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, 2016 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 #include <sys/refcount.h> 84 85 #ifdef __cplusplus 86 extern "C" { 87 #endif 88 89 /* 90 * Specifies matching criteria for ZAP lookups. 91 */ 92 typedef enum matchtype 93 { 94 /* Only find an exact match (non-normalized) */ 95 MT_EXACT, 96 /* 97 * If there is an exact match, find that, otherwise find the 98 * first normalized match. 99 */ 100 MT_BEST, 101 /* 102 * Find the "first" normalized (case and Unicode form) match; 103 * the designated "first" match will not change as long as the 104 * set of entries with this normalization doesn't change. 105 */ 106 MT_FIRST 107 } matchtype_t; 108 109 typedef enum zap_flags { 110 /* Use 64-bit hash value (serialized cursors will always use 64-bits) */ 111 ZAP_FLAG_HASH64 = 1 << 0, 112 /* Key is binary, not string (zap_add_uint64() can be used) */ 113 ZAP_FLAG_UINT64_KEY = 1 << 1, 114 /* 115 * First word of key (which must be an array of uint64) is 116 * already randomly distributed. 117 */ 118 ZAP_FLAG_PRE_HASHED_KEY = 1 << 2, 119 } zap_flags_t; 120 121 /* 122 * Create a new zapobj with no attributes and return its object number. 123 * MT_EXACT will cause the zap object to only support MT_EXACT lookups, 124 * otherwise any matchtype can be used for lookups. 125 * 126 * normflags specifies what normalization will be done. values are: 127 * 0: no normalization (legacy on-disk format, supports MT_EXACT matching 128 * only) 129 * U8_TEXTPREP_TOLOWER: case normalization will be performed. 130 * MT_FIRST/MT_BEST matching will find entries that match without 131 * regard to case (eg. looking for "foo" can find an entry "Foo"). 132 * Eventually, other flags will permit unicode normalization as well. 133 */ 134 uint64_t zap_create(objset_t *ds, dmu_object_type_t ot, 135 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 136 uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot, 137 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 138 uint64_t zap_create_flags(objset_t *os, int normflags, zap_flags_t flags, 139 dmu_object_type_t ot, int leaf_blockshift, int indirect_blockshift, 140 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 141 uint64_t zap_create_link(objset_t *os, dmu_object_type_t ot, 142 uint64_t parent_obj, const char *name, dmu_tx_t *tx); 143 144 /* 145 * Initialize an already-allocated object. 146 */ 147 void mzap_create_impl(objset_t *os, uint64_t obj, int normflags, 148 zap_flags_t flags, dmu_tx_t *tx); 149 150 /* 151 * Create a new zapobj with no attributes from the given (unallocated) 152 * object number. 153 */ 154 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot, 155 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 156 int zap_create_claim_norm(objset_t *ds, uint64_t obj, 157 int normflags, dmu_object_type_t ot, 158 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 159 160 /* 161 * The zapobj passed in must be a valid ZAP object for all of the 162 * following routines. 163 */ 164 165 /* 166 * Destroy this zapobj and all its attributes. 167 * 168 * Frees the object number using dmu_object_free. 169 */ 170 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx); 171 172 /* 173 * Manipulate attributes. 174 * 175 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8. 176 */ 177 178 /* 179 * Retrieve the contents of the attribute with the given name. 180 * 181 * If the requested attribute does not exist, the call will fail and 182 * return ENOENT. 183 * 184 * If 'integer_size' is smaller than the attribute's integer size, the 185 * call will fail and return EINVAL. 186 * 187 * If 'integer_size' is equal to or larger than the attribute's integer 188 * size, the call will succeed and return 0. 189 * 190 * When converting to a larger integer size, the integers will be treated as 191 * unsigned (ie. no sign-extension will be performed). 192 * 193 * 'num_integers' is the length (in integers) of 'buf'. 194 * 195 * If the attribute is longer than the buffer, as many integers as will 196 * fit will be transferred to 'buf'. If the entire attribute was not 197 * transferred, the call will return EOVERFLOW. 198 */ 199 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name, 200 uint64_t integer_size, uint64_t num_integers, void *buf); 201 202 /* 203 * If rn_len is nonzero, realname will be set to the name of the found 204 * entry (which may be different from the requested name if matchtype is 205 * not MT_EXACT). 206 * 207 * If normalization_conflictp is not NULL, it will be set if there is 208 * another name with the same case/unicode normalized form. 209 */ 210 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name, 211 uint64_t integer_size, uint64_t num_integers, void *buf, 212 matchtype_t mt, char *realname, int rn_len, 213 boolean_t *normalization_conflictp); 214 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 215 int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf); 216 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name); 217 int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 218 int key_numints); 219 int zap_lookup_by_dnode(dnode_t *dn, const char *name, 220 uint64_t integer_size, uint64_t num_integers, void *buf); 221 int zap_lookup_norm_by_dnode(dnode_t *dn, const char *name, 222 uint64_t integer_size, uint64_t num_integers, void *buf, 223 matchtype_t mt, char *realname, int rn_len, 224 boolean_t *ncp); 225 226 int zap_count_write_by_dnode(dnode_t *dn, const char *name, 227 int add, refcount_t *towrite, refcount_t *tooverwrite); 228 229 /* 230 * Create an attribute with the given name and value. 