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 int 153 bch2_hash_lookup(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 unsigned flags) 159 { 160 struct bkey_s_c k; 161 u32 snapshot; 162 int ret; 163 164 ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); 165 if (ret) 166 return ret; 167 168 for_each_btree_key_upto_norestart(trans, *iter, desc.btree_id, 169 SPOS(inum.inum, desc.hash_key(info, key), snapshot), 170 POS(inum.inum, U64_MAX), 171 BTREE_ITER_SLOTS|flags, k, ret) { 172 if (is_visible_key(desc, inum, k)) { 173 if (!desc.cmp_key(k, key)) 174 return 0; 175 } else if (k.k->type == KEY_TYPE_hash_whiteout) { 176 ; 177 } else { 178 /* hole, not found */ 179 break; 180 } 181 } 182 bch2_trans_iter_exit(trans, iter); 183 184 return ret ?: -BCH_ERR_ENOENT_str_hash_lookup; 185 } 186 187 static __always_inline int 188 bch2_hash_hole(struct btree_trans *trans, 189 struct btree_iter *iter, 190 const struct bch_hash_desc desc, 191 const struct bch_hash_info *info, 192 subvol_inum inum, const void *key) 193 { 194 struct bkey_s_c k; 195 u32 snapshot; 196 int ret; 197 198 ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); 199 if (ret) 200 return ret; 201 202 for_each_btree_key_upto_norestart(trans, *iter, desc.btree_id, 203 SPOS(inum.inum, desc.hash_key(info, key), snapshot), 204 POS(inum.inum, U64_MAX), 205 BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) 206 if (!is_visible_key(desc, inum, k)) 207 return 0; 208 bch2_trans_iter_exit(trans, iter); 209 210 return ret ?: -BCH_ERR_ENOSPC_str_hash_create; 211 } 212 213 static __always_inline 214 int bch2_hash_needs_whiteout(struct btree_trans *trans, 215 const struct bch_hash_desc desc, 216 const struct bch_hash_info *info, 217 struct btree_iter *start) 218 { 219 struct btree_iter iter; 220 struct bkey_s_c k; 221 int ret; 222 223 bch2_trans_copy_iter(&iter, start); 224 225 bch2_btree_iter_advance(&iter); 226 227 for_each_btree_key_continue_norestart(iter, BTREE_ITER_SLOTS, k, ret) { 228 if (k.k->type != desc.key_type && 229 k.k->type != KEY_TYPE_hash_whiteout) 230 break; 231 232 if (k.k->type == desc.key_type && 233 desc.hash_bkey(info, k) <= start->pos.offset) { 234 ret = 1; 235 break; 236 } 237 } 238 239 bch2_trans_iter_exit(trans, &iter); 240 return ret; 241 } 242 243 static __always_inline 244 int bch2_hash_set_snapshot(struct btree_trans *trans, 245 const struct bch_hash_desc desc, 246 const struct bch_hash_info *info, 247 subvol_inum inum, u32 snapshot, 248 struct bkey_i *insert, 249 int flags, 250 int update_flags) 251 { 252 struct btree_iter iter, slot = { NULL }; 253 struct bkey_s_c k; 254 bool found = false; 255 int ret; 256 257 for_each_btree_key_upto_norestart(trans, iter, desc.btree_id, 258 SPOS(insert->k.p.inode, 259 desc.hash_bkey(info, bkey_i_to_s_c(insert)), 260 snapshot), 261 POS(insert->k.p.inode, U64_MAX), 262 BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) { 263 if (is_visible_key(desc, inum, k)) { 264 if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert))) 265 goto found; 266 267 /* hash collision: */ 268 continue; 269 } 270 271 if (!slot.path && 272 !(flags & BCH_HASH_SET_MUST_REPLACE)) 273 bch2_trans_copy_iter(&slot, &iter); 274 275 if (k.k->type != KEY_TYPE_hash_whiteout) 276 goto not_found; 277 } 278 279 if (!ret) 280 ret = -BCH_ERR_ENOSPC_str_hash_create; 281 out: 282 bch2_trans_iter_exit(trans, &slot); 283 bch2_trans_iter_exit(trans, &iter); 284 285 return ret; 286 found: 287 found = true; 288 not_found: 289 290 if (!found && (flags & BCH_HASH_SET_MUST_REPLACE)) { 291 ret = -BCH_ERR_ENOENT_str_hash_set_must_replace; 292 } else if (found && (flags & BCH_HASH_SET_MUST_CREATE)) { 293 ret = -EEXIST; 294 } else { 295 if (!found && slot.path) 296 swap(iter, slot); 297 298 insert->k.p = iter.pos; 299 ret = bch2_trans_update(trans, &iter, insert, 0); 300 } 301 302 goto out; 303 } 304 305 static __always_inline 306 int bch2_hash_set(struct btree_trans *trans, 307 const struct bch_hash_desc desc, 308 const struct bch_hash_info *info, 309 subvol_inum inum, 310 struct bkey_i *insert, int flags) 311 { 312 u32 snapshot; 313 int ret; 314 315 ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); 316 if (ret) 317 return ret; 318 319 insert->k.p.inode = inum.inum; 320 321 return bch2_hash_set_snapshot(trans, desc, info, inum, 322 snapshot, insert, flags, 0); 323 } 324 325 static __always_inline 326 int bch2_hash_delete_at(struct btree_trans *trans, 327 const struct bch_hash_desc desc, 328 const struct bch_hash_info *info, 329 struct btree_iter *iter, 330 unsigned update_flags) 331 { 332 struct bkey_i *delete; 333 int ret; 334 335 delete = bch2_trans_kmalloc(trans, sizeof(*delete)); 336 ret = PTR_ERR_OR_ZERO(delete); 337 if (ret) 338 return ret; 339 340 ret = bch2_hash_needs_whiteout(trans, desc, info, iter); 341 if (ret < 0) 342 return ret; 343 344 bkey_init(&delete->k); 345 delete->k.p = iter->pos; 346 delete->k.type = ret ? KEY_TYPE_hash_whiteout : KEY_TYPE_deleted; 347 348 return bch2_trans_update(trans, iter, delete, update_flags); 349 } 350 351 static __always_inline 352 int bch2_hash_delete(struct btree_trans *trans, 353 const struct bch_hash_desc desc, 354 const struct bch_hash_info *info, 355 subvol_inum inum, const void *key) 356 { 357 struct btree_iter iter; 358 int ret; 359 360 ret = bch2_hash_lookup(trans, &iter, desc, info, inum, key, 361 BTREE_ITER_INTENT); 362 if (ret) 363 return ret; 364 365 ret = bch2_hash_delete_at(trans, desc, info, &iter, 0); 366 bch2_trans_iter_exit(trans, &iter); 367 return ret; 368 } 369 370 #endif /* _BCACHEFS_STR_HASH_H */ 371