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
bch2_str_hash_opt_to_type(struct bch_fs * c,enum bch_str_hash_opts opt)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
bch2_hash_info_init(struct bch_fs * c,const struct bch_inode_unpacked * bi)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
bch2_str_hash_init(struct bch_str_hash_ctx * ctx,const struct bch_hash_info * info)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
bch2_str_hash_update(struct bch_str_hash_ctx * ctx,const struct bch_hash_info * info,const void * data,size_t len)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
bch2_str_hash_end(struct bch_str_hash_ctx * ctx,const struct bch_hash_info * info)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
is_visible_key(struct bch_hash_desc desc,subvol_inum inum,struct bkey_s_c k)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
bch2_hash_lookup_in_snapshot(struct btree_trans * trans,struct btree_iter * iter,const struct bch_hash_desc desc,const struct bch_hash_info * info,subvol_inum inum,const void * key,enum btree_iter_update_trigger_flags flags,u32 snapshot)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
bch2_hash_lookup(struct btree_trans * trans,struct btree_iter * iter,const struct bch_hash_desc desc,const struct bch_hash_info * info,subvol_inum inum,const void * key,enum btree_iter_update_trigger_flags flags)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
bch2_hash_hole(struct btree_trans * trans,struct btree_iter * iter,const struct bch_hash_desc desc,const struct bch_hash_info * info,subvol_inum inum,const void * key)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
bch2_hash_needs_whiteout(struct btree_trans * trans,const struct bch_hash_desc desc,const struct bch_hash_info * info,struct btree_iter * start)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
bch2_hash_set_in_snapshot(struct btree_trans * trans,const struct bch_hash_desc desc,const struct bch_hash_info * info,subvol_inum inum,u32 snapshot,struct bkey_i * insert,enum btree_iter_update_trigger_flags flags)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
bch2_hash_set(struct btree_trans * trans,const struct bch_hash_desc desc,const struct bch_hash_info * info,subvol_inum inum,struct bkey_i * insert,enum btree_iter_update_trigger_flags flags)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
bch2_hash_delete_at(struct btree_trans * trans,const struct bch_hash_desc desc,const struct bch_hash_info * info,struct btree_iter * iter,enum btree_iter_update_trigger_flags flags)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
bch2_hash_delete(struct btree_trans * trans,const struct bch_hash_desc desc,const struct bch_hash_info * info,subvol_inum inum,const void * key)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