1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2007,2008 Oracle. All rights reserved. |
4 | */ |
5 | |
6 | #include <linux/sched.h> |
7 | #include <linux/slab.h> |
8 | #include <linux/rbtree.h> |
9 | #include <linux/mm.h> |
10 | #include <linux/error-injection.h> |
11 | #include "messages.h" |
12 | #include "ctree.h" |
13 | #include "disk-io.h" |
14 | #include "transaction.h" |
15 | #include "print-tree.h" |
16 | #include "locking.h" |
17 | #include "volumes.h" |
18 | #include "qgroup.h" |
19 | #include "tree-mod-log.h" |
20 | #include "tree-checker.h" |
21 | #include "fs.h" |
22 | #include "accessors.h" |
23 | #include "extent-tree.h" |
24 | #include "relocation.h" |
25 | #include "file-item.h" |
26 | |
27 | static struct kmem_cache *btrfs_path_cachep; |
28 | |
29 | static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
30 | *root, struct btrfs_path *path, int level); |
31 | static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
32 | const struct btrfs_key *ins_key, struct btrfs_path *path, |
33 | int data_size, int extend); |
34 | static int push_node_left(struct btrfs_trans_handle *trans, |
35 | struct extent_buffer *dst, |
36 | struct extent_buffer *src, int empty); |
37 | static int balance_node_right(struct btrfs_trans_handle *trans, |
38 | struct extent_buffer *dst_buf, |
39 | struct extent_buffer *src_buf); |
40 | |
41 | static const struct btrfs_csums { |
42 | u16 size; |
43 | const char name[10]; |
44 | const char driver[12]; |
45 | } btrfs_csums[] = { |
46 | [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" }, |
47 | [BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" }, |
48 | [BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" }, |
49 | [BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b" , |
50 | .driver = "blake2b-256" }, |
51 | }; |
52 | |
53 | /* |
54 | * The leaf data grows from end-to-front in the node. this returns the address |
55 | * of the start of the last item, which is the stop of the leaf data stack. |
56 | */ |
57 | static unsigned int leaf_data_end(const struct extent_buffer *leaf) |
58 | { |
59 | u32 nr = btrfs_header_nritems(eb: leaf); |
60 | |
61 | if (nr == 0) |
62 | return BTRFS_LEAF_DATA_SIZE(info: leaf->fs_info); |
63 | return btrfs_item_offset(eb: leaf, slot: nr - 1); |
64 | } |
65 | |
66 | /* |
67 | * Move data in a @leaf (using memmove, safe for overlapping ranges). |
68 | * |
69 | * @leaf: leaf that we're doing a memmove on |
70 | * @dst_offset: item data offset we're moving to |
71 | * @src_offset: item data offset were' moving from |
72 | * @len: length of the data we're moving |
73 | * |
74 | * Wrapper around memmove_extent_buffer() that takes into account the header on |
75 | * the leaf. The btrfs_item offset's start directly after the header, so we |
76 | * have to adjust any offsets to account for the header in the leaf. This |
77 | * handles that math to simplify the callers. |
78 | */ |
79 | static inline void memmove_leaf_data(const struct extent_buffer *leaf, |
80 | unsigned long dst_offset, |
81 | unsigned long src_offset, |
82 | unsigned long len) |
83 | { |
84 | memmove_extent_buffer(dst: leaf, dst_offset: btrfs_item_nr_offset(eb: leaf, nr: 0) + dst_offset, |
85 | src_offset: btrfs_item_nr_offset(eb: leaf, nr: 0) + src_offset, len); |
86 | } |
87 | |
88 | /* |
89 | * Copy item data from @src into @dst at the given @offset. |
90 | * |
91 | * @dst: destination leaf that we're copying into |
92 | * @src: source leaf that we're copying from |
93 | * @dst_offset: item data offset we're copying to |
94 | * @src_offset: item data offset were' copying from |
95 | * @len: length of the data we're copying |
96 | * |
97 | * Wrapper around copy_extent_buffer() that takes into account the header on |
98 | * the leaf. The btrfs_item offset's start directly after the header, so we |
99 | * have to adjust any offsets to account for the header in the leaf. This |
100 | * handles that math to simplify the callers. |
101 | */ |
102 | static inline void copy_leaf_data(const struct extent_buffer *dst, |
103 | const struct extent_buffer *src, |
104 | unsigned long dst_offset, |
105 | unsigned long src_offset, unsigned long len) |
106 | { |
107 | copy_extent_buffer(dst, src, dst_offset: btrfs_item_nr_offset(eb: dst, nr: 0) + dst_offset, |
108 | src_offset: btrfs_item_nr_offset(eb: src, nr: 0) + src_offset, len); |
109 | } |
110 | |
111 | /* |
112 | * Move items in a @leaf (using memmove). |
113 | * |
114 | * @dst: destination leaf for the items |
115 | * @dst_item: the item nr we're copying into |
116 | * @src_item: the item nr we're copying from |
117 | * @nr_items: the number of items to copy |
118 | * |
119 | * Wrapper around memmove_extent_buffer() that does the math to get the |
120 | * appropriate offsets into the leaf from the item numbers. |
121 | */ |
122 | static inline void memmove_leaf_items(const struct extent_buffer *leaf, |
123 | int dst_item, int src_item, int nr_items) |
124 | { |
125 | memmove_extent_buffer(dst: leaf, dst_offset: btrfs_item_nr_offset(eb: leaf, nr: dst_item), |
126 | src_offset: btrfs_item_nr_offset(eb: leaf, nr: src_item), |
127 | len: nr_items * sizeof(struct btrfs_item)); |
128 | } |
129 | |
130 | /* |
131 | * Copy items from @src into @dst at the given @offset. |
132 | * |
133 | * @dst: destination leaf for the items |
134 | * @src: source leaf for the items |
135 | * @dst_item: the item nr we're copying into |
136 | * @src_item: the item nr we're copying from |
137 | * @nr_items: the number of items to copy |
138 | * |
139 | * Wrapper around copy_extent_buffer() that does the math to get the |
140 | * appropriate offsets into the leaf from the item numbers. |
141 | */ |
142 | static inline void copy_leaf_items(const struct extent_buffer *dst, |
143 | const struct extent_buffer *src, |
144 | int dst_item, int src_item, int nr_items) |
145 | { |
146 | copy_extent_buffer(dst, src, dst_offset: btrfs_item_nr_offset(eb: dst, nr: dst_item), |
147 | src_offset: btrfs_item_nr_offset(eb: src, nr: src_item), |
148 | len: nr_items * sizeof(struct btrfs_item)); |
149 | } |
150 | |
151 | /* This exists for btrfs-progs usages. */ |
152 | u16 btrfs_csum_type_size(u16 type) |
153 | { |
154 | return btrfs_csums[type].size; |
155 | } |
156 | |
157 | int btrfs_super_csum_size(const struct btrfs_super_block *s) |
158 | { |
159 | u16 t = btrfs_super_csum_type(s); |
160 | /* |
161 | * csum type is validated at mount time |
162 | */ |
163 | return btrfs_csum_type_size(type: t); |
164 | } |
165 | |
166 | const char *btrfs_super_csum_name(u16 csum_type) |
167 | { |
168 | /* csum type is validated at mount time */ |
169 | return btrfs_csums[csum_type].name; |
170 | } |
171 | |
172 | /* |
173 | * Return driver name if defined, otherwise the name that's also a valid driver |
174 | * name |
175 | */ |
176 | const char *btrfs_super_csum_driver(u16 csum_type) |
177 | { |
178 | /* csum type is validated at mount time */ |
179 | return btrfs_csums[csum_type].driver[0] ? |
180 | btrfs_csums[csum_type].driver : |
181 | btrfs_csums[csum_type].name; |
182 | } |
183 | |
184 | size_t __attribute_const__ btrfs_get_num_csums(void) |
185 | { |
186 | return ARRAY_SIZE(btrfs_csums); |
187 | } |
188 | |
189 | struct btrfs_path *btrfs_alloc_path(void) |
190 | { |
191 | might_sleep(); |
192 | |
193 | return kmem_cache_zalloc(k: btrfs_path_cachep, GFP_NOFS); |
194 | } |
195 | |
196 | /* this also releases the path */ |
197 | void btrfs_free_path(struct btrfs_path *p) |
198 | { |
199 | if (!p) |
200 | return; |
201 | btrfs_release_path(p); |
202 | kmem_cache_free(s: btrfs_path_cachep, objp: p); |
203 | } |
204 | |
205 | /* |
206 | * path release drops references on the extent buffers in the path |
207 | * and it drops any locks held by this path |
208 | * |
209 | * It is safe to call this on paths that no locks or extent buffers held. |
210 | */ |
211 | noinline void btrfs_release_path(struct btrfs_path *p) |
212 | { |
213 | int i; |
214 | |
215 | for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
216 | p->slots[i] = 0; |
217 | if (!p->nodes[i]) |
218 | continue; |
219 | if (p->locks[i]) { |
220 | btrfs_tree_unlock_rw(eb: p->nodes[i], rw: p->locks[i]); |
221 | p->locks[i] = 0; |
222 | } |
223 | free_extent_buffer(eb: p->nodes[i]); |
224 | p->nodes[i] = NULL; |
225 | } |
226 | } |
227 | |
228 | /* |
229 | * We want the transaction abort to print stack trace only for errors where the |
230 | * cause could be a bug, eg. due to ENOSPC, and not for common errors that are |
231 | * caused by external factors. |
232 | */ |
233 | bool __cold abort_should_print_stack(int error) |
234 | { |
235 | switch (error) { |
236 | case -EIO: |
237 | case -EROFS: |
238 | case -ENOMEM: |
239 | return false; |
240 | } |
241 | return true; |
242 | } |
243 | |
244 | /* |
245 | * safely gets a reference on the root node of a tree. A lock |
246 | * is not taken, so a concurrent writer may put a different node |
247 | * at the root of the tree. See btrfs_lock_root_node for the |
248 | * looping required. |
249 | * |
250 | * The extent buffer returned by this has a reference taken, so |
251 | * it won't disappear. It may stop being the root of the tree |
252 | * at any time because there are no locks held. |
253 | */ |
254 | struct extent_buffer *btrfs_root_node(struct btrfs_root *root) |
255 | { |
256 | struct extent_buffer *eb; |
257 | |
258 | while (1) { |
259 | rcu_read_lock(); |
260 | eb = rcu_dereference(root->node); |
261 | |
262 | /* |
263 | * RCU really hurts here, we could free up the root node because |
264 | * it was COWed but we may not get the new root node yet so do |
265 | * the inc_not_zero dance and if it doesn't work then |
266 | * synchronize_rcu and try again. |
267 | */ |
268 | if (atomic_inc_not_zero(v: &eb->refs)) { |
269 | rcu_read_unlock(); |
270 | break; |
271 | } |
272 | rcu_read_unlock(); |
273 | synchronize_rcu(); |
274 | } |
275 | return eb; |
276 | } |
277 | |
278 | /* |
279 | * Cowonly root (not-shareable trees, everything not subvolume or reloc roots), |
280 | * just get put onto a simple dirty list. Transaction walks this list to make |
281 | * sure they get properly updated on disk. |
282 | */ |
283 | static void add_root_to_dirty_list(struct btrfs_root *root) |
284 | { |
285 | struct btrfs_fs_info *fs_info = root->fs_info; |
286 | |
287 | if (test_bit(BTRFS_ROOT_DIRTY, &root->state) || |
288 | !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state)) |
289 | return; |
290 | |
291 | spin_lock(lock: &fs_info->trans_lock); |
292 | if (!test_and_set_bit(nr: BTRFS_ROOT_DIRTY, addr: &root->state)) { |
293 | /* Want the extent tree to be the last on the list */ |
294 | if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID) |
295 | list_move_tail(list: &root->dirty_list, |
296 | head: &fs_info->dirty_cowonly_roots); |
297 | else |
298 | list_move(list: &root->dirty_list, |
299 | head: &fs_info->dirty_cowonly_roots); |
300 | } |
301 | spin_unlock(lock: &fs_info->trans_lock); |
302 | } |
303 | |
304 | /* |
305 | * used by snapshot creation to make a copy of a root for a tree with |
306 | * a given objectid. The buffer with the new root node is returned in |
307 | * cow_ret, and this func returns zero on success or a negative error code. |
308 | */ |
309 | int btrfs_copy_root(struct btrfs_trans_handle *trans, |
310 | struct btrfs_root *root, |
311 | struct extent_buffer *buf, |
312 | struct extent_buffer **cow_ret, u64 new_root_objectid) |
313 | { |
314 | struct btrfs_fs_info *fs_info = root->fs_info; |
315 | struct extent_buffer *cow; |
316 | int ret = 0; |
317 | int level; |
318 | struct btrfs_disk_key disk_key; |
319 | u64 reloc_src_root = 0; |
320 | |
321 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
322 | trans->transid != fs_info->running_transaction->transid); |
323 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
324 | trans->transid != root->last_trans); |
325 | |
326 | level = btrfs_header_level(eb: buf); |
327 | if (level == 0) |
328 | btrfs_item_key(eb: buf, disk_key: &disk_key, nr: 0); |
329 | else |
330 | btrfs_node_key(eb: buf, disk_key: &disk_key, nr: 0); |
331 | |
332 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
333 | reloc_src_root = btrfs_header_owner(eb: buf); |
334 | cow = btrfs_alloc_tree_block(trans, root, parent: 0, root_objectid: new_root_objectid, |
335 | key: &disk_key, level, hint: buf->start, empty_size: 0, |
336 | reloc_src_root, nest: BTRFS_NESTING_NEW_ROOT); |
337 | if (IS_ERR(ptr: cow)) |
338 | return PTR_ERR(ptr: cow); |
339 | |
340 | copy_extent_buffer_full(dst: cow, src: buf); |
341 | btrfs_set_header_bytenr(eb: cow, val: cow->start); |
342 | btrfs_set_header_generation(eb: cow, val: trans->transid); |
343 | btrfs_set_header_backref_rev(eb: cow, BTRFS_MIXED_BACKREF_REV); |
344 | btrfs_clear_header_flag(eb: cow, BTRFS_HEADER_FLAG_WRITTEN | |
345 | BTRFS_HEADER_FLAG_RELOC); |
346 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
347 | btrfs_set_header_flag(eb: cow, BTRFS_HEADER_FLAG_RELOC); |
348 | else |
349 | btrfs_set_header_owner(eb: cow, val: new_root_objectid); |
350 | |
351 | write_extent_buffer_fsid(eb: cow, fsid: fs_info->fs_devices->metadata_uuid); |
352 | |
353 | WARN_ON(btrfs_header_generation(buf) > trans->transid); |
354 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
355 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 1); |
356 | else |
357 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 0); |
358 | if (ret) { |
359 | btrfs_tree_unlock(eb: cow); |
360 | free_extent_buffer(eb: cow); |
361 | btrfs_abort_transaction(trans, ret); |
362 | return ret; |
363 | } |
364 | |
365 | btrfs_mark_buffer_dirty(trans, buf: cow); |
366 | *cow_ret = cow; |
367 | return 0; |
368 | } |
369 | |
370 | /* |
371 | * check if the tree block can be shared by multiple trees |
372 | */ |
373 | int btrfs_block_can_be_shared(struct btrfs_trans_handle *trans, |
374 | struct btrfs_root *root, |
375 | struct extent_buffer *buf) |
376 | { |
377 | /* |
378 | * Tree blocks not in shareable trees and tree roots are never shared. |
379 | * If a block was allocated after the last snapshot and the block was |
380 | * not allocated by tree relocation, we know the block is not shared. |
381 | */ |
382 | if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
383 | buf != root->node && |
384 | (btrfs_header_generation(eb: buf) <= |
385 | btrfs_root_last_snapshot(s: &root->root_item) || |
386 | btrfs_header_flag(eb: buf, BTRFS_HEADER_FLAG_RELOC))) { |
387 | if (buf != root->commit_root) |
388 | return 1; |
389 | /* |
390 | * An extent buffer that used to be the commit root may still be |
391 | * shared because the tree height may have increased and it |
392 | * became a child of a higher level root. This can happen when |
393 | * snapshotting a subvolume created in the current transaction. |
394 | */ |
395 | if (btrfs_header_generation(eb: buf) == trans->transid) |
396 | return 1; |
397 | } |
398 | |
399 | return 0; |
400 | } |
401 | |
402 | static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, |
403 | struct btrfs_root *root, |
404 | struct extent_buffer *buf, |
405 | struct extent_buffer *cow, |
406 | int *last_ref) |
407 | { |
408 | struct btrfs_fs_info *fs_info = root->fs_info; |
409 | u64 refs; |
410 | u64 owner; |
411 | u64 flags; |
412 | u64 new_flags = 0; |
413 | int ret; |
414 | |
415 | /* |
416 | * Backrefs update rules: |
417 | * |
418 | * Always use full backrefs for extent pointers in tree block |
419 | * allocated by tree relocation. |
420 | * |
421 | * If a shared tree block is no longer referenced by its owner |
422 | * tree (btrfs_header_owner(buf) == root->root_key.objectid), |
423 | * use full backrefs for extent pointers in tree block. |
424 | * |
425 | * If a tree block is been relocating |
426 | * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), |
427 | * use full backrefs for extent pointers in tree block. |
428 | * The reason for this is some operations (such as drop tree) |
429 | * are only allowed for blocks use full backrefs. |
430 | */ |
431 | |
432 | if (btrfs_block_can_be_shared(trans, root, buf)) { |
433 | ret = btrfs_lookup_extent_info(trans, fs_info, bytenr: buf->start, |
434 | offset: btrfs_header_level(eb: buf), metadata: 1, |
435 | refs: &refs, flags: &flags); |
436 | if (ret) |
437 | return ret; |
438 | if (unlikely(refs == 0)) { |
439 | btrfs_crit(fs_info, |
440 | "found 0 references for tree block at bytenr %llu level %d root %llu" , |
441 | buf->start, btrfs_header_level(buf), |
442 | btrfs_root_id(root)); |
443 | ret = -EUCLEAN; |
444 | btrfs_abort_transaction(trans, ret); |
445 | return ret; |
446 | } |
447 | } else { |
448 | refs = 1; |
449 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
450 | btrfs_header_backref_rev(eb: buf) < BTRFS_MIXED_BACKREF_REV) |
451 | flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; |
452 | else |
453 | flags = 0; |
454 | } |
455 | |
456 | owner = btrfs_header_owner(eb: buf); |
457 | BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && |
458 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); |
459 | |
460 | if (refs > 1) { |
461 | if ((owner == root->root_key.objectid || |
462 | root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && |
463 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
