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