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) 2014 Spectra Logic Corporation, All rights reserved.
24 */
25
26 #ifndef _SYS_ZAP_LEAF_H
27 #define _SYS_ZAP_LEAF_H
28
29 #include <sys/zap.h>
30
31 #ifdef __cplusplus
32 extern "C" {
33 #endif
34
35 struct zap;
36 struct zap_name;
37 struct zap_stats;
38
39 #define ZAP_LEAF_MAGIC 0x2AB1EAF
40
41 /* chunk size = 24 bytes */
42 #define ZAP_LEAF_CHUNKSIZE 24
43
44 /*
45 * The amount of space available for chunks is:
46 * block size (1<<l->l_bs) - hash entry size (2) * number of hash
47 * entries - header space (2*chunksize)
48 */
49 #define ZAP_LEAF_NUMCHUNKS(l) \
50 (((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \
51 ZAP_LEAF_CHUNKSIZE - 2)
52
53 /*
54 * The amount of space within the chunk available for the array is:
55 * chunk size - space for type (1) - space for next pointer (2)
56 */
57 #define ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)
58
59 #define ZAP_LEAF_ARRAY_NCHUNKS(bytes) \
60 (((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES)
61
62 /*
63 * Low water mark: when there are only this many chunks free, start
64 * growing the ptrtbl. Ideally, this should be larger than a
65 * "reasonably-sized" entry. 20 chunks is more than enough for the
66 * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value),
67 * while still being only around 3% for 16k blocks.
68 */
69 #define ZAP_LEAF_LOW_WATER (20)
70
71 /*
72 * The leaf hash table has block size / 2^5 (32) number of entries,
73 * which should be more than enough for the maximum number of entries,
74 * which is less than block size / CHUNKSIZE (24) / minimum number of
75 * chunks per entry (3).
76 */
77 #define ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5)
78 #define ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l))
79
80 /*
81 * The chunks start immediately after the hash table. The end of the
82 * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a
83 * chunk_t.
84 */
85 #define ZAP_LEAF_CHUNK(l, idx) \
86 ((zap_leaf_chunk_t *) \
87 (zap_leaf_phys(l)->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx]
88 #define ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry)
89
90 typedef enum zap_chunk_type {
91 ZAP_CHUNK_FREE = 253,
92 ZAP_CHUNK_ENTRY = 252,
93 ZAP_CHUNK_ARRAY = 251,
94 ZAP_CHUNK_TYPE_MAX = 250
95 } zap_chunk_type_t;
96
97 #define ZLF_ENTRIES_CDSORTED (1<<0)
98
99 /*
100 * TAKE NOTE:
101 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
102 */
103 typedef struct zap_leaf_phys {
104 struct zap_leaf_header {
105 /* Public to ZAP */
106 uint64_t lh_block_type; /* ZBT_LEAF */
107 uint64_t lh_pad1;
108 uint64_t lh_prefix; /* hash prefix of this leaf */
109 uint32_t lh_magic; /* ZAP_LEAF_MAGIC */
110 uint16_t lh_nfree; /* number free chunks */
111 uint16_t lh_nentries; /* number of entries */
112 uint16_t lh_prefix_len; /* num bits used to id this */
113
114 /* Private to zap_leaf */
115 uint16_t lh_freelist; /* chunk head of free list */
116 uint8_t lh_flags; /* ZLF_* flags */
117 uint8_t lh_pad2[11];
118 } l_hdr; /* 2 24-byte chunks */
119
120 /*
121 * The header is followed by a hash table with
122 * ZAP_LEAF_HASH_NUMENTRIES(zap) entries. The hash table is
123 * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
124 * zap_leaf_chunk structures. These structures are accessed
125 * with the ZAP_LEAF_CHUNK() macro.