464 | ret = btrfs_inc_ref(trans, root, buf, full_backref: 1); |
465 | if (ret) |
466 | return ret; |
467 | |
468 | if (root->root_key.objectid == |
469 | BTRFS_TREE_RELOC_OBJECTID) { |
470 | ret = btrfs_dec_ref(trans, root, buf, full_backref: 0); |
471 | if (ret) |
472 | return ret; |
473 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 1); |
474 | if (ret) |
475 | return ret; |
476 | } |
477 | new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; |
478 | } else { |
479 | |
480 | if (root->root_key.objectid == |
481 | BTRFS_TREE_RELOC_OBJECTID) |
482 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 1); |
483 | else |
484 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 0); |
485 | if (ret) |
486 | return ret; |
487 | } |
488 | if (new_flags != 0) { |
489 | ret = btrfs_set_disk_extent_flags(trans, eb: buf, flags: new_flags); |
490 | if (ret) |
491 | return ret; |
492 | } |
493 | } else { |
494 | if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { |
495 | if (root->root_key.objectid == |
496 | BTRFS_TREE_RELOC_OBJECTID) |
497 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 1); |
498 | else |
499 | ret = btrfs_inc_ref(trans, root, buf: cow, full_backref: 0); |
500 | if (ret) |
501 | return ret; |
502 | ret = btrfs_dec_ref(trans, root, buf, full_backref: 1); |
503 | if (ret) |
504 | return ret; |
505 | } |
506 | btrfs_clear_buffer_dirty(trans, buf); |
507 | *last_ref = 1; |
508 | } |
509 | return 0; |
510 | } |
511 | |
512 | /* |
513 | * does the dirty work in cow of a single block. The parent block (if |
514 | * supplied) is updated to point to the new cow copy. The new buffer is marked |
515 | * dirty and returned locked. If you modify the block it needs to be marked |
516 | * dirty again. |
517 | * |
518 | * search_start -- an allocation hint for the new block |
519 | * |
520 | * empty_size -- a hint that you plan on doing more cow. This is the size in |
521 | * bytes the allocator should try to find free next to the block it returns. |
522 | * This is just a hint and may be ignored by the allocator. |
523 | */ |
524 | int btrfs_force_cow_block(struct btrfs_trans_handle *trans, |
525 | struct btrfs_root *root, |
526 | struct extent_buffer *buf, |
527 | struct extent_buffer *parent, int parent_slot, |
528 | struct extent_buffer **cow_ret, |
529 | u64 search_start, u64 empty_size, |
530 | enum btrfs_lock_nesting nest) |
531 | { |
532 | struct btrfs_fs_info *fs_info = root->fs_info; |
533 | struct btrfs_disk_key disk_key; |
534 | struct extent_buffer *cow; |
535 | int level, ret; |
536 | int last_ref = 0; |
537 | int unlock_orig = 0; |
538 | u64 parent_start = 0; |
539 | u64 reloc_src_root = 0; |
540 | |
541 | if (*cow_ret == buf) |
542 | unlock_orig = 1; |
543 | |
544 | btrfs_assert_tree_write_locked(eb: buf); |
545 | |
546 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
547 | trans->transid != fs_info->running_transaction->transid); |
548 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
549 | trans->transid != root->last_trans); |
550 | |
551 | level = btrfs_header_level(eb: buf); |
552 | |
553 | if (level == 0) |
554 | btrfs_item_key(eb: buf, disk_key: &disk_key, nr: 0); |
555 | else |
556 | btrfs_node_key(eb: buf, disk_key: &disk_key, nr: 0); |
557 | |
558 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { |
559 | if (parent) |
560 | parent_start = parent->start; |
561 | reloc_src_root = btrfs_header_owner(eb: buf); |
562 | } |
563 | cow = btrfs_alloc_tree_block(trans, root, parent: parent_start, |
564 | root_objectid: root->root_key.objectid, key: &disk_key, level, |
565 | hint: search_start, empty_size, reloc_src_root, nest); |
566 | if (IS_ERR(ptr: cow)) |
567 | return PTR_ERR(ptr: cow); |
568 | |
569 | /* cow is set to blocking by btrfs_init_new_buffer */ |
570 | |
571 | copy_extent_buffer_full(dst: cow, src: buf); |
572 | btrfs_set_header_bytenr(eb: cow, val: cow->start); |
573 | btrfs_set_header_generation(eb: cow, val: trans->transid); |
574 | btrfs_set_header_backref_rev(eb: cow, BTRFS_MIXED_BACKREF_REV); |
575 | btrfs_clear_header_flag(eb: cow, BTRFS_HEADER_FLAG_WRITTEN | |
576 | BTRFS_HEADER_FLAG_RELOC); |
577 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
578 | btrfs_set_header_flag(eb: cow, BTRFS_HEADER_FLAG_RELOC); |
579 | else |
580 | btrfs_set_header_owner(eb: cow, val: root->root_key.objectid); |
581 | |
582 | write_extent_buffer_fsid(eb: cow, fsid: fs_info->fs_devices->metadata_uuid); |
583 | |
584 | ret = update_ref_for_cow(trans, root, buf, cow, last_ref: &last_ref); |
585 | if (ret) { |
586 | btrfs_tree_unlock(eb: cow); |
587 | free_extent_buffer(eb: cow); |
588 | btrfs_abort_transaction(trans, ret); |
589 | return ret; |
590 | } |
591 | |
592 | if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { |
593 | ret = btrfs_reloc_cow_block(trans, root, buf, cow); |
594 | if (ret) { |
595 | btrfs_tree_unlock(eb: cow); |
596 | free_extent_buffer(eb: cow); |
597 | btrfs_abort_transaction(trans, ret); |
598 | return ret; |
599 | } |
600 | } |
601 | |
602 | if (buf == root->node) { |
603 | WARN_ON(parent && parent != buf); |
604 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
605 | btrfs_header_backref_rev(eb: buf) < BTRFS_MIXED_BACKREF_REV) |
606 | parent_start = buf->start; |
607 | |
608 | ret = btrfs_tree_mod_log_insert_root(old_root: root->node, new_root: cow, log_removal: true); |
609 | if (ret < 0) { |
610 | btrfs_tree_unlock(eb: cow); |
611 | free_extent_buffer(eb: cow); |
612 | btrfs_abort_transaction(trans, ret); |
613 | return ret; |
614 | } |
615 | atomic_inc(v: &cow->refs); |
616 | rcu_assign_pointer(root->node, cow); |
617 | |
618 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf, |
619 | parent: parent_start, last_ref); |
620 | free_extent_buffer(eb: buf); |
621 | add_root_to_dirty_list(root); |
622 | } else { |
623 | WARN_ON(trans->transid != btrfs_header_generation(parent)); |
624 | ret = btrfs_tree_mod_log_insert_key(eb: parent, slot: parent_slot, |
625 | op: BTRFS_MOD_LOG_KEY_REPLACE); |
626 | if (ret) { |
627 | btrfs_tree_unlock(eb: cow); |
628 | free_extent_buffer(eb: cow); |
629 | btrfs_abort_transaction(trans, ret); |
630 | return ret; |
631 | } |
632 | btrfs_set_node_blockptr(eb: parent, nr: parent_slot, |
633 | val: cow->start); |
634 | btrfs_set_node_ptr_generation(eb: parent, nr: parent_slot, |
635 | val: trans->transid); |
636 | btrfs_mark_buffer_dirty(trans, buf: parent); |
637 | if (last_ref) { |
638 | ret = btrfs_tree_mod_log_free_eb(eb: buf); |
639 | if (ret) { |
640 | btrfs_tree_unlock(eb: cow); |
641 | free_extent_buffer(eb: cow); |
642 | btrfs_abort_transaction(trans, ret); |
643 | return ret; |
644 | } |
645 | } |
646 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf, |
647 | parent: parent_start, last_ref); |
648 | } |
649 | if (unlock_orig) |
650 | btrfs_tree_unlock(eb: buf); |
651 | free_extent_buffer_stale(eb: buf); |
652 | btrfs_mark_buffer_dirty(trans, buf: cow); |
653 | *cow_ret = cow; |
654 | return 0; |
655 | } |
656 | |
657 | static inline int should_cow_block(struct btrfs_trans_handle *trans, |
658 | struct btrfs_root *root, |
659 | struct extent_buffer *buf) |
660 | { |
661 | if (btrfs_is_testing(fs_info: root->fs_info)) |
662 | return 0; |
663 | |
664 | /* Ensure we can see the FORCE_COW bit */ |
665 | smp_mb__before_atomic(); |
666 | |
667 | /* |
668 | * We do not need to cow a block if |
669 | * 1) this block is not created or changed in this transaction; |
670 | * 2) this block does not belong to TREE_RELOC tree; |
671 | * 3) the root is not forced COW. |
672 | * |
673 | * What is forced COW: |
674 | * when we create snapshot during committing the transaction, |
675 | * after we've finished copying src root, we must COW the shared |
676 | * block to ensure the metadata consistency. |
677 | */ |
678 | if (btrfs_header_generation(eb: buf) == trans->transid && |
679 | !btrfs_header_flag(eb: buf, BTRFS_HEADER_FLAG_WRITTEN) && |
680 | !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && |
681 | btrfs_header_flag(eb: buf, BTRFS_HEADER_FLAG_RELOC)) && |
682 | !test_bit(BTRFS_ROOT_FORCE_COW, &root->state)) |
683 | return 0; |
684 | return 1; |
685 | } |
686 | |
687 | /* |
688 | * COWs a single block, see btrfs_force_cow_block() for the real work. |
689 | * This version of it has extra checks so that a block isn't COWed more than |
690 | * once per transaction, as long as it hasn't been written yet |
691 | */ |
692 | int btrfs_cow_block(struct btrfs_trans_handle *trans, |
693 | struct btrfs_root *root, struct extent_buffer *buf, |
694 | struct extent_buffer *parent, int parent_slot, |
695 | struct extent_buffer **cow_ret, |
696 | enum btrfs_lock_nesting nest) |
697 | { |
698 | struct btrfs_fs_info *fs_info = root->fs_info; |
699 | u64 search_start; |
700 | int ret; |
701 | |
702 | if (unlikely(test_bit(BTRFS_ROOT_DELETING, &root->state))) { |
703 | btrfs_abort_transaction(trans, -EUCLEAN); |
704 | btrfs_crit(fs_info, |
705 | "attempt to COW block %llu on root %llu that is being deleted" , |
706 | buf->start, btrfs_root_id(root)); |
707 | return -EUCLEAN; |
708 | } |
709 | |
710 | /* |
711 | * COWing must happen through a running transaction, which always |
712 | * matches the current fs generation (it's a transaction with a state |
713 | * less than TRANS_STATE_UNBLOCKED). If it doesn't, then turn the fs |
714 | * into error state to prevent the commit of any transaction. |
715 | */ |
716 | if (unlikely(trans->transaction != fs_info->running_transaction || |
717 | trans->transid != fs_info->generation)) { |
718 | btrfs_abort_transaction(trans, -EUCLEAN); |
719 | btrfs_crit(fs_info, |
720 | "unexpected transaction when attempting to COW block %llu on root %llu, transaction %llu running transaction %llu fs generation %llu" , |
721 | buf->start, btrfs_root_id(root), trans->transid, |
722 | fs_info->running_transaction->transid, |
723 | fs_info->generation); |
724 | return -EUCLEAN; |
725 | } |
726 | |
727 | if (!should_cow_block(trans, root, buf)) { |
728 | *cow_ret = buf; |
729 | return 0; |
730 | } |
731 | |
732 | search_start = round_down(buf->start, SZ_1G); |
733 | |
734 | /* |
735 | * Before CoWing this block for later modification, check if it's |
736 | * the subtree root and do the delayed subtree trace if needed. |
737 | * |
738 | * Also We don't care about the error, as it's handled internally. |
739 | */ |
740 | btrfs_qgroup_trace_subtree_after_cow(trans, root, eb: buf); |
741 | ret = btrfs_force_cow_block(trans, root, buf, parent, parent_slot, |
742 | cow_ret, search_start, empty_size: 0, nest); |
743 | |
744 | trace_btrfs_cow_block(root, buf, cow: *cow_ret); |
745 | |
746 | return ret; |
747 | } |
748 | ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO); |
749 | |
750 | /* |
751 | * same as comp_keys only with two btrfs_key's |
752 | */ |
753 | int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) |
754 | { |
755 | if (k1->objectid > k2->objectid) |
756 | return 1; |
757 | if (k1->objectid < k2->objectid) |
758 | return -1; |
759 | if (k1->type > k2->type) |
760 | return 1; |
761 | if (k1->type < k2->type) |
762 | return -1; |
763 | if (k1->offset > k2->offset) |
764 | return 1; |
765 | if (k1->offset < k2->offset) |
766 | return -1; |
767 | return 0; |
768 | } |
769 | |
770 | /* |
771 | * Search for a key in the given extent_buffer. |
772 | * |
773 | * The lower boundary for the search is specified by the slot number @first_slot. |
774 | * Use a value of 0 to search over the whole extent buffer. Works for both |
775 | * leaves and nodes. |
776 | * |
777 | * The slot in the extent buffer is returned via @slot. If the key exists in the |
778 | * extent buffer, then @slot will point to the slot where the key is, otherwise |
779 | * it points to the slot where you would insert the key. |
780 | * |
781 | * Slot may point to the total number of items (i.e. one position beyond the last |
782 | * key) if the key is bigger than the last key in the extent buffer. |
783 | */ |
784 | int btrfs_bin_search(struct extent_buffer *eb, int first_slot, |
785 | const struct btrfs_key *key, int *slot) |
786 | { |
787 | unsigned long p; |
788 | int item_size; |
789 | /* |
790 | * Use unsigned types for the low and high slots, so that we get a more |
791 | * efficient division in the search loop below. |
792 | */ |
793 | u32 low = first_slot; |
794 | u32 high = btrfs_header_nritems(eb); |
795 | int ret; |
796 | const int key_size = sizeof(struct btrfs_disk_key); |
797 | |
798 | if (unlikely(low > high)) { |
799 | btrfs_err(eb->fs_info, |
800 | "%s: low (%u) > high (%u) eb %llu owner %llu level %d" , |
801 | __func__, low, high, eb->start, |
802 | btrfs_header_owner(eb), btrfs_header_level(eb)); |
803 | return -EINVAL; |
804 | } |
805 | |
806 | if (btrfs_header_level(eb) == 0) { |
807 | p = offsetof(struct btrfs_leaf, items); |
808 | item_size = sizeof(struct btrfs_item); |
809 | } else { |
810 | p = offsetof(struct btrfs_node, ptrs); |
811 | item_size = sizeof(struct btrfs_key_ptr); |
812 | } |
813 | |
814 | while (low < high) { |
815 | unsigned long oip; |
816 | unsigned long offset; |
817 | struct btrfs_disk_key *tmp; |
818 | struct btrfs_disk_key unaligned; |
819 | int mid; |
820 | |
821 | mid = (low + high) / 2; |
822 | offset = p + mid * item_size; |
823 | oip = offset_in_page(offset); |
824 | |
825 | if (oip + key_size <= PAGE_SIZE) { |
826 | const unsigned long idx = get_eb_page_index(offset); |
827 | char *kaddr = page_address(eb->pages[idx]); |
828 | |
829 | oip = get_eb_offset_in_page(eb, offset); |
830 | tmp = (struct btrfs_disk_key *)(kaddr + oip); |
831 | } else { |
832 | read_extent_buffer(eb, dst: &unaligned, start: offset, len: key_size); |
833 | tmp = &unaligned; |
834 | } |
835 | |
836 | ret = btrfs_comp_keys(disk_key: tmp, k2: key); |
837 | |
838 | if (ret < 0) |
839 | low = mid + 1; |
840 | else if (ret > 0) |
841 | high = mid; |
842 | else { |
843 | *slot = mid; |
844 | return 0; |
845 | } |
846 | } |
847 | *slot = low; |
848 | return 1; |
849 | } |
850 | |
851 | static void root_add_used_bytes(struct btrfs_root *root) |
852 | { |
853 | spin_lock(lock: &root->accounting_lock); |
854 | btrfs_set_root_used(s: &root->root_item, |
855 | val: btrfs_root_used(s: &root->root_item) + root->fs_info->nodesize); |
856 | spin_unlock(lock: &root->accounting_lock); |
857 | } |
858 | |
859 | static void root_sub_used_bytes(struct btrfs_root *root) |
860 | { |
861 | spin_lock(lock: &root->accounting_lock); |
862 | btrfs_set_root_used(s: &root->root_item, |
863 | val: btrfs_root_used(s: &root->root_item) - root->fs_info->nodesize); |
864 | spin_unlock(lock: &root->accounting_lock); |
865 | } |
866 | |
867 | /* given a node and slot number, this reads the blocks it points to. The |
868 | * extent buffer is returned with a reference taken (but unlocked). |
869 | */ |
870 | struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, |
871 | int slot) |
872 | { |
873 | int level = btrfs_header_level(eb: parent); |
874 | struct btrfs_tree_parent_check check = { 0 }; |
875 | struct extent_buffer *eb; |
876 | |
877 | if (slot < 0 || slot >= btrfs_header_nritems(eb: parent)) |
878 | return ERR_PTR(error: -ENOENT); |
879 | |
880 | ASSERT(level); |
881 | |
882 | check.level = level - 1; |
883 | check.transid = btrfs_node_ptr_generation(eb: parent, nr: slot); |
884 | check.owner_root = btrfs_header_owner(eb: parent); |
885 | check.has_first_key = true; |
886 | btrfs_node_key_to_cpu(eb: parent, cpu_key: &check.first_key, nr: slot); |
887 | |
888 | eb = read_tree_block(fs_info: parent->fs_info, bytenr: btrfs_node_blockptr(eb: parent, nr: slot), |
889 | check: &check); |
890 | if (IS_ERR(ptr: eb)) |
891 | return eb; |
892 | if (!extent_buffer_uptodate(eb)) { |
893 | free_extent_buffer(eb); |
894 | return ERR_PTR(error: -EIO); |
895 | } |
896 | |
897 | return eb; |
898 | } |
899 | |
900 | /* |
901 | * node level balancing, used to make sure nodes are in proper order for |
902 | * item deletion. We balance from the top down, so we have to make sure |
903 | * that a deletion won't leave an node completely empty later on. |
904 | */ |
905 | static noinline int balance_level(struct btrfs_trans_handle *trans, |
906 | struct btrfs_root *root, |
907 | struct btrfs_path *path, int level) |
908 | { |
909 | struct btrfs_fs_info *fs_info = root->fs_info; |
910 | struct extent_buffer *right = NULL; |
911 | struct extent_buffer *mid; |
912 | struct extent_buffer *left = NULL; |
913 | struct extent_buffer *parent = NULL; |
914 | int ret = 0; |
915 | int wret; |
916 | int pslot; |
917 | int orig_slot = path->slots[level]; |
918 | u64 orig_ptr; |
919 | |
920 | ASSERT(level > 0); |
921 | |
922 | mid = path->nodes[level]; |
923 | |
924 | WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK); |
925 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
926 | |
927 | orig_ptr = btrfs_node_blockptr(eb: mid, nr: orig_slot); |
928 | |
929 | if (level < BTRFS_MAX_LEVEL - 1) { |
930 | parent = path->nodes[level + 1]; |
931 | pslot = path->slots[level + 1]; |
932 | } |
933 | |
934 | /* |
935 | * deal with the case where there is only one pointer in the root |
936 | * by promoting the node below to a root |
937 | */ |
938 | if (!parent) { |
939 | struct extent_buffer *child; |
940 | |
941 | if (btrfs_header_nritems(eb: mid) != 1) |
942 | return 0; |
943 | |
