syncthing/internal/model/rwfolder.go
2015-04-29 15:59:47 +02:00

1259 lines
34 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"
"time"
"github.com/syncthing/protocol"
"github.com/syncthing/syncthing/internal/config"
"github.com/syncthing/syncthing/internal/db"
"github.com/syncthing/syncthing/internal/events"
"github.com/syncthing/syncthing/internal/ignore"
"github.com/syncthing/syncthing/internal/osutil"
"github.com/syncthing/syncthing/internal/scanner"
"github.com/syncthing/syncthing/internal/symlinks"
"github.com/syncthing/syncthing/internal/sync"
"github.com/syncthing/syncthing/internal/versioner"
)
// TODO: Stop on errors
const (
pauseIntv = 60 * time.Second
nextPullIntv = 10 * time.Second
checkPullIntv = 1 * time.Second
)
// 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
}
var (
activity = newDeviceActivity()
errNoDevice = errors.New("no available source device")
)
type rwFolder struct {
stateTracker
model *Model
progressEmitter *ProgressEmitter
folder string
dir string
scanIntv time.Duration
versioner versioner.Versioner
ignorePerms bool
lenientMtimes bool
copiers int
pullers int
shortID uint64
order config.PullOrder
stop chan struct{}
queue *jobQueue
dbUpdates chan protocol.FileInfo
}
func newRWFolder(m *Model, shortID uint64, cfg config.FolderConfiguration) *rwFolder {
return &rwFolder{
stateTracker: stateTracker{
folder: cfg.ID,
mut: sync.NewMutex(),
},
model: m,
progressEmitter: m.progressEmitter,
folder: cfg.ID,
dir: cfg.Path(),
scanIntv: time.Duration(cfg.RescanIntervalS) * time.Second,
ignorePerms: cfg.IgnorePerms,
lenientMtimes: cfg.LenientMtimes,
copiers: cfg.Copiers,
pullers: cfg.Pullers,
shortID: shortID,
order: cfg.Order,
stop: make(chan struct{}),
queue: newJobQueue(),
}
}
// Serve will run scans and pulls. It will return when Stop()ed or on a
// critical error.
func (p *rwFolder) Serve() {
if debug {
l.Debugln(p, "starting")
defer l.Debugln(p, "exiting")
}
pullTimer := time.NewTimer(checkPullIntv)
scanTimer := time.NewTimer(time.Millisecond) // The first scan should be done immediately.
defer func() {
pullTimer.Stop()
scanTimer.Stop()
// TODO: Should there be an actual FolderStopped state?
p.setState(FolderIdle)
}()
var prevVer int64
var prevIgnoreHash string
rescheduleScan := func() {
if p.scanIntv == 0 {
// We should not run scans, so it should not be rescheduled.
return
}
// Sleep a random time between 3/4 and 5/4 of the configured interval.
sleepNanos := (p.scanIntv.Nanoseconds()*3 + rand.Int63n(2*p.scanIntv.Nanoseconds())) / 4
intv := time.Duration(sleepNanos) * time.Nanosecond
if debug {
l.Debugln(p, "next rescan in", intv)
}
scanTimer.Reset(intv)
}
// We don't start pulling files until a scan has been completed.
initialScanCompleted := false
for {
select {
case <-p.stop:
return
// TODO: We could easily add a channel here for notifications from
// Index(), so that we immediately start a pull when new index
// information is available. Before that though, I'd like to build a
// repeatable benchmark of how long it takes to sync a change from
// device A to device B, so we have something to work against.
case <-pullTimer.C:
if !initialScanCompleted {
if debug {
l.Debugln(p, "skip (initial)")
}
pullTimer.Reset(nextPullIntv)
continue
}
p.model.fmut.RLock()
curIgnores := p.model.folderIgnores[p.folder]
p.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.
if debug {
l.Debugln(p, "ignore patterns have changed, resetting prevVer")
}
prevVer = 0
prevIgnoreHash = newHash
}
// RemoteLocalVersion() is a fast call, doesn't touch the database.
