1 files changed, 606 insertions, 0 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
new file mode 100644
index 000000000000..bbdd765214fc
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
@@ -0,0 +1,606 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
+ * Copyright (c) 2014 Integros [integros.com]
+ * Copyright (c) 2017 Datto Inc.
+ */
+
+#include <sys/bpobj.h>
+#include <sys/zfs_context.h>
+#include <sys/refcount.h>
+#include <sys/dsl_pool.h>
+#include <sys/zfeature.h>
+#include <sys/zap.h>
+
+/*
+ * Return an empty bpobj, preferably the empty dummy one (dp_empty_bpobj).
+ */
+uint64_t
+bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx)
+{
+	spa_t *spa = dmu_objset_spa(os);
+	dsl_pool_t *dp = dmu_objset_pool(os);
+
+	if (spa_feature_is_enabled(spa, SPA_FEATURE_EMPTY_BPOBJ)) {
+		if (!spa_feature_is_active(spa, SPA_FEATURE_EMPTY_BPOBJ)) {
+			ASSERT0(dp->dp_empty_bpobj);
+			dp->dp_empty_bpobj =
+			    bpobj_alloc(os, SPA_OLD_MAXBLOCKSIZE, tx);
+			VERIFY(zap_add(os,
+			    DMU_POOL_DIRECTORY_OBJECT,
+			    DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
+			    &dp->dp_empty_bpobj, tx) == 0);
+		}
+		spa_feature_incr(spa, SPA_FEATURE_EMPTY_BPOBJ, tx);
+		ASSERT(dp->dp_empty_bpobj != 0);
+		return (dp->dp_empty_bpobj);
+	} else {
+		return (bpobj_alloc(os, blocksize, tx));
+	}
+}
+
+void
+bpobj_decr_empty(objset_t *os, dmu_tx_t *tx)
+{
+	dsl_pool_t *dp = dmu_objset_pool(os);
+
+	spa_feature_decr(dmu_objset_spa(os), SPA_FEATURE_EMPTY_BPOBJ, tx);
+	if (!spa_feature_is_active(dmu_objset_spa(os),
+	    SPA_FEATURE_EMPTY_BPOBJ)) {
+		VERIFY3U(0, ==, zap_remove(dp->dp_meta_objset,
+		    DMU_POOL_DIRECTORY_OBJECT,
+		    DMU_POOL_EMPTY_BPOBJ, tx));
+		VERIFY3U(0, ==, dmu_object_free(os, dp->dp_empty_bpobj, tx));
+		dp->dp_empty_bpobj = 0;
+	}
+}
+
+uint64_t
+bpobj_alloc(objset_t *os, int blocksize, dmu_tx_t *tx)
+{
+	int size;
+
+	if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_BPOBJ_ACCOUNT)
+		size = BPOBJ_SIZE_V0;
+	else if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_DEADLISTS)
+		size = BPOBJ_SIZE_V1;
+	else
+		size = sizeof (bpobj_phys_t);
+
+	return (dmu_object_alloc(os, DMU_OT_BPOBJ, blocksize,
+	    DMU_OT_BPOBJ_HDR, size, tx));
+}
+
+void
+bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx)
+{
+	int64_t i;
+	bpobj_t bpo;
+	dmu_object_info_t doi;
+	int epb;
+	dmu_buf_t *dbuf = NULL;
+
+	ASSERT(obj != dmu_objset_pool(os)->dp_empty_bpobj);
+	VERIFY3U(0, ==, bpobj_open(&bpo, os, obj));
+
+	mutex_enter(&bpo.bpo_lock);
+
+	if (!bpo.bpo_havesubobj || bpo.bpo_phys->bpo_subobjs == 0)
+		goto out;
+
+	VERIFY3U(0, ==, dmu_object_info(os, bpo.bpo_phys->bpo_subobjs, &doi));
+	epb = doi.doi_data_block_size / sizeof (uint64_t);
+
+	for (i = bpo.bpo_phys->bpo_num_subobjs - 1; i >= 0; i--) {
