1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2012 by Delphix. All rights reserved. 24 */ 25 26 #ifndef _SYS_ZAP_H 27 #define _SYS_ZAP_H 28 29 /* 30 * ZAP - ZFS Attribute Processor 31 * 32 * The ZAP is a module which sits on top of the DMU (Data Management 33 * Unit) and implements a higher-level storage primitive using DMU 34 * objects. Its primary consumer is the ZPL (ZFS Posix Layer). 35 * 36 * A "zapobj" is a DMU object which the ZAP uses to stores attributes. 37 * Users should use only zap routines to access a zapobj - they should 38 * not access the DMU object directly using DMU routines. 39 * 40 * The attributes stored in a zapobj are name-value pairs. The name is 41 * a zero-terminated string of up to ZAP_MAXNAMELEN bytes (including 42 * terminating NULL). The value is an array of integers, which may be 43 * 1, 2, 4, or 8 bytes long. The total space used by the array (number 44 * of integers * integer length) can be up to ZAP_MAXVALUELEN bytes. 45 * Note that an 8-byte integer value can be used to store the location 46 * (object number) of another dmu object (which may be itself a zapobj). 47 * Note that you can use a zero-length attribute to store a single bit 48 * of information - the attribute is present or not. 49 * 50 * The ZAP routines are thread-safe. However, you must observe the 51 * DMU's restriction that a transaction may not be operated on 52 * concurrently. 53 * 54 * Any of the routines that return an int may return an I/O error (EIO 55 * or ECHECKSUM). 56 * 57 * 58 * Implementation / Performance Notes: 59 * 60 * The ZAP is intended to operate most efficiently on attributes with 61 * short (49 bytes or less) names and single 8-byte values, for which 62 * the microzap will be used. The ZAP should be efficient enough so 63 * that the user does not need to cache these attributes. 64 * 65 * The ZAP's locking scheme makes its routines thread-safe. Operations 66 * on different zapobjs will be processed concurrently. Operations on 67 * the same zapobj which only read data will be processed concurrently. 68 * Operations on the same zapobj which modify data will be processed 69 * concurrently when there are many attributes in the zapobj (because 70 * the ZAP uses per-block locking - more than 128 * (number of cpus) 71 * small attributes will suffice). 72 */ 73 74 /* 75 * We're using zero-terminated byte strings (ie. ASCII or UTF-8 C 76 * strings) for the names of attributes, rather than a byte string 77 * bounded by an explicit length. If some day we want to support names 78 * in character sets which have embedded zeros (eg. UTF-16, UTF-32), 79 * we'll have to add routines for using length-bounded strings. 80 */ 81 82 #include <sys/dmu.h> 83 84 #ifdef __cplusplus 85 extern "C" { 86 #endif 87 88 /* 89 * The matchtype specifies which entry will be accessed. 90 * MT_EXACT: only find an exact match (non-normalized) 91 * MT_FIRST: find the "first" normalized (case and Unicode 92 * form) match; the designated "first" match will not change as long 93 * as the set of entries with this normalization doesn't change 94 * MT_BEST: if there is an exact match, find that, otherwise find the 95 * first normalized match 96 */ 97 typedef enum matchtype 98 { 99 MT_EXACT, 100 MT_BEST, 101 MT_FIRST 102 } matchtype_t; 103 104 typedef enum zap_flags { 105 /* Use 64-bit hash value (serialized cursors will always use 64-bits) */ 106 ZAP_FLAG_HASH64 = 1 << 0, 107 /* Key is binary, not string (zap_add_uint64() can be used) */ 108 ZAP_FLAG_UINT64_KEY = 1 << 1, 109 /* 110 * First word of key (which must be an array of uint64) is 111 * already randomly distributed. 112 */ 113 ZAP_FLAG_PRE_HASHED_KEY = 1 << 2, 114 } zap_flags_t; 115 116 /* 117 * Create a new zapobj with no attributes and return its object number. 118 * MT_EXACT will cause the zap object to only support MT_EXACT lookups, 119 * otherwise any matchtype can be used for lookups. 120 * 121 * normflags specifies what normalization will be done. values are: 122 * 0: no normalization (legacy on-disk format, supports MT_EXACT matching 123 * only) 124 * U8_TEXTPREP_TOLOWER: case normalization will be performed. 125 * MT_FIRST/MT_BEST matching will find entries that match without 126 * regard to case (eg. looking for "foo" can find an entry "Foo"). 