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) 2013 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  * Specifies matching criteria for ZAP lookups.
  90  */
  91 typedef enum matchtype
  92 {
  93         /* Only find an exact match (non-normalized) */
  94         MT_EXACT,
  95         /*
  96          * If there is an exact match, find that, otherwise find the
  97          * first normalized match.
  98          */
  99         MT_BEST,
 100         /*
 101          * Find the "first" normalized (case and Unicode form) match;
 102          * the designated "first" match will not change as long as the
 103          * set of entries with this normalization doesn't change.
 104          */
 105         MT_FIRST
 106 } matchtype_t;
 107 
 108 typedef enum zap_flags {
 109         /* Use 64-bit hash value (serialized cursors will always use 64-bits) */
 110         ZAP_FLAG_HASH64 = 1 << 0,
 111         /* Key is binary, not string (zap_add_uint64() can be used) */
 112         ZAP_FLAG_UINT64_KEY = 1 << 1,
 113         /*
 114          * First word of key (which must be an array of uint64) is
 115          * already randomly distributed.
 116          */
 117         ZAP_FLAG_PRE_HASHED_KEY = 1 << 2,
 118 } zap_flags_t;
 119 
 120 /*
 121  * Create a new zapobj with no attributes and return its object number.
 122  * MT_EXACT will cause the zap object to only support MT_EXACT lookups,
 123  * otherwise any matchtype can be used for lookups.
 124  *
 125  * normflags specifies what normalization will be done.  values are:
 126  * 0: no normalization (legacy on-disk format, supports MT_EXACT matching
 127  *     only)
 128  * U8_TEXTPREP_TOLOWER: case normalization will be performed.
 129  *     MT_FIRST/MT_BEST matching will find entries that match without
 130  *     regard to case (eg. looking for "foo" can find an entry "Foo").
 131  * Eventually, other flags will permit unicode normalization as well.
 132  */
 133 uint64_t zap_create(objset_t *ds, dmu_object_type_t ot,
 134     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
 135 uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot,
 136     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
 137 uint64_t zap_create_flags(objset_t *os, int normflags, zap_flags_t flags,
 138     dmu_object_type_t ot, int leaf_blockshift, int indirect_blockshift,
 139     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
 140 uint64_t zap_create_link(objset_t *os, dmu_object_type_t ot,
 141     uint64_t parent_obj, const char *name, dmu_tx_t *tx);
 142 
 143 /*
 144  * Create a new zapobj with no attributes from the given (unallocated)
 145  * object number.
 146  */
 147 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot,
 148     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
 149 int zap_create_claim_norm(objset_t *ds, uint64_t obj,
 150     int normflags, dmu_object_type_t ot,
 151     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
 152 
 153 /*
 154  * The zapobj passed in must be a valid ZAP object for all of the
 155  * following routines.
 156  */
 157 
 158 /*
 159  * Destroy this zapobj and all its attributes.
 160  *
 161  * Frees the object number using dmu_object_free.
 162  */
 163 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx);
 164 
 165 /*
 166  * Manipulate attributes.
 167  *
 168  * 'integer_size' is in bytes, and must be 1, 2, 4, or 8.
 169  */
 170 
 171 /*
 172  * Retrieve the contents of the attribute with the given name.
 173  *
 174  * If the requested attribute does not exist, the call will fail and
 175  * return ENOENT.
 176  *
 177  * If 'integer_size' is smaller than the attribute's integer size, the
 178  * call will fail and return EINVAL.
 179  *
 180  * If 'integer_size' is equal to or larger than the attribute's integer
 181  * size, the call will succeed and return 0.
 182  *
 183  * When converting to a larger integer size, the integers will be treated as
 184  * unsigned (ie. no sign-extension will be performed).
 185  *
 186  * 'num_integers' is the length (in integers) of 'buf'.
 187  *
 188  * If the attribute is longer than the buffer, as many integers as will
 189  * fit will be transferred to 'buf'.  If the entire attribute was not
 190  * transferred, the call will return EOVERFLOW.
 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 
 195 /*
 196  * If rn_len is nonzero, realname will be set to the name of the found
 197  * entry (which may be different from the requested name if matchtype is
 198  * not MT_EXACT).
 199  *
 200  * If normalization_conflictp is not NULL, it will be set if there is
 201  * another name with the same case/unicode normalized form.
 202  */
 203 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name,
 204     uint64_t integer_size, uint64_t num_integers, void *buf,
 205     matchtype_t mt, char *realname, int rn_len,
 206     boolean_t *normalization_conflictp);
 207 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
 208     int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf);
 209 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name);
 210 int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
 211     int key_numints);
 212 
 213 int zap_count_write(objset_t *os, uint64_t zapobj, const char *name,
 214     int add, uint64_t *towrite, uint64_t *tooverwrite);
 215 
 216 /*
 217  * Create an attribute with the given name and value.
 218  *
 219  * If an attribute with the given name already exists, the call will
 220  * fail and return EEXIST.
