What version of Go are you using (go version)?

$ go version
go version go1.12.7 dragonfly/amd64

Does this issue reproduce with the latest release?

1.12 is the latest

What operating system and processor architecture are you using (go env)?

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/hsw/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="dragonfly"
GOOS="dragonfly"
GOPATH="/home/hsw/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/dragonfly_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build675907830=/tmp/go-build -gno-record-gcc-switches"

What did you do?

In shell  on a DragonFly BSD Hammer2 partition create a non-empty directory:
  mkdir -p data/sub
  touch data/sub/file

Sample program to remove the directory::

package main

import(
        "fmt"
        "os"
)

func main() {
        err := os.RemoveAll("data")
        if nil != err {
                fmt.Printf("ra error: %s\n", err)
        }
}

What did you expect to see?

no output (as happens with UFS, MSDOS and Hammer1 fielsystems)

What did you see instead?

removal fails on Hammer2 with the following message:
ra error: directory not empty

suggested fix

Add the ENOTEMPTY to the condition in os/removeall_at.go

--- removeall_at.go.orig        2019-07-09 05:29:25.000000000 +0800
+++ removeall_at.go     2019-08-01 15:02:09.743625000 +0800
@@ -70,7 +70,7 @@
        // the parent directory, but this entry might still be a directory
        // whose contents need to be removed.
        // Otherwise just return the error.
-       if err != syscall.EISDIR && err != syscall.EPERM && err != syscall.EACCES {
+       if err != syscall.EISDIR && err != syscall.EPERM && err != syscall.EACCES && err != syscall.ENOTEMPTY {
                return &PathError{"unlinkat", base, err}
        }