xref: /titanic_50/usr/src/uts/common/fs/zfs/bpobj.c (revision 3fc1e28905f8d0b151f1f359d523492bed5a20f2) 
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2012 by Delphix. All rights reserved.
24  */
25 
26 #include <sys/bpobj.h>
27 #include <sys/zfs_context.h>
28 #include <sys/refcount.h>
29 #include <sys/dsl_pool.h>
30 #include <sys/zfeature.h>
31 #include <sys/zap.h>
32 
33 /*
34  * Return an empty bpobj, preferably the empty dummy one (dp_empty_bpobj).
35  */
36 uint64_t
37 bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx)
38 {
39 	zfeature_info_t *empty_bpobj_feat =
40 	    &spa_feature_table[SPA_FEATURE_EMPTY_BPOBJ];
41 	spa_t *spa = dmu_objset_spa(os);
42 	dsl_pool_t *dp = dmu_objset_pool(os);
43 
44 	if (spa_feature_is_enabled(spa, empty_bpobj_feat)) {
45 		if (!spa_feature_is_active(spa, empty_bpobj_feat)) {
46 			ASSERT0(dp->dp_empty_bpobj);
47 			dp->dp_empty_bpobj =
48 			    bpobj_alloc(os, SPA_MAXBLOCKSIZE, tx);
49 			VERIFY(zap_add(os,
50 			    DMU_POOL_DIRECTORY_OBJECT,
51 			    DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
52 			    &dp->dp_empty_bpobj, tx) == 0);
53 		}
54 		spa_feature_incr(spa, empty_bpobj_feat, tx);
55 		ASSERT(dp->dp_empty_bpobj != 0);
56 		return (dp->dp_empty_bpobj);
57 	} else {
58 		return (bpobj_alloc(os, blocksize, tx));
59 	}
60 }
61 
62 void
63 bpobj_decr_empty(objset_t *os, dmu_tx_t *tx)
64 {
65 	zfeature_info_t *empty_bpobj_feat =
66 	    &spa_feature_table[SPA_FEATURE_EMPTY_BPOBJ];
67 	dsl_pool_t *dp = dmu_objset_pool(os);
68 
69 	spa_feature_decr(dmu_objset_spa(os), empty_bpobj_feat, tx);
70 	if (!spa_feature_is_active(dmu_objset_spa(os), empty_bpobj_feat)) {
71 		VERIFY3U(0, ==, zap_remove(dp->dp_meta_objset,
72 		    DMU_POOL_DIRECTORY_OBJECT,
73 		    DMU_POOL_EMPTY_BPOBJ, tx));
74 		VERIFY3U(0, ==, dmu_object_free(os, dp->dp_empty_bpobj, tx));
75 		dp->dp_empty_bpobj = 0;
76 	}
77 }
78 
79 uint64_t
80 bpobj_alloc(objset_t *os, int blocksize, dmu_tx_t *tx)
81 {
82 	int size;
83 
84 	if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_BPOBJ_ACCOUNT)
85 		size = BPOBJ_SIZE_V0;
86 	else if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_DEADLISTS)
87 		size = BPOBJ_SIZE_V1;
88 	else
89 		size = sizeof (bpobj_phys_t);
90 
91 	return (dmu_object_alloc(os, DMU_OT_BPOBJ, blocksize,
92 	    DMU_OT_BPOBJ_HDR, size, tx));
93 }
94 
95 void
96 bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx)
97 {
98 	int64_t i;
99 	bpobj_t bpo;
100 	dmu_object_info_t doi;
101 	int epb;
102 	dmu_buf_t *dbuf = NULL;
103 
104 	ASSERT(obj != dmu_objset_pool(os)->dp_empty_bpobj);
105 	VERIFY3U(0, ==, bpobj_open(&bpo, os, obj));
106 
107 	mutex_enter(&bpo.bpo_lock);
108 
109 	if (!bpo.bpo_havesubobj || bpo.bpo_phys->bpo_subobjs == 0)
110 		goto out;
111 
112 	VERIFY3U(0, ==, dmu_object_info(os, bpo.bpo_phys->bpo_subobjs, &doi));
113 	epb = doi.doi_data_block_size / sizeof (uint64_t);
114 
115 	for (i = bpo.bpo_phys->bpo_num_subobjs - 1; i >= 0; i--) {
116 		uint64_t *objarray;
117 		uint64_t offset, blkoff;
118 
119 		offset = i * sizeof (uint64_t);
120 		blkoff = P2PHASE(i, epb);
121 
122 		if (dbuf == NULL || dbuf->db_offset > offset) {
123 			if (dbuf)
124 				dmu_buf_rele(dbuf, FTAG);
