remove all hashing on the download path

server/peer/server.go

@@ -274,7 +274,7 @@ func (s *Server) handleCompositeRequest(data []byte) ([]byte, error) {
 			return nil, err
 		} else {
 			response.IncomingBlob = incomingBlob{
-				BlobHash: reflector.BlobHash(blob),
+				BlobHash: request.RequestedBlob,
 				Length:   len(blob),
 			}
 			metrics.MtrOutBytesTcp.Add(float64(len(blob)))

store/disk.go

@@ -2,9 +2,6 @@ package store
 
 import (
 	"bytes"
-	"crypto/sha512"
-	"encoding/hex"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
@@ -18,8 +15,6 @@ import (
 	"github.com/lbryio/lbry.go/v2/stream"
 
 	"github.com/brk0v/directio"
-	log "github.com/sirupsen/logrus"
-	"go.uber.org/atomic"
 )
 
 // DiskStore stores blobs on a local disk
@@ -31,12 +26,8 @@ type DiskStore struct {
 
 	// true if initOnce ran, false otherwise
 	initialized bool
-
-	concurrentChecks atomic.Int32
 }
 
-const maxConcurrentChecks = 30
-
 // NewDiskStore returns an initialized file disk store pointer.
 func NewDiskStore(dir string, prefixLength int) *DiskStore {
 	return &DiskStore{
@@ -82,25 +73,6 @@ func (d *DiskStore) Get(hash string) (stream.Blob, shared.BlobTrace, error) {
 		}
 		return nil, shared.NewBlobTrace(time.Since(start), d.Name()), errors.Err(err)
 	}
-
-	// this is a rather poor yet effective way of throttling how many blobs can be checked concurrently
-	// poor because there is a possible race condition between the check and the actual +1
-	if d.concurrentChecks.Load() < maxConcurrentChecks {
-		d.concurrentChecks.Add(1)
-		defer d.concurrentChecks.Sub(1)
-		hashBytes := sha512.Sum384(blob)
-		readHash := hex.EncodeToString(hashBytes[:])
-		if hash != readHash {
-			message := fmt.Sprintf("[%s] found a broken blob while reading from disk. Actual hash: %s", hash, readHash)
-			log.Errorf("%s", message)
-			err := d.Delete(hash)
-			if err != nil {
-				return nil, shared.NewBlobTrace(time.Since(start), d.Name()), err
-			}
-			return nil, shared.NewBlobTrace(time.Since(start), d.Name()), errors.Err(message)
-		}
-	}
-
 	return blob, shared.NewBlobTrace(time.Since(start), d.Name()), nil
 }