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repository: separate Lock in-repository from lock handle

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Reduce Lock to a pure data transfer object and move the logic to
lockHandle.
This commit is contained in:
Michael Eischer
2026-06-07 13:34:36 +02:00
parent 81b6414c55
commit c87da70af9
5 changed files with 67 additions and 62 deletions
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internal/repository/lock.go
+4 -4
View File
@@ -14,7 +14,7 @@ import (
)
type lockContext struct {
lock *Lock
lock *lockHandle
cancel context.CancelFunc
refreshWG sync.WaitGroup
}
@@ -44,7 +44,7 @@ func LockRepo(ctx context.Context, repo *Repository, exclusive bool, retryLock t
// Lock wraps the ctx such that it is cancelled when the repository is unlocked
// cancelling the original context also stops the lock refresh
func (l *locker) Lock(ctx context.Context, r *Repository, exclusive bool, retryLock time.Duration, printRetry func(msg string), logger func(format string, args ...interface{})) (*unlocker, context.Context, error) {
var lock *Lock
var lock *lockHandle
var err error
retrySleep := minDuration(l.retrySleepStart, retryLock)
@@ -242,7 +242,7 @@ func (l *locker) monitorLockRefresh(ctx context.Context, lockInfo *lockContext,
}
}
func tryRefreshStaleLock(ctx context.Context, be backend.Backend, lock *Lock, cancel context.CancelFunc, logger func(format string, args ...interface{})) bool {
func tryRefreshStaleLock(ctx context.Context, be backend.Backend, lock *lockHandle, cancel context.CancelFunc, logger func(format string, args ...interface{})) bool {
freeze := backend.AsBackend[backend.FreezeBackend](be)
if freeze != nil {
debug.Log("freezing backend")
@@ -277,7 +277,7 @@ func (l *unlocker) Unlock() {
// RemoveStaleLocks deletes all locks detected as stale from the repository.
func RemoveStaleLocks(ctx context.Context, repo *Repository) (uint, error) {
var processed uint
err := forAllLocks(ctx, repo, nil, func(id restic.ID, lock *Lock, err error) error {
err := forAllLocks(ctx, repo, nil, func(id restic.ID, lock *lockHandle, err error) error {
if err != nil {
// ignore locks that cannot be loaded
debug.Log("ignore lock %v: %v", id, err)
internal/repository/lock_file.go
+52 -49
View File
@@ -20,16 +20,13 @@ import (
// if the passed in context was canceled.
const unlockCancelDelay = 1 * time.Minute
// Lock represents a process locking the repository for an operation.
//
// Lock is the in-repository representation of a repository lock file.
// There are two types of locks: exclusive and non-exclusive. There may be many
// different non-exclusive locks, but at most one exclusive lock, which can
// only be acquired while no non-exclusive lock is held.
//
// A lock must be refreshed regularly to not be considered stale, this must be
// triggered by regularly calling Refresh.
// A lock must be refreshed regularly to not be considered stale.
type Lock struct {
lock sync.Mutex
Time time.Time `json:"time"`
Exclusive bool `json:"exclusive"`
Hostname string `json:"hostname"`
@@ -37,15 +34,19 @@ type Lock struct {
PID int `json:"pid"`
UID uint32 `json:"uid,omitempty"`
GID uint32 `json:"gid,omitempty"`
}
// lockHandle is a reference to a lock file in the repository.
type lockHandle struct {
mu sync.Mutex
Lock
repo restic.Unpacked[restic.FileType]
lockID *restic.ID
}
// alreadyLockedError is returned when NewLock or NewExclusiveLock are unable to
// acquire the desired lock.
// alreadyLockedError is returned when newLock is unable to acquire the desired lock.
type alreadyLockedError struct {
otherLock *Lock
otherLock *lockHandle
}
func (e *alreadyLockedError) Error() string {
@@ -101,12 +102,14 @@ func TestSetLockTimeout(t testing.TB, d time.Duration) {
// exclusive lock is already held by another process, it returns an error
// that satisfies IsAlreadyLocked. If the new lock is exclusive, then other
// non-exclusive locks also result in an IsAlreadyLocked error.
func newLock(ctx context.Context, repo restic.Unpacked[restic.FileType], exclusive bool) (*Lock, error) {
lock := &Lock{
Time: time.Now(),
PID: os.Getpid(),
Exclusive: exclusive,
repo: repo,
func newLock(ctx context.Context, repo restic.Unpacked[restic.FileType], exclusive bool) (*lockHandle, error) {
lock := &lockHandle{
Lock: Lock{
Time: time.Now(),
PID: os.Getpid(),
Exclusive: exclusive,
},
repo: repo,
}
hn, err := os.Hostname()
@@ -139,7 +142,7 @@ func newLock(ctx context.Context, repo restic.Unpacked[restic.FileType], exclusi
return lock, nil
}
func (l *Lock) fillUserInfo() error {
func (l *lockHandle) fillUserInfo() error {
usr, err := user.Current()
if err != nil {
return nil
@@ -156,7 +159,7 @@ func (l *Lock) fillUserInfo() error {
// if there are any other locks, regardless if exclusive or not. If a
// non-exclusive lock is to be created, an error is only returned when an
// exclusive lock is found.
