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, 2015 by Delphix. All rights reserved.
24 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
25 */
26
27/*
28 * This file contains the top half of the zfs directory structure
29 * implementation. The bottom half is in zap_leaf.c.
30 *
31 * The zdir is an extendable hash data structure. There is a table of
32 * pointers to buckets (zap_t->zd_data->zd_leafs). The buckets are
33 * each a constant size and hold a variable number of directory entries.
34 * The buckets (aka "leaf nodes") are implemented in zap_leaf.c.
35 *
36 * The pointer table holds a power of 2 number of pointers.
37 * (1<<zap_t->zd_data->zd_phys->zd_prefix_len).  The bucket pointed to
38 * by the pointer at index i in the table holds entries whose hash value
39 * has a zd_prefix_len - bit prefix
40 */
41
42#include <sys/spa.h>
43#include <sys/dmu.h>
44#include <sys/zfs_context.h>
45#include <sys/zfs_znode.h>
46#include <sys/fs/zfs.h>
47#include <sys/zap.h>
48#include <sys/refcount.h>
49#include <sys/zap_impl.h>
50#include <sys/zap_leaf.h>
51
52int fzap_default_block_shift = 14; /* 16k blocksize */
53
54extern inline zap_phys_t *zap_f_phys(zap_t *zap);
55
56static uint64_t zap_allocate_blocks(zap_t *zap, int nblocks);
57
58void
59fzap_byteswap(void *vbuf, size_t size)
60{
61	uint64_t block_type;
62
63	block_type = *(uint64_t *)vbuf;
64
65	if (block_type == ZBT_LEAF || block_type == BSWAP_64(ZBT_LEAF))
66		zap_leaf_byteswap(vbuf, size);
67	else {
68		/* it's a ptrtbl block */
69		byteswap_uint64_array(vbuf, size);
70	}
71}
72
73void
74fzap_upgrade(zap_t *zap, dmu_tx_t *tx, zap_flags_t flags)
75{
76	dmu_buf_t *db;
77	zap_leaf_t *l;
78	int i;
79	zap_phys_t *zp;
80
81	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
82	zap->zap_ismicro = FALSE;
83
84	zap->zap_dbu.dbu_evict_func = zap_evict;
85
86	mutex_init(&zap->zap_f.zap_num_entries_mtx, 0, 0, 0);
87	zap->zap_f.zap_block_shift = highbit64(zap->zap_dbuf->db_size) - 1;
88
89	zp = zap_f_phys(zap);
90	/*
91	 * explicitly zero it since it might be coming from an
92	 * initialized microzap
93	 */
94	bzero(zap->zap_dbuf->db_data, zap->zap_dbuf->db_size);
95	zp->zap_block_type = ZBT_HEADER;
96	zp->zap_magic = ZAP_MAGIC;
97
98	zp->zap_ptrtbl.zt_shift = ZAP_EMBEDDED_PTRTBL_SHIFT(zap);
99
100	zp->zap_freeblk = 2;		/* block 1 will be the first leaf */
101	zp->zap_num_leafs = 1;
102	zp->zap_num_entries = 0;
103	zp->zap_salt = zap->zap_salt;
104	zp->zap_normflags = zap->zap_normflags;
105	zp->zap_flags = flags;
106
107	/* block 1 will be the first leaf */
108	for (i = 0; i < (1<<zp->zap_ptrtbl.zt_shift); i++)
109		ZAP_EMBEDDED_PTRTBL_ENT(zap, i) = 1;
110
111	/*
112	 * set up block 1 - the first leaf
113	 */
114	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
115	    1<<FZAP_BLOCK_SHIFT(zap), FTAG, &db, DMU_READ_NO_PREFETCH));
116	dmu_buf_will_dirty(db, tx);
117
118	l = kmem_zalloc(sizeof (zap_leaf_t), KM_SLEEP);
119	l->l_dbuf = db;
120
121	zap_leaf_init(l, zp->zap_normflags != 0);
122
123	kmem_free(l, sizeof (zap_leaf_t));
124	dmu_buf_rele(db, FTAG);
125}
126
127static int
128zap_tryupgradedir(zap_t *zap, dmu_tx_t *tx)
129{
130	if (RW_WRITE_HELD(&zap->zap_rwlock))
131		return (1);
132	if (rw_tryupgrade(&zap->zap_rwlock)) {
133		dmu_buf_will_dirty(zap->zap_dbuf, tx);
134		return (1);
135	}
136	return (0);
137}
138
139/*
140 * Generic routines for dealing with the pointer & cookie tables.
141 */
142
143static int
144zap_table_grow(zap_t *zap, zap_table_phys_t *tbl,
145    void (*transfer_func)(const uint64_t *src, uint64_t *dst, int n),
146    dmu_tx_t *tx)
147{
148	uint64_t b, newblk;
149	dmu_buf_t *db_old, *db_new;
150	int err;
151	int bs = FZAP_BLOCK_SHIFT(zap);
152	int hepb = 1<<(bs-4);
153	/* hepb = half the number of entries in a block */
154
155	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
156	ASSERT(tbl->zt_blk != 0);
157	ASSERT(tbl->zt_numblks > 0);
158
159	if (tbl->zt_nextblk != 0) {
160		newblk = tbl->zt_nextblk;
161	} else {
162		newblk = zap_allocate_blocks(zap, tbl->zt_numblks * 2);
163		tbl->zt_nextblk = newblk;
164		ASSERT0(tbl->zt_blks_copied);
165		dmu_prefetch(zap->zap_objset, zap->zap_object, 0,
166		    tbl->zt_blk << bs, tbl->zt_numblks << bs,
167		    ZIO_PRIORITY_SYNC_READ);
168	}
169
170	/*
171	 * Copy the ptrtbl from the old to new location.
