From 220b61e988ecf0a1667943fde98513583b8c1338 Mon Sep 17 00:00:00 2001 From: Ben Johnson Date: Mon, 29 Feb 2016 22:58:44 -0700 Subject: [PATCH] move to separate lock file on windows --- bolt_unix.go | 8 ++++---- bolt_unix_solaris.go | 8 ++++---- bolt_windows.go | 22 ++++++++++++++++++---- db.go | 15 +++++++++++---- 4 files changed, 37 insertions(+), 16 deletions(-) diff --git a/bolt_unix.go b/bolt_unix.go index 4b0723a..cad62dd 100644 --- a/bolt_unix.go +++ b/bolt_unix.go @@ -11,7 +11,7 @@ import ( ) // flock acquires an advisory lock on a file descriptor. -func flock(f *os.File, exclusive bool, timeout time.Duration) error { +func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error { var t time.Time for { // If we're beyond our timeout then return an error. @@ -27,7 +27,7 @@ func flock(f *os.File, exclusive bool, timeout time.Duration) error { } // Otherwise attempt to obtain an exclusive lock. - err := syscall.Flock(int(f.Fd()), flag|syscall.LOCK_NB) + err := syscall.Flock(int(db.file.Fd()), flag|syscall.LOCK_NB) if err == nil { return nil } else if err != syscall.EWOULDBLOCK { @@ -40,8 +40,8 @@ func flock(f *os.File, exclusive bool, timeout time.Duration) error { } // funlock releases an advisory lock on a file descriptor. -func funlock(f *os.File) error { - return syscall.Flock(int(f.Fd()), syscall.LOCK_UN) +func funlock(db *DB) error { + return syscall.Flock(int(db.file.Fd()), syscall.LOCK_UN) } // mmap memory maps a DB's data file. diff --git a/bolt_unix_solaris.go b/bolt_unix_solaris.go index 1c4e48d..307bf2b 100644 --- a/bolt_unix_solaris.go +++ b/bolt_unix_solaris.go @@ -11,7 +11,7 @@ import ( ) // flock acquires an advisory lock on a file descriptor. -func flock(f *os.File, exclusive bool, timeout time.Duration) error { +func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error { var t time.Time for { // If we're beyond our timeout then return an error. @@ -32,7 +32,7 @@ func flock(f *os.File, exclusive bool, timeout time.Duration) error { } else { lock.Type = syscall.F_RDLCK } - err := syscall.FcntlFlock(f.Fd(), syscall.F_SETLK, &lock) + err := syscall.FcntlFlock(db.file.Fd(), syscall.F_SETLK, &lock) if err == nil { return nil } else if err != syscall.EAGAIN { @@ -45,13 +45,13 @@ func flock(f *os.File, exclusive bool, timeout time.Duration) error { } // funlock releases an advisory lock on a file descriptor. -func funlock(f *os.File) error { +func funlock(db *DB) error { var lock syscall.Flock_t lock.Start = 0 lock.Len = 0 lock.Type = syscall.F_UNLCK lock.Whence = 0 - return syscall.FcntlFlock(uintptr(f.Fd()), syscall.F_SETLK, &lock) + return syscall.FcntlFlock(uintptr(db.file.Fd()), syscall.F_SETLK, &lock) } // mmap memory maps a DB's data file. diff --git a/bolt_windows.go b/bolt_windows.go index 91c4968..d538e6a 100644 --- a/bolt_windows.go +++ b/bolt_windows.go @@ -16,6 +16,8 @@ var ( ) const ( + lockExt = ".lock" + // see https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx flagLockExclusive = 2 flagLockFailImmediately = 1 @@ -46,7 +48,16 @@ func fdatasync(db *DB) error { } // flock acquires an advisory lock on a file descriptor. -func flock(f *os.File, exclusive bool, timeout time.Duration) error { +func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error { + // Create a separate lock file on windows because a process + // cannot share an exclusive lock on the same file. This is + // needed during Tx.WriteTo(). + f, err := os.OpenFile(db.path+lockExt, os.O_CREATE, mode) + if err != nil { + return err + } + db.lockfile = f + var t time.Time for { // If we're beyond our timeout then return an error. @@ -62,7 +73,7 @@ func flock(f *os.File, exclusive bool, timeout time.Duration) error { flag |= flagLockExclusive } - err := lockFileEx(syscall.Handle(f.Fd()), flag, 0, 1, 0, &syscall.Overlapped{}) + err := lockFileEx(syscall.Handle(db.lockfile.Fd()), flag, 0, 1, 0, &syscall.Overlapped{}) if err == nil { return nil } else if err != errLockViolation { @@ -75,8 +86,11 @@ func flock(f *os.File, exclusive bool, timeout time.Duration) error { } // funlock releases an advisory lock on a file descriptor. -func funlock(f *os.File) error { - return unlockFileEx(syscall.Handle(f.Fd()), 0, 1, 0, &syscall.Overlapped{}) +func funlock(db *DB) error { + err := unlockFileEx(syscall.Handle(db.lockfile.Fd()), 0, 1, 0, &syscall.Overlapped{}) + db.lockfile.Close() + os.Remove(db.path+lockExt) + return err } // mmap memory maps a DB's data file. diff --git a/db.go b/db.go index 0f1e1bc..501d36a 100644 --- a/db.go +++ b/db.go @@ -93,6 +93,7 @@ type DB struct { path string file *os.File + lockfile *os.File // windows only dataref []byte // mmap'ed readonly, write throws SEGV data *[maxMapSize]byte datasz int @@ -177,7 +178,7 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) { // if !options.ReadOnly. // The database file is locked using the shared lock (more than one process may // hold a lock at the same time) otherwise (options.ReadOnly is set). - if err := flock(db.file, !db.readOnly, options.Timeout); err != nil { + if err := flock(db, mode, !db.readOnly, options.Timeout); err != nil { _ = db.close() return nil, err } @@ -379,6 +380,10 @@ func (db *DB) Close() error { } func (db *DB) close() error { + if !db.opened { + return nil + } + db.opened = false db.freelist = nil @@ -397,7 +402,7 @@ func (db *DB) close() error { // No need to unlock read-only file. if !db.readOnly { // Unlock the file. - if err := funlock(db.file); err != nil { + if err := funlock(db); err != nil { log.Printf("bolt.Close(): funlock error: %s", err) } } @@ -824,8 +829,10 @@ func (db *DB) grow(sz int) error { // Truncate and fsync to ensure file size metadata is flushed. // https://github.com/boltdb/bolt/issues/284 if !db.NoGrowSync && !db.readOnly { - if err := db.file.Truncate(int64(sz)); err != nil { - return fmt.Errorf("file resize error: %s", err) + if runtime.GOOS != "windows" { + if err := db.file.Truncate(int64(sz)); err != nil { + return fmt.Errorf("file resize error: %s", err) + } } if err := db.file.Sync(); err != nil { return fmt.Errorf("file sync error: %s", err)