125 			VERIFY3U(0, ==, dmu_buf_hold(os,
126 			    bpo.bpo_phys->bpo_subobjs, offset, FTAG, &dbuf, 0));
127 		}
128 
129 		ASSERT3U(offset, >=, dbuf->db_offset);
130 		ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);
131 
132 		objarray = dbuf->db_data;
133 		bpobj_free(os, objarray[blkoff], tx);
134 	}
135 	if (dbuf) {
136 		dmu_buf_rele(dbuf, FTAG);
137 		dbuf = NULL;
138 	}
139 	VERIFY3U(0, ==, dmu_object_free(os, bpo.bpo_phys->bpo_subobjs, tx));
140 
141 out:
142 	mutex_exit(&bpo.bpo_lock);
143 	bpobj_close(&bpo);
144 
145 	VERIFY3U(0, ==, dmu_object_free(os, obj, tx));
146 }
147 
148 int
149 bpobj_open(bpobj_t *bpo, objset_t *os, uint64_t object)
150 {
151 	dmu_object_info_t doi;
152 	int err;
153 
154 	err = dmu_object_info(os, object, &doi);
155 	if (err)
156 		return (err);
157 
158 	bzero(bpo, sizeof (*bpo));
159 	mutex_init(&bpo->bpo_lock, NULL, MUTEX_DEFAULT, NULL);
160 
161 	ASSERT(bpo->bpo_dbuf == NULL);
162 	ASSERT(bpo->bpo_phys == NULL);
163 	ASSERT(object != 0);
164 	ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ);
165 	ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_BPOBJ_HDR);
166 
167 	err = dmu_bonus_hold(os, object, bpo, &bpo->bpo_dbuf);
168 	if (err)
169 		return (err);
170 
171 	bpo->bpo_os = os;
172 	bpo->bpo_object = object;
173 	bpo->bpo_epb = doi.doi_data_block_size >> SPA_BLKPTRSHIFT;
174 	bpo->bpo_havecomp = (doi.doi_bonus_size > BPOBJ_SIZE_V0);
175 	bpo->bpo_havesubobj = (doi.doi_bonus_size > BPOBJ_SIZE_V1);
176 	bpo->bpo_phys = bpo->bpo_dbuf->db_data;
177 	return (0);
178 }
179 
180 void
181 bpobj_close(bpobj_t *bpo)
182 {
183 	/* Lame workaround for closing a bpobj that was never opened. */
184 	if (bpo->bpo_object == 0)
185 		return;
186 
187 	dmu_buf_rele(bpo->bpo_dbuf, bpo);
188 	if (bpo->bpo_cached_dbuf != NULL)
189 		dmu_buf_rele(bpo->bpo_cached_dbuf, bpo);
190 	bpo->bpo_dbuf = NULL;
191 	bpo->bpo_phys = NULL;
192 	bpo->bpo_cached_dbuf = NULL;
193 	bpo->bpo_object = 0;
194 
195 	mutex_destroy(&bpo->bpo_lock);
196 }
197 
198 static int
199 bpobj_iterate_impl(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx,
200     boolean_t free)
201 {
202 	dmu_object_info_t doi;
203 	int epb;
204 	int64_t i;
205 	int err = 0;
206 	dmu_buf_t *dbuf = NULL;
207 
208 	mutex_enter(&bpo->bpo_lock);
209 
210 	if (free)
211 		dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
212 
213 	for (i = bpo->bpo_phys->bpo_num_blkptrs - 1; i >= 0; i--) {
214 		blkptr_t *bparray;
215 		blkptr_t *bp;
216 		uint64_t offset, blkoff;
217 
218 		offset = i * sizeof (blkptr_t);
219 		blkoff = P2PHASE(i, bpo->bpo_epb);
220 
221 		if (dbuf == NULL || dbuf->db_offset > offset) {
222 			if (dbuf)
223 				dmu_buf_rele(dbuf, FTAG);
224 			err = dmu_buf_hold(bpo->bpo_os, bpo->bpo_object, offset,
225 			    FTAG, &dbuf, 0);
226 			if (err)
227 				break;
228 		}
229 
230 		ASSERT3U(offset, >=, dbuf->db_offset);
231 		ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);
232 
233 		bparray = dbuf->db_data;
234 		bp = &bparray[blkoff];
235 		err = func(arg, bp, tx);
236 		if (err)
237 			break;
238 		if (free) {
239 			bpo->bpo_phys->bpo_bytes -=
240 			    bp_get_dsize_sync(dmu_objset_spa(bpo->bpo_os), bp);
241 			ASSERT3S(bpo->bpo_phys->bpo_bytes, >=, 0);