func (l *Lock) checkForOtherLocks(ctx context.Context) error {
func (l *lockHandle) checkForOtherLocks(ctx context.Context) error {
var err error
checkedIDs := restic.NewIDSet()
if l.lockID != nil {
@@ -176,7 +179,7 @@ func (l *Lock) checkForOtherLocks(ctx context.Context) error {
// Store updates in new IDSet to prevent data races
var m sync.Mutex
newCheckedIDs := checkedIDs.Clone()
err = forAllLocks(ctx, l.repo, checkedIDs, func(id restic.ID, lock *Lock, err error) error {
err = forAllLocks(ctx, l.repo, checkedIDs, func(id restic.ID, lock *lockHandle, err error) error {
if err != nil {
// if we cannot load a lock then it is unclear whether it can be ignored
// it could either be invalid or just unreadable due to network/permission problems
@@ -227,8 +230,8 @@ func cancelableDelay(ctx context.Context, delay time.Duration) error {
}
// createLock acquires the lock by creating a file in the repository.
func (l *Lock) createLock(ctx context.Context) (restic.ID, error) {
id, err := restic.SaveJSONUnpacked(ctx, l.repo, restic.LockFile, l)
func (l *lockHandle) createLock(ctx context.Context) (restic.ID, error) {
id, err := restic.SaveJSONUnpacked(ctx, l.repo, restic.LockFile, &l.Lock)
if err != nil {
return restic.ID{}, err
}
@@ -237,7 +240,7 @@ func (l *Lock) createLock(ctx context.Context) (restic.ID, error) {
}
// unlock removes the lock from the repository.
func (l *Lock) unlock(ctx context.Context) error {
func (l *lockHandle) unlock(ctx context.Context) error {
if l == nil || l.lockID == nil {
return nil
}
@@ -253,9 +256,9 @@ var staleLockTimeout = 30 * time.Minute
// stale returns true if the lock is stale. A lock is stale if the timestamp is
// older than 30 minutes or if it was created on the current machine and the
// process isn't alive any more.
func (l *Lock) stale() bool {
l.lock.Lock()
defer l.lock.Unlock()
func (l *lockHandle) stale() bool {
l.mu.Lock()
defer l.mu.Unlock()
debug.Log("testing if lock %v for process %d is stale", l.lockID, l.PID)
if time.Since(l.Time) > staleLockTimeout {
debug.Log("lock is stale, timestamp is too old: %v\n", l.Time)
@@ -305,18 +308,18 @@ func delayedCancelContext(parentCtx context.Context, delay time.Duration) (conte
// refresh refreshes the lock by creating a new file in the backend with a new
// timestamp. Afterwards the old lock is removed.
func (l *Lock) refresh(ctx context.Context) error {
func (l *lockHandle) refresh(ctx context.Context) error {
debug.Log("refreshing lock %v", l.lockID)
l.lock.Lock()
l.mu.Lock()
l.Time = time.Now()
l.lock.Unlock()
l.mu.Unlock()
id, err := l.createLock(ctx)
if err != nil {
return err
}
l.lock.Lock()
defer l.lock.Unlock()
l.mu.Lock()
defer l.mu.Unlock()
debug.Log("new lock ID %v", id)
oldLockID := l.lockID
@@ -329,7 +332,7 @@ func (l *Lock) refresh(ctx context.Context) error {
}
// refreshStaleLock is an extended variant of refresh that can also refresh stale lock files.
func (l *Lock) refreshStaleLock(ctx context.Context) error {
func (l *lockHandle) refreshStaleLock(ctx context.Context) error {
debug.Log("refreshing stale lock %v", l.lockID)
// refreshing a stale lock is possible if it still exists and continues to do
// so until after creating a new lock. The initial check avoids creating a new
@@ -341,9 +344,9 @@ func (l *Lock) refreshStaleLock(ctx context.Context) error {
return errRemovedLock
}
l.lock.Lock()
l.mu.Lock()
l.Time = time.Now()
l.lock.Unlock()
l.mu.Unlock()
id, err := l.createLock(ctx)
if err != nil {
return err
@@ -368,8 +371,8 @@ func (l *Lock) refreshStaleLock(ctx context.Context) error {
return errRemovedLock
}
l.lock.Lock()
defer l.lock.Unlock()
l.mu.Lock()
defer l.mu.Unlock()
debug.Log("new lock ID %v", id)
oldLockID := l.lockID
@@ -378,9 +381,9 @@ func (l *Lock) refreshStaleLock(ctx context.Context) error {
return l.repo.RemoveUnpacked(ctx, restic.LockFile, *oldLockID)
}
func (l *Lock) checkExistence(ctx context.Context) (bool, error) {
l.lock.Lock()
defer l.lock.Unlock()
func (l *lockHandle) checkExistence(ctx context.Context) (bool, error) {
l.mu.Lock()
defer l.mu.Unlock()
exists := false
@@ -394,9 +397,9 @@ func (l *Lock) checkExistence(ctx context.Context) (bool, error) {
return exists, err
}
func (l *Lock) String() string {
l.lock.Lock()
defer l.lock.Unlock()
func (l *lockHandle) String() string {
l.mu.Lock()
defer l.mu.Unlock()
text := fmt.Sprintf("PID %d on %s by %s (UID %d, GID %d)\nlock was created at %s (%s ago)\nstorage ID %v",
l.PID, l.Hostname, l.Username, l.UID, l.GID,
@@ -422,21 +425,17 @@ func init() {
}
// LoadLock loads and unserializes a lock from a repository.
