xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/zap.h (revision 52abb70e)
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  *
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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 /*
23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
25  * Copyright 2017 Nexenta Systems, Inc.
26  */
27 
28 #ifndef	_SYS_ZAP_H
29 #define	_SYS_ZAP_H
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 #include <sys/refcount.h>
86 
87 #ifdef	__cplusplus
88 extern "C" {
89 #endif
90 
91 /*
92  * Specifies matching criteria for ZAP lookups.
93  * MT_NORMALIZE		Use ZAP normalization flags, which can include both
94  *			unicode normalization and case-insensitivity.
95  * MT_MATCH_CASE	Do case-sensitive lookups even if MT_NORMALIZE is
96  *			specified and ZAP normalization flags include
97  *			U8_TEXTPREP_TOUPPER.
98  */
99 typedef enum matchtype {
100 	MT_NORMALIZE = 1 << 0,
101 	MT_MATCH_CASE = 1 << 1,
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  *
119  * dnodesize specifies the on-disk size of the dnode for the new zapobj.
120  * Valid values are multiples of 512 up to DNODE_MAX_SIZE.
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_dnsize(objset_t *ds, dmu_object_type_t ot,
125     dmu_object_type_t bonustype, int bonuslen, int dnodesize, dmu_tx_t *tx);
126 uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot,
127     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
128 uint64_t zap_create_norm_dnsize(objset_t *ds, int normflags,
129     dmu_object_type_t ot, dmu_object_type_t bonustype, int bonuslen,
130     int dnodesize, dmu_tx_t *tx);
131 uint64_t zap_create_flags(objset_t *os, int normflags, zap_flags_t flags,
132     dmu_object_type_t ot, int leaf_blockshift, int indirect_blockshift,
133     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
134 uint64_t zap_create_flags_dnsize(objset_t *os, int normflags,
135     zap_flags_t flags, dmu_object_type_t ot, int leaf_blockshift,
136     int indirect_blockshift, dmu_object_type_t bonustype, int bonuslen,
137     int dnodesize, dmu_tx_t *tx);
138 uint64_t zap_create_link(objset_t *os, dmu_object_type_t ot,
139     uint64_t parent_obj, const char *name, dmu_tx_t *tx);
140 uint64_t zap_create_link_dnsize(objset_t *os, dmu_object_type_t ot,
141     uint64_t parent_obj, const char *name, int dnodesize, 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_dnsize(objset_t *ds, uint64_t obj, dmu_object_type_t ot,
156     dmu_object_type_t bonustype, int bonuslen, int dnodesize, dmu_tx_t *tx);
157 int zap_create_claim_norm(objset_t *ds, uint64_t obj,
158     int normflags, dmu_object_type_t ot,
159     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
160 int zap_create_claim_norm_dnsize(objset_t *ds, uint64_t obj,
161     int normflags, dmu_object_type_t ot,
162     dmu_object_type_t bonustype, int bonuslen, int dnodesize, dmu_tx_t *tx);
163 
164 /*
165  * The zapobj passed in must be a valid ZAP object for all of the
166  * following routines.
167  */
168 
169 /*
170  * Destroy this zapobj and all its attributes.
171  *
172  * Frees the object number using dmu_object_free.
173  */
174 int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx);
175 
176 /*
177  * Manipulate attributes.
178  *
179  * 'integer_size' is in bytes, and must be 1, 2, 4, or 8.
180  */
181 
182 /*
183  * Retrieve the contents of the attribute with the given name.
184  *
185  * If the requested attribute does not exist, the call will fail and
186  * return ENOENT.
187  *
188  * If 'integer_size' is smaller than the attribute's integer size, the
189  * call will fail and return EINVAL.
190  *
191  * If 'integer_size' is equal to or larger than the attribute's integer
192  * size, the call will succeed and return 0.
193  *
194  * When converting to a larger integer size, the integers will be treated as
195  * unsigned (ie. no sign-extension will be performed).
