From 1eacfa948968c483d3232e4ca8e0a32df39f81e9 Mon Sep 17 00:00:00 2001 From: Ben Johnson Date: Wed, 2 Apr 2014 14:05:24 -0600 Subject: Add advisory file locking. This commit adds advisory locking via flock() to the database file. This ensures that two separate processes cannot both open the same data file which would cause corruption. Fixes #110. --- db.go | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/db.go b/db.go index 5cdad81..e4a4f9c 100644 --- a/db.go +++ b/db.go @@ -79,6 +79,14 @@ func Open(path string, mode os.FileMode) (*DB, error) { return nil, err } + // Lock file so that other processes using Bolt cannot use the database + // at the same time. This would cause corruption since the two processes + // would write meta pages and free pages separately. + if err := syscall.Flock(int(db.file.Fd()), syscall.LOCK_EX); err != nil { + _ = db.close() + return nil, err + } + // Default values for test hooks db.ops.writeAt = db.file.WriteAt @@ -267,6 +275,10 @@ func (db *DB) close() error { // Close file handles. if db.file != nil { + // Unlock the file. + _ = syscall.Flock(int(db.file.Fd()), syscall.LOCK_UN) + + // Close the file descriptor. if err := db.file.Close(); err != nil { return fmt.Errorf("db file close: %s", err) } -- cgit v1.2.3