231 * 232 * If an attribute with the given name already exists, the call will 233 * fail and return EEXIST. 234 */ 235 int zap_add(objset_t *ds, uint64_t zapobj, const char *key, 236 int integer_size, uint64_t num_integers, 237 const void *val, dmu_tx_t *tx); 238 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key, 239 int key_numints, int integer_size, uint64_t num_integers, 240 const void *val, dmu_tx_t *tx); 241 242 /* 243 * Set the attribute with the given name to the given value. If an 244 * attribute with the given name does not exist, it will be created. If 245 * an attribute with the given name already exists, the previous value 246 * will be overwritten. The integer_size may be different from the 247 * existing attribute's integer size, in which case the attribute's 248 * integer size will be updated to the new value. 249 */ 250 int zap_update(objset_t *ds, uint64_t zapobj, const char *name, 251 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 252 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 253 int key_numints, 254 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 255 256 /* 257 * Get the length (in integers) and the integer size of the specified 258 * attribute. 259 * 260 * If the requested attribute does not exist, the call will fail and 261 * return ENOENT. 262 */ 263 int zap_length(objset_t *ds, uint64_t zapobj, const char *name, 264 uint64_t *integer_size, uint64_t *num_integers); 265 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 266 int key_numints, uint64_t *integer_size, uint64_t *num_integers); 267 268 /* 269 * Remove the specified attribute. 270 * 271 * If the specified attribute does not exist, the call will fail and 272 * return ENOENT. 273 */ 274 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx); 275 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name, 276 matchtype_t mt, dmu_tx_t *tx); 277 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 278 int key_numints, dmu_tx_t *tx); 279 280 /* 281 * Returns (in *count) the number of attributes in the specified zap 282 * object. 283 */ 284 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count); 285 286 /* 287 * Returns (in name) the name of the entry whose (value & mask) 288 * (za_first_integer) is value, or ENOENT if not found. The string 289 * pointed to by name must be at least 256 bytes long. If mask==0, the 290 * match must be exact (ie, same as mask=-1ULL). 291 */ 292 int zap_value_search(objset_t *os, uint64_t zapobj, 293 uint64_t value, uint64_t mask, char *name); 294 295 /* 296 * Transfer all the entries from fromobj into intoobj. Only works on 297 * int_size=8 num_integers=1 values. Fails if there are any duplicated 298 * entries. 299 */ 300 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx); 301 302 /* Same as zap_join, but set the values to 'value'. */ 303 int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj, 304 uint64_t value, dmu_tx_t *tx); 305 306 /* Same as zap_join, but add together any duplicated entries. */ 307 int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj, 308 dmu_tx_t *tx); 309 310 /* 311 * Manipulate entries where the name + value are the "same" (the name is 312 * a stringified version of the value). 313 */ 314 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 315 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 316 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value); 317 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta, 318 dmu_tx_t *tx); 319 320 /* Here the key is an int and the value is a different int. */ 321 int zap_add_int_key(objset_t *os, uint64_t obj, 322 uint64_t key, uint64_t value, dmu_tx_t *tx); 323 int zap_update_int_key(objset_t *os, uint64_t obj, 324 uint64_t key, uint64_t value, dmu_tx_t *tx); 325 int zap_lookup_int_key(objset_t *os, uint64_t obj, 326 uint64_t key, uint64_t *valuep); 327 328 int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta, 329 dmu_tx_t *tx); 330 331 struct zap; 332 struct zap_leaf; 333 typedef struct zap_cursor { 334 /* This structure is opaque! */ 335 objset_t *zc_objset; 336 struct zap *zc_zap; 337 struct zap_leaf *zc_leaf; 338 uint64_t zc_zapobj; 339 uint64_t zc_serialized; 340 uint64_t zc_hash; 341 uint32_t zc_cd; 342 } zap_cursor_t; 343 344 typedef struct { 345 int za_integer_length; 346 /* 347 * za_normalization_conflict will be set if there are additional 348 * entries with this normalized form (eg, "foo" and "Foo"). 349 */ 350 boolean_t za_normalization_conflict; 351 uint64_t za_num_integers; 352 uint64_t za_first_integer; /* no sign extension for <8byte ints */ 353 char za_name[ZAP_MAXNAMELEN]; 354 } zap_attribute_t; 355 356 /* 357 * The interface for listing all the attributes of a zapobj can be 358 * thought of as cursor moving down a list of the attributes one by 359 * one. The cookie returned by the zap_cursor_serialize routine is 360 * persistent across system calls (and across reboot, even). 