package fusefrontend import ( "sync" "syscall" ) import "github.com/rfjakob/gocryptfs/internal/toggledlog" var preallocWarn sync.Once // prealloc - preallocate space without changing the file size. This prevents // us from running out of space in the middle of an operation. func prealloc(fd int, off int64, len int64) (err error) { for { err = syscall.Fallocate(fd, FALLOC_FL_KEEP_SIZE, off, len) if err == syscall.EINTR { // fallocate, like many syscalls, can return EINTR. This is not an // error and just signifies that the operation was interrupted by a // signal and we should try again. continue } if err == syscall.EOPNOTSUPP { // ZFS does not support fallocate which caused gocryptfs to abort // every write operation: https://github.com/rfjakob/gocryptfs/issues/22 preallocWarn.Do(func() { toggledlog.Warn.Printf("Warning: The underlying filesystem " + "does not support fallocate(2). gocryptfs will continue working " + "but is no longer resistant against out-of-space errors.\n") }) return nil } return err } }