944 | /* promote the child to a root */ |
945 | child = btrfs_read_node_slot(parent: mid, slot: 0); |
946 | if (IS_ERR(ptr: child)) { |
947 | ret = PTR_ERR(ptr: child); |
948 | goto out; |
949 | } |
950 | |
951 | btrfs_tree_lock(eb: child); |
952 | ret = btrfs_cow_block(trans, root, buf: child, parent: mid, parent_slot: 0, cow_ret: &child, |
953 | nest: BTRFS_NESTING_COW); |
954 | if (ret) { |
955 | btrfs_tree_unlock(eb: child); |
956 | free_extent_buffer(eb: child); |
957 | goto out; |
958 | } |
959 | |
960 | ret = btrfs_tree_mod_log_insert_root(old_root: root->node, new_root: child, log_removal: true); |
961 | if (ret < 0) { |
962 | btrfs_tree_unlock(eb: child); |
963 | free_extent_buffer(eb: child); |
964 | btrfs_abort_transaction(trans, ret); |
965 | goto out; |
966 | } |
967 | rcu_assign_pointer(root->node, child); |
968 | |
969 | add_root_to_dirty_list(root); |
970 | btrfs_tree_unlock(eb: child); |
971 | |
972 | path->locks[level] = 0; |
973 | path->nodes[level] = NULL; |
974 | btrfs_clear_buffer_dirty(trans, buf: mid); |
975 | btrfs_tree_unlock(eb: mid); |
976 | /* once for the path */ |
977 | free_extent_buffer(eb: mid); |
978 | |
979 | root_sub_used_bytes(root); |
980 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf: mid, parent: 0, last_ref: 1); |
981 | /* once for the root ptr */ |
982 | free_extent_buffer_stale(eb: mid); |
983 | return 0; |
984 | } |
985 | if (btrfs_header_nritems(eb: mid) > |
986 | BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) / 4) |
987 | return 0; |
988 | |
989 | if (pslot) { |
990 | left = btrfs_read_node_slot(parent, slot: pslot - 1); |
991 | if (IS_ERR(ptr: left)) { |
992 | ret = PTR_ERR(ptr: left); |
993 | left = NULL; |
994 | goto out; |
995 | } |
996 | |
997 | __btrfs_tree_lock(eb: left, nest: BTRFS_NESTING_LEFT); |
998 | wret = btrfs_cow_block(trans, root, buf: left, |
999 | parent, parent_slot: pslot - 1, cow_ret: &left, |
1000 | nest: BTRFS_NESTING_LEFT_COW); |
1001 | if (wret) { |
1002 | ret = wret; |
1003 | goto out; |
1004 | } |
1005 | } |
1006 | |
1007 | if (pslot + 1 < btrfs_header_nritems(eb: parent)) { |
1008 | right = btrfs_read_node_slot(parent, slot: pslot + 1); |
1009 | if (IS_ERR(ptr: right)) { |
1010 | ret = PTR_ERR(ptr: right); |
1011 | right = NULL; |
1012 | goto out; |
1013 | } |
1014 | |
1015 | __btrfs_tree_lock(eb: right, nest: BTRFS_NESTING_RIGHT); |
1016 | wret = btrfs_cow_block(trans, root, buf: right, |
1017 | parent, parent_slot: pslot + 1, cow_ret: &right, |
1018 | nest: BTRFS_NESTING_RIGHT_COW); |
1019 | if (wret) { |
1020 | ret = wret; |
1021 | goto out; |
1022 | } |
1023 | } |
1024 | |
1025 | /* first, try to make some room in the middle buffer */ |
1026 | if (left) { |
1027 | orig_slot += btrfs_header_nritems(eb: left); |
1028 | wret = push_node_left(trans, dst: left, src: mid, empty: 1); |
1029 | if (wret < 0) |
1030 | ret = wret; |
1031 | } |
1032 | |
1033 | /* |
1034 | * then try to empty the right most buffer into the middle |
1035 | */ |
1036 | if (right) { |
1037 | wret = push_node_left(trans, dst: mid, src: right, empty: 1); |
1038 | if (wret < 0 && wret != -ENOSPC) |
1039 | ret = wret; |
1040 | if (btrfs_header_nritems(eb: right) == 0) { |
1041 | btrfs_clear_buffer_dirty(trans, buf: right); |
1042 | btrfs_tree_unlock(eb: right); |
1043 | ret = btrfs_del_ptr(trans, root, path, level: level + 1, slot: pslot + 1); |
1044 | if (ret < 0) { |
1045 | free_extent_buffer_stale(eb: right); |
1046 | right = NULL; |
1047 | goto out; |
1048 | } |
1049 | root_sub_used_bytes(root); |
1050 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf: right, |
1051 | parent: 0, last_ref: 1); |
1052 | free_extent_buffer_stale(eb: right); |
1053 | right = NULL; |
1054 | } else { |
1055 | struct btrfs_disk_key right_key; |
1056 | btrfs_node_key(eb: right, disk_key: &right_key, nr: 0); |
1057 | ret = btrfs_tree_mod_log_insert_key(eb: parent, slot: pslot + 1, |
1058 | op: BTRFS_MOD_LOG_KEY_REPLACE); |
1059 | if (ret < 0) { |
1060 | btrfs_abort_transaction(trans, ret); |
1061 | goto out; |
1062 | } |
1063 | btrfs_set_node_key(eb: parent, disk_key: &right_key, nr: pslot + 1); |
1064 | btrfs_mark_buffer_dirty(trans, buf: parent); |
1065 | } |
1066 | } |
1067 | if (btrfs_header_nritems(eb: mid) == 1) { |
1068 | /* |
1069 | * we're not allowed to leave a node with one item in the |
1070 | * tree during a delete. A deletion from lower in the tree |
1071 | * could try to delete the only pointer in this node. |
1072 | * So, pull some keys from the left. |
1073 | * There has to be a left pointer at this point because |
1074 | * otherwise we would have pulled some pointers from the |
1075 | * right |
1076 | */ |
1077 | if (unlikely(!left)) { |
1078 | btrfs_crit(fs_info, |
1079 | "missing left child when middle child only has 1 item, parent bytenr %llu level %d mid bytenr %llu root %llu" , |
1080 | parent->start, btrfs_header_level(parent), |
1081 | mid->start, btrfs_root_id(root)); |
1082 | ret = -EUCLEAN; |
1083 | btrfs_abort_transaction(trans, ret); |
1084 | goto out; |
1085 | } |
1086 | wret = balance_node_right(trans, dst_buf: mid, src_buf: left); |
1087 | if (wret < 0) { |
1088 | ret = wret; |
1089 | goto out; |
1090 | } |
1091 | if (wret == 1) { |
1092 | wret = push_node_left(trans, dst: left, src: mid, empty: 1); |
1093 | if (wret < 0) |
1094 | ret = wret; |
1095 | } |
1096 | BUG_ON(wret == 1); |
1097 | } |
1098 | if (btrfs_header_nritems(eb: mid) == 0) { |
1099 | btrfs_clear_buffer_dirty(trans, buf: mid); |
1100 | btrfs_tree_unlock(eb: mid); |
1101 | ret = btrfs_del_ptr(trans, root, path, level: level + 1, slot: pslot); |
1102 | if (ret < 0) { |
1103 | free_extent_buffer_stale(eb: mid); |
1104 | mid = NULL; |
1105 | goto out; |
1106 | } |
1107 | root_sub_used_bytes(root); |
1108 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf: mid, parent: 0, last_ref: 1); |
1109 | free_extent_buffer_stale(eb: mid); |
1110 | mid = NULL; |
1111 | } else { |
1112 | /* update the parent key to reflect our changes */ |
1113 | struct btrfs_disk_key mid_key; |
1114 | btrfs_node_key(eb: mid, disk_key: &mid_key, nr: 0); |
1115 | ret = btrfs_tree_mod_log_insert_key(eb: parent, slot: pslot, |
1116 | op: BTRFS_MOD_LOG_KEY_REPLACE); |
1117 | if (ret < 0) { |
1118 | btrfs_abort_transaction(trans, ret); |
1119 | goto out; |
1120 | } |
1121 | btrfs_set_node_key(eb: parent, disk_key: &mid_key, nr: pslot); |
1122 | btrfs_mark_buffer_dirty(trans, buf: parent); |
1123 | } |
1124 | |
1125 | /* update the path */ |
1126 | if (left) { |
1127 | if (btrfs_header_nritems(eb: left) > orig_slot) { |
1128 | atomic_inc(v: &left->refs); |
1129 | /* left was locked after cow */ |
1130 | path->nodes[level] = left; |
1131 | path->slots[level + 1] -= 1; |
1132 | path->slots[level] = orig_slot; |
1133 | if (mid) { |
1134 | btrfs_tree_unlock(eb: mid); |
1135 | free_extent_buffer(eb: mid); |
1136 | } |
1137 | } else { |
1138 | orig_slot -= btrfs_header_nritems(eb: left); |
1139 | path->slots[level] = orig_slot; |
1140 | } |
1141 | } |
1142 | /* double check we haven't messed things up */ |
1143 | if (orig_ptr != |
1144 | btrfs_node_blockptr(eb: path->nodes[level], nr: path->slots[level])) |
1145 | BUG(); |
1146 | out: |
1147 | if (right) { |
1148 | btrfs_tree_unlock(eb: right); |
1149 | free_extent_buffer(eb: right); |
1150 | } |
1151 | if (left) { |
1152 | if (path->nodes[level] != left) |
1153 | btrfs_tree_unlock(eb: left); |
1154 | free_extent_buffer(eb: left); |
1155 | } |
1156 | return ret; |
1157 | } |
1158 | |
1159 | /* Node balancing for insertion. Here we only split or push nodes around |
1160 | * when they are completely full. This is also done top down, so we |
1161 | * have to be pessimistic. |
1162 | */ |
1163 | static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, |
1164 | struct btrfs_root *root, |
1165 | struct btrfs_path *path, int level) |
1166 | { |
1167 | struct btrfs_fs_info *fs_info = root->fs_info; |
1168 | struct extent_buffer *right = NULL; |
1169 | struct extent_buffer *mid; |
1170 | struct extent_buffer *left = NULL; |
1171 | struct extent_buffer *parent = NULL; |
1172 | int ret = 0; |
1173 | int wret; |
1174 | int pslot; |
1175 | int orig_slot = path->slots[level]; |
1176 | |
1177 | if (level == 0) |
1178 | return 1; |
1179 | |
1180 | mid = path->nodes[level]; |
1181 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
1182 | |
1183 | if (level < BTRFS_MAX_LEVEL - 1) { |
1184 | parent = path->nodes[level + 1]; |
1185 | pslot = path->slots[level + 1]; |
1186 | } |
1187 | |
1188 | if (!parent) |
1189 | return 1; |
1190 | |
1191 | /* first, try to make some room in the middle buffer */ |
1192 | if (pslot) { |
1193 | u32 left_nr; |
1194 | |
1195 | left = btrfs_read_node_slot(parent, slot: pslot - 1); |
1196 | if (IS_ERR(ptr: left)) |
1197 | return PTR_ERR(ptr: left); |
1198 | |
1199 | __btrfs_tree_lock(eb: left, nest: BTRFS_NESTING_LEFT); |
1200 | |
1201 | left_nr = btrfs_header_nritems(eb: left); |
1202 | if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) - 1) { |
1203 | wret = 1; |
1204 | } else { |
1205 | ret = btrfs_cow_block(trans, root, buf: left, parent, |
1206 | parent_slot: pslot - 1, cow_ret: &left, |
1207 | nest: BTRFS_NESTING_LEFT_COW); |
1208 | if (ret) |
1209 | wret = 1; |
1210 | else { |
1211 | wret = push_node_left(trans, dst: left, src: mid, empty: 0); |
1212 | } |
1213 | } |
1214 | if (wret < 0) |
1215 | ret = wret; |
1216 | if (wret == 0) { |
1217 | struct btrfs_disk_key disk_key; |
1218 | orig_slot += left_nr; |
1219 | btrfs_node_key(eb: mid, disk_key: &disk_key, nr: 0); |
1220 | ret = btrfs_tree_mod_log_insert_key(eb: parent, slot: pslot, |
1221 | op: BTRFS_MOD_LOG_KEY_REPLACE); |
1222 | if (ret < 0) { |
1223 | btrfs_tree_unlock(eb: left); |
1224 | free_extent_buffer(eb: left); |
1225 | btrfs_abort_transaction(trans, ret); |
1226 | return ret; |
1227 | } |
1228 | btrfs_set_node_key(eb: parent, disk_key: &disk_key, nr: pslot); |
1229 | btrfs_mark_buffer_dirty(trans, buf: parent); |
1230 | if (btrfs_header_nritems(eb: left) > orig_slot) { |
1231 | path->nodes[level] = left; |
1232 | path->slots[level + 1] -= 1; |
1233 | path->slots[level] = orig_slot; |
1234 | btrfs_tree_unlock(eb: mid); |
1235 | free_extent_buffer(eb: mid); |
1236 | } else { |
1237 | orig_slot -= |
1238 | btrfs_header_nritems(eb: left); |
1239 | path->slots[level] = orig_slot; |
1240 | btrfs_tree_unlock(eb: left); |
1241 | free_extent_buffer(eb: left); |
1242 | } |
1243 | return 0; |
1244 | } |
1245 | btrfs_tree_unlock(eb: left); |
1246 | free_extent_buffer(eb: left); |
1247 | } |
1248 | |
1249 | /* |
1250 | * then try to empty the right most buffer into the middle |
1251 | */ |
1252 | if (pslot + 1 < btrfs_header_nritems(eb: parent)) { |
1253 | u32 right_nr; |
1254 | |
1255 | right = btrfs_read_node_slot(parent, slot: pslot + 1); |
1256 | if (IS_ERR(ptr: right)) |
1257 | return PTR_ERR(ptr: right); |
1258 | |
1259 | __btrfs_tree_lock(eb: right, nest: BTRFS_NESTING_RIGHT); |
1260 | |
1261 | right_nr = btrfs_header_nritems(eb: right); |
1262 | if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) - 1) { |
1263 | wret = 1; |
1264 | } else { |
1265 | ret = btrfs_cow_block(trans, root, buf: right, |
1266 | parent, parent_slot: pslot + 1, |
1267 | cow_ret: &right, nest: BTRFS_NESTING_RIGHT_COW); |
1268 | if (ret) |
1269 | wret = 1; |
1270 | else { |
1271 | wret = balance_node_right(trans, dst_buf: right, src_buf: mid); |
1272 | } |
1273 | } |
1274 | if (wret < 0) |
1275 | ret = wret; |
1276 | if (wret == 0) { |
1277 | struct btrfs_disk_key disk_key; |
1278 | |
1279 | btrfs_node_key(eb: right, disk_key: &disk_key, nr: 0); |
1280 | ret = btrfs_tree_mod_log_insert_key(eb: parent, slot: pslot + 1, |
1281 | op: BTRFS_MOD_LOG_KEY_REPLACE); |
1282 | if (ret < 0) { |
1283 | btrfs_tree_unlock(eb: right); |
1284 | free_extent_buffer(eb: right); |
1285 | btrfs_abort_transaction(trans, ret); |
1286 | return ret; |
1287 | } |
1288 | btrfs_set_node_key(eb: parent, disk_key: &disk_key, nr: pslot + 1); |
1289 | btrfs_mark_buffer_dirty(trans, buf: parent); |
1290 | |
1291 | if (btrfs_header_nritems(eb: mid) <= orig_slot) { |
1292 | path->nodes[level] = right; |
1293 | path->slots[level + 1] += 1; |
1294 | path->slots[level] = orig_slot - |
1295 | btrfs_header_nritems(eb: mid); |
1296 | btrfs_tree_unlock(eb: mid); |
1297 | free_extent_buffer(eb: mid); |
1298 | } else { |
1299 | btrfs_tree_unlock(eb: right); |
1300 | free_extent_buffer(eb: right); |
1301 | } |
1302 | return 0; |
1303 | } |
1304 | btrfs_tree_unlock(eb: right); |
1305 | free_extent_buffer(eb: right); |
1306 | } |
1307 | return 1; |
1308 | } |
1309 | |
1310 | /* |
1311 | * readahead one full node of leaves, finding things that are close |
1312 | * to the block in 'slot', and triggering ra on them. |
1313 | */ |
1314 | static void reada_for_search(struct btrfs_fs_info *fs_info, |
1315 | struct btrfs_path *path, |
1316 | int level, int slot, u64 objectid) |
1317 | { |
1318 | struct extent_buffer *node; |
1319 | struct btrfs_disk_key disk_key; |
1320 | u32 nritems; |
1321 | u64 search; |
1322 | u64 target; |
1323 | u64 nread = 0; |
1324 | u64 nread_max; |
1325 | u32 nr; |
1326 | u32 blocksize; |
1327 | u32 nscan = 0; |
1328 | |
1329 | if (level != 1 && path->reada != READA_FORWARD_ALWAYS) |
1330 | return; |
1331 | |
1332 | if (!path->nodes[level]) |
1333 | return; |
1334 | |
1335 | node = path->nodes[level]; |
1336 | |
1337 | /* |
1338 | * Since the time between visiting leaves is much shorter than the time |
1339 | * between visiting nodes, limit read ahead of nodes to 1, to avoid too |
1340 | * much IO at once (possibly random). |
1341 | */ |
1342 | if (path->reada == READA_FORWARD_ALWAYS) { |
1343 | if (level > 1) |
1344 | nread_max = node->fs_info->nodesize; |
1345 | else |
1346 | nread_max = SZ_128K; |
1347 | } else { |
1348 | nread_max = SZ_64K; |
1349 | } |
1350 | |
1351 | search = btrfs_node_blockptr(eb: node, nr: slot); |
1352 | blocksize = fs_info->nodesize; |
1353 | if (path->reada != READA_FORWARD_ALWAYS) { |
1354 | struct extent_buffer *eb; |
1355 | |
1356 | eb = find_extent_buffer(fs_info, start: search); |
1357 | if (eb) { |
1358 | free_extent_buffer(eb); |
1359 | return; |
1360 | } |
1361 | } |
1362 | |
1363 | target = search; |
1364 | |
1365 | nritems = btrfs_header_nritems(eb: node); |
1366 | nr = slot; |
1367 | |
1368 | while (1) { |
1369 | if (path->reada == READA_BACK) { |
1370 | if (nr == 0) |
1371 | break; |
1372 | nr--; |
1373 | } else if (path->reada == READA_FORWARD || |
1374 | path->reada == READA_FORWARD_ALWAYS) { |
1375 | nr++; |
1376 | if (nr >= nritems) |
1377 | break; |
1378 | } |
1379 | if (path->reada == READA_BACK && objectid) { |
1380 | btrfs_node_key(eb: node, disk_key: &disk_key, nr); |
1381 | if (btrfs_disk_key_objectid(s: &disk_key) != objectid) |
1382 | break; |
1383 | } |
1384 | search = btrfs_node_blockptr(eb: node, nr); |
1385 | if (path->reada == READA_FORWARD_ALWAYS || |
1386 | (search <= target && target - search <= 65536) || |
1387 | (search > target && search - target <= 65536)) { |
1388 | btrfs_readahead_node_child(node, slot: nr); |
1389 | nread += blocksize; |
1390 | } |
1391 | nscan++; |
1392 | if (nread > nread_max || nscan > 32) |
1393 | break; |
1394 | } |
1395 | } |
1396 | |
1397 | static noinline void reada_for_balance(struct btrfs_path *path, int level) |
1398 | { |
1399 | struct extent_buffer *parent; |
1400 | int slot; |
1401 | int nritems; |
1402 | |
1403 | parent = path->nodes[level + 1]; |
1404 | if (!parent) |
1405 | return; |
1406 | |
1407 | nritems = btrfs_header_nritems(eb: parent); |
1408 | slot = path->slots[level + 1]; |
1409 | |
1410 | if (slot > 0) |
1411 | btrfs_readahead_node_child(node: parent, slot: slot - 1); |
1412 | if (slot + 1 < nritems) |
1413 | btrfs_readahead_node_child(node: parent, slot: slot + 1); |
1414 | } |
1415 | |
1416 | |
1417 | /* |
1418 | * when we walk down the tree, it is usually safe to unlock the higher layers |
1419 | * in the tree. The exceptions are when our path goes through slot 0, because |
1420 | * operations on the tree might require changing key pointers higher up in the |
1421 | * tree. |
1422 | * |
1423 | * callers might also have set path->keep_locks, which tells this code to keep |
1424 | * the lock if the path points to the last slot in the block. This is part of |
1425 | * walking through the tree, and selecting the next slot in the higher block. |
1426 | * |
1427 | * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so |
1428 | * if lowest_unlock is 1, level 0 won't be unlocked |
1429 | */ |
1430 | static noinline void unlock_up(struct btrfs_path *path, int level, |
1431 | int lowest_unlock, int min_write_lock_level, |
1432 | int *write_lock_level) |
1433 | { |
1434 | int i; |
1435 | int skip_level = level; |
1436 | bool check_skip = true; |
1437 | |
1438 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
1439 | if (!path->nodes[i]) |
1440 | break; |
1441 | if (!path->locks[i]) |
1442 | break; |
1443 | |
1444 | if (check_skip) { |
1445 | if (path->slots[i] == 0) { |
1446 | skip_level = i + 1; |
1447 | continue; |
1448 | } |
1449 | |
1450 | if (path->keep_locks) { |
1451 | u32 nritems; |
1452 | |
1453 | nritems = btrfs_header_nritems(eb: path->nodes[i]); |
1454 | if (nritems < 1 || path->slots[i] >= nritems - 1) { |
1455 | skip_level = i + 1; |
