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 2007 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 #pragma ident "%Z%%M% %I% %E% SMI" 30 31 /* 32 * ZAP - ZFS Attribute Processor 33 * 34 * The ZAP is a module which sits on top of the DMU (Data Management 35 * Unit) and implements a higher-level storage primitive using DMU 36 * objects. Its primary consumer is the ZPL (ZFS Posix Layer). 37 * 38 * A "zapobj" is a DMU object which the ZAP uses to stores attributes. 39 * Users should use only zap routines to access a zapobj - they should 40 * not access the DMU object directly using DMU routines. 41 * 42 * The attributes stored in a zapobj are name-value pairs. The name is 43 * a zero-terminated string of up to ZAP_MAXNAMELEN bytes (including 44 * terminating NULL). The value is an array of integers, which may be 45 * 1, 2, 4, or 8 bytes long. The total space used by the array (number 46 * of integers * integer length) can be up to ZAP_MAXVALUELEN bytes. 47 * Note that an 8-byte integer value can be used to store the location 48 * (object number) of another dmu object (which may be itself a zapobj). 49 * Note that you can use a zero-length attribute to store a single bit 50 * of information - the attribute is present or not. 51 * 52 * The ZAP routines are thread-safe. However, you must observe the 53 * DMU's restriction that a transaction may not be operated on 54 * concurrently. 55 * 56 * Any of the routines that return an int may return an I/O error (EIO 57 * or ECHECKSUM). 58 * 59 * 60 * Implementation / Performance Notes: 61 * 62 * The ZAP is intended to operate most efficiently on attributes with 63 * short (49 bytes or less) names and single 8-byte values, for which 64 * the microzap will be used. The ZAP should be efficient enough so 65 * that the user does not need to cache these attributes. 66 * 67 * The ZAP's locking scheme makes its routines thread-safe. Operations 68 * on different zapobjs will be processed concurrently. Operations on 69 * the same zapobj which only read data will be processed concurrently. 70 * Operations on the same zapobj which modify data will be processed 71 * concurrently when there are many attributes in the zapobj (because 72 * the ZAP uses per-block locking - more than 128 * (number of cpus) 73 * small attributes will suffice). 74 */ 75 76 /* 77 * We're using zero-terminated byte strings (ie. ASCII or UTF-8 C 78 * strings) for the names of attributes, rather than a byte string 79 * bounded by an explicit length. If some day we want to support names 80 * in character sets which have embedded zeros (eg. UTF-16, UTF-32), 81 * we'll have to add routines for using length-bounded strings. 82 */ 83 84 #include <sys/dmu.h> 85 86 #ifdef __cplusplus 87 extern "C" { 88 #endif 89 90 #define ZAP_MAXNAMELEN 256 91 #define ZAP_MAXVALUELEN 1024 92 93 /* 94 * The matchtype specifies which entry will be accessed. 95 * MT_EXACT: only find an exact match (non-normalized) 96 * MT_FIRST: find the "first" normalized (case and Unicode 97 * form) match; the designated "first" match will not change as long 98 * as the set of entries with this normalization doesn't change 99 * MT_BEST: if there is an exact match, find that, otherwise find the 100 * first normalized match 101 */ 102 typedef enum matchtype 103 { 104 MT_EXACT, 105 MT_BEST, 106 MT_FIRST 107 } matchtype_t; 108 109 /* 110 * Create a new zapobj with no attributes and return its object number. 111 * MT_EXACT will cause the zap object to only support MT_EXACT lookups, 112 * otherwise any matchtype can be used for lookups. 113 * 114 * normflags specifies what normalization will be done. values are: 115 * 0: no normalization (legacy on-disk format, supports MT_EXACT matching 116 * only) 117 * U8_TEXTPREP_TOLOWER: case normalization will be performed. 118 * MT_FIRST/MT_BEST matching will find entries that match without 119 * regard to case (eg. looking for "foo" can find an entry "Foo"). 120 * Eventually, other flags will permit unicode normalization as well. 121 */ 122 uint64_t zap_create(objset_t *ds, dmu_object_type_t ot, 123 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 124 uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot, 125 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 126 127 /* 128 * Create a new zapobj with no attributes from the given (unallocated) 129 * object number. 130 */ 131 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot, 132 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 133 int zap_create_claim_norm(objset_t *ds, uint64_t obj, 134 int normflags, dmu_object_type_t ot, 135 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx); 136 137 /* 138 * The zapobj passed in must be a valid ZAP object for all of the 139 * following routines. 