51 #include <sys/zap.h>
56  * If zap_iterate_prefetch is set, we will prefetch the entire ZAP object
72  * Given that the ZAP entries aren't returned in a specific order, the only
86  * Enable ZAP shrinking. When enabled, empty sibling leaf blocks will be
93 static uint64_t zap_allocate_blocks(zap_t *zap, int nblocks);
110 fzap_upgrade(zap_t *zap, dmu_tx_t *tx, zap_flags_t flags)  in fzap_upgrade()  argument
112 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in fzap_upgrade()
113 	zap->zap_ismicro = FALSE;  in fzap_upgrade()
115 	zap->zap_dbu.dbu_evict_func_sync = zap_evict_sync;  in fzap_upgrade()
116 	zap->zap_dbu.dbu_evict_func_async = NULL;  in fzap_upgrade()
118 	mutex_init(&zap->zap_f.zap_num_entries_mtx, 0, MUTEX_DEFAULT, 0);  in fzap_upgrade()
119 	zap->zap_f.zap_block_shift = highbit64(zap->zap_dbuf->db_size) - 1;  in fzap_upgrade()
121 	zap_phys_t *zp = zap_f_phys(zap);  in fzap_upgrade()
126 	memset(zap->zap_dbuf->db_data, 0, zap->zap_dbuf->db_size);  in fzap_upgrade()
130 	zp->zap_ptrtbl.zt_shift = ZAP_EMBEDDED_PTRTBL_SHIFT(zap);  in fzap_upgrade()
135 	zp->zap_salt = zap->zap_salt;  in fzap_upgrade()
136 	zp->zap_normflags = zap->zap_normflags;  in fzap_upgrade()
141 		ZAP_EMBEDDED_PTRTBL_ENT(zap, i) = 1;  in fzap_upgrade()
147 	VERIFY0(dmu_buf_hold_by_dnode(zap->zap_dnode,  in fzap_upgrade()
148 	    1<<FZAP_BLOCK_SHIFT(zap), FTAG, &db, DMU_READ_NO_PREFETCH));  in fzap_upgrade()
161 zap_tryupgradedir(zap_t *zap, dmu_tx_t *tx)  in zap_tryupgradedir()  argument
163 	if (RW_WRITE_HELD(&zap->zap_rwlock))  in zap_tryupgradedir()
165 	if (rw_tryupgrade(&zap->zap_rwlock)) {  in zap_tryupgradedir()
166 		dmu_buf_will_dirty(zap->zap_dbuf, tx);  in zap_tryupgradedir()
177 zap_table_grow(zap_t *zap, zap_table_phys_t *tbl,  in zap_table_grow()  argument
182 	int bs = FZAP_BLOCK_SHIFT(zap);  in zap_table_grow()
186 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_table_grow()
193 		newblk = zap_allocate_blocks(zap, tbl->zt_numblks * 2);  in zap_table_grow()
196 		dmu_prefetch_by_dnode(zap->zap_dnode, 0,  in zap_table_grow()
207 	int err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_grow()
214 	VERIFY0(dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_grow()
221 	VERIFY0(dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_grow()
237 		(void) dmu_free_range(zap->zap_objset, zap->zap_object,  in zap_table_grow()
254 zap_table_store(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t val,  in zap_table_store()  argument
257 	int bs = FZAP_BLOCK_SHIFT(zap);  in zap_table_store()
259 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in zap_table_store()
269 	int err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_store()
281 		err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_store()
301 zap_table_load(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t *valp)  in zap_table_load()  argument
303 	int bs = FZAP_BLOCK_SHIFT(zap);  in zap_table_load()
305 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in zap_table_load()
311 	int err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_load()
