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 * Initialize an already-allocated object.
145 */
146 void mzap_create_impl(objset_t *os, uint64_t obj, int normflags,
147 zap_flags_t flags, dmu_tx_t *tx);
148
149 /*
150 * Create a new zapobj with no attributes from the given (unallocated)
151 * object number.
152 */
153 int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot,
154 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
155 int zap_create_claim_norm(objset_t *ds, uint64_t obj,
156 int normflags, dmu_object_type_t ot,
157 dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
158
159 /*
160 * The zapobj passed in must be a valid ZAP object for all of the
161 * following routines.
162 */
163
164 /*
165 * Destroy this zapobj and all its attributes.
166 *
167 * Frees the object number using dmu_object_free.
168 */
169 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx);
170
171 /*
172 * Manipulate attributes.
173 *
174 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8.
175 */
176
177 /*
178 * Retrieve the contents of the attribute with the given name.
179 *
180 * If the requested attribute does not exist, the call will fail and
181 * return ENOENT.
182 *
183 * If 'integer_size' is smaller than the attribute's integer size, the
184 * call will fail and return EINVAL.
185 *
186 * If 'integer_size' is equal to or larger than the attribute's integer
187 * size, the call will succeed and return 0.
188 *
189 * When converting to a larger integer size, the integers will be treated as
190 * unsigned (ie. no sign-extension will be performed).
191 *
192 * 'num_integers' is the length (in integers) of 'buf'.
193 *
194 * If the attribute is longer than the buffer, as many integers as will
195 * fit will be transferred to 'buf'. If the entire attribute was not
196 * transferred, the call will return EOVERFLOW.
197 */
198 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name,
199 uint64_t integer_size, uint64_t num_integers, void *buf);
200
201 /*
202 * If rn_len is nonzero, realname will be set to the name of the found
203 * entry (which may be different from the requested name if matchtype is
204 * not MT_EXACT).
205 *
206 * If normalization_conflictp is not NULL, it will be set if there is
207 * another name with the same case/unicode normalized form.
208 */
209 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name,
210 uint64_t integer_size, uint64_t num_integers, void *buf,
211 matchtype_t mt, char *realname, int rn_len,
212 boolean_t *normalization_conflictp);
213 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
214 int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf);
215 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name);
216 int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
217 int key_numints);
218
219 int zap_count_write(objset_t *os, uint64_t zapobj, const char *name,
220 int add, uint64_t *towrite, uint64_t *tooverwrite);
221
222 /*
223 * Create an attribute with the given name and value.
224 *
225 * If an attribute with the given name already exists, the call will
226 * fail and return EEXIST.
227 */
228 int zap_add(objset_t *ds, uint64_t zapobj, const char *key,
229 int integer_size, uint64_t num_integers,
230 const void *val, dmu_tx_t *tx);
231 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key,
232 int key_numints, int integer_size, uint64_t num_integers,
233 const void *val, dmu_tx_t *tx);
234
235 /*
236 * Set the attribute with the given name to the given value. If an
237 * attribute with the given name does not exist, it will be created. If
238 * an attribute with the given name already exists, the previous value
239 * will be overwritten. The integer_size may be different from the
240 * existing attribute's integer size, in which case the attribute's
241 * integer size will be updated to the new value.
242 */
243 int zap_update(objset_t *ds, uint64_t zapobj, const char *name,
244 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
245 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
246 int key_numints,
247 int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
248
249 /*
250 * Get the length (in integers) and the integer size of the specified
251 * attribute.
252 *
253 * If the requested attribute does not exist, the call will fail and
254 * return ENOENT.
255 */
256 int zap_length(objset_t *ds, uint64_t zapobj, const char *name,
257 uint64_t *integer_size, uint64_t *num_integers);
258 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
259 int key_numints, uint64_t *integer_size, uint64_t *num_integers);
260
261 /*
262 * Remove the specified attribute.
