Cygwin copy_file_range() support with sparse file+FSCTL_DUPLICATE_EXTENTS_TO_FILE?

Václav Haisman vhaisman@gmail.com
Sun Jan 5 12:06:04 GMT 2025


On 05. 01. 25 7:31, Cedric Blancher via Cygwin wrote:
> Good morning!
> 
> Could Cygwin implement copy_file_range() support, including sparse
> file support so holes are preserved, and
> FSCTL_DUPLICATE_EXTENTS_TO_FILE support?

In theory, this could be used to implement that function. In practice, 
the block cloning is only supported by ReFS. See 
<https://learn.microsoft.com/en-us/windows/win32/api/winioctl/ni-winioctl-fsctl_duplicate_extents_to_file>

-- 
VH


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