syncthing/lib/model/rwfolder.go

1560 lines
45 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 http://mozilla.org/MPL/2.0/.
package model
import (
"errors"
"fmt"
"io/ioutil"
"math/rand"
"os"
"path/filepath"
"sort"
"strings"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/db"
"github.com/syncthing/syncthing/lib/events"
"github.com/syncthing/syncthing/lib/ignore"
"github.com/syncthing/syncthing/lib/osutil"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/scanner"
"github.com/syncthing/syncthing/lib/symlinks"
"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/versioner"
)
// TODO: Stop on errors
func init() {
folderFactories[config.FolderTypeReadWrite] = newRWFolder
}
// A pullBlockState is passed to the puller routine for each block that needs
// to be fetched.
type pullBlockState struct {
*sharedPullerState
block protocol.BlockInfo
}
// A copyBlocksState is passed to copy routine if the file has blocks to be
// copied.
type copyBlocksState struct {
*sharedPullerState
blocks []protocol.BlockInfo
}
// Which filemode bits to preserve
const retainBits = os.ModeSetgid | os.ModeSetuid | os.ModeSticky
var (
activity = newDeviceActivity()
errNoDevice = errors.New("peers who had this file went away, or the file has changed while syncing. will retry later")
)
const (
dbUpdateHandleDir = iota
dbUpdateDeleteDir
dbUpdateHandleFile
dbUpdateDeleteFile
dbUpdateShortcutFile
)
const (
defaultCopiers = 1
defaultPullers = 16
defaultPullerSleep = 10 * time.Second
defaultPullerPause = 60 * time.Second
)
type dbUpdateJob struct {
file protocol.FileInfo
jobType int
}
type rwFolder struct {
folder
virtualMtimeRepo *db.VirtualMtimeRepo
dir string
versioner versioner.Versioner
ignorePerms bool
copiers int
pullers int
order config.PullOrder
maxConflicts int
sleep time.Duration
pause time.Duration
allowSparse bool
checkFreeSpace bool
queue *jobQueue
dbUpdates chan dbUpdateJob
pullTimer *time.Timer
remoteIndex chan struct{} // An index update was received, we should re-evaluate needs
errors map[string]string // path -> error string
errorsMut sync.Mutex
initialScanCompleted chan (struct{}) // exposed for testing
}
func newRWFolder(model *Model, cfg config.FolderConfiguration, ver versioner.Versioner) service {
f := &rwFolder{
folder: folder{
stateTracker: stateTracker{
folderID: cfg.ID,
mut: sync.NewMutex(),
},
scan: folderscan{
interval: time.Duration(cfg.RescanIntervalS) * time.Second,
timer: time.NewTimer(time.Millisecond), // The first scan should be done immediately.
now: make(chan rescanRequest),
delay: make(chan time.Duration),
},
stop: make(chan struct{}),
model: model,
},
virtualMtimeRepo: db.NewVirtualMtimeRepo(model.db, cfg.ID),
dir: cfg.Path(),
ignorePerms: cfg.IgnorePerms,
copiers: cfg.Copiers,
pullers: cfg.Pullers,
order: cfg.Order,
maxConflicts: cfg.MaxConflicts,
allowSparse: !cfg.DisableSparseFiles,
checkFreeSpace: cfg.MinDiskFreePct != 0,
versioner: ver,
queue: newJobQueue(),
pullTimer: time.NewTimer(time.Second),
remoteIndex: make(chan struct{}, 1), // This needs to be 1-buffered so that we queue a notification if we're busy doing a pull when it comes.
errorsMut: sync.NewMutex(),
initialScanCompleted: make(chan struct{}),
}
f.configureCopiersAndPullers(cfg)
return f
}
func (f *rwFolder) configureCopiersAndPullers(config config.FolderConfiguration) {
if f.copiers == 0 {
f.copiers = defaultCopiers
}
if f.pullers == 0 {
f.pullers = defaultPullers
}
if config.PullerPauseS == 0 {
f.pause = defaultPullerPause
} else {
f.pause = time.Duration(config.PullerPauseS) * time.Second
}
if config.PullerSleepS == 0 {
f.sleep = defaultPullerSleep
} else {
f.sleep = time.Duration(config.PullerSleepS) * time.Second
}
}
// Helper function to check whether either the ignorePerm flag has been
// set on the local host or the FlagNoPermBits has been set on the file/dir
// which is being pulled.
func (f *rwFolder) ignorePermissions(file protocol.FileInfo) bool {
return f.ignorePerms || file.Flags&protocol.FlagNoPermBits != 0
}
// Serve will run scans and pulls. It will return when Stop()ed or on a
// critical error.
func (f *rwFolder) Serve() {
l.Debugln(f, "starting")
defer l.Debugln(f, "exiting")
defer func() {
f.pullTimer.Stop()
f.scan.timer.Stop()
// TODO: Should there be an actual FolderStopped state?
f.setState(FolderIdle)
}()
var prevVer int64
var prevIgnoreHash string
for {
select {
case <-f.stop:
return
case <-f.remoteIndex:
prevVer = 0
f.pullTimer.Reset(0)
l.Debugln(f, "remote index updated, rescheduling pull")
case <-f.pullTimer.C:
select {
case <-f.initialScanCompleted:
default:
// We don't start pulling files until a scan has been completed.
