syncthing/model/puller.go
2014-05-20 20:27:21 +02:00

631 lines
14 KiB
Go

package model
import (
"bytes"
"errors"
"os"
"path/filepath"
"time"
"github.com/calmh/syncthing/buffers"
"github.com/calmh/syncthing/cid"
"github.com/calmh/syncthing/config"
"github.com/calmh/syncthing/protocol"
"github.com/calmh/syncthing/scanner"
)
type requestResult struct {
node string
file scanner.File
filepath string // full filepath name
offset int64
data []byte
err error
}
type openFile struct {
filepath string // full filepath name
temp string // temporary filename
availability uint64 // availability bitset
file *os.File
err error // error when opening or writing to file, all following operations are cancelled
outstanding int // number of requests we still have outstanding
done bool // we have sent all requests for this file
}
type activityMap map[string]int
func (m activityMap) leastBusyNode(availability uint64, cm *cid.Map) string {
var low int = 2<<30 - 1
var selected string
for _, node := range cm.Names() {
id := cm.Get(node)
if id == cid.LocalID {
continue
}
usage := m[node]
if availability&(1<<id) != 0 {
if usage < low {
low = usage
selected = node
}
}
}
m[selected]++
return selected
}
func (m activityMap) decrease(node string) {
m[node]--
}
var errNoNode = errors.New("no available source node")
type puller struct {
cfg *config.Configuration
repo string
dir string
bq *blockQueue
model *Model
oustandingPerNode activityMap
openFiles map[string]openFile
requestSlots chan bool
blocks chan bqBlock
requestResults chan requestResult
}
func newPuller(repo, dir string, model *Model, slots int, cfg *config.Configuration) *puller {
p := &puller{
cfg: cfg,
repo: repo,
dir: dir,
bq: newBlockQueue(),
model: model,
oustandingPerNode: make(activityMap),
openFiles: make(map[string]openFile),
requestSlots: make(chan bool, slots),
blocks: make(chan bqBlock),
requestResults: make(chan requestResult),
}
if slots > 0 {
// Read/write
for i := 0; i < slots; i++ {
p.requestSlots <- true
}
if debug {
l.Debugf("starting puller; repo %q dir %q slots %d", repo, dir, slots)
}
go p.run()
} else {
// Read only
if debug {
l.Debugf("starting puller; repo %q dir %q (read only)", repo, dir)
}
go p.runRO()
}
return p
}
func (p *puller) run() {
go func() {
// fill blocks queue when there are free slots
for {
<-p.requestSlots
b := p.bq.get()
if debug {
l.Debugf("filler: queueing %q / %q offset %d copy %d", p.repo, b.file.Name, b.block.Offset, len(b.copy))
}
p.blocks <- b
}
}()
walkTicker := time.Tick(time.Duration(p.cfg.Options.RescanIntervalS) * time.Second)
timeout := time.Tick(5 * time.Second)
changed := true
for {
// Run the pulling loop as long as there are blocks to fetch
pull:
for {
select {
case res := <-p.requestResults:
p.model.setState(p.repo, RepoSyncing)
changed = true
p.requestSlots <- true
p.handleRequestResult(res)
case b := <-p.blocks:
p.model.setState(p.repo, RepoSyncing)
changed = true
if p.handleBlock(b) {
// Block was fully handled, free up the slot
p.requestSlots <- true
}
case <-timeout:
if len(p.openFiles) == 0 && p.bq.empty() {
// Nothing more to do for the moment
break pull
}
if debug {
l.Debugf("%q: idle but have %d open files", p.repo, len(p.openFiles))
i := 5
for _, f := range p.openFiles {
l.Debugf(" %v", f)
i--
if i == 0 {
break
}
}
}
}
}
if changed {