361 */ 362 363 /* 364 * Initialize a zap cursor, pointing to the "first" attribute of the 365 * zapobj. You must _fini the cursor when you are done with it. 366 */ 367 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj); 368 void zap_cursor_fini(zap_cursor_t *zc); 369 370 /* 371 * Get the attribute currently pointed to by the cursor. Returns 372 * ENOENT if at the end of the attributes. 373 */ 374 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za); 375 376 /* 377 * Advance the cursor to the next attribute. 378 */ 379 void zap_cursor_advance(zap_cursor_t *zc); 380 381 /* 382 * Get a persistent cookie pointing to the current position of the zap 383 * cursor. The low 4 bits in the cookie are always zero, and thus can 384 * be used as to differentiate a serialized cookie from a different type 385 * of value. The cookie will be less than 2^32 as long as there are 386 * fewer than 2^22 (4.2 million) entries in the zap object. 387 */ 388 uint64_t zap_cursor_serialize(zap_cursor_t *zc); 389 390 /* 391 * Advance the cursor to the attribute having the given key. 392 */ 393 int zap_cursor_move_to_key(zap_cursor_t *zc, const char *name, matchtype_t mt); 394 395 /* 396 * Initialize a zap cursor pointing to the position recorded by 397 * zap_cursor_serialize (in the "serialized" argument). You can also 398 * use a "serialized" argument of 0 to start at the beginning of the 399 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to 400 * zap_cursor_init(...).) 401 */ 402 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds, 403 uint64_t zapobj, uint64_t serialized); 404 405 406 #define ZAP_HISTOGRAM_SIZE 10 407 408 typedef struct zap_stats { 409 /* 410 * Size of the pointer table (in number of entries). 411 * This is always a power of 2, or zero if it's a microzap. 412 * In general, it should be considerably greater than zs_num_leafs. 413 */ 414 uint64_t zs_ptrtbl_len; 415 416 uint64_t zs_blocksize; /* size of zap blocks */ 417 418 /* 419 * The number of blocks used. Note that some blocks may be 420 * wasted because old ptrtbl's and large name/value blocks are 421 * not reused. (Although their space is reclaimed, we don't 422 * reuse those offsets in the object.) 423 */ 424 uint64_t zs_num_blocks; 425 426 /* 427 * Pointer table values from zap_ptrtbl in the zap_phys_t 428 */ 429 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */ 430 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */ 431 uint64_t zs_ptrtbl_zt_blk; /* starting block number */ 432 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */ 433 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */ 434 435 /* 436 * Values of the other members of the zap_phys_t 437 */ 438 uint64_t zs_block_type; /* ZBT_HEADER */ 439 uint64_t zs_magic; /* ZAP_MAGIC */ 440 uint64_t zs_num_leafs; /* The number of leaf blocks */ 441 uint64_t zs_num_entries; /* The number of zap entries */ 442 uint64_t zs_salt; /* salt to stir into hash function */ 443 444 /* 445 * Histograms. For all histograms, the last index 446 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater 447 * than what can be represented. For example 448 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number 449 * of leafs with more than 45 entries. 450 */ 451 452 /* 453 * zs_leafs_with_n_pointers[n] is the number of leafs with 454 * 2^n pointers to it. 455 */ 456 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE]; 457 458 /* 459 * zs_leafs_with_n_entries[n] is the number of leafs with 460 * [n*5, (n+1)*5) entries. In the current implementation, there 461 * can be at most 55 entries in any block, but there may be 462 * fewer if the name or value is large, or the block is not 463 * completely full. 464 */ 465 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE]; 466 467 /* 468 * zs_leafs_n_tenths_full[n] is the number of leafs whose 469 * fullness is in the range [n/10, (n+1)/10). 470 */ 471 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE]; 472 473 /* 474 * zs_entries_using_n_chunks[n] is the number of entries which 475 * consume n 24-byte chunks. (Note, large names/values only use 476 * one chunk, but contribute to zs_num_blocks_large.) 477 */ 478 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE]; 479 480 /* 481 * zs_buckets_with_n_entries[n] is the number of buckets (each 482 * leaf has 64 buckets) with n entries. 483 * zs_buckets_with_n_entries[1] should be very close to 484 * zs_num_entries. 485 */ 486 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE]; 487 } zap_stats_t; 488 489 /* 490 * Get statistics about a ZAP object. Note: you need to be aware of the 491 * internal implementation of the ZAP to correctly interpret some of the 492 * statistics. This interface shouldn't be relied on unless you really 493 * know what you're doing. 494 */ 495 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs); 496 497 #ifdef __cplusplus 498 } 499 #endif 500 501 #endif /* _SYS_ZAP_H */ 502