326 		err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_table_load()
350 zap_grow_ptrtbl(zap_t *zap, dmu_tx_t *tx)  in zap_grow_ptrtbl()  argument
358 	if (zap_f_phys(zap)->zap_ptrtbl.zt_shift >= zap_hashbits(zap) - 2)  in zap_grow_ptrtbl()
361 	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {  in zap_grow_ptrtbl()
367 		ASSERT3U(zap_f_phys(zap)->zap_ptrtbl.zt_shift, ==,  in zap_grow_ptrtbl()
368 		    ZAP_EMBEDDED_PTRTBL_SHIFT(zap));  in zap_grow_ptrtbl()
369 		ASSERT0(zap_f_phys(zap)->zap_ptrtbl.zt_blk);  in zap_grow_ptrtbl()
371 		uint64_t newblk = zap_allocate_blocks(zap, 1);  in zap_grow_ptrtbl()
373 		int err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_grow_ptrtbl()
374 		    newblk << FZAP_BLOCK_SHIFT(zap), FTAG, &db_new,  in zap_grow_ptrtbl()
379 		zap_ptrtbl_transfer(&ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),  in zap_grow_ptrtbl()
380 		    db_new->db_data, 1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap));  in zap_grow_ptrtbl()
383 		zap_f_phys(zap)->zap_ptrtbl.zt_blk = newblk;  in zap_grow_ptrtbl()
384 		zap_f_phys(zap)->zap_ptrtbl.zt_numblks = 1;  in zap_grow_ptrtbl()
385 		zap_f_phys(zap)->zap_ptrtbl.zt_shift++;  in zap_grow_ptrtbl()
387 		ASSERT3U(1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift, ==,  in zap_grow_ptrtbl()
388 		    zap_f_phys(zap)->zap_ptrtbl.zt_numblks <<  in zap_grow_ptrtbl()
389 		    (FZAP_BLOCK_SHIFT(zap)-3));  in zap_grow_ptrtbl()
393 		return (zap_table_grow(zap, &zap_f_phys(zap)->zap_ptrtbl,  in zap_grow_ptrtbl()
399 zap_increment_num_entries(zap_t *zap, int delta, dmu_tx_t *tx)  in zap_increment_num_entries()  argument
401 	dmu_buf_will_dirty(zap->zap_dbuf, tx);  in zap_increment_num_entries()
402 	mutex_enter(&zap->zap_f.zap_num_entries_mtx);  in zap_increment_num_entries()
403 	ASSERT(delta > 0 || zap_f_phys(zap)->zap_num_entries >= -delta);  in zap_increment_num_entries()
404 	zap_f_phys(zap)->zap_num_entries += delta;  in zap_increment_num_entries()
405 	mutex_exit(&zap->zap_f.zap_num_entries_mtx);  in zap_increment_num_entries()
409 zap_allocate_blocks(zap_t *zap, int nblocks)  in zap_allocate_blocks()  argument
411 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_allocate_blocks()
412 	uint64_t newblk = zap_f_phys(zap)->zap_freeblk;  in zap_allocate_blocks()
413 	zap_f_phys(zap)->zap_freeblk += nblocks;  in zap_allocate_blocks()
427 zap_create_leaf(zap_t *zap, dmu_tx_t *tx)  in zap_create_leaf()  argument
429 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_create_leaf()
431 	uint64_t blkid = zap_allocate_blocks(zap, 1);  in zap_create_leaf()
434 	VERIFY0(dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_create_leaf()
435 	    blkid << FZAP_BLOCK_SHIFT(zap), NULL, &db,  in zap_create_leaf()
439 	 * Create the leaf structure and stash it on the dbuf. If zap was  in zap_create_leaf()
461 	zap_leaf_init(l, zap->zap_normflags != 0);  in zap_create_leaf()
463 	zap_f_phys(zap)->zap_num_leafs++;  in zap_create_leaf()
469 fzap_count(zap_t *zap, uint64_t *count)  in fzap_count()  argument
471 	ASSERT(!zap->zap_ismicro);  in fzap_count()
