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 #include <crypto/sha.h>
  15
  16 struct bch_hash_info {
  17         u8                      type;
  18         union {
  19                 __le64          crc_key;
  20                 SIPHASH_KEY     siphash_key;
  21         };
  22 };
  23
  24 static inline struct bch_hash_info
  25 bch2_hash_info_init(struct bch_fs *c,
  26                    const struct bch_inode_unpacked *bi)
  27 {
  28         /* XXX ick */
  29         struct bch_hash_info info = {
  30                 .type = (bi->bi_flags >> INODE_STR_HASH_OFFSET) &
  31                         ~(~0U << INODE_STR_HASH_BITS)
  32         };
  33
  34         switch (info.type) {
  35         case BCH_STR_HASH_CRC32C:
  36         case BCH_STR_HASH_CRC64:
  37                 info.crc_key = bi->bi_hash_seed;
  38                 break;
  39         case BCH_STR_HASH_SIPHASH: {
  40                 SHASH_DESC_ON_STACK(desc, c->sha256);
  41                 u8 digest[SHA256_DIGEST_SIZE];
  42
  43                 desc->tfm = c->sha256;
  44                 desc->flags = 0;
  45
  46                 crypto_shash_digest(desc, (void *) &bi->bi_hash_seed,
  47                                     sizeof(bi->bi_hash_seed), digest);
  48                 memcpy(&info.siphash_key, digest, sizeof(info.siphash_key));
  49                 break;
  50         }
  51         default:
  52                 BUG();
  53         }
  54
  55         return info;
  56 }
  57
  58 struct bch_str_hash_ctx {
  59         union {
  60                 u32             crc32c;
  61                 u64             crc64;
  62                 SIPHASH_CTX     siphash;
  63         };
  64 };
  65
  66 static inline void bch2_str_hash_init(struct bch_str_hash_ctx *ctx,
  67                                      const struct bch_hash_info *info)
  68 {
  69         switch (info->type) {
  70         case BCH_STR_HASH_CRC32C:
  71                 ctx->crc32c = crc32c(~0, &info->crc_key, sizeof(info->crc_key));
  72                 break;
  73         case BCH_STR_HASH_CRC64:
  74                 ctx->crc64 = bch2_crc64_update(~0, &info->crc_key, sizeof(info->crc_key));
  75                 break;
  76         case BCH_STR_HASH_SIPHASH:
  77                 SipHash24_Init(&ctx->siphash, &info->siphash_key);
  78                 break;
  79         default:
  80                 BUG();
  81         }
  82 }
  83
  84 static inline void bch2_str_hash_update(struct bch_str_hash_ctx *ctx,
  85                                        const struct bch_hash_info *info,
  86                                        const void *data, size_t len)
  87 {
  88         switch (info->type) {
  89         case BCH_STR_HASH_CRC32C:
  90                 ctx->crc32c = crc32c(ctx->crc32c, data, len);
  91                 break;
  92         case BCH_STR_HASH_CRC64:
  93                 ctx->crc64 = bch2_crc64_update(ctx->crc64, data, len);
  94                 break;
  95         case BCH_STR_HASH_SIPHASH:
  96                 SipHash24_Update(&ctx->siphash, data, len);
  97                 break;
  98         default:
  99                 BUG();
 100         }
 101 }
 102
 103 static inline u64 bch2_str_hash_end(struct bch_str_hash_ctx *ctx,
 104                                    const struct bch_hash_info *info)
 105 {
 106         switch (info->type) {
 107         case BCH_STR_HASH_CRC32C:
 108                 return ctx->crc32c;
 109         case BCH_STR_HASH_CRC64:
 110                 return ctx->crc64 >> 1;
 111         case BCH_STR_HASH_SIPHASH:
 112                 return SipHash24_End(&ctx->siphash) >> 1;
 113         default:
 114                 BUG();
 115         }
 116 }
 117
 118 struct bch_hash_desc {
 119         enum btree_id   btree_id;
 120         u8              key_type;
 121
 122         u64             (*hash_key)(const struct bch_hash_info *, const void *);
 123         u64             (*hash_bkey)(const struct bch_hash_info *, struct bkey_s_c);
 124         bool            (*cmp_key)(struct bkey_s_c, const void *);
 125         bool            (*cmp_bkey)(struct bkey_s_c, struct bkey_s_c);
 126 };
 127
 128 static __always_inline struct btree_iter *
 129 bch2_hash_lookup(struct btree_trans *trans,
 130                  const struct bch_hash_desc desc,
 131                  const struct bch_hash_info *info,
 132                  u64 inode, const void *key,
 133                  unsigned flags)
 134 {
 135         struct btree_iter *iter;
 136         struct bkey_s_c k;
 137
 138         iter = bch2_trans_get_iter(trans, desc.btree_id,
 139                                    POS(inode, desc.hash_key(info, key)),
 140                                    BTREE_ITER_SLOTS|flags);
 141         if (IS_ERR(iter))
 142                 return iter;
 143
 144         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 145                 if (iter->pos.inode != inode)
 146                         break;
 147
 148                 if (k.k->type == desc.key_type) {
 149                         if (!desc.cmp_key(k, key))
 150                                 return iter;
 151                 } else if (k.k->type == KEY_TYPE_whiteout) {
 152                         ;
 153                 } else {
 154                         /* hole, not found */
 155                         break;
 156                 }
 157         }
 158
 159         return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOENT);
 160 }
 161
 162 static __always_inline struct btree_iter *
 163 bch2_hash_hole(struct btree_trans *trans,
 164                const struct bch_hash_desc desc,
 165                const struct bch_hash_info *info,
 166                u64 inode, const void *key)
 167 {
 168         struct btree_iter *iter;
 169         struct bkey_s_c k;
