ioctl.h

#ifndef DUPE_IOCTL
#define DUPE_IOCTL

#include <linux/fs.h>

#ifndef FIDEDUPERANGE

/* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */
#define FILE_DEDUPE_RANGE_SAME		0
#define FILE_DEDUPE_RANGE_DIFFERS	1

/* from struct btrfs_ioctl_file_extent_same_info */
struct file_dedupe_range_info {
	__s64 dest_fd;		/* in - destination file */
	__u64 dest_offset;	/* in - start of extent in destination */
	__u64 bytes_deduped;	/* out - total # of bytes we were able
				 * to dedupe from this file. */
	/* status of this dedupe operation:
	 * < 0 for error
	 * == FILE_DEDUPE_RANGE_SAME if dedupe succeeds
	 * == FILE_DEDUPE_RANGE_DIFFERS if data differs
	 */
	__s32 status;		/* out - see above description */
	__u32 reserved;		/* must be zero */
};

/* from struct btrfs_ioctl_file_extent_same_args */
struct file_dedupe_range {
	__u64 src_offset;	/* in - start of extent in source */
	__u64 src_length;	/* in - length of extent */
	__u16 dest_count;	/* in - total elements in info array */
	__u16 reserved1;	/* must be zero */
	__u32 reserved2;	/* must be zero */
	struct file_dedupe_range_info info[0];
};

#define FIDEDUPERANGE	_IOWR(0x94, 54, struct file_dedupe_range)

#endif // FIDEDUPERANGE

#endif