xref: /illumos-gate/usr/src/uts/common/fs/zfs/zap.c (revision 0c779ad424a92a84d1e07d47cab7f8009189202b)
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 
52 int fzap_default_block_shift = 14; /* 16k blocksize */
53 
54 extern inline zap_phys_t *zap_f_phys(zap_t *zap);
55 
56 static uint64_t zap_allocate_blocks(zap_t *zap, int nblocks);
57 
58 void
59 fzap_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 
73 void
74 fzap_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 
127 static int
128 zap_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 
143 static int
144 zap_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 
219 static int
220 zap_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 
267 static int
268 zap_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 
308 static void
309 zap_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 
319 static int
320 zap_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 
371 static void
372 zap_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 
381 static uint64_t
382 zap_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 
391 static void
392 zap_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 
400 static zap_leaf_t *
401 zap_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 
428 int
429 fzap_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 
442 void
443 zap_put_leaf(zap_leaf_t *l)
444 {
445 	rw_exit(&l->l_rwlock);
446 	dmu_buf_rele(l->l_dbuf, NULL);
447 }
448 
449 static zap_leaf_t *
450 zap_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 
497 static int
498 zap_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 
539 static int
540 zap_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 
555 static int
556 zap_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 
570 static int
571 zap_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 
598 static int
599 zap_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 
685 static void
686 zap_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 
720 static int
721 fzap_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 
728 static int
729 fzap_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 
748 static int
749 fzap_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  */
761 int
762 fzap_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 
795 int
796 fzap_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);
812 retry:
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 
833 out:
834 	if (zap != NULL)
835 		zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
836 	return (err);
837 }
838 
839 int
840 fzap_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 
852 int
853 fzap_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);
869 retry:
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 
895 int
896 fzap_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;
914 out:
915 	zap_put_leaf(l);
916 	return (err);
917 }
918 
919 int
920 fzap_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 
938 void
939 fzap_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 
958 uint64_t
959 zap_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 
971 int
972 zap_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 
996 int
997 zap_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 
1020 int
1021 zap_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 
1045 int
1046 zap_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 
1076 int
1077 zap_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 
1085 int
1086 zap_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 
1094 int
1095 zap_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 
1103 int
1104 zap_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 
1113 int
1114 zap_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 
1123 int
1124 zap_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 
1132 int
1133 zap_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 
1153 int
1154 zap_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 
1167 int