1456 | continue; |
1457 | } |
1458 | } |
1459 | } |
1460 | |
1461 | if (i >= lowest_unlock && i > skip_level) { |
1462 | check_skip = false; |
1463 | btrfs_tree_unlock_rw(eb: path->nodes[i], rw: path->locks[i]); |
1464 | path->locks[i] = 0; |
1465 | if (write_lock_level && |
1466 | i > min_write_lock_level && |
1467 | i <= *write_lock_level) { |
1468 | *write_lock_level = i - 1; |
1469 | } |
1470 | } |
1471 | } |
1472 | } |
1473 | |
1474 | /* |
1475 | * Helper function for btrfs_search_slot() and other functions that do a search |
1476 | * on a btree. The goal is to find a tree block in the cache (the radix tree at |
1477 | * fs_info->buffer_radix), but if we can't find it, or it's not up to date, read |
1478 | * its pages from disk. |
1479 | * |
1480 | * Returns -EAGAIN, with the path unlocked, if the caller needs to repeat the |
1481 | * whole btree search, starting again from the current root node. |
1482 | */ |
1483 | static int |
1484 | read_block_for_search(struct btrfs_root *root, struct btrfs_path *p, |
1485 | struct extent_buffer **eb_ret, int level, int slot, |
1486 | const struct btrfs_key *key) |
1487 | { |
1488 | struct btrfs_fs_info *fs_info = root->fs_info; |
1489 | struct btrfs_tree_parent_check check = { 0 }; |
1490 | u64 blocknr; |
1491 | u64 gen; |
1492 | struct extent_buffer *tmp; |
1493 | int ret; |
1494 | int parent_level; |
1495 | bool unlock_up; |
1496 | |
1497 | unlock_up = ((level + 1 < BTRFS_MAX_LEVEL) && p->locks[level + 1]); |
1498 | blocknr = btrfs_node_blockptr(eb: *eb_ret, nr: slot); |
1499 | gen = btrfs_node_ptr_generation(eb: *eb_ret, nr: slot); |
1500 | parent_level = btrfs_header_level(eb: *eb_ret); |
1501 | btrfs_node_key_to_cpu(eb: *eb_ret, cpu_key: &check.first_key, nr: slot); |
1502 | check.has_first_key = true; |
1503 | check.level = parent_level - 1; |
1504 | check.transid = gen; |
1505 | check.owner_root = root->root_key.objectid; |
1506 | |
1507 | /* |
1508 | * If we need to read an extent buffer from disk and we are holding locks |
1509 | * on upper level nodes, we unlock all the upper nodes before reading the |
1510 | * extent buffer, and then return -EAGAIN to the caller as it needs to |
1511 | * restart the search. We don't release the lock on the current level |
1512 | * because we need to walk this node to figure out which blocks to read. |
1513 | */ |
1514 | tmp = find_extent_buffer(fs_info, start: blocknr); |
1515 | if (tmp) { |
1516 | if (p->reada == READA_FORWARD_ALWAYS) |
1517 | reada_for_search(fs_info, path: p, level, slot, objectid: key->objectid); |
1518 | |
1519 | /* first we do an atomic uptodate check */ |
1520 | if (btrfs_buffer_uptodate(buf: tmp, parent_transid: gen, atomic: 1) > 0) { |
1521 | /* |
1522 | * Do extra check for first_key, eb can be stale due to |
1523 | * being cached, read from scrub, or have multiple |
1524 | * parents (shared tree blocks). |
1525 | */ |
1526 | if (btrfs_verify_level_key(eb: tmp, |
1527 | level: parent_level - 1, first_key: &check.first_key, parent_transid: gen)) { |
1528 | free_extent_buffer(eb: tmp); |
1529 | return -EUCLEAN; |
1530 | } |
1531 | *eb_ret = tmp; |
1532 | return 0; |
1533 | } |
1534 | |
1535 | if (p->nowait) { |
1536 | free_extent_buffer(eb: tmp); |
1537 | return -EAGAIN; |
1538 | } |
1539 | |
1540 | if (unlock_up) |
1541 | btrfs_unlock_up_safe(path: p, level: level + 1); |
1542 | |
1543 | /* now we're allowed to do a blocking uptodate check */ |
1544 | ret = btrfs_read_extent_buffer(buf: tmp, check: &check); |
1545 | if (ret) { |
1546 | free_extent_buffer(eb: tmp); |
1547 | btrfs_release_path(p); |
1548 | return -EIO; |
1549 | } |
1550 | if (btrfs_check_eb_owner(eb: tmp, root_owner: root->root_key.objectid)) { |
1551 | free_extent_buffer(eb: tmp); |
1552 | btrfs_release_path(p); |
1553 | return -EUCLEAN; |
1554 | } |
1555 | |
1556 | if (unlock_up) |
1557 | ret = -EAGAIN; |
1558 | |
1559 | goto out; |
1560 | } else if (p->nowait) { |
1561 | return -EAGAIN; |
1562 | } |
1563 | |
1564 | if (unlock_up) { |
1565 | btrfs_unlock_up_safe(path: p, level: level + 1); |
1566 | ret = -EAGAIN; |
1567 | } else { |
1568 | ret = 0; |
1569 | } |
1570 | |
1571 | if (p->reada != READA_NONE) |
1572 | reada_for_search(fs_info, path: p, level, slot, objectid: key->objectid); |
1573 | |
1574 | tmp = read_tree_block(fs_info, bytenr: blocknr, check: &check); |
1575 | if (IS_ERR(ptr: tmp)) { |
1576 | btrfs_release_path(p); |
1577 | return PTR_ERR(ptr: tmp); |
1578 | } |
1579 | /* |
1580 | * If the read above didn't mark this buffer up to date, |
1581 | * it will never end up being up to date. Set ret to EIO now |
1582 | * and give up so that our caller doesn't loop forever |
1583 | * on our EAGAINs. |
1584 | */ |
1585 | if (!extent_buffer_uptodate(eb: tmp)) |
1586 | ret = -EIO; |
1587 | |
1588 | out: |
1589 | if (ret == 0) { |
1590 | *eb_ret = tmp; |
1591 | } else { |
1592 | free_extent_buffer(eb: tmp); |
1593 | btrfs_release_path(p); |
1594 | } |
1595 | |
1596 | return ret; |
1597 | } |
1598 | |
1599 | /* |
1600 | * helper function for btrfs_search_slot. This does all of the checks |
1601 | * for node-level blocks and does any balancing required based on |
1602 | * the ins_len. |
1603 | * |
1604 | * If no extra work was required, zero is returned. If we had to |
1605 | * drop the path, -EAGAIN is returned and btrfs_search_slot must |
1606 | * start over |
1607 | */ |
1608 | static int |
1609 | setup_nodes_for_search(struct btrfs_trans_handle *trans, |
1610 | struct btrfs_root *root, struct btrfs_path *p, |
1611 | struct extent_buffer *b, int level, int ins_len, |
1612 | int *write_lock_level) |
1613 | { |
1614 | struct btrfs_fs_info *fs_info = root->fs_info; |
1615 | int ret = 0; |
1616 | |
1617 | if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(eb: b) >= |
1618 | BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) - 3) { |
1619 | |
1620 | if (*write_lock_level < level + 1) { |
1621 | *write_lock_level = level + 1; |
1622 | btrfs_release_path(p); |
1623 | return -EAGAIN; |
1624 | } |
1625 | |
1626 | reada_for_balance(path: p, level); |
1627 | ret = split_node(trans, root, path: p, level); |
1628 | |
1629 | b = p->nodes[level]; |
1630 | } else if (ins_len < 0 && btrfs_header_nritems(eb: b) < |
1631 | BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) / 2) { |
1632 | |
1633 | if (*write_lock_level < level + 1) { |
1634 | *write_lock_level = level + 1; |
1635 | btrfs_release_path(p); |
1636 | return -EAGAIN; |
1637 | } |
1638 | |
1639 | reada_for_balance(path: p, level); |
1640 | ret = balance_level(trans, root, path: p, level); |
1641 | if (ret) |
1642 | return ret; |
1643 | |
1644 | b = p->nodes[level]; |
1645 | if (!b) { |
1646 | btrfs_release_path(p); |
1647 | return -EAGAIN; |
1648 | } |
1649 | BUG_ON(btrfs_header_nritems(b) == 1); |
1650 | } |
1651 | return ret; |
1652 | } |
1653 | |
1654 | int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path, |
1655 | u64 iobjectid, u64 ioff, u8 key_type, |
1656 | struct btrfs_key *found_key) |
1657 | { |
1658 | int ret; |
1659 | struct btrfs_key key; |
1660 | struct extent_buffer *eb; |
1661 | |
1662 | ASSERT(path); |
1663 | ASSERT(found_key); |
1664 | |
1665 | key.type = key_type; |
1666 | key.objectid = iobjectid; |
1667 | key.offset = ioff; |
1668 | |
1669 | ret = btrfs_search_slot(NULL, root: fs_root, key: &key, p: path, ins_len: 0, cow: 0); |
1670 | if (ret < 0) |
1671 | return ret; |
1672 | |
1673 | eb = path->nodes[0]; |
1674 | if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { |
1675 | ret = btrfs_next_leaf(root: fs_root, path); |
1676 | if (ret) |
1677 | return ret; |
1678 | eb = path->nodes[0]; |
1679 | } |
1680 | |
1681 | btrfs_item_key_to_cpu(eb, cpu_key: found_key, nr: path->slots[0]); |
1682 | if (found_key->type != key.type || |
1683 | found_key->objectid != key.objectid) |
1684 | return 1; |
1685 | |
1686 | return 0; |
1687 | } |
1688 | |
1689 | static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, |
1690 | struct btrfs_path *p, |
1691 | int write_lock_level) |
1692 | { |
1693 | struct extent_buffer *b; |
1694 | int root_lock = 0; |
1695 | int level = 0; |
1696 | |
1697 | if (p->search_commit_root) { |
1698 | b = root->commit_root; |
1699 | atomic_inc(v: &b->refs); |
1700 | level = btrfs_header_level(eb: b); |
1701 | /* |
1702 | * Ensure that all callers have set skip_locking when |
1703 | * p->search_commit_root = 1. |
1704 | */ |
1705 | ASSERT(p->skip_locking == 1); |
1706 | |
1707 | goto out; |
1708 | } |
1709 | |
1710 | if (p->skip_locking) { |
1711 | b = btrfs_root_node(root); |
1712 | level = btrfs_header_level(eb: b); |
1713 | goto out; |
1714 | } |
1715 | |
1716 | /* We try very hard to do read locks on the root */ |
1717 | root_lock = BTRFS_READ_LOCK; |
1718 | |
1719 | /* |
1720 | * If the level is set to maximum, we can skip trying to get the read |
1721 | * lock. |
1722 | */ |
1723 | if (write_lock_level < BTRFS_MAX_LEVEL) { |
1724 | /* |
1725 | * We don't know the level of the root node until we actually |
1726 | * have it read locked |
1727 | */ |
1728 | if (p->nowait) { |
1729 | b = btrfs_try_read_lock_root_node(root); |
1730 | if (IS_ERR(ptr: b)) |
1731 | return b; |
1732 | } else { |
1733 | b = btrfs_read_lock_root_node(root); |
1734 | } |
1735 | level = btrfs_header_level(eb: b); |
1736 | if (level > write_lock_level) |
1737 | goto out; |
1738 | |
1739 | /* Whoops, must trade for write lock */ |
1740 | btrfs_tree_read_unlock(eb: b); |
1741 | free_extent_buffer(eb: b); |
1742 | } |
1743 | |
1744 | b = btrfs_lock_root_node(root); |
1745 | root_lock = BTRFS_WRITE_LOCK; |
1746 | |
1747 | /* The level might have changed, check again */ |
1748 | level = btrfs_header_level(eb: b); |
1749 | |
1750 | out: |
1751 | /* |
1752 | * The root may have failed to write out at some point, and thus is no |
1753 | * longer valid, return an error in this case. |
1754 | */ |
1755 | if (!extent_buffer_uptodate(eb: b)) { |
1756 | if (root_lock) |
1757 | btrfs_tree_unlock_rw(eb: b, rw: root_lock); |
1758 | free_extent_buffer(eb: b); |
1759 | return ERR_PTR(error: -EIO); |
1760 | } |
1761 | |
1762 | p->nodes[level] = b; |
1763 | if (!p->skip_locking) |
1764 | p->locks[level] = root_lock; |
1765 | /* |
1766 | * Callers are responsible for dropping b's references. |
1767 | */ |
1768 | return b; |
1769 | } |
1770 | |
1771 | /* |
1772 | * Replace the extent buffer at the lowest level of the path with a cloned |
1773 | * version. The purpose is to be able to use it safely, after releasing the |
1774 | * commit root semaphore, even if relocation is happening in parallel, the |
1775 | * transaction used for relocation is committed and the extent buffer is |
1776 | * reallocated in the next transaction. |
1777 | * |
1778 | * This is used in a context where the caller does not prevent transaction |
1779 | * commits from happening, either by holding a transaction handle or holding |
1780 | * some lock, while it's doing searches through a commit root. |
1781 | * At the moment it's only used for send operations. |
1782 | */ |
1783 | static int finish_need_commit_sem_search(struct btrfs_path *path) |
1784 | { |
1785 | const int i = path->lowest_level; |
1786 | const int slot = path->slots[i]; |
1787 | struct extent_buffer *lowest = path->nodes[i]; |
1788 | struct extent_buffer *clone; |
1789 | |
1790 | ASSERT(path->need_commit_sem); |
1791 | |
1792 | if (!lowest) |
1793 | return 0; |
1794 | |
1795 | lockdep_assert_held_read(&lowest->fs_info->commit_root_sem); |
1796 | |
1797 | clone = btrfs_clone_extent_buffer(src: lowest); |
1798 | if (!clone) |
1799 | return -ENOMEM; |
1800 | |
1801 | btrfs_release_path(p: path); |
1802 | path->nodes[i] = clone; |
1803 | path->slots[i] = slot; |
1804 | |
1805 | return 0; |
1806 | } |
1807 | |
1808 | static inline int search_for_key_slot(struct extent_buffer *eb, |
1809 | int search_low_slot, |
1810 | const struct btrfs_key *key, |
1811 | int prev_cmp, |
1812 | int *slot) |
1813 | { |
1814 | /* |
1815 | * If a previous call to btrfs_bin_search() on a parent node returned an |
1816 | * exact match (prev_cmp == 0), we can safely assume the target key will |
1817 | * always be at slot 0 on lower levels, since each key pointer |
1818 | * (struct btrfs_key_ptr) refers to the lowest key accessible from the |
1819 | * subtree it points to. Thus we can skip searching lower levels. |
1820 | */ |
1821 | if (prev_cmp == 0) { |
1822 | *slot = 0; |
1823 | return 0; |
1824 | } |
1825 | |
1826 | return btrfs_bin_search(eb, first_slot: search_low_slot, key, slot); |
1827 | } |
1828 | |
1829 | static int search_leaf(struct btrfs_trans_handle *trans, |
1830 | struct btrfs_root *root, |
1831 | const struct btrfs_key *key, |
1832 | struct btrfs_path *path, |
1833 | int ins_len, |
1834 | int prev_cmp) |
1835 | { |
1836 | struct extent_buffer *leaf = path->nodes[0]; |
1837 | int leaf_free_space = -1; |
1838 | int search_low_slot = 0; |
1839 | int ret; |
1840 | bool do_bin_search = true; |
1841 | |
1842 | /* |
1843 | * If we are doing an insertion, the leaf has enough free space and the |
1844 | * destination slot for the key is not slot 0, then we can unlock our |
1845 | * write lock on the parent, and any other upper nodes, before doing the |
1846 | * binary search on the leaf (with search_for_key_slot()), allowing other |
1847 | * tasks to lock the parent and any other upper nodes. |
1848 | */ |
1849 | if (ins_len > 0) { |
1850 | /* |
1851 | * Cache the leaf free space, since we will need it later and it |
1852 | * will not change until then. |
1853 | */ |
1854 | leaf_free_space = btrfs_leaf_free_space(leaf); |
1855 | |
1856 | /* |
1857 | * !path->locks[1] means we have a single node tree, the leaf is |
1858 | * the root of the tree. |
1859 | */ |
1860 | if (path->locks[1] && leaf_free_space >= ins_len) { |
1861 | struct btrfs_disk_key first_key; |
1862 | |
1863 | ASSERT(btrfs_header_nritems(leaf) > 0); |
1864 | btrfs_item_key(eb: leaf, disk_key: &first_key, nr: 0); |
1865 | |
1866 | /* |
1867 | * Doing the extra comparison with the first key is cheap, |
1868 | * taking into account that the first key is very likely |
1869 | * already in a cache line because it immediately follows |
1870 | * the extent buffer's header and we have recently accessed |
1871 | * the header's level field. |
1872 | */ |
1873 | ret = btrfs_comp_keys(disk_key: &first_key, k2: key); |
1874 | if (ret < 0) { |
1875 | /* |
1876 | * The first key is smaller than the key we want |
1877 | * to insert, so we are safe to unlock all upper |
1878 | * nodes and we have to do the binary search. |
1879 | * |
1880 | * We do use btrfs_unlock_up_safe() and not |
1881 | * unlock_up() because the later does not unlock |
1882 | * nodes with a slot of 0 - we can safely unlock |
1883 | * any node even if its slot is 0 since in this |
1884 | * case the key does not end up at slot 0 of the |
1885 | * leaf and there's no need to split the leaf. |
1886 | */ |
1887 | btrfs_unlock_up_safe(path, level: 1); |
1888 | search_low_slot = 1; |
1889 | } else { |
1890 | /* |
1891 | * The first key is >= then the key we want to |
1892 | * insert, so we can skip the binary search as |
1893 | * the target key will be at slot 0. |
1894 | * |
1895 | * We can not unlock upper nodes when the key is |
1896 | * less than the first key, because we will need |
1897 | * to update the key at slot 0 of the parent node |
1898 | * and possibly of other upper nodes too. |
1899 | * If the key matches the first key, then we can |
1900 | * unlock all the upper nodes, using |
1901 | * btrfs_unlock_up_safe() instead of unlock_up() |
1902 | * as stated above. |
1903 | */ |
1904 | if (ret == 0) |
1905 | btrfs_unlock_up_safe(path, level: 1); |
1906 | /* |
1907 | * ret is already 0 or 1, matching the result of |
1908 | * a btrfs_bin_search() call, so there is no need |
1909 | * to adjust it. |
1910 | */ |
1911 | do_bin_search = false; |
1912 | path->slots[0] = 0; |
1913 | } |
1914 | } |
1915 | } |
1916 | |
1917 | if (do_bin_search) { |
1918 | ret = search_for_key_slot(eb: leaf, search_low_slot, key, |
1919 | prev_cmp, slot: &path->slots[0]); |
1920 | if (ret < 0) |
1921 | return ret; |
1922 | } |
1923 | |
1924 | if (ins_len > 0) { |
1925 | /* |
1926 | * Item key already exists. In this case, if we are allowed to |
1927 | * insert the item (for example, in dir_item case, item key |
1928 | * collision is allowed), it will be merged with the original |
1929 | * item. Only the item size grows, no new btrfs item will be |
1930 | * added. If search_for_extension is not set, ins_len already |
1931 | * accounts the size btrfs_item, deduct it here so leaf space |
1932 | * check will be correct. |
1933 | */ |
1934 | if (ret == 0 && !path->search_for_extension) { |
1935 | ASSERT(ins_len >= sizeof(struct btrfs_item)); |
1936 | ins_len -= sizeof(struct btrfs_item); |
1937 | } |
1938 | |
1939 | ASSERT(leaf_free_space >= 0); |
1940 | |
1941 | if (leaf_free_space < ins_len) { |
1942 | int err; |
1943 | |
1944 | err = split_leaf(trans, root, ins_key: key, path, data_size: ins_len, |
1945 | extend: (ret == 0)); |
1946 | ASSERT(err <= 0); |
1947 | if (WARN_ON(err > 0)) |
1948 | err = -EUCLEAN; |
1949 | if (err) |
1950 | ret = err; |
1951 | } |
1952 | } |
1953 | |
1954 | return ret; |
1955 | } |
1956 | |
1957 | /* |
1958 | * Look for a key in a tree and perform necessary modifications to preserve |
