := range vl.versions {
if bytes.Compare(v.device, device) == 0 {
have = true
haveVersion = v.version
// XXX: This marks Concurrent (i.e. conflicting) changes as
// needs. Maybe we should do that, but it needs special
// handling in the puller.
need = !v.version.GreaterEqual(vl.versions[0].version)
break
}
}
if need || !have {
name := db.globalKeyName(dbi.Key())
needVersion := vl.versions[0].version
nextVersion:
for i := range vl.versions {
if !vl.versions[i].version.Equal(needVersion) {
// We haven't found a valid copy of the file with the needed version.
continue nextFile
}
fk = db.deviceKeyInto(fk[:cap(fk)], folder, vl.versions[i].device, name)
bs, err := t.Get(fk, nil)
if err != nil {
var id protocol.DeviceID
copy(id[:], device)
l.Debugf("device: %v", id)
l.Debugf("need: %v, have: %v", need, have)
l.Debugf("key: %q (%x)", dbi.Key(), dbi.Key())
l.Debugf("vl: %v", vl)
l.Debugf("i: %v", i)
l.Debugf("fk: %q (%x)", fk, fk)
l.Debugf("name: %q (%x)", name, name)
panic(err)
}
gf, err := unmarshalTrunc(bs, truncate)
if err != nil {
panic(err)
}
if gf.IsInvalid() {
// The file is marked invalid for whatever reason, don't use it.
continue nextVersion
}
if gf.IsDeleted() && !have {
// We don't need deleted files that we don't have
continue nextFile
}
l.Debugf("need folder=%q device=%v name=%q need=%v have=%v haveV=%d globalV=%d", folder, protocol.DeviceIDFromBytes(device), name, need, have, haveVersion, vl.versions[0].version)
if cont := fn(gf); !cont {
return
}
// This file is handled, no need to look further in the version list
continue nextFile
}
}
}
}
func (db *Instance) ListFolders() []string {
t := db.newReadOnlyTransaction()
defer t.close()
dbi := t.NewIterator(util.BytesPrefix([]byte{KeyTypeGlobal}), nil)
defer dbi.Release()
folderExists := make(map[string]bool)
for dbi.Next() {
folder := string(db.globalKeyFolder(dbi.Key()))
if !folderExists[folder] {
folderExists[folder] = true
}
}
folders := make([]string, 0, len(folderExists))
for k := range folderExists {
folders = append(folders, k)
}
sort.Strings(folders)
return folders
}
func (db *Instance) dropFolder(folder []byte) {
t := db.newReadOnlyTransaction()
defer t.close()
// Remove all items related to the given folder from the device->file bucket
dbi := t.NewIterator(util.BytesPrefix([]byte{KeyTypeDevice}), nil)
for dbi.Next() {
itemFolder := db.deviceKeyFolder(dbi.Key())
if bytes.Compare(folder, itemFolder) == 0 {
db.Delete(dbi.Key(), nil)
}
}
dbi.Release()
// Remove all items related to the given folder from the global bucket
dbi = t.NewIterator(util.BytesPrefix([]byte{KeyTypeGlobal}), nil)
for dbi.Next() {
itemFolder := db.globalKeyFolder(dbi.Key())
if bytes.Compare(folder, itemFolder) == 0 {
db.Delete(dbi.Key(), nil)
}
}
dbi.Release()
}
func (db *Instance) checkGlobals(folder []byte, globalSize *sizeTracker) {
t := db.newReadWriteTransaction()
defer t.close()
start := db.globalKey(folder, nil)
limit := db.globalKey(folder, []byte{0xff, 0xff, 0xff, 0xff})
dbi := t.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
var fk []byte
for dbi.Next() {
gk := dbi.Key()
var vl versionList
err := vl.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
// Check the global version list for consistency. An issue in previous
// versions of goleveldb could result in reordered writes so that
// there are global entries pointing to no longer existing files. Here
// we find those and clear them out.
name := db.globalKeyName(gk)
var newVL versionList
for i, version := range vl.versions {
fk = db.deviceKeyInto(fk[:cap(fk)], folder, version.device, name)
_, err := t.Get(fk, nil)
if err == leveldb.ErrNotFound {
continue
}
if err != nil {
panic(err)
}
newVL.versions = append(newVL.versions, version)
if i == 0 {
fi, ok := t.getFile(folder, version.device, name)
if !ok {
panic("nonexistent global master file")
}
globalSize.addFile(fi)
}
}
if len(newVL.versions) != len(vl.versions) {
t.Put(dbi.Key(), newVL.MustMarshalXDR())
t.checkFlush()
}
}
l.Debugf("db check completed for %q", folder)
}
// deviceKey returns a byte slice encoding the following information:
// keyTypeDevice (1 byte)
// folder (64 bytes)
// device (32 bytes)
// name (variable size)
func (db *Instance) deviceKey(folder, device, file []byte) []byte {
return db.deviceKeyInto(nil, folder, device, file)
}
func (db *Instance) deviceKeyInto(k []byte, folder, device, file []byte) []byte {
reqLen := 1 + 64 + 32 + len(file)
if len(k) < reqLen {
k = make([]byte, reqLen)
}
k[0] = KeyTypeDevice
if len(folder) > 64 {
panic("folder name too long")
}
copy(k[1:], []byte(folder))
copy(k[1+64:], device[:])
copy(k[1+64+32:], []byte(file))
return k[:reqLen]
}
func (db *Instance) deviceKeyName(key []byte) []byte {
return key[1+64+32:]
}
func (db *Instance) deviceKeyFolder(key []byte) []byte {
folder := key[1 : 1+64]
izero := bytes.IndexByte(folder, 0)
if izero < 0 {
return folder
}
return folder[:izero]
}
func (db *Instance) deviceKeyDevice(key []byte) []byte {
return key[1+64 : 1+64+32]
}
// globalKey returns a byte slice encoding the following information:
// keyTypeGlobal (1 byte)
// folder (64 bytes)
// name (variable size)
func (db *Instance) globalKey(folder, file []byte) []byte {
k := make([]byte, 1+64+len(file))
k[0] = KeyTypeGlobal
if len(folder) > 64 {
panic("folder name too long")
}
copy(k[1:], []byte(folder))
copy(k[1+64:], []byte(file))
return k
}
func (db *Instance) globalKeyName(key []byte) []byte {
return key[1+64:]
}
func (db *Instance) globalKeyFolder(key []byte) []byte {
folder := key[1 : 1+64]
izero := bytes.IndexByte(folder, 0)
if izero < 0 {
return folder
}
return folder[:izero]
}
func unmarshalTrunc(bs []byte, truncate bool) (FileIntf, error) {
if truncate {
var tf FileInfoTruncated
err := tf.UnmarshalXDR(bs)
return tf, err
}
var tf protocol.FileInfo
err := tf.UnmarshalXDR(bs)
return tf, err
}
// A "better" version of leveldb's errors.IsCorrupted.
func leveldbIsCorrupted(err error) bool {
switch {
case err == nil:
return false
case errors.IsCorrupted(err):
return true
case strings.Contains(err.Error(), "corrupted"):
return true
}
return false
}