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      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 2007 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     27 
     28 /*
     29  * The 512-byte leaf is broken into 32 16-byte chunks.
     30  * chunk number n means l_chunk[n], even though the header precedes it.
     31  * the names are stored null-terminated.
     32  */
     33 
     34 #include <sys/zfs_context.h>
     35 #include <sys/zap.h>
     36 #include <sys/zap_impl.h>
     37 #include <sys/zap_leaf.h>
     38 #include <sys/spa.h>
     39 #include <sys/dmu.h>
     40 
     41 static uint16_t *zap_leaf_rehash_entry(zap_leaf_t *l, uint16_t entry);
     42 
     43 #define	CHAIN_END 0xffff /* end of the chunk chain */
     44 
     45 /* half the (current) minimum block size */
     46 #define	MAX_ARRAY_BYTES (8<<10)
     47 
     48 #define	LEAF_HASH(l, h) \
     49 	((ZAP_LEAF_HASH_NUMENTRIES(l)-1) & \
     50 	((h) >> (64 - ZAP_LEAF_HASH_SHIFT(l)-(l)->l_phys->l_hdr.lh_prefix_len)))
     51 
     52 #define	LEAF_HASH_ENTPTR(l, h) (&(l)->l_phys->l_hash[LEAF_HASH(l, h)])
     53 
     54 
     55 static void
     56 zap_memset(void *a, int c, size_t n)
     57 {
     58 	char *cp = a;
     59 	char *cpend = cp + n;
     60 
     61 	while (cp < cpend)
     62 		*cp++ = c;
     63 }
     64 
     65 static void
     66 stv(int len, void *addr, uint64_t value)
     67 {
     68 	switch (len) {
     69 	case 1:
     70 		*(uint8_t *)addr = value;
     71 		return;
     72 	case 2:
     73 		*(uint16_t *)addr = value;
     74 		return;
     75 	case 4:
     76 		*(uint32_t *)addr = value;
     77 		return;
     78 	case 8:
     79 		*(uint64_t *)addr = value;
     80 		return;
     81 	}
     82 	ASSERT(!"bad int len");
     83 }
     84 
     85 static uint64_t
     86 ldv(int len, const void *addr)
     87 {
     88 	switch (len) {
     89 	case 1:
     90 		return (*(uint8_t *)addr);
     91 	case 2:
     92 		return (*(uint16_t *)addr);
     93 	case 4:
     94 		return (*(uint32_t *)addr);
     95 	case 8:
     96 		return (*(uint64_t *)addr);
     97 	}
     98 	ASSERT(!"bad int len");
     99 	return (0xFEEDFACEDEADBEEFULL);
    100 }
    101 
    102 void
    103 zap_leaf_byteswap(zap_leaf_phys_t *buf, int size)
    104 {
    105 	int i;
    106 	zap_leaf_t l;
    107 	l.l_bs = highbit(size)-1;
    108 	l.l_phys = buf;
    109 
    110 	buf->l_hdr.lh_block_type = 	BSWAP_64(buf->l_hdr.lh_block_type);
    111 	buf->l_hdr.lh_prefix = 		BSWAP_64(buf->l_hdr.lh_prefix);
    112 	buf->l_hdr.lh_magic = 		BSWAP_32(buf->l_hdr.lh_magic);
    113 	buf->l_hdr.lh_nfree = 		BSWAP_16(buf->l_hdr.lh_nfree);
    114 	buf->l_hdr.lh_nentries = 	BSWAP_16(buf->l_hdr.lh_nentries);
    115 	buf->l_hdr.lh_prefix_len = 	BSWAP_16(buf->l_hdr.lh_prefix_len);
    116 	buf->l_hdr.lh_freelist = 	BSWAP_16(buf->l_hdr.lh_freelist);
    117 
    118 	for (i = 0; i < ZAP_LEAF_HASH_NUMENTRIES(&l); i++)
    119 		buf->l_hash[i] = BSWAP_16(buf->l_hash[i]);
    120 
    121 	for (i = 0; i < ZAP_LEAF_NUMCHUNKS(&l); i++) {
    122 		zap_leaf_chunk_t *lc = &ZAP_LEAF_CHUNK(&l, i);
    123 		struct zap_leaf_entry *le;
    124 
    125 		switch (lc->l_free.lf_type) {
    126 		case ZAP_CHUNK_ENTRY:
