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Update bcachefs sources to 6f603b8d79 bcachefs: some improvements to startup messages...
[bcachefs-tools-debian] / libbcachefs / dirent.c
1
2 #include "bcachefs.h"
3 #include "bkey_methods.h"
4 #include "btree_update.h"
5 #include "extents.h"
6 #include "dirent.h"
7 #include "fs.h"
8 #include "keylist.h"
9 #include "str_hash.h"
10
11 #include <linux/dcache.h>
12
13 unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
14 {
15         unsigned len = bkey_val_bytes(d.k) -
16                 offsetof(struct bch_dirent, d_name);
17
18         return strnlen(d.v->d_name, len);
19 }
20
21 static u64 bch2_dirent_hash(const struct bch_hash_info *info,
22                             const struct qstr *name)
23 {
24         struct bch_str_hash_ctx ctx;
25
26         bch2_str_hash_init(&ctx, info);
27         bch2_str_hash_update(&ctx, info, name->name, name->len);
28
29         /* [0,2) reserved for dots */
30         return max_t(u64, bch2_str_hash_end(&ctx, info), 2);
31 }
32
33 static u64 dirent_hash_key(const struct bch_hash_info *info, const void *key)
34 {
35         return bch2_dirent_hash(info, key);
36 }
37
38 static u64 dirent_hash_bkey(const struct bch_hash_info *info, struct bkey_s_c k)
39 {
40         struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
41         struct qstr name = QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(d));
42
43         return bch2_dirent_hash(info, &name);
44 }
45
46 static bool dirent_cmp_key(struct bkey_s_c _l, const void *_r)
47 {
48         struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
49         int len = bch2_dirent_name_bytes(l);
50         const struct qstr *r = _r;
51
52         return len - r->len ?: memcmp(l.v->d_name, r->name, len);
53 }
54
55 static bool dirent_cmp_bkey(struct bkey_s_c _l, struct bkey_s_c _r)
56 {
57         struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
58         struct bkey_s_c_dirent r = bkey_s_c_to_dirent(_r);
59         int l_len = bch2_dirent_name_bytes(l);
60         int r_len = bch2_dirent_name_bytes(r);
61
62         return l_len - r_len ?: memcmp(l.v->d_name, r.v->d_name, l_len);
63 }
64
65 const struct bch_hash_desc bch2_dirent_hash_desc = {
66         .btree_id       = BTREE_ID_DIRENTS,
67         .key_type       = KEY_TYPE_dirent,
68         .hash_key       = dirent_hash_key,
69         .hash_bkey      = dirent_hash_bkey,
70         .cmp_key        = dirent_cmp_key,
71         .cmp_bkey       = dirent_cmp_bkey,
72 };
73
74 const char *bch2_dirent_invalid(const struct bch_fs *c, struct bkey_s_c k)
75 {
76         struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
77         unsigned len;
78
79         if (bkey_val_bytes(k.k) < sizeof(struct bch_dirent))
80                 return "value too small";
81
82         len = bch2_dirent_name_bytes(d);
83         if (!len)
84                 return "empty name";
85
86         /*
87          * older versions of bcachefs were buggy and creating dirent
88          * keys that were bigger than necessary:
89          */
90         if (bkey_val_u64s(k.k) > dirent_val_u64s(len + 7))
91                 return "value too big";
92
93         if (len > BCH_NAME_MAX)
94                 return "dirent name too big";
95
96         return NULL;
97 }
98
99 void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c,
100                          struct bkey_s_c k)
101 {
102         struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
103
104         bch_scnmemcpy(out, d.v->d_name,
105                       bch2_dirent_name_bytes(d));
106         pr_buf(out, " -> %llu", d.v->d_inum);
107 }
108
109 static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
110                                 u8 type, const struct qstr *name, u64 dst)
111 {
112         struct bkey_i_dirent *dirent;
113         unsigned u64s = BKEY_U64s + dirent_val_u64s(name->len);
114
115         if (name->len > BCH_NAME_MAX)
116                 return ERR_PTR(-ENAMETOOLONG);
117
118         BUG_ON(u64s > U8_MAX);
119
120         dirent = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
121         if (IS_ERR(dirent))
122                 return dirent;
123
124         bkey_dirent_init(&dirent->k_i);
125         dirent->k.u64s = u64s;
126         dirent->v.d_inum = cpu_to_le64(dst);
127         dirent->v.d_type = type;
128
129         memcpy(dirent->v.d_name, name->name, name->len);
130         memset(dirent->v.d_name + name->len, 0,
131                bkey_val_bytes(&dirent->k) -
132                offsetof(struct bch_dirent, d_name) -
133                name->len);
134
135         EBUG_ON(bch2_dirent_name_bytes(dirent_i_to_s_c(dirent)) != name->len);
136
137         return dirent;
138 }
139
140 int __bch2_dirent_create(struct btree_trans *trans,
141                          u64 dir_inum, const struct bch_hash_info *hash_info,
142                          u8 type, const struct qstr *name, u64 dst_inum,
143                          int flags)
144 {
145         struct bkey_i_dirent *dirent;
146         int ret;
147
148         dirent = dirent_create_key(trans, type, name, dst_inum);
149         ret = PTR_ERR_OR_ZERO(dirent);
150         if (ret)
151                 return ret;