l.Debugln(f, "skip (initial)")
f.pullTimer.Reset(f.sleep)
continue
}
f.model.fmut.RLock()
curIgnores := f.model.folderIgnores[f.folderID]
f.model.fmut.RUnlock()
if newHash := curIgnores.Hash(); newHash != prevIgnoreHash {
// The ignore patterns have changed. We need to re-evaluate if
// there are files we need now that were ignored before.
l.Debugln(f, "ignore patterns have changed, resetting prevVer")
prevVer = 0
prevIgnoreHash = newHash
}
// RemoteLocalVersion() is a fast call, doesn't touch the database.
curVer, ok := f.model.RemoteLocalVersion(f.folderID)
if !ok || curVer == prevVer {
l.Debugln(f, "skip (curVer == prevVer)", prevVer, ok)
f.pullTimer.Reset(f.sleep)
continue
}
if err := f.model.CheckFolderHealth(f.folderID); err != nil {
l.Infoln("Skipping folder", f.folderID, "pull due to folder error:", err)
f.pullTimer.Reset(f.sleep)
continue
}
l.Debugln(f, "pulling", prevVer, curVer)
f.setState(FolderSyncing)
f.clearErrors()
tries := 0
for {
tries++
changed := f.pullerIteration(curIgnores)
l.Debugln(f, "changed", changed)
if changed == 0 {
// No files were changed by the puller, so we are in
// sync. Remember the local version number and
// schedule a resync a little bit into the future.
if lv, ok := f.model.RemoteLocalVersion(f.folderID); ok && lv < curVer {
// There's a corner case where the device we needed
// files from disconnected during the puller
// iteration. The files will have been removed from
// the index, so we've concluded that we don't need
// them, but at the same time we have the local
// version that includes those files in curVer. So we
// catch the case that localVersion might have
// decreased here.
l.Debugln(f, "adjusting curVer", lv)
curVer = lv
}
prevVer = curVer
l.Debugln(f, "next pull in", f.sleep)
f.pullTimer.Reset(f.sleep)
break
}
if tries > 10 {
// We've tried a bunch of times to get in sync, but
// we're not making it. Probably there are write
// errors preventing us. Flag this with a warning and
// wait a bit longer before retrying.
l.Infof("Folder %q isn't making progress. Pausing puller for %v.", f.folderID, f.pause)
l.Debugln(f, "next pull in", f.pause)
if folderErrors := f.currentErrors(); len(folderErrors) > 0 {
events.Default.Log(events.FolderErrors, map[string]interface{}{
"folder": f.folderID,
"errors": folderErrors,
})
}
f.pullTimer.Reset(f.pause)
break
}
}
f.setState(FolderIdle)
// The reason for running the scanner from within the puller is that
// this is the easiest way to make sure we are not doing both at the
// same time.
case <-f.scan.timer.C:
err := f.scanSubdirsIfHealthy(nil)
f.scan.reschedule()
if err != nil {
continue
}
select {
case <-f.initialScanCompleted:
default:
l.Infoln("Completed initial scan (rw) of folder", f.folderID)
close(f.initialScanCompleted)
}
case req := <-f.scan.now:
req.err <- f.scanSubdirsIfHealthy(req.subdirs)
case next := <-f.scan.delay:
f.scan.timer.Reset(next)
}
}
}
func (f *rwFolder) IndexUpdated() {
select {
case f.remoteIndex <- 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 *rwFolder) String() string {
return fmt.Sprintf("rwFolder/%s@%p", f.folderID, f)
}
// pullerIteration runs a single puller iteration for the given folder and
// returns the number items that should have been synced (even those that
// might have failed). One puller iteration handles all files currently
// flagged as needed in the folder.
func (f *rwFolder) pullerIteration(ignores *ignore.Matcher) int {
pullChan := make(chan pullBlockState)
copyChan := make(chan copyBlocksState)
finisherChan := make(chan *sharedPullerState)
updateWg := sync.NewWaitGroup()
copyWg := sync.NewWaitGroup()
pullWg := sync.NewWaitGroup()
doneWg := sync.NewWaitGroup()
l.Debugln(f, "c", f.copiers, "p", f.pullers)
f.dbUpdates = make(chan dbUpdateJob)
updateWg.Add(1)
go func() {
// dbUpdaterRoutine finishes when f.dbUpdates is closed
f.dbUpdaterRoutine()
updateWg.Done()
}()
for i := 0; i < f.copiers; i++ {
copyWg.Add(1)
go func() {
// copierRoutine finishes when copyChan is closed
f.copierRoutine(copyChan, pullChan, finisherChan)
copyWg.Done()
}()
}
for i := 0; i < f.pullers; i++ {
pullWg.Add(1)
go func() {
// pullerRoutine finishes when pullChan is closed
f.pullerRoutine(pullChan, finisherChan)
pullWg.Done()
}()
}
doneWg.Add(1)
// finisherRoutine finishes when finisherChan is closed
go func() {
f.finisherRoutine(finisherChan)
doneWg.Done()
}()
f.model.fmut.RLock()
folderFiles := f.model.folderFiles[f.folderID]
f.model.fmut.RUnlock()
// !!!
// WithNeed takes a database snapshot (by necessity). By the time we've
// handled a bunch of files it might have become out of date and we might
// be attempting to sync with an old version of a file...
