fix(share/eds): don't use in-memory buffer for mount after shard reco…

…ver (#2554)

When shard recovered in dagstore, it was read from in-memory mount, that
could have been read 0 times and had no in-memory buffer.

share/eds/store.go

@@ -569,7 +569,7 @@ type inMemoryOnceMount struct {
 }
 
 func (m *inMemoryOnceMount) Fetch(ctx context.Context) (mount.Reader, error) {
- if !m.readOnce.Swap(true) {
+ if m.buf != nil && !m.readOnce.Swap(true) {
  reader := &inMemoryReader{Reader: bytes.NewReader(m.buf.Bytes())}
  // release memory for gc, otherwise buffer will stick forever
  m.buf = nil