172	 */
173
174	b = tbl->zt_blks_copied;
175	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
176	    (tbl->zt_blk + b) << bs, FTAG, &db_old, DMU_READ_NO_PREFETCH);
177	if (err)
178		return (err);
179
180	/* first half of entries in old[b] go to new[2*b+0] */
181	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
182	    (newblk + 2*b+0) << bs, FTAG, &db_new, DMU_READ_NO_PREFETCH));
183	dmu_buf_will_dirty(db_new, tx);
184	transfer_func(db_old->db_data, db_new->db_data, hepb);
185	dmu_buf_rele(db_new, FTAG);
186
187	/* second half of entries in old[b] go to new[2*b+1] */
188	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
189	    (newblk + 2*b+1) << bs, FTAG, &db_new, DMU_READ_NO_PREFETCH));
190	dmu_buf_will_dirty(db_new, tx);
191	transfer_func((uint64_t *)db_old->db_data + hepb,
192	    db_new->db_data, hepb);
193	dmu_buf_rele(db_new, FTAG);
194
195	dmu_buf_rele(db_old, FTAG);
196
197	tbl->zt_blks_copied++;
198
199	dprintf("copied block %llu of %llu\n",
200	    tbl->zt_blks_copied, tbl->zt_numblks);
201
202	if (tbl->zt_blks_copied == tbl->zt_numblks) {
203		(void) dmu_free_range(zap->zap_objset, zap->zap_object,
204		    tbl->zt_blk << bs, tbl->zt_numblks << bs, tx);
205
206		tbl->zt_blk = newblk;
207		tbl->zt_numblks *= 2;
208		tbl->zt_shift++;
209		tbl->zt_nextblk = 0;
210		tbl->zt_blks_copied = 0;
211
212		dprintf("finished; numblocks now %llu (%lluk entries)\n",
213		    tbl->zt_numblks, 1<<(tbl->zt_shift-10));
214	}
215
216	return (0);
217}
218
219static int
220zap_table_store(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t val,
221    dmu_tx_t *tx)
222{
223	int err;
224	uint64_t blk, off;
225	int bs = FZAP_BLOCK_SHIFT(zap);
226	dmu_buf_t *db;
227
228	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
229	ASSERT(tbl->zt_blk != 0);
230
231	dprintf("storing %llx at index %llx\n", val, idx);
232
233	blk = idx >> (bs-3);
234	off = idx & ((1<<(bs-3))-1);
235
236	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
237	    (tbl->zt_blk + blk) << bs, FTAG, &db, DMU_READ_NO_PREFETCH);
238	if (err)
239		return (err);
240	dmu_buf_will_dirty(db, tx);
241
242	if (tbl->zt_nextblk != 0) {
243		uint64_t idx2 = idx * 2;
244		uint64_t blk2 = idx2 >> (bs-3);
245		uint64_t off2 = idx2 & ((1<<(bs-3))-1);
246		dmu_buf_t *db2;
247
248		err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
249		    (tbl->zt_nextblk + blk2) << bs, FTAG, &db2,
250		    DMU_READ_NO_PREFETCH);
251		if (err) {
252			dmu_buf_rele(db, FTAG);
253			return (err);
254		}
255		dmu_buf_will_dirty(db2, tx);
256		((uint64_t *)db2->db_data)[off2] = val;
257		((uint64_t *)db2->db_data)[off2+1] = val;
258		dmu_buf_rele(db2, FTAG);
259	}
260
261	((uint64_t *)db->db_data)[off] = val;
262	dmu_buf_rele(db, FTAG);
263
264	return (0);
265}
266
267static int
268zap_table_load(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t *valp)
269{
270	uint64_t blk, off;
271	int err;
272	dmu_buf_t *db;
273	int bs = FZAP_BLOCK_SHIFT(zap);
274
275	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
276
277	blk = idx >> (bs-3);
278	off = idx & ((1<<(bs-3))-1);
279
280	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
281	    (tbl->zt_blk + blk) << bs, FTAG, &db, DMU_READ_NO_PREFETCH);
282	if (err)
283		return (err);
284	*valp = ((uint64_t *)db->db_data)[off];
285	dmu_buf_rele(db, FTAG);
286
287	if (tbl->zt_nextblk != 0) {
288		/*
289		 * read the nextblk for the sake of i/o error checking,
290		 * so that zap_table_load() will catch errors for
291		 * zap_table_store.
292		 */
293		blk = (idx*2) >> (bs-3);
294
295		err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
296		    (tbl->zt_nextblk + blk) << bs, FTAG, &db,
297		    DMU_READ_NO_PREFETCH);
298		if (err == 0)
299			dmu_buf_rele(db, FTAG);
300	}
301	return (err);
302}
303
304/*
305 * Routines for growing the ptrtbl.
306 */
307
308static void
309zap_ptrtbl_transfer(const uint64_t *src, uint64_t *dst, int n)
310{
311	int i;
312	for (i = 0; i < n; i++) {
313		uint64_t lb = src[i];
314		dst[2*i+0] = lb;
315		dst[2*i+1] = lb;
316	}
317}
318
319static int
320zap_grow_ptrtbl(zap_t *zap, dmu_tx_t *tx)
321{
322	/*
323	 * The pointer table should never use more hash bits than we
324	 * have (otherwise we'd be using useless zero bits to index it).
325	 * If we are within 2 bits of running out, stop growing, since
326	 * this is already an aberrant condition.
327	 */
328	if (zap_f_phys(zap)->zap_ptrtbl.zt_shift >= zap_hashbits(zap) - 2)
329		return (SET_ERROR(ENOSPC));
330
331	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {
332		/*
333		 * We are outgrowing the "embedded" ptrtbl (the one
334		 * stored in the header block).  Give it its own entire
335		 * block, which will double the size of the ptrtbl.
