Partial write could corrupt BuntDB database

main.go

package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"

	"github.com/tidwall/buntdb"
)

const VolumeName = "/Volumes/SMALL" // Tiny Volume
const VolumeSize = 0x40000000       // 1 GB
const ValueSize = 0xA00000          // 10 MB

func main() {
	// Create a very small volume.
	// I created a 1GB volume at /Volumes/SMALL

	// Delete the previous "data.db", if exists
	if err := os.RemoveAll(filepath.Join(VolumeName, "data.db")); err != nil {
		panic(err)
	}

	// create an blank file that is half the size of the volume
	println("* write blank file")
	if err := ioutil.WriteFile(filepath.Join(VolumeName, "blank"),
		make([]byte, VolumeSize/2), 0600); err != nil {
		panic(err)
	}

	// Open the database
	println("* open database")
	db, err := buntdb.Open(filepath.Join(VolumeName, "data.db"))
	if err != nil {
		panic(err)
	}

	// disable background auto shrinking
	var cfg buntdb.Config
	if err := db.ReadConfig(&cfg); err != nil {
		panic(err)
	}
	cfg.AutoShrinkDisabled = true
	if err := db.SetConfig(cfg); err != nil {
		panic(err)
	}

	// create a very big value. One that could not possiblly be written in a
	// single syscall, but much smaller than the 'blank' file size
	value := strings.Repeat("*", ValueSize) // 10MB
	failCount := 0
	// start writing transactions to disk
	println("* write transactions")
	for i := 0; ; i++ {
		err := db.Update(func(tx *buntdb.Tx) error {
			key := fmt.Sprintf("key:%d", i)
			_, _, err := tx.Set(key, value, nil)
			return err
		})
		if err != nil {
			// A failure is probably because the file system ran out of
			// disk space. It's possible that this was a partial write leaving
			// the database in a potentially corrupted state.
			failCount++
			if failCount == 2 {
				println("* fail twice")
				println("* finished writing")
				break
			}
			println("* fail once")
			// Let's delete the 'blank' file and continue writing.
			println("* delete blank file")
			err := os.RemoveAll(filepath.Join(VolumeName, "blank"))
			if err != nil {
				panic(err)
			}
			println("* write more transactions")
		}
	}
	println("* close database")
	if err := db.Close(); err != nil {
		panic(err)
	}
	println("* reopen database")
	db, err = buntdb.Open(filepath.Join(VolumeName, "data.db"))
	if err != nil {
		panic(err)
	}

	// disable background auto shrinking
	if err := db.ReadConfig(&cfg); err != nil {
		panic(err)
	}
	cfg.AutoShrinkDisabled = true
	if err := db.SetConfig(cfg); err != nil {
		panic(err)
	}
	if err := db.Close(); err != nil {
		panic(err)
	}

}