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 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 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); 136 137 /* 138 * Create a new zapobj with no attributes from the given (unallocated) 139 * object number. 140 */ 141 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot, 142 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 143 int zap_create_claim_norm(objset_t *ds, uint64_t obj, 144 int normflags, dmu_object_type_t ot, 145 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 146 147 /* 148 * The zapobj passed in must be a valid ZAP object for all of the 149 * following routines. 150 */ 151 152 /* 153 * Destroy this zapobj and all its attributes. 154 * 155 * Frees the object number using dmu_object_free. 156 */ 157 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx); 158 159 /* 160 * Manipulate attributes. 161 * 162 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8. 163 */ 164 165 /* 166 * Retrieve the contents of the attribute with the given name. 167 * 168 * If the requested attribute does not exist, the call will fail and 169 * return ENOENT. 170 * 171 * If 'integer_size' is smaller than the attribute's integer size, the 172 * call will fail and return EINVAL. 173 * 174 * If 'integer_size' is equal to or larger than the attribute's integer 175 * size, the call will succeed and return 0. * When converting to a 176 * larger integer size, the integers will be treated as unsigned (ie. no 177 * sign-extension will be performed). 178 * 179 * 'num_integers' is the length (in integers) of 'buf'. 180 * 181 * If the attribute is longer than the buffer, as many integers as will 182 * fit will be transferred to 'buf'. If the entire attribute was not 183 * transferred, the call will return EOVERFLOW. 184 * 185 * If rn_len is nonzero, realname will be set to the name of the found 186 * entry (which may be different from the requested name if matchtype is 187 * not MT_EXACT). 188 * 189 * If normalization_conflictp is not NULL, it will be set if there is 190 * another name with the same case/unicode normalized form. 191 */ 192 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name, 193 uint64_t integer_size, uint64_t num_integers, void *buf); 194 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name, 195 uint64_t integer_size, uint64_t num_integers, void *buf, 196 matchtype_t mt, char *realname, int rn_len, 197 boolean_t *normalization_conflictp); 198 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 199 int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf); 200 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name); 201 202 int zap_count_write(objset_t *os, uint64_t zapobj, const char *name, 203 int add, uint64_t *towrite, uint64_t *tooverwrite); 204 205 /* 206 * Create an attribute with the given name and value. 207 * 208 * If an attribute with the given name already exists, the call will 209 * fail and return EEXIST. 210 */ 211 int zap_add(objset_t *ds, uint64_t zapobj, const char *key, 212 int integer_size, uint64_t num_integers, 213 const void *val, dmu_tx_t *tx); 214 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key, 215 int key_numints, int integer_size, uint64_t num_integers, 216 const void *val, dmu_tx_t *tx); 217 218 /* 219 * Set the attribute with the given name to the given value. If an 220 * attribute with the given name does not exist, it will be created. If 221 * an attribute with the given name already exists, the previous value 222 * will be overwritten. The integer_size may be different from the 223 * existing attribute's integer size, in which case the attribute's 224 * integer size will be updated to the new value. 225 */ 226 int zap_update(objset_t *ds, uint64_t zapobj, const char *name, 227 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 228 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 229 int key_numints, 230 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 231 232 /* 233 * Get the length (in integers) and the integer size of the specified 234 * attribute. 235 * 236 * If the requested attribute does not exist, the call will fail and 237 * return ENOENT. 238 */ 239 int zap_length(objset_t *ds, uint64_t zapobj, const char *name, 240 uint64_t *integer_size, uint64_t *num_integers); 241 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 242 int key_numints, uint64_t *integer_size, uint64_t *num_integers); 243 244 /* 245 * Remove the specified attribute. 246 * 247 * If the specified attribute does not exist, the call will fail and 248 * return ENOENT. 249 */ 250 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx); 251 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name, 252 matchtype_t mt, dmu_tx_t *tx); 253 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, 254 int key_numints, dmu_tx_t *tx); 255 256 /* 257 * Returns (in *count) the number of attributes in the specified zap 258 * object. 259 */ 260 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count); 261 262 263 /* 264 * Returns (in name) the name of the entry whose (value & mask) 265 * (za_first_integer) is value, or ENOENT if not found. The string 266 * pointed to by name must be at least 256 bytes long. If mask==0, the 267 * match must be exact (ie, same as mask=-1ULL). 268 */ 269 int zap_value_search(objset_t *os, uint64_t zapobj, 270 uint64_t value, uint64_t mask, char *name); 271 272 /* 273 * Transfer all the entries from fromobj into intoobj. Only works on 274 * int_size=8 num_integers=1 values. Fails if there are any duplicated 275 * entries. 276 */ 277 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx); 278 279 /* 280 * Manipulate entries where the name + value are the "same" (the name is 281 * a stringified version of the value). 