127 * Eventually, other flags will permit unicode normalization as well. 128 */ 129 uint64_t zap_create(objset_t *ds, dmu_object_type_t ot, 130 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 131 uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot, 132 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 133 uint64_t zap_create_flags(objset_t *os, int normflags, zap_flags_t flags, 134 dmu_object_type_t ot, int leaf_blockshift, int indirect_blockshift, 135 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 136 uint64_t zap_create_link(objset_t *os, dmu_object_type_t ot, 137 uint64_t parent_obj, const char *name, dmu_tx_t *tx); 138 139 /* 140 * Create a new zapobj with no attributes from the given (unallocated) 141 * object number. 142 */ 143 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot, 144 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 145 int zap_create_claim_norm(objset_t *ds, uint64_t obj, 146 int normflags, dmu_object_type_t ot, 147 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 148 149 /* 150 * The zapobj passed in must be a valid ZAP object for all of the 151 * following routines. 152 */ 153 154 /* 155 * Destroy this zapobj and all its attributes. 156 * 157 * Frees the object number using dmu_object_free. 158 */ 159 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx); 160 161 /* 162 * Manipulate attributes. 163 * 164 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8. 165 */ 166 167 /* 168 * Retrieve the contents of the attribute with the given name. 169 * 170 * If the requested attribute does not exist, the call will fail and 171 * return ENOENT. 172 * 173 * If 'integer_size' is smaller than the attribute's integer size, the 174 * call will fail and return EINVAL. 175 * 176 * If 'integer_size' is equal to or larger than the attribute's integer 177 * size, the call will succeed and return 0. * When converting to a 178 * larger integer size, the integers will be treated as unsigned (ie. no 179 * sign-extension will be performed). 180 * 181 * 'num_integers' is the length (in integers) of 'buf'. 182 * 183 * If the attribute is longer than the buffer, as many integers as will 184 * fit will be transferred to 'buf'. If the entire attribute was not 185 * transferred, the call will return EOVERFLOW. 186 * 187 * If rn_len is nonzero, realname will be set to the name of the found 188 * entry (which may be different from the requested name if matchtype is 189 * not MT_EXACT). 190 * 191 * If normalization_conflictp is not NULL, it will be set if there is 192 * another name with the same case/unicode normalized form. 193 */ 194 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name, 195 uint64_t integer_size, uint64_t num_integers, void *buf); 196 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name, 197 uint64_t integer_size, uint64_t num_integers, void *buf, 198 matchtype_t mt, char *realname, int rn_len, 199 boolean_t *normalization_conflictp); 200 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 201 int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf); 202 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name); 203 int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 204 int key_numints); 205 206 int zap_count_write(objset_t *os, uint64_t zapobj, const char *name, 207 int add, uint64_t *towrite, uint64_t *tooverwrite); 208 209 /* 210 * Create an attribute with the given name and value. 211 * 212 * If an attribute with the given name already exists, the call will 213 * fail and return EEXIST. 214 */ 215 int zap_add(objset_t *ds, uint64_t zapobj, const char *key, 216 int integer_size, uint64_t num_integers, 217 const void *val, dmu_tx_t *tx); 218 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key, 219 int key_numints, int integer_size, uint64_t num_integers, 220 const void *val, dmu_tx_t *tx); 221 222 /* 223 * Set the attribute with the given name to the given value. If an 224 * attribute with the given name does not exist, it will be created. If 225 * an attribute with the given name already exists, the previous value 226 * will be overwritten. The integer_size may be different from the 227 * existing attribute's integer size, in which case the attribute's 228 * integer size will be updated to the new value. 