git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/str_hash.h

   1 #ifndef _BCACHEFS_STR_HASH_H
   2 #define _BCACHEFS_STR_HASH_H
   3
   4 #include "btree_iter.h"
   5 #include "btree_update.h"
   6 #include "checksum.h"
   7 #include "error.h"
   8 #include "inode.h"
   9 #include "siphash.h"
  10 #include "super.h"
  11
  12 #include <linux/crc32c.h>
  13 #include <crypto/hash.h>
  14
  15 struct bch_hash_info {
  16         u8                      type;
  17         union {
  18                 __le64          crc_key;
  19                 SIPHASH_KEY     siphash_key;
  20         };
  21 };
  22
  23 static inline struct bch_hash_info
  24 bch2_hash_info_init(struct bch_fs *c,
  25                    const struct bch_inode_unpacked *bi)
  26 {
  27         /* XXX ick */
  28         struct bch_hash_info info = {
  29                 .type = (bi->bi_flags >> INODE_STR_HASH_OFFSET) &
  30                         ~(~0U << INODE_STR_HASH_BITS)
  31         };
  32
  33         switch (info.type) {
  34         case BCH_STR_HASH_CRC32C:
  35         case BCH_STR_HASH_CRC64:
  36                 info.crc_key = bi->bi_hash_seed;
  37                 break;
  38         case BCH_STR_HASH_SIPHASH: {
  39                 SHASH_DESC_ON_STACK(desc, c->sha256);
  40                 u8 digest[crypto_shash_digestsize(c->sha256)];
  41
  42                 desc->tfm = c->sha256;
  43                 desc->flags = 0;
  44
  45                 crypto_shash_digest(desc, (void *) &bi->bi_hash_seed,
  46                                     sizeof(bi->bi_hash_seed), digest);
  47                 memcpy(&info.siphash_key, digest, sizeof(info.siphash_key));
  48                 break;
  49         }
  50         default:
  51                 BUG();
  52         }
  53
  54         return info;
  55 }
  56
  57 struct bch_str_hash_ctx {
  58         union {
  59                 u32             crc32c;
  60                 u64             crc64;
  61                 SIPHASH_CTX     siphash;
  62         };
  63 };
  64
  65 static inline void bch2_str_hash_init(struct bch_str_hash_ctx *ctx,
  66                                      const struct bch_hash_info *info)
  67 {
  68         switch (info->type) {
  69         case BCH_STR_HASH_CRC32C:
  70                 ctx->crc32c = crc32c(~0, &info->crc_key, sizeof(info->crc_key));
  71                 break;
  72         case BCH_STR_HASH_CRC64:
  73                 ctx->crc64 = bch2_crc64_update(~0, &info->crc_key, sizeof(info->crc_key));
  74                 break;
  75         case BCH_STR_HASH_SIPHASH:
  76                 SipHash24_Init(&ctx->siphash, &info->siphash_key);
  77                 break;
  78         default:
  79                 BUG();
  80         }
  81 }
  82
  83 static inline void bch2_str_hash_update(struct bch_str_hash_ctx *ctx,
  84                                        const struct bch_hash_info *info,
  85                                        const void *data, size_t len)
  86 {
  87         switch (info->type) {
  88         case BCH_STR_HASH_CRC32C:
  89                 ctx->crc32c = crc32c(ctx->crc32c, data, len);
  90                 break;
  91         case BCH_STR_HASH_CRC64:
  92                 ctx->crc64 = bch2_crc64_update(ctx->crc64, data, len);
  93                 break;
  94         case BCH_STR_HASH_SIPHASH:
  95                 SipHash24_Update(&ctx->siphash, data, len);
  96                 break;
  97         default:
  98                 BUG();
  99         }
 100 }
 101
 102 static inline u64 bch2_str_hash_end(struct bch_str_hash_ctx *ctx,
 103                                    const struct bch_hash_info *info)
 104 {
 105         switch (info->type) {
 106         case BCH_STR_HASH_CRC32C:
 107                 return ctx->crc32c;
 108         case BCH_STR_HASH_CRC64:
 109                 return ctx->crc64 >> 1;
 110         case BCH_STR_HASH_SIPHASH:
 111                 return SipHash24_End(&ctx->siphash) >> 1;
 112         default:
 113                 BUG();
 114         }