curVer := p.model.RemoteLocalVersion(p.folder)
if curVer == prevVer {
if debug {
l.Debugln(p, "skip (curVer == prevVer)", prevVer)
}
pullTimer.Reset(checkPullIntv)
continue
}
if debug {
l.Debugln(p, "pulling", prevVer, curVer)
}
p.setState(FolderSyncing)
tries := 0
for {
tries++
changed := p.pullerIteration(curIgnores)
if debug {
l.Debugln(p, "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 := p.model.RemoteLocalVersion(p.folder); 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(p, "adjusting curVer", lv)
curVer = lv
}
prevVer = curVer
if debug {
l.Debugln(p, "next pull in", nextPullIntv)
}
pullTimer.Reset(nextPullIntv)
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.Warnf("Folder %q isn't making progress - check logs for possible root cause. Pausing puller for %v.", p.folder, pauseIntv)
if debug {
l.Debugln(p, "next pull in", pauseIntv)
}
pullTimer.Reset(pauseIntv)
break
}
}
p.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 <-scanTimer.C:
if err := p.model.CheckFolderHealth(p.folder); err != nil {
l.Infoln("Skipping folder", p.folder, "scan due to folder error:", err)
rescheduleScan()
continue
}
if debug {
l.Debugln(p, "rescan")
}
if err := p.model.ScanFolder(p.folder); 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 CheckFolderHealth, though
// duplicate set is handled by setError.
p.setError(err)
rescheduleScan()
continue
}
if p.scanIntv > 0 {
rescheduleScan()
}
if !initialScanCompleted {
l.Infoln("Completed initial scan (rw) of folder", p.folder)
initialScanCompleted = true
}
}
}
}
func (p *rwFolder) Stop() {
close(p.stop)
}
func (p *rwFolder) String() string {
return fmt.Sprintf("rwFolder/%s@%p", p.folder, p)
}
// 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 (p *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()
if debug {
l.Debugln(p, "c", p.copiers, "p", p.pullers)
}
p.dbUpdates = make(chan protocol.FileInfo)
updateWg.Add(1)
go func() {
// dbUpdaterRoutine finishes when p.dbUpdates is closed
p.dbUpdaterRoutine()
updateWg.Done()
}()
for i := 0; i < p.copiers; i++ {
copyWg.Add(1)
go func() {
// copierRoutine finishes when copyChan is closed
p.copierRoutine(copyChan, pullChan, finisherChan)
copyWg.Done()
}()
}
for i := 0; i < p.pullers; i++ {
pullWg.Add(1)
go func() {
// pullerRoutine finishes when pullChan is closed
p.pullerRoutine(pullChan, finisherChan)
pullWg.Done()
}()
}
doneWg.Add(1)
// finisherRoutine finishes when finisherChan is closed
go func() {
p.finisherRoutine(finisherChan)
doneWg.Done()
}()
p.model.fmut.RLock()
folderFiles := p.model.folderFiles[p.folder]
p.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{}
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) {
// This is an ignored file. Skip it, continue iteration.
return true
}
if debug {
l.Debugln(p, "handling", file.Name)
}
switch {
case file.IsDeleted():
// A deleted file, directory or symlink
if file.IsDirectory() {
dirDeletions = append(dirDeletions, file)
} else {
fileDeletions[file.Name] = file
df, ok := p.model.CurrentFolderFile(p.folder, file.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 file.IsDirectory() && !file.IsSymlink():
// A new or changed directory
if debug {
l.Debugln("Creating directory", file.Name)
}
p.handleDir(file)
default:
// A new or changed file or symlink. This is the only case where we
// do stuff concurrently in the background
p.queue.Push(file.Name, file.Size(), file.Modified)
}
changed++
return true
})
// Reorder the file queue according to configuration
switch p.order {
case config.OrderRandom:
p.queue.Shuffle()
case config.OrderAlphabetic:
// The queue is already in alphabetic order.