+		uint64_t *objarray;
+		uint64_t offset, blkoff;
+
+		offset = i * sizeof (uint64_t);
+		blkoff = P2PHASE(i, epb);
+
+		if (dbuf == NULL || dbuf->db_offset > offset) {
+			if (dbuf)
+				dmu_buf_rele(dbuf, FTAG);
+			VERIFY3U(0, ==, dmu_buf_hold(os,
+			    bpo.bpo_phys->bpo_subobjs, offset, FTAG, &dbuf, 0));
+		}
+
+		ASSERT3U(offset, >=, dbuf->db_offset);
+		ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);
+
+		objarray = dbuf->db_data;
+		bpobj_free(os, objarray[blkoff], tx);
+	}
+	if (dbuf) {
+		dmu_buf_rele(dbuf, FTAG);
+		dbuf = NULL;
+	}
+	VERIFY3U(0, ==, dmu_object_free(os, bpo.bpo_phys->bpo_subobjs, tx));
+
+out:
+	mutex_exit(&bpo.bpo_lock);
+	bpobj_close(&bpo);
+
+	VERIFY3U(0, ==, dmu_object_free(os, obj, tx));
+}
+
+int
+bpobj_open(bpobj_t *bpo, objset_t *os, uint64_t object)
+{
+	dmu_object_info_t doi;
+	int err;
+
+	err = dmu_object_info(os, object, &doi);
+	if (err)
+		return (err);
+
+	bzero(bpo, sizeof (*bpo));
+	mutex_init(&bpo->bpo_lock, NULL, MUTEX_DEFAULT, NULL);
+
+	ASSERT(bpo->bpo_dbuf == NULL);
+	ASSERT(bpo->bpo_phys == NULL);
+	ASSERT(object != 0);
+	ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ);
+	ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_BPOBJ_HDR);
+
+	err = dmu_bonus_hold(os, object, bpo, &bpo->bpo_dbuf);
+	if (err)
+		return (err);
+
+	bpo->bpo_os = os;
+	bpo->bpo_object = object;
+	bpo->bpo_epb = doi.doi_data_block_size >> SPA_BLKPTRSHIFT;
+	bpo->bpo_havecomp = (doi.doi_bonus_size > BPOBJ_SIZE_V0);
+	bpo->bpo_havesubobj = (doi.doi_bonus_size > BPOBJ_SIZE_V1);
+	bpo->bpo_phys = bpo->bpo_dbuf->db_data;
+	return (0);
+}
+
+boolean_t
+bpobj_is_open(const bpobj_t *bpo)
+{
+	return (bpo->bpo_object != 0);
+}
+
+void
+bpobj_close(bpobj_t *bpo)
+{
+	/* Lame workaround for closing a bpobj that was never opened. */
+	if (bpo->bpo_object == 0)
+		return;
+
+	dmu_buf_rele(bpo->bpo_dbuf, bpo);
+	if (bpo->bpo_cached_dbuf != NULL)
+		dmu_buf_rele(bpo->bpo_cached_dbuf, bpo);
+	bpo->bpo_dbuf = NULL;
+	bpo->bpo_phys = NULL;
+	bpo->bpo_cached_dbuf = NULL;
+	bpo->bpo_object = 0;
+
+	mutex_destroy(&bpo->bpo_lock);
+}
+
+boolean_t
+bpobj_is_empty(bpobj_t *bpo)
+{
+	return (bpo->bpo_phys->bpo_num_blkptrs == 0 &&
+	    (!bpo->bpo_havesubobj || bpo->bpo_phys->bpo_num_subobjs == 0));
+}
+
+static int
+bpobj_iterate_impl(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx,
+    boolean_t free)
+{
+	dmu_object_info_t doi;
+	int epb;
+	int64_t i;
+	int err = 0;
+	dmu_buf_t *dbuf = NULL;
+
+	ASSERT(bpobj_is_open(bpo));
+	mutex_enter(&bpo->bpo_lock);
+
+	if (free)
+		dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
+
+	for (i = bpo->bpo_phys->bpo_num_blkptrs - 1; i >= 0; i--) {
+		blkptr_t *bparray;
+		blkptr_t *bp;
+		uint64_t offset, blkoff;
+
+		offset = i * sizeof (blkptr_t);