336		 */
337		uint64_t newblk;
338		dmu_buf_t *db_new;
339		int err;
340
341		ASSERT3U(zap_f_phys(zap)->zap_ptrtbl.zt_shift, ==,
342		    ZAP_EMBEDDED_PTRTBL_SHIFT(zap));
343		ASSERT0(zap_f_phys(zap)->zap_ptrtbl.zt_blk);
344
345		newblk = zap_allocate_blocks(zap, 1);
346		err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
347		    newblk << FZAP_BLOCK_SHIFT(zap), FTAG, &db_new,
348		    DMU_READ_NO_PREFETCH);
349		if (err)
350			return (err);
351		dmu_buf_will_dirty(db_new, tx);
352		zap_ptrtbl_transfer(&ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
353		    db_new->db_data, 1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap));
354		dmu_buf_rele(db_new, FTAG);
355
356		zap_f_phys(zap)->zap_ptrtbl.zt_blk = newblk;
357		zap_f_phys(zap)->zap_ptrtbl.zt_numblks = 1;
358		zap_f_phys(zap)->zap_ptrtbl.zt_shift++;
359
360		ASSERT3U(1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift, ==,
361		    zap_f_phys(zap)->zap_ptrtbl.zt_numblks <<
362		    (FZAP_BLOCK_SHIFT(zap)-3));
363
364		return (0);
365	} else {
366		return (zap_table_grow(zap, &zap_f_phys(zap)->zap_ptrtbl,
367		    zap_ptrtbl_transfer, tx));
368	}
369}
370
371static void
372zap_increment_num_entries(zap_t *zap, int delta, dmu_tx_t *tx)
373{
374	dmu_buf_will_dirty(zap->zap_dbuf, tx);
375	mutex_enter(&zap->zap_f.zap_num_entries_mtx);
376	ASSERT(delta > 0 || zap_f_phys(zap)->zap_num_entries >= -delta);
377	zap_f_phys(zap)->zap_num_entries += delta;
378	mutex_exit(&zap->zap_f.zap_num_entries_mtx);
379}
380
381static uint64_t
382zap_allocate_blocks(zap_t *zap, int nblocks)
383{
384	uint64_t newblk;
385	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
386	newblk = zap_f_phys(zap)->zap_freeblk;
387	zap_f_phys(zap)->zap_freeblk += nblocks;
388	return (newblk);
389}
390
391static void
392zap_leaf_pageout(void *dbu)
393{
394	zap_leaf_t *l = dbu;
395
396	rw_destroy(&l->l_rwlock);
397	kmem_free(l, sizeof (zap_leaf_t));
398}
399
400static zap_leaf_t *
401zap_create_leaf(zap_t *zap, dmu_tx_t *tx)
402{
403	void *winner;
404	zap_leaf_t *l = kmem_zalloc(sizeof (zap_leaf_t), KM_SLEEP);
405
406	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
407
408	rw_init(&l->l_rwlock, 0, 0, 0);
409	rw_enter(&l->l_rwlock, RW_WRITER);
410	l->l_blkid = zap_allocate_blocks(zap, 1);
411	l->l_dbuf = NULL;
412
413	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
414	    l->l_blkid << FZAP_BLOCK_SHIFT(zap), NULL, &l->l_dbuf,
415	    DMU_READ_NO_PREFETCH));
416	dmu_buf_init_user(&l->l_dbu, zap_leaf_pageout, &l->l_dbuf);
417	winner = dmu_buf_set_user(l->l_dbuf, &l->l_dbu);
418	ASSERT(winner == NULL);
419	dmu_buf_will_dirty(l->l_dbuf, tx);
420
421	zap_leaf_init(l, zap->zap_normflags != 0);
422
423	zap_f_phys(zap)->zap_num_leafs++;
424
425	return (l);
426}
427
428int
429fzap_count(zap_t *zap, uint64_t *count)
430{
431	ASSERT(!zap->zap_ismicro);
432	mutex_enter(&zap->zap_f.zap_num_entries_mtx); /* unnecessary */
433	*count = zap_f_phys(zap)->zap_num_entries;
434	mutex_exit(&zap->zap_f.zap_num_entries_mtx);
435	return (0);
436}
437
438/*
439 * Routines for obtaining zap_leaf_t's
440 */
441
442void
443zap_put_leaf(zap_leaf_t *l)
444{
445	rw_exit(&l->l_rwlock);
446	dmu_buf_rele(l->l_dbuf, NULL);
447}
448
449static zap_leaf_t *
450zap_open_leaf(uint64_t blkid, dmu_buf_t *db)
451{
452	zap_leaf_t *l, *winner;
453
454	ASSERT(blkid != 0);
455
456	l = kmem_zalloc(sizeof (zap_leaf_t), KM_SLEEP);
457	rw_init(&l->l_rwlock, 0, 0, 0);
458	rw_enter(&l->l_rwlock, RW_WRITER);
459	l->l_blkid = blkid;
460	l->l_bs = highbit64(db->db_size) - 1;
461	l->l_dbuf = db;
462
463	dmu_buf_init_user(&l->l_dbu, zap_leaf_pageout, &l->l_dbuf);
464	winner = dmu_buf_set_user(db, &l->l_dbu);
465
466	rw_exit(&l->l_rwlock);
467	if (winner != NULL) {
468		/* someone else set it first */
469		zap_leaf_pageout(&l->l_dbu);
470		l = winner;
471	}
472
473	/*
474	 * lhr_pad was previously used for the next leaf in the leaf
475	 * chain.  There should be no chained leafs (as we have removed
476	 * support for them).
477	 */
478	ASSERT0(zap_leaf_phys(l)->l_hdr.lh_pad1);
479
480	/*
481	 * There should be more hash entries than there can be
482	 * chunks to put in the hash table
483	 */
484	ASSERT3U(ZAP_LEAF_HASH_NUMENTRIES(l), >, ZAP_LEAF_NUMCHUNKS(l) / 3);
485
486	/* The chunks should begin at the end of the hash table */
487	ASSERT3P(&ZAP_LEAF_CHUNK(l, 0), ==,
488	    &zap_leaf_phys(l)->l_hash[ZAP_LEAF_HASH_NUMENTRIES(l)]);
489
490	/* The chunks should end at the end of the block */
491	ASSERT3U((uintptr_t)&ZAP_LEAF_CHUNK(l, ZAP_LEAF_NUMCHUNKS(l)) -
492	    (uintptr_t)zap_leaf_phys(l), ==, l->l_dbuf->db_size);
493
494	return (l);
495}
496
497static int
498zap_get_leaf_byblk(zap_t *zap, uint64_t blkid, dmu_tx_t *tx, krw_t lt,
499    zap_leaf_t **lp)
500{
501	dmu_buf_t *db;
502	zap_leaf_t *l;
503	int bs = FZAP_BLOCK_SHIFT(zap);
504	int err;
505
506	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
507
508	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
509	    blkid << bs, NULL, &db, DMU_READ_NO_PREFETCH);
510	if (err)
511		return (err);
512
513	ASSERT3U(db->db_object, ==, zap->zap_object);
514	ASSERT3U(db->db_offset, ==, blkid << bs);
515	ASSERT3U(db->db_size, ==, 1 << bs);
516	ASSERT(blkid != 0);
517
518	l = dmu_buf_get_user(db);
519
520	if (l == NULL)
521		l = zap_open_leaf(blkid, db);
522
523	rw_enter(&l->l_rwlock, lt);
524	/*
525	 * Must lock before dirtying, otherwise zap_leaf_phys(l) could change,
526	 * causing ASSERT below to fail.
