Re: [RFC] git worktree: use filesystem cloning where supported

> ReFS has serious defects in its implementation.  If the data has been
> written but not flushed to disk, the resulting copy will be corrupt.  I
> just saw this come in with Git LFS[0] and I described it to a colleague
> as "horribly broken".  I definitely don't recommend adding support for
> this to Git until only fixed versions of Windows are publicly available.
> [snip]

Windows CopyFile API opens the source file shared-read deny-write, so you
cannot write to the file whilst it is being copied or you cannot copy
the file because
someone already has a write handle open.

So this wouldn't happen on Windows.

On Linux and Mac it seems they don't do the same. Linux FICLONE is supposed
to be atomic so no problems if that is used, and for MacOS I can't see anything
that would enable this to work.

So it would be Windows and Linux only.