graceful-fs functions as a drop-in replacement for the fs module, making various improvements.

The improvements are meant to normalize behavior across different platforms and environments, and to make filesystem access more resilient to errors.

graceful-fs:

• Queues up open and readdir calls, and retries them once something closes if there is an EMFILE error from too many file descriptors.
• fixes lchmod for Node versions prior to 0.6.2.
• implements fs.lutimes if possible. Otherwise it becomes a noop.
• ignores EINVAL and EPERM errors in chown, fchown or lchown if the user isn't root.
• makes lchmod and lchown become noops, if not available.
• retries reading a file if read results in EAGAIN error.

On Windows, it retries renaming a file for up to one second if EACCESS or EPERM error occurs, likely because antivirus software has locked the directory.