1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _BCACHEFS_STR_HASH_H 3 #define _BCACHEFS_STR_HASH_H 4 5 #include "btree_iter.h" 6 #include "btree_update.h" 7 #include "checksum.h" 8 #include "error.h" 9 #include "inode.h" 10 #include "siphash.h" 11 #include "subvolume.h" 12 #include "super.h" 13 14 #include <linux/crc32c.h> 15 #include <crypto/sha2.h> 16 17 static inline enum bch_str_hash_type 18 bch2_str_hash_opt_to_type(struct bch_fs *c, enum bch_str_hash_opts opt) 19 { 20 switch (opt) { 21 case BCH_STR_HASH_OPT_crc32c: 22 return BCH_STR_HASH_crc32c; 23 case BCH_STR_HASH_OPT_crc64: 24 return BCH_STR_HASH_crc64; 25 case BCH_STR_HASH_OPT_siphash: 26 return c->sb.features & (1ULL << BCH_FEATURE_new_siphash) 27 ? BCH_STR_HASH_siphash 28 : BCH_STR_HASH_siphash_old; 29 default: 30 BUG(); 31 } 32 } 33 34 struct bch_hash_info { 35 u8 type; 36 struct unicode_map *cf_encoding; 37 /* 38 * For crc32 or crc64 string hashes the first key value of 39 * the siphash_key (k0) is used as the key. 40 */ 41 SIPHASH_KEY siphash_key; 42 }; 43 44 static inline struct bch_hash_info 45 bch2_hash_info_init(struct bch_fs *c, const struct bch_inode_unpacked *bi) 46 { 47 struct bch_hash_info info = { 48 .type = INODE_STR_HASH(bi), 49 #ifdef CONFIG_UNICODE 50 .cf_encoding = bch2_inode_casefold(c, bi) ? c->cf_encoding : NULL, 51 #endif 52 .siphash_key = { .k0 = bi->bi_hash_seed } 53 }; 54 55 if (unlikely(info.type == BCH_STR_HASH_siphash_old)) { 56 u8 digest[SHA256_DIGEST_SIZE]; 57 58 sha256((const u8 *)&bi->bi_hash_seed, 59 sizeof(bi->bi_hash_seed), digest); 60 memcpy(&info.siphash_key, digest, sizeof(info.siphash_key)); 61 } 62 63 return info; 64 } 65 66 struct bch_str_hash_ctx { 67 union { 68 u32 crc32c; 69 u64 crc64; 70 SIPHASH_CTX siphash; 71 }; 72 }; 73 74 static inline void bch2_str_hash_init(struct bch_str_hash_ctx *ctx, 75 const struct bch_hash_info *info) 76 { 77 switch (info->type) { 78 case BCH_STR_HASH_crc32c: 79 ctx->crc32c = crc32c(~0, &info->siphash_key.k0, 80 sizeof(info->siphash_key.k0)); 81 break; 82 case BCH_STR_HASH_crc64: 83 ctx->crc64 = crc64_be(~0, &info->siphash_key.k0, 84 sizeof(info->siphash_key.k0)); 85 break; 86 case BCH_STR_HASH_siphash_old: 87 case BCH_STR_HASH_siphash: 88 SipHash24_Init(&ctx->siphash, &info->siphash_key); 89 break; 90 default: 91 BUG(); 92 } 93 } 94 95 static inline void bch2_str_hash_update(struct bch_str_hash_ctx *ctx, 96 const struct bch_hash_info *info, 97 const void *data, size_t len) 98 { 99 switch (info->type) { 100 case BCH_STR_HASH_crc32c: 101 ctx->crc32c = crc32c(ctx->crc32c, data, len); 102 break; 103 case BCH_STR_HASH_crc64: 104 ctx->crc64 = crc64_be(ctx->crc64, data, len); 105 break; 106 case BCH_STR_HASH_siphash_old: 107 case BCH_STR_HASH_siphash: 108 SipHash24_Update(&ctx->siphash, data, len); 109 break; 110 default: 111 BUG(); 112 } 113 } 114 115 static inline u64 bch2_str_hash_end(struct bch_str_hash_ctx *ctx, 116 const struct bch_hash_info *info) 117 { 118 switch (info->type) { 119 case BCH_STR_HASH_crc32c: 120 return ctx->crc32c; 121 case BCH_STR_HASH_crc64: 122 return ctx->crc64 >> 1; 123 case BCH_STR_HASH_siphash_old: 124 case BCH_STR_HASH_siphash: 125 return SipHash24_End(&ctx->siphash) >> 1; 126 default: 127 BUG(); 128 } 129 } 130 131 struct bch_hash_desc { 132 enum btree_id btree_id; 133 u8 key_type; 134 135 u64 (*hash_key)(const struct bch_hash_info *, const void *); 136 u64 (*hash_bkey)(const struct bch_hash_info *, struct bkey_s_c); 137 bool (*cmp_key)(struct bkey_s_c, const void *); 138 bool (*cmp_bkey)(struct bkey_s_c, struct bkey_s_c); 139 bool (*is_visible)(subvol_inum inum, struct bkey_s_c); 140 }; 141 142 static inline bool is_visible_key(struct bch_hash_desc desc, subvol_inum inum, struct bkey_s_c k) 143 { 144 return k.k->type == desc.key_type && 145 (!desc.is_visible || 146 !inum.inum || 147 