xref: /linux/fs/bcachefs/namei.c (revision 4a4b30ea80d8cb5e8c4c62bb86201f4ea0d9b030)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include "bcachefs.h"
4 #include "acl.h"
5 #include "btree_update.h"
6 #include "dirent.h"
7 #include "inode.h"
8 #include "namei.h"
9 #include "subvolume.h"
10 #include "xattr.h"
11 
12 #include <linux/posix_acl.h>
13 
is_subdir_for_nlink(struct bch_inode_unpacked * inode)14 static inline int is_subdir_for_nlink(struct bch_inode_unpacked *inode)
15 {
16 	return S_ISDIR(inode->bi_mode) && !inode->bi_subvol;
17 }
18 
bch2_create_trans(struct btree_trans * trans,subvol_inum dir,struct bch_inode_unpacked * dir_u,struct bch_inode_unpacked * new_inode,const struct qstr * name,uid_t uid,gid_t gid,umode_t mode,dev_t rdev,struct posix_acl * default_acl,struct posix_acl * acl,subvol_inum snapshot_src,unsigned flags)19 int bch2_create_trans(struct btree_trans *trans,
20 		      subvol_inum dir,
21 		      struct bch_inode_unpacked *dir_u,
22 		      struct bch_inode_unpacked *new_inode,
23 		      const struct qstr *name,
24 		      uid_t uid, gid_t gid, umode_t mode, dev_t rdev,
25 		      struct posix_acl *default_acl,
26 		      struct posix_acl *acl,
27 		      subvol_inum snapshot_src,
28 		      unsigned flags)
29 {
30 	struct bch_fs *c = trans->c;
31 	struct btree_iter dir_iter = { NULL };
32 	struct btree_iter inode_iter = { NULL };
33 	subvol_inum new_inum = dir;
34 	u64 now = bch2_current_time(c);
35 	u64 cpu = raw_smp_processor_id();
36 	u64 dir_target;
37 	u32 snapshot;
38 	unsigned dir_type = mode_to_type(mode);
39 	int ret;
40 
41 	ret = bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot);
42 	if (ret)
43 		goto err;
44 
45 	ret = bch2_inode_peek(trans, &dir_iter, dir_u, dir,
46 			      BTREE_ITER_intent|BTREE_ITER_with_updates);
47 	if (ret)
48 		goto err;
49 
50 	/* Inherit casefold state from parent. */
51 	if (S_ISDIR(mode))
52 		new_inode->bi_flags |= dir_u->bi_flags & BCH_INODE_casefolded;
53 
54 	if (!(flags & BCH_CREATE_SNAPSHOT)) {
55 		/* Normal create path - allocate a new inode: */
56 		bch2_inode_init_late(new_inode, now, uid, gid, mode, rdev, dir_u);
57 
58 		if (flags & BCH_CREATE_TMPFILE)
59 			new_inode->bi_flags |= BCH_INODE_unlinked;
60 
61 		ret = bch2_inode_create(trans, &inode_iter, new_inode, snapshot, cpu);
62 		if (ret)
63 			goto err;
64 
65 		snapshot_src = (subvol_inum) { 0 };
66 	} else {
67 		/*
68 		 * Creating a snapshot - we're not allocating a new inode, but
69 		 * we do have to lookup the root inode of the subvolume we're
70 		 * snapshotting and update it (in the new snapshot):
71 		 */
72 
73 		if (!snapshot_src.inum) {
74 			/* Inode wasn't specified, just snapshot: */
75 			struct bch_subvolume s;
76 			ret = bch2_subvolume_get(trans, snapshot_src.subvol, true, &s);
77 			if (ret)
78 				goto err;
79 
80 			snapshot_src.inum = le64_to_cpu(s.inode);
81 		}
82 
83 		ret = bch2_inode_peek(trans, &inode_iter, new_inode, snapshot_src,
84 				      BTREE_ITER_intent);
85 		if (ret)
86 			goto err;
87 
88 		if (new_inode->bi_subvol != snapshot_src.subvol) {
89 			/* Not a subvolume root: */
90 			ret = -EINVAL;
91 			goto err;
92 		}
93 
94 		/*
95 		 * If we're not root, we have to own the subvolume being
96 		 * snapshotted:
97 		 */
98 		if (uid && new_inode->bi_uid != uid) {
99 			ret = -EPERM;
100 			goto err;
101 		}
102 
103 		flags |= BCH_CREATE_SUBVOL;
104 	}