242 			if (bpo->bpo_havecomp) {
243 				bpo->bpo_phys->bpo_comp -= BP_GET_PSIZE(bp);
244 				bpo->bpo_phys->bpo_uncomp -= BP_GET_UCSIZE(bp);
245 			}
246 			bpo->bpo_phys->bpo_num_blkptrs--;
247 			ASSERT3S(bpo->bpo_phys->bpo_num_blkptrs, >=, 0);
248 		}
249 	}
250 	if (dbuf) {
251 		dmu_buf_rele(dbuf, FTAG);
252 		dbuf = NULL;
253 	}
254 	if (free) {
255 		i++;
256 		VERIFY3U(0, ==, dmu_free_range(bpo->bpo_os, bpo->bpo_object,
257 		    i * sizeof (blkptr_t), -1ULL, tx));
258 	}
259 	if (err || !bpo->bpo_havesubobj || bpo->bpo_phys->bpo_subobjs == 0)
260 		goto out;
261 
262 	ASSERT(bpo->bpo_havecomp);
263 	err = dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi);
264 	if (err) {
265 		mutex_exit(&bpo->bpo_lock);
266 		return (err);
267 	}
268 	epb = doi.doi_data_block_size / sizeof (uint64_t);
269 
270 	for (i = bpo->bpo_phys->bpo_num_subobjs - 1; i >= 0; i--) {
271 		uint64_t *objarray;
272 		uint64_t offset, blkoff;
273 		bpobj_t sublist;
274 		uint64_t used_before, comp_before, uncomp_before;
275 		uint64_t used_after, comp_after, uncomp_after;
276 
277 		offset = i * sizeof (uint64_t);
278 		blkoff = P2PHASE(i, epb);
279 
280 		if (dbuf == NULL || dbuf->db_offset > offset) {
281 			if (dbuf)
282 				dmu_buf_rele(dbuf, FTAG);
283 			err = dmu_buf_hold(bpo->bpo_os,
284 			    bpo->bpo_phys->bpo_subobjs, offset, FTAG, &dbuf, 0);
285 			if (err)
286 				break;
287 		}
288 
289 		ASSERT3U(offset, >=, dbuf->db_offset);
290 		ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);
291 
292 		objarray = dbuf->db_data;
293 		err = bpobj_open(&sublist, bpo->bpo_os, objarray[blkoff]);
294 		if (err)
295 			break;
296 		if (free) {
297 			err = bpobj_space(&sublist,
298 			    &used_before, &comp_before, &uncomp_before);
299 			if (err)
300 				break;
301 		}
302 		err = bpobj_iterate_impl(&sublist, func, arg, tx, free);
303 		if (free) {
304 			VERIFY3U(0, ==, bpobj_space(&sublist,
305 			    &used_after, &comp_after, &uncomp_after));
306 			bpo->bpo_phys->bpo_bytes -= used_before - used_after;
307 			ASSERT3S(bpo->bpo_phys->bpo_bytes, >=, 0);
308 			bpo->bpo_phys->bpo_comp -= comp_before - comp_after;
309 			bpo->bpo_phys->bpo_uncomp -=
310 			    uncomp_before - uncomp_after;
311 		}
312 
313 		bpobj_close(&sublist);
314 		if (err)
315 			break;
316 		if (free) {
317 			err = dmu_object_free(bpo->bpo_os,
318 			    objarray[blkoff], tx);
319 			if (err)
320 				break;
321 			bpo->bpo_phys->bpo_num_subobjs--;
322 			ASSERT3S(bpo->bpo_phys->bpo_num_subobjs, >=, 0);
323 		}
324 	}
325 	if (dbuf) {
326 		dmu_buf_rele(dbuf, FTAG);
327 		dbuf = NULL;
328 	}
329 	if (free) {
330 		VERIFY3U(0, ==, dmu_free_range(bpo->bpo_os,
331 		    bpo->bpo_phys->bpo_subobjs,
332 		    (i + 1) * sizeof (uint64_t), -1ULL, tx));
333 	}
334 
335 out:
336 	/* If there are no entries, there should be no bytes. */
337 	ASSERT(bpo->bpo_phys->bpo_num_blkptrs > 0 ||
338 	    (bpo->bpo_havesubobj && bpo->bpo_phys->bpo_num_subobjs > 0) ||
339 	    bpo->bpo_phys->bpo_bytes == 0);
340 
341 	mutex_exit(&bpo->bpo_lock);
342 	return (err);
343 }
344 
345 /*
346  * Iterate and remove the entries.  If func returns nonzero, iteration
347  * will stop and that entry will not be removed.
