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 2006 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #ifndef _SYS_ZAP_LEAF_H 27 #define _SYS_ZAP_LEAF_H 28 29 #pragma ident "%Z%%M% %I% %E% SMI" 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 struct zap; 36 37 #define ZAP_LEAF_MAGIC 0x2AB1EAF 38 39 /* chunk size = 24 bytes */ 40 #define ZAP_LEAF_CHUNKSIZE 24 41 42 /* 43 * The amount of space available for chunks is: 44 * block size (1<<l->l_bs) - hash entry size (2) * number of hash 45 * entries - header space (2*chunksize) 46 */ 47 #define ZAP_LEAF_NUMCHUNKS(l) \ 48 (((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \ 49 ZAP_LEAF_CHUNKSIZE - 2) 50 51 /* 52 * The amount of space within the chunk available for the array is: 53 * chunk size - space for type (1) - space for next pointer (2) 54 */ 55 #define ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3) 56 57 #define ZAP_LEAF_ARRAY_NCHUNKS(bytes) \ 58 (((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES) 59 60 /* 61 * Low water mark: when there are only this many chunks free, start 62 * growing the ptrtbl. Ideally, this should be larger than a 63 * "reasonably-sized" entry. 20 chunks is more than enough for the 64 * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value), 65 * while still being only around 3% for 16k blocks. 66 */ 67 #define ZAP_LEAF_LOW_WATER (20) 68 69 /* 70 * The leaf hash table has block size / 2^5 (32) number of entries, 71 * which should be more than enough for the maximum number of entries, 72 * which is less than block size / CHUNKSIZE (24) / minimum number of 73 * chunks per entry (3). 74 */ 75 #define ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5) 76 #define ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l)) 77 78 /* 79 * The chunks start immediately after the hash table. The end of the 80 * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a 81 * chunk_t. 82 */ 83 #define ZAP_LEAF_CHUNK(l, idx) \ 84 ((zap_leaf_chunk_t *) \ 85 ((l)->l_phys->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx] 86 #define ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry) 87 88 typedef enum zap_chunk_type { 89 ZAP_CHUNK_FREE = 253, 90 ZAP_CHUNK_ENTRY = 252, 91 ZAP_CHUNK_ARRAY = 251, 92 ZAP_CHUNK_TYPE_MAX = 250 93 } zap_chunk_type_t; 94 95 /* 96 * TAKE NOTE: 97 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified. 98 */ 99 typedef struct zap_leaf_phys { 100 struct zap_leaf_header { 101 uint64_t lh_block_type; /* ZBT_LEAF */ 102 uint64_t lh_pad1; 103 uint64_t lh_prefix; /* hash prefix of this leaf */ 104 uint32_t lh_magic; /* ZAP_LEAF_MAGIC */ 105 uint16_t lh_nfree; /* number free chunks */ 106 uint16_t lh_nentries; /* number of entries */ 107 uint16_t lh_prefix_len; /* num bits used to id this */ 108 109 /* above is accessable to zap, below is zap_leaf private */ 110 111 uint16_t lh_freelist; /* chunk head of free list */ 112 uint8_t lh_pad2[12]; 113 } l_hdr; /* 2 24-byte chunks */ 114 115 /* 116 * The header is followed by a hash table with 117 * ZAP_LEAF_HASH_NUMENTRIES(zap) entries. The hash table is 118 * followed by an array of ZAP_LEAF_NUMCHUNKS(zap) 119 * zap_leaf_chunk structures. These structures are accessed 120 * with the ZAP_LEAF_CHUNK() macro. 