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_LEAF_H
26 #define _SYS_ZAP_LEAF_H
27
28 #include <sys/zap.h>
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
34 struct zap;
35 struct zap_name;
36 struct zap_stats;
37
38 #define ZAP_LEAF_MAGIC 0x2AB1EAF
39
40 /* chunk size = 24 bytes */
41 #define ZAP_LEAF_CHUNKSIZE 24
42
43 /*
44 * The amount of space available for chunks is:
45 * block size (1<<l->l_bs) - hash entry size (2) * number of hash
46 * entries - header space (2*chunksize)
47 */
48 #define ZAP_LEAF_NUMCHUNKS(l) \
49 (((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \
50 ZAP_LEAF_CHUNKSIZE - 2)
51
52 /*
53 * The amount of space within the chunk available for the array is:
54 * chunk size - space for type (1) - space for next pointer (2)
55 */
56 #define ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)
57
58 #define ZAP_LEAF_ARRAY_NCHUNKS(bytes) \
59 (((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES)
60
61 /*
62 * Low water mark: when there are only this many chunks free, start
63 * growing the ptrtbl. Ideally, this should be larger than a
64 * "reasonably-sized" entry. 20 chunks is more than enough for the
65 * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value),
66 * while still being only around 3% for 16k blocks.
67 */
68 #define ZAP_LEAF_LOW_WATER (20)
69
70 /*
71 * The leaf hash table has block size / 2^5 (32) number of entries,
72 * which should be more than enough for the maximum number of entries,
73 * which is less than block size / CHUNKSIZE (24) / minimum number of
74 * chunks per entry (3).
75 */
76 #define ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5)
77 #define ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l))
78
79 /*
80 * The chunks start immediately after the hash table. The end of the
81 * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a
82 * chunk_t.
83 */
84 #define ZAP_LEAF_CHUNK(l, idx) \
85 ((zap_leaf_chunk_t *) \
86 ((l)->l_phys->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx]
87 #define ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry)
88
89 typedef enum zap_chunk_type {
90 ZAP_CHUNK_FREE = 253,
91 ZAP_CHUNK_ENTRY = 252,
92 ZAP_CHUNK_ARRAY = 251,
93 ZAP_CHUNK_TYPE_MAX = 250
94 } zap_chunk_type_t;
95
96 #define ZLF_ENTRIES_CDSORTED (1<<0)
97
98 /*
99 * TAKE NOTE:
100 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
101 */
102 typedef struct zap_leaf_phys {
103 struct zap_leaf_header {
104 uint64_t lh_block_type; /* ZBT_LEAF */
105 uint64_t lh_pad1;
106 uint64_t lh_prefix; /* hash prefix of this leaf */
107 uint32_t lh_magic; /* ZAP_LEAF_MAGIC */
108 uint16_t lh_nfree; /* number free chunks */
109 uint16_t lh_nentries; /* number of entries */
110 uint16_t lh_prefix_len; /* num bits used to id this */
111
112 /* above is accessable to zap, below is zap_leaf private */
113
114 uint16_t lh_freelist; /* chunk head of free list */
115 uint8_t lh_flags; /* ZLF_* flags */
116 uint8_t lh_pad2[11];
117 } l_hdr; /* 2 24-byte chunks */
118
119 /*
120 * The header is followed by a hash table with
121 * ZAP_LEAF_HASH_NUMENTRIES(zap) entries. The hash table is
122 * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
123 * zap_leaf_chunk structures. These structures are accessed
124 * with the ZAP_LEAF_CHUNK() macro.