 115 }
 116
 117 struct bch_hash_desc {
 118         enum btree_id   btree_id;
 119         u8              key_type;
 120
 121         u64             (*hash_key)(const struct bch_hash_info *, const void *);
 122         u64             (*hash_bkey)(const struct bch_hash_info *, struct bkey_s_c);
 123         bool            (*cmp_key)(struct bkey_s_c, const void *);
 124         bool            (*cmp_bkey)(struct bkey_s_c, struct bkey_s_c);
 125 };
 126
 127 static inline struct btree_iter *
 128 bch2_hash_lookup(struct btree_trans *trans,
 129                  const struct bch_hash_desc desc,
 130                  const struct bch_hash_info *info,
 131                  u64 inode, const void *key,
 132                  unsigned flags)
 133 {
 134         struct btree_iter *iter;
 135         struct bkey_s_c k;
 136
 137         iter = bch2_trans_get_iter(trans, desc.btree_id,
 138                                    POS(inode, desc.hash_key(info, key)),
 139                                    BTREE_ITER_SLOTS|flags);
 140         if (IS_ERR(iter))
 141                 return iter;
 142
 143         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 144                 if (iter->pos.inode != inode)
 145                         break;
 146
 147                 if (k.k->type == desc.key_type) {
 148                         if (!desc.cmp_key(k, key))
 149                                 return iter;
 150                 } else if (k.k->type == KEY_TYPE_whiteout) {
 151                         ;
 152                 } else {
 153                         /* hole, not found */
 154                         break;
 155                 }
 156         }
 157
 158         return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOENT);
 159 }
 160
 161 static inline struct btree_iter *
 162 bch2_hash_hole(struct btree_trans *trans,
 163                const struct bch_hash_desc desc,
 164                const struct bch_hash_info *info,
 165                u64 inode, const void *key)
 166 {
 167         struct btree_iter *iter;
 168         struct bkey_s_c k;
 169
 170         iter = bch2_trans_get_iter(trans, desc.btree_id,
 171                                    POS(inode, desc.hash_key(info, key)),
 172                                    BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 173         if (IS_ERR(iter))
 174                 return iter;
 175
 176         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 177                 if (iter->pos.inode != inode)
 178                         break;
 179
 180                 if (k.k->type != desc.key_type)
 181                         return iter;
 182         }
 183
 184         return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOSPC);
 185 }
 186
 187 static inline int bch2_hash_needs_whiteout(struct btree_trans *trans,
 188                                            const struct bch_hash_desc desc,
 189                                            const struct bch_hash_info *info,
 190                                            struct btree_iter *start)
 191 {
 192         struct btree_iter *iter;
 193         struct bkey_s_c k;
 194
 195         iter = bch2_trans_copy_iter(trans, start);
 196         if (IS_ERR(iter))
 197                 return PTR_ERR(iter);
 198
 199         bch2_btree_iter_next_slot(iter);
 200
 201         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 202                 if (k.k->type != desc.key_type &&
 203                     k.k->type != KEY_TYPE_whiteout)
 204                         return false;
 205
 206                 if (k.k->type == desc.key_type &&
 207                     desc.hash_bkey(info, k) <= start->pos.offset)
 208                         return true;
 209         }
 210         return btree_iter_err(k);
 211 }
 212
 213 static inline int __bch2_hash_set(struct btree_trans *trans,
 214                                   const struct bch_hash_desc desc,
 215                                   const struct bch_hash_info *info,
