Here's Locks and Bolts, which is the one I was looking for. The Ritchie family's tune is remarkably lovely.

Locks and Bolts
traditional, Ritchie Family version

I dreamed of my true love last night
All in my arms I held her
When I awoke it was a dream
I was forced to lie without her

Her yellow hair like links of gold
Came rollin' down the pillow
Her yellow hair like links of gold
Came rollin' down my pillow

I rode up to her uncle's hall
Inquiring for my darlin'
Her uncle said "There's no such here,"
Which set my heart to wonderin'

I turned my horse to ride away
She called down from a winder
And said, "My dear I'd be with you
But locks and bolts doth hinder."

My passion flew, my sword I drew
Into that room I ventured
My passion flew, my sword I drew
Into that room I entered

The blood was shed on every hand
I took her from among them
Come now, brave boys who'll have your love
You must fight till you overcome them,

Her yellow hair like links of gold
Comes rollin' down my pillow
Her yellow hair like links of gold
Comes rollin' down my pillow