diff --git a/bolt_unix.go b/bolt_unix.go index cad62dda1..17be1e4e8 100644 --- a/bolt_unix.go +++ b/bolt_unix.go @@ -13,29 +13,32 @@ import ( // flock acquires an advisory lock on a file descriptor. func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error { var t time.Time + if timeout != 0 { + t = time.Now() + } + fd := db.file.Fd() + flag := syscall.LOCK_NB + if exclusive { + flag |= syscall.LOCK_EX + } else { + flag |= syscall.LOCK_SH + } for { - // If we're beyond our timeout then return an error. - // This can only occur after we've attempted a flock once. - if t.IsZero() { - t = time.Now() - } else if timeout > 0 && time.Since(t) > timeout { - return ErrTimeout - } - flag := syscall.LOCK_SH - if exclusive { - flag = syscall.LOCK_EX - } - - // Otherwise attempt to obtain an exclusive lock. - err := syscall.Flock(int(db.file.Fd()), flag|syscall.LOCK_NB) + // Attempt to obtain an exclusive lock. + err := syscall.Flock(int(fd), flag) if err == nil { return nil } else if err != syscall.EWOULDBLOCK { return err } + // If we timed out then return an error. + if timeout != 0 && time.Since(t) > timeout - flockRetryTimeout { + return ErrTimeout + } + // Wait for a bit and try again. - time.Sleep(50 * time.Millisecond) + time.Sleep(flockRetryTimeout) } } diff --git a/bolt_unix_solaris.go b/bolt_unix_solaris.go index 307bf2b3e..c397f87d1 100644 --- a/bolt_unix_solaris.go +++ b/bolt_unix_solaris.go @@ -13,34 +13,33 @@ import ( // flock acquires an advisory lock on a file descriptor. func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error { var t time.Time + if timeout != 0 { + t = time.Now() + } + fd := db.file.Fd() + var lockType int16 + if exclusive { + lockType = syscall.F_WRLCK + } else { + lockType = syscall.F_RDLCK + } for { - // If we're beyond our timeout then return an error. - // This can only occur after we've attempted a flock once. - if t.IsZero() { - t = time.Now() - } else if timeout > 0 && time.Since(t) > timeout { - return ErrTimeout - } - var lock syscall.Flock_t - lock.Start = 0 - lock.Len = 0 - lock.Pid = 0 - lock.Whence = 0 - lock.Pid = 0 - if exclusive { - lock.Type = syscall.F_WRLCK - } else { - lock.Type = syscall.F_RDLCK - } - err := syscall.FcntlFlock(db.file.Fd(), syscall.F_SETLK, &lock) + // Attempt to obtain an exclusive lock. + lock := syscall.Flock_t{Type: lockType} + err := syscall.FcntlFlock(fd, syscall.F_SETLK, &lock) if err == nil { return nil } else if err != syscall.EAGAIN { return err } + // If we timed out then return an error. + if timeout != 0 && time.Since(t) > timeout - flockRetryTimeout { + return ErrTimeout + } + // Wait for a bit and try again. - time.Sleep(50 * time.Millisecond) + time.Sleep(flockRetryTimeout) } } diff --git a/bolt_windows.go b/bolt_windows.go index b00fb0720..cad774cb1 100644 --- a/bolt_windows.go +++ b/bolt_windows.go @@ -59,29 +59,30 @@ func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) erro db.lockfile = f var t time.Time + if timeout != 0 { + t = time.Now() + } + fd := db.file.Fd() + var flag uint32 = flagLockFailImmediately + if exclusive { + flag |= flagLockExclusive + } for { - // If we're beyond our timeout then return an error. - // This can only occur after we've attempted a flock once. - if t.IsZero() { - t = time.Now() - } else if timeout > 0 && time.Since(t) > timeout { - return ErrTimeout - } - - var flag uint32 = flagLockFailImmediately - if exclusive { - flag |= flagLockExclusive - } - - err := lockFileEx(syscall.Handle(db.lockfile.Fd()), flag, 0, 1, 0, &syscall.Overlapped{}) + // Attempt to obtain an exclusive lock. + err := lockFileEx(syscall.Handle(fd), flag, 0, 1, 0, &syscall.Overlapped{}) if err == nil { return nil } else if err != errLockViolation { return err } + // If we timed oumercit then return an error. + if timeout != 0 && time.Since(t) > timeout - flockRetryTimeout { + return ErrTimeout + } + // Wait for a bit and try again. - time.Sleep(50 * time.Millisecond) + time.Sleep(flockRetryTimeout) } } diff --git a/db.go b/db.go index 473036873..e4475039a 100644 --- a/db.go +++ b/db.go @@ -40,6 +40,9 @@ const ( // default page size for db is set to the OS page size. var defaultPageSize = os.Getpagesize() +// The time elapsed between consecutive file locking attempts. +const flockRetryTimeout = 50 * time.Millisecond + // DB represents a collection of buckets persisted to a file on disk. // All data access is performed through transactions which can be obtained through the DB. // All the functions on DB will return a ErrDatabaseNotOpen if accessed before Open() is called.