syncthing/lib/db/meta.go
Jakob Borg 7a92f6c6b1
lib/db: Don't panic on negative counts (#4761)
* lib/db: Don't panic on negative counts (fixes #4659)

So, negative counts should never happen and hence the original idea to
panic. However, this sucks as the panic will happen in a folder runner,
be automatically swallowed by suture, and the runner gets restarted but
now we are in a bad state. (Related: #4758)

At the time of writing the global list is somewhat in flux (we've
changed how ignored files are handled, invalid bits, etc.) and I think
that can cause unusual conditions here. Hence just fixing up the numbers
instead until the next full recount.
2018-02-14 11:25:34 +01:00

237 lines
5.5 KiB
Go

// Copyright (C) 2017 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 https://mozilla.org/MPL/2.0/.
package db
import (
"time"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/sync"
)
// like protocol.LocalDeviceID but with 0xf8 in all positions
var globalDeviceID = protocol.DeviceID{0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8, 0xf8}
type metadataTracker struct {
mut sync.RWMutex
counts CountsSet
indexes map[protocol.DeviceID]int // device ID -> index in counts
}
func newMetadataTracker() *metadataTracker {
return &metadataTracker{
mut: sync.NewRWMutex(),
indexes: make(map[protocol.DeviceID]int),
}
}
// Unmarshal loads a metadataTracker from the corresponding protobuf
// representation
func (m *metadataTracker) Unmarshal(bs []byte) error {
if err := m.counts.Unmarshal(bs); err != nil {
return err
}
// Initialize the index map
for i, c := range m.counts.Counts {
m.indexes[protocol.DeviceIDFromBytes(c.DeviceID)] = i
}
return nil
}
// Unmarshal returns the protobuf representation of the metadataTracker
func (m *metadataTracker) Marshal() ([]byte, error) {
return m.counts.Marshal()
}
// toDB saves the marshalled metadataTracker to the given db, under the key
// corresponding to the given folder
func (m *metadataTracker) toDB(db *Instance, folder []byte) error {
key := db.folderMetaKey(folder)
bs, err := m.Marshal()
if err != nil {
return err
}
return db.Put(key, bs, nil)
}
// fromDB initializes the metadataTracker from the marshalled data found in
// the database under the key corresponding to the given folder
func (m *metadataTracker) fromDB(db *Instance, folder []byte) error {
key := db.folderMetaKey(folder)
bs, err := db.Get(key, nil)
if err != nil {
return err
}
return m.Unmarshal(bs)
}
// countsPtr returns a pointer to the corresponding Counts struct, if
// necessary allocating one in the process
func (m *metadataTracker) countsPtr(dev protocol.DeviceID) *Counts {
// must be called with the mutex held
idx, ok := m.indexes[dev]
if !ok {
idx = len(m.counts.Counts)
m.counts.Counts = append(m.counts.Counts, Counts{DeviceID: dev[:]})
m.indexes[dev] = idx
}
return &m.counts.Counts[idx]
}
// addFile adds a file to the counts, adjusting the sequence number as
// appropriate
func (m *metadataTracker) addFile(dev protocol.DeviceID, f FileIntf) {
if f.IsInvalid() {
return
}
m.mut.Lock()
cp := m.countsPtr(dev)
switch {
case f.IsDeleted():
cp.Deleted++
case f.IsDirectory() && !f.IsSymlink():
cp.Directories++
case f.IsSymlink():
cp.Symlinks++
default:
cp.Files++
}
cp.Bytes += f.FileSize()
if seq := f.SequenceNo(); seq > cp.Sequence {
cp.Sequence = seq
}
m.mut.Unlock()
}
// removeFile removes a file from the counts
func (m *metadataTracker) removeFile(dev protocol.DeviceID, f FileIntf) {
if f.IsInvalid() {
return
}
m.mut.Lock()
cp := m.countsPtr(dev)
switch {
case f.IsDeleted():
cp.Deleted--
case f.IsDirectory() && !f.IsSymlink():
cp.Directories--
case f.IsSymlink():
cp.Symlinks--
default:
cp.Files--
}
cp.Bytes -= f.FileSize()
// If we've run into an impossible situation, correct it for now and set
// the created timestamp to zero. Next time we start up the metadata
// will be seen as infinitely old and recalculated from scratch.
if cp.Deleted < 0 {
cp.Deleted = 0
m.counts.Created = 0
}
if cp.Files < 0 {
cp.Files = 0
m.counts.Created = 0
}
if cp.Directories < 0 {
cp.Directories = 0
m.counts.Created = 0
}
if cp.Symlinks < 0 {
cp.Symlinks = 0
m.counts.Created = 0
}
m.mut.Unlock()
}
// resetAll resets all metadata for the given device
func (m *metadataTracker) resetAll(dev protocol.DeviceID) {
m.mut.Lock()
*m.countsPtr(dev) = Counts{DeviceID: dev[:]}
m.mut.Unlock()
}
// resetCounts resets the file, dir, etc. counters, while retaining the
// sequence number
func (m *metadataTracker) resetCounts(dev protocol.DeviceID) {
m.mut.Lock()
c := m.countsPtr(dev)
c.Bytes = 0
c.Deleted = 0
c.Directories = 0
c.Files = 0
c.Symlinks = 0
// c.Sequence deliberately untouched
m.mut.Unlock()
}
// Counts returns the counts for the given device ID
func (m *metadataTracker) Counts(dev protocol.DeviceID) Counts {
m.mut.RLock()
defer m.mut.RUnlock()
idx, ok := m.indexes[dev]
if !ok {
return Counts{}
}
return m.counts.Counts[idx]
}
// nextSeq allocates a new sequence number for the given device
func (m *metadataTracker) nextSeq(dev protocol.DeviceID) int64 {
m.mut.Lock()
defer m.mut.Unlock()
c := m.countsPtr(dev)
c.Sequence++
return c.Sequence
}
// devices returns the list of devices tracked, excluding the local device
// (which we don't know the ID of)
func (m *metadataTracker) devices() []protocol.DeviceID {
devs := make([]protocol.DeviceID, 0, len(m.counts.Counts))
m.mut.RLock()
for _, dev := range m.counts.Counts {
if dev.Sequence > 0 {
id := protocol.DeviceIDFromBytes(dev.DeviceID)
if id == globalDeviceID || id == protocol.LocalDeviceID {
continue
}
devs = append(devs, id)
}
}
m.mut.RUnlock()
return devs
}
func (m *metadataTracker) Created() time.Time {
m.mut.RLock()
defer m.mut.RUnlock()
return time.Unix(0, m.counts.Created)
}
func (m *metadataTracker) SetCreated() {
m.mut.Lock()
m.counts.Created = time.Now().UnixNano()
m.mut.Unlock()
}