105 
106 	new_inum.inum	= new_inode->bi_inum;
107 	dir_target	= new_inode->bi_inum;
108 
109 	if (flags & BCH_CREATE_SUBVOL) {
110 		u32 new_subvol, dir_snapshot;
111 
112 		ret = bch2_subvolume_create(trans, new_inode->bi_inum,
113 					    dir.subvol,
114 					    snapshot_src.subvol,
115 					    &new_subvol, &snapshot,
116 					    (flags & BCH_CREATE_SNAPSHOT_RO) != 0);
117 		if (ret)
118 			goto err;
119 
120 		new_inode->bi_parent_subvol	= dir.subvol;
121 		new_inode->bi_subvol		= new_subvol;
122 		new_inum.subvol			= new_subvol;
123 		dir_target			= new_subvol;
124 		dir_type			= DT_SUBVOL;
125 
126 		ret = bch2_subvolume_get_snapshot(trans, dir.subvol, &dir_snapshot);
127 		if (ret)
128 			goto err;
129 
130 		bch2_btree_iter_set_snapshot(&dir_iter, dir_snapshot);
131 		ret = bch2_btree_iter_traverse(&dir_iter);
132 		if (ret)
133 			goto err;
134 	}
135 
136 	if (!(flags & BCH_CREATE_SNAPSHOT)) {
137 		if (default_acl) {
138 			ret = bch2_set_acl_trans(trans, new_inum, new_inode,
139 						 default_acl, ACL_TYPE_DEFAULT);
140 			if (ret)
141 				goto err;
142 		}
143 
144 		if (acl) {
145 			ret = bch2_set_acl_trans(trans, new_inum, new_inode,
146 						 acl, ACL_TYPE_ACCESS);
147 			if (ret)
148 				goto err;
149 		}
150 	}
151 
152 	if (!(flags & BCH_CREATE_TMPFILE)) {
153 		struct bch_hash_info dir_hash = bch2_hash_info_init(c, dir_u);
154 		u64 dir_offset;
155 
156 		if (is_subdir_for_nlink(new_inode))
157 			dir_u->bi_nlink++;
158 		dir_u->bi_mtime = dir_u->bi_ctime = now;
159 
160 		ret =   bch2_dirent_create(trans, dir, &dir_hash,
161 					   dir_type,
162 					   name,
163 					   dir_target,
164 					   &dir_offset,
165 					   &dir_u->bi_size,
166 					   STR_HASH_must_create|BTREE_ITER_with_updates) ?:
167 			bch2_inode_write(trans, &dir_iter, dir_u);
168 		if (ret)
169 			goto err;
170 
171 		new_inode->bi_dir		= dir_u->bi_inum;
172 		new_inode->bi_dir_offset	= dir_offset;
173 	}
174 
175 	if (S_ISDIR(mode) &&
176 	    !new_inode->bi_subvol)
177 		new_inode->bi_depth = dir_u->bi_depth + 1;
178 
179 	inode_iter.flags &= ~BTREE_ITER_all_snapshots;
180 	bch2_btree_iter_set_snapshot(&inode_iter, snapshot);
181 
182 	ret   = bch2_btree_iter_traverse(&inode_iter) ?:
183 		bch2_inode_write(trans, &inode_iter, new_inode);
184 err:
185 	bch2_trans_iter_exit(trans, &inode_iter);
186 	bch2_trans_iter_exit(trans, &dir_iter);
187 	return ret;
188 }
189 
bch2_link_trans(struct btree_trans * trans,subvol_inum dir,struct bch_inode_unpacked * dir_u,subvol_inum inum,struct bch_inode_unpacked * inode_u,const struct qstr * name)190 int bch2_link_trans(struct btree_trans *trans,
191 		    subvol_inum dir,  struct bch_inode_unpacked *dir_u,
192 		    subvol_inum inum, struct bch_inode_unpacked *inode_u,
193 		    const struct qstr *name)
194 {
195 	struct bch_fs *c = trans->c;
196 	struct btree_iter dir_iter = { NULL };
197 	struct btree_iter inode_iter = { NULL };
198 	struct bch_hash_info dir_hash;
199 	u64 now = bch2_current_time(c);
200 	u64 dir_offset = 0;
201 	int ret;
202 
203 	if (dir.subvol != inum.subvol)
204 		return -EXDEV;
205 
206 	ret = bch2_inode_peek(trans, &inode_iter, inode_u, inum, BTREE_ITER_intent);
207 	if (ret)
208 		return ret;
209 
210 	inode_u->bi_ctime = now;
211 	ret = bch2_inode_nlink_inc(inode_u);
212 	if (ret)
213 		goto err;
214 
215 	ret = bch2_inode_peek(trans, &dir_iter, dir_u, dir, BTREE_ITER_intent);