func LoadLock(ctx context.Context, repo restic.LoaderUnpacked, id restic.ID) (*Lock, error) {
lock := &Lock{}
if err := restic.LoadJSONUnpacked(ctx, repo, restic.LockFile, id, lock); err != nil {
return nil, err
}
lock.lockID = &id
return lock, nil
func LoadLock(ctx context.Context, repo restic.LoaderUnpacked, id restic.ID) (Lock, error) {
var lock Lock
err := restic.LoadJSONUnpacked(ctx, repo, restic.LockFile, id, &lock)
return lock, err
}
// forAllLocks reads all locks in parallel and calls the given callback.
// It is guaranteed that the function is not run concurrently. If the
// callback returns an error, this function is cancelled and also returns that error.
// If a lock ID is passed via excludeID, it will be ignored.
func forAllLocks(ctx context.Context, repo restic.ListerLoaderUnpacked, excludeIDs restic.IDSet, fn func(restic.ID, *Lock, error) error) error {
func forAllLocks(ctx context.Context, repo restic.ListerLoaderUnpacked, excludeIDs restic.IDSet, fn func(restic.ID, *lockHandle, error) error) error {
var m sync.Mutex
// For locks decoding is nearly for free, thus just assume were only limited by IO
@@ -451,9 +450,13 @@ func forAllLocks(ctx context.Context, repo restic.ListerLoaderUnpacked, excludeI
return nil
}
lock, err := LoadLock(ctx, repo, id)
var handle *lockHandle
if err == nil {
handle = &lockHandle{Lock: lock, lockID: &id}
}
m.Lock()
defer m.Unlock()
return fn(id, lock, err)
return fn(id, handle, err)
})
}
internal/repository/lock_file_test.go
+9 -7
View File
@@ -158,10 +158,12 @@ func TestLockStale(t *testing.T) {
otherHostname := "other-" + hostname
for i, test := range staleLockTests {
lock := Lock{
Time: test.timestamp,
PID: test.pid,
Hostname: hostname,
lock := lockHandle{
Lock: Lock{
Time: test.timestamp,
PID: test.pid,
Hostname: hostname,
},
}
rtest.Assert(t, lock.stale() == test.stale,
@@ -194,7 +196,7 @@ func checkSingleLock(t *testing.T, repo restic.Lister) restic.ID {
return *lockID
}
func testLockRefresh(t *testing.T, refresh func(lock *Lock) error) {
func testLockRefresh(t *testing.T, refresh func(lock *lockHandle) error) {
repo := TestRepository(t)
TestSetLockTimeout(t, 5*time.Millisecond)
@@ -219,13 +221,13 @@ func testLockRefresh(t *testing.T, refresh func(lock *Lock) error) {
}
func TestLockRefresh(t *testing.T) {
testLockRefresh(t, func(lock *Lock) error {
testLockRefresh(t, func(lock *lockHandle) error {
return lock.refresh(context.TODO())
})
}
func TestLockRefreshStale(t *testing.T) {
testLockRefresh(t, func(lock *Lock) error {
testLockRefresh(t, func(lock *lockHandle) error {
return lock.refreshStaleLock(context.TODO())
})
}
internal/repository/lock_file_unix.go
+1 -1
View File
@@ -12,7 +12,7 @@ import (
// checkProcess will check if the process retaining the lock
// exists and responds to SIGHUP signal.
// Returns true if the process exists and responds.
func (l *Lock) processExists() bool {
func (l *lockHandle) processExists() bool {
proc, err := os.FindProcess(l.PID)
if err != nil {
debug.Log("error searching for process %d: %v\n", l.PID, err)
internal/repository/lock_file_windows.go
+1 -1
View File
@@ -8,7 +8,7 @@ import (
// checkProcess will check if the process retaining the lock exists.
// Returns true if the process exists.
func (l *Lock) processExists() bool {
func (l *lockHandle) processExists() bool {
proc, err := os.FindProcess(l.PID)
if err != nil {
debug.Log("error searching for process %d: %v\n", l.PID, err)