140 */ 141 142 /* 143 * Destroy this zapobj and all its attributes. 144 * 145 * Frees the object number using dmu_object_free. 146 */ 147 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx); 148 149 /* 150 * Manipulate attributes. 151 * 152 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8. 153 */ 154 155 /* 156 * Retrieve the contents of the attribute with the given name. 157 * 158 * If the requested attribute does not exist, the call will fail and 159 * return ENOENT. 160 * 161 * If 'integer_size' is smaller than the attribute's integer size, the 162 * call will fail and return EINVAL. 163 * 164 * If 'integer_size' is equal to or larger than the attribute's integer 165 * size, the call will succeed and return 0. * When converting to a 166 * larger integer size, the integers will be treated as unsigned (ie. no 167 * sign-extension will be performed). 168 * 169 * 'num_integers' is the length (in integers) of 'buf'. 170 * 171 * If the attribute is longer than the buffer, as many integers as will 172 * fit will be transferred to 'buf'. If the entire attribute was not 173 * transferred, the call will return EOVERFLOW. 174 * 175 * If rn_len is nonzero, realname will be set to the name of the found 176 * entry (which may be different from the requested name if matchtype is 177 * not MT_EXACT). 178 * 179 * If normalization_conflictp is not NULL, it will be set if there is 180 * another name with the same case/unicode normalized form. 181 */ 182 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name, 183 uint64_t integer_size, uint64_t num_integers, void *buf); 184 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name, 185 uint64_t integer_size, uint64_t num_integers, void *buf, 186 matchtype_t mt, char *realname, int rn_len, 187 boolean_t *normalization_conflictp); 188 189 /* 190 * Create an attribute with the given name and value. 191 * 192 * If an attribute with the given name already exists, the call will 193 * fail and return EEXIST. 194 */ 195 int zap_add(objset_t *ds, uint64_t zapobj, const char *name, 196 int integer_size, uint64_t num_integers, 197 const void *val, dmu_tx_t *tx); 198 199 /* 200 * Set the attribute with the given name to the given value. If an 201 * attribute with the given name does not exist, it will be created. If 202 * an attribute with the given name already exists, the previous value 203 * will be overwritten. The integer_size may be different from the 204 * existing attribute's integer size, in which case the attribute's 205 * integer size will be updated to the new value. 206 */ 207 int zap_update(objset_t *ds, uint64_t zapobj, const char *name, 208 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx); 209 210 /* 211 * Get the length (in integers) and the integer size of the specified 212 * attribute. 213 * 214 * If the requested attribute does not exist, the call will fail and 215 * return ENOENT. 216 */ 217 int zap_length(objset_t *ds, uint64_t zapobj, const char *name, 218 uint64_t *integer_size, uint64_t *num_integers); 219 220 /* 221 * Remove the specified attribute. 222 * 223 * If the specified attribute does not exist, the call will fail and 224 * return ENOENT. 225 */ 226 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx); 227 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name, 228 matchtype_t mt, dmu_tx_t *tx); 229 230 /* 231 * Returns (in *count) the number of attributes in the specified zap 232 * object. 233 */ 234 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count); 235 236 237 /* 238 * Returns (in name) the name of the entry whose (value & mask) 239 * (za_first_integer) is value, or ENOENT if not found. The string 240 * pointed to by name must be at least 256 bytes long. If mask==0, the 241 * match must be exact (ie, same as mask=-1ULL). 242 */ 243 int zap_value_search(objset_t *os, uint64_t zapobj, 244 uint64_t value, uint64_t mask, char *name); 245 246 struct zap; 247 struct zap_leaf; 248 typedef struct zap_cursor { 249 /* This structure is opaque! */ 250 objset_t *zc_objset; 251 struct zap *zc_zap; 252 struct zap_leaf *zc_leaf; 253 uint64_t zc_zapobj; 254 uint64_t zc_hash; 255 uint32_t zc_cd; 256 } zap_cursor_t; 257 258 typedef struct { 259 int za_integer_length; 260 /* 261 * za_normalization_conflict will be set if there are additional 262 * entries with this normalized form (eg, "foo" and "Foo"). 263 */ 264 boolean_t za_normalization_conflict; 265 uint64_t za_num_integers; 266 uint64_t za_first_integer; /* no sign extension for <8byte ints */ 267 char za_name[MAXNAMELEN]; 268 } zap_attribute_t; 269 270 /* 271 * The interface for listing all the attributes of a zapobj can be 272 * thought of as cursor moving down a list of the attributes one by 273 * one. The cookie returned by the zap_cursor_serialize routine is 274 * persistent across system calls (and across reboot, even). 