1959 | * tree invariants. |
1960 | * |
1961 | * @trans: Handle of transaction, used when modifying the tree |
1962 | * @p: Holds all btree nodes along the search path |
1963 | * @root: The root node of the tree |
1964 | * @key: The key we are looking for |
1965 | * @ins_len: Indicates purpose of search: |
1966 | * >0 for inserts it's size of item inserted (*) |
1967 | * <0 for deletions |
1968 | * 0 for plain searches, not modifying the tree |
1969 | * |
1970 | * (*) If size of item inserted doesn't include |
1971 | * sizeof(struct btrfs_item), then p->search_for_extension must |
1972 | * be set. |
1973 | * @cow: boolean should CoW operations be performed. Must always be 1 |
1974 | * when modifying the tree. |
1975 | * |
1976 | * If @ins_len > 0, nodes and leaves will be split as we walk down the tree. |
1977 | * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible) |
1978 | * |
1979 | * If @key is found, 0 is returned and you can find the item in the leaf level |
1980 | * of the path (level 0) |
1981 | * |
1982 | * If @key isn't found, 1 is returned and the leaf level of the path (level 0) |
1983 | * points to the slot where it should be inserted |
1984 | * |
1985 | * If an error is encountered while searching the tree a negative error number |
1986 | * is returned |
1987 | */ |
1988 | int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
1989 | const struct btrfs_key *key, struct btrfs_path *p, |
1990 | int ins_len, int cow) |
1991 | { |
1992 | struct btrfs_fs_info *fs_info = root->fs_info; |
1993 | struct extent_buffer *b; |
1994 | int slot; |
1995 | int ret; |
1996 | int err; |
1997 | int level; |
1998 | int lowest_unlock = 1; |
1999 | /* everything at write_lock_level or lower must be write locked */ |
2000 | int write_lock_level = 0; |
2001 | u8 lowest_level = 0; |
2002 | int min_write_lock_level; |
2003 | int prev_cmp; |
2004 | |
2005 | might_sleep(); |
2006 | |
2007 | lowest_level = p->lowest_level; |
2008 | WARN_ON(lowest_level && ins_len > 0); |
2009 | WARN_ON(p->nodes[0] != NULL); |
2010 | BUG_ON(!cow && ins_len); |
2011 | |
2012 | /* |
2013 | * For now only allow nowait for read only operations. There's no |
2014 | * strict reason why we can't, we just only need it for reads so it's |
2015 | * only implemented for reads. |
2016 | */ |
2017 | ASSERT(!p->nowait || !cow); |
2018 | |
2019 | if (ins_len < 0) { |
2020 | lowest_unlock = 2; |
2021 | |
2022 | /* when we are removing items, we might have to go up to level |
2023 | * two as we update tree pointers Make sure we keep write |
2024 | * for those levels as well |
2025 | */ |
2026 | write_lock_level = 2; |
2027 | } else if (ins_len > 0) { |
2028 | /* |
2029 | * for inserting items, make sure we have a write lock on |
2030 | * level 1 so we can update keys |
2031 | */ |
2032 | write_lock_level = 1; |
2033 | } |
2034 | |
2035 | if (!cow) |
2036 | write_lock_level = -1; |
2037 | |
2038 | if (cow && (p->keep_locks || p->lowest_level)) |
2039 | write_lock_level = BTRFS_MAX_LEVEL; |
2040 | |
2041 | min_write_lock_level = write_lock_level; |
2042 | |
2043 | if (p->need_commit_sem) { |
2044 | ASSERT(p->search_commit_root); |
2045 | if (p->nowait) { |
2046 | if (!down_read_trylock(sem: &fs_info->commit_root_sem)) |
2047 | return -EAGAIN; |
2048 | } else { |
2049 | down_read(sem: &fs_info->commit_root_sem); |
2050 | } |
2051 | } |
2052 | |
2053 | again: |
2054 | prev_cmp = -1; |
2055 | b = btrfs_search_slot_get_root(root, p, write_lock_level); |
2056 | if (IS_ERR(ptr: b)) { |
2057 | ret = PTR_ERR(ptr: b); |
2058 | goto done; |
2059 | } |
2060 | |
2061 | while (b) { |
2062 | int dec = 0; |
2063 | |
2064 | level = btrfs_header_level(eb: b); |
2065 | |
2066 | if (cow) { |
2067 | bool last_level = (level == (BTRFS_MAX_LEVEL - 1)); |
2068 | |
2069 | /* |
2070 | * if we don't really need to cow this block |
2071 | * then we don't want to set the path blocking, |
2072 | * so we test it here |
2073 | */ |
2074 | if (!should_cow_block(trans, root, buf: b)) |
2075 | goto cow_done; |
2076 | |
2077 | /* |
2078 | * must have write locks on this node and the |
2079 | * parent |
2080 | */ |
2081 | if (level > write_lock_level || |
2082 | (level + 1 > write_lock_level && |
2083 | level + 1 < BTRFS_MAX_LEVEL && |
2084 | p->nodes[level + 1])) { |
2085 | write_lock_level = level + 1; |
2086 | btrfs_release_path(p); |
2087 | goto again; |
2088 | } |
2089 | |
2090 | if (last_level) |
2091 | err = btrfs_cow_block(trans, root, buf: b, NULL, parent_slot: 0, |
2092 | cow_ret: &b, |
2093 | nest: BTRFS_NESTING_COW); |
2094 | else |
2095 | err = btrfs_cow_block(trans, root, buf: b, |
2096 | parent: p->nodes[level + 1], |
2097 | parent_slot: p->slots[level + 1], cow_ret: &b, |
2098 | nest: BTRFS_NESTING_COW); |
2099 | if (err) { |
2100 | ret = err; |
2101 | goto done; |
2102 | } |
2103 | } |
2104 | cow_done: |
2105 | p->nodes[level] = b; |
2106 | |
2107 | /* |
2108 | * we have a lock on b and as long as we aren't changing |
2109 | * the tree, there is no way to for the items in b to change. |
2110 | * It is safe to drop the lock on our parent before we |
2111 | * go through the expensive btree search on b. |
2112 | * |
2113 | * If we're inserting or deleting (ins_len != 0), then we might |
2114 | * be changing slot zero, which may require changing the parent. |
2115 | * So, we can't drop the lock until after we know which slot |
2116 | * we're operating on. |
2117 | */ |
2118 | if (!ins_len && !p->keep_locks) { |
2119 | int u = level + 1; |
2120 | |
2121 | if (u < BTRFS_MAX_LEVEL && p->locks[u]) { |
2122 | btrfs_tree_unlock_rw(eb: p->nodes[u], rw: p->locks[u]); |
2123 | p->locks[u] = 0; |
2124 | } |
2125 | } |
2126 | |
2127 | if (level == 0) { |
2128 | if (ins_len > 0) |
2129 | ASSERT(write_lock_level >= 1); |
2130 | |
2131 | ret = search_leaf(trans, root, key, path: p, ins_len, prev_cmp); |
2132 | if (!p->search_for_split) |
2133 | unlock_up(path: p, level, lowest_unlock, |
2134 | min_write_lock_level, NULL); |
2135 | goto done; |
2136 | } |
2137 | |
2138 | ret = search_for_key_slot(eb: b, search_low_slot: 0, key, prev_cmp, slot: &slot); |
2139 | if (ret < 0) |
2140 | goto done; |
2141 | prev_cmp = ret; |
2142 | |
2143 | if (ret && slot > 0) { |
2144 | dec = 1; |
2145 | slot--; |
2146 | } |
2147 | p->slots[level] = slot; |
2148 | err = setup_nodes_for_search(trans, root, p, b, level, ins_len, |
2149 | write_lock_level: &write_lock_level); |
2150 | if (err == -EAGAIN) |
2151 | goto again; |
2152 | if (err) { |
2153 | ret = err; |
2154 | goto done; |
2155 | } |
2156 | b = p->nodes[level]; |
2157 | slot = p->slots[level]; |
2158 | |
2159 | /* |
2160 | * Slot 0 is special, if we change the key we have to update |
2161 | * the parent pointer which means we must have a write lock on |
2162 | * the parent |
2163 | */ |
2164 | if (slot == 0 && ins_len && write_lock_level < level + 1) { |
2165 | write_lock_level = level + 1; |
2166 | btrfs_release_path(p); |
2167 | goto again; |
2168 | } |
2169 | |
2170 | unlock_up(path: p, level, lowest_unlock, min_write_lock_level, |
2171 | write_lock_level: &write_lock_level); |
2172 | |
2173 | if (level == lowest_level) { |
2174 | if (dec) |
2175 | p->slots[level]++; |
2176 | goto done; |
2177 | } |
2178 | |
2179 | err = read_block_for_search(root, p, eb_ret: &b, level, slot, key); |
2180 | if (err == -EAGAIN) |
2181 | goto again; |
2182 | if (err) { |
2183 | ret = err; |
2184 | goto done; |
2185 | } |
2186 | |
2187 | if (!p->skip_locking) { |
2188 | level = btrfs_header_level(eb: b); |
2189 | |
2190 | btrfs_maybe_reset_lockdep_class(root, eb: b); |
2191 | |
2192 | if (level <= write_lock_level) { |
2193 | btrfs_tree_lock(eb: b); |
2194 | p->locks[level] = BTRFS_WRITE_LOCK; |
2195 | } else { |
2196 | if (p->nowait) { |
2197 | if (!btrfs_try_tree_read_lock(eb: b)) { |
2198 | free_extent_buffer(eb: b); |
2199 | ret = -EAGAIN; |
2200 | goto done; |
2201 | } |
2202 | } else { |
2203 | btrfs_tree_read_lock(eb: b); |
2204 | } |
2205 | p->locks[level] = BTRFS_READ_LOCK; |
2206 | } |
2207 | p->nodes[level] = b; |
2208 | } |
2209 | } |
2210 | ret = 1; |
2211 | done: |
2212 | if (ret < 0 && !p->skip_release_on_error) |
2213 | btrfs_release_path(p); |
2214 | |
2215 | if (p->need_commit_sem) { |
2216 | int ret2; |
2217 | |
2218 | ret2 = finish_need_commit_sem_search(path: p); |
2219 | up_read(sem: &fs_info->commit_root_sem); |
2220 | if (ret2) |
2221 | ret = ret2; |
2222 | } |
2223 | |
2224 | return ret; |
2225 | } |
2226 | ALLOW_ERROR_INJECTION(btrfs_search_slot, ERRNO); |
2227 | |
2228 | /* |
2229 | * Like btrfs_search_slot, this looks for a key in the given tree. It uses the |
2230 | * current state of the tree together with the operations recorded in the tree |
2231 | * modification log to search for the key in a previous version of this tree, as |
2232 | * denoted by the time_seq parameter. |
2233 | * |
2234 | * Naturally, there is no support for insert, delete or cow operations. |
2235 | * |
2236 | * The resulting path and return value will be set up as if we called |
2237 | * btrfs_search_slot at that point in time with ins_len and cow both set to 0. |
2238 | */ |
2239 | int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key, |
2240 | struct btrfs_path *p, u64 time_seq) |
2241 | { |
2242 | struct btrfs_fs_info *fs_info = root->fs_info; |
2243 | struct extent_buffer *b; |
2244 | int slot; |
2245 | int ret; |
2246 | int err; |
2247 | int level; |
2248 | int lowest_unlock = 1; |
2249 | u8 lowest_level = 0; |
2250 | |
2251 | lowest_level = p->lowest_level; |
2252 | WARN_ON(p->nodes[0] != NULL); |
2253 | ASSERT(!p->nowait); |
2254 | |
2255 | if (p->search_commit_root) { |
2256 | BUG_ON(time_seq); |
2257 | return btrfs_search_slot(NULL, root, key, p, ins_len: 0, cow: 0); |
2258 | } |
2259 | |
2260 | again: |
2261 | b = btrfs_get_old_root(root, time_seq); |
2262 | if (!b) { |
2263 | ret = -EIO; |
2264 | goto done; |
2265 | } |
2266 | level = btrfs_header_level(eb: b); |
2267 | p->locks[level] = BTRFS_READ_LOCK; |
2268 | |
2269 | while (b) { |
2270 | int dec = 0; |
2271 | |
2272 | level = btrfs_header_level(eb: b); |
2273 | p->nodes[level] = b; |
2274 | |
2275 | /* |
2276 | * we have a lock on b and as long as we aren't changing |
2277 | * the tree, there is no way to for the items in b to change. |
2278 | * It is safe to drop the lock on our parent before we |
2279 | * go through the expensive btree search on b. |
2280 | */ |
2281 | btrfs_unlock_up_safe(path: p, level: level + 1); |
2282 | |
2283 | ret = btrfs_bin_search(eb: b, first_slot: 0, key, slot: &slot); |
2284 | if (ret < 0) |
2285 | goto done; |
2286 | |
2287 | if (level == 0) { |
2288 | p->slots[level] = slot; |
2289 | unlock_up(path: p, level, lowest_unlock, min_write_lock_level: 0, NULL); |
2290 | goto done; |
2291 | } |
2292 | |
2293 | if (ret && slot > 0) { |
2294 | dec = 1; |
2295 | slot--; |
2296 | } |
2297 | p->slots[level] = slot; |
2298 | unlock_up(path: p, level, lowest_unlock, min_write_lock_level: 0, NULL); |
2299 | |
2300 | if (level == lowest_level) { |
2301 | if (dec) |
2302 | p->slots[level]++; |
2303 | goto done; |
2304 | } |
2305 | |
2306 | err = read_block_for_search(root, p, eb_ret: &b, level, slot, key); |
2307 | if (err == -EAGAIN) |
2308 | goto again; |
2309 | if (err) { |
2310 | ret = err; |
2311 | goto done; |
2312 | } |
2313 | |
2314 | level = btrfs_header_level(eb: b); |
2315 | btrfs_tree_read_lock(eb: b); |
2316 | b = btrfs_tree_mod_log_rewind(fs_info, path: p, eb: b, time_seq); |
2317 | if (!b) { |
2318 | ret = -ENOMEM; |
2319 | goto done; |
2320 | } |
2321 | p->locks[level] = BTRFS_READ_LOCK; |
2322 | p->nodes[level] = b; |
2323 | } |
2324 | ret = 1; |
2325 | done: |
2326 | if (ret < 0) |
2327 | btrfs_release_path(p); |
2328 | |
2329 | return ret; |
2330 | } |
2331 | |
2332 | /* |
2333 | * Search the tree again to find a leaf with smaller keys. |
2334 | * Returns 0 if it found something. |
2335 | * Returns 1 if there are no smaller keys. |
2336 | * Returns < 0 on error. |
2337 | * |
2338 | * This may release the path, and so you may lose any locks held at the |
2339 | * time you call it. |
2340 | */ |
2341 | static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) |
2342 | { |
2343 | struct btrfs_key key; |
2344 | struct btrfs_key orig_key; |
2345 | struct btrfs_disk_key found_key; |
2346 | int ret; |
2347 | |
2348 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: 0); |
2349 | orig_key = key; |
2350 | |
2351 | if (key.offset > 0) { |
2352 | key.offset--; |
2353 | } else if (key.type > 0) { |
2354 | key.type--; |
2355 | key.offset = (u64)-1; |
2356 | } else if (key.objectid > 0) { |
2357 | key.objectid--; |
2358 | key.type = (u8)-1; |
2359 | key.offset = (u64)-1; |
2360 | } else { |
2361 | return 1; |
2362 | } |
2363 | |
2364 | btrfs_release_path(p: path); |
2365 | ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0); |
2366 | if (ret <= 0) |
2367 | return ret; |
2368 | |
2369 | /* |
2370 | * Previous key not found. Even if we were at slot 0 of the leaf we had |
2371 | * before releasing the path and calling btrfs_search_slot(), we now may |
2372 | * be in a slot pointing to the same original key - this can happen if |
2373 | * after we released the path, one of more items were moved from a |
2374 | * sibling leaf into the front of the leaf we had due to an insertion |
2375 | * (see push_leaf_right()). |
2376 | * If we hit this case and our slot is > 0 and just decrement the slot |
2377 | * so that the caller does not process the same key again, which may or |
2378 | * may not break the caller, depending on its logic. |
2379 | */ |
2380 | if (path->slots[0] < btrfs_header_nritems(eb: path->nodes[0])) { |
2381 | btrfs_item_key(eb: path->nodes[0], disk_key: &found_key, nr: path->slots[0]); |
2382 | ret = btrfs_comp_keys(disk_key: &found_key, k2: &orig_key); |
2383 | if (ret == 0) { |
2384 | if (path->slots[0] > 0) { |
2385 | path->slots[0]--; |
2386 | return 0; |
2387 | } |
2388 | /* |
2389 | * At slot 0, same key as before, it means orig_key is |
2390 | * the lowest, leftmost, key in the tree. We're done. |
2391 | */ |
2392 | return 1; |
2393 | } |
2394 | } |
2395 | |
2396 | btrfs_item_key(eb: path->nodes[0], disk_key: &found_key, nr: 0); |
2397 | ret = btrfs_comp_keys(disk_key: &found_key, k2: &key); |
2398 | /* |
2399 | * We might have had an item with the previous key in the tree right |
2400 | * before we released our path. And after we released our path, that |
2401 | * item might have been pushed to the first slot (0) of the leaf we |
2402 | * were holding due to a tree balance. Alternatively, an item with the |
2403 | * previous key can exist as the only element of a leaf (big fat item). |
2404 | * Therefore account for these 2 cases, so that our callers (like |
2405 | * btrfs_previous_item) don't miss an existing item with a key matching |
2406 | * the previous key we computed above. |
2407 | */ |
2408 | if (ret <= 0) |
2409 | return 0; |
2410 | return 1; |
2411 | } |
2412 | |
2413 | /* |
2414 | * helper to use instead of search slot if no exact match is needed but |
2415 | * instead the next or previous item should be returned. |
2416 | * When find_higher is true, the next higher item is returned, the next lower |
2417 | * otherwise. |
2418 | * When return_any and find_higher are both true, and no higher item is found, |
2419 | * return the next lower instead. |
2420 | * When return_any is true and find_higher is false, and no lower item is found, |
2421 | * return the next higher instead. |
2422 | * It returns 0 if any item is found, 1 if none is found (tree empty), and |
2423 | * < 0 on error |
2424 | */ |
2425 | int btrfs_search_slot_for_read(struct btrfs_root *root, |
2426 | const struct btrfs_key *key, |
2427 | struct btrfs_path *p, int find_higher, |
2428 | int return_any) |
2429 | { |
2430 | int ret; |
2431 | struct extent_buffer *leaf; |
2432 | |
2433 | again: |
2434 | ret = btrfs_search_slot(NULL, root, key, p, ins_len: 0, cow: 0); |
2435 | if (ret <= 0) |
2436 | return ret; |
2437 | /* |
2438 | * a return value of 1 means the path is at the position where the |
2439 | * item should be inserted. Normally this is the next bigger item, |
2440 | * but in case the previous item is the last in a leaf, path points |
2441 | * to the first free slot in the previous leaf, i.e. at an invalid |
2442 | * item. |
2443 | */ |
2444 | leaf = p->nodes[0]; |
2445 | |
2446 | if (find_higher) { |
2447 | if (p->slots[0] >= btrfs_header_nritems(eb: leaf)) { |
2448 | ret = btrfs_next_leaf(root, path: p); |
2449 | if (ret <= 0) |
2450 | return ret; |
2451 | if (!return_any) |
2452 | return 1; |
2453 | /* |
2454 | * no higher item found, return the next |
2455 | * lower instead |
2456 | */ |
2457 | return_any = 0; |
2458 | find_higher = 0; |
2459 | btrfs_release_path(p); |
2460 | goto again; |
2461 | } |
2462 | } else { |
2463 | if (p->slots[0] == 0) { |
2464 | ret = btrfs_prev_leaf(root, path: p); |
2465 | if (ret < 0) |
2466 | return ret; |
2467 | if (!ret) { |
2468 | leaf = p->nodes[0]; |
2469 | if (p->slots[0] == btrfs_header_nritems(eb: leaf)) |
2470 | p->slots[0]--; |
2471 | return 0; |
2472 | } |
2473 | if (!return_any) |
2474 | return 1; |
2475 | /* |
2476 | * no lower item found, return the next |
2477 | * higher instead |
2478 | */ |