152
153         return bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
154                              dir_inum, &dirent->k_i, flags);
155 }
156
157 int bch2_dirent_create(struct bch_fs *c, u64 dir_inum,
158                        const struct bch_hash_info *hash_info,
159                        u8 type, const struct qstr *name, u64 dst_inum,
160                        u64 *journal_seq, int flags)
161 {
162         return bch2_trans_do(c, journal_seq, flags,
163                 __bch2_dirent_create(&trans, dir_inum, hash_info,
164                                      type, name, dst_inum, flags));
165 }
166
167 static void dirent_copy_target(struct bkey_i_dirent *dst,
168                                struct bkey_s_c_dirent src)
169 {
170         dst->v.d_inum = src.v->d_inum;
171         dst->v.d_type = src.v->d_type;
172 }
173
174 static struct bpos bch2_dirent_pos(struct bch_inode_info *inode,
175                                    const struct qstr *name)
176 {
177         return POS(inode->v.i_ino, bch2_dirent_hash(&inode->ei_str_hash, name));
178 }
179
180 int bch2_dirent_rename(struct btree_trans *trans,
181                 struct bch_inode_info *src_dir, const struct qstr *src_name,
182                 struct bch_inode_info *dst_dir, const struct qstr *dst_name,
183                 enum bch_rename_mode mode)
184 {
185         struct btree_iter *src_iter, *dst_iter;
186         struct bkey_s_c old_src, old_dst;
187         struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
188         struct bpos dst_pos = bch2_dirent_pos(dst_dir, dst_name);
189         int ret;
190
191         /*
192          * Lookup dst:
193          *
194          * Note that in BCH_RENAME mode, we're _not_ checking if
195          * the target already exists - we're relying on the VFS
196          * to do that check for us for correctness:
197          */
198         dst_iter = mode == BCH_RENAME
199                 ? bch2_hash_hole(trans, bch2_dirent_hash_desc,
200                                  &dst_dir->ei_str_hash,
201                                  dst_dir->v.i_ino, dst_name)
202                 : bch2_hash_lookup(trans, bch2_dirent_hash_desc,
203                                    &dst_dir->ei_str_hash,
204                                    dst_dir->v.i_ino, dst_name,
205                                    BTREE_ITER_INTENT);
206         if (IS_ERR(dst_iter))
207                 return PTR_ERR(dst_iter);
208         old_dst = bch2_btree_iter_peek_slot(dst_iter);
209
210         /* Lookup src: */
211         src_iter = bch2_hash_lookup(trans, bch2_dirent_hash_desc,
212                                     &src_dir->ei_str_hash,
213                                     src_dir->v.i_ino, src_name,
214                                     BTREE_ITER_INTENT);
215         if (IS_ERR(src_iter))
216                 return PTR_ERR(src_iter);
217         old_src = bch2_btree_iter_peek_slot(src_iter);
218
219         /* Create new dst key: */
220         new_dst = dirent_create_key(trans, 0, dst_name, 0);
221         if (IS_ERR(new_dst))
222                 return PTR_ERR(new_dst);
223
224         dirent_copy_target(new_dst, bkey_s_c_to_dirent(old_src));
225         new_dst->k.p = dst_iter->pos;
226
227         /* Create new src key: */
228         if (mode == BCH_RENAME_EXCHANGE) {
229                 new_src = dirent_create_key(trans, 0, src_name, 0);
230                 if (IS_ERR(new_src))
231                         return PTR_ERR(new_src);
232
233                 dirent_copy_target(new_src, bkey_s_c_to_dirent(old_dst));
234                 new_src->k.p = src_iter->pos;
235         } else {
236                 new_src = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
237                 if (IS_ERR(new_src))
238                         return PTR_ERR(new_src);
239                 bkey_init(&new_src->k);
240                 new_src->k.p = src_iter->pos;
241
242                 if (bkey_cmp(dst_pos, src_iter->pos) <= 0 &&
243                     bkey_cmp(src_iter->pos, dst_iter->pos) < 0) {
244                         /*
245                          * We have a hash collision for the new dst key,
246                          * and new_src - the key we're deleting - is between
247                          * new_dst's hashed slot and the slot we're going to be
248                          * inserting it into - oops.  This will break the hash
249                          * table if we don't deal with it:
250                          */
251                         if (mode == BCH_RENAME) {
252                                 /*
253                                  * If we're not overwriting, we can just insert
254                                  * new_dst at the src position:
255                                  */
256                                 new_dst->k.p = src_iter->pos;
257                                 bch2_trans_update(trans,
258                                         BTREE_INSERT_ENTRY(src_iter,
259                                                            &new_dst->k_i));
260                                 return 0;
261                         } else {
262                                 /* If we're overwriting, we can't insert new_dst