case config.OrderSmallestFirst:
p.queue.SortSmallestFirst()
case config.OrderLargestFirst:
p.queue.SortLargestFirst()
case config.OrderOldestFirst:
p.queue.SortOldestFirst()
case config.OrderNewestFirst:
p.queue.SortOldestFirst()
}
// Process the file queue
nextFile:
for {
fileName, ok := p.queue.Pop()
if !ok {
break
}
f, ok := p.model.CurrentGlobalFile(p.folder, fileName)
if !ok {
// File is no longer in the index. Mark it as done and drop it.
p.queue.Done(fileName)
continue
}
// 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
// the global index changed while we were processing this iteration.
if !f.IsDeleted() && !f.IsSymlink() && !f.IsDirectory() {
key := string(f.Blocks[0].Hash)
for i, candidate := range buckets[key] {
if scanner.BlocksEqual(candidate.Blocks, f.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)
p.renameFile(desired, f)
p.queue.Done(fileName)
continue nextFile
}
}
}
// Not a rename or a symlink, deal with it.
p.handleFile(f, 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 {
if debug {
l.Debugln("Deleting file", file.Name)
}
p.deleteFile(file)
}
for i := range dirDeletions {
dir := dirDeletions[len(dirDeletions)-i-1]
if debug {
l.Debugln("Deleting dir", dir.Name)
}
p.deleteDir(dir)
}
// Wait for db updates to complete
close(p.dbUpdates)
updateWg.Wait()
return changed
}
// handleDir creates or updates the given directory
func (p *rwFolder) handleDir(file protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"type": "dir",
"action": "update",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"error": err,
"type": "dir",
"action": "update",
})
}()
realName := filepath.Join(p.dir, file.Name)
mode := os.FileMode(file.Flags & 0777)
if p.ignorePerms {
mode = 0755
}
if debug {
curFile, _ := p.model.CurrentFolderFile(p.folder, 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", p.folder, 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 || p.ignorePerms {
return err
}
return os.Chmod(path, mode)
}
if err = osutil.InWritableDir(mkdir, realName); err == nil {
p.dbUpdates <- file
} else {
l.Infof("Puller (folder %q, dir %q): %v", p.folder, 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", p.folder, 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 p.ignorePerms {
p.dbUpdates <- file
} else if err := os.Chmod(realName, mode); err == nil {
p.dbUpdates <- file
} else {
l.Infof("Puller (folder %q, dir %q): %v", p.folder, file.Name, err)
}
}
// deleteDir attempts to delete the given directory
func (p *rwFolder) deleteDir(file protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"type": "dir",
"action": "delete",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"error": err,
"type": "dir",
"action": "delete",
})
}()
realName := filepath.Join(p.dir, file.Name)
// Delete any temporary files lying around in the directory
dir, _ := os.Open(realName)
if dir != nil {
files, _ := dir.Readdirnames(-1)
for _, file := range files {
if defTempNamer.IsTemporary(file) {
osutil.InWritableDir(osutil.Remove, filepath.Join(realName, file))
}
}
}
err = osutil.InWritableDir(osutil.Remove, realName)
if err == nil || os.IsNotExist(err) {
p.dbUpdates <- file
} else {
l.Infof("Puller (folder %q, dir %q): delete: %v", p.folder, file.Name, err)
}
}
// deleteFile attempts to delete the given file
func (p *rwFolder) deleteFile(file protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"type": "file",
"action": "delete",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"error": err,
"type": "file",
"action": "delete",
})
}()
realName := filepath.Join(p.dir, file.Name)
cur, ok := p.model.CurrentFolderFile(p.folder, file.Name)
if ok && p.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(moveForConflict, realName)
} else if p.versioner != nil {
err = osutil.InWritableDir(p.versioner.Archive, realName)
} else {
err = osutil.InWritableDir(osutil.Remove, realName)
}
if err != nil && !os.IsNotExist(err) {
l.Infof("Puller (folder %q, file %q): delete: %v", p.folder, file.Name, err)
} else {
p.dbUpdates <- file
}
}
// renameFile attempts to rename an existing file to a destination
// and set the right attributes on it.