348  */
349 int
350 bpobj_iterate(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx)
351 {
352 	return (bpobj_iterate_impl(bpo, func, arg, tx, B_TRUE));
353 }
354 
355 /*
356  * Iterate the entries.  If func returns nonzero, iteration will stop.
357  */
358 int
359 bpobj_iterate_nofree(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx)
360 {
361 	return (bpobj_iterate_impl(bpo, func, arg, tx, B_FALSE));
362 }
363 
364 void
365 bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx)
366 {
367 	bpobj_t subbpo;
368 	uint64_t used, comp, uncomp, subsubobjs;
369 
370 	ASSERT(bpo->bpo_havesubobj);
371 	ASSERT(bpo->bpo_havecomp);
372 	ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);
373 
374 	if (subobj == dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj) {
375 		bpobj_decr_empty(bpo->bpo_os, tx);
376 		return;
377 	}
378 
379 	VERIFY3U(0, ==, bpobj_open(&subbpo, bpo->bpo_os, subobj));
380 	VERIFY3U(0, ==, bpobj_space(&subbpo, &used, &comp, &uncomp));
381 
382 	if (used == 0) {
383 		/* No point in having an empty subobj. */
384 		bpobj_close(&subbpo);
385 		bpobj_free(bpo->bpo_os, subobj, tx);
386 		return;
387 	}
388 
389 	dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
390 	if (bpo->bpo_phys->bpo_subobjs == 0) {
391 		bpo->bpo_phys->bpo_subobjs = dmu_object_alloc(bpo->bpo_os,
392 		    DMU_OT_BPOBJ_SUBOBJ, SPA_MAXBLOCKSIZE, DMU_OT_NONE, 0, tx);
393 	}
394 
395 	mutex_enter(&bpo->bpo_lock);
396 	dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs,
397 	    bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj),
398 	    sizeof (subobj), &subobj, tx);
399 	bpo->bpo_phys->bpo_num_subobjs++;
400 
401 	/*
402 	 * If subobj has only one block of subobjs, then move subobj's
403 	 * subobjs to bpo's subobj list directly.  This reduces
404 	 * recursion in bpobj_iterate due to nested subobjs.
405 	 */
406 	subsubobjs = subbpo.bpo_phys->bpo_subobjs;
407 	if (subsubobjs != 0) {
408 		dmu_object_info_t doi;
409 
410 		VERIFY3U(0, ==, dmu_object_info(bpo->bpo_os, subsubobjs, &doi));
411 		if (doi.doi_max_offset == doi.doi_data_block_size) {
412 			dmu_buf_t *subdb;
413 			uint64_t numsubsub = subbpo.bpo_phys->bpo_num_subobjs;
414 
415 			VERIFY3U(0, ==, dmu_buf_hold(bpo->bpo_os, subsubobjs,
416 			    0, FTAG, &subdb, 0));
417 			dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs,
418 			    bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj),
419 			    numsubsub * sizeof (subobj), subdb->db_data, tx);
420 			dmu_buf_rele(subdb, FTAG);
421 			bpo->bpo_phys->bpo_num_subobjs += numsubsub;
422 
423 			dmu_buf_will_dirty(subbpo.bpo_dbuf, tx);
424 			subbpo.bpo_phys->bpo_subobjs = 0;
425 			VERIFY3U(0, ==, dmu_object_free(bpo->bpo_os,
426 			    subsubobjs, tx));
427 		}
428 	}
429 	bpo->bpo_phys->bpo_bytes += used;
430 	bpo->bpo_phys->bpo_comp += comp;
431 	bpo->bpo_phys->bpo_uncomp += uncomp;
432 	mutex_exit(&bpo->bpo_lock);
433 
434 	bpobj_close(&subbpo);
435 }
436 
437 void
438 bpobj_enqueue(bpobj_t *bpo, const blkptr_t *bp, dmu_tx_t *tx)
439 {
440 	blkptr_t stored_bp = *bp;
441 	uint64_t offset;
442 	int blkoff;
443 	blkptr_t *bparray;
444 
445 	ASSERT(!BP_IS_HOLE(bp));
446 	ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);
447 
448 	/* We never need the fill count. */
449 	stored_bp.blk_fill = 0;
