module/zfs/include/sys/zap_leaf.h

   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 union zap_leaf_chunk {
 131         struct zap_leaf_entry {
 132                 uint8_t le_type;                /* always ZAP_CHUNK_ENTRY */
 133                 uint8_t le_value_intlen;        /* size of value's ints */
 134                 uint16_t le_next;               /* next entry in hash chain */
 135                 uint16_t le_name_chunk;         /* first chunk of the name */
 136                 uint16_t le_name_numints;       /* ints in name (incl null) */
 137                 uint16_t le_value_chunk;        /* first chunk of the value */
 138                 uint16_t le_value_numints;      /* value length in ints */
 139                 uint32_t le_cd;                 /* collision differentiator */
 140                 uint64_t le_hash;               /* hash value of the name */
 141         } l_entry;
 142         struct zap_leaf_array {
 143                 uint8_t la_type;                /* always ZAP_CHUNK_ARRAY */
 144                 uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
 145                 uint16_t la_next;               /* next blk or CHAIN_END */
 146         } l_array;
 147         struct zap_leaf_free {
 148                 uint8_t lf_type;                /* always ZAP_CHUNK_FREE */
 149                 uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
 150                 uint16_t lf_next;       /* next in free list, or CHAIN_END */
 151         } l_free;
 152 } zap_leaf_chunk_t;
 153
 154 typedef struct zap_leaf {
 155         krwlock_t l_rwlock;
 156         uint64_t l_blkid;               /* 1<<ZAP_BLOCK_SHIFT byte block off */
 157         int l_bs;                       /* block size shift */
 158         dmu_buf_t *l_dbuf;
 159         zap_leaf_phys_t *l_phys;
 160 } zap_leaf_t;
 161
 162
 163 typedef struct zap_entry_handle {
 164         /* below is set by zap_leaf.c and is public to zap.c */
 165         uint64_t zeh_num_integers;
 166         uint64_t zeh_hash;
 167         uint32_t zeh_cd;
 168         uint8_t zeh_integer_size;
 169
 170         /* below is private to zap_leaf.c */
 171         uint16_t zeh_fakechunk;
 172         uint16_t *zeh_chunkp;
 173         zap_leaf_t *zeh_leaf;
 174 } zap_entry_handle_t;
 175
 176 /*
 177  * Return a handle to the named entry, or ENOENT if not found.  The hash
 178  * value must equal zap_hash(name).
 179  */
 180 extern int zap_leaf_lookup(zap_leaf_t *l,
 181     struct zap_name *zn, zap_entry_handle_t *zeh);
 182
 183 /*
 184  * Return a handle to the entry with this hash+cd, or the entry with the
 185  * next closest hash+cd.
 186  */
 187 extern int zap_leaf_lookup_closest(zap_leaf_t *l,
 188     uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh);
 189
 190 /*
 191  * Read the first num_integers in the attribute.  Integer size
 192  * conversion will be done without sign extension.  Return EINVAL if
 193  * integer_size is too small.  Return EOVERFLOW if there are more than
 194  * num_integers in the attribute.
 195  */
 196 extern int zap_entry_read(const zap_entry_handle_t *zeh,
 197     uint8_t integer_size, uint64_t num_integers, void *buf);
 198
 199 extern int zap_entry_read_name(struct zap *zap, const zap_entry_handle_t *zeh,
 200     uint16_t buflen, char *buf);
 201
 202 /*
 203  * Replace the value of an existing entry.
 204  *
 205  * zap_entry_update may fail if it runs out of space (ENOSPC).
 206  */
 207 extern int zap_entry_update(zap_entry_handle_t *zeh,
 208     uint8_t integer_size, uint64_t num_integers, const void *buf);
 209
 210 /*
 211  * Remove an entry.
 212  */
 213 extern void zap_entry_remove(zap_entry_handle_t *zeh);
 214
 215 /*
 216  * Create an entry. An equal entry must not exist, and this entry must
 217  * belong in this leaf (according to its hash value).  Fills in the
 218  * entry handle on success.  Returns 0 on success or ENOSPC on failure.
 219  */
 220 extern int zap_entry_create(zap_leaf_t *l, struct zap_name *zn, uint32_t cd,
 221     uint8_t integer_size, uint64_t num_integers, const void *buf,
 222     zap_entry_handle_t *zeh);
 223
 224 /*
 225  * Return true if there are additional entries with the same normalized
 226  * form.
 227  */
 228 extern boolean_t zap_entry_normalization_conflict(zap_entry_handle_t *zeh,
 229     struct zap_name *zn, const char *name, struct zap *zap);
 230
 231 /*
 232  * Other stuff.
 233  */
 234
 235 extern void zap_leaf_init(zap_leaf_t *l, boolean_t sort);
 236 extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len);
 237 extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort);
 238 extern void zap_leaf_stats(struct zap *zap, zap_leaf_t *l,
 239     struct zap_stats *zs);
 240
 241 #ifdef  __cplusplus
 242 }
 243 #endif
 244
 245 #endif /* _SYS_ZAP_LEAF_H */