p.model.setState(p.repo, RepoCleaning)
p.fixupDirectories()
changed = false
}
p.model.setState(p.repo, RepoIdle)
// Do a rescan if it's time for it
select {
case <-walkTicker:
if debug {
l.Debugf("%q: time for rescan", p.repo)
}
err := p.model.ScanRepo(p.repo)
if err != nil {
invalidateRepo(p.cfg, p.repo, err)
return
}
default:
}
// Queue more blocks to fetch, if any
p.queueNeededBlocks()
}
}
func (p *puller) runRO() {
walkTicker := time.Tick(time.Duration(p.cfg.Options.RescanIntervalS) * time.Second)
for _ = range walkTicker {
if debug {
l.Debugf("%q: time for rescan", p.repo)
}
err := p.model.ScanRepo(p.repo)
if err != nil {
invalidateRepo(p.cfg, p.repo, err)
return
}
}
}
func (p *puller) fixupDirectories() {
var deleteDirs []string
var changed = 0
var walkFn = func(path string, info os.FileInfo, err error) error {
if !info.IsDir() {
return nil
}
rn, err := filepath.Rel(p.dir, path)
if err != nil {
return nil
}
if rn == "." {
return nil
}
cur := p.model.CurrentRepoFile(p.repo, rn)
if cur.Name != rn {
// No matching dir in current list; weird
if debug {
l.Debugf("missing dir: %s; %v", rn, cur)
}
return nil
}
if cur.Flags&protocol.FlagDeleted != 0 {
if debug {
l.Debugf("queue delete dir: %v", cur)
}
// We queue the directories to delete since we walk the
// tree in depth first order and need to remove the
// directories in the opposite order.
deleteDirs = append(deleteDirs, path)
return nil
}
if cur.Flags&uint32(os.ModePerm) != uint32(info.Mode()&os.ModePerm) {
err := os.Chmod(path, os.FileMode(cur.Flags)&os.ModePerm)
if err != nil {
l.Warnln("Restoring folder flags: %q: %v", path, err)
} else {
changed++
if debug {
l.Debugf("restored dir flags: %o -> %v", info.Mode()&os.ModePerm, cur)
}
}
}
if cur.Modified != info.ModTime().Unix() {
t := time.Unix(cur.Modified, 0)
err := os.Chtimes(path, t, t)
if err != nil {
l.Warnln("Restoring folder modtime: %q: %v", path, err)
} else {
changed++
if debug {
l.Debugf("restored dir modtime: %d -> %v", info.ModTime().Unix(), cur)
}
}
}
return nil
}
for {
deleteDirs = nil
changed = 0
filepath.Walk(p.dir, walkFn)
var deleted = 0
// Delete any queued directories
for i := len(deleteDirs) - 1; i >= 0; i-- {
dir := deleteDirs[i]
if debug {
l.Debugln("delete dir:", dir)
}
err := os.Remove(dir)
if err != nil {
l.Warnln(err)
} else {
deleted++
}
}
if debug {
l.Debugf("changed %d, deleted %d dirs", changed, deleted)
}
if changed+deleted == 0 {
return
}
}
}
func (p *puller) handleRequestResult(res requestResult) {
p.oustandingPerNode.decrease(res.node)
f := res.file
of, ok := p.openFiles[f.Name]
if !ok || of.err != nil {
// no entry in openFiles means there was an error and we've cancelled the operation
return
}
_, of.err = of.file.WriteAt(res.data, res.offset)
buffers.Put(res.data)
of.outstanding--
p.openFiles[f.Name] = of
if debug {
l.Debugf("pull: wrote %q / %q offset %d outstanding %d done %v", p.repo, f.Name, res.offset, of.outstanding, of.done)
}
if of.done && of.outstanding == 0 {
p.closeFile(f)
}
}
// handleBlock fulfills the block request by copying, ignoring or fetching
// from the network. Returns true if the block was fully handled
// synchronously, i.e. if the slot can be reused.
func (p *puller) handleBlock(b bqBlock) bool {
f := b.file
// For directories, making sure they exist is enough.