216 	if (ret)
217 		goto err;
218 
219 	if (bch2_reinherit_attrs(inode_u, dir_u)) {
220 		ret = -EXDEV;
221 		goto err;
222 	}
223 
224 	dir_u->bi_mtime = dir_u->bi_ctime = now;
225 
226 	dir_hash = bch2_hash_info_init(c, dir_u);
227 
228 	ret = bch2_dirent_create(trans, dir, &dir_hash,
229 				 mode_to_type(inode_u->bi_mode),
230 				 name, inum.inum,
231 				 &dir_offset,
232 				 &dir_u->bi_size,
233 				 STR_HASH_must_create);
234 	if (ret)
235 		goto err;
236 
237 	inode_u->bi_dir		= dir.inum;
238 	inode_u->bi_dir_offset	= dir_offset;
239 
240 	ret =   bch2_inode_write(trans, &dir_iter, dir_u) ?:
241 		bch2_inode_write(trans, &inode_iter, inode_u);
242 err:
243 	bch2_trans_iter_exit(trans, &dir_iter);
244 	bch2_trans_iter_exit(trans, &inode_iter);
245 	return ret;
246 }
247 
bch2_unlink_trans(struct btree_trans * trans,subvol_inum dir,struct bch_inode_unpacked * dir_u,struct bch_inode_unpacked * inode_u,const struct qstr * name,bool deleting_subvol)248 int bch2_unlink_trans(struct btree_trans *trans,
249 		      subvol_inum dir,
250 		      struct bch_inode_unpacked *dir_u,
251 		      struct bch_inode_unpacked *inode_u,
252 		      const struct qstr *name,
253 		      bool deleting_subvol)
254 {
255 	struct bch_fs *c = trans->c;
256 	struct btree_iter dir_iter = { NULL };
257 	struct btree_iter dirent_iter = { NULL };
258 	struct btree_iter inode_iter = { NULL };
259 	struct bch_hash_info dir_hash;
260 	subvol_inum inum;
261 	u64 now = bch2_current_time(c);
262 	struct bkey_s_c k;
263 	int ret;
264 
265 	ret = bch2_inode_peek(trans, &dir_iter, dir_u, dir, BTREE_ITER_intent);
266 	if (ret)
267 		goto err;
268 
269 	dir_hash = bch2_hash_info_init(c, dir_u);
270 
271 	ret = bch2_dirent_lookup_trans(trans, &dirent_iter, dir, &dir_hash,
272 				       name, &inum, BTREE_ITER_intent);
273 	if (ret)
274 		goto err;
275 
276 	ret = bch2_inode_peek(trans, &inode_iter, inode_u, inum,
277 			      BTREE_ITER_intent);
278 	if (ret)
279 		goto err;
280 
281 	if (!deleting_subvol && S_ISDIR(inode_u->bi_mode)) {
282 		ret = bch2_empty_dir_trans(trans, inum);
283 		if (ret)
284 			goto err;
285 	}
286 
287 	if (deleting_subvol && !inode_u->bi_subvol) {
288 		ret = -BCH_ERR_ENOENT_not_subvol;
289 		goto err;
290 	}
291 
292 	if (inode_u->bi_subvol) {
293 		/* Recursive subvolume destroy not allowed (yet?) */
294 		ret = bch2_subvol_has_children(trans, inode_u->bi_subvol);
295 		if (ret)
296 			goto err;
297 	}
298 
299 	if (deleting_subvol || inode_u->bi_subvol) {
300 		ret = bch2_subvolume_unlink(trans, inode_u->bi_subvol);
301 		if (ret)
302 			goto err;
303 
304 		k = bch2_btree_iter_peek_slot(&dirent_iter);
305 		ret = bkey_err(k);
306 		if (ret)
307 			goto err;
308 
309 		/*
310 		 * If we're deleting a subvolume, we need to really delete the
311 		 * dirent, not just emit a whiteout in the current snapshot:
312 		 */
313 		bch2_btree_iter_set_snapshot(&dirent_iter, k.k->p.snapshot);
314 		ret = bch2_btree_iter_traverse(&dirent_iter);
315 		if (ret)
316 			goto err;
317 	} else {
318 		bch2_inode_nlink_dec(trans, inode_u);
319 	}
320 
321 	if (inode_u->bi_dir		== dirent_iter.pos.inode &&
322 	    inode_u->bi_dir_offset	== dirent_iter.pos.offset) {
323 		inode_u->bi_dir		= 0;
324 		inode_u->bi_dir_offset	= 0;
325 	}
326 
327 	dir_u->bi_mtime = dir_u->bi_ctime = inode_u->bi_ctime = now;
328 	dir_u->bi_nlink -= is_subdir_for_nlink(inode_u);
329 