desc.is_visible(inum, k)); 148 } 149 150 static __always_inline struct bkey_s_c 151 bch2_hash_lookup_in_snapshot(struct btree_trans *trans, 152 struct btree_iter *iter, 153 const struct bch_hash_desc desc, 154 const struct bch_hash_info *info, 155 subvol_inum inum, const void *key, 156 enum btree_iter_update_trigger_flags flags, 157 u32 snapshot) 158 { 159 struct bkey_s_c k; 160 int ret; 161 162 for_each_btree_key_max_norestart(trans, *iter, desc.btree_id, 163 SPOS(inum.inum, desc.hash_key(info, key), snapshot), 164 POS(inum.inum, U64_MAX), 165 BTREE_ITER_slots|flags, k, ret) { 166 if (is_visible_key(desc, inum, k)) { 167 if (!desc.cmp_key(k, key)) 168 return k; 169 } else if (k.k->type == KEY_TYPE_hash_whiteout) { 170 ; 171 } else { 172 /* hole, not found */ 173 break; 174 } 175 } 176 bch2_trans_iter_exit(trans, iter); 177 178 return bkey_s_c_err(ret ?: -BCH_ERR_ENOENT_str_hash_lookup); 179 } 180 181 static __always_inline struct bkey_s_c 182 bch2_hash_lookup(struct btree_trans *trans, 183 struct btree_iter *iter, 184 const struct bch_hash_desc desc, 185 const struct bch_hash_info *info, 186 subvol_inum inum, const void *key, 187 enum btree_iter_update_trigger_flags flags) 188 { 189 u32 snapshot; 190 int ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); 191 if (ret) 192 return bkey_s_c_err(ret); 193 194 return bch2_hash_lookup_in_snapshot(trans, iter, desc, info, inum, key, flags, snapshot); 195 } 196 197 static __always_inline int 198 bch2_hash_hole(struct btree_trans *trans, 199 struct btree_iter *iter, 200 const struct bch_hash_desc desc, 201 const struct bch_hash_info *info, 202 subvol_inum inum, const void *key) 203 { 204 struct bkey_s_c k; 205 u32 snapshot; 206 int ret; 207 208 ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); 209 if (ret) 210 return ret; 211 212 for_each_btree_key_max_norestart(trans, *iter, desc.btree_id, 213 SPOS(inum.inum, desc.hash_key(info, key), snapshot), 214 POS(inum.inum, U64_MAX), 215 BTREE_ITER_slots|BTREE_ITER_intent, k, ret) 216 if (!is_visible_key(desc, inum, k)) 217 return 0; 218 bch2_trans_iter_exit(trans, iter); 219 220 return ret ?: -BCH_ERR_ENOSPC_str_hash_create; 221 } 222 223 static __always_inline 224 int bch2_hash_needs_whiteout(struct btree_trans *trans, 225 const struct bch_hash_desc desc, 226 const struct bch_hash_info *info, 227 struct btree_iter *start) 228 { 229 struct btree_iter iter; 230 struct bkey_s_c k; 231 int ret; 232 233 bch2_trans_copy_iter(trans, &iter, start); 234 235 bch2_btree_iter_advance(trans, &iter); 236 237 for_each_btree_key_continue_norestart(trans, iter, BTREE_ITER_slots, k, ret) { 238 if (k.k->type != desc.key_type && 239 k.k->type != KEY_TYPE_hash_whiteout) 240 break; 241 242 if (k.k->type == desc.key_type && 243 desc.hash_bkey(info, k) <= start->pos.offset) { 244 ret = 1; 245 break; 246 } 247 } 248 249 bch2_trans_iter_exit(trans, &iter); 250 return ret; 251 } 252 253 static __always_inline 254 struct bkey_s_c bch2_hash_set_or_get_in_snapshot(struct btree_trans *trans, 255 struct btree_iter *iter, 256 const struct bch_hash_desc desc, 257 const struct bch_hash_info *info, 258 subvol_inum inum, u32 snapshot, 259 struct bkey_i *insert, 260 enum btree_iter_update_trigger_flags flags) 261 { 262 struct btree_iter slot = {}; 263 struct bkey_s_c k; 264 bool found = false; 265 int ret; 266 267 for_each_btree_key_max_norestart(trans, *iter, desc.btree_id, 268 SPOS(insert->k.p.inode, 269 desc.hash_bkey(info, bkey_i_to_s_c(insert)), 270 snapshot), 271 POS(insert->k.p.inode, U64_MAX), 272 BTREE_ITER_slots|BTREE_ITER_intent|flags, k, ret) { 273 if (is_visible_key(desc, inum, k)) { 274 if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert))) 275 goto found; 276 277 /* hash collision: */ 278 continue; 279 } 280 281 if (!slot.path && !