2479 | return_any = 0; |
2480 | find_higher = 1; |
2481 | btrfs_release_path(p); |
2482 | goto again; |
2483 | } else { |
2484 | --p->slots[0]; |
2485 | } |
2486 | } |
2487 | return 0; |
2488 | } |
2489 | |
2490 | /* |
2491 | * Execute search and call btrfs_previous_item to traverse backwards if the item |
2492 | * was not found. |
2493 | * |
2494 | * Return 0 if found, 1 if not found and < 0 if error. |
2495 | */ |
2496 | int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, |
2497 | struct btrfs_path *path) |
2498 | { |
2499 | int ret; |
2500 | |
2501 | ret = btrfs_search_slot(NULL, root, key, p: path, ins_len: 0, cow: 0); |
2502 | if (ret > 0) |
2503 | ret = btrfs_previous_item(root, path, min_objectid: key->objectid, type: key->type); |
2504 | |
2505 | if (ret == 0) |
2506 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: key, nr: path->slots[0]); |
2507 | |
2508 | return ret; |
2509 | } |
2510 | |
2511 | /* |
2512 | * Search for a valid slot for the given path. |
2513 | * |
2514 | * @root: The root node of the tree. |
2515 | * @key: Will contain a valid item if found. |
2516 | * @path: The starting point to validate the slot. |
2517 | * |
2518 | * Return: 0 if the item is valid |
2519 | * 1 if not found |
2520 | * <0 if error. |
2521 | */ |
2522 | int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, |
2523 | struct btrfs_path *path) |
2524 | { |
2525 | if (path->slots[0] >= btrfs_header_nritems(eb: path->nodes[0])) { |
2526 | int ret; |
2527 | |
2528 | ret = btrfs_next_leaf(root, path); |
2529 | if (ret) |
2530 | return ret; |
2531 | } |
2532 | |
2533 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: key, nr: path->slots[0]); |
2534 | return 0; |
2535 | } |
2536 | |
2537 | /* |
2538 | * adjust the pointers going up the tree, starting at level |
2539 | * making sure the right key of each node is points to 'key'. |
2540 | * This is used after shifting pointers to the left, so it stops |
2541 | * fixing up pointers when a given leaf/node is not in slot 0 of the |
2542 | * higher levels |
2543 | * |
2544 | */ |
2545 | static void fixup_low_keys(struct btrfs_trans_handle *trans, |
2546 | struct btrfs_path *path, |
2547 | struct btrfs_disk_key *key, int level) |
2548 | { |
2549 | int i; |
2550 | struct extent_buffer *t; |
2551 | int ret; |
2552 | |
2553 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
2554 | int tslot = path->slots[i]; |
2555 | |
2556 | if (!path->nodes[i]) |
2557 | break; |
2558 | t = path->nodes[i]; |
2559 | ret = btrfs_tree_mod_log_insert_key(eb: t, slot: tslot, |
2560 | op: BTRFS_MOD_LOG_KEY_REPLACE); |
2561 | BUG_ON(ret < 0); |
2562 | btrfs_set_node_key(eb: t, disk_key: key, nr: tslot); |
2563 | btrfs_mark_buffer_dirty(trans, buf: path->nodes[i]); |
2564 | if (tslot != 0) |
2565 | break; |
2566 | } |
2567 | } |
2568 | |
2569 | /* |
2570 | * update item key. |
2571 | * |
2572 | * This function isn't completely safe. It's the caller's responsibility |
2573 | * that the new key won't break the order |
2574 | */ |
2575 | void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, |
2576 | struct btrfs_path *path, |
2577 | const struct btrfs_key *new_key) |
2578 | { |
2579 | struct btrfs_fs_info *fs_info = trans->fs_info; |
2580 | struct btrfs_disk_key disk_key; |
2581 | struct extent_buffer *eb; |
2582 | int slot; |
2583 | |
2584 | eb = path->nodes[0]; |
2585 | slot = path->slots[0]; |
2586 | if (slot > 0) { |
2587 | btrfs_item_key(eb, disk_key: &disk_key, nr: slot - 1); |
2588 | if (unlikely(btrfs_comp_keys(&disk_key, new_key) >= 0)) { |
2589 | btrfs_print_leaf(l: eb); |
2590 | btrfs_crit(fs_info, |
2591 | "slot %u key (%llu %u %llu) new key (%llu %u %llu)" , |
2592 | slot, btrfs_disk_key_objectid(&disk_key), |
2593 | btrfs_disk_key_type(&disk_key), |
2594 | btrfs_disk_key_offset(&disk_key), |
2595 | new_key->objectid, new_key->type, |
2596 | new_key->offset); |
2597 | BUG(); |
2598 | } |
2599 | } |
2600 | if (slot < btrfs_header_nritems(eb) - 1) { |
2601 | btrfs_item_key(eb, disk_key: &disk_key, nr: slot + 1); |
2602 | if (unlikely(btrfs_comp_keys(&disk_key, new_key) <= 0)) { |
2603 | btrfs_print_leaf(l: eb); |
2604 | btrfs_crit(fs_info, |
2605 | "slot %u key (%llu %u %llu) new key (%llu %u %llu)" , |
2606 | slot, btrfs_disk_key_objectid(&disk_key), |
2607 | btrfs_disk_key_type(&disk_key), |
2608 | btrfs_disk_key_offset(&disk_key), |
2609 | new_key->objectid, new_key->type, |
2610 | new_key->offset); |
2611 | BUG(); |
2612 | } |
2613 | } |
2614 | |
2615 | btrfs_cpu_key_to_disk(disk_key: &disk_key, cpu_key: new_key); |
2616 | btrfs_set_item_key(eb, disk_key: &disk_key, nr: slot); |
2617 | btrfs_mark_buffer_dirty(trans, buf: eb); |
2618 | if (slot == 0) |
2619 | fixup_low_keys(trans, path, key: &disk_key, level: 1); |
2620 | } |
2621 | |
2622 | /* |
2623 | * Check key order of two sibling extent buffers. |
2624 | * |
2625 | * Return true if something is wrong. |
2626 | * Return false if everything is fine. |
2627 | * |
2628 | * Tree-checker only works inside one tree block, thus the following |
2629 | * corruption can not be detected by tree-checker: |
2630 | * |
2631 | * Leaf @left | Leaf @right |
2632 | * -------------------------------------------------------------- |
2633 | * | 1 | 2 | 3 | 4 | 5 | f6 | | 7 | 8 | |
2634 | * |
2635 | * Key f6 in leaf @left itself is valid, but not valid when the next |
2636 | * key in leaf @right is 7. |
2637 | * This can only be checked at tree block merge time. |
2638 | * And since tree checker has ensured all key order in each tree block |
2639 | * is correct, we only need to bother the last key of @left and the first |
2640 | * key of @right. |
2641 | */ |
2642 | static bool check_sibling_keys(struct extent_buffer *left, |
2643 | struct extent_buffer *right) |
2644 | { |
2645 | struct btrfs_key left_last; |
2646 | struct btrfs_key right_first; |
2647 | int level = btrfs_header_level(eb: left); |
2648 | int nr_left = btrfs_header_nritems(eb: left); |
2649 | int nr_right = btrfs_header_nritems(eb: right); |
2650 | |
2651 | /* No key to check in one of the tree blocks */ |
2652 | if (!nr_left || !nr_right) |
2653 | return false; |
2654 | |
2655 | if (level) { |
2656 | btrfs_node_key_to_cpu(eb: left, cpu_key: &left_last, nr: nr_left - 1); |
2657 | btrfs_node_key_to_cpu(eb: right, cpu_key: &right_first, nr: 0); |
2658 | } else { |
2659 | btrfs_item_key_to_cpu(eb: left, cpu_key: &left_last, nr: nr_left - 1); |
2660 | btrfs_item_key_to_cpu(eb: right, cpu_key: &right_first, nr: 0); |
2661 | } |
2662 | |
2663 | if (unlikely(btrfs_comp_cpu_keys(&left_last, &right_first) >= 0)) { |
2664 | btrfs_crit(left->fs_info, "left extent buffer:" ); |
2665 | btrfs_print_tree(c: left, follow: false); |
2666 | btrfs_crit(left->fs_info, "right extent buffer:" ); |
2667 | btrfs_print_tree(c: right, follow: false); |
2668 | btrfs_crit(left->fs_info, |
2669 | "bad key order, sibling blocks, left last (%llu %u %llu) right first (%llu %u %llu)" , |
2670 | left_last.objectid, left_last.type, |
2671 | left_last.offset, right_first.objectid, |
2672 | right_first.type, right_first.offset); |
2673 | return true; |
2674 | } |
2675 | return false; |
2676 | } |
2677 | |
2678 | /* |
2679 | * try to push data from one node into the next node left in the |
2680 | * tree. |
2681 | * |
2682 | * returns 0 if some ptrs were pushed left, < 0 if there was some horrible |
2683 | * error, and > 0 if there was no room in the left hand block. |
2684 | */ |
2685 | static int push_node_left(struct btrfs_trans_handle *trans, |
2686 | struct extent_buffer *dst, |
2687 | struct extent_buffer *src, int empty) |
2688 | { |
2689 | struct btrfs_fs_info *fs_info = trans->fs_info; |
2690 | int push_items = 0; |
2691 | int src_nritems; |
2692 | int dst_nritems; |
2693 | int ret = 0; |
2694 | |
2695 | src_nritems = btrfs_header_nritems(eb: src); |
2696 | dst_nritems = btrfs_header_nritems(eb: dst); |
2697 | push_items = BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) - dst_nritems; |
2698 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
2699 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
2700 | |
2701 | if (!empty && src_nritems <= 8) |
2702 | return 1; |
2703 | |
2704 | if (push_items <= 0) |
2705 | return 1; |
2706 | |
2707 | if (empty) { |
2708 | push_items = min(src_nritems, push_items); |
2709 | if (push_items < src_nritems) { |
2710 | /* leave at least 8 pointers in the node if |
2711 | * we aren't going to empty it |
2712 | */ |
2713 | if (src_nritems - push_items < 8) { |
2714 | if (push_items <= 8) |
2715 | return 1; |
2716 | push_items -= 8; |
2717 | } |
2718 | } |
2719 | } else |
2720 | push_items = min(src_nritems - 8, push_items); |
2721 | |
2722 | /* dst is the left eb, src is the middle eb */ |
2723 | if (check_sibling_keys(left: dst, right: src)) { |
2724 | ret = -EUCLEAN; |
2725 | btrfs_abort_transaction(trans, ret); |
2726 | return ret; |
2727 | } |
2728 | ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_offset: dst_nritems, src_offset: 0, nr_items: push_items); |
2729 | if (ret) { |
2730 | btrfs_abort_transaction(trans, ret); |
2731 | return ret; |
2732 | } |
2733 | copy_extent_buffer(dst, src, |
2734 | dst_offset: btrfs_node_key_ptr_offset(eb: dst, nr: dst_nritems), |
2735 | src_offset: btrfs_node_key_ptr_offset(eb: src, nr: 0), |
2736 | len: push_items * sizeof(struct btrfs_key_ptr)); |
2737 | |
2738 | if (push_items < src_nritems) { |
2739 | /* |
2740 | * btrfs_tree_mod_log_eb_copy handles logging the move, so we |
2741 | * don't need to do an explicit tree mod log operation for it. |
2742 | */ |
2743 | memmove_extent_buffer(dst: src, dst_offset: btrfs_node_key_ptr_offset(eb: src, nr: 0), |
2744 | src_offset: btrfs_node_key_ptr_offset(eb: src, nr: push_items), |
2745 | len: (src_nritems - push_items) * |
2746 | sizeof(struct btrfs_key_ptr)); |
2747 | } |
2748 | btrfs_set_header_nritems(eb: src, val: src_nritems - push_items); |
2749 | btrfs_set_header_nritems(eb: dst, val: dst_nritems + push_items); |
2750 | btrfs_mark_buffer_dirty(trans, buf: src); |
2751 | btrfs_mark_buffer_dirty(trans, buf: dst); |
2752 | |
2753 | return ret; |
2754 | } |
2755 | |
2756 | /* |
2757 | * try to push data from one node into the next node right in the |
2758 | * tree. |
2759 | * |
2760 | * returns 0 if some ptrs were pushed, < 0 if there was some horrible |
2761 | * error, and > 0 if there was no room in the right hand block. |
2762 | * |
2763 | * this will only push up to 1/2 the contents of the left node over |
2764 | */ |
2765 | static int balance_node_right(struct btrfs_trans_handle *trans, |
2766 | struct extent_buffer *dst, |
2767 | struct extent_buffer *src) |
2768 | { |
2769 | struct btrfs_fs_info *fs_info = trans->fs_info; |
2770 | int push_items = 0; |
2771 | int max_push; |
2772 | int src_nritems; |
2773 | int dst_nritems; |
2774 | int ret = 0; |
2775 | |
2776 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
2777 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
2778 | |
2779 | src_nritems = btrfs_header_nritems(eb: src); |
2780 | dst_nritems = btrfs_header_nritems(eb: dst); |
2781 | push_items = BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) - dst_nritems; |
2782 | if (push_items <= 0) |
2783 | return 1; |
2784 | |
2785 | if (src_nritems < 4) |
2786 | return 1; |
2787 | |
2788 | max_push = src_nritems / 2 + 1; |
2789 | /* don't try to empty the node */ |
2790 | if (max_push >= src_nritems) |
2791 | return 1; |
2792 | |
2793 | if (max_push < push_items) |
2794 | push_items = max_push; |
2795 | |
2796 | /* dst is the right eb, src is the middle eb */ |
2797 | if (check_sibling_keys(left: src, right: dst)) { |
2798 | ret = -EUCLEAN; |
2799 | btrfs_abort_transaction(trans, ret); |
2800 | return ret; |
2801 | } |
2802 | |
2803 | /* |
2804 | * btrfs_tree_mod_log_eb_copy handles logging the move, so we don't |
2805 | * need to do an explicit tree mod log operation for it. |
2806 | */ |
2807 | memmove_extent_buffer(dst, dst_offset: btrfs_node_key_ptr_offset(eb: dst, nr: push_items), |
2808 | src_offset: btrfs_node_key_ptr_offset(eb: dst, nr: 0), |
2809 | len: (dst_nritems) * |
2810 | sizeof(struct btrfs_key_ptr)); |
2811 | |
2812 | ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_offset: 0, src_offset: src_nritems - push_items, |
2813 | nr_items: push_items); |
2814 | if (ret) { |
2815 | btrfs_abort_transaction(trans, ret); |
2816 | return ret; |
2817 | } |
2818 | copy_extent_buffer(dst, src, |
2819 | dst_offset: btrfs_node_key_ptr_offset(eb: dst, nr: 0), |
2820 | src_offset: btrfs_node_key_ptr_offset(eb: src, nr: src_nritems - push_items), |
2821 | len: push_items * sizeof(struct btrfs_key_ptr)); |
2822 | |
2823 | btrfs_set_header_nritems(eb: src, val: src_nritems - push_items); |
2824 | btrfs_set_header_nritems(eb: dst, val: dst_nritems + push_items); |
2825 | |
2826 | btrfs_mark_buffer_dirty(trans, buf: src); |
2827 | btrfs_mark_buffer_dirty(trans, buf: dst); |
2828 | |
2829 | return ret; |
2830 | } |
2831 | |
2832 | /* |
2833 | * helper function to insert a new root level in the tree. |
2834 | * A new node is allocated, and a single item is inserted to |
2835 | * point to the existing root |
2836 | * |
2837 | * returns zero on success or < 0 on failure. |
2838 | */ |
2839 | static noinline int insert_new_root(struct btrfs_trans_handle *trans, |
2840 | struct btrfs_root *root, |
2841 | struct btrfs_path *path, int level) |
2842 | { |
2843 | u64 lower_gen; |
2844 | struct extent_buffer *lower; |
2845 | struct extent_buffer *c; |
2846 | struct extent_buffer *old; |
2847 | struct btrfs_disk_key lower_key; |
2848 | int ret; |
2849 | |
2850 | BUG_ON(path->nodes[level]); |
2851 | BUG_ON(path->nodes[level-1] != root->node); |
2852 | |
2853 | lower = path->nodes[level-1]; |
2854 | if (level == 1) |
2855 | btrfs_item_key(eb: lower, disk_key: &lower_key, nr: 0); |
2856 | else |
2857 | btrfs_node_key(eb: lower, disk_key: &lower_key, nr: 0); |
2858 | |
2859 | c = btrfs_alloc_tree_block(trans, root, parent: 0, root_objectid: root->root_key.objectid, |
2860 | key: &lower_key, level, hint: root->node->start, empty_size: 0, |
2861 | reloc_src_root: 0, nest: BTRFS_NESTING_NEW_ROOT); |
2862 | if (IS_ERR(ptr: c)) |
2863 | return PTR_ERR(ptr: c); |
2864 | |
2865 | root_add_used_bytes(root); |
2866 | |
2867 | btrfs_set_header_nritems(eb: c, val: 1); |
2868 | btrfs_set_node_key(eb: c, disk_key: &lower_key, nr: 0); |
2869 | btrfs_set_node_blockptr(eb: c, nr: 0, val: lower->start); |
2870 | lower_gen = btrfs_header_generation(eb: lower); |
2871 | WARN_ON(lower_gen != trans->transid); |
2872 | |
2873 | btrfs_set_node_ptr_generation(eb: c, nr: 0, val: lower_gen); |
2874 | |
2875 | btrfs_mark_buffer_dirty(trans, buf: c); |
2876 | |
2877 | old = root->node; |
2878 | ret = btrfs_tree_mod_log_insert_root(old_root: root->node, new_root: c, log_removal: false); |
2879 | if (ret < 0) { |
2880 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf: c, parent: 0, last_ref: 1); |
2881 | btrfs_tree_unlock(eb: c); |
2882 | free_extent_buffer(eb: c); |
2883 | return ret; |
2884 | } |
2885 | rcu_assign_pointer(root->node, c); |
2886 | |
2887 | /* the super has an extra ref to root->node */ |
2888 | free_extent_buffer(eb: old); |
2889 | |
2890 | add_root_to_dirty_list(root); |
2891 | atomic_inc(v: &c->refs); |
2892 | path->nodes[level] = c; |
2893 | path->locks[level] = BTRFS_WRITE_LOCK; |
2894 | path->slots[level] = 0; |
2895 | return 0; |
2896 | } |
2897 | |
2898 | /* |
2899 | * worker function to insert a single pointer in a node. |
2900 | * the node should have enough room for the pointer already |
2901 | * |
2902 | * slot and level indicate where you want the key to go, and |
2903 | * blocknr is the block the key points to. |
2904 | */ |
2905 | static int insert_ptr(struct btrfs_trans_handle *trans, |
2906 | struct btrfs_path *path, |
2907 | struct btrfs_disk_key *key, u64 bytenr, |
2908 | int slot, int level) |
2909 | { |
2910 | struct extent_buffer *lower; |
2911 | int nritems; |
2912 | int ret; |
2913 | |
2914 | BUG_ON(!path->nodes[level]); |
2915 | btrfs_assert_tree_write_locked(eb: path->nodes[level]); |
2916 | lower = path->nodes[level]; |
2917 | nritems = btrfs_header_nritems(eb: lower); |
2918 | BUG_ON(slot > nritems); |
2919 | BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info)); |
2920 | if (slot != nritems) { |
2921 | if (level) { |
2922 | ret = btrfs_tree_mod_log_insert_move(eb: lower, dst_slot: slot + 1, |
2923 | src_slot: slot, nr_items: nritems - slot); |
2924 | if (ret < 0) { |
2925 | btrfs_abort_transaction(trans, ret); |
2926 | return ret; |
2927 | } |
2928 | } |
2929 | memmove_extent_buffer(dst: lower, |
2930 | dst_offset: btrfs_node_key_ptr_offset(eb: lower, nr: slot + 1), |
2931 | src_offset: btrfs_node_key_ptr_offset(eb: lower, nr: slot), |
2932 | len: (nritems - slot) * sizeof(struct btrfs_key_ptr)); |
2933 | } |
2934 | if (level) { |
2935 | ret = btrfs_tree_mod_log_insert_key(eb: lower, slot, |
2936 | op: BTRFS_MOD_LOG_KEY_ADD); |
2937 | if (ret < 0) { |
2938 | btrfs_abort_transaction(trans, ret); |
2939 | return ret; |
2940 | } |
2941 | } |
2942 | btrfs_set_node_key(eb: lower, disk_key: key, nr: slot); |
2943 | btrfs_set_node_blockptr(eb: lower, nr: slot, val: bytenr); |
2944 | WARN_ON(trans->transid == 0); |
2945 | btrfs_set_node_ptr_generation(eb: lower, nr: slot, val: trans->transid); |