 221  */
 222 int zap_add(objset_t *ds, uint64_t zapobj, const char *key,
 223     int integer_size, uint64_t num_integers,
 224     const void *val, dmu_tx_t *tx);
 225 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key,
 226     int key_numints, int integer_size, uint64_t num_integers,
 227     const void *val, dmu_tx_t *tx);
 228 
 229 /*
 230  * Set the attribute with the given name to the given value.  If an
 231  * attribute with the given name does not exist, it will be created.  If
 232  * an attribute with the given name already exists, the previous value
 233  * will be overwritten.  The integer_size may be different from the
 234  * existing attribute's integer size, in which case the attribute's
 235  * integer size will be updated to the new value.
 236  */
 237 int zap_update(objset_t *ds, uint64_t zapobj, const char *name,
 238     int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
 239 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
 240     int key_numints,
 241     int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
 242 
 243 /*
 244  * Get the length (in integers) and the integer size of the specified
 245  * attribute.
 246  *
 247  * If the requested attribute does not exist, the call will fail and
 248  * return ENOENT.
 249  */
 250 int zap_length(objset_t *ds, uint64_t zapobj, const char *name,
 251     uint64_t *integer_size, uint64_t *num_integers);
 252 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
 253     int key_numints, uint64_t *integer_size, uint64_t *num_integers);
 254 
 255 /*
 256  * Remove the specified attribute.
 257  *
 258  * If the specified attribute does not exist, the call will fail and
 259  * return ENOENT.
 260  */
 261 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx);
 262 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name,
 263     matchtype_t mt, dmu_tx_t *tx);
 264 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
 265     int key_numints, dmu_tx_t *tx);
 266 
 267 /*
 268  * Returns (in *count) the number of attributes in the specified zap
 269  * object.
 270  */
 271 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count);
 272 
 273 /*
 274  * Returns (in name) the name of the entry whose (value & mask)
 275  * (za_first_integer) is value, or ENOENT if not found.  The string
 276  * pointed to by name must be at least 256 bytes long.  If mask==0, the
 277  * match must be exact (ie, same as mask=-1ULL).
 278  */
 279 int zap_value_search(objset_t *os, uint64_t zapobj,
 280     uint64_t value, uint64_t mask, char *name);
 281 
 282 /*
 283  * Transfer all the entries from fromobj into intoobj.  Only works on
 284  * int_size=8 num_integers=1 values.  Fails if there are any duplicated
 285  * entries.
 286  */
 287 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx);
 288 
 289 /* Same as zap_join, but set the values to 'value'. */
 290 int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
 291     uint64_t value, dmu_tx_t *tx);
 292 
 293 /* Same as zap_join, but add together any duplicated entries. */
 294 int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
 295     dmu_tx_t *tx);
 296 
 297 /*
 298  * Manipulate entries where the name + value are the "same" (the name is
 299  * a stringified version of the value).
 300  */
 301 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
 302 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
 303 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value);
 304 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
 305     dmu_tx_t *tx);
 306 
 307 /* Here the key is an int and the value is a different int. */
 308 int zap_add_int_key(objset_t *os, uint64_t obj,
 309     uint64_t key, uint64_t value, dmu_tx_t *tx);
 310 int zap_update_int_key(objset_t *os, uint64_t obj,
 311     uint64_t key, uint64_t value, dmu_tx_t *tx);
 312 int zap_lookup_int_key(objset_t *os, uint64_t obj,
 313     uint64_t key, uint64_t *valuep);
 314 
 315 int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,
 316     dmu_tx_t *tx);
 317 
 318 struct zap;
 319 struct zap_leaf;
 320 typedef struct zap_cursor {
 321         /* This structure is opaque! */
 322         objset_t *zc_objset;
 323         struct zap *zc_zap;
 324         struct zap_leaf *zc_leaf;
 325         uint64_t zc_zapobj;
 326         uint64_t zc_serialized;
 327         uint64_t zc_hash;
 328         uint32_t zc_cd;
 329 } zap_cursor_t;
 330 
 331 typedef struct {
 332         int za_integer_length;
 333         /*
 334          * za_normalization_conflict will be set if there are additional
 335          * entries with this normalized form (eg, "foo" and "Foo").
 336          */
 337         boolean_t za_normalization_conflict;
 338         uint64_t za_num_integers;
 339         uint64_t za_first_integer;      /* no sign extension for <8byte ints */
 340         char za_name[MAXNAMELEN];
 341 } zap_attribute_t;
 342 
 343 /*
 344  * The interface for listing all the attributes of a zapobj can be
 345  * thought of as cursor moving down a list of the attributes one by
 346  * one.  The cookie returned by the zap_cursor_serialize routine is
 347  * persistent across system calls (and across reboot, even).
 348  */
 349 
 350 /*
 351  * Initialize a zap cursor, pointing to the "first" attribute of the
 352  * zapobj.  You must _fini the cursor when you are done with it.