275 */ 276 277 /* 278 * Initialize a zap cursor, pointing to the "first" attribute of the 279 * zapobj. You must _fini the cursor when you are done with it. 280 */ 281 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj); 282 void zap_cursor_fini(zap_cursor_t *zc); 283 284 /* 285 * Get the attribute currently pointed to by the cursor. Returns 286 * ENOENT if at the end of the attributes. 287 */ 288 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za); 289 290 /* 291 * Advance the cursor to the next attribute. 292 */ 293 void zap_cursor_advance(zap_cursor_t *zc); 294 295 /* 296 * Get a persistent cookie pointing to the current position of the zap 297 * cursor. The low 4 bits in the cookie are always zero, and thus can 298 * be used as to differentiate a serialized cookie from a different type 299 * of value. The cookie will be less than 2^32 as long as there are 300 * fewer than 2^22 (4.2 million) entries in the zap object. 301 */ 302 uint64_t zap_cursor_serialize(zap_cursor_t *zc); 303 304 /* 305 * Initialize a zap cursor pointing to the position recorded by 306 * zap_cursor_serialize (in the "serialized" argument). You can also 307 * use a "serialized" argument of 0 to start at the beginning of the 308 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to 309 * zap_cursor_init(...).) 310 */ 311 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds, 312 uint64_t zapobj, uint64_t serialized); 313 314 315 #define ZAP_HISTOGRAM_SIZE 10 316 317 typedef struct zap_stats { 318 /* 319 * Size of the pointer table (in number of entries). 320 * This is always a power of 2, or zero if it's a microzap. 321 * In general, it should be considerably greater than zs_num_leafs. 322 */ 323 uint64_t zs_ptrtbl_len; 324 325 uint64_t zs_blocksize; /* size of zap blocks */ 326 327 /* 328 * The number of blocks used. Note that some blocks may be 329 * wasted because old ptrtbl's and large name/value blocks are 330 * not reused. (Although their space is reclaimed, we don't 331 * reuse those offsets in the object.) 332 */ 333 uint64_t zs_num_blocks; 334 335 /* 336 * Pointer table values from zap_ptrtbl in the zap_phys_t 337 */ 338 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */ 339 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */ 340 uint64_t zs_ptrtbl_zt_blk; /* starting block number */ 341 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */ 342 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */ 343 344 /* 345 * Values of the other members of the zap_phys_t 346 */ 347 uint64_t zs_block_type; /* ZBT_HEADER */ 348 uint64_t zs_magic; /* ZAP_MAGIC */ 349 uint64_t zs_num_leafs; /* The number of leaf blocks */ 350 uint64_t zs_num_entries; /* The number of zap entries */ 351 uint64_t zs_salt; /* salt to stir into hash function */ 352 353 /* 354 * Histograms. For all histograms, the last index 355 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater 356 * than what can be represented. For example 357 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number 358 * of leafs with more than 45 entries. 359 */ 360 361 /* 362 * zs_leafs_with_n_pointers[n] is the number of leafs with 363 * 2^n pointers to it. 364 */ 365 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE]; 366 367 /* 368 * zs_leafs_with_n_entries[n] is the number of leafs with 369 * [n*5, (n+1)*5) entries. In the current implementation, there 370 * can be at most 55 entries in any block, but there may be 371 * fewer if the name or value is large, or the block is not 372 * completely full. 373 */ 374 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE]; 375 376 /* 377 * zs_leafs_n_tenths_full[n] is the number of leafs whose 378 * fullness is in the range [n/10, (n+1)/10). 379 */ 380 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE]; 381 382 /* 383 * zs_entries_using_n_chunks[n] is the number of entries which 384 * consume n 24-byte chunks. (Note, large names/values only use 385 * one chunk, but contribute to zs_num_blocks_large.) 386 */ 387 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE]; 388 389 /* 390 * zs_buckets_with_n_entries[n] is the number of buckets (each 391 * leaf has 64 buckets) with n entries. 392 * zs_buckets_with_n_entries[1] should be very close to 393 * zs_num_entries. 394 */ 395 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE]; 396 } zap_stats_t; 397 398 /* 399 * Get statistics about a ZAP object. Note: you need to be aware of the 400 * internal implementation of the ZAP to correctly interpret some of the 401 * statistics. This interface shouldn't be relied on unless you really 402 * know what you're doing. 403 */ 404 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs); 405 406 #ifdef __cplusplus 407 } 408 #endif 409 410 #endif /* _SYS_ZAP_H */ 411