syncthing/lib/model/folder.go
Simon Frei 158859a1e2 lib: Handle metadata changes for send-only folders (fixes #4616, fixes #4627) (#4750)
Unignored files are marked as conflicting while scanning, which is then resolved
in the subsequent pull. Automatically reconciles needed items on send-only
folders, if they do not actually differ except for internal metadata.
2018-02-25 09:39:00 +01:00

261 lines
6.6 KiB
Go

// 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 https://mozilla.org/MPL/2.0/.
package model
import (
"context"
"errors"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/ignore"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/watchaggregator"
)
var errWatchNotStarted error = errors.New("not started")
type folder struct {
stateTracker
config.FolderConfiguration
model *Model
shortID protocol.ShortID
ctx context.Context
cancel context.CancelFunc
scan folderScanner
initialScanFinished chan struct{}
pullScheduled chan struct{}
watchCancel context.CancelFunc
watchChan chan []string
restartWatchChan chan struct{}
watchErr error
watchErrMut sync.Mutex
}
func newFolder(model *Model, cfg config.FolderConfiguration) folder {
ctx, cancel := context.WithCancel(context.Background())
return folder{
stateTracker: newStateTracker(cfg.ID),
FolderConfiguration: cfg,
model: model,
shortID: model.shortID,
ctx: ctx,
cancel: cancel,
scan: newFolderScanner(cfg),
initialScanFinished: make(chan struct{}),
pullScheduled: make(chan struct{}, 1), // This needs to be 1-buffered so that we queue a pull if we're busy when it comes.
watchCancel: func() {},
watchErr: errWatchNotStarted,
watchErrMut: sync.NewMutex(),
}
}
func (f *folder) BringToFront(string) {}
func (f *folder) DelayScan(next time.Duration) {
f.scan.Delay(next)
}
func (f *folder) IgnoresUpdated() {
if f.FSWatcherEnabled {
f.scheduleWatchRestart()
}
}
func (f *folder) SchedulePull() {
select {
case f.pullScheduled <- struct{}{}:
default:
// We might be busy doing a pull and thus not reading from this
// channel. The channel is 1-buffered, so one notification will be
// queued to ensure we recheck after the pull, but beyond that we must
// make sure to not block index receiving.
}
}
func (f *folder) Jobs() ([]string, []string) {
return nil, nil
}
func (f *folder) Scan(subdirs []string) error {
<-f.initialScanFinished
return f.scan.Scan(subdirs)
}
func (f *folder) Stop() {
f.cancel()
}
// CheckHealth checks the folder for common errors, updates the folder state
// and returns the current folder error, or nil if the folder is healthy.
func (f *folder) CheckHealth() error {
err := f.getHealthError()
f.setError(err)
return err
}
func (f *folder) getHealthError() error {
// Check for folder errors, with the most serious and specific first and
// generic ones like out of space on the home disk later.
if err := f.CheckPath(); err != nil {
return err
}
if err := f.CheckFreeSpace(); err != nil {
return err
}
if err := f.model.cfg.CheckHomeFreeSpace(); err != nil {
return err
}
return nil
}
func (f *folder) scanSubdirs(subDirs []string) error {
if err := f.model.internalScanFolderSubdirs(f.ctx, f.folderID, subDirs); err != nil {
// Potentially sets the error twice, once in the scanner just
// by doing a check, and once here, if the error returned is
// the same one as returned by CheckHealth, though
// duplicate set is handled by setError.
f.setError(err)
return err
}
return nil
}
func (f *folder) scanTimerFired() {
err := f.scanSubdirs(nil)
select {
case <-f.initialScanFinished:
default:
status := "Completed"
if err != nil {
status = "Failed"
}
l.Infoln(status, "initial scan of", f.Type.String(), "folder", f.Description())
close(f.initialScanFinished)
}
f.scan.Reschedule()
}
func (f *folder) WatchError() error {
f.watchErrMut.Lock()
defer f.watchErrMut.Unlock()
return f.watchErr
}
// stopWatch immediately aborts watching and may be called asynchronously
func (f *folder) stopWatch() {
f.watchCancel()
f.watchErrMut.Lock()
f.watchErr = errWatchNotStarted
f.watchErrMut.Unlock()
}
// scheduleWatchRestart makes sure watching is restarted from the main for loop
// in a folder's Serve and thus may be called asynchronously (e.g. when ignores change).
func (f *folder) scheduleWatchRestart() {
select {
case f.restartWatchChan <- struct{}{}:
default:
// We might be busy doing a pull and thus not reading from this
// channel. The channel is 1-buffered, so one notification will be
// queued to ensure we recheck after the pull.
}
}
// restartWatch should only ever be called synchronously. If you want to use
// this asynchronously, you should probably use scheduleWatchRestart instead.
func (f *folder) restartWatch() {
f.stopWatch()
f.startWatch()
f.Scan(nil)
}
// startWatch should only ever be called synchronously. If you want to use
// this asynchronously, you should probably use scheduleWatchRestart instead.
func (f *folder) startWatch() {
ctx, cancel := context.WithCancel(f.ctx)
f.model.fmut.RLock()
ignores := f.model.folderIgnores[f.folderID]
f.model.fmut.RUnlock()
f.watchChan = make(chan []string)
f.watchCancel = cancel
go f.startWatchAsync(ctx, ignores)
}
// startWatchAsync tries to start the filesystem watching and retries every minute on failure.
// It is a convenience function that should not be used except in startWatch.
func (f *folder) startWatchAsync(ctx context.Context, ignores *ignore.Matcher) {
timer := time.NewTimer(0)
for {
select {
case <-timer.C:
eventChan, err := f.Filesystem().Watch(".", ignores, ctx, f.IgnorePerms)
f.watchErrMut.Lock()
prevErr := f.watchErr
f.watchErr = err
f.watchErrMut.Unlock()
if err != nil {
if prevErr == errWatchNotStarted {
l.Warnf("Failed to start filesystem watcher for folder %s: %v", f.Description(), err)
} else {
l.Debugf("Failed to start filesystem watcher for folder %s again: %v", f.Description(), err)
}
timer.Reset(time.Minute)
continue
}
watchaggregator.Aggregate(eventChan, f.watchChan, f.FolderConfiguration, f.model.cfg, ctx)
l.Debugln("Started filesystem watcher for folder", f.Description())
return
case <-ctx.Done():
return
}
}
}
func (f *folder) setError(err error) {
_, _, oldErr := f.getState()
if (err != nil && oldErr != nil && oldErr.Error() == err.Error()) || (err == nil && oldErr == nil) {
return
}
if err != nil {
if oldErr == nil {
l.Warnf("Error on folder %s: %v", f.Description(), err)
} else {
l.Infof("Error on folder %s changed: %q -> %q", f.Description(), oldErr, err)
}
} else {
l.Infoln("Cleared error on folder", f.Description())
}
if f.FSWatcherEnabled {
if err != nil {
f.stopWatch()
} else {
f.scheduleWatchRestart()
}
}
f.stateTracker.setError(err)
}