 170
 171         iter = bch2_trans_get_iter(trans, desc.btree_id,
 172                                    POS(inode, desc.hash_key(info, key)),
 173                                    BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 174         if (IS_ERR(iter))
 175                 return iter;
 176
 177         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 178                 if (iter->pos.inode != inode)
 179                         break;
 180
 181                 if (k.k->type != desc.key_type)
 182                         return iter;
 183         }
 184
 185         return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOSPC);
 186 }
 187
 188 static __always_inline
 189 int bch2_hash_needs_whiteout(struct btree_trans *trans,
 190                              const struct bch_hash_desc desc,
 191                              const struct bch_hash_info *info,
 192                              struct btree_iter *start)
 193 {
 194         struct btree_iter *iter;
 195         struct bkey_s_c k;
 196
 197         iter = bch2_trans_copy_iter(trans, start);
 198         if (IS_ERR(iter))
 199                 return PTR_ERR(iter);
 200
 201         bch2_btree_iter_next_slot(iter);
 202
 203         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 204                 if (k.k->type != desc.key_type &&
 205                     k.k->type != KEY_TYPE_whiteout)
 206                         break;
 207
 208                 if (k.k->type == desc.key_type &&
 209                     desc.hash_bkey(info, k) <= start->pos.offset) {
 210                         bch2_trans_iter_free_on_commit(trans, iter);
 211                         return 1;
 212                 }
 213         }
 214
 215         return bch2_trans_iter_free(trans, iter);
 216 }
 217
 218 static __always_inline
 219 int bch2_hash_set(struct btree_trans *trans,
 220                   const struct bch_hash_desc desc,
 221                   const struct bch_hash_info *info,
 222                   u64 inode, struct bkey_i *insert, int flags)
 223 {
 224         struct btree_iter *iter, *slot = NULL;
 225         struct bkey_s_c k;
 226         bool found = false;
 227         int ret = 0;
 228
 229         iter = bch2_trans_get_iter(trans, desc.btree_id,
 230                         POS(inode, desc.hash_bkey(info, bkey_i_to_s_c(insert))),
 231                         BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 232         if (IS_ERR(iter))
 233                 return PTR_ERR(iter);
 234
 235         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 236                 if (iter->pos.inode != inode)
 237                         break;
 238
 239                 if (k.k->type == desc.key_type) {
 240                         if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert)))
 241                                 goto found;
 242
 243                         /* hash collision: */
 244                         continue;
 245                 }
 246
 247                 if (!slot &&
 248                     !(flags & BCH_HASH_SET_MUST_REPLACE)) {
 249                         slot = bch2_trans_copy_iter(trans, iter);
 250                         if (IS_ERR(slot))
 251                                 return PTR_ERR(slot);
 252                 }
 253
 254                 if (k.k->type != KEY_TYPE_whiteout)
 255                         goto not_found;
 256         }
 257
 258         if (slot)
 259                 bch2_trans_iter_free(trans, iter);
 260
 261         return bch2_trans_iter_free(trans, iter) ?: -ENOSPC;
 262 found:
 263         found = true;
 264 not_found:
 265
 266         if (!found && (flags & BCH_HASH_SET_MUST_REPLACE)) {
 267                 ret = -ENOENT;
 268         } else if (found && (flags & BCH_HASH_SET_MUST_CREATE)) {
 269                 ret = -EEXIST;
 270         } else {
 271                 if (!found && slot) {
 272                         bch2_trans_iter_free(trans, iter);
 273                         iter = slot;
 274                 }
 275
 276                 insert->k.p = iter->pos;
 277                 bch2_trans_update(trans, BTREE_INSERT_ENTRY(iter, insert));
 278                 bch2_trans_iter_free_on_commit(trans, iter);
 279         }
 280
 281         return ret;
 282 }
 283
 284 static __always_inline
 285 int bch2_hash_delete_at(struct btree_trans *trans,
 286                         const struct bch_hash_desc desc,
 287                         const struct bch_hash_info *info,
 288                         struct btree_iter *iter)
 289 {
 290         struct bkey_i *delete;
 291         int ret;
 292
 293         ret = bch2_hash_needs_whiteout(trans, desc, info, iter);
 294         if (ret < 0)
 295                 return ret;
 296
 297         delete = bch2_trans_kmalloc(trans, sizeof(*delete));
 298         if (IS_ERR(delete))
 299                 return PTR_ERR(delete);
 300
 301         bkey_init(&delete->k);
 302         delete->k.p = iter->pos;
 303         delete->k.type = ret ? KEY_TYPE_whiteout : KEY_TYPE_deleted;
 304
 305         bch2_trans_update(trans, BTREE_INSERT_ENTRY(iter, delete));
 306         return 0;
 307 }
 308
 309 static __always_inline
 310 int bch2_hash_delete(struct btree_trans *trans,
 311                      const struct bch_hash_desc desc,
 312                      const struct bch_hash_info *info,
 313                      u64 inode, const void *key)
 314 {
 315         struct btree_iter *iter;
 316
 317         iter = bch2_hash_lookup(trans, desc, info, inode, key,
 318                                 BTREE_ITER_INTENT);
 319         if (IS_ERR(iter))
 320                 return PTR_ERR(iter);
 321
 322         return bch2_hash_delete_at(trans, desc, info, iter);
 323 }
 324
 325 #endif /* _BCACHEFS_STR_HASH_H */