lib: move common code for creating flock.lock file into fs.CreateFlockFile

lib/fs/fs.go

@@ -13,6 +13,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/filestream"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/metrics"
+	"golang.org/x/sys/unix"
 )
 
 // ReadAtCloser is rand-access read interface.
@@ -385,3 +386,17 @@ func MustWriteData(w io.Writer, data []byte) {
 		logger.Panicf("BUG: writer wrote %d bytes instead of %d bytes", n, len(data))
 	}
 }
+
+// CreateFlockFile creates flock.lock file in the directory dir
+// and returns the handler to the file.
+func CreateFlockFile(dir string) (*os.File, error) {
+	flockFile := dir + "/flock.lock"
+	flockF, err := os.Create(flockFile)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create lock file %q: %s", flockFile, err)
+	}
+	if err := unix.Flock(int(flockF.Fd()), unix.LOCK_EX|unix.LOCK_NB); err != nil {
+		return nil, fmt.Errorf("cannot acquire lock on file %q: %s", flockFile, err)
+	}
+	return flockF, nil
+}

lib/mergeset/table.go

@@ -134,13 +134,9 @@ func OpenTable(path string) (*Table, error) {
 	}
 
 	// Protect from concurrent opens.
-	flockFile := path + "/flock.lock"
+	flockF, err := fs.CreateFlockFile(path)
-	flockF, err := os.Create(flockFile)
 	if err != nil {
-		return nil, fmt.Errorf("cannot create lock file %q: %s", flockFile, err)
+		return nil, err
-	}
-	if err := unix.Flock(int(flockF.Fd()), unix.LOCK_EX|unix.LOCK_NB); err != nil {
-		return nil, fmt.Errorf("cannot acquire lock on file %q: %s", flockFile, err)
 	}
 
 	// Open table parts.

lib/storage/storage.go

@@ -21,7 +21,6 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/memory"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
 	"github.com/VictoriaMetrics/fastcache"
-	"golang.org/x/sys/unix"
 )
 
 const maxRetentionMonths = 12 * 100
@@ -103,13 +102,10 @@ func OpenStorage(path string, retentionMonths int) (*Storage, error) {
 		return nil, fmt.Errorf("cannot create %q: %s", snapshotsPath, err)
 	}
 
-	flockFile := path + "/flock.lock"
+	// Protect from concurrent opens.
-	flockF, err := os.Create(flockFile)
+	flockF, err := fs.CreateFlockFile(path)
 	if err != nil {
-		return nil, fmt.Errorf("cannot create lock file %q: %s", flockFile, err)
+		return nil, err
-	}
-	if err := unix.Flock(int(flockF.Fd()), unix.LOCK_EX|unix.LOCK_NB); err != nil {
-		return nil, fmt.Errorf("cannot acquire lock on file %q: %s", flockFile, err)
 	}
 	s.flockF = flockF
 

lib/storage/table.go

@@ -10,7 +10,6 @@ import (
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
-	"golang.org/x/sys/unix"
 )
 
 // table represents a single table with time series data.
@@ -84,13 +83,10 @@ func openTable(path string, retentionMonths int, getDeletedMetricIDs func() map[
 		return nil, fmt.Errorf("cannot create directory for table %q: %s", path, err)
 	}
 
-	flockFile := path + "/flock.lock"
+	// Protect from concurrent opens.
-	flockF, err := os.Create(flockFile)
+	flockF, err := fs.CreateFlockFile(path)
 	if err != nil {
-		return nil, fmt.Errorf("cannot create lock file %q: %s", flockFile, err)
+		return nil, err
-	}
-	if err := unix.Flock(int(flockF.Fd()), unix.LOCK_EX|unix.LOCK_NB); err != nil {
-		return nil, fmt.Errorf("cannot acquire lock on file %q: %s", flockFile, err)
 	}
 
 	// Create directories for small and big partitions if they don't exist yet.