229 */ 230 int zap_update(objset_t *ds, uint64_t zapobj, const char *name, 231 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 232 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 233 int key_numints, 234 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 235 236 /* 237 * Get the length (in integers) and the integer size of the specified 238 * attribute. 239 * 240 * If the requested attribute does not exist, the call will fail and 241 * return ENOENT. 242 */ 243 int zap_length(objset_t *ds, uint64_t zapobj, const char *name, 244 uint64_t *integer_size, uint64_t *num_integers); 245 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 246 int key_numints, uint64_t *integer_size, uint64_t *num_integers); 247 248 /* 249 * Remove the specified attribute. 250 * 251 * If the specified attribute does not exist, the call will fail and 252 * return ENOENT. 253 */ 254 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx); 255 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name, 256 matchtype_t mt, dmu_tx_t *tx); 257 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 258 int key_numints, dmu_tx_t *tx); 259 260 /* 261 * Returns (in *count) the number of attributes in the specified zap 262 * object. 263 */ 264 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count); 265 266 /* 267 * Returns (in name) the name of the entry whose (value & mask) 268 * (za_first_integer) is value, or ENOENT if not found. The string 269 * pointed to by name must be at least 256 bytes long. If mask==0, the 270 * match must be exact (ie, same as mask=-1ULL). 271 */ 272 int zap_value_search(objset_t *os, uint64_t zapobj, 273 uint64_t value, uint64_t mask, char *name); 274 275 /* 276 * Transfer all the entries from fromobj into intoobj. Only works on 277 * int_size=8 num_integers=1 values. Fails if there are any duplicated 278 * entries. 279 */ 280 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx); 281 282 /* Same as zap_join, but set the values to 'value'. */ 283 int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj, 284 uint64_t value, dmu_tx_t *tx); 285 286 /* Same as zap_join, but add together any duplicated entries. */ 287 int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj, 288 dmu_tx_t *tx); 289 290 /* 291 * Manipulate entries where the name + value are the "same" (the name is 292 * a stringified version of the value). 293 */ 294 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 295 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 296 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value); 297 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta, 298 dmu_tx_t *tx); 299 300 /* Here the key is an int and the value is a different int. */ 301 int zap_add_int_key(objset_t *os, uint64_t obj, 302 uint64_t key, uint64_t value, dmu_tx_t *tx); 303 int zap_lookup_int_key(objset_t *os, uint64_t obj, 304 uint64_t key, uint64_t *valuep); 305 306 int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta, 307 dmu_tx_t *tx); 308 309 struct zap; 310 struct zap_leaf; 311 typedef struct zap_cursor { 312 /* This structure is opaque! */ 313 objset_t *zc_objset; 314 struct zap *zc_zap; 315 struct zap_leaf *zc_leaf; 316 uint64_t zc_zapobj; 317 uint64_t zc_serialized; 318 uint64_t zc_hash; 319 uint32_t zc_cd; 320 } zap_cursor_t; 321 322 typedef struct { 323 int za_integer_length; 324 /* 325 * za_normalization_conflict will be set if there are additional 326 * entries with this normalized form (eg, "foo" and "Foo"). 327 */ 328 boolean_t za_normalization_conflict; 329 uint64_t za_num_integers; 330 uint64_t za_first_integer; /* no sign extension for <8byte ints */ 331 char za_name[MAXNAMELEN]; 332 } zap_attribute_t; 333 334 /* 335 * The interface for listing all the attributes of a zapobj can be 336 * thought of as cursor moving down a list of the attributes one by 337 * one. The cookie returned by the zap_cursor_serialize routine is 338 * persistent across system calls (and across reboot, even). 339 */ 340 341 /* 342 * Initialize a zap cursor, pointing to the "first" attribute of the 343 * zapobj. You must _fini the cursor when you are done with it. 344 */ 345 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj); 346 void zap_cursor_fini(zap_cursor_t *zc); 347 348 /* 349 * Get the attribute currently pointed to by the cursor. Returns 350 * ENOENT if at the end of the attributes. 351 */ 352 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za); 353 354 /* 355 * Advance the cursor to the next attribute. 