263 *
264 * If the specified attribute does not exist, the call will fail and
265 * return ENOENT.
266 */
267 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx);
268 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name,
269 matchtype_t mt, dmu_tx_t *tx);
270 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
271 int key_numints, dmu_tx_t *tx);
272
273 /*
274 * Returns (in *count) the number of attributes in the specified zap
275 * object.
276 */
277 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count);
278
279 /*
280 * Returns (in name) the name of the entry whose (value & mask)
281 * (za_first_integer) is value, or ENOENT if not found. The string
282 * pointed to by name must be at least 256 bytes long. If mask==0, the
283 * match must be exact (ie, same as mask=-1ULL).
284 */
285 int zap_value_search(objset_t *os, uint64_t zapobj,
286 uint64_t value, uint64_t mask, char *name);
287
288 /*
289 * Transfer all the entries from fromobj into intoobj. Only works on
290 * int_size=8 num_integers=1 values. Fails if there are any duplicated
291 * entries.
292 */
293 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx);
294
295 /* Same as zap_join, but set the values to 'value'. */
296 int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
297 uint64_t value, dmu_tx_t *tx);
298
299 /* Same as zap_join, but add together any duplicated entries. */
300 int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
301 dmu_tx_t *tx);
302
303 /*
304 * Manipulate entries where the name + value are the "same" (the name is
305 * a stringified version of the value).
306 */
307 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
308 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
309 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value);
310 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
311 dmu_tx_t *tx);
312
313 /* Here the key is an int and the value is a different int. */
314 int zap_add_int_key(objset_t *os, uint64_t obj,
315 uint64_t key, uint64_t value, dmu_tx_t *tx);
316 int zap_update_int_key(objset_t *os, uint64_t obj,
317 uint64_t key, uint64_t value, dmu_tx_t *tx);
318 int zap_lookup_int_key(objset_t *os, uint64_t obj,
319 uint64_t key, uint64_t *valuep);
320
321 int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,
322 dmu_tx_t *tx);
323
324 struct zap;
325 struct zap_leaf;
326 typedef struct zap_cursor {
327 /* This structure is opaque! */
328 objset_t *zc_objset;
329 struct zap *zc_zap;
330 struct zap_leaf *zc_leaf;
331 uint64_t zc_zapobj;
332 uint64_t zc_serialized;
333 uint64_t zc_hash;
334 uint32_t zc_cd;
335 } zap_cursor_t;
336
337 typedef struct {
338 int za_integer_length;
339 /*
340 * za_normalization_conflict will be set if there are additional
341 * entries with this normalized form (eg, "foo" and "Foo").
342 */
343 boolean_t za_normalization_conflict;
344 uint64_t za_num_integers;
345 uint64_t za_first_integer; /* no sign extension for <8byte ints */
346 char za_name[MAXNAMELEN];
347 } zap_attribute_t;
348
349 /*
350 * The interface for listing all the attributes of a zapobj can be
351 * thought of as cursor moving down a list of the attributes one by
352 * one. The cookie returned by the zap_cursor_serialize routine is
353 * persistent across system calls (and across reboot, even).
354 */
355
356 /*
357 * Initialize a zap cursor, pointing to the "first" attribute of the
358 * zapobj. You must _fini the cursor when you are done with it.
359 */
360 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj);
361 void zap_cursor_fini(zap_cursor_t *zc);
362
363 /*
364 * Get the attribute currently pointed to by the cursor. Returns
365 * ENOENT if at the end of the attributes.
366 */
367 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za);
368
369 /*
370 * Advance the cursor to the next attribute.
371 */
372 void zap_cursor_advance(zap_cursor_t *zc);
373
374 /*
375 * Get a persistent cookie pointing to the current position of the zap
376 * cursor. The low 4 bits in the cookie are always zero, and thus can
377 * be used as to differentiate a serialized cookie from a different type
378 * of value. The cookie will be less than 2^32 as long as there are
379 * fewer than 2^22 (4.2 million) entries in the zap object.