    127 			le = &lc->l_entry;
    128 
    129 			le->le_type =		BSWAP_8(le->le_type);
    130 			le->le_int_size =	BSWAP_8(le->le_int_size);
    131 			le->le_next =		BSWAP_16(le->le_next);
    132 			le->le_name_chunk =	BSWAP_16(le->le_name_chunk);
    133 			le->le_name_length =	BSWAP_16(le->le_name_length);
    134 			le->le_value_chunk =	BSWAP_16(le->le_value_chunk);
    135 			le->le_value_length =	BSWAP_16(le->le_value_length);
    136 			le->le_cd =		BSWAP_32(le->le_cd);
    137 			le->le_hash =		BSWAP_64(le->le_hash);
    138 			break;
    139 		case ZAP_CHUNK_FREE:
    140 			lc->l_free.lf_type =	BSWAP_8(lc->l_free.lf_type);
    141 			lc->l_free.lf_next =	BSWAP_16(lc->l_free.lf_next);
    142 			break;
    143 		case ZAP_CHUNK_ARRAY:
    144 			lc->l_array.la_type =	BSWAP_8(lc->l_array.la_type);
    145 			lc->l_array.la_next =	BSWAP_16(lc->l_array.la_next);
    146 			/* la_array doesn't need swapping */
    147 			break;
    148 		default:
    149 			ASSERT(!"bad leaf type");
    150 		}
    151 	}
    152 }
    153 
    154 void
    155 zap_leaf_init(zap_leaf_t *l, boolean_t sort)
    156 {
    157 	int i;
    158 
    159 	l->l_bs = highbit(l->l_dbuf->db_size)-1;
    160 	zap_memset(&l->l_phys->l_hdr, 0, sizeof (struct zap_leaf_header));
    161 	zap_memset(l->l_phys->l_hash, CHAIN_END, 2*ZAP_LEAF_HASH_NUMENTRIES(l));
    162 	for (i = 0; i < ZAP_LEAF_NUMCHUNKS(l); i++) {
    163 		ZAP_LEAF_CHUNK(l, i).l_free.lf_type = ZAP_CHUNK_FREE;
    164 		ZAP_LEAF_CHUNK(l, i).l_free.lf_next = i+1;
    165 	}
    166 	ZAP_LEAF_CHUNK(l, ZAP_LEAF_NUMCHUNKS(l)-1).l_free.lf_next = CHAIN_END;
    167 	l->l_phys->l_hdr.lh_block_type = ZBT_LEAF;
    168 	l->l_phys->l_hdr.lh_magic = ZAP_LEAF_MAGIC;
    169 	l->l_phys->l_hdr.lh_nfree = ZAP_LEAF_NUMCHUNKS(l);
    170 	if (sort)
    171 		l->l_phys->l_hdr.lh_flags |= ZLF_ENTRIES_CDSORTED;
    172 }
    173 
    174 /*
    175  * Routines which manipulate leaf chunks (l_chunk[]).
    176  */
    177 
    178 static uint16_t
    179 zap_leaf_chunk_alloc(zap_leaf_t *l)
    180 {
    181 	int chunk;
    182 
    183 	ASSERT(l->l_phys->l_hdr.lh_nfree > 0);
    184 
    185 	chunk = l->l_phys->l_hdr.lh_freelist;
    186 	ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    187 	ASSERT3U(ZAP_LEAF_CHUNK(l, chunk).l_free.lf_type, ==, ZAP_CHUNK_FREE);
    188 
    189 	l->l_phys->l_hdr.lh_freelist = ZAP_LEAF_CHUNK(l, chunk).l_free.lf_next;
    190 
    191 	l->l_phys->l_hdr.lh_nfree--;
    192 
    193 	return (chunk);
    194 }
    195 
    196 static void
    197 zap_leaf_chunk_free(zap_leaf_t *l, uint16_t chunk)
    198 {
    199 	struct zap_leaf_free *zlf = &ZAP_LEAF_CHUNK(l, chunk).l_free;
    200 	ASSERT3U(l->l_phys->l_hdr.lh_nfree, <, ZAP_LEAF_NUMCHUNKS(l));
    201 	ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    202 	ASSERT(zlf->lf_type != ZAP_CHUNK_FREE);
    203 
    204 	zlf->lf_type = ZAP_CHUNK_FREE;
    205 	zlf->lf_next = l->l_phys->l_hdr.lh_freelist;
    206 	bzero(zlf->lf_pad, sizeof (zlf->lf_pad)); /* help it to compress */
    207 	l->l_phys->l_hdr.lh_freelist = chunk;
    208 
    209 	l->l_phys->l_hdr.lh_nfree++;
    210 }
    211 
    212 /*
    213  * Routines which manipulate leaf arrays (zap_leaf_array type chunks).
