Various small fix-ups

.golangci.yml

@@ -6,8 +6,8 @@ linters:
     - unconvert
     - gofmt
     - goimports
-    - golint
     - ineffassign
+    - revive
     - vet
     - unused
     - misspell

README.md

@@ -1,19 +1,20 @@
 # continuity
 
-[![GoDoc](https://godoc.org/github.com/containerd/continuity?status.svg)](https://godoc.org/github.com/containerd/continuity)
-[![Build Status](https://travis-ci.org/containerd/continuity.svg?branch=main)](https://travis-ci.org/containerd/continuity)
+[![Go Reference](https://pkg.go.dev/badge/github.com/containerd/continuity.svg)](https://pkg.go.dev/github.com/containerd/continuity)
+[![Build Status](https://github.com/containerd/continuity/workflows/Continuity/badge.svg)](https://github.com/containerd/continuity/actions?query=workflow%3AContinuity+branch%3Amain)
 
 A transport-agnostic, filesystem metadata manifest system
 
 This project is a staging area for experiments in providing transport agnostic
 metadata storage.
 
-Please see https://github.com/opencontainers/specs/issues/11 for more details.
+See [opencontainers/runtime-spec#11](https://github.com/opencontainers/runtime-spec/issues/11)
+for more details.
 
 ## Manifest Format
 
 A continuity manifest encodes filesystem metadata in Protocol Buffers.
-Please refer to [proto/manifest.proto](proto/manifest.proto).
+Refer to [proto/manifest.proto](proto/manifest.proto) for more details.
 
 ## Usage
 
@@ -65,7 +66,7 @@ $ ./bin/continuity verify . /tmp/a.pb
 
 ## Platforms
 
-continuity primarily targets Linux.  continuity may compile for and work on
+continuity primarily targets Linux. Continuity may compile for and work on
 other operating systems, but those platforms are not tested.
 
 ## Contribution Guide

fs/copy.go

@@ -33,7 +33,7 @@ var bufferPool = &sync.Pool{
 	},
 }
 
-// XAttrErrorHandlers transform a non-nil xattr error.
+// XAttrErrorHandler transform a non-nil xattr error.
 // Return nil to ignore an error.
 // xattrKey can be empty for listxattr operation.
 type XAttrErrorHandler func(dst, src, xattrKey string, err error) error

fs/diff.go

@@ -22,9 +22,8 @@ import (
 	"path/filepath"
 	"strings"
 
-	"golang.org/x/sync/errgroup"
-
 	"github.com/sirupsen/logrus"
+	"golang.org/x/sync/errgroup"
 )
 
 // ChangeKind is the type of modification that