472 	mutex_enter(&zap->zap_f.zap_num_entries_mtx); /* unnecessary */  in fzap_count()
473 	*count = zap_f_phys(zap)->zap_num_entries;  in fzap_count()
474 	mutex_exit(&zap->zap_f.zap_num_entries_mtx);  in fzap_count()
536 zap_get_leaf_byblk(zap_t *zap, uint64_t blkid, dmu_tx_t *tx, krw_t lt,  in zap_get_leaf_byblk()  argument
541 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in zap_get_leaf_byblk()
553 	int bs = FZAP_BLOCK_SHIFT(zap);  in zap_get_leaf_byblk()
554 	int err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in zap_get_leaf_byblk()
559 	ASSERT3U(db->db_object, ==, zap->zap_object);  in zap_get_leaf_byblk()
586 zap_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t *valp)  in zap_idx_to_blk()  argument
588 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in zap_idx_to_blk()
590 	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {  in zap_idx_to_blk()
592 		    (1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift));  in zap_idx_to_blk()
593 		*valp = ZAP_EMBEDDED_PTRTBL_ENT(zap, idx);  in zap_idx_to_blk()
596 		return (zap_table_load(zap, &zap_f_phys(zap)->zap_ptrtbl,  in zap_idx_to_blk()
602 zap_set_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t blk, dmu_tx_t *tx)  in zap_set_idx_to_blk()  argument
605 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_set_idx_to_blk()
607 	if (zap_f_phys(zap)->zap_ptrtbl.zt_blk == 0) {  in zap_set_idx_to_blk()
608 		ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) = blk;  in zap_set_idx_to_blk()
611 		return (zap_table_store(zap, &zap_f_phys(zap)->zap_ptrtbl,  in zap_set_idx_to_blk()
617 zap_set_idx_range_to_blk(zap_t *zap, uint64_t idx, uint64_t nptrs, uint64_t blk,  in zap_set_idx_range_to_blk()  argument
620 	int bs = FZAP_BLOCK_SHIFT(zap);  in zap_set_idx_range_to_blk()
625 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_set_idx_range_to_blk()
632 		err = zap_idx_to_blk(zap, idx + i, &blk);  in zap_set_idx_range_to_blk()
639 		err = zap_set_idx_to_blk(zap, idx + i, blk, tx);  in zap_set_idx_range_to_blk()
651  * Each leaf has single range of entries (block pointers) in the ZAP ptrtbl.
658 check_sibling_ptrtbl_range(zap_t *zap, uint64_t prefix, uint64_t prefix_len)  in check_sibling_ptrtbl_range()  argument
660 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in check_sibling_ptrtbl_range()
663 	uint64_t idx = ZAP_HASH_IDX(h, zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in check_sibling_ptrtbl_range()
664 	uint64_t pref_diff = zap_f_phys(zap)->zap_ptrtbl.zt_shift - prefix_len;  in check_sibling_ptrtbl_range()
669 	ASSERT3U(idx+nptrs, <=, (1UL << zap_f_phys(zap)->zap_ptrtbl.zt_shift));  in check_sibling_ptrtbl_range()
671 	if (zap_idx_to_blk(zap, idx, &first) != 0)  in check_sibling_ptrtbl_range()
674 	if (zap_idx_to_blk(zap, idx + nptrs - 1, &last) != 0)  in check_sibling_ptrtbl_range()
683 zap_deref_leaf(zap_t *zap, uint64_t h, dmu_tx_t *tx, krw_t lt, zap_leaf_t **lp)  in zap_deref_leaf()  argument
687 	ASSERT(zap->zap_dbuf == NULL ||  in zap_deref_leaf()
688 	    zap_f_phys(zap) == zap->zap_dbuf->db_data);  in zap_deref_leaf()
