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 */
24
25 #ifndef _SYS_ZAP_H
26 #define _SYS_ZAP_H
27
28 /*
29 * ZAP - ZFS Attribute Processor
30 *
31 * The ZAP is a module which sits on top of the DMU (Data Management
32 * Unit) and implements a higher-level storage primitive using DMU
33 * objects. Its primary consumer is the ZPL (ZFS Posix Layer).
34 *
35 * A "zapobj" is a DMU object which the ZAP uses to stores attributes.
36 * Users should use only zap routines to access a zapobj - they should
37 * not access the DMU object directly using DMU routines.
38 *
39 * The attributes stored in a zapobj are name-value pairs. The name is
40 * a zero-terminated string of up to ZAP_MAXNAMELEN bytes (including
41 * terminating NULL). The value is an array of integers, which may be
42 * 1, 2, 4, or 8 bytes long. The total space used by the array (number
43 * of integers * integer length) can be up to ZAP_MAXVALUELEN bytes.
44 * Note that an 8-byte integer value can be used to store the location
45 * (object number) of another dmu object (which may be itself a zapobj).
46 * Note that you can use a zero-length attribute to store a single bit
47 * of information - the attribute is present or not.
48 *
49 * The ZAP routines are thread-safe. However, you must observe the
50 * DMU's restriction that a transaction may not be operated on
51 * concurrently.
52 *
53 * Any of the routines that return an int may return an I/O error (EIO
54 * or ECHECKSUM).
55 *
56 *
57 * Implementation / Performance Notes:
58 *
59 * The ZAP is intended to operate most efficiently on attributes with
60 * short (49 bytes or less) names and single 8-byte values, for which
61 * the microzap will be used. The ZAP should be efficient enough so
62 * that the user does not need to cache these attributes.
63 *
64 * The ZAP's locking scheme makes its routines thread-safe. Operations
65 * on different zapobjs will be processed concurrently. Operations on
66 * the same zapobj which only read data will be processed concurrently.
67 * Operations on the same zapobj which modify data will be processed
68 * concurrently when there are many attributes in the zapobj (because
69 * the ZAP uses per-block locking - more than 128 * (number of cpus)
70 * small attributes will suffice).
71 */
72
73 /*
74 * We're using zero-terminated byte strings (ie. ASCII or UTF-8 C
75 * strings) for the names of attributes, rather than a byte string
76 * bounded by an explicit length. If some day we want to support names
77 * in character sets which have embedded zeros (eg. UTF-16, UTF-32),
78 * we'll have to add routines for using length-bounded strings.
79 */
80
81 #include <sys/dmu.h>
82
83 #ifdef __cplusplus
84 extern "C" {
85 #endif
86
87 /*
88 * The matchtype specifies which entry will be accessed.
89 * MT_EXACT: only find an exact match (non-normalized)
90 * MT_FIRST: find the "first" normalized (case and Unicode
91 * form) match; the designated "first" match will not change as long
92 * as the set of entries with this normalization doesn't change
93 * MT_BEST: if there is an exact match, find that, otherwise find the
94 * first normalized match
95 */
96 typedef enum matchtype
97 {
98 MT_EXACT,
99 MT_BEST,
100 MT_FIRST
101 } matchtype_t;
102
103 typedef enum zap_flags {
104 /* Use 64-bit hash value (serialized cursors will always use 64-bits) */
105 ZAP_FLAG_HASH64 = 1 << 0,
106 /* Key is binary, not string (zap_add_uint64() can be used) */
107 ZAP_FLAG_UINT64_KEY = 1 << 1,
108 /*
109 * First word of key (which must be an array of uint64) is
110 * already randomly distributed.
111 */
112 ZAP_FLAG_PRE_HASHED_KEY = 1 << 2,
113 } zap_flags_t;
114
115 /*
116 * Create a new zapobj with no attributes and return its object number.
117 * MT_EXACT will cause the zap object to only support MT_EXACT lookups,
118 * otherwise any matchtype can be used for lookups.