2946 | btrfs_set_header_nritems(eb: lower, val: nritems + 1); |
2947 | btrfs_mark_buffer_dirty(trans, buf: lower); |
2948 | |
2949 | return 0; |
2950 | } |
2951 | |
2952 | /* |
2953 | * split the node at the specified level in path in two. |
2954 | * The path is corrected to point to the appropriate node after the split |
2955 | * |
2956 | * Before splitting this tries to make some room in the node by pushing |
2957 | * left and right, if either one works, it returns right away. |
2958 | * |
2959 | * returns 0 on success and < 0 on failure |
2960 | */ |
2961 | static noinline int split_node(struct btrfs_trans_handle *trans, |
2962 | struct btrfs_root *root, |
2963 | struct btrfs_path *path, int level) |
2964 | { |
2965 | struct btrfs_fs_info *fs_info = root->fs_info; |
2966 | struct extent_buffer *c; |
2967 | struct extent_buffer *split; |
2968 | struct btrfs_disk_key disk_key; |
2969 | int mid; |
2970 | int ret; |
2971 | u32 c_nritems; |
2972 | |
2973 | c = path->nodes[level]; |
2974 | WARN_ON(btrfs_header_generation(c) != trans->transid); |
2975 | if (c == root->node) { |
2976 | /* |
2977 | * trying to split the root, lets make a new one |
2978 | * |
2979 | * tree mod log: We don't log_removal old root in |
2980 | * insert_new_root, because that root buffer will be kept as a |
2981 | * normal node. We are going to log removal of half of the |
2982 | * elements below with btrfs_tree_mod_log_eb_copy(). We're |
2983 | * holding a tree lock on the buffer, which is why we cannot |
2984 | * race with other tree_mod_log users. |
2985 | */ |
2986 | ret = insert_new_root(trans, root, path, level: level + 1); |
2987 | if (ret) |
2988 | return ret; |
2989 | } else { |
2990 | ret = push_nodes_for_insert(trans, root, path, level); |
2991 | c = path->nodes[level]; |
2992 | if (!ret && btrfs_header_nritems(eb: c) < |
2993 | BTRFS_NODEPTRS_PER_BLOCK(info: fs_info) - 3) |
2994 | return 0; |
2995 | if (ret < 0) |
2996 | return ret; |
2997 | } |
2998 | |
2999 | c_nritems = btrfs_header_nritems(eb: c); |
3000 | mid = (c_nritems + 1) / 2; |
3001 | btrfs_node_key(eb: c, disk_key: &disk_key, nr: mid); |
3002 | |
3003 | split = btrfs_alloc_tree_block(trans, root, parent: 0, root_objectid: root->root_key.objectid, |
3004 | key: &disk_key, level, hint: c->start, empty_size: 0, |
3005 | reloc_src_root: 0, nest: BTRFS_NESTING_SPLIT); |
3006 | if (IS_ERR(ptr: split)) |
3007 | return PTR_ERR(ptr: split); |
3008 | |
3009 | root_add_used_bytes(root); |
3010 | ASSERT(btrfs_header_level(c) == level); |
3011 | |
3012 | ret = btrfs_tree_mod_log_eb_copy(dst: split, src: c, dst_offset: 0, src_offset: mid, nr_items: c_nritems - mid); |
3013 | if (ret) { |
3014 | btrfs_tree_unlock(eb: split); |
3015 | free_extent_buffer(eb: split); |
3016 | btrfs_abort_transaction(trans, ret); |
3017 | return ret; |
3018 | } |
3019 | copy_extent_buffer(dst: split, src: c, |
3020 | dst_offset: btrfs_node_key_ptr_offset(eb: split, nr: 0), |
3021 | src_offset: btrfs_node_key_ptr_offset(eb: c, nr: mid), |
3022 | len: (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
3023 | btrfs_set_header_nritems(eb: split, val: c_nritems - mid); |
3024 | btrfs_set_header_nritems(eb: c, val: mid); |
3025 | |
3026 | btrfs_mark_buffer_dirty(trans, buf: c); |
3027 | btrfs_mark_buffer_dirty(trans, buf: split); |
3028 | |
3029 | ret = insert_ptr(trans, path, key: &disk_key, bytenr: split->start, |
3030 | slot: path->slots[level + 1] + 1, level: level + 1); |
3031 | if (ret < 0) { |
3032 | btrfs_tree_unlock(eb: split); |
3033 | free_extent_buffer(eb: split); |
3034 | return ret; |
3035 | } |
3036 | |
3037 | if (path->slots[level] >= mid) { |
3038 | path->slots[level] -= mid; |
3039 | btrfs_tree_unlock(eb: c); |
3040 | free_extent_buffer(eb: c); |
3041 | path->nodes[level] = split; |
3042 | path->slots[level + 1] += 1; |
3043 | } else { |
3044 | btrfs_tree_unlock(eb: split); |
3045 | free_extent_buffer(eb: split); |
3046 | } |
3047 | return 0; |
3048 | } |
3049 | |
3050 | /* |
3051 | * how many bytes are required to store the items in a leaf. start |
3052 | * and nr indicate which items in the leaf to check. This totals up the |
3053 | * space used both by the item structs and the item data |
3054 | */ |
3055 | static int leaf_space_used(const struct extent_buffer *l, int start, int nr) |
3056 | { |
3057 | int data_len; |
3058 | int nritems = btrfs_header_nritems(eb: l); |
3059 | int end = min(nritems, start + nr) - 1; |
3060 | |
3061 | if (!nr) |
3062 | return 0; |
3063 | data_len = btrfs_item_offset(eb: l, slot: start) + btrfs_item_size(eb: l, slot: start); |
3064 | data_len = data_len - btrfs_item_offset(eb: l, slot: end); |
3065 | data_len += sizeof(struct btrfs_item) * nr; |
3066 | WARN_ON(data_len < 0); |
3067 | return data_len; |
3068 | } |
3069 | |
3070 | /* |
3071 | * The space between the end of the leaf items and |
3072 | * the start of the leaf data. IOW, how much room |
3073 | * the leaf has left for both items and data |
3074 | */ |
3075 | int btrfs_leaf_free_space(const struct extent_buffer *leaf) |
3076 | { |
3077 | struct btrfs_fs_info *fs_info = leaf->fs_info; |
3078 | int nritems = btrfs_header_nritems(eb: leaf); |
3079 | int ret; |
3080 | |
3081 | ret = BTRFS_LEAF_DATA_SIZE(info: fs_info) - leaf_space_used(l: leaf, start: 0, nr: nritems); |
3082 | if (ret < 0) { |
3083 | btrfs_crit(fs_info, |
3084 | "leaf free space ret %d, leaf data size %lu, used %d nritems %d" , |
3085 | ret, |
3086 | (unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info), |
3087 | leaf_space_used(leaf, 0, nritems), nritems); |
3088 | } |
3089 | return ret; |
3090 | } |
3091 | |
3092 | /* |
3093 | * min slot controls the lowest index we're willing to push to the |
3094 | * right. We'll push up to and including min_slot, but no lower |
3095 | */ |
3096 | static noinline int __push_leaf_right(struct btrfs_trans_handle *trans, |
3097 | struct btrfs_path *path, |
3098 | int data_size, int empty, |
3099 | struct extent_buffer *right, |
3100 | int free_space, u32 left_nritems, |
3101 | u32 min_slot) |
3102 | { |
3103 | struct btrfs_fs_info *fs_info = right->fs_info; |
3104 | struct extent_buffer *left = path->nodes[0]; |
3105 | struct extent_buffer *upper = path->nodes[1]; |
3106 | struct btrfs_map_token token; |
3107 | struct btrfs_disk_key disk_key; |
3108 | int slot; |
3109 | u32 i; |
3110 | int push_space = 0; |
3111 | int push_items = 0; |
3112 | u32 nr; |
3113 | u32 right_nritems; |
3114 | u32 data_end; |
3115 | u32 this_item_size; |
3116 | |
3117 | if (empty) |
3118 | nr = 0; |
3119 | else |
3120 | nr = max_t(u32, 1, min_slot); |
3121 | |
3122 | if (path->slots[0] >= left_nritems) |
3123 | push_space += data_size; |
3124 | |
3125 | slot = path->slots[1]; |
3126 | i = left_nritems - 1; |
3127 | while (i >= nr) { |
3128 | if (!empty && push_items > 0) { |
3129 | if (path->slots[0] > i) |
3130 | break; |
3131 | if (path->slots[0] == i) { |
3132 | int space = btrfs_leaf_free_space(leaf: left); |
3133 | |
3134 | if (space + push_space * 2 > free_space) |
3135 | break; |
3136 | } |
3137 | } |
3138 | |
3139 | if (path->slots[0] == i) |
3140 | push_space += data_size; |
3141 | |
3142 | this_item_size = btrfs_item_size(eb: left, slot: i); |
3143 | if (this_item_size + sizeof(struct btrfs_item) + |
3144 | push_space > free_space) |
3145 | break; |
3146 | |
3147 | push_items++; |
3148 | push_space += this_item_size + sizeof(struct btrfs_item); |
3149 | if (i == 0) |
3150 | break; |
3151 | i--; |
3152 | } |
3153 | |
3154 | if (push_items == 0) |
3155 | goto out_unlock; |
3156 | |
3157 | WARN_ON(!empty && push_items == left_nritems); |
3158 | |
3159 | /* push left to right */ |
3160 | right_nritems = btrfs_header_nritems(eb: right); |
3161 | |
3162 | push_space = btrfs_item_data_end(eb: left, nr: left_nritems - push_items); |
3163 | push_space -= leaf_data_end(leaf: left); |
3164 | |
3165 | /* make room in the right data area */ |
3166 | data_end = leaf_data_end(leaf: right); |
3167 | memmove_leaf_data(leaf: right, dst_offset: data_end - push_space, src_offset: data_end, |
3168 | len: BTRFS_LEAF_DATA_SIZE(info: fs_info) - data_end); |
3169 | |
3170 | /* copy from the left data area */ |
3171 | copy_leaf_data(dst: right, src: left, dst_offset: BTRFS_LEAF_DATA_SIZE(info: fs_info) - push_space, |
3172 | src_offset: leaf_data_end(leaf: left), len: push_space); |
3173 | |
3174 | memmove_leaf_items(leaf: right, dst_item: push_items, src_item: 0, nr_items: right_nritems); |
3175 | |
3176 | /* copy the items from left to right */ |
3177 | copy_leaf_items(dst: right, src: left, dst_item: 0, src_item: left_nritems - push_items, nr_items: push_items); |
3178 | |
3179 | /* update the item pointers */ |
3180 | btrfs_init_map_token(token: &token, eb: right); |
3181 | right_nritems += push_items; |
3182 | btrfs_set_header_nritems(eb: right, val: right_nritems); |
3183 | push_space = BTRFS_LEAF_DATA_SIZE(info: fs_info); |
3184 | for (i = 0; i < right_nritems; i++) { |
3185 | push_space -= btrfs_token_item_size(token: &token, slot: i); |
3186 | btrfs_set_token_item_offset(token: &token, slot: i, val: push_space); |
3187 | } |
3188 | |
3189 | left_nritems -= push_items; |
3190 | btrfs_set_header_nritems(eb: left, val: left_nritems); |
3191 | |
3192 | if (left_nritems) |
3193 | btrfs_mark_buffer_dirty(trans, buf: left); |
3194 | else |
3195 | btrfs_clear_buffer_dirty(trans, buf: left); |
3196 | |
3197 | btrfs_mark_buffer_dirty(trans, buf: right); |
3198 | |
3199 | btrfs_item_key(eb: right, disk_key: &disk_key, nr: 0); |
3200 | btrfs_set_node_key(eb: upper, disk_key: &disk_key, nr: slot + 1); |
3201 | btrfs_mark_buffer_dirty(trans, buf: upper); |
3202 | |
3203 | /* then fixup the leaf pointer in the path */ |
3204 | if (path->slots[0] >= left_nritems) { |
3205 | path->slots[0] -= left_nritems; |
3206 | if (btrfs_header_nritems(eb: path->nodes[0]) == 0) |
3207 | btrfs_clear_buffer_dirty(trans, buf: path->nodes[0]); |
3208 | btrfs_tree_unlock(eb: path->nodes[0]); |
3209 | free_extent_buffer(eb: path->nodes[0]); |
3210 | path->nodes[0] = right; |
3211 | path->slots[1] += 1; |
3212 | } else { |
3213 | btrfs_tree_unlock(eb: right); |
3214 | free_extent_buffer(eb: right); |
3215 | } |
3216 | return 0; |
3217 | |
3218 | out_unlock: |
3219 | btrfs_tree_unlock(eb: right); |
3220 | free_extent_buffer(eb: right); |
3221 | return 1; |
3222 | } |
3223 | |
3224 | /* |
3225 | * push some data in the path leaf to the right, trying to free up at |
3226 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
3227 | * |
3228 | * returns 1 if the push failed because the other node didn't have enough |
3229 | * room, 0 if everything worked out and < 0 if there were major errors. |
3230 | * |
3231 | * this will push starting from min_slot to the end of the leaf. It won't |
3232 | * push any slot lower than min_slot |
3233 | */ |
3234 | static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root |
3235 | *root, struct btrfs_path *path, |
3236 | int min_data_size, int data_size, |
3237 | int empty, u32 min_slot) |
3238 | { |
3239 | struct extent_buffer *left = path->nodes[0]; |
3240 | struct extent_buffer *right; |
3241 | struct extent_buffer *upper; |
3242 | int slot; |
3243 | int free_space; |
3244 | u32 left_nritems; |
3245 | int ret; |
3246 | |
3247 | if (!path->nodes[1]) |
3248 | return 1; |
3249 | |
3250 | slot = path->slots[1]; |
3251 | upper = path->nodes[1]; |
3252 | if (slot >= btrfs_header_nritems(eb: upper) - 1) |
3253 | return 1; |
3254 | |
3255 | btrfs_assert_tree_write_locked(eb: path->nodes[1]); |
3256 | |
3257 | right = btrfs_read_node_slot(parent: upper, slot: slot + 1); |
3258 | if (IS_ERR(ptr: right)) |
3259 | return PTR_ERR(ptr: right); |
3260 | |
3261 | __btrfs_tree_lock(eb: right, nest: BTRFS_NESTING_RIGHT); |
3262 | |
3263 | free_space = btrfs_leaf_free_space(leaf: right); |
3264 | if (free_space < data_size) |
3265 | goto out_unlock; |
3266 | |
3267 | ret = btrfs_cow_block(trans, root, buf: right, parent: upper, |
3268 | parent_slot: slot + 1, cow_ret: &right, nest: BTRFS_NESTING_RIGHT_COW); |
3269 | if (ret) |
3270 | goto out_unlock; |
3271 | |
3272 | left_nritems = btrfs_header_nritems(eb: left); |
3273 | if (left_nritems == 0) |
3274 | goto out_unlock; |
3275 | |
3276 | if (check_sibling_keys(left, right)) { |
3277 | ret = -EUCLEAN; |
3278 | btrfs_abort_transaction(trans, ret); |
3279 | btrfs_tree_unlock(eb: right); |
3280 | free_extent_buffer(eb: right); |
3281 | return ret; |
3282 | } |
3283 | if (path->slots[0] == left_nritems && !empty) { |
3284 | /* Key greater than all keys in the leaf, right neighbor has |
3285 | * enough room for it and we're not emptying our leaf to delete |
3286 | * it, therefore use right neighbor to insert the new item and |
3287 | * no need to touch/dirty our left leaf. */ |
3288 | btrfs_tree_unlock(eb: left); |
3289 | free_extent_buffer(eb: left); |
3290 | path->nodes[0] = right; |
3291 | path->slots[0] = 0; |
3292 | path->slots[1]++; |
3293 | return 0; |
3294 | } |
3295 | |
3296 | return __push_leaf_right(trans, path, data_size: min_data_size, empty, right, |
3297 | free_space, left_nritems, min_slot); |
3298 | out_unlock: |
3299 | btrfs_tree_unlock(eb: right); |
3300 | free_extent_buffer(eb: right); |
3301 | return 1; |
3302 | } |
3303 | |
3304 | /* |
3305 | * push some data in the path leaf to the left, trying to free up at |
3306 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
3307 | * |
3308 | * max_slot can put a limit on how far into the leaf we'll push items. The |
3309 | * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the |
3310 | * items |
3311 | */ |
3312 | static noinline int __push_leaf_left(struct btrfs_trans_handle *trans, |
3313 | struct btrfs_path *path, int data_size, |
3314 | int empty, struct extent_buffer *left, |
3315 | int free_space, u32 right_nritems, |
3316 | u32 max_slot) |
3317 | { |
3318 | struct btrfs_fs_info *fs_info = left->fs_info; |
3319 | struct btrfs_disk_key disk_key; |
3320 | struct extent_buffer *right = path->nodes[0]; |
3321 | int i; |
3322 | int push_space = 0; |
3323 | int push_items = 0; |
3324 | u32 old_left_nritems; |
3325 | u32 nr; |
3326 | int ret = 0; |
3327 | u32 this_item_size; |
3328 | u32 old_left_item_size; |
3329 | struct btrfs_map_token token; |
3330 | |
3331 | if (empty) |
3332 | nr = min(right_nritems, max_slot); |
3333 | else |
3334 | nr = min(right_nritems - 1, max_slot); |
3335 | |
3336 | for (i = 0; i < nr; i++) { |
3337 | if (!empty && push_items > 0) { |
3338 | if (path->slots[0] < i) |
3339 | break; |
3340 | if (path->slots[0] == i) { |
3341 | int space = btrfs_leaf_free_space(leaf: right); |
3342 | |
3343 | if (space + push_space * 2 > free_space) |
3344 | break; |
3345 | } |
3346 | } |
3347 | |
3348 | if (path->slots[0] == i) |
3349 | push_space += data_size; |
3350 | |
3351 | this_item_size = btrfs_item_size(eb: right, slot: i); |
3352 | if (this_item_size + sizeof(struct btrfs_item) + push_space > |
3353 | free_space) |
3354 | break; |
3355 | |
3356 | push_items++; |
3357 | push_space += this_item_size + sizeof(struct btrfs_item); |
3358 | } |
3359 | |
3360 | if (push_items == 0) { |
3361 | ret = 1; |
3362 | goto out; |
3363 | } |
3364 | WARN_ON(!empty && push_items == btrfs_header_nritems(right)); |
3365 | |
3366 | /* push data from right to left */ |
3367 | copy_leaf_items(dst: left, src: right, dst_item: btrfs_header_nritems(eb: left), src_item: 0, nr_items: push_items); |
3368 | |
3369 | push_space = BTRFS_LEAF_DATA_SIZE(info: fs_info) - |
3370 | btrfs_item_offset(eb: right, slot: push_items - 1); |
3371 | |
3372 | copy_leaf_data(dst: left, src: right, dst_offset: leaf_data_end(leaf: left) - push_space, |
3373 | src_offset: btrfs_item_offset(eb: right, slot: push_items - 1), len: push_space); |
3374 | old_left_nritems = btrfs_header_nritems(eb: left); |
3375 | BUG_ON(old_left_nritems <= 0); |
3376 | |
3377 | btrfs_init_map_token(token: &token, eb: left); |
3378 | old_left_item_size = btrfs_item_offset(eb: left, slot: old_left_nritems - 1); |
3379 | for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { |
3380 | u32 ioff; |
3381 | |
3382 | ioff = btrfs_token_item_offset(token: &token, slot: i); |
3383 | btrfs_set_token_item_offset(token: &token, slot: i, |
3384 | val: ioff - (BTRFS_LEAF_DATA_SIZE(info: fs_info) - old_left_item_size)); |
3385 | } |
3386 | btrfs_set_header_nritems(eb: left, val: old_left_nritems + push_items); |
3387 | |
3388 | /* fixup right node */ |
3389 | if (push_items > right_nritems) |
3390 | WARN(1, KERN_CRIT "push items %d nr %u\n" , push_items, |
3391 | right_nritems); |
3392 | |
3393 | if (push_items < right_nritems) { |
3394 | push_space = btrfs_item_offset(eb: right, slot: push_items - 1) - |
3395 | leaf_data_end(leaf: right); |
3396 | memmove_leaf_data(leaf: right, |
3397 | dst_offset: BTRFS_LEAF_DATA_SIZE(info: fs_info) - push_space, |
3398 | src_offset: leaf_data_end(leaf: right), len: push_space); |
3399 | |
3400 | memmove_leaf_items(leaf: right, dst_item: 0, src_item: push_items, |
3401 | nr_items: btrfs_header_nritems(eb: right) - push_items); |
3402 | } |
3403 | |
3404 | btrfs_init_map_token(token: &token, eb: right); |
3405 | right_nritems -= push_items; |
3406 | btrfs_set_header_nritems(eb: right, val: right_nritems); |
3407 | push_space = BTRFS_LEAF_DATA_SIZE(info: fs_info); |
