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         u8              whiteout_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 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 == desc.whiteout_type) {
 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 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 inline int bch2_hash_needs_whiteout(struct btree_trans *trans,
 189                                            const struct bch_hash_desc desc,
 190                                            const struct bch_hash_info *info,
 191                                            struct btree_iter *start)
 192 {
 193         struct btree_iter *iter;
 194         struct bkey_s_c k;
 195
 196         iter = bch2_trans_copy_iter(trans, start);
 197         if (IS_ERR(iter))
 198                 return PTR_ERR(iter);
 199
 200         bch2_btree_iter_next_slot(iter);
 201
 202         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 203                 if (k.k->type != desc.key_type &&
 204                     k.k->type != desc.whiteout_type)
 205                         return false;
 206
 207                 if (k.k->type == desc.key_type &&
 208                     desc.hash_bkey(info, k) <= start->pos.offset)
 209                         return true;
 210         }
 211         return btree_iter_err(k);
 212 }
 213
 214 static inline int __bch2_hash_set(struct btree_trans *trans,
 215                                   const struct bch_hash_desc desc,
 216                                   const struct bch_hash_info *info,
 217                                   u64 inode, struct bkey_i *insert, int flags)
 218 {
 219         struct btree_iter *iter, *slot = NULL;
 220         struct bkey_s_c k;
 221
 222         iter = bch2_trans_get_iter(trans, desc.btree_id,
 223                         POS(inode, desc.hash_bkey(info, bkey_i_to_s_c(insert))),
 224                         BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 225         if (IS_ERR(iter))
 226                 return PTR_ERR(iter);
 227
 228         for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
 229                 if (iter->pos.inode != inode)
 230                         break;
 231
 232                 if (k.k->type == desc.key_type) {
 233                         if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert)))
 234                                 goto found;
 235
 236                         /* hash collision: */
 237                         continue;
 238                 }
 239
 240                 if (!slot &&
 241                     !(flags & BCH_HASH_SET_MUST_REPLACE)) {
 242                         slot = bch2_trans_copy_iter(trans, iter);
 243                         if (IS_ERR(slot))
 244                                 return PTR_ERR(slot);
 245                 }
 246
 247                 if (k.k->type != desc.whiteout_type)
 248                         goto not_found;
 249         }
 250
 251         return btree_iter_err(k) ?: -ENOSPC;
 252 not_found:
 253         if (flags & BCH_HASH_SET_MUST_REPLACE)
 254                 return -ENOENT;
 255
 256         insert->k.p = slot->pos;
 257         bch2_trans_update(trans, BTREE_INSERT_ENTRY(slot, insert));
 258         return 0;
 259 found:
 260         if (flags & BCH_HASH_SET_MUST_CREATE)
 261                 return -EEXIST;
 262
 263         insert->k.p = iter->pos;
 264         bch2_trans_update(trans, BTREE_INSERT_ENTRY(iter, insert));
 265         return 0;
 266 }
 267
 268 static inline int bch2_hash_set(const struct bch_hash_desc desc,
 269                                const struct bch_hash_info *info,
 270                                struct bch_fs *c, u64 inode,
 271                                u64 *journal_seq,
 272                                struct bkey_i *insert, int flags)
 273 {
 274         return bch2_trans_do(c, journal_seq, flags|BTREE_INSERT_ATOMIC,
 275                         __bch2_hash_set(&trans, desc, info,
 276                                         inode, insert, flags));
 277 }
 278
 279 static inline int bch2_hash_delete_at(struct btree_trans *trans,
 280                                       const struct bch_hash_desc desc,
 281                                       const struct bch_hash_info *info,
 282                                       struct btree_iter *iter)
 283 {
 284         struct bkey_i *delete;
 285         int ret;
 286
 287         ret = bch2_hash_needs_whiteout(trans, desc, info, iter);
 288         if (ret < 0)
 289                 return ret;
 290
 291         delete = bch2_trans_kmalloc(trans, sizeof(*delete));
 292         if (IS_ERR(delete))
 293                 return PTR_ERR(delete);
 294
 295         bkey_init(&delete->k);
 296         delete->k.p = iter->pos;
 297         delete->k.type = ret ? desc.whiteout_type : KEY_TYPE_DELETED;
 298
 299         bch2_trans_update(trans, BTREE_INSERT_ENTRY(iter, delete));
 300         return 0;
 301 }
 302
 303 static inline int bch2_hash_delete(struct btree_trans *trans,
 304                                    const struct bch_hash_desc desc,
 305                                    const struct bch_hash_info *info,
 306                                    u64 inode, const void *key)
 307 {
 308         struct btree_iter *iter;
 309
 310         iter = bch2_hash_lookup(trans, desc, info, inode, key,
 311                                 BTREE_ITER_INTENT);
 312         if (IS_ERR(iter))
 313                 return PTR_ERR(iter);
 314
 315         return bch2_hash_delete_at(trans, desc, info, iter);
 316 }
 317
 318 #endif /* _BCACHEFS_STR_HASH_H */