527	 */
528	if (lt == RW_WRITER)
529		dmu_buf_will_dirty(db, tx);
530	ASSERT3U(l->l_blkid, ==, blkid);
531	ASSERT3P(l->l_dbuf, ==, db);
532	ASSERT3U(zap_leaf_phys(l)->l_hdr.lh_block_type, ==, ZBT_LEAF);
533	ASSERT3U(zap_leaf_phys(l)->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);
534
535	*lp = l;
536	return (0);
537}
538
539static int
540zap_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t *valp)
541{
542	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
543
544	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {
545		ASSERT3U(idx, <,
546		    (1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift));
547		*valp = ZAP_EMBEDDED_PTRTBL_ENT(zap, idx);
548		return (0);
549	} else {
550		return (zap_table_load(zap, &zap_f_phys(zap)->zap_ptrtbl,
551		    idx, valp));
552	}
553}
554
555static int
556zap_set_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t blk, dmu_tx_t *tx)
557{
558	ASSERT(tx != NULL);
559	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
560
561	if (zap_f_phys(zap)->zap_ptrtbl.zt_blk == 0) {
562		ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) = blk;
563		return (0);
564	} else {
565		return (zap_table_store(zap, &zap_f_phys(zap)->zap_ptrtbl,
566		    idx, blk, tx));
567	}
568}
569
570static int
571zap_deref_leaf(zap_t *zap, uint64_t h, dmu_tx_t *tx, krw_t lt, zap_leaf_t **lp)
572{
573	uint64_t idx, blk;
574	int err;
575
576	ASSERT(zap->zap_dbuf == NULL ||
577	    zap_f_phys(zap) == zap->zap_dbuf->db_data);
578
579	/* Reality check for corrupt zap objects (leaf or header). */
580	if ((zap_f_phys(zap)->zap_block_type != ZBT_LEAF &&
581	    zap_f_phys(zap)->zap_block_type != ZBT_HEADER) ||
582	    zap_f_phys(zap)->zap_magic != ZAP_MAGIC) {
583		return (SET_ERROR(EIO));
584	}
585
586	idx = ZAP_HASH_IDX(h, zap_f_phys(zap)->zap_ptrtbl.zt_shift);
587	err = zap_idx_to_blk(zap, idx, &blk);
588	if (err != 0)
589		return (err);
590	err = zap_get_leaf_byblk(zap, blk, tx, lt, lp);
591
592	ASSERT(err ||
593	    ZAP_HASH_IDX(h, zap_leaf_phys(*lp)->l_hdr.lh_prefix_len) ==
594	    zap_leaf_phys(*lp)->l_hdr.lh_prefix);
595	return (err);
596}
597
598static int
599zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx, zap_leaf_t **lp)
600{
601	zap_t *zap = zn->zn_zap;
602	uint64_t hash = zn->zn_hash;
603	zap_leaf_t *nl;
604	int prefix_diff, i, err;
605	uint64_t sibling;
606	int old_prefix_len = zap_leaf_phys(l)->l_hdr.lh_prefix_len;
607
608	ASSERT3U(old_prefix_len, <=, zap_f_phys(zap)->zap_ptrtbl.zt_shift);
609	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
610
611	ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
612	    zap_leaf_phys(l)->l_hdr.lh_prefix);
613
614	if (zap_tryupgradedir(zap, tx) == 0 ||
615	    old_prefix_len == zap_f_phys(zap)->zap_ptrtbl.zt_shift) {
616		/* We failed to upgrade, or need to grow the pointer table */
617		objset_t *os = zap->zap_objset;
618		uint64_t object = zap->zap_object;
619
620		zap_put_leaf(l);
621		zap_unlockdir(zap);
622		err = zap_lockdir(os, object, tx, RW_WRITER,
623		    FALSE, FALSE, &zn->zn_zap);
624		zap = zn->zn_zap;
625		if (err)
626			return (err);
627		ASSERT(!zap->zap_ismicro);
628
629		while (old_prefix_len ==
630		    zap_f_phys(zap)->zap_ptrtbl.zt_shift) {
631			err = zap_grow_ptrtbl(zap, tx);
632			if (err)
633				return (err);
634		}
635
636		err = zap_deref_leaf(zap, hash, tx, RW_WRITER, &l);
637		if (err)
638			return (err);
639
640		if (zap_leaf_phys(l)->l_hdr.lh_prefix_len != old_prefix_len) {
641			/* it split while our locks were down */
642			*lp = l;
643			return (0);
644		}
645	}
646	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
647	ASSERT3U(old_prefix_len, <, zap_f_phys(zap)->zap_ptrtbl.zt_shift);
648	ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
649	    zap_leaf_phys(l)->l_hdr.lh_prefix);
650
651	prefix_diff = zap_f_phys(zap)->zap_ptrtbl.zt_shift -
652	    (old_prefix_len + 1);
653	sibling = (ZAP_HASH_IDX(hash, old_prefix_len + 1) | 1) << prefix_diff;
654
655	/* check for i/o errors before doing zap_leaf_split */
656	for (i = 0; i < (1ULL<<prefix_diff); i++) {
657		uint64_t blk;
658		err = zap_idx_to_blk(zap, sibling+i, &blk);
659		if (err)
660			return (err);
661		ASSERT3U(blk, ==, l->l_blkid);
662	}
663
664	nl = zap_create_leaf(zap, tx);
665	zap_leaf_split(l, nl, zap->zap_normflags != 0);
666
667	/* set sibling pointers */
668	for (i = 0; i < (1ULL << prefix_diff); i++) {
669		err = zap_set_idx_to_blk(zap, sibling+i, nl->l_blkid, tx);
670		ASSERT0(err); /* we checked for i/o errors above */
671	}
672
673	if (hash & (1ULL << (64 - zap_leaf_phys(l)->l_hdr.lh_prefix_len))) {
674		/* we want the sibling */
675		zap_put_leaf(l);
676		*lp = nl;
677	} else {
678		zap_put_leaf(nl);
679		*lp = l;
680	}
681
682	return (0);
683}
684
685static void
686zap_put_leaf_maybe_grow_ptrtbl(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx)
687{
688	zap_t *zap = zn->zn_zap;
689	int shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;
690	int leaffull = (zap_leaf_phys(l)->l_hdr.lh_prefix_len == shift &&
691	    zap_leaf_phys(l)->l_hdr.lh_nfree < ZAP_LEAF_LOW_WATER);
692
693	zap_put_leaf(l);
694
695	if (leaffull || zap_f_phys(zap)->zap_ptrtbl.zt_nextblk) {
696		int err;
697
698		/*
699		 * We are in the middle of growing the pointer table, or
700		 * this leaf will soon make us grow it.