    214  */
    215 
    216 static uint16_t
    217 zap_leaf_array_create(zap_leaf_t *l, const char *buf,
    218 	int integer_size, int num_integers)
    219 {
    220 	uint16_t chunk_head;
    221 	uint16_t *chunkp = &chunk_head;
    222 	int byten = 0;
    223 	uint64_t value;
    224 	int shift = (integer_size-1)*8;
    225 	int len = num_integers;
    226 
    227 	ASSERT3U(num_integers * integer_size, <, MAX_ARRAY_BYTES);
    228 
    229 	while (len > 0) {
    230 		uint16_t chunk = zap_leaf_chunk_alloc(l);
    231 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
    232 		int i;
    233 
    234 		la->la_type = ZAP_CHUNK_ARRAY;
    235 		for (i = 0; i < ZAP_LEAF_ARRAY_BYTES; i++) {
    236 			if (byten == 0)
    237 				value = ldv(integer_size, buf);
    238 			la->la_array[i] = value >> shift;
    239 			value <<= 8;
    240 			if (++byten == integer_size) {
    241 				byten = 0;
    242 				buf += integer_size;
    243 				if (--len == 0)
    244 					break;
    245 			}
    246 		}
    247 
    248 		*chunkp = chunk;
    249 		chunkp = &la->la_next;
    250 	}
    251 	*chunkp = CHAIN_END;
    252 
    253 	return (chunk_head);
    254 }
    255 
    256 static void
    257 zap_leaf_array_free(zap_leaf_t *l, uint16_t *chunkp)
    258 {
    259 	uint16_t chunk = *chunkp;
    260 
    261 	*chunkp = CHAIN_END;
    262 
    263 	while (chunk != CHAIN_END) {
    264 		int nextchunk = ZAP_LEAF_CHUNK(l, chunk).l_array.la_next;
    265 		ASSERT3U(ZAP_LEAF_CHUNK(l, chunk).l_array.la_type, ==,
    266 		    ZAP_CHUNK_ARRAY);
    267 		zap_leaf_chunk_free(l, chunk);
    268 		chunk = nextchunk;
    269 	}
    270 }
    271 
    272 /* array_len and buf_len are in integers, not bytes */
    273 static void
    274 zap_leaf_array_read(zap_leaf_t *l, uint16_t chunk,
    275     int array_int_len, int array_len, int buf_int_len, uint64_t buf_len,
    276     char *buf)
    277 {
    278 	int len = MIN(array_len, buf_len);
    279 	int byten = 0;
    280 	uint64_t value = 0;
    281 
    282 	ASSERT3U(array_int_len, <=, buf_int_len);
    283 
    284 	/* Fast path for one 8-byte integer */
    285 	if (array_int_len == 8 && buf_int_len == 8 && len == 1) {
    286 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
    287 		uint8_t *ip = la->la_array;
    288 		uint64_t *buf64 = (uint64_t *)buf;
    289 
    290 		*buf64 = (uint64_t)ip[0] << 56 | (uint64_t)ip[1] << 48 |
    291 		    (uint64_t)ip[2] << 40 | (uint64_t)ip[3] << 32 |
    292 		    (uint64_t)ip[4] << 24 | (uint64_t)ip[5] << 16 |
    293 		    (uint64_t)ip[6] << 8 | (uint64_t)ip[7];
    294 		return;
    295 	}
    296 
    297 	/* Fast path for an array of 1-byte integers (eg. the entry name) */
    298 	if (array_int_len == 1 && buf_int_len == 1 &&
    299 	    buf_len > array_len + ZAP_LEAF_ARRAY_BYTES) {
    300 		while (chunk != CHAIN_END) {
    301 			struct zap_leaf_array *la =
    302 			    &ZAP_LEAF_CHUNK(l, chunk).l_array;
    303 			bcopy(la->la_array, buf, ZAP_LEAF_ARRAY_BYTES);
    304 			buf += ZAP_LEAF_ARRAY_BYTES;
    305 			chunk = la->la_next;
    306 		}
    307 		return;
    308 	}
    309 
    310 	while (len > 0) {
    311 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
    312 		int i;
    313 
    314 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    315 		for (i = 0; i < ZAP_LEAF_ARRAY_BYTES && len > 0; i++) {
    316 			value = (value << 8) | la->la_array[i];
    317 			byten++;
    318 			if (byten == array_int_len) {
    319 				stv(buf_int_len, buf, value);
    320 				byten = 0;
    321 				len--;
    322 				if (len == 0)
    323 					return;
    324 				buf += buf_int_len;
    325 			}
    326 		}
    327 		chunk = la->la_next;
    328 	}
    329 }
    330 
    331 /*
    332  * Only to be used on 8-bit arrays.