// !!!
changed := 0
fileDeletions := map[string]protocol.FileInfo{}
dirDeletions := []protocol.FileInfo{}
buckets := map[string][]protocol.FileInfo{}
handleFile := func(fi protocol.FileInfo) bool {
switch {
case fi.IsDeleted():
// A deleted file, directory or symlink
if fi.IsDirectory() {
dirDeletions = append(dirDeletions, fi)
} else {
fileDeletions[fi.Name] = fi
df, ok := f.model.CurrentFolderFile(f.folderID, fi.Name)
// Local file can be already deleted, but with a lower version
// number, hence the deletion coming in again as part of
// WithNeed, furthermore, the file can simply be of the wrong
// type if we haven't yet managed to pull it.
if ok && !df.IsDeleted() && !df.IsSymlink() && !df.IsDirectory() {
// Put files into buckets per first hash
key := string(df.Blocks[0].Hash)
buckets[key] = append(buckets[key], df)
}
}
case fi.IsDirectory() && !fi.IsSymlink():
// A new or changed directory
l.Debugln("Creating directory", fi.Name)
f.handleDir(fi)
default:
return false
}
return true
}
folderFiles.WithNeed(protocol.LocalDeviceID, func(intf db.FileIntf) bool {
// Needed items are delivered sorted lexicographically. We'll handle
// directories as they come along, so parents before children. Files
// are queued and the order may be changed later.
file := intf.(protocol.FileInfo)
if ignores.Match(file.Name).IsIgnored() {
// This is an ignored file. Skip it, continue iteration.
return true
}
l.Debugln(f, "handling", file.Name)
if !handleFile(file) {
// A new or changed file or symlink. This is the only case where we
// do stuff concurrently in the background
f.queue.Push(file.Name, file.Size(), file.Modified)
}
changed++
return true
})
// Reorder the file queue according to configuration
switch f.order {
case config.OrderRandom:
f.queue.Shuffle()
case config.OrderAlphabetic:
// The queue is already in alphabetic order.
case config.OrderSmallestFirst:
f.queue.SortSmallestFirst()
case config.OrderLargestFirst:
f.queue.SortLargestFirst()
case config.OrderOldestFirst:
f.queue.SortOldestFirst()
case config.OrderNewestFirst:
f.queue.SortNewestFirst()
}
// Process the file queue
nextFile:
for {
select {
case <-f.stop:
// Stop processing files if the puller has been told to stop.
break
default:
}
fileName, ok := f.queue.Pop()
if !ok {
break
}
fi, ok := f.model.CurrentGlobalFile(f.folderID, fileName)
if !ok {
// File is no longer in the index. Mark it as done and drop it.
f.queue.Done(fileName)
continue
}
// Handles races where an index update arrives changing what the file
// is between queueing and retrieving it from the queue, effectively
// changing how the file should be handled.
if handleFile(fi) {
continue
}
if !fi.IsSymlink() {
key := string(fi.Blocks[0].Hash)
for i, candidate := range buckets[key] {
if scanner.BlocksEqual(candidate.Blocks, fi.Blocks) {
// Remove the candidate from the bucket
lidx := len(buckets[key]) - 1
buckets[key][i] = buckets[key][lidx]
buckets[key] = buckets[key][:lidx]
// candidate is our current state of the file, where as the
// desired state with the delete bit set is in the deletion
// map.
desired := fileDeletions[candidate.Name]
// Remove the pending deletion (as we perform it by renaming)
delete(fileDeletions, candidate.Name)
f.renameFile(desired, fi)
f.queue.Done(fileName)
continue nextFile
}
}
}
// Not a rename or a symlink, deal with it.
f.handleFile(fi, copyChan, finisherChan)
}
// Signal copy and puller routines that we are done with the in data for
// this iteration. Wait for them to finish.
close(copyChan)
copyWg.Wait()
close(pullChan)
pullWg.Wait()
// Signal the finisher chan that there will be no more input.
close(finisherChan)
// Wait for the finisherChan to finish.
doneWg.Wait()
for _, file := range fileDeletions {
l.Debugln("Deleting file", file.Name)
f.deleteFile(file)
}
for i := range dirDeletions {
dir := dirDeletions[len(dirDeletions)-i-1]
l.Debugln("Deleting dir", dir.Name)
f.deleteDir(dir, ignores)
}
// Wait for db updates to complete
close(f.dbUpdates)
updateWg.Wait()
return changed
}
// handleDir creates or updates the given directory
func (f *rwFolder) handleDir(file protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": file.Name,
"type": "dir",
"action": "update",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": file.Name,
"error": events.Error(err),
"type": "dir",
"action": "update",
})
}()
realName := filepath.Join(f.dir, file.Name)
mode := os.FileMode(file.Flags & 0777)
if f.ignorePermissions(file) {
mode = 0777
}
if shouldDebug() {
curFile, _ := f.model.CurrentFolderFile(f.folderID, file.Name)
l.Debugf("need dir\n\t%v\n\t%v", file, curFile)
}
info, err := osutil.Lstat(realName)
switch {
// There is already something under that name, but it's a file/link.
// Most likely a file/link is getting replaced with a directory.
