Function dmu_diff

freebsd/contrib/openzfs/module/zfs/dmu_diff.c:166–240

}

int
dmu_diff(const char *tosnap_name, const char *fromsnap_name,
    zfs_file_t *fp, offset_t *offp)
{
	dmu_diffarg_t da;
	dsl_dataset_t *fromsnap;
	dsl_dataset_t *tosnap;
	dsl_pool_t *dp;
	int error;
	uint64_t fromtxg;

	if (strchr(tosnap_name, '@') == NULL ||
	    strchr(fromsnap_name, '@') == NULL)
		return (SET_ERROR(EINVAL));

	error = dsl_pool_hold(tosnap_name, FTAG, &dp);
	if (error != 0)
		return (error);

	error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
	if (error != 0) {
		dsl_pool_rele(dp, FTAG);
		return (error);
	}

	error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
	if (error != 0) {
		dsl_dataset_rele(tosnap, FTAG);
		dsl_pool_rele(dp, FTAG);
		return (error);
	}

	if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
		dsl_dataset_rele(fromsnap, FTAG);
		dsl_dataset_rele(tosnap, FTAG);
		dsl_pool_rele(dp, FTAG);
		return (SET_ERROR(EXDEV));
	}

	fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
	dsl_dataset_rele(fromsnap, FTAG);

	dsl_dataset_long_hold(tosnap, FTAG);
	dsl_pool_rele(dp, FTAG);

	da.da_fp = fp;
	da.da_offp = offp;
	da.da_ddr.ddr_type = DDR_NONE;
	da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
	da.da_err = 0;

	/*
	 * Since zfs diff only looks at dnodes which are stored in plaintext
	 * (other than bonus buffers), we don't technically need to decrypt
	 * the dataset to perform this operation. However, the command line
	 * utility will still fail if the keys are not loaded because the
	 * dataset isn't mounted and because it will fail when it attempts to
	 * call the ZFS_IOC_OBJ_TO_STATS ioctl.