func (p *rwFolder) renameFile(source, target protocol.FileInfo) {
var err error
events.Default.Log(events.ItemStarted, map[string]interface{}{
"folder": p.folder,
"item": source.Name,
"type": "file",
"action": "delete",
})
events.Default.Log(events.ItemStarted, map[string]interface{}{
"folder": p.folder,
"item": target.Name,
"type": "file",
"action": "update",
})
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": source.Name,
"error": err,
"type": "file",
"action": "delete",
})
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": target.Name,
"error": err,
"type": "file",
"action": "update",
})
}()
if debug {
l.Debugln(p, "taking rename shortcut", source.Name, "->", target.Name)
}
from := filepath.Join(p.dir, source.Name)
to := filepath.Join(p.dir, target.Name)
if p.versioner != nil {
err = osutil.Copy(from, to)
if err == nil {
err = osutil.InWritableDir(p.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.
p.dbUpdates <- source
err = p.shortcutFile(target)
if err != nil {
l.Infof("Puller (folder %q, file %q): rename from %q metadata: %v", p.folder, target.Name, source.Name, err)
return
}
} 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", p.folder, target.Name, source.Name, err)
return
}
p.dbUpdates <- source
}
}
// handleFile queues the copies and pulls as necessary for a single new or
// changed file.
func (p *rwFolder) handleFile(file protocol.FileInfo, copyChan chan<- copyBlocksState, finisherChan chan<- *sharedPullerState) {
events.Default.Log(events.ItemStarted, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"type": "file",
"action": "update",
})
curFile, ok := p.model.CurrentFolderFile(p.folder, file.Name)
if ok && 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.
if debug {
l.Debugln(p, "taking shortcut on", file.Name)
}
p.queue.Done(file.Name)
var err error
if file.IsSymlink() {
err = p.shortcutSymlink(file)
} else {
err = p.shortcutFile(file)
}
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": file.Name,
"error": err,
"type": "file",
"action": "update",
})
return
}
scanner.PopulateOffsets(file.Blocks)
// Figure out the absolute filenames we need once and for all
tempName := filepath.Join(p.dir, defTempNamer.TempName(file.Name))
realName := filepath.Join(p.dir, file.Name)
reused := 0
var blocks []protocol.BlockInfo
// Check for an old temporary file which might have some blocks we could
// reuse.
tempBlocks, err := scanner.HashFile(tempName, protocol.BlockSize)
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 _, block := range file.Blocks {
_, ok := existingBlocks[block.String()]
if !ok {
blocks = append(blocks, block)
}
}
// The sharedpullerstate will know which flags to use when opening the
// temp file depending if we are reusing any blocks or not.
reused = len(file.Blocks) - len(blocks)
if 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
os.Remove(tempName)
}
} else {
blocks = file.Blocks
}
s := sharedPullerState{
file: file,
folder: p.folder,
tempName: tempName,
realName: realName,
copyTotal: len(blocks),
copyNeeded: len(blocks),
reused: reused,
ignorePerms: p.ignorePerms,
version: curFile.Version,
mut: sync.NewMutex(),
}
if debug {
l.Debugf("%v need file %s; copy %d, reused %v", p, 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 (p *rwFolder) shortcutFile(file protocol.FileInfo) (err error) {
realName := filepath.Join(p.dir, file.Name)
if !p.ignorePerms {
err = os.Chmod(realName, os.FileMode(file.Flags&0777))
if err != nil {
l.Infof("Puller (folder %q, file %q): shortcut: %v", p.folder, file.Name, err)
return
}
}
t := time.Unix(file.Modified, 0)
err = os.Chtimes(realName, t, t)
if err != nil {
if p.lenientMtimes {
err = nil
// We accept the failure with a warning here and allow the sync to
// continue. We'll sync the new mtime back to the other devices later.
