What are equivalents of Linux ioctl functions FICLONE and FICLONERANGE ?

[Yuri]

On Linux files can be copied with:
ioctl(destFd, FICLONE, srcFd)


What would be the equivalent of this on FreeBSD?




Thanks,
Yuri

[Stefan Esser]

Post by Yuri
ioctl(destFd, FICLONE, srcFd)
What would be the equivalent of this on FreeBSD?

That would be copy_file_range(), but as on Linux, it does only
offer any benefit on filesystems that support copy-on-write or
potentially on network attached storage.

NFSv4 has recently gained support for server-side copies if
copy_file_range is used, for example. But UFS will fall back
to a normal copy operation.

ZFS should do this via block cloning, but that has not been
enabled by default, since it has a history of corrupted files
(and it is not clear, whether all border cases are covered in
the latest version).

Regards, STefan


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[Dag-Erling Smørgrav]

Post by Stefan Esser

Post by Yuri
ioctl(destFd, FICLONE, srcFd)
What would be the equivalent of this on FreeBSD?

That would be copy_file_range(), but as on Linux, it does only
offer any benefit on filesystems that support copy-on-write or
potentially on network attached storage.

Even without filesystem support, it still avoids copying the contents of
the file out to user space, so it's faster than a regular copy.

DES

[David Chisnall]

Post by Dag-Erling Smørgrav

Post by Stefan Esser

Post by Yuri
ioctl(destFd, FICLONE, srcFd)
What would be the equivalent of this on FreeBSD?

That would be copy_file_range(), but as on Linux, it does only
offer any benefit on filesystems that support copy-on-write or
potentially on network attached storage.

Even without filesystem support, it still avoids copying the contents of
the file out to user space, so it's faster than a regular copy.

Note that there is no in-kernel fallback path for if the file descriptor type does not support it. This means that you cannot use it, for example, for copies from an anonymous shared memory object to a regular file.

David

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