// Remove the file/link and fall through to directory creation.
case err == nil && (!info.IsDir() || info.Mode()&os.ModeSymlink != 0):
err = osutil.InWritableDir(osutil.Remove, realName)
if err != nil {
l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
return
}
fallthrough
// The directory doesn't exist, so we create it with the right
// mode bits from the start.
case err != nil && os.IsNotExist(err):
// We declare a function that acts on only the path name, so
// we can pass it to InWritableDir. We use a regular Mkdir and
// not MkdirAll because the parent should already exist.
mkdir := func(path string) error {
err = os.Mkdir(path, mode)
if err != nil || f.ignorePermissions(file) {
return err
}
// Stat the directory so we can check its permissions.
info, err := osutil.Lstat(path)
if err != nil {
return err
}
// Mask for the bits we want to preserve and add them in to the
// directories permissions.
return os.Chmod(path, mode|(info.Mode()&retainBits))
}
if err = osutil.InWritableDir(mkdir, realName); err == nil {
f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleDir}
} else {
l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
}
return
// Weird error when stat()'ing the dir. Probably won't work to do
// anything else with it if we can't even stat() it.
case err != nil:
l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
return
}
// The directory already exists, so we just correct the mode bits. (We
// don't handle modification times on directories, because that sucks...)
// It's OK to change mode bits on stuff within non-writable directories.
if f.ignorePermissions(file) {
f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleDir}
} else if err := os.Chmod(realName, mode|(info.Mode()&retainBits)); err == nil {
f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleDir}
} else {
l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
}
}
// deleteDir attempts to delete the given directory
func (f *rwFolder) deleteDir(file protocol.FileInfo, matcher *ignore.Matcher) {
var err error
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": file.Name,
"type": "dir",
"action": "delete",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": file.Name,
"error": events.Error(err),
"type": "dir",
"action": "delete",
})
}()
realName := filepath.Join(f.dir, file.Name)
// Delete any temporary files lying around in the directory
dir, _ := os.Open(realName)
if dir != nil {
files, _ := dir.Readdirnames(-1)
for _, dirFile := range files {
if defTempNamer.IsTemporary(dirFile) || (matcher != nil && matcher.Match(filepath.Join(file.Name, dirFile)).IsDeletable()) {
osutil.InWritableDir(osutil.Remove, filepath.Join(realName, dirFile))
}
}
dir.Close()
}
err = osutil.InWritableDir(osutil.Remove, realName)
if err == nil || os.IsNotExist(err) {
// It was removed or it doesn't exist to start with
f.dbUpdates <- dbUpdateJob{file, dbUpdateDeleteDir}
} else if _, serr := os.Lstat(realName); serr != nil && !os.IsPermission(serr) {
// We get an error just looking at the directory, and it's not a
// permission problem. Lets assume the error is in fact some variant
// of "file does not exist" (possibly expressed as some parent being a
// file and not a directory etc) and that the delete is handled.
f.dbUpdates <- dbUpdateJob{file, dbUpdateDeleteDir}
} else {
l.Infof("Puller (folder %q, dir %q): delete: %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
}
}
// deleteFile attempts to delete the given file
func (f *rwFolder) deleteFile(file protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": file.Name,
"type": "file",
"action": "delete",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": file.Name,
"error": events.Error(err),
"type": "file",
"action": "delete",
})
}()
realName := filepath.Join(f.dir, file.Name)
cur, ok := f.model.CurrentFolderFile(f.folderID, file.Name)
if ok && f.inConflict(cur.Version, file.Version) {
// There is a conflict here. Move the file to a conflict copy instead
// of deleting. Also merge with the version vector we had, to indicate
// we have resolved the conflict.
file.Version = file.Version.Merge(cur.Version)
err = osutil.InWritableDir(f.moveForConflict, realName)
} else if f.versioner != nil {
err = osutil.InWritableDir(f.versioner.Archive, realName)
} else {
err = osutil.InWritableDir(osutil.Remove, realName)
}
if err == nil || os.IsNotExist(err) {
// It was removed or it doesn't exist to start with
f.dbUpdates <- dbUpdateJob{file, dbUpdateDeleteFile}
} else if _, serr := os.Lstat(realName); serr != nil && !os.IsPermission(serr) {
// We get an error just looking at the file, and it's not a permission
// problem. Lets assume the error is in fact some variant of "file
// does not exist" (possibly expressed as some parent being a file and
// not a directory etc) and that the delete is handled.
f.dbUpdates <- dbUpdateJob{file, dbUpdateDeleteFile}
} else {
l.Infof("Puller (folder %q, file %q): delete: %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
}
}
// renameFile attempts to rename an existing file to a destination
// and set the right attributes on it.
func (f *rwFolder) renameFile(source, target protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": source.Name,
"type": "file",
"action": "delete",
})
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": target.Name,
"type": "file",
"action": "update",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": source.Name,
"error": events.Error(err),
"type": "file",
"action": "delete",
})
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": target.Name,
"error": events.Error(err),
"type": "file",
"action": "update",
})
}()
l.Debugln(f, "taking rename shortcut", source.Name, "->", target.Name)
from := filepath.Join(f.dir, source.Name)
to := filepath.Join(f.dir, target.Name)
if f.versioner != nil {
err = osutil.Copy(from, to)
if err == nil {
err = osutil.InWritableDir(f.versioner.Archive, from)
}
} else {
err = osutil.TryRename(from, to)
}
if err == nil {
// The file was renamed, so we have handled both the necessary delete
// of the source and the creation of the target. Fix-up the metadata,
// and update the local index of the target file.
