diff --git a/repository/git.go b/repository/git.go
index e67e12f54735dba5fc8091a39fbe900a1f692c20..2348f5d57e9140d2df8b568e2304f154418c4dd3 100644
--- a/repository/git.go
+++ b/repository/git.go
@@ -367,6 +367,9 @@ func (repo *GitRepo) GetTreeHash(commit Hash) (Hash, error) {
 // GetOrCreateClock return a Lamport clock stored in the Repo.
 // If the clock doesn't exist, it's created.
 func (repo *GitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
+	repo.clocksMutex.Lock()
+	defer repo.clocksMutex.Unlock()
+
 	c, err := repo.getClock(name)
 	if err == nil {
 		return c, nil
@@ -375,9 +378,6 @@ func (repo *GitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
 		return nil, err
 	}
 
-	repo.clocksMutex.Lock()
-	defer repo.clocksMutex.Unlock()
-
 	c, err = lamport.NewPersistedClock(repo.LocalStorage(), name+"-clock")
 	if err != nil {
 		return nil, err
@@ -388,9 +388,6 @@ func (repo *GitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
 }
 
 func (repo *GitRepo) getClock(name string) (lamport.Clock, error) {
-	repo.clocksMutex.Lock()
-	defer repo.clocksMutex.Unlock()
-
 	if c, ok := repo.clocks[name]; ok {
 		return c, nil
 	}
diff --git a/repository/gogit.go b/repository/gogit.go
index 0d34c00aa5a11ca92a5374e7f88e27a3e8ffab9c..741982aaddc91a2a5ddecb927bc33a12c9eaf6f3 100644
--- a/repository/gogit.go
+++ b/repository/gogit.go
@@ -604,6 +604,9 @@ func (repo *GoGitRepo) ListCommits(ref string) ([]Hash, error) {
 // GetOrCreateClock return a Lamport clock stored in the Repo.
 // If the clock doesn't exist, it's created.
 func (repo *GoGitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
+	repo.clocksMutex.Lock()
+	defer repo.clocksMutex.Unlock()
+
 	c, err := repo.getClock(name)
 	if err == nil {
 		return c, nil
@@ -612,9 +615,6 @@ func (repo *GoGitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
 		return nil, err
 	}
 
-	repo.clocksMutex.Lock()
-	defer repo.clocksMutex.Unlock()
-
 	c, err = lamport.NewPersistedClock(repo.localStorage, name+"-clock")
 	if err != nil {
 		return nil, err
@@ -625,9 +625,6 @@ func (repo *GoGitRepo) GetOrCreateClock(name string) (lamport.Clock, error) {
 }
 
 func (repo *GoGitRepo) getClock(name string) (lamport.Clock, error) {
-	repo.clocksMutex.Lock()
-	defer repo.clocksMutex.Unlock()
-
 	if c, ok := repo.clocks[name]; ok {
 		return c, nil
 	}
diff --git a/repository/mock_repo.go b/repository/mock_repo.go
index 74d4cae7ae635c44c84958319adb54b49d8d6d33..02e5010f39a6a25973a7b25a511ba2b32fb516fe 100644
--- a/repository/mock_repo.go
+++ b/repository/mock_repo.go
@@ -4,6 +4,7 @@ import (
 	"crypto/sha1"
 	"fmt"
 	"strings"
+	"sync"
 
 	"github.com/99designs/keyring"
 	"github.com/go-git/go-billy/v5"
@@ -337,6 +338,7 @@ func (m mockRepoForTest) EraseFromDisk() error {
 }
 
 type mockRepoClock struct {
+	mu     sync.Mutex
 	clocks map[string]lamport.Clock
 }
 
@@ -347,6 +349,9 @@ func NewMockRepoClock() *mockRepoClock {
 }
 
 func (r *mockRepoClock) GetOrCreateClock(name string) (lamport.Clock, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
 	if c, ok := r.clocks[name]; ok {
 		return c, nil
 	}