121 */ 122 123 uint16_t l_hash[1]; 124 } zap_leaf_phys_t; 125 126 typedef union zap_leaf_chunk { 127 struct zap_leaf_entry { 128 uint8_t le_type; /* always ZAP_CHUNK_ENTRY */ 129 uint8_t le_int_size; /* size of ints */ 130 uint16_t le_next; /* next entry in hash chain */ 131 uint16_t le_name_chunk; /* first chunk of the name */ 132 uint16_t le_name_length; /* bytes in name, incl null */ 133 uint16_t le_value_chunk; /* first chunk of the value */ 134 uint16_t le_value_length; /* value length in ints */ 135 uint32_t le_cd; /* collision differentiator */ 136 uint64_t le_hash; /* hash value of the name */ 137 } l_entry; 138 struct zap_leaf_array { 139 uint8_t la_type; /* always ZAP_CHUNK_ARRAY */ 140 uint8_t la_array[ZAP_LEAF_ARRAY_BYTES]; 141 uint16_t la_next; /* next blk or CHAIN_END */ 142 } l_array; 143 struct zap_leaf_free { 144 uint8_t lf_type; /* always ZAP_CHUNK_FREE */ 145 uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES]; 146 uint16_t lf_next; /* next in free list, or CHAIN_END */ 147 } l_free; 148 } zap_leaf_chunk_t; 149 150 typedef struct zap_leaf { 151 krwlock_t l_rwlock; /* only used on head of chain */ 152 uint64_t l_blkid; /* 1<<ZAP_BLOCK_SHIFT byte block off */ 153 int l_bs; /* block size shift */ 154 dmu_buf_t *l_dbuf; 155 zap_leaf_phys_t *l_phys; 156 } zap_leaf_t; 157 158 159 typedef struct zap_entry_handle { 160 /* below is set by zap_leaf.c and is public to zap.c */ 161 uint64_t zeh_num_integers; 162 uint64_t zeh_hash; 163 uint32_t zeh_cd; 164 uint8_t zeh_integer_size; 165 166 /* below is private to zap_leaf.c */ 167 uint16_t zeh_fakechunk; 168 uint16_t *zeh_chunkp; 169 zap_leaf_t *zeh_leaf; 170 } zap_entry_handle_t; 171 172 /* 173 * Return a handle to the named entry, or ENOENT if not found. The hash 174 * value must equal zap_hash(name). 175 */ 176 extern int zap_leaf_lookup(zap_leaf_t *l, 177 const char *name, uint64_t h, zap_entry_handle_t *zeh); 178 179 /* 180 * Return a handle to the entry with this hash+cd, or the entry with the 181 * next closest hash+cd. 182 */ 183 extern int zap_leaf_lookup_closest(zap_leaf_t *l, 184 uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh); 185 186 /* 187 * Read the first num_integers in the attribute. Integer size 188 * conversion will be done without sign extension. Return EINVAL if 189 * integer_size is too small. Return EOVERFLOW if there are more than 190 * num_integers in the attribute. 191 */ 192 extern int zap_entry_read(const zap_entry_handle_t *zeh, 193 uint8_t integer_size, uint64_t num_integers, void *buf); 194 195 extern int zap_entry_read_name(const zap_entry_handle_t *zeh, 196 uint16_t buflen, char *buf); 197 198 /* 199 * Replace the value of an existing entry. 200 * 201 * zap_entry_update may fail if it runs out of space (ENOSPC). 202 */ 203 extern int zap_entry_update(zap_entry_handle_t *zeh, 204 uint8_t integer_size, uint64_t num_integers, const void *buf); 205 206 /* 207 * Remove an entry. 208 */ 209 extern void zap_entry_remove(zap_entry_handle_t *zeh); 210 211 /* 212 * Create an entry. An equal entry must not exist, and this entry must 213 * belong in this leaf (according to its hash value). Fills in the 214 * entry handle on success. Returns 0 on success or ENOSPC on failure. 215 */ 216 extern int zap_entry_create(zap_leaf_t *l, 217 const char *name, uint64_t h, uint32_t cd, 218 uint8_t integer_size, uint64_t num_integers, const void *buf, 219 zap_entry_handle_t *zeh); 220 221 /* 222 * Other stuff. 223 */ 224 225 extern void zap_leaf_init(zap_leaf_t *l); 226 extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len); 227 extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl); 228 extern void zap_leaf_stats(zap_t *zap, zap_leaf_t *l, zap_stats_t *zs); 229 230 #ifdef __cplusplus 231 } 232 #endif 233 234 #endif /* _SYS_ZAP_LEAF_H */ 235