701		 */
702		if (zap_tryupgradedir(zap, tx) == 0) {
703			objset_t *os = zap->zap_objset;
704			uint64_t zapobj = zap->zap_object;
705
706			zap_unlockdir(zap);
707			err = zap_lockdir(os, zapobj, tx,
708			    RW_WRITER, FALSE, FALSE, &zn->zn_zap);
709			zap = zn->zn_zap;
710			if (err)
711				return;
712		}
713
714		/* could have finished growing while our locks were down */
715		if (zap_f_phys(zap)->zap_ptrtbl.zt_shift == shift)
716			(void) zap_grow_ptrtbl(zap, tx);
717	}
718}
719
720static int
721fzap_checkname(zap_name_t *zn)
722{
723	if (zn->zn_key_orig_numints * zn->zn_key_intlen > ZAP_MAXNAMELEN)
724		return (SET_ERROR(ENAMETOOLONG));
725	return (0);
726}
727
728static int
729fzap_checksize(uint64_t integer_size, uint64_t num_integers)
730{
731	/* Only integer sizes supported by C */
732	switch (integer_size) {
733	case 1:
734	case 2:
735	case 4:
736	case 8:
737		break;
738	default:
739		return (SET_ERROR(EINVAL));
740	}
741
742	if (integer_size * num_integers > ZAP_MAXVALUELEN)
743		return (E2BIG);
744
745	return (0);
746}
747
748static int
749fzap_check(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers)
750{
751	int err;
752
753	if ((err = fzap_checkname(zn)) != 0)
754		return (err);
755	return (fzap_checksize(integer_size, num_integers));
756}
757
758/*
759 * Routines for manipulating attributes.
760 */
761int
762fzap_lookup(zap_name_t *zn,
763    uint64_t integer_size, uint64_t num_integers, void *buf,
764    char *realname, int rn_len, boolean_t *ncp)
765{
766	zap_leaf_t *l;
767	int err;
768	zap_entry_handle_t zeh;
769
770	if ((err = fzap_checkname(zn)) != 0)
771		return (err);
772
773	err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, NULL, RW_READER, &l);
774	if (err != 0)
775		return (err);
776	err = zap_leaf_lookup(l, zn, &zeh);
777	if (err == 0) {
778		if ((err = fzap_checksize(integer_size, num_integers)) != 0) {
779			zap_put_leaf(l);
780			return (err);
781		}
782
783		err = zap_entry_read(&zeh, integer_size, num_integers, buf);
784		(void) zap_entry_read_name(zn->zn_zap, &zeh, rn_len, realname);
785		if (ncp) {
786			*ncp = zap_entry_normalization_conflict(&zeh,
787			    zn, NULL, zn->zn_zap);
788		}
789	}
790
791	zap_put_leaf(l);
792	return (err);
793}
794
795int
796fzap_add_cd(zap_name_t *zn,
797    uint64_t integer_size, uint64_t num_integers,
798    const void *val, uint32_t cd, dmu_tx_t *tx)
799{
800	zap_leaf_t *l;
801	int err;
802	zap_entry_handle_t zeh;
803	zap_t *zap = zn->zn_zap;
804
805	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
806	ASSERT(!zap->zap_ismicro);
807	ASSERT(fzap_check(zn, integer_size, num_integers) == 0);
808
809	err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);
810	if (err != 0)
811		return (err);
812retry:
813	err = zap_leaf_lookup(l, zn, &zeh);
814	if (err == 0) {
815		err = SET_ERROR(EEXIST);
816		goto out;
817	}
818	if (err != ENOENT)
819		goto out;
820
821	err = zap_entry_create(l, zn, cd,
822	    integer_size, num_integers, val, &zeh);
823
824	if (err == 0) {
825		zap_increment_num_entries(zap, 1, tx);
826	} else if (err == EAGAIN) {
827		err = zap_expand_leaf(zn, l, tx, &l);
828		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */
829		if (err == 0)
830			goto retry;
831	}
832
833out:
834	if (zap != NULL)
835		zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
836	return (err);
837}
838
839int
840fzap_add(zap_name_t *zn,
841    uint64_t integer_size, uint64_t num_integers,
842    const void *val, dmu_tx_t *tx)
843{
844	int err = fzap_check(zn, integer_size, num_integers);
845	if (err != 0)
846		return (err);
847
848	return (fzap_add_cd(zn, integer_size, num_integers,
849	    val, ZAP_NEED_CD, tx));
850}
851
852int
853fzap_update(zap_name_t *zn,
854    int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx)
855{
856	zap_leaf_t *l;
857	int err, create;
858	zap_entry_handle_t zeh;
859	zap_t *zap = zn->zn_zap;
860
861	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
862	err = fzap_check(zn, integer_size, num_integers);
863	if (err != 0)
864		return (err);
865
866	err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);
867	if (err != 0)
868		return (err);
869retry:
870	err = zap_leaf_lookup(l, zn, &zeh);
871	create = (err == ENOENT);
872	ASSERT(err == 0 || err == ENOENT);
873
874	if (create) {
875		err = zap_entry_create(l, zn, ZAP_NEED_CD,
876		    integer_size, num_integers, val, &zeh);
877		if (err == 0)
878			zap_increment_num_entries(zap, 1, tx);
879	} else {
880		err = zap_entry_update(&zeh, integer_size, num_integers, val);
881	}
882
883	if (err == EAGAIN) {
884		err = zap_expand_leaf(zn, l, tx, &l);