// Deleted directories we mark as handled and delete later.
if f.Flags&protocol.FlagDirectory != 0 {
if f.Flags&protocol.FlagDeleted == 0 {
path := filepath.Join(p.dir, f.Name)
_, err := os.Stat(path)
if err != nil && os.IsNotExist(err) {
if debug {
l.Debugf("create dir: %v", f)
}
err = os.MkdirAll(path, 0777)
if err != nil {
l.Warnf("Create folder: %q: %v", path, err)
}
}
} else if debug {
l.Debugf("ignore delete dir: %v", f)
}
p.model.updateLocal(p.repo, f)
return true
}
of, ok := p.openFiles[f.Name]
of.done = b.last
if !ok {
if debug {
l.Debugf("pull: %q: opening file %q", p.repo, f.Name)
}
of.availability = uint64(p.model.repoFiles[p.repo].Availability(f.Name))
of.filepath = filepath.Join(p.dir, f.Name)
of.temp = filepath.Join(p.dir, defTempNamer.TempName(f.Name))
dirName := filepath.Dir(of.filepath)
_, err := os.Stat(dirName)
if err != nil {
err = os.MkdirAll(dirName, 0777)
}
if err != nil {
l.Debugf("pull: error: %q / %q: %v", p.repo, f.Name, err)
}
of.file, of.err = os.Create(of.temp)
if of.err != nil {
if debug {
l.Debugf("pull: error: %q / %q: %v", p.repo, f.Name, of.err)
}
if !b.last {
p.openFiles[f.Name] = of
}
return true
}
defTempNamer.Hide(of.temp)
}
if of.err != nil {
// We have already failed this file.
if debug {
l.Debugf("pull: error: %q / %q has already failed: %v", p.repo, f.Name, of.err)
}
if b.last {
delete(p.openFiles, f.Name)
}
return true
}
p.openFiles[f.Name] = of
switch {
case len(b.copy) > 0:
p.handleCopyBlock(b)
return true
case b.block.Size > 0:
return p.handleRequestBlock(b)
default:
p.handleEmptyBlock(b)
return true
}
}
func (p *puller) handleCopyBlock(b bqBlock) {
// We have blocks to copy from the existing file
f := b.file
of := p.openFiles[f.Name]
if debug {
l.Debugf("pull: copying %d blocks for %q / %q", len(b.copy), p.repo, f.Name)
}
var exfd *os.File
exfd, of.err = os.Open(of.filepath)
if of.err != nil {
if debug {
l.Debugf("pull: error: %q / %q: %v", p.repo, f.Name, of.err)
}
of.file.Close()
of.file = nil
p.openFiles[f.Name] = of
return
}
defer exfd.Close()
for _, b := range b.copy {
bs := buffers.Get(int(b.Size))
_, of.err = exfd.ReadAt(bs, b.Offset)
if of.err == nil {
_, of.err = of.file.WriteAt(bs, b.Offset)
}
buffers.Put(bs)
if of.err != nil {
if debug {
l.Debugf("pull: error: %q / %q: %v", p.repo, f.Name, of.err)
}
exfd.Close()
of.file.Close()
of.file = nil
p.openFiles[f.Name] = of
return
}
}
}
// handleRequestBlock tries to pull a block from the network. Returns true if
// the block could _not_ be fetched (i.e. it was fully handled, matching the
// return criteria of handleBlock)
func (p *puller) handleRequestBlock(b bqBlock) bool {
f := b.file
of, ok := p.openFiles[f.Name]
if !ok {
panic("bug: request for non-open file")
}
node := p.oustandingPerNode.leastBusyNode(of.availability, p.model.cm)
if len(node) == 0 {
of.err = errNoNode
if of.file != nil {
of.file.Close()
of.file = nil
os.Remove(of.temp)
}
if b.last {
delete(p.openFiles, f.Name)
} else {
p.openFiles[f.Name] = of
}
return true
}