1168 fzap_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 
1186 again:
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 
1237 static void
1238 zap_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 
1263 void
1264 fzap_get_stats(zap_t *zap, zap_stats_t *zs)
1265 {
1266 	int bs = FZAP_BLOCK_SHIFT(zap);
1267 	zs->zs_blocksize = 1ULL << bs;
1268 
1269 	/*
1270 	 * Set zap_phys_t fields
1271 	 */
1272 	zs->zs_num_leafs = zap_f_phys(zap)->zap_num_leafs;
1273 	zs->zs_num_entries = zap_f_phys(zap)->zap_num_entries;
1274 	zs->zs_num_blocks = zap_f_phys(zap)->zap_freeblk;
1275 	zs->zs_block_type = zap_f_phys(zap)->zap_block_type;
1276 	zs->zs_magic = zap_f_phys(zap)->zap_magic;
1277 	zs->zs_salt = zap_f_phys(zap)->zap_salt;
1278 
1279 	/*
1280 	 * Set zap_ptrtbl fields
1281 	 */
1282 	zs->zs_ptrtbl_len = 1ULL << zap_f_phys(zap)->zap_ptrtbl.zt_shift;
1283 	zs->zs_ptrtbl_nextblk = zap_f_phys(zap)->zap_ptrtbl.zt_nextblk;
1284 	zs->zs_ptrtbl_blks_copied =
1285 	    zap_f_phys(zap)->zap_ptrtbl.zt_blks_copied;
1286 	zs->zs_ptrtbl_zt_blk = zap_f_phys(zap)->zap_ptrtbl.zt_blk;
1287 	zs->zs_ptrtbl_zt_numblks = zap_f_phys(zap)->zap_ptrtbl.zt_numblks;
1288 	zs->zs_ptrtbl_zt_shift = zap_f_phys(zap)->zap_ptrtbl.zt_shift;
1289 
1290 	if (zap_f_phys(zap)->zap_ptrtbl.zt_numblks == 0) {
1291 		/* the ptrtbl is entirely in the header block. */
1292 		zap_stats_ptrtbl(zap, &ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
1293 		    1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap), zs);
1294 	} else {
1295 		int b;
1296 
1297 		dmu_prefetch(zap->zap_objset, zap->zap_object, 0,
1298 		    zap_f_phys(zap)->zap_ptrtbl.zt_blk << bs,
1299 		    zap_f_phys(zap)->zap_ptrtbl.zt_numblks << bs,
1300 		    ZIO_PRIORITY_SYNC_READ);
1301 
1302 		for (b = 0; b < zap_f_phys(zap)->zap_ptrtbl.zt_numblks;
1303 		    b++) {
1304 			dmu_buf_t *db;
1305 			int err;
1306 
1307 			err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
1308 			    (zap_f_phys(zap)->zap_ptrtbl.zt_blk + b) << bs,
1309 			    FTAG, &db, DMU_READ_NO_PREFETCH);
1310 			if (err == 0) {
1311 				zap_stats_ptrtbl(zap, db->db_data,
1312 				    1<<(bs-3), zs);
1313 				dmu_buf_rele(db, FTAG);
1314 			}
1315 		}
1316 	}
1317 }
1318 
1319 int
1320 fzap_count_write(zap_name_t *zn, int add, refcount_t *towrite,
1321     refcount_t *tooverwrite)
1322 {
1323 	zap_t *zap = zn->zn_zap;
1324 	zap_leaf_t *l;
1325 	int err;
1326 
1327 	/*
1328 	 * Account for the header block of the fatzap.
1329 	 */
1330 	if (!add && dmu_buf_freeable(zap->zap_dbuf)) {
1331 		(void) refcount_add_many(tooverwrite,
1332 		    zap->zap_dbuf->db_size, FTAG);
1333 	} else {
1334 		(void) refcount_add_many(towrite,
1335 		    zap->zap_dbuf->db_size, FTAG);
1336 	}
1337 
1338 	/*
1339 	 * Account for the pointer table blocks.
1340 	 * If we are adding we need to account for the following cases :
1341 	 * - If the pointer table is embedded, this operation could force an
1342 	 *   external pointer table.
1343 	 * - If this already has an external pointer table this operation
1344 	 *   could extend the table.
1345 	 */
1346 	if (add) {
1347 		if (zap_f_phys(zap)->zap_ptrtbl.zt_blk == 0) {
1348 			(void) refcount_add_many(towrite,
1349 			    zap->zap_dbuf->db_size, FTAG);
1350 		} else {
1351 			(void) refcount_add_many(towrite,
1352 			    zap->zap_dbuf->db_size * 3, FTAG);
1353 		}
1354 	}
1355 
1356 	/*
1357 	 * Now, check if the block containing leaf is freeable
1358 	 * and account accordingly.
1359 	 */
1360 	err = zap_deref_leaf(zap, zn->zn_hash, NULL, RW_READER, &l);
1361 	if (err != 0) {
1362 		return (err);
1363 	}
1364 
1365 	if (!add && dmu_buf_freeable(l->l_dbuf)) {
1366 		(void) refcount_add_many(tooverwrite, l->l_dbuf->db_size, FTAG);
1367 	} else {
1368 		/*
1369 		 * If this an add operation, the leaf block could split.
1370 		 * Hence, we need to account for an additional leaf block.
1371 		 */
1372 		(void) refcount_add_many(towrite,
1373 		    (add ? 2 : 1) * l->l_dbuf->db_size, FTAG);
1374 	}
1375 
1376 	zap_put_leaf(l);
1377 	return (0);
1378 }
1379