330 	ret =   bch2_hash_delete_at(trans, bch2_dirent_hash_desc,
331 				    &dir_hash, &dirent_iter,
332 				    BTREE_UPDATE_internal_snapshot_node) ?:
333 		bch2_inode_write(trans, &dir_iter, dir_u) ?:
334 		bch2_inode_write(trans, &inode_iter, inode_u);
335 err:
336 	bch2_trans_iter_exit(trans, &inode_iter);
337 	bch2_trans_iter_exit(trans, &dirent_iter);
338 	bch2_trans_iter_exit(trans, &dir_iter);
339 	return ret;
340 }
341 
bch2_reinherit_attrs(struct bch_inode_unpacked * dst_u,struct bch_inode_unpacked * src_u)342 bool bch2_reinherit_attrs(struct bch_inode_unpacked *dst_u,
343 			  struct bch_inode_unpacked *src_u)
344 {
345 	u64 src, dst;
346 	unsigned id;
347 	bool ret = false;
348 
349 	for (id = 0; id < Inode_opt_nr; id++) {
350 		/* Skip attributes that were explicitly set on this inode */
351 		if (dst_u->bi_fields_set & (1 << id))
352 			continue;
353 
354 		src = bch2_inode_opt_get(src_u, id);
355 		dst = bch2_inode_opt_get(dst_u, id);
356 
357 		if (src == dst)
358 			continue;
359 
360 		bch2_inode_opt_set(dst_u, id, src);
361 		ret = true;
362 	}
363 
364 	return ret;
365 }
366 
subvol_update_parent(struct btree_trans * trans,u32 subvol,u32 new_parent)367 static int subvol_update_parent(struct btree_trans *trans, u32 subvol, u32 new_parent)
368 {
369 	struct btree_iter iter;
370 	struct bkey_i_subvolume *s =
371 		bch2_bkey_get_mut_typed(trans, &iter,
372 			BTREE_ID_subvolumes, POS(0, subvol),
373 			BTREE_ITER_cached, subvolume);
374 	int ret = PTR_ERR_OR_ZERO(s);
375 	if (ret)
376 		return ret;
377 
378 	s->v.fs_path_parent = cpu_to_le32(new_parent);
379 	bch2_trans_iter_exit(trans, &iter);
380 	return 0;
381 }
382 
bch2_rename_trans(struct btree_trans * trans,subvol_inum src_dir,struct bch_inode_unpacked * src_dir_u,subvol_inum dst_dir,struct bch_inode_unpacked * dst_dir_u,struct bch_inode_unpacked * src_inode_u,struct bch_inode_unpacked * dst_inode_u,const struct qstr * src_name,const struct qstr * dst_name,enum bch_rename_mode mode)383 int bch2_rename_trans(struct btree_trans *trans,
384 		      subvol_inum src_dir, struct bch_inode_unpacked *src_dir_u,
385 		      subvol_inum dst_dir, struct bch_inode_unpacked *dst_dir_u,
386 		      struct bch_inode_unpacked *src_inode_u,
387 		      struct bch_inode_unpacked *dst_inode_u,
388 		      const struct qstr *src_name,
389 		      const struct qstr *dst_name,
390 		      enum bch_rename_mode mode)
391 {
392 	struct bch_fs *c = trans->c;
393 	struct btree_iter src_dir_iter = { NULL };
394 	struct btree_iter dst_dir_iter = { NULL };
395 	struct btree_iter src_inode_iter = { NULL };
396 	struct btree_iter dst_inode_iter = { NULL };
397 	struct bch_hash_info src_hash, dst_hash;
398 	subvol_inum src_inum, dst_inum;
399 	u64 src_offset, dst_offset;
400 	u64 now = bch2_current_time(c);
401 	int ret;
402 
403 	ret = bch2_inode_peek(trans, &src_dir_iter, src_dir_u, src_dir,
404 			      BTREE_ITER_intent);
405 	if (ret)
406 		goto err;
407 
408 	src_hash = bch2_hash_info_init(c, src_dir_u);
409 
410 	if (dst_dir.inum	!= src_dir.inum ||
411 	    dst_dir.subvol	!= src_dir.subvol) {
412 		ret = bch2_inode_peek(trans, &dst_dir_iter, dst_dir_u, dst_dir,
413 				      BTREE_ITER_intent);
414 		if (ret)
415 			goto err;
416 
417 		dst_hash = bch2_hash_info_init(c, dst_dir_u);
418 	} else {
419 		dst_dir_u = src_dir_u;
420 		dst_hash = src_hash;
421 	}
422 
423 	ret = bch2_dirent_rename(trans,