119 *
120 * normflags specifies what normalization will be done. values are:
121 * 0: no normalization (legacy on-disk format, supports MT_EXACT matching
122 * only)
123 * U8_TEXTPREP_TOLOWER: case normalization will be performed.
124 * MT_FIRST/MT_BEST matching will find entries that match without
125 * regard to case (eg. looking for "foo" can find an entry "Foo").
126 * Eventually, other flags will permit unicode normalization as well.
127 */
128 uint64_t zap_create(objset_t *ds, dmu_object_type_t ot,
129 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
130 uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot,
131 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
132 uint64_t zap_create_flags(objset_t *os, int normflags, zap_flags_t flags,
133 dmu_object_type_t ot, int leaf_blockshift, int indirect_blockshift,
134 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
135
136 /*
137 * Create a new zapobj with no attributes from the given (unallocated)
138 * object number.
139 */
140 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot,
141 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
142 int zap_create_claim_norm(objset_t *ds, uint64_t obj,
143 int normflags, dmu_object_type_t ot,
144 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
145
146 /*
147 * The zapobj passed in must be a valid ZAP object for all of the
148 * following routines.
149 */
150
151 /*
152 * Destroy this zapobj and all its attributes.
153 *
154 * Frees the object number using dmu_object_free.
155 */
156 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx);
157
158 /*
159 * Manipulate attributes.
160 *
161 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8.
162 */
163
164 /*
165 * Retrieve the contents of the attribute with the given name.
166 *
167 * If the requested attribute does not exist, the call will fail and
168 * return ENOENT.
169 *
170 * If 'integer_size' is smaller than the attribute's integer size, the
171 * call will fail and return EINVAL.
172 *
173 * If 'integer_size' is equal to or larger than the attribute's integer
174 * size, the call will succeed and return 0. * When converting to a
175 * larger integer size, the integers will be treated as unsigned (ie. no
176 * sign-extension will be performed).
177 *
178 * 'num_integers' is the length (in integers) of 'buf'.
179 *
180 * If the attribute is longer than the buffer, as many integers as will
181 * fit will be transferred to 'buf'. If the entire attribute was not
182 * transferred, the call will return EOVERFLOW.
183 *
184 * If rn_len is nonzero, realname will be set to the name of the found
185 * entry (which may be different from the requested name if matchtype is
186 * not MT_EXACT).
187 *
188 * If normalization_conflictp is not NULL, it will be set if there is
189 * another name with the same case/unicode normalized form.
190 */
191 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name,
192 uint64_t integer_size, uint64_t num_integers, void *buf);
193 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name,
194 uint64_t integer_size, uint64_t num_integers, void *buf,
195 matchtype_t mt, char *realname, int rn_len,
196 boolean_t *normalization_conflictp);
197 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
198 int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf);
199 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name);
200 int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
201 int key_numints);
202
203 int zap_count_write(objset_t *os, uint64_t zapobj, const char *name,
204 int add, uint64_t *towrite, uint64_t *tooverwrite);
205
206 /*
207 * Create an attribute with the given name and value.
208 *
209 * If an attribute with the given name already exists, the call will
210 * fail and return EEXIST.
211 */
212 int zap_add(objset_t *ds, uint64_t zapobj, const char *key,
213 int integer_size, uint64_t num_integers,
214 const void *val, dmu_tx_t *tx);
215 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key,
216 int key_numints, int integer_size, uint64_t num_integers,
217 const void *val, dmu_tx_t *tx);
218
219 /*
220 * Set the attribute with the given name to the given value. If an
221 * attribute with the given name does not exist, it will be created. If
222 * an attribute with the given name already exists, the previous value
223 * will be overwritten. The integer_size may be different from the
224 * existing attribute's integer size, in which case the attribute's
225 * integer size will be updated to the new value.
226 */
227 int zap_update(objset_t *ds, uint64_t zapobj, const char *name,
228 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
229 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
230 int key_numints,
231 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
232
233 /*
234 * Get the length (in integers) and the integer size of the specified
235 * attribute.
236 *
237 * If the requested attribute does not exist, the call will fail and
238 * return ENOENT.
