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.
GitHub - maharmstone/ntfs2btrfsGitHub
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).
@argv_minus_one Well for me it's kind of normal but I've been a ZFS user since at least 2007, so Copy-on-Write abilities are something I'm familiar with.