f.dbUpdates <- dbUpdateJob{source, dbUpdateDeleteFile}
err = f.shortcutFile(target)
if err != nil {
l.Infof("Puller (folder %q, file %q): rename from %q metadata: %v", f.folderID, target.Name, source.Name, err)
f.newError(target.Name, err)
return
}
f.dbUpdates <- dbUpdateJob{target, dbUpdateHandleFile}
} else {
// We failed the rename so we have a source file that we still need to
// get rid of. Attempt to delete it instead so that we make *some*
// progress. The target is unhandled.
err = osutil.InWritableDir(osutil.Remove, from)
if err != nil {
l.Infof("Puller (folder %q, file %q): delete %q after failed rename: %v", f.folderID, target.Name, source.Name, err)
f.newError(target.Name, err)
return
}
f.dbUpdates <- dbUpdateJob{source, dbUpdateDeleteFile}
}
}
// This is the flow of data and events here, I think...
//
// +-----------------------+
// | | - - - - > ItemStarted
// | handleFile | - - - - > ItemFinished (on shortcuts)
// | |
// +-----------------------+
// |
// | copyChan (copyBlocksState; unless shortcut taken)
// |
// | +-----------------------+
// | | +-----------------------+
// +--->| | |
// | | copierRoutine |
// +-| |
// +-----------------------+
// |
// | pullChan (sharedPullerState)
// |
// | +-----------------------+
// | | +-----------------------+
// +-->| | |
// | | pullerRoutine |
// +-| |
// +-----------------------+
// |
// | finisherChan (sharedPullerState)
// |
// | +-----------------------+
// | | |
// +-->| finisherRoutine | - - - - > ItemFinished
// | |
// +-----------------------+
// handleFile queues the copies and pulls as necessary for a single new or
// changed file.
func (f *rwFolder) handleFile(file protocol.FileInfo, copyChan chan<- copyBlocksState, finisherChan chan<- *sharedPullerState) {
curFile, hasCurFile := f.model.CurrentFolderFile(f.folderID, file.Name)
if hasCurFile && len(curFile.Blocks) == len(file.Blocks) && scanner.BlocksEqual(curFile.Blocks, file.Blocks) {
// We are supposed to copy the entire file, and then fetch nothing. We
// are only updating metadata, so we don't actually *need* to make the
// copy.
l.Debugln(f, "taking shortcut on", file.Name)
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": file.Name,
"type": "file",
"action": "metadata",
})
f.queue.Done(file.Name)
var err error
if file.IsSymlink() {
err = f.shortcutSymlink(file)
} else {
err = f.shortcutFile(file)
}
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": file.Name,
"error": events.Error(err),
"type": "file",
"action": "metadata",
})
if err != nil {
l.Infoln("Puller: shortcut:", err)
f.newError(file.Name, err)
} else {
f.dbUpdates <- dbUpdateJob{file, dbUpdateShortcutFile}
}
return
}
// Figure out the absolute filenames we need once and for all
tempName := filepath.Join(f.dir, defTempNamer.TempName(file.Name))
realName := filepath.Join(f.dir, file.Name)
if hasCurFile && !curFile.IsDirectory() && !curFile.IsSymlink() {
// Check that the file on disk is what we expect it to be according to
// the database. If there's a mismatch here, there might be local
// changes that we don't know about yet and we should scan before
// touching the file. If we can't stat the file we'll just pull it.
if info, err := osutil.Lstat(realName); err == nil {
mtime := f.virtualMtimeRepo.GetMtime(file.Name, info.ModTime())
if mtime.Unix() != curFile.Modified || info.Size() != curFile.Size() {
l.Debugln("file modified but not rescanned; not pulling:", realName)
// Scan() is synchronous (i.e. blocks until the scan is
// completed and returns an error), but a scan can't happen
// while we're in the puller routine. Request the scan in the
// background and it'll be handled when the current pulling
// sweep is complete. As we do retries, we'll queue the scan
// for this file up to ten times, but the last nine of those
// scans will be cheap...
go f.scan.Scan([]string{file.Name})
return
}
}
}
scanner.PopulateOffsets(file.Blocks)
var blocks []protocol.BlockInfo
var blocksSize int64
var reused []int32
// Check for an old temporary file which might have some blocks we could
// reuse.
tempBlocks, err := scanner.HashFile(tempName, protocol.BlockSize, 0, nil)
if err == nil {
// Check for any reusable blocks in the temp file
tempCopyBlocks, _ := scanner.BlockDiff(tempBlocks, file.Blocks)
// block.String() returns a string unique to the block
existingBlocks := make(map[string]struct{}, len(tempCopyBlocks))
for _, block := range tempCopyBlocks {
existingBlocks[block.String()] = struct{}{}
}
// Since the blocks are already there, we don't need to get them.
for i, block := range file.Blocks {
_, ok := existingBlocks[block.String()]
if !ok {
blocks = append(blocks, block)
blocksSize += int64(block.Size)
} else {
reused = append(reused, int32(i))
}
}
// The sharedpullerstate will know which flags to use when opening the
// temp file depending if we are reusing any blocks or not.
if len(reused) == 0 {
// Otherwise, discard the file ourselves in order for the
// sharedpuller not to panic when it fails to exclusively create a
// file which already exists
osutil.InWritableDir(osutil.Remove, tempName)
}
} else {
// Copy the blocks, as we don't want to shuffle them on the FileInfo
blocks = append(blocks, file.Blocks...)