690 	/* Reality check for corrupt zap objects (leaf or header). */  in zap_deref_leaf()
691 	if ((zap_f_phys(zap)->zap_block_type != ZBT_LEAF &&  in zap_deref_leaf()
692 	    zap_f_phys(zap)->zap_block_type != ZBT_HEADER) ||  in zap_deref_leaf()
693 	    zap_f_phys(zap)->zap_magic != ZAP_MAGIC) {  in zap_deref_leaf()
697 	uint64_t idx = ZAP_HASH_IDX(h, zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in zap_deref_leaf()
698 	int err = zap_idx_to_blk(zap, idx, &blk);  in zap_deref_leaf()
701 	err = zap_get_leaf_byblk(zap, blk, tx, lt, lp);  in zap_deref_leaf()
713 	zap_t *zap = zn->zn_zap;  in zap_expand_leaf()  local
718 	ASSERT3U(old_prefix_len, <=, zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in zap_expand_leaf()
719 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in zap_expand_leaf()
724 	if (zap_tryupgradedir(zap, tx) == 0 ||  in zap_expand_leaf()
725 	    old_prefix_len == zap_f_phys(zap)->zap_ptrtbl.zt_shift) {  in zap_expand_leaf()
727 		objset_t *os = zap->zap_objset;  in zap_expand_leaf()
728 		uint64_t object = zap->zap_object;  in zap_expand_leaf()
732 		zap_unlockdir(zap, tag);  in zap_expand_leaf()
735 		zap = zn->zn_zap;  in zap_expand_leaf()
738 		ASSERT(!zap->zap_ismicro);  in zap_expand_leaf()
741 		    zap_f_phys(zap)->zap_ptrtbl.zt_shift) {  in zap_expand_leaf()
742 			err = zap_grow_ptrtbl(zap, tx);  in zap_expand_leaf()
747 		err = zap_deref_leaf(zap, hash, tx, RW_WRITER, &l);  in zap_expand_leaf()
757 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_expand_leaf()
758 	ASSERT3U(old_prefix_len, <, zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in zap_expand_leaf()
762 	int prefix_diff = zap_f_phys(zap)->zap_ptrtbl.zt_shift -  in zap_expand_leaf()
770 		err = zap_idx_to_blk(zap, sibling + i, &blk);  in zap_expand_leaf()
776 	zap_leaf_t *nl = zap_create_leaf(zap, tx);  in zap_expand_leaf()
777 	zap_leaf_split(l, nl, zap->zap_normflags != 0);  in zap_expand_leaf()
781 		err = zap_set_idx_to_blk(zap, sibling + i, nl->l_blkid, tx);  in zap_expand_leaf()
803 	zap_t *zap = zn->zn_zap;  in zap_put_leaf_maybe_grow_ptrtbl()  local
804 	int shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;  in zap_put_leaf_maybe_grow_ptrtbl()
810 	if (leaffull || zap_f_phys(zap)->zap_ptrtbl.zt_nextblk) {  in zap_put_leaf_maybe_grow_ptrtbl()
815 		if (zap_tryupgradedir(zap, tx) == 0) {  in zap_put_leaf_maybe_grow_ptrtbl()
816 			objset_t *os = zap->zap_objset;  in zap_put_leaf_maybe_grow_ptrtbl()
817 			uint64_t zapobj = zap->zap_object;  in zap_put_leaf_maybe_grow_ptrtbl()
819 			zap_unlockdir(zap, tag);  in zap_put_leaf_maybe_grow_ptrtbl()
822 			zap = zn->zn_zap;  in zap_put_leaf_maybe_grow_ptrtbl()
828 		if (zap_f_phys(zap)->zap_ptrtbl.zt_shift == shift)  in zap_put_leaf_maybe_grow_ptrtbl()
829 			(void) zap_grow_ptrtbl(zap, tx);  in zap_put_leaf_maybe_grow_ptrtbl()
838 	/* Only allow directory zap to have longname */  in fzap_checkname()
920 	zap_t *zap = zn->zn_zap;  in fzap_add_cd()  local
922 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in fzap_add_cd()
923 	ASSERT(!zap->zap_ismicro);  in fzap_add_cd()
