Needless to say, your roof has a leak. If you have access to the attic you might be able to see water stains. Only problem with that is the water can run down some distance between the roof tiles and the roof deck (sheething) before it finds its way through the sheething and into the attic. But if you see water stains at least you'll have an idea where it's coming from.
Since it's a tile roof, it's not likely the roof itself just suddenly started leaking, unless somebody was up there and cracked a tile, or a tree branch fell on it. If there were any roof related events recently then that's most likely the cause. Otherwise, chances are it's coming from flashing somewhere that has come loose. Try to see if the leak is coming from anywhere near the chimney or a vent, or anything that either penetrates the roof or where the roof transitions into a wall or between separate sections of the roof.
How to fix it depends on the cause.
~ ToolGuy ~
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