blocksSize = file.Size()
}
if f.checkFreeSpace {
if free, err := osutil.DiskFreeBytes(f.dir); err == nil && free < blocksSize {
l.Warnf(`Folder "%s": insufficient disk space in %s for %s: have %.2f MiB, need %.2f MiB`, f.folderID, f.dir, file.Name, float64(free)/1024/1024, float64(blocksSize)/1024/1024)
f.newError(file.Name, errors.New("insufficient space"))
return
}
}
// Shuffle the blocks
for i := range blocks {
j := rand.Intn(i + 1)
blocks[i], blocks[j] = blocks[j], blocks[i]
}
events.Default.Log(events.ItemStarted, map[string]string{
"folder": f.folderID,
"item": file.Name,
"type": "file",
"action": "update",
})
s := sharedPullerState{
file: file,
folder: f.folderID,
tempName: tempName,
realName: realName,
copyTotal: len(blocks),
copyNeeded: len(blocks),
reused: len(reused),
updated: time.Now(),
available: reused,
availableUpdated: time.Now(),
ignorePerms: f.ignorePermissions(file),
version: curFile.Version,
mut: sync.NewRWMutex(),
sparse: f.allowSparse,
}
l.Debugf("%v need file %s; copy %d, reused %v", f, file.Name, len(blocks), reused)
cs := copyBlocksState{
sharedPullerState: &s,
blocks: blocks,
}
copyChan <- cs
}
// shortcutFile sets file mode and modification time, when that's the only
// thing that has changed.
func (f *rwFolder) shortcutFile(file protocol.FileInfo) error {
realName := filepath.Join(f.dir, file.Name)
if !f.ignorePermissions(file) {
if err := os.Chmod(realName, os.FileMode(file.Flags&0777)); err != nil {
l.Infof("Puller (folder %q, file %q): shortcut: chmod: %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
return err
}
}
t := time.Unix(file.Modified, 0)
if err := os.Chtimes(realName, t, t); err != nil {
// Try using virtual mtimes
info, err := os.Stat(realName)
if err != nil {
l.Infof("Puller (folder %q, file %q): shortcut: unable to stat file: %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
return err
}
f.virtualMtimeRepo.UpdateMtime(file.Name, info.ModTime(), t)
}
// This may have been a conflict. We should merge the version vectors so
// that our clock doesn't move backwards.
if cur, ok := f.model.CurrentFolderFile(f.folderID, file.Name); ok {
file.Version = file.Version.Merge(cur.Version)
}
return nil
}
// shortcutSymlink changes the symlinks type if necessary.
func (f *rwFolder) shortcutSymlink(file protocol.FileInfo) (err error) {
tt := symlinks.TargetFile
if file.IsDirectory() {
tt = symlinks.TargetDirectory
}
err = symlinks.ChangeType(filepath.Join(f.dir, file.Name), tt)
if err != nil {
l.Infof("Puller (folder %q, file %q): symlink shortcut: %v", f.folderID, file.Name, err)
f.newError(file.Name, err)
}
return
}
// copierRoutine reads copierStates until the in channel closes and performs
// the relevant copies when possible, or passes it to the puller routine.
func (f *rwFolder) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBlockState, out chan<- *sharedPullerState) {
buf := make([]byte, protocol.BlockSize)
for state := range in {
dstFd, err := state.tempFile()
if err != nil {
// Nothing more to do for this failed file, since we couldn't create a temporary for it.
out <- state.sharedPullerState
continue
}
if f.model.progressEmitter != nil {
f.model.progressEmitter.Register(state.sharedPullerState)
}
folderRoots := make(map[string]string)
var folders []string
f.model.fmut.RLock()
for folder, cfg := range f.model.folderCfgs {
folderRoots[folder] = cfg.Path()
folders = append(folders, folder)
}
f.model.fmut.RUnlock()
for _, block := range state.blocks {
if f.allowSparse && state.reused == 0 && block.IsEmpty() {
// The block is a block of all zeroes, and we are not reusing
// a temp file, so there is no need to do anything with it.
// If we were reusing a temp file and had this block to copy,
// it would be because the block in the temp file was *not* a
// block of all zeroes, so then we should not skip it.
// Pretend we copied it.
state.copiedFromOrigin()
continue
}
buf = buf[:int(block.Size)]
found := f.model.finder.Iterate(folders, block.Hash, func(folder, file string, index int32) bool {
fd, err := os.Open(filepath.Join(folderRoots[folder], file))
if err != nil {
return false
}
_, err = fd.ReadAt(buf, protocol.BlockSize*int64(index))
fd.Close()
if err != nil {
return false
}
hash, err := scanner.VerifyBuffer(buf, block)
if err != nil {
if hash != nil {
l.Debugf("Finder block mismatch in %s:%s:%d expected %q got %q", folder, file, index, block.Hash, hash)
err = f.model.finder.Fix(folder, file, index, block.Hash, hash)
if err != nil {
l.Warnln("finder fix:", err)
}
} else {
l.Debugln("Finder failed to verify buffer", err)
}
return false
}
_, err = dstFd.WriteAt(buf, block.Offset)
if err != nil {
state.fail("dst write", err)
}
if file == state.file.Name {
state.copiedFromOrigin()
}
return true
})
if state.failed() != nil {
break
}
if !found {
state.pullStarted()
ps := pullBlockState{
sharedPullerState: state.sharedPullerState,
block: block,
}
pullChan <- ps
} else {
state.copyDone(block)
}
}
out <- state.sharedPullerState
}
}
func (f *rwFolder) pullerRoutine(in <-chan pullBlockState, out chan<- *sharedPullerState) {
for state := range in {
if state.failed() != nil {
out <- state.sharedPullerState
continue
}
// Get an fd to the temporary file. Technically we don't need it until
// after fetching the block, but if we run into an error here there is
// no point in issuing the request to the network.
