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Hash blocks after receipt, try multiple peers (fixes #1166)

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This commit is contained in:
Audrius Butkevicius
2014-12-28 23:11:32 +00:00
parent 46343f2f9e
commit 5ac01a3af4
5 changed files with 90 additions and 71 deletions
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2
internal/model/model.go
View File

@@ -1369,7 +1369,7 @@ func (m *Model) RemoteLocalVersion(folder string) uint64 {
func (m *Model) availability(folder, file string) []protocol.DeviceID {
// Acquire this lock first, as the value returned from foldersFiles can
// gen heavily modified on Close()
// get heavily modified on Close()
m.pmut.RLock()
defer m.pmut.RUnlock()

128
internal/model/puller.go
View File

@@ -16,8 +16,6 @@
package model
import (
"bytes"
"crypto/sha256"
"errors"
"fmt"
"io/ioutil"
@@ -158,16 +156,10 @@ loop:
}
p.model.setState(p.folder, FolderSyncing)
tries := 0
checksum := false
for {
tries++
// Last resort mode, to get around corrupt/invalid block maps.
if tries == 10 {
l.Infoln("Desperation mode ON")
checksum = true
}
changed := p.pullerIteration(checksum, curIgnores)
changed := p.pullerIteration(curIgnores)
if debug {
l.Debugln(p, "changed", changed)
}
@@ -255,7 +247,7 @@ func (p *Puller) String() string {
// 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 *Puller) pullerIteration(checksum bool, ignores *ignore.Matcher) int {
func (p *Puller) pullerIteration(ignores *ignore.Matcher) int {
pullChan := make(chan pullBlockState)
copyChan := make(chan copyBlocksState)
finisherChan := make(chan *sharedPullerState)
@@ -272,7 +264,7 @@ func (p *Puller) pullerIteration(checksum bool, ignores *ignore.Matcher) int {
copyWg.Add(1)
go func() {
// copierRoutine finishes when copyChan is closed
p.copierRoutine(copyChan, pullChan, finisherChan, checksum)
p.copierRoutine(copyChan, pullChan, finisherChan)
copyWg.Done()
}()
}
@@ -613,7 +605,7 @@ func (p *Puller) shortcutSymlink(curFile, file protocol.FileInfo) {
// copierRoutine reads copierStates until the in channel closes and performs
// the relevant copies when possible, or passes it to the puller routine.
func (p *Puller) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBlockState, out chan<- *sharedPullerState, checksum bool) {
func (p *Puller) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBlockState, out chan<- *sharedPullerState) {
buf := make([]byte, protocol.BlockSize)
nextFile:
@@ -649,7 +641,6 @@ nextFile:
}
p.model.fmut.RUnlock()
hasher := sha256.New()
for _, block := range state.blocks {
buf = buf[:int(block.Size)]
found := p.model.finder.Iterate(block.Hash, func(folder, file string, index uint32) bool {
@@ -673,12 +664,9 @@ nextFile:
return false
}
// Only done on second to last puller attempt
if checksum {
hasher.Write(buf)
hash := hasher.Sum(nil)
hasher.Reset()
if !bytes.Equal(hash, block.Hash) {
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)
}
@@ -686,8 +674,10 @@ nextFile:
if err != nil {
l.Warnln("finder fix:", err)
}
return false
} else if debug {
l.Debugln("Finder failed to verify buffer", err)
}
return false
}
_, err = dstFd.WriteAt(buf, block.Offset)
@@ -722,20 +712,9 @@ nextFile:
}
func (p *Puller) pullerRoutine(in <-chan pullBlockState, out chan<- *sharedPullerState) {
nextBlock:
for state := range in {
if state.failed() != nil {
continue nextBlock
}
// 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).
potentialDevices := p.model.availability(p.folder, state.file.Name)
selected := activity.leastBusy(potentialDevices)
if selected == (protocol.DeviceID{}) {
state.earlyClose("pull", errNoDevice)
continue nextBlock
continue
}
// Get an fd to the temporary file. Tehcnically we don't need it until
@@ -743,45 +722,58 @@ nextBlock:
// no point in issuing the request to the network.
fd, err := state.tempFile()
if err != nil {
continue nextBlock
continue
}
// 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, err := p.model.requestGlobal(selected, p.folder, state.file.Name, state.block.Offset, int(state.block.Size), state.block.Hash)
activity.done(selected)
if err != nil {
state.earlyClose("pull", err)
continue nextBlock
}
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.earlyClose("pull", lastError)
} else {
state.earlyClose("pull", errNoDevice)
}
break
}
// Save the block data we got from the cluster
_, err = fd.WriteAt(buf, state.block.Offset)
if err != nil {
state.earlyClose("save", err)
continue nextBlock
}
potentialDevices = removeDevice(potentialDevices, selected)
state.pullDone()
out <- state.sharedPullerState
// 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)
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.earlyClose("save", err)
} else {
state.pullDone()
out <- state.sharedPullerState
}
break
}
}
}
func (p *Puller) performFinish(state *sharedPullerState) {
// Verify the file against expected hashes
fd, err := os.Open(state.tempName)
if err != nil {
l.Warnln("puller: final:", err)
return
}
err = scanner.Verify(fd, protocol.BlockSize, state.file.Blocks)
fd.Close()
if err != nil {
l.Infoln("puller:", state.file.Name, err, "(file changed during pull?)")
return
}
var err error
// Set the correct permission bits on the new file
if !p.ignorePerms {
err = os.Chmod(state.tempName, os.FileMode(state.file.Flags&0777))
@@ -893,3 +885,13 @@ func invalidateFolder(cfg *config.Configuration, folderID string, err error) {
}
}
}
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
}