380 */
381 uint64_t zap_cursor_serialize(zap_cursor_t *zc);
382
383 /*
384 * Initialize a zap cursor pointing to the position recorded by
385 * zap_cursor_serialize (in the "serialized" argument). You can also
386 * use a "serialized" argument of 0 to start at the beginning of the
387 * zapobj (ie. zap_cursor_init_serialized(..., 0) is equivalent to
388 * zap_cursor_init(...).)
389 */
390 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds,
391 uint64_t zapobj, uint64_t serialized);
392
393
394 #define ZAP_HISTOGRAM_SIZE 10
395
396 typedef struct zap_stats {
397 /*
398 * Size of the pointer table (in number of entries).
399 * This is always a power of 2, or zero if it's a microzap.
400 * In general, it should be considerably greater than zs_num_leafs.
401 */
402 uint64_t zs_ptrtbl_len;
403
404 uint64_t zs_blocksize; /* size of zap blocks */
405
406 /*
407 * The number of blocks used. Note that some blocks may be
408 * wasted because old ptrtbl's and large name/value blocks are
409 * not reused. (Although their space is reclaimed, we don't
410 * reuse those offsets in the object.)
411 */
412 uint64_t zs_num_blocks;
413
414 /*
415 * Pointer table values from zap_ptrtbl in the zap_phys_t
416 */
417 uint64_t zs_ptrtbl_nextblk; /* next (larger) copy start block */
418 uint64_t zs_ptrtbl_blks_copied; /* number source blocks copied */
419 uint64_t zs_ptrtbl_zt_blk; /* starting block number */
420 uint64_t zs_ptrtbl_zt_numblks; /* number of blocks */
421 uint64_t zs_ptrtbl_zt_shift; /* bits to index it */
422
423 /*
424 * Values of the other members of the zap_phys_t
425 */
426 uint64_t zs_block_type; /* ZBT_HEADER */
427 uint64_t zs_magic; /* ZAP_MAGIC */
428 uint64_t zs_num_leafs; /* The number of leaf blocks */
429 uint64_t zs_num_entries; /* The number of zap entries */
430 uint64_t zs_salt; /* salt to stir into hash function */
431
432 /*
433 * Histograms. For all histograms, the last index
434 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater
435 * than what can be represented. For example
436 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number
437 * of leafs with more than 45 entries.
438 */
439
440 /*
441 * zs_leafs_with_n_pointers[n] is the number of leafs with
442 * 2^n pointers to it.
443 */
444 uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE];
445
446 /*
447 * zs_leafs_with_n_entries[n] is the number of leafs with
448 * [n*5, (n+1)*5) entries. In the current implementation, there
449 * can be at most 55 entries in any block, but there may be
450 * fewer if the name or value is large, or the block is not
451 * completely full.
452 */
453 uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE];
454
455 /*
456 * zs_leafs_n_tenths_full[n] is the number of leafs whose
457 * fullness is in the range [n/10, (n+1)/10).
458 */
459 uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE];
460
461 /*
462 * zs_entries_using_n_chunks[n] is the number of entries which
463 * consume n 24-byte chunks. (Note, large names/values only use
464 * one chunk, but contribute to zs_num_blocks_large.)
465 */
466 uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE];
467
468 /*
469 * zs_buckets_with_n_entries[n] is the number of buckets (each
470 * leaf has 64 buckets) with n entries.
471 * zs_buckets_with_n_entries[1] should be very close to
472 * zs_num_entries.
473 */
474 uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE];
475 } zap_stats_t;
476
477 /*
478 * Get statistics about a ZAP object. Note: you need to be aware of the
479 * internal implementation of the ZAP to correctly interpret some of the
480 * statistics. This interface shouldn't be relied on unless you really
481 * know what you're doing.
482 */
483 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs);
484
485 #ifdef __cplusplus
486 }
487 #endif
488
489 #endif /* _SYS_ZAP_H */