Aha, thanks a lot Zygo for the hint about fiemap. I will try this, it could indeed save an awful lot of I/O.
Stef Bon -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
