So, somebody wrote a program that converts, in-place, an #NTFS volume into #btrfs.
It even keeps an image of the original NTFS volume as a file in the resulting btrfs volume. This can be used to undo the conversion or deleted to free up space and make the conversion permanent.
That is absolutely wild.
Btrfs is copy-on-write, so keeping an image of the original NTFS does *not* involve duplicating every file on it. The blocks of the NTFS image are shared with the files on the new btrfs.
Which, again, is wild. One file's contents can be *part of* another, much larger file's contents, without duplication (until one of them is written to).
ARGVMI~1.PIF
Haelwenn /элвэн/ 