196  *
197  * 'num_integers' is the length (in integers) of 'buf'.
198  *
199  * If the attribute is longer than the buffer, as many integers as will
200  * fit will be transferred to 'buf'.  If the entire attribute was not
201  * transferred, the call will return EOVERFLOW.
202  */
203 int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name,
204     uint64_t integer_size, uint64_t num_integers, void *buf);
205 
206 /*
207  * If rn_len is nonzero, realname will be set to the name of the found
208  * entry (which may be different from the requested name if matchtype is
209  * not MT_EXACT).
210  *
211  * If normalization_conflictp is not NULL, it will be set if there is
212  * another name with the same case/unicode normalized form.
213  */
214 int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name,
215     uint64_t integer_size, uint64_t num_integers, void *buf,
216     matchtype_t mt, char *realname, int rn_len,
217     boolean_t *normalization_conflictp);
218 int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
219     int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf);
220 int zap_contains(objset_t *ds, uint64_t zapobj, const char *name);
221 int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
222     int key_numints);
223 int zap_lookup_by_dnode(dnode_t *dn, const char *name,
224     uint64_t integer_size, uint64_t num_integers, void *buf);
225 int zap_lookup_norm_by_dnode(dnode_t *dn, const char *name,
226     uint64_t integer_size, uint64_t num_integers, void *buf,
227     matchtype_t mt, char *realname, int rn_len,
228     boolean_t *ncp);
229 
230 int zap_count_write_by_dnode(dnode_t *dn, const char *name,
231     int add, zfs_refcount_t *towrite, zfs_refcount_t *tooverwrite);
232 
233 /*
234  * Create an attribute with the given name and value.
235  *
236  * If an attribute with the given name already exists, the call will
237  * fail and return EEXIST.
238  */
239 int zap_add(objset_t *ds, uint64_t zapobj, const char *key,
240     int integer_size, uint64_t num_integers,
241     const void *val, dmu_tx_t *tx);
242 int zap_add_by_dnode(dnode_t *dn, const char *key,
243     int integer_size, uint64_t num_integers,
244     const void *val, dmu_tx_t *tx);
245 int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key,
246     int key_numints, int integer_size, uint64_t num_integers,
247     const void *val, dmu_tx_t *tx);
248 
249 /*
250  * Set the attribute with the given name to the given value.  If an
251  * attribute with the given name does not exist, it will be created.  If
252  * an attribute with the given name already exists, the previous value
253  * will be overwritten.  The integer_size may be different from the
254  * existing attribute's integer size, in which case the attribute's
255  * integer size will be updated to the new value.
256  */
257 int zap_update(objset_t *ds, uint64_t zapobj, const char *name,
258     int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
259 int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
260     int key_numints,
261     int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);
262 
263 /*
264  * Get the length (in integers) and the integer size of the specified
265  * attribute.
266  *
267  * If the requested attribute does not exist, the call will fail and
268  * return ENOENT.
269  */
270 int zap_length(objset_t *ds, uint64_t zapobj, const char *name,
271     uint64_t *integer_size, uint64_t *num_integers);
272 int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
273     int key_numints, uint64_t *integer_size, uint64_t *num_integers);
274 
275 /*
276  * Remove the specified attribute.
277  *
278  * If the specified attribute does not exist, the call will fail and
279  * return ENOENT.
280  */
281 int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx);
282 int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name,
283     matchtype_t mt, dmu_tx_t *tx);
284 int zap_remove_by_dnode(dnode_t *dn, const char *name, dmu_tx_t *tx);
285 int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,
286     int key_numints, dmu_tx_t *tx);
287 
288 /*
289  * Returns (in *count) the number of attributes in the specified zap
290  * object.
291  */
292 int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count);
293 
294 /*
295  * Returns (in name) the name of the entry whose (value & mask)
296  * (za_first_integer) is value, or ENOENT if not found.  The string
297  * pointed to by name must be at least 256 bytes long.  If mask==0, the
298  * match must be exact (ie, same as mask=-1ULL).
