On 26/06/16 18:07, Alexandru Moise wrote: > On some filesystems (BTRFS), copying a file within the filesystem may > cross subvolume boundaries and we can use a lightweight reflink copy, > which is faster than a full file copy.
Note the above is accurate for mv, but for cp it's significant for _any_ copy within a BTRFS file system. > This is enabled by default because it's only an optimization for > the fall back copy and does not break user expectations or usability. That simplifies the argument a bit, but I think there is some weight behind this change. Coincidentally? I commented recently at https://news.ycombinator.com/item?id=11937781 where I describe there why cp may want to change this default behavior. However I allude there to an implementation using copy_file_range() to be more file system agnostic rather than trying something BTRFS specific and falling back each time. thanks, Pádraig