 353  */
 354 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj);
 355 void zap_cursor_fini(zap_cursor_t *zc);
 356 
 357 /*
 358  * Get the attribute currently pointed to by the cursor.  Returns
 359  * ENOENT if at the end of the attributes.
 360  */
 361 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za);
 362 
 363 /*
 364  * Advance the cursor to the next attribute.
 365  */
 366 void zap_cursor_advance(zap_cursor_t *zc);
 367 
 368 /*
 369  * Get a persistent cookie pointing to the current position of the zap
 370  * cursor.  The low 4 bits in the cookie are always zero, and thus can
 371  * be used as to differentiate a serialized cookie from a different type
 372  * of value.  The cookie will be less than 2^32 as long as there are
 373  * fewer than 2^22 (4.2 million) entries in the zap object.
 374  */
 375 uint64_t zap_cursor_serialize(zap_cursor_t *zc);
 376 
 377 /*
 378  * Initialize a zap cursor pointing to the position recorded by
 379  * zap_cursor_serialize (in the "serialized" argument).  You can also
 380  * use a "serialized" argument of 0 to start at the beginning of the
 381  * zapobj (ie.  zap_cursor_init_serialized(..., 0) is equivalent to
 382  * zap_cursor_init(...).)
 383  */
 384 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds,
 385     uint64_t zapobj, uint64_t serialized);
 386 
 387 
 388 #define ZAP_HISTOGRAM_SIZE 10
 389 
 390 typedef struct zap_stats {
 391         /*
 392          * Size of the pointer table (in number of entries).
 393          * This is always a power of 2, or zero if it's a microzap.
 394          * In general, it should be considerably greater than zs_num_leafs.
 395          */
 396         uint64_t zs_ptrtbl_len;
 397 
 398         uint64_t zs_blocksize;          /* size of zap blocks */
 399 
 400         /*
 401          * The number of blocks used.  Note that some blocks may be
 402          * wasted because old ptrtbl's and large name/value blocks are
 403          * not reused.  (Although their space is reclaimed, we don't
 404          * reuse those offsets in the object.)
 405          */
 406         uint64_t zs_num_blocks;
 407 
 408         /*
 409          * Pointer table values from zap_ptrtbl in the zap_phys_t
 410          */
 411         uint64_t zs_ptrtbl_nextblk;       /* next (larger) copy start block */
 412         uint64_t zs_ptrtbl_blks_copied;   /* number source blocks copied */
 413         uint64_t zs_ptrtbl_zt_blk;        /* starting block number */
 414         uint64_t zs_ptrtbl_zt_numblks;    /* number of blocks */
 415         uint64_t zs_ptrtbl_zt_shift;      /* bits to index it */
 416 
 417         /*
 418          * Values of the other members of the zap_phys_t
 419          */
 420         uint64_t zs_block_type;         /* ZBT_HEADER */
 421         uint64_t zs_magic;              /* ZAP_MAGIC */
 422         uint64_t zs_num_leafs;          /* The number of leaf blocks */
 423         uint64_t zs_num_entries;        /* The number of zap entries */
 424         uint64_t zs_salt;               /* salt to stir into hash function */
 425 
 426         /*
 427          * Histograms.  For all histograms, the last index
 428          * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater
 429          * than what can be represented.  For example
 430          * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number
 431          * of leafs with more than 45 entries.
 432          */
 433 
 434         /*
 435          * zs_leafs_with_n_pointers[n] is the number of leafs with
 436          * 2^n pointers to it.
 437          */
 438         uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE];
 439 
 440         /*
 441          * zs_leafs_with_n_entries[n] is the number of leafs with
 442          * [n*5, (n+1)*5) entries.  In the current implementation, there
 443          * can be at most 55 entries in any block, but there may be
 444          * fewer if the name or value is large, or the block is not
 445          * completely full.
 446          */
 447         uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE];
 448 
 449         /*
 450          * zs_leafs_n_tenths_full[n] is the number of leafs whose
 451          * fullness is in the range [n/10, (n+1)/10).
 452          */
 453         uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE];
 454 
 455         /*
 456          * zs_entries_using_n_chunks[n] is the number of entries which
 457          * consume n 24-byte chunks.  (Note, large names/values only use
 458          * one chunk, but contribute to zs_num_blocks_large.)
 459          */
 460         uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE];
 461 
 462         /*
 463          * zs_buckets_with_n_entries[n] is the number of buckets (each
 464          * leaf has 64 buckets) with n entries.
 465          * zs_buckets_with_n_entries[1] should be very close to
 466          * zs_num_entries.
 467          */
 468         uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE];
 469 } zap_stats_t;
 470 
 471 /*
 472  * Get statistics about a ZAP object.  Note: you need to be aware of the
 473  * internal implementation of the ZAP to correctly interpret some of the
 474  * statistics.  This interface shouldn't be relied on unless you really
 475  * know what you're doing.
 476  */
 477 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs);
 478 
 479 #ifdef  __cplusplus
 480 }
 481 #endif
 482 
 483 #endif  /* _SYS_ZAP_H */