299  */
300 int zap_value_search(objset_t *os, uint64_t zapobj,
301     uint64_t value, uint64_t mask, char *name);
302 
303 /*
304  * Transfer all the entries from fromobj into intoobj.  Only works on
305  * int_size=8 num_integers=1 values.  Fails if there are any duplicated
306  * entries.
307  */
308 int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx);
309 
310 /* Same as zap_join, but set the values to 'value'. */
311 int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
312     uint64_t value, dmu_tx_t *tx);
313 
314 /* Same as zap_join, but add together any duplicated entries. */
315 int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
316     dmu_tx_t *tx);
317 
318 /*
319  * Manipulate entries where the name + value are the "same" (the name is
320  * a stringified version of the value).
321  */
322 int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
323 int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);
324 int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value);
325 int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
326     dmu_tx_t *tx);
327 
328 /* Here the key is an int and the value is a different int. */
329 int zap_add_int_key(objset_t *os, uint64_t obj,
330     uint64_t key, uint64_t value, dmu_tx_t *tx);
331 int zap_update_int_key(objset_t *os, uint64_t obj,
332     uint64_t key, uint64_t value, dmu_tx_t *tx);
333 int zap_lookup_int_key(objset_t *os, uint64_t obj,
334     uint64_t key, uint64_t *valuep);
335 
336 int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,
337     dmu_tx_t *tx);
338 
339 struct zap;
340 struct zap_leaf;
341 typedef struct zap_cursor {
342 	/* This structure is opaque! */
343 	objset_t *zc_objset;
344 	struct zap *zc_zap;
345 	struct zap_leaf *zc_leaf;
346 	uint64_t zc_zapobj;
347 	uint64_t zc_serialized;
348 	uint64_t zc_hash;
349 	uint32_t zc_cd;
350 	boolean_t zc_prefetch;
351 } zap_cursor_t;
352 
353 typedef struct {
354 	int za_integer_length;
355 	/*
356 	 * za_normalization_conflict will be set if there are additional
357 	 * entries with this normalized form (eg, "foo" and "Foo").
358 	 */
359 	boolean_t za_normalization_conflict;
360 	uint64_t za_num_integers;
361 	uint64_t za_first_integer;	/* no sign extension for <8byte ints */
362 	char za_name[ZAP_MAXNAMELEN];
363 } zap_attribute_t;
364 
365 /*
366  * The interface for listing all the attributes of a zapobj can be
367  * thought of as cursor moving down a list of the attributes one by
368  * one.  The cookie returned by the zap_cursor_serialize routine is
369  * persistent across system calls (and across reboot, even).
370  */
371 
372 /*
373  * Initialize a zap cursor, pointing to the "first" attribute of the
374  * zapobj.  You must _fini the cursor when you are done with it.
375  */
376 void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj);
377 void zap_cursor_init_noprefetch(zap_cursor_t *zc, objset_t *os,
378     uint64_t zapobj);
379 void zap_cursor_fini(zap_cursor_t *zc);
380 
381 /*
382  * Get the attribute currently pointed to by the cursor.  Returns
383  * ENOENT if at the end of the attributes.
384  */
385 int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za);
386 
387 /*
388  * Advance the cursor to the next attribute.
389  */
390 void zap_cursor_advance(zap_cursor_t *zc);
391 
392 /*
393  * Get a persistent cookie pointing to the current position of the zap
394  * cursor.  The low 4 bits in the cookie are always zero, and thus can
395  * be used as to differentiate a serialized cookie from a different type
396  * of value.  The cookie will be less than 2^32 as long as there are
397  * fewer than 2^22 (4.2 million) entries in the zap object.
398  */
399 uint64_t zap_cursor_serialize(zap_cursor_t *zc);
400 
401 /*
402  * Initialize a zap cursor pointing to the position recorded by
403  * zap_cursor_serialize (in the "serialized" argument).  You can also
404  * use a "serialized" argument of 0 to start at the beginning of the
405  * zapobj (ie.  zap_cursor_init_serialized(..., 0) is equivalent to
406  * zap_cursor_init(...).)