of.outstanding++
p.openFiles[f.Name] = of
go func(node string, b bqBlock) {
if debug {
l.Debugf("pull: requesting %q / %q offset %d size %d from %q outstanding %d", p.repo, f.Name, b.block.Offset, b.block.Size, node, of.outstanding)
}
bs, err := p.model.requestGlobal(node, p.repo, f.Name, b.block.Offset, int(b.block.Size), nil)
p.requestResults <- requestResult{
node: node,
file: f,
filepath: of.filepath,
offset: b.block.Offset,
data: bs,
err: err,
}
}(node, b)
return false
}
func (p *puller) handleEmptyBlock(b bqBlock) {
f := b.file
of := p.openFiles[f.Name]
if b.last {
if of.err == nil {
of.file.Close()
}
}
if f.Flags&protocol.FlagDeleted != 0 {
if debug {
l.Debugf("pull: delete %q", f.Name)
}
os.Remove(of.temp)
os.Chmod(of.filepath, 0666)
if err := os.Remove(of.filepath); err == nil || os.IsNotExist(err) {
p.model.updateLocal(p.repo, f)
}
} else {
if debug {
l.Debugf("pull: no blocks to fetch and nothing to copy for %q / %q", p.repo, f.Name)
}
t := time.Unix(f.Modified, 0)
if os.Chtimes(of.temp, t, t) != nil {
delete(p.openFiles, f.Name)
return
}
if os.Chmod(of.temp, os.FileMode(f.Flags&0777)) != nil {
delete(p.openFiles, f.Name)
return
}
defTempNamer.Show(of.temp)
if Rename(of.temp, of.filepath) == nil {
p.model.updateLocal(p.repo, f)
}
}
delete(p.openFiles, f.Name)
}
func (p *puller) queueNeededBlocks() {
queued := 0
for _, f := range p.model.NeedFilesRepo(p.repo) {
lf := p.model.CurrentRepoFile(p.repo, f.Name)
have, need := scanner.BlockDiff(lf.Blocks, f.Blocks)
if debug {
l.Debugf("need:\n local: %v\n global: %v\n haveBlocks: %v\n needBlocks: %v", lf, f, have, need)
}
queued++
p.bq.put(bqAdd{
file: f,
have: have,
need: need,
})
}
if debug && queued > 0 {
l.Debugf("%q: queued %d blocks", p.repo, queued)
}
}
func (p *puller) closeFile(f scanner.File) {
if debug {
l.Debugf("pull: closing %q / %q", p.repo, f.Name)
}
of := p.openFiles[f.Name]
of.file.Close()
defer os.Remove(of.temp)
delete(p.openFiles, f.Name)
fd, err := os.Open(of.temp)
if err != nil {
if debug {
l.Debugf("pull: error: %q / %q: %v", p.repo, f.Name, err)
}
return
}
hb, _ := scanner.Blocks(fd, scanner.StandardBlockSize)
fd.Close()
if l0, l1 := len(hb), len(f.Blocks); l0 != l1 {
if debug {
l.Debugf("pull: %q / %q: nblocks %d != %d", p.repo, f.Name, l0, l1)
}
return
}
for i := range hb {
if bytes.Compare(hb[i].Hash, f.Blocks[i].Hash) != 0 {
l.Debugf("pull: %q / %q: block %d hash mismatch", p.repo, f.Name, i)
return
}
}
t := time.Unix(f.Modified, 0)
os.Chtimes(of.temp, t, t)
os.Chmod(of.temp, os.FileMode(f.Flags&0777))
defTempNamer.Show(of.temp)
if debug {
l.Debugf("pull: rename %q / %q: %q", p.repo, f.Name, of.filepath)
}
if err := Rename(of.temp, of.filepath); err == nil {
p.model.updateLocal(p.repo, f)
} else {
l.Debugf("pull: error: %q / %q: %v", p.repo, f.Name, err)
}
}
func invalidateRepo(cfg *config.Configuration, repoID string, err error) {
for i := range cfg.Repositories {
repo := &cfg.Repositories[i]
if repo.ID == repoID {
repo.Invalid = err.Error()
return
}
}
}