chore(btrfs): rename fs to btrfs

This is because the actions is specific for btrfs.

etcd/etcd.go

@@ -33,7 +33,7 @@ import (
 	ehttp "github.com/coreos/etcd/http"
 	"github.com/coreos/etcd/log"
 	"github.com/coreos/etcd/metrics"
-	"github.com/coreos/etcd/pkg/fs"
+	"github.com/coreos/etcd/pkg/btrfs"
 	"github.com/coreos/etcd/server"
 	"github.com/coreos/etcd/store"
 )
@@ -104,8 +104,8 @@ func (e *Etcd) Run() {
 	}
 
 	// Set NOCOW for data directory in btrfs
-	if fs.IsBtrfs(e.Config.DataDir) {
-		fs.SetNOCOWDir(e.Config.DataDir)
+	if btrfs.IsBtrfs(e.Config.DataDir) {
+		btrfs.SetNOCOWDir(e.Config.DataDir)
 	}
 
 	var mbName string

pkg/btrfs/fs.go

@@ -1,4 +1,4 @@
-package fs
+package btrfs
 
 import (
 	"os"

pkg/btrfs/fs_test.go

@@ -1,4 +1,4 @@
-package fs
+package btrfs
 
 import (
 	"io/ioutil"

test.sh

@@ -23,8 +23,8 @@ go test -v ./server/v2/tests
 go test -i ./mod/lock/v2/tests
 go test -v ./mod/lock/v2/tests
 
-go test -i ./pkg/fs
-go test -v ./pkg/fs
+go test -i ./pkg/btrfs
+go test -v ./pkg/btrfs
 
 go test -i ./tests/functional
 ETCD_BIN_PATH=$(pwd)/bin/etcd go test -v ./tests/functional