125 */
126
127 uint16_t l_hash[1];
128 } zap_leaf_phys_t;
129
130 typedef struct zap_leaf_dbuf {
131 uint8_t zldb_pad[offsetof(dmu_buf_t, db_data)];
132 zap_leaf_phys_t *zldb_data;
133 } zap_leaf_dbuf_t;
134
135 typedef union zap_leaf_chunk {
136 struct zap_leaf_entry {
137 uint8_t le_type; /* always ZAP_CHUNK_ENTRY */
138 uint8_t le_value_intlen; /* size of value's ints */
139 uint16_t le_next; /* next entry in hash chain */
140 uint16_t le_name_chunk; /* first chunk of the name */
141 uint16_t le_name_numints; /* ints in name (incl null) */
142 uint16_t le_value_chunk; /* first chunk of the value */
143 uint16_t le_value_numints; /* value length in ints */
144 uint32_t le_cd; /* collision differentiator */
145 uint64_t le_hash; /* hash value of the name */
146 } l_entry;
147 struct zap_leaf_array {
148 uint8_t la_type; /* always ZAP_CHUNK_ARRAY */
149 uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
150 uint16_t la_next; /* next blk or CHAIN_END */
151 } l_array;
152 struct zap_leaf_free {
153 uint8_t lf_type; /* always ZAP_CHUNK_FREE */
154 uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
155 uint16_t lf_next; /* next in free list, or CHAIN_END */
156 } l_free;
157 } zap_leaf_chunk_t;
158
159 typedef struct zap_leaf {
160 dmu_buf_user_t db_evict;
161 krwlock_t l_rwlock;
162 uint64_t l_blkid; /* 1<<ZAP_BLOCK_SHIFT byte block off */
163 int l_bs; /* block size shift */
164 union {
165 dmu_buf_t *l_dmu_db;
166 zap_leaf_dbuf_t *l_db;
167 } zl_db_u;
168 } zap_leaf_t;
169
170 #define l_dbuf zl_db_u.l_dmu_db
171 #define l_phys zl_db_u.l_db->zldb_data
172
173 typedef struct zap_entry_handle {
174 /* below is set by zap_leaf.c and is public to zap.c */
175 uint64_t zeh_num_integers;
176 uint64_t zeh_hash;
177 uint32_t zeh_cd;
178 uint8_t zeh_integer_size;
179
180 /* below is private to zap_leaf.c */
181 uint16_t zeh_fakechunk;
182 uint16_t *zeh_chunkp;
183 zap_leaf_t *zeh_leaf;
184 } zap_entry_handle_t;
185
186 /*
187 * Return a handle to the named entry, or ENOENT if not found. The hash
188 * value must equal zap_hash(name).
189 */
190 extern int zap_leaf_lookup(zap_leaf_t *l,
191 struct zap_name *zn, zap_entry_handle_t *zeh);
192
193 /*
194 * Return a handle to the entry with this hash+cd, or the entry with the
195 * next closest hash+cd.
196 */
197 extern int zap_leaf_lookup_closest(zap_leaf_t *l,
198 uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh);
199
200 /*
201 * Read the first num_integers in the attribute. Integer size
202 * conversion will be done without sign extension. Return EINVAL if
203 * integer_size is too small. Return EOVERFLOW if there are more than
204 * num_integers in the attribute.
205 */
206 extern int zap_entry_read(const zap_entry_handle_t *zeh,
207 uint8_t integer_size, uint64_t num_integers, void *buf);
208
209 extern int zap_entry_read_name(struct zap *zap, const zap_entry_handle_t *zeh,
210 uint16_t buflen, char *buf);
211
212 /*
213 * Replace the value of an existing entry.
214 *
215 * zap_entry_update may fail if it runs out of space (ENOSPC).
216 */
217 extern int zap_entry_update(zap_entry_handle_t *zeh,
218 uint8_t integer_size, uint64_t num_integers, const void *buf);
219
220 /*
221 * Remove an entry.
222 */
223 extern void zap_entry_remove(zap_entry_handle_t *zeh);
224
225 /*
226 * Create an entry. An equal entry must not exist, and this entry must
227 * belong in this leaf (according to its hash value). Fills in the
228 * entry handle on success. Returns 0 on success or ENOSPC on failure.
229 */
230 extern int zap_entry_create(zap_leaf_t *l, struct zap_name *zn, uint32_t cd,
231 uint8_t integer_size, uint64_t num_integers, const void *buf,
232 zap_entry_handle_t *zeh);
233
234 /*
235 * Return true if there are additional entries with the same normalized
236 * form.
237 */
238 extern boolean_t zap_entry_normalization_conflict(zap_entry_handle_t *zeh,
239 struct zap_name *zn, const char *name, struct zap *zap);
240
241 /*
242 * Other stuff.
243 */
244
245 extern void zap_leaf_init(zap_leaf_t *l, boolean_t sort);
246 extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len);
247 extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort);
248 extern void zap_leaf_stats(struct zap *zap, zap_leaf_t *l,
249 struct zap_stats *zs);
250
251 #ifdef __cplusplus
252 }
253 #endif
254
255 #endif /* _SYS_ZAP_LEAF_H */