407  */
408 void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds,
409     uint64_t zapobj, uint64_t serialized);
410 
411 
412 #define	ZAP_HISTOGRAM_SIZE 10
413 
414 typedef struct zap_stats {
415 	/*
416 	 * Size of the pointer table (in number of entries).
417 	 * This is always a power of 2, or zero if it's a microzap.
418 	 * In general, it should be considerably greater than zs_num_leafs.
419 	 */
420 	uint64_t zs_ptrtbl_len;
421 
422 	uint64_t zs_blocksize;		/* size of zap blocks */
423 
424 	/*
425 	 * The number of blocks used.  Note that some blocks may be
426 	 * wasted because old ptrtbl's and large name/value blocks are
427 	 * not reused.  (Although their space is reclaimed, we don't
428 	 * reuse those offsets in the object.)
429 	 */
430 	uint64_t zs_num_blocks;
431 
432 	/*
433 	 * Pointer table values from zap_ptrtbl in the zap_phys_t
434 	 */
435 	uint64_t zs_ptrtbl_nextblk;	  /* next (larger) copy start block */
436 	uint64_t zs_ptrtbl_blks_copied;   /* number source blocks copied */
437 	uint64_t zs_ptrtbl_zt_blk;	  /* starting block number */
438 	uint64_t zs_ptrtbl_zt_numblks;    /* number of blocks */
439 	uint64_t zs_ptrtbl_zt_shift;	  /* bits to index it */
440 
441 	/*
442 	 * Values of the other members of the zap_phys_t
443 	 */
444 	uint64_t zs_block_type;		/* ZBT_HEADER */
445 	uint64_t zs_magic;		/* ZAP_MAGIC */
446 	uint64_t zs_num_leafs;		/* The number of leaf blocks */
447 	uint64_t zs_num_entries;	/* The number of zap entries */
448 	uint64_t zs_salt;		/* salt to stir into hash function */
449 
450 	/*
451 	 * Histograms.  For all histograms, the last index
452 	 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater
453 	 * than what can be represented.  For example
454 	 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number
455 	 * of leafs with more than 45 entries.
456 	 */
457 
458 	/*
459 	 * zs_leafs_with_n_pointers[n] is the number of leafs with
460 	 * 2^n pointers to it.
461 	 */
462 	uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE];
463 
464 	/*
465 	 * zs_leafs_with_n_entries[n] is the number of leafs with
466 	 * [n*5, (n+1)*5) entries.  In the current implementation, there
467 	 * can be at most 55 entries in any block, but there may be
468 	 * fewer if the name or value is large, or the block is not
469 	 * completely full.
470 	 */
471 	uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE];
472 
473 	/*
474 	 * zs_leafs_n_tenths_full[n] is the number of leafs whose
475 	 * fullness is in the range [n/10, (n+1)/10).
476 	 */
477 	uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE];
478 
479 	/*
480 	 * zs_entries_using_n_chunks[n] is the number of entries which
481 	 * consume n 24-byte chunks.  (Note, large names/values only use
482 	 * one chunk, but contribute to zs_num_blocks_large.)
483 	 */
484 	uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE];
485 
486 	/*
487 	 * zs_buckets_with_n_entries[n] is the number of buckets (each
488 	 * leaf has 64 buckets) with n entries.
489 	 * zs_buckets_with_n_entries[1] should be very close to
490 	 * zs_num_entries.
491 	 */
492 	uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE];
493 } zap_stats_t;
494 
495 /*
496  * Get statistics about a ZAP object.  Note: you need to be aware of the
497  * internal implementation of the ZAP to correctly interpret some of the
498  * statistics.  This interface shouldn't be relied on unless you really
499  * know what you're doing.
500  */
501 int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs);
502 
503 #ifdef	__cplusplus
504 }
505 #endif
506 
507 #endif	/* _SYS_ZAP_H */
508