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