424 				 src_dir, &src_hash, &src_dir_u->bi_size,
425 				 dst_dir, &dst_hash, &dst_dir_u->bi_size,
426 				 src_name, &src_inum, &src_offset,
427 				 dst_name, &dst_inum, &dst_offset,
428 				 mode);
429 	if (ret)
430 		goto err;
431 
432 	ret = bch2_inode_peek(trans, &src_inode_iter, src_inode_u, src_inum,
433 			      BTREE_ITER_intent);
434 	if (ret)
435 		goto err;
436 
437 	if (dst_inum.inum) {
438 		ret = bch2_inode_peek(trans, &dst_inode_iter, dst_inode_u, dst_inum,
439 				      BTREE_ITER_intent);
440 		if (ret)
441 			goto err;
442 	}
443 
444 	if (src_inode_u->bi_subvol &&
445 	    dst_dir.subvol != src_inode_u->bi_parent_subvol) {
446 		ret = subvol_update_parent(trans, src_inode_u->bi_subvol, dst_dir.subvol);
447 		if (ret)
448 			goto err;
449 	}
450 
451 	if (mode == BCH_RENAME_EXCHANGE &&
452 	    dst_inode_u->bi_subvol &&
453 	    src_dir.subvol != dst_inode_u->bi_parent_subvol) {
454 		ret = subvol_update_parent(trans, dst_inode_u->bi_subvol, src_dir.subvol);
455 		if (ret)
456 			goto err;
457 	}
458 
459 	/* Can't move across subvolumes, unless it's a subvolume root: */
460 	if (src_dir.subvol != dst_dir.subvol &&
461 	    (!src_inode_u->bi_subvol ||
462 	     (dst_inum.inum && !dst_inode_u->bi_subvol))) {
463 		ret = -EXDEV;
464 		goto err;
465 	}
466 
467 	if (src_inode_u->bi_parent_subvol)
468 		src_inode_u->bi_parent_subvol = dst_dir.subvol;
469 
470 	if ((mode == BCH_RENAME_EXCHANGE) &&
471 	    dst_inode_u->bi_parent_subvol)
472 		dst_inode_u->bi_parent_subvol = src_dir.subvol;
473 
474 	src_inode_u->bi_dir		= dst_dir_u->bi_inum;
475 	src_inode_u->bi_dir_offset	= dst_offset;
476 
477 	if (mode == BCH_RENAME_EXCHANGE) {
478 		dst_inode_u->bi_dir		= src_dir_u->bi_inum;
479 		dst_inode_u->bi_dir_offset	= src_offset;
480 	}
481 
482 	if (mode == BCH_RENAME_OVERWRITE &&
483 	    dst_inode_u->bi_dir		== dst_dir_u->bi_inum &&
484 	    dst_inode_u->bi_dir_offset	== src_offset) {
485 		dst_inode_u->bi_dir		= 0;
486 		dst_inode_u->bi_dir_offset	= 0;
487 	}
488 
489 	if (mode == BCH_RENAME_OVERWRITE) {
490 		if (S_ISDIR(src_inode_u->bi_mode) !=
491 		    S_ISDIR(dst_inode_u->bi_mode)) {
492 			ret = -ENOTDIR;
493 			goto err;
494 		}
495 
496 		if (S_ISDIR(dst_inode_u->bi_mode)) {
497 			ret = bch2_empty_dir_trans(trans, dst_inum);
498 			if (ret)
499 				goto err;
500 		}
501 	}
502 
503 	if (bch2_reinherit_attrs(src_inode_u, dst_dir_u) &&
504 	    S_ISDIR(src_inode_u->bi_mode)) {
505 		ret = -EXDEV;
506 		goto err;
507 	}
508 
509 	if (mode == BCH_RENAME_EXCHANGE &&
510 	    bch2_reinherit_attrs(dst_inode_u, src_dir_u) &&
511 	    S_ISDIR(dst_inode_u->bi_mode)) {
512 		ret = -EXDEV;
513 		goto err;
514 	}
515 
516 	if (is_subdir_for_nlink(src_inode_u)) {
517 		src_dir_u->bi_nlink--;
518 		dst_dir_u->bi_nlink++;
519 	}
520 
521 	if (S_ISDIR(src_inode_u->bi_mode) &&
522 	    !src_inode_u->bi_subvol)
523 		src_inode_u->bi_depth = dst_dir_u->bi_depth + 1;
524 
525 	if (mode == BCH_RENAME_EXCHANGE &&
526 	    S_ISDIR(dst_inode_u->bi_mode) &&
527 	    !dst_inode_u->bi_subvol)
528 		dst_inode_u->bi_depth = src_dir_u->bi_depth + 1;
529 
530 	if (dst_inum.inum && is_subdir_for_nlink(dst_inode_u)) {
531 		dst_dir_u->bi_nlink--;
532 		src_dir_u->bi_nlink += mode == BCH_RENAME_EXCHANGE;
533 	}
534 
535 	if (mode == BCH_RENAME_OVERWRITE)
536 		bch2_inode_nlink_dec(trans, dst_inode_u);
537 
538 	src_dir_u->bi_mtime		= now;
539 	src_dir_u->bi_ctime		= now;
