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

source code of linux/fs/bcachefs/str_hash.h