// If they have the same problem & setting, we might never get in
// sync.
l.Infof("Puller (folder %q, file %q): shortcut: %v (continuing anyway as requested)", p.folder, file.Name, err)
} else {
l.Infof("Puller (folder %q, file %q): shortcut: %v", p.folder, file.Name, err)
return
}
}
// This may have been a conflict. We should merge the version vectors so
// that our clock doesn't move backwards.
if cur, ok := p.model.CurrentFolderFile(p.folder, file.Name); ok {
file.Version = file.Version.Merge(cur.Version)
}
p.dbUpdates <- file
return
}
// shortcutSymlink changes the symlinks type if necessary.
func (p *rwFolder) shortcutSymlink(file protocol.FileInfo) (err error) {
err = symlinks.ChangeType(filepath.Join(p.dir, file.Name), file.Flags)
if err == nil {
p.dbUpdates <- file
} else {
l.Infof("Puller (folder %q, file %q): symlink shortcut: %v", p.folder, 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 (p *rwFolder) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBlockState, out chan<- *sharedPullerState) {
buf := make([]byte, protocol.BlockSize)
for state := range in {
if p.progressEmitter != nil {
p.progressEmitter.Register(state.sharedPullerState)
}
dstFd, err := state.tempFile()
if err != nil {
// Nothing more to do for this failed file (the error was logged
// when it happened)
out <- state.sharedPullerState
continue
}
folderRoots := make(map[string]string)
p.model.fmut.RLock()
for folder, cfg := range p.model.folderCfgs {
folderRoots[folder] = cfg.Path()
}
p.model.fmut.RUnlock()
for _, block := range state.blocks {
buf = buf[:int(block.Size)]
found := p.model.finder.Iterate(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 {
if debug {
l.Debugf("Finder block mismatch in %s:%s:%d expected %q got %q", folder, file, index, block.Hash, hash)
}
err = p.model.finder.Fix(folder, file, index, block.Hash, hash)
if err != nil {
l.Warnln("finder fix:", err)
}
} else if debug {
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()
}
}
out <- state.sharedPullerState
}
}
func (p *rwFolder) pullerRoutine(in <-chan pullBlockState, out chan<- *sharedPullerState) {
for state := range in {
if state.failed() != nil {
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 {
continue
}
var lastError error
potentialDevices := p.model.Availability(p.folder, state.file.Name)
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 := activity.leastBusy(potentialDevices)
if selected == (protocol.DeviceID{}) {
if lastError != nil {
state.fail("pull", lastError)
} else {
state.fail("pull", errNoDevice)
}
break
}
potentialDevices = removeDevice(potentialDevices, 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 := p.model.requestGlobal(selected, p.folder, state.file.Name, state.block.Offset, int(state.block.Size), state.block.Hash, 0, nil)
activity.done(selected)
if lastError != nil {
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 {
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()
}
break
}
out <- state.sharedPullerState
}
}
func (p *rwFolder) performFinish(state *sharedPullerState) {
var err error
defer func() {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": state.file.Name,
"error": err,
"type": "file",
"action": "update",
})
}()
// Set the correct permission bits on the new file
if !p.ignorePerms {
err = os.Chmod(state.tempName, os.FileMode(state.file.Flags&0777))
if err != nil {
l.Warnln("Puller: final:", err)
return
}
}
// Set the correct timestamp on the new file
t := time.Unix(state.file.Modified, 0)
err = os.Chtimes(state.tempName, t, t)
if err != nil {
if p.lenientMtimes {
// We accept the failure with a warning here and allow the sync to
// continue. We'll sync the new mtime back to the other devices later.