540 
541 	if (src_dir.inum != dst_dir.inum) {
542 		dst_dir_u->bi_mtime	= now;
543 		dst_dir_u->bi_ctime	= now;
544 	}
545 
546 	src_inode_u->bi_ctime		= now;
547 
548 	if (dst_inum.inum)
549 		dst_inode_u->bi_ctime	= now;
550 
551 	ret =   bch2_inode_write(trans, &src_dir_iter, src_dir_u) ?:
552 		(src_dir.inum != dst_dir.inum
553 		 ? bch2_inode_write(trans, &dst_dir_iter, dst_dir_u)
554 		 : 0) ?:
555 		bch2_inode_write(trans, &src_inode_iter, src_inode_u) ?:
556 		(dst_inum.inum
557 		 ? bch2_inode_write(trans, &dst_inode_iter, dst_inode_u)
558 		 : 0);
559 err:
560 	bch2_trans_iter_exit(trans, &dst_inode_iter);
561 	bch2_trans_iter_exit(trans, &src_inode_iter);
562 	bch2_trans_iter_exit(trans, &dst_dir_iter);
563 	bch2_trans_iter_exit(trans, &src_dir_iter);
564 	return ret;
565 }
566 
567 /* inum_to_path */
568 
prt_bytes_reversed(struct printbuf * out,const void * b,unsigned n)569 static inline void prt_bytes_reversed(struct printbuf *out, const void *b, unsigned n)
570 {
571 	bch2_printbuf_make_room(out, n);
572 
573 	unsigned can_print = min(n, printbuf_remaining(out));
574 
575 	b += n;
576 
577 	for (unsigned i = 0; i < can_print; i++)
578 		out->buf[out->pos++] = *((char *) --b);
579 
580 	printbuf_nul_terminate(out);
581 }
582 
prt_str_reversed(struct printbuf * out,const char * s)583 static inline void prt_str_reversed(struct printbuf *out, const char *s)
584 {
585 	prt_bytes_reversed(out, s, strlen(s));
586 }
587 
reverse_bytes(void * b,size_t n)588 static inline void reverse_bytes(void *b, size_t n)
589 {
590 	char *e = b + n, *s = b;
591 
592 	while (s < e) {
593 		--e;
594 		swap(*s, *e);
595 		s++;
596 	}
597 }
598 
599 /* XXX: we don't yet attempt to print paths when we don't know the subvol */
bch2_inum_to_path(struct btree_trans * trans,subvol_inum inum,struct printbuf * path)600 int bch2_inum_to_path(struct btree_trans *trans, subvol_inum inum, struct printbuf *path)
601 {
602 	unsigned orig_pos = path->pos;
603 	int ret = 0;
604 
605 	while (!(inum.subvol == BCACHEFS_ROOT_SUBVOL &&
606 		 inum.inum   == BCACHEFS_ROOT_INO)) {
607 		struct bch_inode_unpacked inode;
608 		ret = bch2_inode_find_by_inum_trans(trans, inum, &inode);
609 		if (ret)
610 			goto disconnected;
611 
612 		if (!inode.bi_dir && !inode.bi_dir_offset) {
613 			ret = -BCH_ERR_ENOENT_inode_no_backpointer;
614 			goto disconnected;
615 		}
616 
617 		inum.subvol	= inode.bi_parent_subvol ?: inum.subvol;
618 		inum.inum	= inode.bi_dir;
619 
620 		u32 snapshot;
621 		ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
622 		if (ret)
623 			goto disconnected;
624 
625 		struct btree_iter d_iter;
626 		struct bkey_s_c_dirent d = bch2_bkey_get_iter_typed(trans, &d_iter,
627 				BTREE_ID_dirents, SPOS(inode.bi_dir, inode.bi_dir_offset, snapshot),
628 				0, dirent);
629 		ret = bkey_err(d.s_c);
630 		if (ret)
631 			goto disconnected;
632 
633 		struct qstr dirent_name = bch2_dirent_get_name(d);
634 		prt_bytes_reversed(path, dirent_name.name, dirent_name.len);
635 
636 		prt_char(path, '/');
637 
638 		bch2_trans_iter_exit(trans, &d_iter);
639 	}
640 
641 	if (orig_pos == path->pos)
642 		prt_char(path, '/');
643 out:
644 	ret = path->allocation_failure ? -ENOMEM : 0;
645 	if (ret)
646 		goto err;
647 
648 	reverse_bytes(path->buf + orig_pos, path->pos - orig_pos);
649 	return 0;
650 err:
651 	return ret;
652 disconnected:
