diff --git a/models/admin.go b/models/admin.go
index 94dc9b7a8c50..e573c9ba79c8 100644
--- a/models/admin.go
+++ b/models/admin.go
@@ -55,27 +55,30 @@ func (n *Notice) TrStr() string {
 
 // CreateNotice creates new system notice.
 func CreateNotice(tp NoticeType, desc string) error {
-	// prevent panic if database connection is not available at this point
-	if x == nil {
-		return fmt.Errorf("Could not save notice due database connection not being available: %d %s", tp, desc)
-	}
+	return createNotice(x, tp, desc)
+}
 
+func createNotice(e Engine, tp NoticeType, desc string) error {
 	n := &Notice{
 		Type:        tp,
 		Description: desc,
 	}
-	_, err := x.Insert(n)
+	_, err := e.Insert(n)
 	return err
 }
 
 // CreateRepositoryNotice creates new system notice with type NoticeRepository.
 func CreateRepositoryNotice(desc string) error {
-	return CreateNotice(NoticeRepository, desc)
+	return createNotice(x, NoticeRepository, desc)
 }
 
 // RemoveAllWithNotice removes all directories in given path and
 // creates a system notice when error occurs.
 func RemoveAllWithNotice(title, path string) {
+	removeAllWithNotice(x, title, path)
+}
+
+func removeAllWithNotice(e Engine, title, path string) {
 	var err error
 	// workaround for Go not being able to remove read-only files/folders: https://github.com/golang/go/issues/9606
 	// this bug should be fixed on Go 1.7, so the workaround should be removed when Gogs don't support Go 1.6 anymore:
@@ -91,7 +94,7 @@ func RemoveAllWithNotice(title, path string) {
 	if err != nil {
 		desc := fmt.Sprintf("%s [%s]: %v", title, path, err)
 		log.Warn(desc)
-		if err = CreateRepositoryNotice(desc); err != nil {
+		if err = createNotice(e, NoticeRepository, desc); err != nil {
 			log.Error(4, "CreateRepositoryNotice: %v", err)
 		}
 	}
diff --git a/models/repo.go b/models/repo.go
index e276a87ae6cc..3a1f149199cd 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -412,13 +412,18 @@ func (repo *Repository) ComposeMetas() map[string]string {
 }
 
 // DeleteWiki removes the actual and local copy of repository wiki.
-func (repo *Repository) DeleteWiki() {
+func (repo *Repository) DeleteWiki() error {
+	return repo.deleteWiki(x)
+}
+
+func (repo *Repository) deleteWiki(e Engine) error {
 	wikiPaths := []string{repo.WikiPath(), repo.LocalWikiPath()}
 	for _, wikiPath := range wikiPaths {
-		RemoveAllWithNotice("Delete repository wiki", wikiPath)
+		removeAllWithNotice(e, "Delete repository wiki", wikiPath)
 	}
 
-	x.Where("repo_id = ?", repo.ID).And("type = ?", UnitTypeWiki).Delete(new(RepoUnit))
+	_, err := e.Where("repo_id = ?", repo.ID).And("type = ?", UnitTypeWiki).Delete(new(RepoUnit))
+	return err
 }
 
 func (repo *Repository) getAssignees(e Engine) (_ []*User, err error) {
@@ -1620,27 +1625,25 @@ func DeleteRepository(uid, repoID int64) error {
 		return err
 	}
 
-	// Remove repository files.
+	// FIXME: Remove repository files should be executed after transaction succeed.
 	repoPath := repo.repoPath(sess)
-	RemoveAllWithNotice("Delete repository files", repoPath)
+	removeAllWithNotice(sess, "Delete repository files", repoPath)
 
-	repo.DeleteWiki()
+	repo.deleteWiki(sess)
 
 	// Remove attachment files.
 	for i := range attachmentPaths {
-		RemoveAllWithNotice("Delete attachment", attachmentPaths[i])
+		removeAllWithNotice(sess, "Delete attachment", attachmentPaths[i])
 	}
 
 	// Remove LFS objects
 	var lfsObjects []*LFSMetaObject
-
 	if err = sess.Where("repository_id=?", repoID).Find(&lfsObjects); err != nil {
 		return err
 	}
 
 	for _, v := range lfsObjects {
 		count, err := sess.Count(&LFSMetaObject{Oid: v.Oid})
-
 		if err != nil {
 			return err
 		}