885		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */
886		if (err == 0)
887			goto retry;
888	}
889
890	if (zap != NULL)
891		zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
892	return (err);
893}
894
895int
896fzap_length(zap_name_t *zn,
897    uint64_t *integer_size, uint64_t *num_integers)
898{
899	zap_leaf_t *l;
900	int err;
901	zap_entry_handle_t zeh;
902
903	err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, NULL, RW_READER, &l);
904	if (err != 0)
905		return (err);
906	err = zap_leaf_lookup(l, zn, &zeh);
907	if (err != 0)
908		goto out;
909
910	if (integer_size)
911		*integer_size = zeh.zeh_integer_size;
912	if (num_integers)
913		*num_integers = zeh.zeh_num_integers;
914out:
915	zap_put_leaf(l);
916	return (err);
917}
918
919int
920fzap_remove(zap_name_t *zn, dmu_tx_t *tx)
921{
922	zap_leaf_t *l;
923	int err;
924	zap_entry_handle_t zeh;
925
926	err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, tx, RW_WRITER, &l);
927	if (err != 0)
928		return (err);
929	err = zap_leaf_lookup(l, zn, &zeh);
930	if (err == 0) {
931		zap_entry_remove(&zeh);
932		zap_increment_num_entries(zn->zn_zap, -1, tx);
933	}
934	zap_put_leaf(l);
935	return (err);
936}
937
938void
939fzap_prefetch(zap_name_t *zn)
940{
941	uint64_t idx, blk;
942	zap_t *zap = zn->zn_zap;
943	int bs;
944
945	idx = ZAP_HASH_IDX(zn->zn_hash,
946	    zap_f_phys(zap)->zap_ptrtbl.zt_shift);
947	if (zap_idx_to_blk(zap, idx, &blk) != 0)
948		return;
949	bs = FZAP_BLOCK_SHIFT(zap);
950	dmu_prefetch(zap->zap_objset, zap->zap_object, 0, blk << bs, 1 << bs,
951	    ZIO_PRIORITY_SYNC_READ);
952}
953
954/*
955 * Helper functions for consumers.
956 */
957
958uint64_t
959zap_create_link(objset_t *os, dmu_object_type_t ot, uint64_t parent_obj,
960    const char *name, dmu_tx_t *tx)
961{
962	uint64_t new_obj;
963
964	VERIFY((new_obj = zap_create(os, ot, DMU_OT_NONE, 0, tx)) > 0);
965	VERIFY0(zap_add(os, parent_obj, name, sizeof (uint64_t), 1, &new_obj,
966	    tx));
967
968	return (new_obj);
969}
970
971int
972zap_value_search(objset_t *os, uint64_t zapobj, uint64_t value, uint64_t mask,
973    char *name)
974{
975	zap_cursor_t zc;
976	zap_attribute_t *za;
977	int err;
978
979	if (mask == 0)
980		mask = -1ULL;
981
982	za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
983	for (zap_cursor_init(&zc, os, zapobj);
984	    (err = zap_cursor_retrieve(&zc, za)) == 0;
985	    zap_cursor_advance(&zc)) {
986		if ((za->za_first_integer & mask) == (value & mask)) {
987			(void) strcpy(name, za->za_name);
988			break;
989		}
990	}
991	zap_cursor_fini(&zc);
992	kmem_free(za, sizeof (zap_attribute_t));
993	return (err);
994}
995
996int
997zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx)
998{
999	zap_cursor_t zc;
1000	zap_attribute_t za;
1001	int err;
1002
1003	err = 0;
1004	for (zap_cursor_init(&zc, os, fromobj);
1005	    zap_cursor_retrieve(&zc, &za) == 0;
1006	    (void) zap_cursor_advance(&zc)) {
1007		if (za.za_integer_length != 8 || za.za_num_integers != 1) {
1008			err = SET_ERROR(EINVAL);
1009			break;
1010		}
1011		err = zap_add(os, intoobj, za.za_name,
1012		    8, 1, &za.za_first_integer, tx);
1013		if (err)
1014			break;
1015	}
1016	zap_cursor_fini(&zc);
1017	return (err);
1018}
1019
1020int
1021zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
1022    uint64_t value, dmu_tx_t *tx)
1023{
1024	zap_cursor_t zc;
1025	zap_attribute_t za;
1026	int err;
1027
1028	err = 0;
1029	for (zap_cursor_init(&zc, os, fromobj);
1030	    zap_cursor_retrieve(&zc, &za) == 0;
1031	    (void) zap_cursor_advance(&zc)) {
1032		if (za.za_integer_length != 8 || za.za_num_integers != 1) {
1033			err = SET_ERROR(EINVAL);
1034			break;
1035		}
1036		err = zap_add(os, intoobj, za.za_name,
1037		    8, 1, &value, tx);
1038		if (err)
1039			break;
1040	}
1041	zap_cursor_fini(&zc);
1042	return (err);
1043}
1044
1045int
1046zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
1047    dmu_tx_t *tx)
1048{
1049	zap_cursor_t zc;
1050	zap_attribute_t za;
1051	int err;
1052
1053	err = 0;
1054	for (zap_cursor_init(&zc, os, fromobj);
1055	    zap_cursor_retrieve(&zc, &za) == 0;
1056	    (void) zap_cursor_advance(&zc)) {
1057		uint64_t delta = 0;
1058
1059		if (za.za_integer_length != 8 || za.za_num_integers != 1) {
1060			err = SET_ERROR(EINVAL);
1061			break;
1062		}
1063
1064		err = zap_lookup(os, intoobj, za.za_name, 8, 1, &delta);
1065		if (err != 0 && err != ENOENT)
1066			break;
1067		delta += za.za_first_integer;
1068		err = zap_update(os, intoobj, za.za_name, 8, 1, &delta, tx);
1069		if (err)
1070			break;
1071	}
1072	zap_cursor_fini(&zc);
1073	return (err);
1074}
1075
1076int