126 */
127
128 uint16_t l_hash[1];
129 } zap_leaf_phys_t;
130
131 typedef union zap_leaf_chunk {
132 struct zap_leaf_entry {
133 uint8_t le_type; /* always ZAP_CHUNK_ENTRY */
134 uint8_t le_value_intlen; /* size of value's ints */
135 uint16_t le_next; /* next entry in hash chain */
136 uint16_t le_name_chunk; /* first chunk of the name */
137 uint16_t le_name_numints; /* ints in name (incl null) */
138 uint16_t le_value_chunk; /* first chunk of the value */
139 uint16_t le_value_numints; /* value length in ints */
140 uint32_t le_cd; /* collision differentiator */
141 uint64_t le_hash; /* hash value of the name */
142 } l_entry;
143 struct zap_leaf_array {
144 uint8_t la_type; /* always ZAP_CHUNK_ARRAY */
145 uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
146 uint16_t la_next; /* next blk or CHAIN_END */
147 } l_array;
148 struct zap_leaf_free {
149 uint8_t lf_type; /* always ZAP_CHUNK_FREE */
150 uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
151 uint16_t lf_next; /* next in free list, or CHAIN_END */
152 } l_free;
153 } zap_leaf_chunk_t;
154
155 typedef struct zap_leaf {
156 dmu_buf_user_t l_dbu;
157 krwlock_t l_rwlock;
158 uint64_t l_blkid; /* 1<<ZAP_BLOCK_SHIFT byte block off */
159 int l_bs; /* block size shift */
160 dmu_buf_t *l_dbuf;
161 } zap_leaf_t;
162
163 inline zap_leaf_phys_t *
zap_leaf_phys(zap_leaf_t * l)164 zap_leaf_phys(zap_leaf_t *l)
165 {
166 return (l->l_dbuf->db_data);
167 }
168
169 typedef struct zap_entry_handle {
170 /* Set by zap_leaf and public to ZAP */
171 uint64_t zeh_num_integers;
172 uint64_t zeh_hash;
173 uint32_t zeh_cd;
174 uint8_t zeh_integer_size;
175
176 /* Private to zap_leaf */
177 uint16_t zeh_fakechunk;
178 uint16_t *zeh_chunkp;
179 zap_leaf_t *zeh_leaf;
180 } zap_entry_handle_t;
181
182 /*
183 * Return a handle to the named entry, or ENOENT if not found. The hash
184 * value must equal zap_hash(name).
185 */
186 extern int zap_leaf_lookup(zap_leaf_t *l,
187 struct zap_name *zn, zap_entry_handle_t *zeh);
188
189 /*
190 * Return a handle to the entry with this hash+cd, or the entry with the
191 * next closest hash+cd.
192 */
193 extern int zap_leaf_lookup_closest(zap_leaf_t *l,
194 uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh);
195
196 /*
197 * Read the first num_integers in the attribute. Integer size
198 * conversion will be done without sign extension. Return EINVAL if
199 * integer_size is too small. Return EOVERFLOW if there are more than
200 * num_integers in the attribute.
201 */
202 extern int zap_entry_read(const zap_entry_handle_t *zeh,
203 uint8_t integer_size, uint64_t num_integers, void *buf);
204
205 extern int zap_entry_read_name(struct zap *zap, const zap_entry_handle_t *zeh,
206 uint16_t buflen, char *buf);
207
208 /*
209 * Replace the value of an existing entry.
210 *
211 * May fail if it runs out of space (ENOSPC).
212 */
213 extern int zap_entry_update(zap_entry_handle_t *zeh,
214 uint8_t integer_size, uint64_t num_integers, const void *buf);
215
216 /*
217 * Remove an entry.
218 */
219 extern void zap_entry_remove(zap_entry_handle_t *zeh);
220
221 /*
222 * Create an entry. An equal entry must not exist, and this entry must
223 * belong in this leaf (according to its hash value). Fills in the
224 * entry handle on success. Returns 0 on success or ENOSPC on failure.
225 */
226 extern int zap_entry_create(zap_leaf_t *l, struct zap_name *zn, uint32_t cd,
227 uint8_t integer_size, uint64_t num_integers, const void *buf,
228 zap_entry_handle_t *zeh);
229
230 /* Determine whether there is another entry with the same normalized form. */
231 extern boolean_t zap_entry_normalization_conflict(zap_entry_handle_t *zeh,
232 struct zap_name *zn, const char *name, struct zap *zap);
233
234 /*
235 * Other stuff.
236 */
237
238 extern void zap_leaf_init(zap_leaf_t *l, boolean_t sort);
239 extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len);
240 extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort);
241 extern void zap_leaf_stats(struct zap *zap, zap_leaf_t *l,
242 struct zap_stats *zs);
243
244 #ifdef __cplusplus
245 }
246 #endif
247
248 #endif /* _SYS_ZAP_LEAF_H */
249