450 
451 	/* The bpobj will compress better if we can leave off the checksum */
452 	if (!BP_GET_DEDUP(bp))
453 		bzero(&stored_bp.blk_cksum, sizeof (stored_bp.blk_cksum));
454 
455 	mutex_enter(&bpo->bpo_lock);
456 
457 	offset = bpo->bpo_phys->bpo_num_blkptrs * sizeof (stored_bp);
458 	blkoff = P2PHASE(bpo->bpo_phys->bpo_num_blkptrs, bpo->bpo_epb);
459 
460 	if (bpo->bpo_cached_dbuf == NULL ||
461 	    offset < bpo->bpo_cached_dbuf->db_offset ||
462 	    offset >= bpo->bpo_cached_dbuf->db_offset +
463 	    bpo->bpo_cached_dbuf->db_size) {
464 		if (bpo->bpo_cached_dbuf)
465 			dmu_buf_rele(bpo->bpo_cached_dbuf, bpo);
466 		VERIFY3U(0, ==, dmu_buf_hold(bpo->bpo_os, bpo->bpo_object,
467 		    offset, bpo, &bpo->bpo_cached_dbuf, 0));
468 	}
469 
470 	dmu_buf_will_dirty(bpo->bpo_cached_dbuf, tx);
471 	bparray = bpo->bpo_cached_dbuf->db_data;
472 	bparray[blkoff] = stored_bp;
473 
474 	dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
475 	bpo->bpo_phys->bpo_num_blkptrs++;
476 	bpo->bpo_phys->bpo_bytes +=
477 	    bp_get_dsize_sync(dmu_objset_spa(bpo->bpo_os), bp);
478 	if (bpo->bpo_havecomp) {
479 		bpo->bpo_phys->bpo_comp += BP_GET_PSIZE(bp);
480 		bpo->bpo_phys->bpo_uncomp += BP_GET_UCSIZE(bp);
481 	}
482 	mutex_exit(&bpo->bpo_lock);
483 }
484 
485 struct space_range_arg {
486 	spa_t *spa;
487 	uint64_t mintxg;
488 	uint64_t maxtxg;
489 	uint64_t used;
490 	uint64_t comp;
491 	uint64_t uncomp;
492 };
493 
494 /* ARGSUSED */
495 static int
496 space_range_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
497 {
498 	struct space_range_arg *sra = arg;
499 
500 	if (bp->blk_birth > sra->mintxg && bp->blk_birth <= sra->maxtxg) {
501 		if (dsl_pool_sync_context(spa_get_dsl(sra->spa)))
502 			sra->used += bp_get_dsize_sync(sra->spa, bp);
503 		else
504 			sra->used += bp_get_dsize(sra->spa, bp);
505 		sra->comp += BP_GET_PSIZE(bp);
506 		sra->uncomp += BP_GET_UCSIZE(bp);
507 	}
508 	return (0);
509 }
510 
511 int
512 bpobj_space(bpobj_t *bpo, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
513 {
514 	mutex_enter(&bpo->bpo_lock);
515 
516 	*usedp = bpo->bpo_phys->bpo_bytes;
517 	if (bpo->bpo_havecomp) {
518 		*compp = bpo->bpo_phys->bpo_comp;
519 		*uncompp = bpo->bpo_phys->bpo_uncomp;
520 		mutex_exit(&bpo->bpo_lock);
521 		return (0);
522 	} else {
523 		mutex_exit(&bpo->bpo_lock);
524 		return (bpobj_space_range(bpo, 0, UINT64_MAX,
525 		    usedp, compp, uncompp));
526 	}
527 }
528 
529 /*
530  * Return the amount of space in the bpobj which is:
531  * mintxg < blk_birth <= maxtxg
532  */
533 int
534 bpobj_space_range(bpobj_t *bpo, uint64_t mintxg, uint64_t maxtxg,
535     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
536 {
537 	struct space_range_arg sra = { 0 };
538 	int err;
539 
540 	/*
541 	 * As an optimization, if they want the whole txg range, just
542 	 * get bpo_bytes rather than iterating over the bps.
543 	 */
544 	if (mintxg < TXG_INITIAL && maxtxg == UINT64_MAX && bpo->bpo_havecomp)
545 		return (bpobj_space(bpo, usedp, compp, uncompp));
546 
547 	sra.spa = dmu_objset_spa(bpo->bpo_os);
548 	sra.mintxg = mintxg;
549 	sra.maxtxg = maxtxg;
550 
551 	err = bpobj_iterate_nofree(bpo, space_range_cb, &sra, NULL);
552 	*usedp = sra.used;
553 	*compp = sra.comp;
554 	*uncompp = sra.uncomp;
555 	return (err);
556 }
557