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 int zap_count_write(objset_t *os, uint64_t zapobj, const char *name, 185 int add, uint64_t *towrite, uint64_t *tooverwrite); 186 187 /* 188 * Create an attribute with the given name and value. 189 * 190 * If an attribute with the given name already exists, the call will 191 * fail and return EEXIST. 192 */ 193 int zap_add(objset_t *ds, uint64_t zapobj, const char *name, 194 int integer_size, uint64_t num_integers, 195 const void *val, dmu_tx_t *tx); 196 197 /* 198 * Set the attribute with the given name to the given value. If an 199 * attribute with the given name does not exist, it will be created. If 200 * an attribute with the given name already exists, the previous value 201 * will be overwritten. The integer_size may be different from the 202 * existing attribute's integer size, in which case the attribute's 203 * integer size will be updated to the new value. 204 */ 205 int zap_update(objset_t *ds, uint64_t zapobj, const char *name, 206 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 207 208 /* 209 * Get the length (in integers) and the integer size of the specified 210 * attribute. 211 * 212 * If the requested attribute does not exist, the call will fail and 213 * return ENOENT. 214 */ 215 int zap_length(objset_t *ds, uint64_t zapobj, const char *name, 216 uint64_t *integer_size, uint64_t *num_integers); 217 218 /* 219 * Remove the specified attribute. 220 * 221 * If the specified attribute does not exist, the call will fail and 222 * return ENOENT. 223 */ 224 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx); 225 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name, 226 matchtype_t mt, dmu_tx_t *tx); 227 228 /* 229 * Returns (in *count) the number of attributes in the specified zap 230 * object. 231 */ 232 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count); 233 234 235 /* 236 * Returns (in name) the name of the entry whose (value & mask) 237 * (za_first_integer) is value, or ENOENT if not found. The string 238 * pointed to by name must be at least 256 bytes long. If mask==0, the 239 * match must be exact (ie, same as mask=-1ULL). 240 */ 241 int zap_value_search(objset_t *os, uint64_t zapobj, 242 uint64_t value, uint64_t mask, char *name); 243 244 /* 245 * Transfer all the entries from fromobj into intoobj. Only works on 246 * int_size=8 num_integers=1 values. Fails if there are any duplicated 247 * entries. 248 */ 249 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx); 250 251 /* 252 * Manipulate entries where the name + value are the "same" (the name is 253 * a stringified version of the value). 254 */ 255 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 256 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx); 257 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value); 258 259 struct zap; 260 struct zap_leaf; 261 typedef struct zap_cursor { 262 /* This structure is opaque! */ 263 objset_t *zc_objset; 264 struct zap *zc_zap; 265 struct zap_leaf *zc_leaf; 266 uint64_t zc_zapobj; 267 uint64_t zc_hash; 268 uint32_t zc_cd; 269 } zap_cursor_t; 270 271 typedef struct { 272 int za_integer_length; 273 /* 274 * za_normalization_conflict will be set if there are additional 275 * entries with this normalized form (eg, "foo" and "Foo"). 276 */ 277 boolean_t za_normalization_conflict; 278 uint64_t za_num_integers; 279 uint64_t za_first_integer; /* no sign extension for <8byte ints */ 280 char za_name[MAXNAMELEN]; 281 } zap_attribute_t; 282 283 /* 284 * The interface for listing all the attributes of a zapobj can be 285 * thought of as cursor moving down a list of the attributes one by 286 * one. The cookie returned by the zap_cursor_serialize routine is 287 * persistent across system calls (and across reboot, even). 288 */ 289 290 /* 291 * Initialize a zap cursor, pointing to the "first" attribute of the 292 * zapobj. You must _fini the cursor when you are done with it. 293 */ 294 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj); 295 void zap_cursor_fini(zap_cursor_t *zc); 296 297 /* 298 * Get the attribute currently pointed to by the cursor. Returns 299 * ENOENT if at the end of the attributes. 300 */ 301 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za); 302 303 /* 304 * Advance the cursor to the next attribute. 