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