1077zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx)
1078{
1079	char name[20];
1080
1081	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
1082	return (zap_add(os, obj, name, 8, 1, &value, tx));
1083}
1084
1085int
1086zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx)
1087{
1088	char name[20];
1089
1090	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
1091	return (zap_remove(os, obj, name, tx));
1092}
1093
1094int
1095zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value)
1096{
1097	char name[20];
1098
1099	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
1100	return (zap_lookup(os, obj, name, 8, 1, &value));
1101}
1102
1103int
1104zap_add_int_key(objset_t *os, uint64_t obj,
1105    uint64_t key, uint64_t value, dmu_tx_t *tx)
1106{
1107	char name[20];
1108
1109	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
1110	return (zap_add(os, obj, name, 8, 1, &value, tx));
1111}
1112
1113int
1114zap_update_int_key(objset_t *os, uint64_t obj,
1115    uint64_t key, uint64_t value, dmu_tx_t *tx)
1116{
1117	char name[20];
1118
1119	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
1120	return (zap_update(os, obj, name, 8, 1, &value, tx));
1121}
1122
1123int
1124zap_lookup_int_key(objset_t *os, uint64_t obj, uint64_t key, uint64_t *valuep)
1125{
1126	char name[20];
1127
1128	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
1129	return (zap_lookup(os, obj, name, 8, 1, valuep));
1130}
1131
1132int
1133zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,
1134    dmu_tx_t *tx)
1135{
1136	uint64_t value = 0;
1137	int err;
1138
1139	if (delta == 0)
1140		return (0);
1141
1142	err = zap_lookup(os, obj, name, 8, 1, &value);
1143	if (err != 0 && err != ENOENT)
1144		return (err);
1145	value += delta;
1146	if (value == 0)
1147		err = zap_remove(os, obj, name, tx);
1148	else
1149		err = zap_update(os, obj, name, 8, 1, &value, tx);
1150	return (err);
1151}
1152
1153int
1154zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
1155    dmu_tx_t *tx)
1156{
1157	char name[20];
1158
1159	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
1160	return (zap_increment(os, obj, name, delta, tx));
1161}
1162
1163/*
1164 * Routines for iterating over the attributes.
1165 */
1166
1167int
1168fzap_cursor_retrieve(zap_t *zap, zap_cursor_t *zc, zap_attribute_t *za)
1169{
1170	int err = ENOENT;
1171	zap_entry_handle_t zeh;
1172	zap_leaf_t *l;
1173
1174	/* retrieve the next entry at or after zc_hash/zc_cd */
1175	/* if no entry, return ENOENT */
1176
1177	if (zc->zc_leaf &&
1178	    (ZAP_HASH_IDX(zc->zc_hash,
1179	    zap_leaf_phys(zc->zc_leaf)->l_hdr.lh_prefix_len) !=
1180	    zap_leaf_phys(zc->zc_leaf)->l_hdr.lh_prefix)) {
1181		rw_enter(&zc->zc_leaf->l_rwlock, RW_READER);
1182		zap_put_leaf(zc->zc_leaf);
1183		zc->zc_leaf = NULL;
1184	}
1185
1186again:
1187	if (zc->zc_leaf == NULL) {
1188		err = zap_deref_leaf(zap, zc->zc_hash, NULL, RW_READER,
1189		    &zc->zc_leaf);
1190		if (err != 0)
1191			return (err);
1192	} else {
1193		rw_enter(&zc->zc_leaf->l_rwlock, RW_READER);
1194	}
1195	l = zc->zc_leaf;
1196
1197	err = zap_leaf_lookup_closest(l, zc->zc_hash, zc->zc_cd, &zeh);
1198
1199	if (err == ENOENT) {
1200		uint64_t nocare =
1201		    (1ULL << (64 - zap_leaf_phys(l)->l_hdr.lh_prefix_len)) - 1;
1202		zc->zc_hash = (zc->zc_hash & ~nocare) + nocare + 1;
1203		zc->zc_cd = 0;
1204		if (zap_leaf_phys(l)->l_hdr.lh_prefix_len == 0 ||
1205		    zc->zc_hash == 0) {
1206			zc->zc_hash = -1ULL;
1207		} else {
1208			zap_put_leaf(zc->zc_leaf);
1209			zc->zc_leaf = NULL;
1210			goto again;
1211		}
1212	}
1213
1214	if (err == 0) {
1215		zc->zc_hash = zeh.zeh_hash;
1216		zc->zc_cd = zeh.zeh_cd;
1217		za->za_integer_length = zeh.zeh_integer_size;
1218		za->za_num_integers = zeh.zeh_num_integers;
1219		if (zeh.zeh_num_integers == 0) {
1220			za->za_first_integer = 0;
1221		} else {
1222			err = zap_entry_read(&zeh, 8, 1, &za->za_first_integer);
1223			ASSERT(err == 0 || err == EOVERFLOW);
1224		}
1225		err = zap_entry_read_name(zap, &zeh,
1226		    sizeof (za->za_name), za->za_name);
1227		ASSERT(err == 0);
1228
1229		za->za_normalization_conflict =
1230		    zap_entry_normalization_conflict(&zeh,
1231		    NULL, za->za_name, zap);
1232	}
1233	rw_exit(&zc->zc_leaf->l_rwlock);
1234	return (err);
1235}
1236
1237static void
1238zap_stats_ptrtbl(zap_t *zap, uint64_t *tbl, int len, zap_stats_t *zs)
1239{
1240	int i, err;
1241	uint64_t lastblk = 0;
1242
1243	/*
1244	 * NB: if a leaf has more pointers than an entire ptrtbl block
1245	 * can hold, then it'll be accounted for more than once, since
1246	 * we won't have lastblk.