    333  * array_len is actual len in bytes (not encoded le_value_length).
    334  * namenorm is null-terminated.
    335  */
    336 static boolean_t
    337 zap_leaf_array_match(zap_leaf_t *l, zap_name_t *zn, int chunk, int array_len)
    338 {
    339 	int bseen = 0;
    340 
    341 	if (zn->zn_matchtype == MT_FIRST) {
    342 		char *thisname = kmem_alloc(array_len, KM_SLEEP);
    343 		boolean_t match;
    344 
    345 		zap_leaf_array_read(l, chunk, 1, array_len, 1,
    346 		    array_len, thisname);
    347 		match = zap_match(zn, thisname);
    348 		kmem_free(thisname, array_len);
    349 		return (match);
    350 	}
    351 
    352 	/* Fast path for exact matching */
    353 	while (bseen < array_len) {
    354 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
    355 		int toread = MIN(array_len - bseen, ZAP_LEAF_ARRAY_BYTES);
    356 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    357 		if (bcmp(la->la_array, zn->zn_name_orij + bseen, toread))
    358 			break;
    359 		chunk = la->la_next;
    360 		bseen += toread;
    361 	}
    362 	return (bseen == array_len);
    363 }
    364 
    365 /*
    366  * Routines which manipulate leaf entries.
    367  */
    368 
    369 int
    370 zap_leaf_lookup(zap_leaf_t *l, zap_name_t *zn, zap_entry_handle_t *zeh)
    371 {
    372 	uint16_t *chunkp;
    373 	struct zap_leaf_entry *le;
    374 
    375 	ASSERT3U(l->l_phys->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);
    376 
    377 again:
    378 	for (chunkp = LEAF_HASH_ENTPTR(l, zn->zn_hash);
    379 	    *chunkp != CHAIN_END; chunkp = &le->le_next) {
    380 		uint16_t chunk = *chunkp;
    381 		le = ZAP_LEAF_ENTRY(l, chunk);
    382 
    383 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    384 		ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);
    385 
    386 		if (le->le_hash != zn->zn_hash)
    387 			continue;
    388 
    389 		/*
    390 		 * NB: the entry chain is always sorted by cd on
    391 		 * normalized zap objects, so this will find the
    392 		 * lowest-cd match for MT_FIRST.
    393 		 */
    394 		ASSERT(zn->zn_matchtype == MT_EXACT ||
    395 		    (l->l_phys->l_hdr.lh_flags & ZLF_ENTRIES_CDSORTED));
    396 		if (zap_leaf_array_match(l, zn, le->le_name_chunk,
    397 		    le->le_name_length)) {
    398 			zeh->zeh_num_integers = le->le_value_length;
    399 			zeh->zeh_integer_size = le->le_int_size;
    400 			zeh->zeh_cd = le->le_cd;
    401 			zeh->zeh_hash = le->le_hash;
    402 			zeh->zeh_chunkp = chunkp;
    403 			zeh->zeh_leaf = l;
    404 			return (0);
    405 		}
    406 	}
    407 
    408 	/*
    409 	 * NB: we could of course do this in one pass, but that would be
    410 	 * a pain.  We'll see if MT_BEST is even used much.