// If they have the same problem & setting, we might never get in
// sync.
l.Infof("Puller (folder %q, file %q): final: %v (continuing anyway as requested)", p.folder, state.file.Name, err)
} else {
l.Warnln("Puller: final:", err)
return
}
}
if p.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)
err = osutil.InWritableDir(moveForConflict, state.realName)
} else if p.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.
err = p.versioner.Archive(state.realName)
} else {
err = nil
}
if err != nil {
l.Warnln("Puller: final:", err)
return
}
// If the target path is a symlink or a directory, we cannot copy
// over it, hence remove it before proceeding.
stat, err := osutil.Lstat(state.realName)
if err == nil && (stat.IsDir() || stat.Mode()&os.ModeSymlink != 0) {
osutil.InWritableDir(osutil.Remove, state.realName)
}
// Replace the original content with the new one
err = osutil.Rename(state.tempName, state.realName)
if err != nil {
l.Warnln("Puller: final:", err)
return
}
// 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 {
l.Warnln("Puller: final: reading symlink:", err)
return
}
// Remove the file, and replace it with a symlink.
err = osutil.InWritableDir(func(path string) error {
os.Remove(path)
return symlinks.Create(path, string(content), state.file.Flags)
}, state.realName)
if err != nil {
l.Warnln("Puller: final: creating symlink:", err)
return
}
}
// Record the updated file in the index
p.dbUpdates <- state.file
}
func (p *rwFolder) finisherRoutine(in <-chan *sharedPullerState) {
for state := range in {
if closed, err := state.finalClose(); closed {
if debug {
l.Debugln(p, "closing", state.file.Name)
}
if err != nil {
l.Warnln("Puller: final:", err)
continue
}
p.queue.Done(state.file.Name)
if state.failed() == nil {
p.performFinish(state)
} else {
events.Default.Log(events.ItemFinished, map[string]interface{}{
"folder": p.folder,
"item": state.file.Name,
"error": state.failed(),
"type": "file",
"action": "update",
})
}
p.model.receivedFile(p.folder, state.file.Name)
if p.progressEmitter != nil {
p.progressEmitter.Deregister(state)
}
}
}
}
// Moves the given filename to the front of the job queue
func (p *rwFolder) BringToFront(filename string) {
p.queue.BringToFront(filename)
}
func (p *rwFolder) Jobs() ([]string, []string) {
return p.queue.Jobs()
}
// dbUpdaterRoutine aggregates db updates and commits them in batches no
// larger than 1000 items, and no more delayed than 2 seconds.
func (p *rwFolder) dbUpdaterRoutine() {
const (
maxBatchSize = 1000
maxBatchTime = 2 * time.Second
)
batch := make([]protocol.FileInfo, 0, maxBatchSize)
tick := time.NewTicker(maxBatchTime)
defer tick.Stop()
loop:
for {
select {
case file, ok := <-p.dbUpdates:
if !ok {
break loop
}
file.LocalVersion = 0
batch = append(batch, file)
if len(batch) == maxBatchSize {
p.model.updateLocals(p.folder, batch)
batch = batch[:0]
}
case <-tick.C:
if len(batch) > 0 {
p.model.updateLocals(p.folder, batch)
batch = batch[:0]
}
}
}
if len(batch) > 0 {
p.model.updateLocals(p.folder, batch)
}
}
func (p *rwFolder) inConflict(current, replacement protocol.Vector) bool {
if current.Concurrent(replacement) {
// Obvious case
return true
}
if replacement.Counter(p.shortID) > current.Counter(p.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 invalidateFolder(cfg *config.Configuration, folderID string, err error) {
for i := range cfg.Folders {
folder := &cfg.Folders[i]
if folder.ID == folderID {
folder.Invalid = err.Error()
return
}
}
}
func removeDevice(devices []protocol.DeviceID, device protocol.DeviceID) []protocol.DeviceID {
for i := range devices {
if devices[i] == device {
devices[i] = devices[len(devices)-1]
return devices[:len(devices)-1]
}
}
return devices
}
func moveForConflict(name string) error {
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.
return nil
}
return err
}