1247	 */
1248	for (i = 0; i < len; i++) {
1249		zap_leaf_t *l;
1250
1251		if (tbl[i] == lastblk)
1252			continue;
1253		lastblk = tbl[i];
1254
1255		err = zap_get_leaf_byblk(zap, tbl[i], NULL, RW_READER, &l);
1256		if (err == 0) {
1257			zap_leaf_stats(zap, l, zs);
1258			zap_put_leaf(l);
1259		}
1260	}
1261}
1262
1263int
1264fzap_cursor_move_to_key(zap_cursor_t *zc, zap_name_t *zn)
1265{
1266	int err;
1267	zap_leaf_t *l;
1268	zap_entry_handle_t zeh;
1269
1270	if (zn->zn_key_orig_numints * zn->zn_key_intlen > ZAP_MAXNAMELEN)
1271		return (SET_ERROR(ENAMETOOLONG));
1272
1273	err = zap_deref_leaf(zc->zc_zap, zn->zn_hash, NULL, RW_READER, &l);
1274	if (err != 0)
1275		return (err);
1276
1277	err = zap_leaf_lookup(l, zn, &zeh);
1278	if (err != 0)
1279		return (err);
1280
1281	zc->zc_leaf = l;
1282	zc->zc_hash = zeh.zeh_hash;
1283	zc->zc_cd = zeh.zeh_cd;
1284
1285	return (err);
1286}
1287
1288void
1289fzap_get_stats(zap_t *zap, zap_stats_t *zs)
1290{
1291	int bs = FZAP_BLOCK_SHIFT(zap);
1292	zs->zs_blocksize = 1ULL << bs;
1293
1294	/*
1295	 * Set zap_phys_t fields
1296	 */
1297	zs->zs_num_leafs = zap_f_phys(zap)->zap_num_leafs;
1298	zs->zs_num_entries = zap_f_phys(zap)->zap_num_entries;
1299	zs->zs_num_blocks = zap_f_phys(zap)->zap_freeblk;
1300	zs->zs_block_type = zap_f_phys(zap)->zap_block_type;
1301	zs->zs_magic = zap_f_phys(zap)->zap_magic;
1302	zs->zs_salt = zap_f_phys(zap)->zap_salt;
1303
1304	/*
1305	 * Set zap_ptrtbl fields
1306	 */
1307	zs->zs_ptrtbl_len = 1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift;
1308	zs->zs_ptrtbl_nextblk = zap_f_phys(zap)->zap_ptrtbl.zt_nextblk;
1309	zs->zs_ptrtbl_blks_copied =
1310	    zap_f_phys(zap)->zap_ptrtbl.zt_blks_copied;
1311	zs->zs_ptrtbl_zt_blk = zap_f_phys(zap)->zap_ptrtbl.zt_blk;
1312	zs->zs_ptrtbl_zt_numblks = zap_f_phys(zap)->zap_ptrtbl.zt_numblks;
1313	zs->zs_ptrtbl_zt_shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;
1314
1315	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {
1316		/* the ptrtbl is entirely in the header block. */
1317		zap_stats_ptrtbl(zap, &ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
1318		    1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap), zs);
1319	} else {
1320		int b;
1321
1322		dmu_prefetch(zap->zap_objset, zap->zap_object, 0,
1323		    zap_f_phys(zap)->zap_ptrtbl.zt_blk << bs,
1324		    zap_f_phys(zap)->zap_ptrtbl.zt_numblks << bs,
1325		    ZIO_PRIORITY_SYNC_READ);
1326
1327		for (b = 0; b < zap_f_phys(zap)->zap_ptrtbl.zt_numblks;
1328		    b++) {
1329			dmu_buf_t *db;
1330			int err;
1331
1332			err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
1333			    (zap_f_phys(zap)->zap_ptrtbl.zt_blk + b) << bs,
1334			    FTAG, &db, DMU_READ_NO_PREFETCH);
1335			if (err == 0) {
1336				zap_stats_ptrtbl(zap, db->db_data,
1337				    1<<(bs-3), zs);
1338				dmu_buf_rele(db, FTAG);
1339			}
1340		}
1341	}
1342}
1343
1344int
1345fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
1346    uint64_t *tooverwrite)
1347{
1348	zap_t *zap = zn->zn_zap;
1349	zap_leaf_t *l;
1350	int err;
1351
1352	/*
1353	 * Account for the header block of the fatzap.
1354	 */
1355	if (!add && dmu_buf_freeable(zap->zap_dbuf)) {
1356		*tooverwrite += zap->zap_dbuf->db_size;
1357	} else {
1358		*towrite += zap->zap_dbuf->db_size;
1359	}
1360
1361	/*
1362	 * Account for the pointer table blocks.
1363	 * If we are adding we need to account for the following cases :
1364	 * - If the pointer table is embedded, this operation could force an
1365	 *   external pointer table.
1366	 * - If this already has an external pointer table this operation
1367	 *   could extend the table.
1368	 */
1369	if (add) {
1370		if (zap_f_phys(zap)->zap_ptrtbl.zt_blk == 0)
1371			*towrite += zap->zap_dbuf->db_size;
1372		else
1373			*towrite += (zap->zap_dbuf->db_size * 3);
1374	}
1375
1376	/*
1377	 * Now, check if the block containing leaf is freeable
1378	 * and account accordingly.
1379	 */
1380	err = zap_deref_leaf(zap, zn->zn_hash, NULL, RW_READER, &l);
1381	if (err != 0) {
1382		return (err);
1383	}
1384
1385	if (!add && dmu_buf_freeable(l->l_dbuf)) {
1386		*tooverwrite += l->l_dbuf->db_size;
1387	} else {
1388		/*
1389		 * If this an add operation, the leaf block could split.
1390		 * Hence, we need to account for an additional leaf block.
1391		 */
1392		*towrite += (add ? 2 : 1) * l->l_dbuf->db_size;
1393	}
1394
1395	zap_put_leaf(l);
1396	return (0);
1397}
1398