+		blkoff = P2PHASE(i, bpo->bpo_epb);
+
+		if (dbuf == NULL || dbuf->db_offset > offset) {
+			if (dbuf)
+				dmu_buf_rele(dbuf, FTAG);
+			err = dmu_buf_hold(bpo->bpo_os, bpo->bpo_object, offset,
+			    FTAG, &dbuf, 0);
+			if (err)
+				break;
+		}
+
+		ASSERT3U(offset, >=, dbuf->db_offset);
+		ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);
+
+		bparray = dbuf->db_data;
+		bp = &bparray[blkoff];
+		err = func(arg, bp, tx);
+		if (err)
+			break;
+		if (free) {
+			bpo->bpo_phys->bpo_bytes -=
+			    bp_get_dsize_sync(dmu_objset_spa(bpo->bpo_os), bp);
+			ASSERT3S(bpo->bpo_phys->bpo_bytes, >=, 0);
+			if (bpo->bpo_havecomp) {
+				bpo->bpo_phys->bpo_comp -= BP_GET_PSIZE(bp);
+				bpo->bpo_phys->bpo_uncomp -= BP_GET_UCSIZE(bp);
+			}
+			bpo->bpo_phys->bpo_num_blkptrs--;
+			ASSERT3S(bpo->bpo_phys->bpo_num_blkptrs, >=, 0);
+		}
+	}
+	if (dbuf) {
+		dmu_buf_rele(dbuf, FTAG);
+		dbuf = NULL;
+	}
+	if (free) {
+		VERIFY3U(0, ==, dmu_free_range(bpo->bpo_os, bpo->bpo_object,
+		    (i + 1) * sizeof (blkptr_t), -1ULL, tx));
+	}
+	if (err || !bpo->bpo_havesubobj || bpo->bpo_phys->bpo_subobjs == 0)
+		goto out;
+
+	ASSERT(bpo->bpo_havecomp);
+	err = dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi);
+	if (err) {
+		mutex_exit(&bpo->bpo_lock);
+		return (err);
+	}
+	ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ_SUBOBJ);
+	epb = doi.doi_data_block_size / sizeof (uint64_t);
+
+	for (i = bpo->bpo_phys->bpo_num_subobjs - 1; i >= 0; i--) {
+		uint64_t *objarray;
+		uint64_t offset, blkoff;
+		bpobj_t sublist;
+		uint64_t used_before, comp_before, uncomp_before;
+		uint64_t used_after, comp_after, uncomp_after;
+
+		offset = i * sizeof (uint64_t);
+		blkoff = P2PHASE(i, epb);
+
+		if (dbuf == NULL || dbuf->db_offset > offset) {
+			if (dbuf)
+				dmu_buf_rele(dbuf, FTAG);
+			err = dmu_buf_hold(bpo->bpo_os,
+			    bpo->bpo_phys->bpo_subobjs, offset, FTAG, &dbuf, 0);
+			if (err)
+				break;
+		}
+
+		ASSERT3U(offset, >=, dbuf->db_offset);
+		ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);
+
+		objarray = dbuf->db_data;
+		err = bpobj_open(&sublist, bpo->bpo_os, objarray[blkoff]);
+		if (err)
+			break;
+		if (free) {
+			err = bpobj_space(&sublist,
+			    &used_before, &comp_before, &uncomp_before);
+			if (err != 0) {
+				bpobj_close(&sublist);
+				break;
+			}
+		}
+		err = bpobj_iterate_impl(&sublist, func, arg, tx, free);
+		if (free) {
+			VERIFY3U(0, ==, bpobj_space(&sublist,
+			    &used_after, &comp_after, &uncomp_after));
+			bpo->bpo_phys->bpo_bytes -= used_before - used_after;
+			ASSERT3S(bpo->bpo_phys->bpo_bytes, >=, 0);
+			bpo->bpo_phys->bpo_comp -= comp_before - comp_after;
+			bpo->bpo_phys->bpo_uncomp -=
+			    uncomp_before - uncomp_after;
+		}
+
+		bpobj_close(&sublist);