 216                                   u64 inode, struct bkey_i *insert, int flags)
 217 {
 218         struct btree_iter *iter, *slot = NULL;
 219         struct bkey_s_c k;
 220
 221         iter = bch2_trans_get_iter(trans, desc.btree_id,
 222                         POS(inode, desc.hash_bkey(info, bkey_i_to_s_c(insert))),
 223                         BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 224         if (IS_ERR(iter))
 225                 return PTR_ERR(iter);
 226
 227         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 228                 if (iter->pos.inode != inode)
 229                         break;
 230
 231                 if (k.k->type == desc.key_type) {
 232                         if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert)))
 233                                 goto found;
 234
 235                         /* hash collision: */
 236                         continue;
 237                 }
 238
 239                 if (!slot &&
 240                     !(flags & BCH_HASH_SET_MUST_REPLACE)) {
 241                         slot = bch2_trans_copy_iter(trans, iter);
 242                         if (IS_ERR(slot))
 243                                 return PTR_ERR(slot);
 244                 }
 245
 246                 if (k.k->type != KEY_TYPE_whiteout)
 247                         goto not_found;
 248         }
 249
 250         return btree_iter_err(k) ?: -ENOSPC;
 251 not_found:
 252         if (flags & BCH_HASH_SET_MUST_REPLACE)
 253                 return -ENOENT;
 254
 255         insert->k.p = slot->pos;
 256         bch2_trans_update(trans, BTREE_INSERT_ENTRY(slot, insert));
 257         return 0;
 258 found:
 259         if (flags & BCH_HASH_SET_MUST_CREATE)
 260                 return -EEXIST;
 261
 262         insert->k.p = iter->pos;
 263         bch2_trans_update(trans, BTREE_INSERT_ENTRY(iter, insert));
 264         return 0;
 265 }
 266
 267 static inline int bch2_hash_set(const struct bch_hash_desc desc,
 268                                const struct bch_hash_info *info,
 269                                struct bch_fs *c, u64 inode,
 270                                u64 *journal_seq,
 271                                struct bkey_i *insert, int flags)
 272 {
 273         return bch2_trans_do(c, journal_seq, flags|BTREE_INSERT_ATOMIC,
 274                         __bch2_hash_set(&trans, desc, info,
 275                                         inode, insert, flags));
 276 }
 277
 278 static inline int bch2_hash_delete_at(struct btree_trans *trans,
 279                                       const struct bch_hash_desc desc,
 280                                       const struct bch_hash_info *info,
 281                                       struct btree_iter *iter)
 282 {
 283         struct bkey_i *delete;
 284         int ret;
 285
 286         ret = bch2_hash_needs_whiteout(trans, desc, info, iter);
 287         if (ret < 0)
 288                 return ret;
 289
 290         delete = bch2_trans_kmalloc(trans, sizeof(*delete));
 291         if (IS_ERR(delete))
 292                 return PTR_ERR(delete);
 293
 294         bkey_init(&delete->k);
 295         delete->k.p = iter->pos;
 296         delete->k.type = ret ? KEY_TYPE_whiteout : KEY_TYPE_deleted;
 297
 298         bch2_trans_update(trans, BTREE_INSERT_ENTRY(iter, delete));
 299         return 0;
 300 }
 301
 302 static inline int bch2_hash_delete(struct btree_trans *trans,
 303                                    const struct bch_hash_desc desc,
 304                                    const struct bch_hash_info *info,
 305                                    u64 inode, const void *key)
 306 {
 307         struct btree_iter *iter;
 308
 309         iter = bch2_hash_lookup(trans, desc, info, inode, key,
 310                                 BTREE_ITER_INTENT);
 311         if (IS_ERR(iter))
 312                 return PTR_ERR(iter);
 313
 314         return bch2_hash_delete_at(trans, desc, info, iter);
 315 }
 316
 317 #endif /* _BCACHEFS_STR_HASH_H */