263                                  * at a different slot because it has to
264                                  * overwrite old_dst - just make sure to use a
265                                  * whiteout when deleting src:
266                                  */
267                                 new_src->k.type = KEY_TYPE_whiteout;
268                         }
269                 } else {
270                         /* Check if we need a whiteout to delete src: */
271                         ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc,
272                                                        &src_dir->ei_str_hash,
273                                                        src_iter);
274                         if (ret < 0)
275                                 return ret;
276
277                         if (ret)
278                                 new_src->k.type = KEY_TYPE_whiteout;
279                 }
280         }
281
282         bch2_trans_update(trans, BTREE_INSERT_ENTRY(src_iter, &new_src->k_i));
283         bch2_trans_update(trans, BTREE_INSERT_ENTRY(dst_iter, &new_dst->k_i));
284         return 0;
285 }
286
287 int __bch2_dirent_delete(struct btree_trans *trans, u64 dir_inum,
288                          const struct bch_hash_info *hash_info,
289                          const struct qstr *name)
290 {
291         return bch2_hash_delete(trans, bch2_dirent_hash_desc, hash_info,
292                                 dir_inum, name);
293 }
294
295 int bch2_dirent_delete(struct bch_fs *c, u64 dir_inum,
296                        const struct bch_hash_info *hash_info,
297                        const struct qstr *name,
298                        u64 *journal_seq)
299 {
300         return bch2_trans_do(c, journal_seq,
301                              BTREE_INSERT_ATOMIC|
302                              BTREE_INSERT_NOFAIL,
303                 __bch2_dirent_delete(&trans, dir_inum, hash_info, name));
304 }
305
306 u64 bch2_dirent_lookup(struct bch_fs *c, u64 dir_inum,
307                        const struct bch_hash_info *hash_info,
308                        const struct qstr *name)
309 {
310         struct btree_trans trans;
311         struct btree_iter *iter;
312         struct bkey_s_c k;
313         u64 inum = 0;
314
315         bch2_trans_init(&trans, c);
316
317         iter = bch2_hash_lookup(&trans, bch2_dirent_hash_desc,
318                                 hash_info, dir_inum, name, 0);
319         if (IS_ERR(iter)) {
320                 BUG_ON(PTR_ERR(iter) == -EINTR);
321                 goto out;
322         }
323
324         k = bch2_btree_iter_peek_slot(iter);
325         inum = le64_to_cpu(bkey_s_c_to_dirent(k).v->d_inum);
326 out:
327         bch2_trans_exit(&trans);
328         return inum;
329 }
330
331 int bch2_empty_dir_trans(struct btree_trans *trans, u64 dir_inum)
332 {
333         struct btree_iter *iter;
334         struct bkey_s_c k;
335         int ret;
336
337         for_each_btree_key(trans, iter, BTREE_ID_DIRENTS,
338                            POS(dir_inum, 0), 0, k, ret) {
339                 if (k.k->p.inode > dir_inum)
340                         break;
341
342                 if (k.k->type == KEY_TYPE_dirent) {
343                         ret = -ENOTEMPTY;
344                         break;
345                 }
346         }
347         bch2_trans_iter_put(trans, iter);
348
349         return ret;
350 }
351
352 int bch2_empty_dir(struct bch_fs *c, u64 dir_inum)
353 {
354         return bch2_trans_do(c, NULL, 0,
355                 bch2_empty_dir_trans(&trans, dir_inum));
356 }
357
358 int bch2_readdir(struct bch_fs *c, struct file *file,
359                  struct dir_context *ctx)
360 {
361         struct bch_inode_info *inode = file_bch_inode(file);
362         struct btree_trans trans;
363         struct btree_iter *iter;
364         struct bkey_s_c k;
365         struct bkey_s_c_dirent dirent;
366         unsigned len;
367         int ret;
368
369         if (!dir_emit_dots(file, ctx))
370                 return 0;
371
372         bch2_trans_init(&trans, c);
373
374         for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS,
375                            POS(inode->v.i_ino, ctx->pos), 0, k, ret) {
376                 if (k.k->type != KEY_TYPE_dirent)
377                         continue;
378
379                 dirent = bkey_s_c_to_dirent(k);
380
381                 if (bkey_cmp(k.k->p, POS(inode->v.i_ino, ctx->pos)) < 0)
382                         continue;
383
384                 if (k.k->p.inode > inode->v.i_ino)
385                         break;
386
387                 len = bch2_dirent_name_bytes(dirent);
388
389                 /*
390                  * XXX: dir_emit() can fault and block, while we're holding
391                  * locks
392                  */
393                 if (!dir_emit(ctx, dirent.v->d_name, len,
394                               le64_to_cpu(dirent.v->d_inum),
395                               dirent.v->d_type))
396                         break;
397
398                 ctx->pos = k.k->p.offset + 1;
399         }
400         ret = bch2_trans_exit(&trans) ?: ret;
401
402         return ret;
403 }