fd, err := state.tempFile()
if err != nil {
out <- state.sharedPullerState
continue
}
if f.allowSparse && state.reused == 0 && state.block.IsEmpty() {
// There is no need to request a block of all zeroes. Pretend we
// requested it and handled it correctly.
state.pullDone(state.block)
out <- state.sharedPullerState
continue
}
var lastError error
candidates := f.model.Availability(f.folderID, state.file.Name, state.file.Version, state.block)
for {
// Select the least busy device to pull the block from. If we found no
// feasible device at all, fail the block (and in the long run, the
// file).
selected, found := activity.leastBusy(candidates)
if !found {
if lastError != nil {
state.fail("pull", lastError)
} else {
state.fail("pull", errNoDevice)
}
break
}
candidates = removeAvailability(candidates, selected)
// Fetch the block, while marking the selected device as in use so that
// leastBusy can select another device when someone else asks.
activity.using(selected)
buf, lastError := f.model.requestGlobal(selected.ID, f.folderID, state.file.Name, state.block.Offset, int(state.block.Size), state.block.Hash, selected.FromTemporary)
activity.done(selected)
if lastError != nil {
l.Debugln("request:", f.folderID, state.file.Name, state.block.Offset, state.block.Size, "returned error:", lastError)
continue
}
// Verify that the received block matches the desired hash, if not
// try pulling it from another device.
_, lastError = scanner.VerifyBuffer(buf, state.block)
if lastError != nil {
l.Debugln("request:", f.folderID, state.file.Name, state.block.Offset, state.block.Size, "hash mismatch")
continue
}
// Save the block data we got from the cluster
_, err = fd.WriteAt(buf, state.block.Offset)
if err != nil {
state.fail("save", err)
} else {
state.pullDone(state.block)
}
break
}
out <- state.sharedPullerState
}
}
func (f *rwFolder) performFinish(state *sharedPullerState) error {
// Set the correct permission bits on the new file
if !f.ignorePermissions(state.file) {
if err := os.Chmod(state.tempName, os.FileMode(state.file.Flags&0777)); err != nil {
return err
}
}
// Set the correct timestamp on the new file
t := time.Unix(state.file.Modified, 0)
if err := os.Chtimes(state.tempName, t, t); err != nil {
// Try using virtual mtimes instead
info, err := os.Stat(state.tempName)
if err != nil {
return err
}
f.virtualMtimeRepo.UpdateMtime(state.file.Name, info.ModTime(), t)
}
if stat, err := osutil.Lstat(state.realName); err == nil {
// There is an old file or directory already in place. We need to
// handle that.
switch {
case stat.IsDir() || stat.Mode()&os.ModeSymlink != 0:
// It's a directory or a symlink. These are not versioned or
// archived for conflicts, only removed (which of course fails for
// non-empty directories).
// TODO: This is the place where we want to remove temporary files
// and future hard ignores before attempting a directory delete.
// Should share code with f.deletDir().
if err = osutil.InWritableDir(osutil.Remove, state.realName); err != nil {
return err
}
case f.inConflict(state.version, state.file.Version):
// The new file has been changed in conflict with the existing one. We
// should file it away as a conflict instead of just removing or
// archiving. Also merge with the version vector we had, to indicate
// we have resolved the conflict.
state.file.Version = state.file.Version.Merge(state.version)
if err = osutil.InWritableDir(f.moveForConflict, state.realName); err != nil {
return err
}
case f.versioner != nil:
// If we should use versioning, let the versioner archive the old
// file before we replace it. Archiving a non-existent file is not
// an error.
if err = f.versioner.Archive(state.realName); err != nil {
return err
}
}
}
// Replace the original content with the new one
if err := osutil.Rename(state.tempName, state.realName); err != nil {
return err
}
// If it's a symlink, the target of the symlink is inside the file.
if state.file.IsSymlink() {
content, err := ioutil.ReadFile(state.realName)
if err != nil {
return err
}
// Remove the file, and replace it with a symlink.
err = osutil.InWritableDir(func(path string) error {
os.Remove(path)
tt := symlinks.TargetFile
if state.file.IsDirectory() {
tt = symlinks.TargetDirectory
}
return symlinks.Create(path, string(content), tt)
}, state.realName)
if err != nil {
return err
}
}
// Record the updated file in the index
f.dbUpdates <- dbUpdateJob{state.file, dbUpdateHandleFile}
return nil
}
func (f *rwFolder) finisherRoutine(in <-chan *sharedPullerState) {
for state := range in {
if closed, err := state.finalClose(); closed {
l.Debugln(f, "closing", state.file.Name)
f.queue.Done(state.file.Name)
if err == nil {
err = f.performFinish(state)
}
if err != nil {
l.Infoln("Puller: final:", err)
f.newError(state.file.Name, err)
}
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": f.folderID,
"item": state.file.Name,
"error": events.Error(err),
"type": "file",
"action": "update",
})
if f.model.progressEmitter != nil {
f.model.progressEmitter.Deregister(state)
}
}
}
}
// Moves the given filename to the front of the job queue
func (f *rwFolder) BringToFront(filename string) {
f.queue.BringToFront(filename)
}
func (f *rwFolder) Jobs() ([]string, []string) {
return f.queue.Jobs()
}
// dbUpdaterRoutine aggregates db updates and commits them in batches no
// larger than 1000 items, and no more delayed than 2 seconds.
