From 409c9396213b3262cd916ee4b60a783150e8033b Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Thu, 28 Nov 2019 13:36:02 +0200
Subject: [PATCH] lib/backup: remove `flock.lock` file in empty dirs

This fixes an issue when VictoriaMetrics doesn't see the restored data after the following operations:

1. Stop VictoriaMetrics.
2. Delete `<-storageDataPath>` dir.
3. Start VictoriaMetrics, then stop it.
4. Restore data from backup with `vmrestore`.
5. Start VictoriaMetrics.

`vmrestore` didn't delete properly empty dirs in `<-storageDataPath>/indexdb` because of the remaining `flock.lock` files in these dirs.
---
 lib/backup/fscommon/fscommon.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/backup/fscommon/fscommon.go b/lib/backup/fscommon/fscommon.go
index 157c9a31e..d6680aa62 100644
--- a/lib/backup/fscommon/fscommon.go
+++ b/lib/backup/fscommon/fscommon.go
@@ -173,6 +173,7 @@ func removeEmptyDirsInternal(d *os.File) (bool, error) {
 		return false, fmt.Errorf("cannot read directory contents in %q: %s", dir, err)
 	}
 	dirEntries := 0
+	hasFlock := false
 	for _, fi := range fis {
 		name := fi.Name()
 		if name == "." || name == ".." {
@@ -191,6 +192,10 @@ func removeEmptyDirsInternal(d *os.File) (bool, error) {
 			continue
 		}
 		if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
+			if name == "flock.lock" {
+				hasFlock = true
+				continue
+			}
 			// Skip plain files.
 			dirEntries++
 			continue
@@ -244,6 +249,12 @@ func removeEmptyDirsInternal(d *os.File) (bool, error) {
 		return false, nil
 	}
 	logger.Infof("removing empty dir %q", dir)
+	if hasFlock {
+		flockFilepath := dir + "/flock.lock"
+		if err := os.Remove(flockFilepath); err != nil {
+			return false, fmt.Errorf("cannot remove %q: %s", flockFilepath, err)
+		}
+	}
 	if err := os.Remove(dir); err != nil {
 		return false, fmt.Errorf("cannot remove %q: %s", dir, err)
 	}