239 */
240 int zap_length(objset_t *ds, uint64_t zapobj, const char *name,
241 uint64_t *integer_size, uint64_t *num_integers);
242 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
243 int key_numints, uint64_t *integer_size, uint64_t *num_integers);
244
245 /*
246 * Remove the specified attribute.
247 *
248 * If the specified attribute does not exist, the call will fail and
249 * return ENOENT.
250 */
251 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx);
252 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name,
253 matchtype_t mt, dmu_tx_t *tx);
254 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
255 int key_numints, dmu_tx_t *tx);
256
257 /*
258 * Returns (in *count) the number of attributes in the specified zap
259 * object.
260 */
261 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count);
262
263 /*
264 * Returns (in name) the name of the entry whose (value & mask)
265 * (za_first_integer) is value, or ENOENT if not found. The string
266 * pointed to by name must be at least 256 bytes long. If mask==0, the
267 * match must be exact (ie, same as mask=-1ULL).
268 */
269 int zap_value_search(objset_t *os, uint64_t zapobj,
270 uint64_t value, uint64_t mask, char *name);
271
272 /*
273 * Transfer all the entries from fromobj into intoobj. Only works on
274 * int_size=8 num_integers=1 values. Fails if there are any duplicated
275 * entries.
276 */
277 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx);
278
279 /* Same as zap_join, but set the values to 'value'. */
280 int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
281 uint64_t value, dmu_tx_t *tx);
282
283 /* Same as zap_join, but add together any duplicated entries. */
284 int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
285 dmu_tx_t *tx);
286
287 /*
288 * Manipulate entries where the name + value are the "same" (the name is
289 * a stringified version of the value).
290 */
291 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
292 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
293 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value);
294 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
295 dmu_tx_t *tx);
296
297 /* Here the key is an int and the value is a different int. */
298 int zap_add_int_key(objset_t *os, uint64_t obj,
299 uint64_t key, uint64_t value, dmu_tx_t *tx);
300 int zap_lookup_int_key(objset_t *os, uint64_t obj,
301 uint64_t key, uint64_t *valuep);
302
303 /*
304 * They name is a stringified version of key; increment its value by
305 * delta. Zero values will be zap_remove()-ed.
306 */
307 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
308 dmu_tx_t *tx);
309 int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,
310 dmu_tx_t *tx);
311
312 struct zap;
313 struct zap_leaf;
314 typedef struct zap_cursor {
315 /* This structure is opaque! */
316 objset_t *zc_objset;
317 struct zap *zc_zap;
318 struct zap_leaf *zc_leaf;
319 uint64_t zc_zapobj;
320 uint64_t zc_serialized;
321 uint64_t zc_hash;
322 uint32_t zc_cd;
323 } zap_cursor_t;
324
325 typedef struct {
326 int za_integer_length;
327 /*
328 * za_normalization_conflict will be set if there are additional
329 * entries with this normalized form (eg, "foo" and "Foo").
330 */
331 boolean_t za_normalization_conflict;
332 uint64_t za_num_integers;
333 uint64_t za_first_integer; /* no sign extension for <8byte ints */
334 char za_name[MAXNAMELEN];
335 } zap_attribute_t;
336
337 /*
338 * The interface for listing all the attributes of a zapobj can be
339 * thought of as cursor moving down a list of the attributes one by
340 * one. The cookie returned by the zap_cursor_serialize routine is
341 * persistent across system calls (and across reboot, even).
342 */
343
344 /*
345 * Initialize a zap cursor, pointing to the "first" attribute of the
346 * zapobj. You must _fini the cursor when you are done with it.
347 */
348 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj);
349 void zap_cursor_fini(zap_cursor_t *zc);
350
351 /*
352 * Get the attribute currently pointed to by the cursor. Returns
353 * ENOENT if at the end of the attributes.
354 */
355 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za);
356
357 /*
358 * Advance the cursor to the next attribute.