926 	err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);  in fzap_add_cd()
942 		zap_increment_num_entries(zap, 1, tx);  in fzap_add_cd()
945 		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */  in fzap_add_cd()
982 	zap_t *zap = zn->zn_zap;  in fzap_update()  local
984 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in fzap_update()
989 	err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);  in fzap_update()
1001 			zap_increment_num_entries(zap, 1, tx);  in fzap_update()
1008 		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */  in fzap_update()
1073 	zap_t *zap = zn->zn_zap;  in fzap_prefetch()  local
1076 	    zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in fzap_prefetch()
1077 	if (zap_idx_to_blk(zap, idx, &blk) != 0)  in fzap_prefetch()
1079 	int bs = FZAP_BLOCK_SHIFT(zap);  in fzap_prefetch()
1080 	dmu_prefetch_by_dnode(zap->zap_dnode, 0, blk << bs, 1 << bs,  in fzap_prefetch()
1305 fzap_cursor_retrieve(zap_t *zap, zap_cursor_t *zc, zap_attribute_t *za)  in fzap_cursor_retrieve()  argument
1316 	 * iterate over the entire ZAP object.  If there are multiple leaf  in fzap_cursor_retrieve()
1323 	    zc->zc_prefetch && zap_f_phys(zap)->zap_freeblk > 2) {  in fzap_cursor_retrieve()
1324 		dmu_prefetch_by_dnode(zap->zap_dnode, 0, 0,  in fzap_cursor_retrieve()
1325 		    zap_f_phys(zap)->zap_freeblk << FZAP_BLOCK_SHIFT(zap),  in fzap_cursor_retrieve()
1346 		err = zap_deref_leaf(zap, zc->zc_hash, NULL, RW_READER,  in fzap_cursor_retrieve()
1387 		err = zap_entry_read_name(zap, &zeh,  in fzap_cursor_retrieve()
1393 		    NULL, za->za_name, zap);  in fzap_cursor_retrieve()
1400 zap_stats_ptrtbl(zap_t *zap, uint64_t *tbl, int len, zap_stats_t *zs)  in zap_stats_ptrtbl()  argument
1416 		int err = zap_get_leaf_byblk(zap, tbl[i], NULL, RW_READER, &l);  in zap_stats_ptrtbl()
1418 			zap_leaf_stats(zap, l, zs);  in zap_stats_ptrtbl()
1425 fzap_get_stats(zap_t *zap, zap_stats_t *zs)  in fzap_get_stats()  argument
1427 	int bs = FZAP_BLOCK_SHIFT(zap);  in fzap_get_stats()
1433 	zs->zs_num_leafs = zap_f_phys(zap)->zap_num_leafs;  in fzap_get_stats()
1434 	zs->zs_num_entries = zap_f_phys(zap)->zap_num_entries;  in fzap_get_stats()
1435 	zs->zs_num_blocks = zap_f_phys(zap)->zap_freeblk;  in fzap_get_stats()
1436 	zs->zs_block_type = zap_f_phys(zap)->zap_block_type;  in fzap_get_stats()
1437 	zs->zs_magic = zap_f_phys(zap)->zap_magic;  in fzap_get_stats()
1438 	zs->zs_salt = zap_f_phys(zap)->zap_salt;  in fzap_get_stats()
1443 	zs->zs_ptrtbl_len = 1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift;  in fzap_get_stats()
1444 	zs->zs_ptrtbl_nextblk = zap_f_phys(zap)->zap_ptrtbl.zt_nextblk;  in fzap_get_stats()
1446 	    zap_f_phys(zap)->zap_ptrtbl.zt_blks_copied;  in fzap_get_stats()
1447 	zs->zs_ptrtbl_zt_blk = zap_f_phys(zap)->zap_ptrtbl.zt_blk;  in fzap_get_stats()
1448 	zs->zs_ptrtbl_zt_numblks = zap_f_phys(zap)->zap_ptrtbl.zt_numblks;  in fzap_get_stats()
1449 	zs->zs_ptrtbl_zt_shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;  in fzap_get_stats()
1451 	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {  in fzap_get_stats()