    411 	 */
    412 	if (zn->zn_matchtype == MT_BEST) {
    413 		zn->zn_matchtype = MT_FIRST;
    414 		goto again;
    415 	}
    416 
    417 	return (ENOENT);
    418 }
    419 
    420 /* Return (h1,cd1 >= h2,cd2) */
    421 #define	HCD_GTEQ(h1, cd1, h2, cd2) \
    422 	((h1 > h2) ? TRUE : ((h1 == h2 && cd1 >= cd2) ? TRUE : FALSE))
    423 
    424 int
    425 zap_leaf_lookup_closest(zap_leaf_t *l,
    426     uint64_t h, uint32_t cd, zap_entry_handle_t *zeh)
    427 {
    428 	uint16_t chunk;
    429 	uint64_t besth = -1ULL;
    430 	uint32_t bestcd = ZAP_MAXCD;
    431 	uint16_t bestlh = ZAP_LEAF_HASH_NUMENTRIES(l)-1;
    432 	uint16_t lh;
    433 	struct zap_leaf_entry *le;
    434 
    435 	ASSERT3U(l->l_phys->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);
    436 
    437 	for (lh = LEAF_HASH(l, h); lh <= bestlh; lh++) {
    438 		for (chunk = l->l_phys->l_hash[lh];
    439 		    chunk != CHAIN_END; chunk = le->le_next) {
    440 			le = ZAP_LEAF_ENTRY(l, chunk);
    441 
    442 			ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    443 			ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);
    444 
    445 			if (HCD_GTEQ(le->le_hash, le->le_cd, h, cd) &&
    446 			    HCD_GTEQ(besth, bestcd, le->le_hash, le->le_cd)) {
    447 				ASSERT3U(bestlh, >=, lh);
    448 				bestlh = lh;
    449 				besth = le->le_hash;
    450 				bestcd = le->le_cd;
    451 
    452 				zeh->zeh_num_integers = le->le_value_length;
    453 				zeh->zeh_integer_size = le->le_int_size;
    454 				zeh->zeh_cd = le->le_cd;
    455 				zeh->zeh_hash = le->le_hash;
    456 				zeh->zeh_fakechunk = chunk;
    457 				zeh->zeh_chunkp = &zeh->zeh_fakechunk;
    458 				zeh->zeh_leaf = l;
    459 			}
    460 		}
    461 	}
    462 
    463 	return (bestcd == ZAP_MAXCD ? ENOENT : 0);
    464 }
    465 
    466 int
    467 zap_entry_read(const zap_entry_handle_t *zeh,
    468     uint8_t integer_size, uint64_t num_integers, void *buf)
    469 {
    470 	struct zap_leaf_entry *le =
    471 	    ZAP_LEAF_ENTRY(zeh->zeh_leaf, *zeh->zeh_chunkp);
    472 	ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);
    473 
    474 	if (le->le_int_size > integer_size)
    475 		return (EINVAL);
    476 
    477 	zap_leaf_array_read(zeh->zeh_leaf, le->le_value_chunk, le->le_int_size,
    478 	    le->le_value_length, integer_size, num_integers, buf);
    479 
    480 	if (zeh->zeh_num_integers > num_integers)
    481 		return (EOVERFLOW);
    482 	return (0);
    483 
    484 }
    485 
    486 int
    487 zap_entry_read_name(const zap_entry_handle_t *zeh, uint16_t buflen, char *buf)
    488 {
    489 	struct zap_leaf_entry *le =
    490 	    ZAP_LEAF_ENTRY(zeh->zeh_leaf, *zeh->zeh_chunkp);
    491 	ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);
    492 
    493 	zap_leaf_array_read(zeh->zeh_leaf, le->le_name_chunk, 1,
    494 	    le->le_name_length, 1, buflen, buf);
    495 	if (le->le_name_length > buflen)
    496 		return (EOVERFLOW);
    497 	return (0);
    498 }
    499 
    500 int
    501 zap_entry_update(zap_entry_handle_t *zeh,
    502 	uint8_t integer_size, uint64_t num_integers, const void *buf)
    503 {
    504 	int delta_chunks;
    505 	zap_leaf_t *l = zeh->zeh_leaf;
    506 	struct zap_leaf_entry *le = ZAP_LEAF_ENTRY(l, *zeh->zeh_chunkp);
    507 
    508 	delta_chunks = ZAP_LEAF_ARRAY_NCHUNKS(num_integers * integer_size) -
    509 	    ZAP_LEAF_ARRAY_NCHUNKS(le->le_value_length * le->le_int_size);
    510 
    511 	if ((int)l->l_phys->l_hdr.lh_nfree < delta_chunks)
    512 		return (EAGAIN);
    513 
    514 	/*
    515 	 * We should search other chained leaves (via
    516 	 * zap_entry_remove,create?) otherwise returning EAGAIN will
    517 	 * just send us into an infinite loop if we have to chain
    518 	 * another leaf block, rather than being able to split this
    519 	 * block.