func (f *rwFolder) dbUpdaterRoutine() {
const (
maxBatchSize = 1000
maxBatchTime = 2 * time.Second
)
batch := make([]dbUpdateJob, 0, maxBatchSize)
files := make([]protocol.FileInfo, 0, maxBatchSize)
tick := time.NewTicker(maxBatchTime)
defer tick.Stop()
handleBatch := func() {
found := false
var lastFile protocol.FileInfo
for _, job := range batch {
files = append(files, job.file)
if job.file.IsInvalid() || (job.file.IsDirectory() && !job.file.IsSymlink()) {
continue
}
if job.jobType&(dbUpdateHandleFile|dbUpdateDeleteFile) == 0 {
continue
}
found = true
lastFile = job.file
}
// All updates to file/folder objects that originated remotely
// (across the network) use this call to updateLocals
f.model.updateLocalsFromPulling(f.folderID, files)
if found {
f.model.receivedFile(f.folderID, lastFile)
}
batch = batch[:0]
files = files[:0]
}
loop:
for {
select {
case job, ok := <-f.dbUpdates:
if !ok {
break loop
}
job.file.LocalVersion = 0
batch = append(batch, job)
if len(batch) == maxBatchSize {
handleBatch()
}
case <-tick.C:
if len(batch) > 0 {
handleBatch()
}
}
}
if len(batch) > 0 {
handleBatch()
}
}
func (f *rwFolder) inConflict(current, replacement protocol.Vector) bool {
if current.Concurrent(replacement) {
// Obvious case
return true
}
if replacement.Counter(f.model.shortID) > current.Counter(f.model.shortID) {
// The replacement file contains a higher version for ourselves than
// what we have. This isn't supposed to be possible, since it's only
// we who can increment that counter. We take it as a sign that
// something is wrong (our index may have been corrupted or removed)
// and flag it as a conflict.
return true
}
return false
}
func removeAvailability(availabilities []Availability, availability Availability) []Availability {
for i := range availabilities {
if availabilities[i] == availability {
availabilities[i] = availabilities[len(availabilities)-1]
return availabilities[:len(availabilities)-1]
}
}
return availabilities
}
func (f *rwFolder) moveForConflict(name string) error {
if strings.Contains(filepath.Base(name), ".sync-conflict-") {
l.Infoln("Conflict for", name, "which is already a conflict copy; not copying again.")
if err := osutil.Remove(name); err != nil && !os.IsNotExist(err) {
return err
}
return nil
}
if f.maxConflicts == 0 {
if err := osutil.Remove(name); err != nil && !os.IsNotExist(err) {
return err
}
return nil
}
ext := filepath.Ext(name)
withoutExt := name[:len(name)-len(ext)]
newName := withoutExt + time.Now().Format(".sync-conflict-20060102-150405") + ext
err := os.Rename(name, newName)
if os.IsNotExist(err) {
// We were supposed to move a file away but it does not exist. Either
// the user has already moved it away, or the conflict was between a
// remote modification and a local delete. In either way it does not
// matter, go ahead as if the move succeeded.
err = nil
}
if f.maxConflicts > -1 {
matches, gerr := osutil.Glob(withoutExt + ".sync-conflict-????????-??????" + ext)
if gerr == nil && len(matches) > f.maxConflicts {
sort.Sort(sort.Reverse(sort.StringSlice(matches)))
for _, match := range matches[f.maxConflicts:] {
gerr = osutil.Remove(match)
if gerr != nil {
l.Debugln(f, "removing extra conflict", gerr)
}
}
} else if gerr != nil {
l.Debugln(f, "globbing for conflicts", gerr)
}
}
return err
}
func (f *rwFolder) newError(path string, err error) {
f.errorsMut.Lock()
defer f.errorsMut.Unlock()
// We might get more than one error report for a file (i.e. error on
// Write() followed by Close()); we keep the first error as that is
// probably closer to the root cause.
if _, ok := f.errors[path]; ok {
return
}
f.errors[path] = err.Error()
}
func (f *rwFolder) clearErrors() {
f.errorsMut.Lock()
f.errors = make(map[string]string)
f.errorsMut.Unlock()
}
func (f *rwFolder) currentErrors() []fileError {
f.errorsMut.Lock()
errors := make([]fileError, 0, len(f.errors))
for path, err := range f.errors {
errors = append(errors, fileError{path, err})
}
sort.Sort(fileErrorList(errors))
f.errorsMut.Unlock()
return errors
}
// A []fileError is sent as part of an event and will be JSON serialized.
type fileError struct {
Path string `json:"path"`
Err string `json:"error"`
}
type fileErrorList []fileError
func (l fileErrorList) Len() int {
return len(l)
}
func (l fileErrorList) Less(a, b int) bool {
return l[a].Path < l[b].Path
}
func (l fileErrorList) Swap(a, b int) {
l[a], l[b] = l[b], l[a]
}