11
internal/model/puller_test.go
View File

@@ -221,7 +221,7 @@ func TestCopierFinder(t *testing.T) {
finisherChan := make(chan *sharedPullerState, 1)
// Run a single fetcher routine
go p.copierRoutine(copyChan, pullChan, finisherChan, false)
go p.copierRoutine(copyChan, pullChan, finisherChan)
p.handleFile(requiredFile, copyChan, finisherChan)
@@ -317,9 +317,8 @@ func TestCopierCleanup(t *testing.T) {
}
}
// On the 10th iteration, we start hashing the content which we receive by
// following blockfinder's instructions. Make sure that the copier routine
// hashes the content when asked, and pulls if it fails to find the block.
// Make sure that the copier routine hashes the content when asked, and pulls
// if it fails to find the block.
func TestLastResortPulling(t *testing.T) {
fcfg := config.FolderConfiguration{ID: "default", Path: "testdata"}
cfg := config.Configuration{Folders: []config.FolderConfiguration{fcfg}}
@@ -361,8 +360,8 @@ func TestLastResortPulling(t *testing.T) {
pullChan := make(chan pullBlockState, 1)
finisherChan := make(chan *sharedPullerState, 1)
// Run a single copier routine with checksumming enabled
go p.copierRoutine(copyChan, pullChan, finisherChan, true)
// Run a single copier routine
go p.copierRoutine(copyChan, pullChan, finisherChan)
p.handleFile(file, copyChan, finisherChan)

18
internal/scanner/blocks.go
View File

@@ -130,6 +130,24 @@ func Verify(r io.Reader, blocksize int, blocks []protocol.BlockInfo) error {
return nil
}
func VerifyBuffer(buf []byte, block protocol.BlockInfo) ([]byte, error) {
if len(buf) != int(block.Size) {
return nil, fmt.Errorf("length mismatch %d != %d", len(buf), block.Size)
}
hf := sha256.New()
_, err := hf.Write(buf)
if err != nil {
return nil, err
}
hash := hf.Sum(nil)
if !bytes.Equal(hash, block.Hash) {
return hash, fmt.Errorf("hash mismatch %x != %x", hash, block.Hash)
}
return hash, nil
}
// BlockEqual returns whether two slices of blocks are exactly the same hash
// and index pair wise.
func BlocksEqual(src, tgt []protocol.BlockInfo) bool {