openfiletable: add inummap
Generates unique inode numbers for files on different devices. https://github.com/rfjakob/gocryptfs/issues/435
This commit is contained in:
parent
31ff557f85
commit
e5d5ab3973
63
internal/openfiletable/inummap.go
Normal file
63
internal/openfiletable/inummap.go
Normal file
@ -0,0 +1,63 @@
|
||||
package openfiletable
|
||||
|
||||
import (
|
||||
"sync"
|
||||
"syscall"
|
||||
)
|
||||
|
||||
// UINT64_MAX = 18446744073709551615
|
||||
const inumTranslateBase = 10000000000000000000
|
||||
|
||||
// InumMap ... see NewInumMap() for description.
|
||||
type InumMap struct {
|
||||
sync.Mutex
|
||||
baseDev uint64
|
||||
translate map[QIno]uint64
|
||||
translateNext uint64
|
||||
}
|
||||
|
||||
// NewInumMap returns a new inumMap.
|
||||
//
|
||||
// inumMap translates (device uint64, inode uint64) pairs to unique uint64
|
||||
// inode numbers.
|
||||
// Inode numbers on the "baseDev" are passed through unchanged (as long as they
|
||||
// are not higher than inumTranslateBase).
|
||||
// Inode numbers on other devices are remapped to the number space above
|
||||
// 10000000000000000000. The mapping is stored in a simple Go map. Entries
|
||||
// can only be added and are never removed.
|
||||
func NewInumMap(baseDev uint64) *InumMap {
|
||||
return &InumMap{
|
||||
baseDev: baseDev,
|
||||
translate: make(map[QIno]uint64),
|
||||
translateNext: inumTranslateBase,
|
||||
}
|
||||
}
|
||||
|
||||
// Translate maps the passed-in (device, inode) pair to a unique inode number.
|
||||
func (m *InumMap) Translate(in QIno) (out uint64) {
|
||||
if in.Dev == m.baseDev && in.Ino < inumTranslateBase {
|
||||
return in.Ino
|
||||
}
|
||||
m.Lock()
|
||||
defer m.Unlock()
|
||||
out = m.translate[in]
|
||||
if out != 0 {
|
||||
return out
|
||||
}
|
||||
out = m.translateNext
|
||||
m.translate[in] = m.translateNext
|
||||
m.translateNext++
|
||||
return out
|
||||
}
|
||||
|
||||
// TranslateStat translates the inode number contained in "st" if neccessary.
|
||||
// Convience wrapper around Translate().
|
||||
func (m *InumMap) TranslateStat(st *syscall.Stat_t) {
|
||||
in := QInoFromStat(st)
|
||||
st.Ino = m.Translate(in)
|
||||
}
|
||||
|
||||
// Count returns the number of entries in the translation table.
|
||||
func (m *InumMap) Count() int {
|
||||
return len(m.translate)
|
||||
}
|
81
internal/openfiletable/inummap_test.go
Normal file
81
internal/openfiletable/inummap_test.go
Normal file
@ -0,0 +1,81 @@
|
||||
package openfiletable
|
||||
|
||||
import (
|
||||
"sync"
|
||||
"testing"
|
||||
)
|
||||
|
||||
func TestTranslate(t *testing.T) {
|
||||
const baseDev = 12345
|
||||
m := NewInumMap(baseDev)
|
||||
|
||||
q := QIno{Dev: baseDev, Ino: 1}
|
||||
out := m.Translate(q)
|
||||
if out != 1 {
|
||||
t.Errorf("expected 1, got %d", out)
|
||||
}
|
||||
q.Ino = inumTranslateBase
|
||||
out = m.Translate(q)
|
||||
if out < inumTranslateBase {
|
||||
t.Errorf("got %d", out)
|
||||
}
|
||||
out2 := m.Translate(q)
|
||||
if out2 != out {
|
||||
t.Errorf("unstable mapping: %d %d", out2, out)
|
||||
}
|
||||
}
|
||||
|
||||
func TestTranslateStress(t *testing.T) {
|
||||
const baseDev = 12345
|
||||
m := NewInumMap(baseDev)
|
||||
var wg sync.WaitGroup
|
||||
wg.Add(4)
|
||||
go func() {
|
||||
q := QIno{Dev: baseDev}
|
||||
for i := uint64(1); i <= 10000; i++ {
|
||||
q.Ino = i
|
||||
out := m.Translate(q)
|
||||
if out != i {
|
||||
t.Fail()
|
||||
}
|
||||
}
|
||||
wg.Done()
|
||||
}()
|
||||
go func() {
|
||||
q := QIno{Dev: baseDev}
|
||||
for i := uint64(1); i <= 10000; i++ {
|
||||
q.Ino = inumTranslateBase + i
|
||||
out := m.Translate(q)
|
||||
if out < inumTranslateBase {
|
||||
t.Fail()
|
||||
}
|
||||
}
|
||||
wg.Done()
|
||||
}()
|
||||
go func() {
|
||||
q := QIno{Dev: 9999999}
|
||||
for i := uint64(1); i <= 10000; i++ {
|
||||
q.Ino = i
|
||||
out := m.Translate(q)
|
||||
if out < inumTranslateBase {
|
||||
t.Fail()
|
||||
}
|
||||
}
|
||||
wg.Done()
|
||||
}()
|
||||
go func() {
|
||||
q := QIno{Dev: 4444444}
|
||||
for i := uint64(1); i <= 10000; i++ {
|
||||
q.Ino = i
|
||||
out := m.Translate(q)
|
||||
if out < inumTranslateBase {
|
||||
t.Fail()
|
||||
}
|
||||
}
|
||||
wg.Done()
|
||||
}()
|
||||
wg.Wait()
|
||||
if m.Count() != 30000 {
|
||||
t.Fail()
|
||||
}
|
||||
}
|
Loading…
Reference in New Issue
Block a user