+		if (err)
+			break;
+		if (free) {
+			err = dmu_object_free(bpo->bpo_os,
+			    objarray[blkoff], tx);
+			if (err)
+				break;
+			bpo->bpo_phys->bpo_num_subobjs--;
+			ASSERT3S(bpo->bpo_phys->bpo_num_subobjs, >=, 0);
+		}
+	}
+	if (dbuf) {
+		dmu_buf_rele(dbuf, FTAG);
+		dbuf = NULL;
+	}
+	if (free) {
+		VERIFY3U(0, ==, dmu_free_range(bpo->bpo_os,
+		    bpo->bpo_phys->bpo_subobjs,
+		    (i + 1) * sizeof (uint64_t), -1ULL, tx));
+	}
+
+out:
+	/* If there are no entries, there should be no bytes. */
+	if (bpobj_is_empty(bpo)) {
+		ASSERT0(bpo->bpo_phys->bpo_bytes);
+		ASSERT0(bpo->bpo_phys->bpo_comp);
+		ASSERT0(bpo->bpo_phys->bpo_uncomp);
+	}
+
+	mutex_exit(&bpo->bpo_lock);
+	return (err);
+}
+
+/*
+ * Iterate and remove the entries.  If func returns nonzero, iteration
+ * will stop and that entry will not be removed.
+ */
+int
+bpobj_iterate(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx)
+{
+	return (bpobj_iterate_impl(bpo, func, arg, tx, B_TRUE));
+}
+
+/*
+ * Iterate the entries.  If func returns nonzero, iteration will stop.
+ */
+int
+bpobj_iterate_nofree(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx)
+{
+	return (bpobj_iterate_impl(bpo, func, arg, tx, B_FALSE));
+}
+
+void
+bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx)
+{
+	bpobj_t subbpo;
+	uint64_t used, comp, uncomp, subsubobjs;
+
+	ASSERT(bpobj_is_open(bpo));
+	ASSERT(subobj != 0);
+	ASSERT(bpo->bpo_havesubobj);
+	ASSERT(bpo->bpo_havecomp);
+	ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);
+
+	if (subobj == dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj) {
+		bpobj_decr_empty(bpo->bpo_os, tx);
+		return;
+	}
+
+	VERIFY3U(0, ==, bpobj_open(&subbpo, bpo->bpo_os, subobj));
+	VERIFY3U(0, ==, bpobj_space(&subbpo, &used, &comp, &uncomp));
+
+	if (bpobj_is_empty(&subbpo)) {
+		/* No point in having an empty subobj. */
+		bpobj_close(&subbpo);
+		bpobj_free(bpo->bpo_os, subobj, tx);
+		return;
+	}
+
+	mutex_enter(&bpo->bpo_lock);
+	dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
+	if (bpo->bpo_phys->bpo_subobjs == 0) {
+		bpo->bpo_phys->bpo_subobjs = dmu_object_alloc(bpo->bpo_os,
+		    DMU_OT_BPOBJ_SUBOBJ, SPA_OLD_MAXBLOCKSIZE,
+		    DMU_OT_NONE, 0, tx);
+	}
+
+	dmu_object_info_t doi;
+	ASSERT0(dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi));
+	ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ_SUBOBJ);
+
+	dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs,
+	    bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj),
+	    sizeof (subobj), &subobj, tx);
+	bpo->bpo_phys->bpo_num_subobjs++;
+
+	/*
+	 * If subobj has only one block of subobjs, then move subobj's
+	 * subobjs to bpo's subobj list directly.  This reduces
+	 * recursion in bpobj_iterate due to nested subobjs.
