So the documentation is clear that you can't mount a swap file through BTRFS (unless you use a loop device). Why isn't a NOCOW file that has been fully pre-allocated -- as with fallocate(1) -- not suitable for swapping? I found one reference to an unimplemented feature necessary for swap, but wouldn't it be reasonable for that feature to exist for NOCOW files? (or does this relate to my previous questions about the COW operation that happens after a snapshot?) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html