func (p *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 p.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()
out <- state.sharedPullerState
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 {
l.Debugln("request:", p.folder, 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:", p.folder, 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()
}
break
}
out <- state.sharedPullerState
}
}
// 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 {
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 p.progressEmitter != nil {
p.progressEmitter.Register(state.sharedPullerState)
}
folderRoots := make(map[string]string)
var folders []string
p.model.fmut.RLock()
for folder, cfg := range p.model.folderCfgs {
folderRoots[folder] = cfg.Path()
folders = append(folders, folder)
}
p.model.fmut.RUnlock()
for _, block := range state.blocks {
if p.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 := p.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 = p.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()
}
}
out <- state.sharedPullerState
}
}