[Bug] goroutine leak in layer store when apply diff with an invalid image tarball

[zvier]

A goroutine leak is occurred when imports an invalid image tarball. The invalid image tarball can be made as flows:

touch test.tar
echo 'aaa' >> test.tar

Then use the invalid image tarball as an base image import to the storage and it will return error with 'error adding layer with blob'. But a goroutine is leak at this time.

With go pprof tool(net/http/pprof), we trace the goroutine was blok in github.com/vbatts/tar-split/archive/tar.(*Reader).readHeader .

func (tr *Reader) readHeader() (*Header, *block, error) {
    n, err := io.ReadFull(tr.r, tr.blk[:])   // This is the block point
    ...
}

Because the io.ReadFull will call tr.r.Read() and the tr.r is the read endpoint of a pip which create in NewLogger.

// github.com/containers/storage/pkg/tarlog/tarlogger.go
 func NewLogger(logger func(*tar.Header)) (io.WriteCloser, error) {
      reader, writer := io.Pipe()
      t := &tarLogger{
          writer:     writer,
          closeMutex: new(sync.Mutex),
          closed:     false,
      }
      tr := tar.NewReader(reader)
      ...

So, if the write endpoint of the pip never close, the readHeader will block and lead a goroutine leak. Since io.Pipe is in-memory, close with an defer clause is safety after it created.