+	 */
+	subsubobjs = subbpo.bpo_phys->bpo_subobjs;
+	if (subsubobjs != 0) {
+		dmu_object_info_t doi;
+
+		VERIFY3U(0, ==, dmu_object_info(bpo->bpo_os, subsubobjs, &doi));
+		if (doi.doi_max_offset == doi.doi_data_block_size) {
+			dmu_buf_t *subdb;
+			uint64_t numsubsub = subbpo.bpo_phys->bpo_num_subobjs;
+
+			VERIFY3U(0, ==, dmu_buf_hold(bpo->bpo_os, subsubobjs,
+			    0, FTAG, &subdb, 0));
+			/*
+			 * Make sure that we are not asking dmu_write()
+			 * to write more data than we have in our buffer.
+			 */
+			VERIFY3U(subdb->db_size, >=,
+			    numsubsub * sizeof (subobj));
+			dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs,
+			    bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj),
+			    numsubsub * sizeof (subobj), subdb->db_data, tx);
+			dmu_buf_rele(subdb, FTAG);
+			bpo->bpo_phys->bpo_num_subobjs += numsubsub;
+
+			dmu_buf_will_dirty(subbpo.bpo_dbuf, tx);
+			subbpo.bpo_phys->bpo_subobjs = 0;
+			VERIFY3U(0, ==, dmu_object_free(bpo->bpo_os,
+			    subsubobjs, tx));
+		}
+	}
+	bpo->bpo_phys->bpo_bytes += used;
+	bpo->bpo_phys->bpo_comp += comp;
+	bpo->bpo_phys->bpo_uncomp += uncomp;
+	mutex_exit(&bpo->bpo_lock);
+
+	bpobj_close(&subbpo);
+}
+
+void
+bpobj_enqueue(bpobj_t *bpo, const blkptr_t *bp, dmu_tx_t *tx)
+{
+	blkptr_t stored_bp = *bp;
+	uint64_t offset;
+	int blkoff;
+	blkptr_t *bparray;
+
+	ASSERT(bpobj_is_open(bpo));
+	ASSERT(!BP_IS_HOLE(bp));
+	ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);
+
+	if (BP_IS_EMBEDDED(bp)) {
+		/*
+		 * The bpobj will compress better without the payload.
+		 *
+		 * Note that we store EMBEDDED bp's because they have an
+		 * uncompressed size, which must be accounted for.  An
+		 * alternative would be to add their size to bpo_uncomp
+		 * without storing the bp, but that would create additional
+		 * complications: bpo_uncomp would be inconsistent with the
+		 * set of BP's stored, and bpobj_iterate() wouldn't visit
+		 * all the space accounted for in the bpobj.