    520 	 */
    521 
    522 	zap_leaf_array_free(l, &le->le_value_chunk);
    523 	le->le_value_chunk =
    524 	    zap_leaf_array_create(l, buf, integer_size, num_integers);
    525 	le->le_value_length = num_integers;
    526 	le->le_int_size = integer_size;
    527 	return (0);
    528 }
    529 
    530 void
    531 zap_entry_remove(zap_entry_handle_t *zeh)
    532 {
    533 	uint16_t entry_chunk;
    534 	struct zap_leaf_entry *le;
    535 	zap_leaf_t *l = zeh->zeh_leaf;
    536 
    537 	ASSERT3P(zeh->zeh_chunkp, !=, &zeh->zeh_fakechunk);
    538 
    539 	entry_chunk = *zeh->zeh_chunkp;
    540 	le = ZAP_LEAF_ENTRY(l, entry_chunk);
    541 	ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);
    542 
    543 	zap_leaf_array_free(l, &le->le_name_chunk);
    544 	zap_leaf_array_free(l, &le->le_value_chunk);
    545 
    546 	*zeh->zeh_chunkp = le->le_next;
    547 	zap_leaf_chunk_free(l, entry_chunk);
    548 
    549 	l->l_phys->l_hdr.lh_nentries--;
    550 }
    551 
    552 int
    553 zap_entry_create(zap_leaf_t *l, const char *name, uint64_t h, uint32_t cd,
    554     uint8_t integer_size, uint64_t num_integers, const void *buf,
    555     zap_entry_handle_t *zeh)
    556 {
    557 	uint16_t chunk;
    558 	uint16_t *chunkp;
    559 	struct zap_leaf_entry *le;
    560 	uint64_t namelen, valuelen;
    561 	int numchunks;
    562 
    563 	valuelen = integer_size * num_integers;
    564 	namelen = strlen(name) + 1;
    565 	ASSERT(namelen >= 2);
    566 
    567 	numchunks = 1 + ZAP_LEAF_ARRAY_NCHUNKS(namelen) +
    568 	    ZAP_LEAF_ARRAY_NCHUNKS(valuelen);
    569 	if (numchunks > ZAP_LEAF_NUMCHUNKS(l))
    570 		return (E2BIG);
    571 
    572 	if (cd == ZAP_MAXCD) {
    573 		/* find the lowest unused cd */
    574 		if (l->l_phys->l_hdr.lh_flags & ZLF_ENTRIES_CDSORTED) {
    575 			cd = 0;
    576 
    577 			for (chunk = *LEAF_HASH_ENTPTR(l, h);
    578 			    chunk != CHAIN_END; chunk = le->le_next) {
    579 				le = ZAP_LEAF_ENTRY(l, chunk);
    580 				if (le->le_cd > cd)
    581 					break;
    582 				if (le->le_hash == h) {
    583 					ASSERT3U(cd, ==, le->le_cd);
    584 					cd++;
    585 				}
    586 			}
    587 		} else {
    588 			/* old unsorted format; do it the O(n^2) way */
    589 			for (cd = 0; cd < ZAP_MAXCD; cd++) {
    590 				for (chunk = *LEAF_HASH_ENTPTR(l, h);
    591 				    chunk != CHAIN_END; chunk = le->le_next) {
    592 					le = ZAP_LEAF_ENTRY(l, chunk);
    593 					if (le->le_hash == h &&
    594 					    le->le_cd == cd) {
    595 						break;
    596 					}
    597 				}
    598 				/* If this cd is not in use, we are good. */
    599 				if (chunk == CHAIN_END)
    600 					break;
    601 			}
    602 		}
    603 		/*
    604 		 * we would run out of space in a block before we could
    605 		 * have ZAP_MAXCD entries
    606 		 */
    607 		ASSERT3U(cd, <, ZAP_MAXCD);
    608 	}
    609 
    610 	if (l->l_phys->l_hdr.lh_nfree < numchunks)
    611 		return (EAGAIN);
    612 
    613 	/* make the entry */
    614 	chunk = zap_leaf_chunk_alloc(l);
    615 	le = ZAP_LEAF_ENTRY(l, chunk);
    616 	le->le_type = ZAP_CHUNK_ENTRY;
    617 	le->le_name_chunk = zap_leaf_array_create(l, name, 1, namelen);
    618 	le->le_name_length = namelen;
    619 	le->le_value_chunk =
    620 	    zap_leaf_array_create(l, buf, integer_size, num_integers);
    621 	le->le_value_length = num_integers;
    622 	le->le_int_size = integer_size;
    623 	le->le_hash = h;
    624 	le->le_cd = cd;
    625 
    626 	/* link it into the hash chain */
    627 	/* XXX if we did the search above, we could just use that */
    628 	chunkp = zap_leaf_rehash_entry(l, chunk);
    629 
    630 	l->l_phys->l_hdr.lh_nentries++;
    631 
    632 	zeh->zeh_leaf = l;
    633 	zeh->zeh_num_integers = num_integers;
    634 	zeh->zeh_integer_size = le->le_int_size;
    635 	zeh->zeh_cd = le->le_cd;
    636 	zeh->zeh_hash = le->le_hash;
    637 	zeh->zeh_chunkp = chunkp;
    638 
    639 	return (0);
    640 }
    641 
    642 /*
    643  * Determine if there is another entry with the same normalized form.
