On torrentfs read, read the full requested buffer and don't return early

diff --git a/fs/torrentfs.go b/fs/torrentfs.go
index a8d18cf1fd72cee50f8da4e2a4d4f948eef94ba8..4bdcd781446fc4866d46375b2cc1a8983bb219d1 100644 (file)
--- a/fs/torrentfs.go
+++ b/fs/torrentfs.go
@@ -2,6 +2,7 @@ package torrentfs
 
 import (
        "expvar"
+       "fmt"
        "log"
        "os"
        "strings"
@@ -72,6 +73,35 @@ func (n *node) fsPath() string {
        return "/" + strings.Join(append([]string{n.metadata.Name}, n.path...), "/")
 }
 
+func blockingRead(fs *torrentFS, ih torrent.InfoHash, off int64, p []byte, intr fusefs.Intr) (n int, err fuse.Error) {
+       dataWaiter := fs.Client.DataWaiter(ih, off)
+       select {
+       case <-dataWaiter:
+       case <-fs.destroyed:
+               err = fuse.EIO
+               return
+       case <-intr:
+               err = fuse.EINTR
+               return
+       }
+       n, err = fs.Client.TorrentReadAt(ih, off, p)
+       return
+}
+
+func readFull(fs *torrentFS, ih torrent.InfoHash, off int64, p []byte, intr fusefs.Intr) (n int, err fuse.Error) {
+       for len(p) != 0 {
+               var nn int
+               nn, err = blockingRead(fs, ih, off, p, intr)
+               if err != nil {
+                       break
+               }
+               n += nn
+               off += int64(nn)
+               p = p[nn:]
+       }
+       return
+}
+
 func (fn fileNode) Read(req *fuse.ReadRequest, resp *fuse.ReadResponse, intr fusefs.Intr) fuse.Error {
        torrentfsReadRequests.Add(1)
        started := time.Now()
@@ -104,31 +134,14 @@ func (fn fileNode) Read(req *fuse.ReadRequest, resp *fuse.ReadResponse, intr fus
                        log.Printf("error prioritizing %s: %s", fn.fsPath(), err)
                }
        }()
-       delayed := false
-       for {
-               dataWaiter := fn.FS.Client.DataWaiter()
-               n, err := fn.FS.Client.TorrentReadAt(infoHash, torrentOff, resp.Data)
-               switch err {
-               case nil:
-                       resp.Data = resp.Data[:n]
-                       return nil
-               case torrent.ErrDataNotReady:
-                       if !delayed {
-                               torrentfsDelayedReadRequests.Add(1)
-                               delayed = true
-                       }
-                       select {
-                       case <-dataWaiter:
-                       case <-fn.FS.destroyed:
-                               return fuse.EIO
-                       case <-intr:
-                               return fuse.EINTR
-                       }
-               default:
-                       log.Print(err)
-                       return err // bazil.org/fuse will convert generic errors appropriately.
-               }
+       n, err := readFull(fn.FS, infoHash, torrentOff, resp.Data, intr)
+       if err != nil {
+               return err
+       }
+       if n != size {
+               panic(fmt.Sprintf("%d < %d", n, size))
        }
+       return nil
 }
 
 type dirNode struct {