653 	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
654 		goto err;
655 
656 	prt_str_reversed(path, "(disconnected)");
657 	goto out;
658 }
659 
660 /* fsck */
661 
bch2_check_dirent_inode_dirent(struct btree_trans * trans,struct bkey_s_c_dirent d,struct bch_inode_unpacked * target,bool in_fsck)662 static int bch2_check_dirent_inode_dirent(struct btree_trans *trans,
663 					  struct bkey_s_c_dirent d,
664 					  struct bch_inode_unpacked *target,
665 					  bool in_fsck)
666 {
667 	struct bch_fs *c = trans->c;
668 	struct printbuf buf = PRINTBUF;
669 	struct btree_iter bp_iter = { NULL };
670 	int ret = 0;
671 
672 	if (inode_points_to_dirent(target, d))
673 		return 0;
674 
675 	if (!target->bi_dir &&
676 	    !target->bi_dir_offset) {
677 		fsck_err_on(S_ISDIR(target->bi_mode),
678 			    trans, inode_dir_missing_backpointer,
679 			    "directory with missing backpointer\n%s",
680 			    (printbuf_reset(&buf),
681 			     bch2_bkey_val_to_text(&buf, c, d.s_c),
682 			     prt_printf(&buf, "\n"),
683 			     bch2_inode_unpacked_to_text(&buf, target),
684 			     buf.buf));
685 
686 		fsck_err_on(target->bi_flags & BCH_INODE_unlinked,
687 			    trans, inode_unlinked_but_has_dirent,
688 			    "inode unlinked but has dirent\n%s",
689 			    (printbuf_reset(&buf),
690 			     bch2_bkey_val_to_text(&buf, c, d.s_c),
691 			     prt_printf(&buf, "\n"),
692 			     bch2_inode_unpacked_to_text(&buf, target),
693 			     buf.buf));
694 
695 		target->bi_flags &= ~BCH_INODE_unlinked;
696 		target->bi_dir		= d.k->p.inode;
697 		target->bi_dir_offset	= d.k->p.offset;
698 		return __bch2_fsck_write_inode(trans, target);
699 	}
700 
701 	if (bch2_inode_should_have_single_bp(target) &&
702 	    !fsck_err(trans, inode_wrong_backpointer,
703 		      "dirent points to inode that does not point back:\n  %s",
704 		      (bch2_bkey_val_to_text(&buf, c, d.s_c),
705 		       prt_printf(&buf, "\n  "),
706 		       bch2_inode_unpacked_to_text(&buf, target),
707 		       buf.buf)))
708 		goto err;
709 
710 	struct bkey_s_c_dirent bp_dirent =
711 		bch2_bkey_get_iter_typed(trans, &bp_iter, BTREE_ID_dirents,
712 			      SPOS(target->bi_dir, target->bi_dir_offset, target->bi_snapshot),
713 			      0, dirent);
714 	ret = bkey_err(bp_dirent);
715 	if (ret && !bch2_err_matches(ret, ENOENT))
716 		goto err;
717 
718 	bool backpointer_exists = !ret;
719 	ret = 0;
720 
721 	if (!backpointer_exists) {
722 		if (fsck_err(trans, inode_wrong_backpointer,
723 			     "inode %llu:%u has wrong backpointer:\n"
724 			     "got       %llu:%llu\n"
725 			     "should be %llu:%llu",
726 			     target->bi_inum, target->bi_snapshot,
727 			     target->bi_dir,
728 			     target->bi_dir_offset,
729 			     d.k->p.inode,
730 			     d.k->p.offset)) {
731 			target->bi_dir		= d.k->p.inode;
732 			target->bi_dir_offset	= d.k->p.offset;
733 			ret = __bch2_fsck_write_inode(trans, target);
734 		}
735 	} else {
736 		bch2_bkey_val_to_text(&buf, c, d.s_c);
737 		prt_newline(&buf);
738 		bch2_bkey_val_to_text(&buf, c, bp_dirent.s_c);
739 
740 		if (S_ISDIR(target->bi_mode) || target->bi_subvol) {
741 			/*
742 			 * XXX: verify connectivity of the other dirent
743 			 * up to the root before removing this one
744 			 *
745 			 * Additionally, bch2_lookup would need to cope with the
746 			 * dirent it found being removed - or should we remove
747 			 * the other one, even though the inode points to it?