+		 */
+		bzero(&stored_bp, sizeof (stored_bp));
+		stored_bp.blk_prop = bp->blk_prop;
+		stored_bp.blk_birth = bp->blk_birth;
+	} else if (!BP_GET_DEDUP(bp)) {
+		/* The bpobj will compress better without the checksum */
+		bzero(&stored_bp.blk_cksum, sizeof (stored_bp.blk_cksum));
+	}
+
+	/* We never need the fill count. */
+	stored_bp.blk_fill = 0;
+
+	mutex_enter(&bpo->bpo_lock);
+
+	offset = bpo->bpo_phys->bpo_num_blkptrs * sizeof (stored_bp);
+	blkoff = P2PHASE(bpo->bpo_phys->bpo_num_blkptrs, bpo->bpo_epb);
+
+	if (bpo->bpo_cached_dbuf == NULL ||
+	    offset < bpo->bpo_cached_dbuf->db_offset ||
+	    offset >= bpo->bpo_cached_dbuf->db_offset +
+	    bpo->bpo_cached_dbuf->db_size) {
+		if (bpo->bpo_cached_dbuf)
+			dmu_buf_rele(bpo->bpo_cached_dbuf, bpo);
+		VERIFY3U(0, ==, dmu_buf_hold(bpo->bpo_os, bpo->bpo_object,
+		    offset, bpo, &bpo->bpo_cached_dbuf, 0));
+	}
+
+	dmu_buf_will_dirty(bpo->bpo_cached_dbuf, tx);
+	bparray = bpo->bpo_cached_dbuf->db_data;
+	bparray[blkoff] = stored_bp;
+
+	dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
+	bpo->bpo_phys->bpo_num_blkptrs++;
+	bpo->bpo_phys->bpo_bytes +=
+	    bp_get_dsize_sync(dmu_objset_spa(bpo->bpo_os), bp);
+	if (bpo->bpo_havecomp) {
+		bpo->bpo_phys->bpo_comp += BP_GET_PSIZE(bp);
+		bpo->bpo_phys->bpo_uncomp += BP_GET_UCSIZE(bp);
+	}
+	mutex_exit(&bpo->bpo_lock);
+}
+
+struct space_range_arg {
+	spa_t *spa;
+	uint64_t mintxg;
+	uint64_t maxtxg;
+	uint64_t used;
+	uint64_t comp;
+	uint64_t uncomp;
+};
+
+/* ARGSUSED */
+static int
+space_range_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
+{
+	struct space_range_arg *sra = arg;
+
+	if (bp->blk_birth > sra->mintxg && bp->blk_birth <= sra->maxtxg) {
+		if (dsl_pool_sync_context(spa_get_dsl(sra->spa)))
+			sra->used += bp_get_dsize_sync(sra->spa, bp);
+		else
+			sra->used += bp_get_dsize(sra->spa, bp);
+		sra->comp += BP_GET_PSIZE(bp);
+		sra->uncomp += BP_GET_UCSIZE(bp);
+	}
+	return (0);
+}
+
+int
+bpobj_space(bpobj_t *bpo, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
+{
+	ASSERT(bpobj_is_open(bpo));
+	mutex_enter(&bpo->bpo_lock);
+
+	*usedp = bpo->bpo_phys->bpo_bytes;
+	if (bpo->bpo_havecomp) {
+		*compp = bpo->bpo_phys->bpo_comp;
+		*uncompp = bpo->bpo_phys->bpo_uncomp;
+		mutex_exit(&bpo->bpo_lock);
+		return (0);
+	} else {
+		mutex_exit(&bpo->bpo_lock);
+		return (bpobj_space_range(bpo, 0, UINT64_MAX,
+		    usedp, compp, uncompp));
+	}
+}
+
+/*
+ * Return the amount of space in the bpobj which is:
+ * mintxg < blk_birth <= maxtxg
+ */
+int
+bpobj_space_range(bpobj_t *bpo, uint64_t mintxg, uint64_t maxtxg,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
+{
+	struct space_range_arg sra = { 0 };
+	int err;
+
+	ASSERT(bpobj_is_open(bpo));
+
+	/*
+	 * As an optimization, if they want the whole txg range, just
+	 * get bpo_bytes rather than iterating over the bps.
+	 */
+	if (mintxg < TXG_INITIAL && maxtxg == UINT64_MAX && bpo->bpo_havecomp)
+		return (bpobj_space(bpo, usedp, compp, uncompp));
+
+	sra.spa = dmu_objset_spa(bpo->bpo_os);
+	sra.mintxg = mintxg;
+	sra.maxtxg = maxtxg;
+
+	err = bpobj_iterate_nofree(bpo, space_range_cb, &sra, NULL);
+	*usedp = sra.used;
+	*compp = sra.comp;
+	*uncompp = sra.uncomp;
+	return (err);
+}