305 */ 306 void zap_cursor_advance(zap_cursor_t *zc); 307 308 /* 309 * Get a persistent cookie pointing to the current position of the zap 310 * cursor. The low 4 bits in the cookie are always zero, and thus can 311 * be used as to differentiate a serialized cookie from a different type 312 * of value. The cookie will be less than 2^32 as long as there are 313 * fewer than 2^22 (4.2 million) entries in the zap object. 314 */ 315 uint64_t zap_cursor_serialize(zap_cursor_t *zc); 316 317 /* 318 * Initialize a zap cursor pointing to the position recorded by 319 * zap_cursor_serialize (in the "serialized" argument). You can also 320 * use a "serialized" argument of 0 to start at the beginning of the 321 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to 322 * zap_cursor_init(...).) 323 */ 324 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds, 325 uint64_t zapobj, uint64_t serialized); 326 327 328 #define ZAP_HISTOGRAM_SIZE 10 329 330 typedef struct zap_stats { 331 /* 332 * Size of the pointer table (in number of entries). 333 * This is always a power of 2, or zero if it's a microzap. 334 * In general, it should be considerably greater than zs_num_leafs. 335 */ 336 uint64_t zs_ptrtbl_len; 337 338 uint64_t zs_blocksize; /* size of zap blocks */ 339 340 /* 341 * The number of blocks used. Note that some blocks may be 342 * wasted because old ptrtbl's and large name/value blocks are 343 * not reused. (Although their space is reclaimed, we don't 344 * reuse those offsets in the object.) 345 */ 346 uint64_t zs_num_blocks; 347 348 /* 349 * Pointer table values from zap_ptrtbl in the zap_phys_t 350 */ 351 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */ 352 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */ 353 uint64_t zs_ptrtbl_zt_blk; /* starting block number */ 354 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */ 355 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */ 356 357 /* 358 * Values of the other members of the zap_phys_t 359 */ 360 uint64_t zs_block_type; /* ZBT_HEADER */ 361 uint64_t zs_magic; /* ZAP_MAGIC */ 362 uint64_t zs_num_leafs; /* The number of leaf blocks */ 363 uint64_t zs_num_entries; /* The number of zap entries */ 364 uint64_t zs_salt; /* salt to stir into hash function */ 365 366 /* 367 * Histograms. For all histograms, the last index 368 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater 369 * than what can be represented. For example 370 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number 371 * of leafs with more than 45 entries. 372 */ 373 374 /* 375 * zs_leafs_with_n_pointers[n] is the number of leafs with 376 * 2^n pointers to it. 377 */ 378 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE]; 379 380 /* 381 * zs_leafs_with_n_entries[n] is the number of leafs with 382 * [n*5, (n+1)*5) entries. In the current implementation, there 383 * can be at most 55 entries in any block, but there may be 384 * fewer if the name or value is large, or the block is not 385 * completely full. 386 */ 387 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE]; 388 389 /* 390 * zs_leafs_n_tenths_full[n] is the number of leafs whose 391 * fullness is in the range [n/10, (n+1)/10). 392 */ 393 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE]; 394 395 /* 396 * zs_entries_using_n_chunks[n] is the number of entries which 397 * consume n 24-byte chunks. (Note, large names/values only use 398 * one chunk, but contribute to zs_num_blocks_large.) 399 */ 400 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE]; 401 402 /* 403 * zs_buckets_with_n_entries[n] is the number of buckets (each 404 * leaf has 64 buckets) with n entries. 405 * zs_buckets_with_n_entries[1] should be very close to 406 * zs_num_entries. 407 */ 408 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE]; 409 } zap_stats_t; 410 411 /* 412 * Get statistics about a ZAP object. Note: you need to be aware of the 413 * internal implementation of the ZAP to correctly interpret some of the 414 * statistics. This interface shouldn't be relied on unless you really 415 * know what you're doing. 416 */ 417 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs); 418 419 #ifdef __cplusplus 420 } 421 #endif 422 423 #endif /* _SYS_ZAP_H */ 424