(flags & STR_HASH_must_replace)) 282 bch2_trans_copy_iter(trans, &slot, iter); 283 284 if (k.k->type != KEY_TYPE_hash_whiteout) 285 goto not_found; 286 } 287 288 if (!ret) 289 ret = -BCH_ERR_ENOSPC_str_hash_create; 290 out: 291 bch2_trans_iter_exit(trans, &slot); 292 bch2_trans_iter_exit(trans, iter); 293 return ret ? bkey_s_c_err(ret) : bkey_s_c_null; 294 found: 295 found = true; 296 not_found: 297 if (found && (flags & STR_HASH_must_create)) { 298 bch2_trans_iter_exit(trans, &slot); 299 return k; 300 } else if (!found && (flags & STR_HASH_must_replace)) { 301 ret = -BCH_ERR_ENOENT_str_hash_set_must_replace; 302 } else { 303 if (!found && slot.path) 304 swap(*iter, slot); 305 306 insert->k.p = iter->pos; 307 ret = bch2_trans_update(trans, iter, insert, flags); 308 } 309 310 goto out; 311 } 312 313 static __always_inline 314 int bch2_hash_set_in_snapshot(struct btree_trans *trans, 315 const struct bch_hash_desc desc, 316 const struct bch_hash_info *info, 317 subvol_inum inum, u32 snapshot, 318 struct bkey_i *insert, 319 enum btree_iter_update_trigger_flags flags) 320 { 321 struct btree_iter iter; 322 struct bkey_s_c k = bch2_hash_set_or_get_in_snapshot(trans, &iter, desc, info, inum, 323 snapshot, insert, flags); 324 int ret = bkey_err(k); 325 if (ret) 326 return ret; 327 if (k.k) { 328 bch2_trans_iter_exit(trans, &iter); 329 return -BCH_ERR_EEXIST_str_hash_set; 330 } 331 332 return 0; 333 } 334 335 static __always_inline 336 int bch2_hash_set(struct btree_trans *trans, 337 const struct bch_hash_desc desc, 338 const struct bch_hash_info *info, 339 subvol_inum inum, 340 struct bkey_i *insert, 341 enum btree_iter_update_trigger_flags flags) 342 { 343 insert->k.p.inode = inum.inum; 344 345 u32 snapshot; 346 return bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot) ?: 347 bch2_hash_set_in_snapshot(trans, desc, info, inum, 348 snapshot, insert, flags); 349 } 350 351 static __always_inline 352 int bch2_hash_delete_at(struct btree_trans *trans, 353 const struct bch_hash_desc desc, 354 const struct bch_hash_info *info, 355 struct btree_iter *iter, 356 enum btree_iter_update_trigger_flags flags) 357 { 358 struct bkey_i *delete; 359 int ret; 360 361 delete = bch2_trans_kmalloc(trans, sizeof(*delete)); 362 ret = PTR_ERR_OR_ZERO(delete); 363 if (ret) 364 return ret; 365 366 ret = bch2_hash_needs_whiteout(trans, desc, info, iter); 367 if (ret < 0) 368 return ret; 369 370 bkey_init(&delete->k); 371 delete->k.p = iter->pos; 372 delete->k.type = ret ? KEY_TYPE_hash_whiteout : KEY_TYPE_deleted; 373 374 return bch2_trans_update(trans, iter, delete, flags); 375 } 376 377 static __always_inline 378 int bch2_hash_delete(struct btree_trans *trans, 379 const struct bch_hash_desc desc, 380 const struct bch_hash_info *info, 381 subvol_inum inum, const void *key) 382 { 383 struct btree_iter iter; 384 struct bkey_s_c k = bch2_hash_lookup(trans, &iter, desc, info, inum, key, 385 BTREE_ITER_intent); 386 int ret = bkey_err(k); 387 if (ret) 388 return ret; 389 390 ret = bch2_hash_delete_at(trans, desc, info, &iter, 0); 391 bch2_trans_iter_exit(trans, &iter); 392 return ret; 393 } 394 395 struct snapshots_seen; 396 int __bch2_str_hash_check_key(struct btree_trans *, 397 struct snapshots_seen *, 398 const struct bch_hash_desc *, 399 struct bch_hash_info *, 400 struct btree_iter *, struct bkey_s_c); 401 402 static inline int bch2_str_hash_check_key(struct btree_trans *trans, 403 struct snapshots_seen *s, 404 const struct bch_hash_desc *desc, 405 struct bch_hash_info *hash_info, 406 struct btree_iter *k_iter, struct bkey_s_c hash_k) 407 { 408 if (hash_k.k->type != desc->key_type) 409 return 0; 410 411 if (likely(desc->hash_bkey(hash_info, hash_k) == hash_k.k->p.offset)) 412 return 0; 413 414 return __bch2_str_hash_check_key(trans, s, desc, hash_info, k_iter, hash_k); 415 } 416 417 #endif /* _BCACHEFS_STR_HASH_H */ 418