1453 		zap_stats_ptrtbl(zap, &ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),  in fzap_get_stats()
1454 		    1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap), zs);  in fzap_get_stats()
1456 		dmu_prefetch_by_dnode(zap->zap_dnode, 0,  in fzap_get_stats()
1457 		    zap_f_phys(zap)->zap_ptrtbl.zt_blk << bs,  in fzap_get_stats()
1458 		    zap_f_phys(zap)->zap_ptrtbl.zt_numblks << bs,  in fzap_get_stats()
1461 		for (int b = 0; b < zap_f_phys(zap)->zap_ptrtbl.zt_numblks;  in fzap_get_stats()
1466 			err = dmu_buf_hold_by_dnode(zap->zap_dnode,  in fzap_get_stats()
1467 			    (zap_f_phys(zap)->zap_ptrtbl.zt_blk + b) << bs,  in fzap_get_stats()
1470 				zap_stats_ptrtbl(zap, db->db_data,  in fzap_get_stats()
1482 zap_trunc(zap_t *zap)  in zap_trunc()  argument
1487 	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));  in zap_trunc()
1489 	if (zap_f_phys(zap)->zap_ptrtbl.zt_blk > 0) {  in zap_trunc()
1491 		nentries = (1 << zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in zap_trunc()
1492 		lastblk = zap_f_phys(zap)->zap_ptrtbl.zt_blk +  in zap_trunc()
1493 		    zap_f_phys(zap)->zap_ptrtbl.zt_numblks - 1;  in zap_trunc()
1496 		nentries = (1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap));  in zap_trunc()
1502 		if (zap_idx_to_blk(zap, idx, &blk) != 0)  in zap_trunc()
1508 	ASSERT3U(lastblk, <, zap_f_phys(zap)->zap_freeblk);  in zap_trunc()
1510 	zap_f_phys(zap)->zap_freeblk = lastblk + 1;  in zap_trunc()
1514  * ZAP shrinking algorithm.
1516  * We shrink ZAP recuresively removing empty leaves. We can remove an empty leaf
1541 	zap_t *zap = zn->zn_zap;  in zap_shrink()  local
1542 	int64_t zt_shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;  in zap_shrink()
1550 	ASSERT3U(prefix_len, <=, zap_f_phys(zap)->zap_ptrtbl.zt_shift);  in zap_shrink()
1551 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));  in zap_shrink()
1572 		if (check_sibling_ptrtbl_range(zap, sl_prefix, prefix_len) == 0)  in zap_shrink()
1586 		if ((err = zap_deref_leaf(zap, sl_hash, tx, RW_READER,  in zap_shrink()
1605 		 * we need to lock ZAP ptrtbl as WRITER.  in zap_shrink()
1607 		if (!writer && (writer = zap_tryupgradedir(zap, tx)) == 0) {  in zap_shrink()
1620 			rw_exit(&zap->zap_rwlock);  in zap_shrink()
1621 			rw_enter(&zap->zap_rwlock, RW_WRITER);  in zap_shrink()
1622 			dmu_buf_will_dirty(zap->zap_dbuf, tx);  in zap_shrink()
1624 			zt_shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;  in zap_shrink()
1636 			if ((err = zap_deref_leaf(zap, (slbit ? sl_hash : hash),  in zap_shrink()
1650 		if ((err = zap_deref_leaf(zap, (slbit ? hash : sl_hash), tx,  in zap_shrink()
1672 		if ((err = zap_set_idx_range_to_blk(zap, idx, nptrs, l->l_blkid,  in zap_shrink()
1681 		int bs = FZAP_BLOCK_SHIFT(zap);  in zap_shrink()
1682 		if (sl_blkid == zap_f_phys(zap)->zap_freeblk - 1)  in zap_shrink()
1685 		(void) dmu_free_range(zap->zap_objset, zap->zap_object,  in zap_shrink()
1689 		zap_f_phys(zap)->zap_num_leafs--;  in zap_shrink()
1702 		zap_trunc(zap);  in zap_shrink()
1711 	"When iterating ZAP object, prefetch it");
1714 	"Enable ZAP shrinking");