    644  * For performance purposes, either zn or name must be provided (the
    645  * other can be NULL).  Note, there usually won't be any hash
    646  * conflicts, in which case we don't need the concatenated/normalized
    647  * form of the name.  But all callers have one of these on hand anyway,
    648  * so might as well take advantage.  A cleaner but slower interface
    649  * would accept neither argument, and compute the normalized name as
    650  * needed (using zap_name_alloc(zap_entry_read_name(zeh))).
    651  */
    652 boolean_t
    653 zap_entry_normalization_conflict(zap_entry_handle_t *zeh, zap_name_t *zn,
    654     const char *name, zap_t *zap)
    655 {
    656 	uint64_t chunk;
    657 	struct zap_leaf_entry *le;
    658 	boolean_t allocdzn = B_FALSE;
    659 
    660 	if (zap->zap_normflags == 0)
    661 		return (B_FALSE);
    662 
    663 	for (chunk = *LEAF_HASH_ENTPTR(zeh->zeh_leaf, zeh->zeh_hash);
    664 	    chunk != CHAIN_END; chunk = le->le_next) {
    665 		le = ZAP_LEAF_ENTRY(zeh->zeh_leaf, chunk);
    666 		if (le->le_hash != zeh->zeh_hash)
    667 			continue;
    668 		if (le->le_cd == zeh->zeh_cd)
    669 			continue;
    670 
    671 		if (zn == NULL) {
    672 			zn = zap_name_alloc(zap, name, MT_FIRST);
    673 			allocdzn = B_TRUE;
    674 		}
    675 		if (zap_leaf_array_match(zeh->zeh_leaf, zn,
    676 		    le->le_name_chunk, le->le_name_length)) {
    677 			if (allocdzn)
    678 				zap_name_free(zn);
    679 			return (B_TRUE);
    680 		}
    681 	}
    682 	if (allocdzn)
    683 		zap_name_free(zn);
    684 	return (B_FALSE);
    685 }
    686 
    687 /*
    688  * Routines for transferring entries between leafs.
    689  */
    690 
    691 static uint16_t *
    692 zap_leaf_rehash_entry(zap_leaf_t *l, uint16_t entry)
    693 {
    694 	struct zap_leaf_entry *le = ZAP_LEAF_ENTRY(l, entry);
    695 	struct zap_leaf_entry *le2;
    696 	uint16_t *chunkp;
    697 
    698 	/*
    699 	 * keep the entry chain sorted by cd
    700 	 * NB: this will not cause problems for unsorted leafs, though
    701 	 * it is unnecessary there.
    702 	 */
    703 	for (chunkp = LEAF_HASH_ENTPTR(l, le->le_hash);
    704 	    *chunkp != CHAIN_END; chunkp = &le2->le_next) {
    705 		le2 = ZAP_LEAF_ENTRY(l, *chunkp);
    706 		if (le2->le_cd > le->le_cd)
    707 			break;
    708 	}
    709 
    710 	le->le_next = *chunkp;
    711 	*chunkp = entry;
    712 	return (chunkp);
    713 }
    714 
    715 static uint16_t
    716 zap_leaf_transfer_array(zap_leaf_t *l, uint16_t chunk, zap_leaf_t *nl)
    717 {
    718 	uint16_t new_chunk;
    719 	uint16_t *nchunkp = &new_chunk;
    720 
    721 	while (chunk != CHAIN_END) {
    722 		uint16_t nchunk = zap_leaf_chunk_alloc(nl);
    723 		struct zap_leaf_array *nla =
    724 		    &ZAP_LEAF_CHUNK(nl, nchunk).l_array;
    725 		struct zap_leaf_array *la =
    726 		    &ZAP_LEAF_CHUNK(l, chunk).l_array;
    727 		int nextchunk = la->la_next;
    728 
    729 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
    730 		ASSERT3U(nchunk, <, ZAP_LEAF_NUMCHUNKS(l));
    731 
    732 		*nla = *la; /* structure assignment */
    733 
    734 		zap_leaf_chunk_free(l, chunk);
    735 		chunk = nextchunk;
    736 		*nchunkp = nchunk;
    737 		nchunkp = &nla->la_next;
    738 	}
    739 	*nchunkp = CHAIN_END;
    740 	return (new_chunk);
    741 }
    742 
    743 static void
    744 zap_leaf_transfer_entry(zap_leaf_t *l, int entry, zap_leaf_t *nl)
    745 {
    746 	struct zap_leaf_entry *le, *nle;
    747 	uint16_t chunk;
    748 
    749 	le = ZAP_LEAF_ENTRY(l, entry);
    750 	ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);
    751 
    752 	chunk = zap_leaf_chunk_alloc(nl);
    753 	nle = ZAP_LEAF_ENTRY(nl, chunk);
    754 	*nle = *le; /* structure assignment */
    755 
    756 	(void) zap_leaf_rehash_entry(nl, chunk);
    757 
    758 	nle->le_name_chunk = zap_leaf_transfer_array(l, le->le_name_chunk, nl);
    759 	nle->le_value_chunk =
    760 	    zap_leaf_transfer_array(l, le->le_value_chunk, nl);
    761 
    762 	zap_leaf_chunk_free(l, entry);
    763 
    764 	l->l_phys->l_hdr.lh_nentries--;
    765 	nl->l_phys->l_hdr.lh_nentries++;
    766 }
    767 
    768 /*
    769  * Transfer the entries whose hash prefix ends in 1 to the new leaf.
