cp --reflink and BTRFS_IOC_CLONE

[Steve French]

Do any other file systems other than btrfs support "cp --reflink" (ie
BTRFS_IOC_CLONE). I am cleaning the patches to cifs.ko to do this at
least for SMB2/SMB2.1/SMB3, but I thought that at the kernel file
system summit somebody mentioned other in kernel file systems that
support the copy offload ioctl that cp --reflink invokes (ie
BTRFS_IOC_CLONE).,

[David Disseldorp]

On Wed, 16 Oct 2013 15:02:11 -0500

Post by Steve French
Do any other file systems other than btrfs support "cp --reflink" (ie
BTRFS_IOC_CLONE). I am cleaning the patches to cifs.ko to do this at
least for SMB2/SMB2.1/SMB3, but I thought that at the kernel file
system summit somebody mentioned other in kernel file systems that
support the copy offload ioctl that cp --reflink invokes (ie
BTRFS_IOC_CLONE).,

I think OCFS2 does via OCFS2_IOC_REFLINK.

Cheers, David

[Steve French]

I see ocfs2 has a reflink-like call (see ocfs2/ioctl.h)

/* Used to pass 2 file names to reflink. */
struct reflink_arguments {
__u64 old_path;
__u64 new_path;
__u64 preserve;
};
#define OCFS2_IOC_REFLINK _IOW('o', 4, struct reflink_arguments)

Its format more closely matches SIS_COPYFILE (which I can experiment
with, but probably works even on cifs not just SMB2/SMB3).

Post by David Disseldorp
On Wed, 16 Oct 2013 15:02:11 -0500

Post by Steve French
Do any other file systems other than btrfs support "cp --reflink" (ie
BTRFS_IOC_CLONE). I am cleaning the patches to cifs.ko to do this at
least for SMB2/SMB2.1/SMB3, but I thought that at the kernel file
system summit somebody mentioned other in kernel file systems that
support the copy offload ioctl that cp --reflink invokes (ie
BTRFS_IOC_CLONE).,

I think OCFS2 does via OCFS2_IOC_REFLINK.
Cheers, David