748 			 */
749 			if (in_fsck) {
750 				if (fsck_err(trans, inode_dir_multiple_links,
751 					     "%s %llu:%u with multiple links\n%s",
752 					     S_ISDIR(target->bi_mode) ? "directory" : "subvolume",
753 					     target->bi_inum, target->bi_snapshot, buf.buf))
754 					ret = bch2_fsck_remove_dirent(trans, d.k->p);
755 			} else {
756 				bch2_fs_inconsistent(c,
757 						"%s %llu:%u with multiple links\n%s",
758 						S_ISDIR(target->bi_mode) ? "directory" : "subvolume",
759 						target->bi_inum, target->bi_snapshot, buf.buf);
760 			}
761 
762 			goto out;
763 		} else {
764 			/*
765 			 * hardlinked file with nlink 0:
766 			 * We're just adjusting nlink here so check_nlinks() will pick
767 			 * it up, it ignores inodes with nlink 0
768 			 */
769 			if (fsck_err_on(!target->bi_nlink,
770 					trans, inode_multiple_links_but_nlink_0,
771 					"inode %llu:%u type %s has multiple links but i_nlink 0\n%s",
772 					target->bi_inum, target->bi_snapshot, bch2_d_types[d.v->d_type], buf.buf)) {
773 				target->bi_nlink++;
774 				target->bi_flags &= ~BCH_INODE_unlinked;
775 				ret = __bch2_fsck_write_inode(trans, target);
776 				if (ret)
777 					goto err;
778 			}
779 		}
780 	}
781 out:
782 err:
783 fsck_err:
784 	bch2_trans_iter_exit(trans, &bp_iter);
785 	printbuf_exit(&buf);
786 	bch_err_fn(c, ret);
787 	return ret;
788 }
789 
__bch2_check_dirent_target(struct btree_trans * trans,struct btree_iter * dirent_iter,struct bkey_s_c_dirent d,struct bch_inode_unpacked * target,bool in_fsck)790 int __bch2_check_dirent_target(struct btree_trans *trans,
791 			       struct btree_iter *dirent_iter,
792 			       struct bkey_s_c_dirent d,
793 			       struct bch_inode_unpacked *target,
794 			       bool in_fsck)
795 {
796 	struct bch_fs *c = trans->c;
797 	struct printbuf buf = PRINTBUF;
798 	int ret = 0;
799 
800 	ret = bch2_check_dirent_inode_dirent(trans, d, target, in_fsck);
801 	if (ret)
802 		goto err;
803 
804 	if (fsck_err_on(d.v->d_type != inode_d_type(target),
805 			trans, dirent_d_type_wrong,
806 			"incorrect d_type: got %s, should be %s:\n%s",
807 			bch2_d_type_str(d.v->d_type),
808 			bch2_d_type_str(inode_d_type(target)),
809 			(printbuf_reset(&buf),
810 			 bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf))) {
811 		struct bkey_i_dirent *n = bch2_trans_kmalloc(trans, bkey_bytes(d.k));
812 		ret = PTR_ERR_OR_ZERO(n);
813 		if (ret)
814 			goto err;
815 
816 		bkey_reassemble(&n->k_i, d.s_c);
817 		n->v.d_type = inode_d_type(target);
818 		if (n->v.d_type == DT_SUBVOL) {
819 			n->v.d_parent_subvol = cpu_to_le32(target->bi_parent_subvol);
820 			n->v.d_child_subvol = cpu_to_le32(target->bi_subvol);
821 		} else {
822 			n->v.d_inum = cpu_to_le64(target->bi_inum);
823 		}
824 
825 		ret = bch2_trans_update(trans, dirent_iter, &n->k_i, 0);
826 		if (ret)
827 			goto err;
828 	}
829 err:
830 fsck_err:
831 	printbuf_exit(&buf);
832 	bch_err_fn(c, ret);
833 	return ret;
834 }
835