    770  */
    771 void
    772 zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort)
    773 {
    774 	int i;
    775 	int bit = 64 - 1 - l->l_phys->l_hdr.lh_prefix_len;
    776 
    777 	/* set new prefix and prefix_len */
    778 	l->l_phys->l_hdr.lh_prefix <<= 1;
    779 	l->l_phys->l_hdr.lh_prefix_len++;
    780 	nl->l_phys->l_hdr.lh_prefix = l->l_phys->l_hdr.lh_prefix | 1;
    781 	nl->l_phys->l_hdr.lh_prefix_len = l->l_phys->l_hdr.lh_prefix_len;
    782 
    783 	/* break existing hash chains */
    784 	zap_memset(l->l_phys->l_hash, CHAIN_END, 2*ZAP_LEAF_HASH_NUMENTRIES(l));
    785 
    786 	if (sort)
    787 		l->l_phys->l_hdr.lh_flags |= ZLF_ENTRIES_CDSORTED;
    788 
    789 	/*
    790 	 * Transfer entries whose hash bit 'bit' is set to nl; rehash
    791 	 * the remaining entries
    792 	 *
    793 	 * NB: We could find entries via the hashtable instead. That
    794 	 * would be O(hashents+numents) rather than O(numblks+numents),
    795 	 * but this accesses memory more sequentially, and when we're
    796 	 * called, the block is usually pretty full.
    797 	 */
    798 	for (i = 0; i < ZAP_LEAF_NUMCHUNKS(l); i++) {
    799 		struct zap_leaf_entry *le = ZAP_LEAF_ENTRY(l, i);
    800 		if (le->le_type != ZAP_CHUNK_ENTRY)
    801 			continue;
    802 
    803 		if (le->le_hash & (1ULL << bit))
    804 			zap_leaf_transfer_entry(l, i, nl);
    805 		else
    806 			(void) zap_leaf_rehash_entry(l, i);
    807 	}
    808 }
    809 
    810 void
    811 zap_leaf_stats(zap_t *zap, zap_leaf_t *l, zap_stats_t *zs)
    812 {
    813 	int i, n;
    814 
    815 	n = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift -
    816 	    l->l_phys->l_hdr.lh_prefix_len;
    817 	n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
    818 	zs->zs_leafs_with_2n_pointers[n]++;
    819 
    820 
    821 	n = l->l_phys->l_hdr.lh_nentries/5;
    822 	n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
    823 	zs->zs_blocks_with_n5_entries[n]++;
    824 
    825 	n = ((1<<FZAP_BLOCK_SHIFT(zap)) -
    826 	    l->l_phys->l_hdr.lh_nfree * (ZAP_LEAF_ARRAY_BYTES+1))*10 /
    827 	    (1<<FZAP_BLOCK_SHIFT(zap));
    828 	n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
    829 	zs->zs_blocks_n_tenths_full[n]++;
    830 
    831 	for (i = 0; i < ZAP_LEAF_HASH_NUMENTRIES(l); i++) {
    832 		int nentries = 0;
    833 		int chunk = l->l_phys->l_hash[i];
    834 
    835 		while (chunk != CHAIN_END) {
    836 			struct zap_leaf_entry *le =
    837 			    ZAP_LEAF_ENTRY(l, chunk);
    838 
    839 			n = 1 + ZAP_LEAF_ARRAY_NCHUNKS(le->le_name_length) +
    840 			    ZAP_LEAF_ARRAY_NCHUNKS(le->le_value_length *
    841 			    le->le_int_size);
    842 			n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
    843 			zs->zs_entries_using_n_chunks[n]++;
    844 
    845 			chunk = le->le_next;
    846 			nentries++;
    847 		}
    848 
    849 		n = nentries;
    850 		n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
    851 		zs->zs_buckets_with_n_entries[n]++;
    852 	}
    853 }
    854