282 */ 283 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 284 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 285 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value); 286 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta, 287 dmu_tx_t *tx); 288 289 struct zap; 290 struct zap_leaf; 291 typedef struct zap_cursor { 292 /* This structure is opaque! */ 293 objset_t *zc_objset; 294 struct zap *zc_zap; 295 struct zap_leaf *zc_leaf; 296 uint64_t zc_zapobj; 297 uint64_t zc_serialized; 298 uint64_t zc_hash; 299 uint32_t zc_cd; 300 } zap_cursor_t; 301 302 typedef struct { 303 int za_integer_length; 304 /* 305 * za_normalization_conflict will be set if there are additional 306 * entries with this normalized form (eg, "foo" and "Foo"). 307 */ 308 boolean_t za_normalization_conflict; 309 uint64_t za_num_integers; 310 uint64_t za_first_integer; /* no sign extension for <8byte ints */ 311 char za_name[MAXNAMELEN]; 312 } zap_attribute_t; 313 314 /* 315 * The interface for listing all the attributes of a zapobj can be 316 * thought of as cursor moving down a list of the attributes one by 317 * one. The cookie returned by the zap_cursor_serialize routine is 318 * persistent across system calls (and across reboot, even). 319 */ 320 321 /* 322 * Initialize a zap cursor, pointing to the "first" attribute of the 323 * zapobj. You must _fini the cursor when you are done with it. 324 */ 325 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj); 326 void zap_cursor_fini(zap_cursor_t *zc); 327 328 /* 329 * Get the attribute currently pointed to by the cursor. Returns 330 * ENOENT if at the end of the attributes. 331 */ 332 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za); 333 334 /* 335 * Advance the cursor to the next attribute. 336 */ 337 void zap_cursor_advance(zap_cursor_t *zc); 338 339 /* 340 * Get a persistent cookie pointing to the current position of the zap 341 * cursor. The low 4 bits in the cookie are always zero, and thus can 342 * be used as to differentiate a serialized cookie from a different type 343 * of value. The cookie will be less than 2^32 as long as there are 344 * fewer than 2^22 (4.2 million) entries in the zap object. 345 */ 346 uint64_t zap_cursor_serialize(zap_cursor_t *zc); 347 348 /* 349 * Advance the cursor to the attribute having the given key. 350 */ 351 int zap_cursor_move_to_key(zap_cursor_t *zc, const char *name, matchtype_t mt); 352 353 /* 354 * Initialize a zap cursor pointing to the position recorded by 355 * zap_cursor_serialize (in the "serialized" argument). You can also 356 * use a "serialized" argument of 0 to start at the beginning of the 357 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to 358 * zap_cursor_init(...).) 359 */ 360 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds, 361 uint64_t zapobj, uint64_t serialized); 362 363 364 #define ZAP_HISTOGRAM_SIZE 10 365 366 typedef struct zap_stats { 367 /* 368 * Size of the pointer table (in number of entries). 369 * This is always a power of 2, or zero if it's a microzap. 370 * In general, it should be considerably greater than zs_num_leafs. 371 */ 372 uint64_t zs_ptrtbl_len; 373 374 uint64_t zs_blocksize; /* size of zap blocks */ 375 376 /* 377 * The number of blocks used. Note that some blocks may be 378 * wasted because old ptrtbl's and large name/value blocks are 379 * not reused. (Although their space is reclaimed, we don't 380 * reuse those offsets in the object.) 381 */ 382 uint64_t zs_num_blocks; 383 384 /* 385 * Pointer table values from zap_ptrtbl in the zap_phys_t 386 */ 387 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */ 388 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */ 389 uint64_t zs_ptrtbl_zt_blk; /* starting block number */ 390 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */ 391 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */ 392 393 /* 394 * Values of the other members of the zap_phys_t 395 */ 396 uint64_t zs_block_type; /* ZBT_HEADER */ 397 uint64_t zs_magic; /* ZAP_MAGIC */ 398 uint64_t zs_num_leafs; /* The number of leaf blocks */ 399 uint64_t zs_num_entries; /* The number of zap entries */ 400 uint64_t zs_salt; /* salt to stir into hash function */ 401 402 /* 403 * Histograms. For all histograms, the last index 404 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater 405 * than what can be represented. For example 406 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number 407 * of leafs with more than 45 entries. 408 */ 409 410 /* 411 * zs_leafs_with_n_pointers[n] is the number of leafs with 412 * 2^n pointers to it. 413 */ 414 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE]; 415 416 /* 417 * zs_leafs_with_n_entries[n] is the number of leafs with 418 * [n*5, (n+1)*5) entries. In the current implementation, there 419 * can be at most 55 entries in any block, but there may be 420 * fewer if the name or value is large, or the block is not 421 * completely full. 422 */ 423 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE]; 424 425 /* 426 * zs_leafs_n_tenths_full[n] is the number of leafs whose 427 * fullness is in the range [n/10, (n+1)/10). 428 */ 429 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE]; 430 431 /* 432 * zs_entries_using_n_chunks[n] is the number of entries which 433 * consume n 24-byte chunks. (Note, large names/values only use 434 * one chunk, but contribute to zs_num_blocks_large.) 435 */ 436 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE]; 437 438 /* 439 * zs_buckets_with_n_entries[n] is the number of buckets (each 440 * leaf has 64 buckets) with n entries. 441 * zs_buckets_with_n_entries[1] should be very close to 442 * zs_num_entries. 443 */ 444 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE]; 445 } zap_stats_t; 446 447 /* 448 * Get statistics about a ZAP object. Note: you need to be aware of the 449 * internal implementation of the ZAP to correctly interpret some of the 450 * statistics. This interface shouldn't be relied on unless you really 451 * know what you're doing. 452 */ 453 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs); 454 455 #ifdef __cplusplus 456 } 457 #endif 458 459 #endif /* _SYS_ZAP_H */ 460