359 */
360 void zap_cursor_advance(zap_cursor_t *zc);
361
362 /*
363 * Get a persistent cookie pointing to the current position of the zap
364 * cursor. The low 4 bits in the cookie are always zero, and thus can
365 * be used as to differentiate a serialized cookie from a different type
366 * of value. The cookie will be less than 2^32 as long as there are
367 * fewer than 2^22 (4.2 million) entries in the zap object.
368 */
369 uint64_t zap_cursor_serialize(zap_cursor_t *zc);
370
371 /*
372 * Advance the cursor to the attribute having the given key.
373 */
374 int zap_cursor_move_to_key(zap_cursor_t *zc, const char *name, matchtype_t mt);
375
376 /*
377 * Initialize a zap cursor pointing to the position recorded by
378 * zap_cursor_serialize (in the "serialized" argument). You can also
379 * use a "serialized" argument of 0 to start at the beginning of the
380 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to
381 * zap_cursor_init(...).)
382 */
383 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds,
384 uint64_t zapobj, uint64_t serialized);
385
386
387 #define ZAP_HISTOGRAM_SIZE 10
388
389 typedef struct zap_stats {
390 /*
391 * Size of the pointer table (in number of entries).
392 * This is always a power of 2, or zero if it's a microzap.
393 * In general, it should be considerably greater than zs_num_leafs.
394 */
395 uint64_t zs_ptrtbl_len;
396
397 uint64_t zs_blocksize; /* size of zap blocks */
398
399 /*
400 * The number of blocks used. Note that some blocks may be
401 * wasted because old ptrtbl's and large name/value blocks are
402 * not reused. (Although their space is reclaimed, we don't
403 * reuse those offsets in the object.)
404 */
405 uint64_t zs_num_blocks;
406
407 /*
408 * Pointer table values from zap_ptrtbl in the zap_phys_t
409 */
410 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */
411 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */
412 uint64_t zs_ptrtbl_zt_blk; /* starting block number */
413 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */
414 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */
415
416 /*
417 * Values of the other members of the zap_phys_t
418 */
419 uint64_t zs_block_type; /* ZBT_HEADER */
420 uint64_t zs_magic; /* ZAP_MAGIC */
421 uint64_t zs_num_leafs; /* The number of leaf blocks */
422 uint64_t zs_num_entries; /* The number of zap entries */
423 uint64_t zs_salt; /* salt to stir into hash function */
424
425 /*
426 * Histograms. For all histograms, the last index
427 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater
428 * than what can be represented. For example
429 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number
430 * of leafs with more than 45 entries.
431 */
432
433 /*
434 * zs_leafs_with_n_pointers[n] is the number of leafs with
435 * 2^n pointers to it.
436 */
437 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE];
438
439 /*
440 * zs_leafs_with_n_entries[n] is the number of leafs with
441 * [n*5, (n+1)*5) entries. In the current implementation, there
442 * can be at most 55 entries in any block, but there may be
443 * fewer if the name or value is large, or the block is not
444 * completely full.
445 */
446 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE];
447
448 /*
449 * zs_leafs_n_tenths_full[n] is the number of leafs whose
450 * fullness is in the range [n/10, (n+1)/10).
451 */
452 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE];
453
454 /*
455 * zs_entries_using_n_chunks[n] is the number of entries which
456 * consume n 24-byte chunks. (Note, large names/values only use
457 * one chunk, but contribute to zs_num_blocks_large.)
458 */
459 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE];
460
461 /*
462 * zs_buckets_with_n_entries[n] is the number of buckets (each
463 * leaf has 64 buckets) with n entries.
464 * zs_buckets_with_n_entries[1] should be very close to
465 * zs_num_entries.
466 */
467 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE];
468 } zap_stats_t;
469
470 /*
471 * Get statistics about a ZAP object. Note: you need to be aware of the
472 * internal implementation of the ZAP to correctly interpret some of the
473 * statistics. This interface shouldn't be relied on unless you really
474 * know what you're doing.
475 */
476 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs);
477
478 #ifdef __cplusplus
479 }
480 #endif
481
482 #endif /* _SYS_ZAP_H */