Is 4 hours long enough for a long rest for Elves?

The Long Rest rules read:

A long rest is a period of extended downtime, at least 8 hours long, during which you sleep or perform light activity: reading, talking, eating, or standing watch for no more than 2 hours of the rest period. If the rest is interrupted by a strenuous activity—such as attacking, taking damage, or casting a spell—you must start the rest over to gain any benefit from it, unless the interruption takes less than an hour. You must have at least 1 hit point to take a long rest. At the end of the rest, you regain all your hit points and half of your maximum number of Hit Dice (round up). You cannot benefit from more than one long rest in a 24-hour period.

The elven Trance racial trait reads as:

Trance: Elves do not need to sleep. Instead, they meditate deeply for 4 hours a day. (The Common word for such meditation is “trance.”) While meditating, you can dream after a fashion; such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep.

I have heard two views regarding these rules:

  • An Elf can get the benefit of a Long Rest in only 4 hours.
  • The 4 hours only applies to not being exhausted, 8 hours is still required get the benefits of a Long Rest.

Which is it? Please provide supporting information, possibly from previous versions.