356 */ 357 void zap_cursor_advance(zap_cursor_t *zc); 358 359 /* 360 * Get a persistent cookie pointing to the current position of the zap 361 * cursor. The low 4 bits in the cookie are always zero, and thus can 362 * be used as to differentiate a serialized cookie from a different type 363 * of value. The cookie will be less than 2^32 as long as there are 364 * fewer than 2^22 (4.2 million) entries in the zap object. 365 */ 366 uint64_t zap_cursor_serialize(zap_cursor_t *zc); 367 368 /* 369 * Advance the cursor to the attribute having the given key. 370 */ 371 int zap_cursor_move_to_key(zap_cursor_t *zc, const char *name, matchtype_t mt); 372 373 /* 374 * Initialize a zap cursor pointing to the position recorded by 375 * zap_cursor_serialize (in the "serialized" argument). You can also 376 * use a "serialized" argument of 0 to start at the beginning of the 377 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to 378 * zap_cursor_init(...).) 379 */ 380 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds, 381 uint64_t zapobj, uint64_t serialized); 382 383 384 #define ZAP_HISTOGRAM_SIZE 10 385 386 typedef struct zap_stats { 387 /* 388 * Size of the pointer table (in number of entries). 389 * This is always a power of 2, or zero if it's a microzap. 390 * In general, it should be considerably greater than zs_num_leafs. 391 */ 392 uint64_t zs_ptrtbl_len; 393 394 uint64_t zs_blocksize; /* size of zap blocks */ 395 396 /* 397 * The number of blocks used. Note that some blocks may be 398 * wasted because old ptrtbl's and large name/value blocks are 399 * not reused. (Although their space is reclaimed, we don't 400 * reuse those offsets in the object.) 401 */ 402 uint64_t zs_num_blocks; 403 404 /* 405 * Pointer table values from zap_ptrtbl in the zap_phys_t 406 */ 407 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */ 408 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */ 409 uint64_t zs_ptrtbl_zt_blk; /* starting block number */ 410 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */ 411 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */ 412 413 /* 414 * Values of the other members of the zap_phys_t 415 */ 416 uint64_t zs_block_type; /* ZBT_HEADER */ 417 uint64_t zs_magic; /* ZAP_MAGIC */ 418 uint64_t zs_num_leafs; /* The number of leaf blocks */ 419 uint64_t zs_num_entries; /* The number of zap entries */ 420 uint64_t zs_salt; /* salt to stir into hash function */ 421 422 /* 423 * Histograms. For all histograms, the last index 424 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater 425 * than what can be represented. For example 426 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number 427 * of leafs with more than 45 entries. 428 */ 429 430 /* 431 * zs_leafs_with_n_pointers[n] is the number of leafs with 432 * 2^n pointers to it. 433 */ 434 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE]; 435 436 /* 437 * zs_leafs_with_n_entries[n] is the number of leafs with 438 * [n*5, (n+1)*5) entries. In the current implementation, there 439 * can be at most 55 entries in any block, but there may be 440 * fewer if the name or value is large, or the block is not 441 * completely full. 442 */ 443 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE]; 444 445 /* 446 * zs_leafs_n_tenths_full[n] is the number of leafs whose 447 * fullness is in the range [n/10, (n+1)/10). 448 */ 449 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE]; 450 451 /* 452 * zs_entries_using_n_chunks[n] is the number of entries which 453 * consume n 24-byte chunks. (Note, large names/values only use 454 * one chunk, but contribute to zs_num_blocks_large.) 455 */ 456 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE]; 457 458 /* 459 * zs_buckets_with_n_entries[n] is the number of buckets (each 460 * leaf has 64 buckets) with n entries. 461 * zs_buckets_with_n_entries[1] should be very close to 462 * zs_num_entries. 463 */ 464 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE]; 465 } zap_stats_t; 466 467 /* 468 * Get statistics about a ZAP object. Note: you need to be aware of the 469 * internal implementation of the ZAP to correctly interpret some of the 470 * statistics. This interface shouldn't be relied on unless you really 471 * know what you're doing. 472 */ 473 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs); 474 475 #ifdef __cplusplus 476 } 477 #endif 478 479 #endif /* _SYS_ZAP_H */ 480