3408 | for (i = 0; i < right_nritems; i++) { |
3409 | push_space = push_space - btrfs_token_item_size(token: &token, slot: i); |
3410 | btrfs_set_token_item_offset(token: &token, slot: i, val: push_space); |
3411 | } |
3412 | |
3413 | btrfs_mark_buffer_dirty(trans, buf: left); |
3414 | if (right_nritems) |
3415 | btrfs_mark_buffer_dirty(trans, buf: right); |
3416 | else |
3417 | btrfs_clear_buffer_dirty(trans, buf: right); |
3418 | |
3419 | btrfs_item_key(eb: right, disk_key: &disk_key, nr: 0); |
3420 | fixup_low_keys(trans, path, key: &disk_key, level: 1); |
3421 | |
3422 | /* then fixup the leaf pointer in the path */ |
3423 | if (path->slots[0] < push_items) { |
3424 | path->slots[0] += old_left_nritems; |
3425 | btrfs_tree_unlock(eb: path->nodes[0]); |
3426 | free_extent_buffer(eb: path->nodes[0]); |
3427 | path->nodes[0] = left; |
3428 | path->slots[1] -= 1; |
3429 | } else { |
3430 | btrfs_tree_unlock(eb: left); |
3431 | free_extent_buffer(eb: left); |
3432 | path->slots[0] -= push_items; |
3433 | } |
3434 | BUG_ON(path->slots[0] < 0); |
3435 | return ret; |
3436 | out: |
3437 | btrfs_tree_unlock(eb: left); |
3438 | free_extent_buffer(eb: left); |
3439 | return ret; |
3440 | } |
3441 | |
3442 | /* |
3443 | * push some data in the path leaf to the left, trying to free up at |
3444 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
3445 | * |
3446 | * max_slot can put a limit on how far into the leaf we'll push items. The |
3447 | * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the |
3448 | * items |
3449 | */ |
3450 | static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root |
3451 | *root, struct btrfs_path *path, int min_data_size, |
3452 | int data_size, int empty, u32 max_slot) |
3453 | { |
3454 | struct extent_buffer *right = path->nodes[0]; |
3455 | struct extent_buffer *left; |
3456 | int slot; |
3457 | int free_space; |
3458 | u32 right_nritems; |
3459 | int ret = 0; |
3460 | |
3461 | slot = path->slots[1]; |
3462 | if (slot == 0) |
3463 | return 1; |
3464 | if (!path->nodes[1]) |
3465 | return 1; |
3466 | |
3467 | right_nritems = btrfs_header_nritems(eb: right); |
3468 | if (right_nritems == 0) |
3469 | return 1; |
3470 | |
3471 | btrfs_assert_tree_write_locked(eb: path->nodes[1]); |
3472 | |
3473 | left = btrfs_read_node_slot(parent: path->nodes[1], slot: slot - 1); |
3474 | if (IS_ERR(ptr: left)) |
3475 | return PTR_ERR(ptr: left); |
3476 | |
3477 | __btrfs_tree_lock(eb: left, nest: BTRFS_NESTING_LEFT); |
3478 | |
3479 | free_space = btrfs_leaf_free_space(leaf: left); |
3480 | if (free_space < data_size) { |
3481 | ret = 1; |
3482 | goto out; |
3483 | } |
3484 | |
3485 | ret = btrfs_cow_block(trans, root, buf: left, |
3486 | parent: path->nodes[1], parent_slot: slot - 1, cow_ret: &left, |
3487 | nest: BTRFS_NESTING_LEFT_COW); |
3488 | if (ret) { |
3489 | /* we hit -ENOSPC, but it isn't fatal here */ |
3490 | if (ret == -ENOSPC) |
3491 | ret = 1; |
3492 | goto out; |
3493 | } |
3494 | |
3495 | if (check_sibling_keys(left, right)) { |
3496 | ret = -EUCLEAN; |
3497 | btrfs_abort_transaction(trans, ret); |
3498 | goto out; |
3499 | } |
3500 | return __push_leaf_left(trans, path, data_size: min_data_size, empty, left, |
3501 | free_space, right_nritems, max_slot); |
3502 | out: |
3503 | btrfs_tree_unlock(eb: left); |
3504 | free_extent_buffer(eb: left); |
3505 | return ret; |
3506 | } |
3507 | |
3508 | /* |
3509 | * split the path's leaf in two, making sure there is at least data_size |
3510 | * available for the resulting leaf level of the path. |
3511 | */ |
3512 | static noinline int copy_for_split(struct btrfs_trans_handle *trans, |
3513 | struct btrfs_path *path, |
3514 | struct extent_buffer *l, |
3515 | struct extent_buffer *right, |
3516 | int slot, int mid, int nritems) |
3517 | { |
3518 | struct btrfs_fs_info *fs_info = trans->fs_info; |
3519 | int data_copy_size; |
3520 | int rt_data_off; |
3521 | int i; |
3522 | int ret; |
3523 | struct btrfs_disk_key disk_key; |
3524 | struct btrfs_map_token token; |
3525 | |
3526 | nritems = nritems - mid; |
3527 | btrfs_set_header_nritems(eb: right, val: nritems); |
3528 | data_copy_size = btrfs_item_data_end(eb: l, nr: mid) - leaf_data_end(leaf: l); |
3529 | |
3530 | copy_leaf_items(dst: right, src: l, dst_item: 0, src_item: mid, nr_items: nritems); |
3531 | |
3532 | copy_leaf_data(dst: right, src: l, dst_offset: BTRFS_LEAF_DATA_SIZE(info: fs_info) - data_copy_size, |
3533 | src_offset: leaf_data_end(leaf: l), len: data_copy_size); |
3534 | |
3535 | rt_data_off = BTRFS_LEAF_DATA_SIZE(info: fs_info) - btrfs_item_data_end(eb: l, nr: mid); |
3536 | |
3537 | btrfs_init_map_token(token: &token, eb: right); |
3538 | for (i = 0; i < nritems; i++) { |
3539 | u32 ioff; |
3540 | |
3541 | ioff = btrfs_token_item_offset(token: &token, slot: i); |
3542 | btrfs_set_token_item_offset(token: &token, slot: i, val: ioff + rt_data_off); |
3543 | } |
3544 | |
3545 | btrfs_set_header_nritems(eb: l, val: mid); |
3546 | btrfs_item_key(eb: right, disk_key: &disk_key, nr: 0); |
3547 | ret = insert_ptr(trans, path, key: &disk_key, bytenr: right->start, slot: path->slots[1] + 1, level: 1); |
3548 | if (ret < 0) |
3549 | return ret; |
3550 | |
3551 | btrfs_mark_buffer_dirty(trans, buf: right); |
3552 | btrfs_mark_buffer_dirty(trans, buf: l); |
3553 | BUG_ON(path->slots[0] != slot); |
3554 | |
3555 | if (mid <= slot) { |
3556 | btrfs_tree_unlock(eb: path->nodes[0]); |
3557 | free_extent_buffer(eb: path->nodes[0]); |
3558 | path->nodes[0] = right; |
3559 | path->slots[0] -= mid; |
3560 | path->slots[1] += 1; |
3561 | } else { |
3562 | btrfs_tree_unlock(eb: right); |
3563 | free_extent_buffer(eb: right); |
3564 | } |
3565 | |
3566 | BUG_ON(path->slots[0] < 0); |
3567 | |
3568 | return 0; |
3569 | } |
3570 | |
3571 | /* |
3572 | * double splits happen when we need to insert a big item in the middle |
3573 | * of a leaf. A double split can leave us with 3 mostly empty leaves: |
3574 | * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ] |
3575 | * A B C |
3576 | * |
3577 | * We avoid this by trying to push the items on either side of our target |
3578 | * into the adjacent leaves. If all goes well we can avoid the double split |
3579 | * completely. |
3580 | */ |
3581 | static noinline int push_for_double_split(struct btrfs_trans_handle *trans, |
3582 | struct btrfs_root *root, |
3583 | struct btrfs_path *path, |
3584 | int data_size) |
3585 | { |
3586 | int ret; |
3587 | int progress = 0; |
3588 | int slot; |
3589 | u32 nritems; |
3590 | int space_needed = data_size; |
3591 | |
3592 | slot = path->slots[0]; |
3593 | if (slot < btrfs_header_nritems(eb: path->nodes[0])) |
3594 | space_needed -= btrfs_leaf_free_space(leaf: path->nodes[0]); |
3595 | |
3596 | /* |
3597 | * try to push all the items after our slot into the |
3598 | * right leaf |
3599 | */ |
3600 | ret = push_leaf_right(trans, root, path, min_data_size: 1, data_size: space_needed, empty: 0, min_slot: slot); |
3601 | if (ret < 0) |
3602 | return ret; |
3603 | |
3604 | if (ret == 0) |
3605 | progress++; |
3606 | |
3607 | nritems = btrfs_header_nritems(eb: path->nodes[0]); |
3608 | /* |
3609 | * our goal is to get our slot at the start or end of a leaf. If |
3610 | * we've done so we're done |
3611 | */ |
3612 | if (path->slots[0] == 0 || path->slots[0] == nritems) |
3613 | return 0; |
3614 | |
3615 | if (btrfs_leaf_free_space(leaf: path->nodes[0]) >= data_size) |
3616 | return 0; |
3617 | |
3618 | /* try to push all the items before our slot into the next leaf */ |
3619 | slot = path->slots[0]; |
3620 | space_needed = data_size; |
3621 | if (slot > 0) |
3622 | space_needed -= btrfs_leaf_free_space(leaf: path->nodes[0]); |
3623 | ret = push_leaf_left(trans, root, path, min_data_size: 1, data_size: space_needed, empty: 0, max_slot: slot); |
3624 | if (ret < 0) |
3625 | return ret; |
3626 | |
3627 | if (ret == 0) |
3628 | progress++; |
3629 | |
3630 | if (progress) |
3631 | return 0; |
3632 | return 1; |
3633 | } |
3634 | |
3635 | /* |
3636 | * split the path's leaf in two, making sure there is at least data_size |
3637 | * available for the resulting leaf level of the path. |
3638 | * |
3639 | * returns 0 if all went well and < 0 on failure. |
3640 | */ |
3641 | static noinline int split_leaf(struct btrfs_trans_handle *trans, |
3642 | struct btrfs_root *root, |
3643 | const struct btrfs_key *ins_key, |
3644 | struct btrfs_path *path, int data_size, |
3645 | int extend) |
3646 | { |
3647 | struct btrfs_disk_key disk_key; |
3648 | struct extent_buffer *l; |
3649 | u32 nritems; |
3650 | int mid; |
3651 | int slot; |
3652 | struct extent_buffer *right; |
3653 | struct btrfs_fs_info *fs_info = root->fs_info; |
3654 | int ret = 0; |
3655 | int wret; |
3656 | int split; |
3657 | int num_doubles = 0; |
3658 | int tried_avoid_double = 0; |
3659 | |
3660 | l = path->nodes[0]; |
3661 | slot = path->slots[0]; |
3662 | if (extend && data_size + btrfs_item_size(eb: l, slot) + |
3663 | sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(info: fs_info)) |
3664 | return -EOVERFLOW; |
3665 | |
3666 | /* first try to make some room by pushing left and right */ |
3667 | if (data_size && path->nodes[1]) { |
3668 | int space_needed = data_size; |
3669 | |
3670 | if (slot < btrfs_header_nritems(eb: l)) |
3671 | space_needed -= btrfs_leaf_free_space(leaf: l); |
3672 | |
3673 | wret = push_leaf_right(trans, root, path, min_data_size: space_needed, |
3674 | data_size: space_needed, empty: 0, min_slot: 0); |
3675 | if (wret < 0) |
3676 | return wret; |
3677 | if (wret) { |
3678 | space_needed = data_size; |
3679 | if (slot > 0) |
3680 | space_needed -= btrfs_leaf_free_space(leaf: l); |
3681 | wret = push_leaf_left(trans, root, path, min_data_size: space_needed, |
3682 | data_size: space_needed, empty: 0, max_slot: (u32)-1); |
3683 | if (wret < 0) |
3684 | return wret; |
3685 | } |
3686 | l = path->nodes[0]; |
3687 | |
3688 | /* did the pushes work? */ |
3689 | if (btrfs_leaf_free_space(leaf: l) >= data_size) |
3690 | return 0; |
3691 | } |
3692 | |
3693 | if (!path->nodes[1]) { |
3694 | ret = insert_new_root(trans, root, path, level: 1); |
3695 | if (ret) |
3696 | return ret; |
3697 | } |
3698 | again: |
3699 | split = 1; |
3700 | l = path->nodes[0]; |
3701 | slot = path->slots[0]; |
3702 | nritems = btrfs_header_nritems(eb: l); |
3703 | mid = (nritems + 1) / 2; |
3704 | |
3705 | if (mid <= slot) { |
3706 | if (nritems == 1 || |
3707 | leaf_space_used(l, start: mid, nr: nritems - mid) + data_size > |
3708 | BTRFS_LEAF_DATA_SIZE(info: fs_info)) { |
3709 | if (slot >= nritems) { |
3710 | split = 0; |
3711 | } else { |
3712 | mid = slot; |
3713 | if (mid != nritems && |
3714 | leaf_space_used(l, start: mid, nr: nritems - mid) + |
3715 | data_size > BTRFS_LEAF_DATA_SIZE(info: fs_info)) { |
3716 | if (data_size && !tried_avoid_double) |
3717 | goto push_for_double; |
3718 | split = 2; |
3719 | } |
3720 | } |
3721 | } |
3722 | } else { |
3723 | if (leaf_space_used(l, start: 0, nr: mid) + data_size > |
3724 | BTRFS_LEAF_DATA_SIZE(info: fs_info)) { |
3725 | if (!extend && data_size && slot == 0) { |
3726 | split = 0; |
3727 | } else if ((extend || !data_size) && slot == 0) { |
3728 | mid = 1; |
3729 | } else { |
3730 | mid = slot; |
3731 | if (mid != nritems && |
3732 | leaf_space_used(l, start: mid, nr: nritems - mid) + |
3733 | data_size > BTRFS_LEAF_DATA_SIZE(info: fs_info)) { |
3734 | if (data_size && !tried_avoid_double) |
3735 | goto push_for_double; |
3736 | split = 2; |
3737 | } |
3738 | } |
3739 | } |
3740 | } |
3741 | |
3742 | if (split == 0) |
3743 | btrfs_cpu_key_to_disk(disk_key: &disk_key, cpu_key: ins_key); |
3744 | else |
3745 | btrfs_item_key(eb: l, disk_key: &disk_key, nr: mid); |
3746 | |
3747 | /* |
3748 | * We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double |
3749 | * split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES |
3750 | * subclasses, which is 8 at the time of this patch, and we've maxed it |
3751 | * out. In the future we could add a |
3752 | * BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just |
3753 | * use BTRFS_NESTING_NEW_ROOT. |
3754 | */ |
3755 | right = btrfs_alloc_tree_block(trans, root, parent: 0, root_objectid: root->root_key.objectid, |
3756 | key: &disk_key, level: 0, hint: l->start, empty_size: 0, reloc_src_root: 0, |
3757 | nest: num_doubles ? BTRFS_NESTING_NEW_ROOT : |
3758 | BTRFS_NESTING_SPLIT); |
3759 | if (IS_ERR(ptr: right)) |
3760 | return PTR_ERR(ptr: right); |
3761 | |
3762 | root_add_used_bytes(root); |
3763 | |
3764 | if (split == 0) { |
3765 | if (mid <= slot) { |
3766 | btrfs_set_header_nritems(eb: right, val: 0); |
3767 | ret = insert_ptr(trans, path, key: &disk_key, |
3768 | bytenr: right->start, slot: path->slots[1] + 1, level: 1); |
3769 | if (ret < 0) { |
3770 | btrfs_tree_unlock(eb: right); |
3771 | free_extent_buffer(eb: right); |
3772 | return ret; |
3773 | } |
3774 | btrfs_tree_unlock(eb: path->nodes[0]); |
3775 | free_extent_buffer(eb: path->nodes[0]); |
3776 | path->nodes[0] = right; |
3777 | path->slots[0] = 0; |
3778 | path->slots[1] += 1; |
3779 | } else { |
3780 | btrfs_set_header_nritems(eb: right, val: 0); |
3781 | ret = insert_ptr(trans, path, key: &disk_key, |
3782 | bytenr: right->start, slot: path->slots[1], level: 1); |
3783 | if (ret < 0) { |
3784 | btrfs_tree_unlock(eb: right); |
3785 | free_extent_buffer(eb: right); |
3786 | return ret; |
3787 | } |
3788 | btrfs_tree_unlock(eb: path->nodes[0]); |
3789 | free_extent_buffer(eb: path->nodes[0]); |
3790 | path->nodes[0] = right; |
3791 | path->slots[0] = 0; |
3792 | if (path->slots[1] == 0) |
3793 | fixup_low_keys(trans, path, key: &disk_key, level: 1); |
3794 | } |
3795 | /* |
3796 | * We create a new leaf 'right' for the required ins_len and |
3797 | * we'll do btrfs_mark_buffer_dirty() on this leaf after copying |
3798 | * the content of ins_len to 'right'. |
3799 | */ |
3800 | return ret; |
3801 | } |
3802 | |
3803 | ret = copy_for_split(trans, path, l, right, slot, mid, nritems); |
3804 | if (ret < 0) { |
3805 | btrfs_tree_unlock(eb: right); |
3806 | free_extent_buffer(eb: right); |
3807 | return ret; |
3808 | } |
3809 | |
3810 | if (split == 2) { |
3811 | BUG_ON(num_doubles != 0); |
3812 | num_doubles++; |
3813 | goto again; |
3814 | } |
3815 | |
3816 | return 0; |
3817 | |
3818 | push_for_double: |
3819 | push_for_double_split(trans, root, path, data_size); |
3820 | tried_avoid_double = 1; |
3821 | if (btrfs_leaf_free_space(leaf: path->nodes[0]) >= data_size) |
3822 | return 0; |
3823 | goto again; |
3824 | } |
3825 | |
3826 | static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, |
3827 | struct btrfs_root *root, |
3828 | struct btrfs_path *path, int ins_len) |
3829 | { |
3830 | struct btrfs_key key; |
3831 | struct extent_buffer *leaf; |
3832 | struct btrfs_file_extent_item *fi; |
3833 | u64 extent_len = 0; |
3834 | u32 item_size; |
3835 | int ret; |
3836 | |
3837 | leaf = path->nodes[0]; |
3838 | btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]); |
3839 | |
3840 | BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY && |
3841 | key.type != BTRFS_EXTENT_CSUM_KEY); |
3842 | |
3843 | if (btrfs_leaf_free_space(leaf) >= ins_len) |
3844 | return 0; |
3845 | |
3846 | item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]); |
3847 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
3848 | fi = btrfs_item_ptr(leaf, path->slots[0], |
3849 | struct btrfs_file_extent_item); |
3850 | extent_len = btrfs_file_extent_num_bytes(eb: leaf, s: fi); |
3851 | } |
3852 | btrfs_release_path(p: path); |
3853 | |
3854 | path->keep_locks = 1; |
3855 | path->search_for_split = 1; |
3856 | ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: 0, cow: 1); |
3857 | path->search_for_split = 0; |
3858 | if (ret > 0) |
3859 | ret = -EAGAIN; |
3860 | if (ret < 0) |
3861 | goto err; |
3862 | |
3863 | ret = -EAGAIN; |
3864 | leaf = path->nodes[0]; |
3865 | /* if our item isn't there, return now */ |
3866 | if (item_size != btrfs_item_size(eb: leaf, slot: path->slots[0])) |
3867 | goto err; |
3868 | |
3869 | /* the leaf has changed, it now has room. return now */ |
3870 | if (btrfs_leaf_free_space(leaf: path->nodes[0]) >= ins_len) |
3871 | goto err; |
3872 | |
3873 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
3874 | fi = btrfs_item_ptr(leaf, path->slots[0], |
3875 | struct btrfs_file_extent_item); |
3876 | if (extent_len != btrfs_file_extent_num_bytes(eb: leaf, s: fi)) |
3877 | goto err; |
3878 | } |
3879 | |
3880 | ret = split_leaf(trans, root, ins_key: &key, path, data_size: ins_len, extend: 1); |
3881 | if (ret) |
3882 | goto err; |
3883 | |
3884 | path->keep_locks = 0; |
3885 | btrfs_unlock_up_safe(path, level: 1); |
3886 | return 0; |
3887 | err: |
3888 | path->keep_locks = 0; |
3889 | return ret; |
3890 | } |
3891 | |
3892 | static noinline int split_item(struct btrfs_trans_handle *trans, |
3893 | struct btrfs_path *path, |
3894 | const struct btrfs_key *new_key, |
3895 | unsigned long split_offset) |
3896 | { |
3897 | struct extent_buffer *leaf; |
3898 | int orig_slot, slot; |
3899 | char *buf; |
3900 | u32 nritems; |
3901 | u32 item_size; |
3902 | u32 orig_offset; |
3903 | struct btrfs_disk_key disk_key; |
3904 | |
3905 | leaf = path->nodes[0]; |
3906 | /* |
3907 | * Shouldn't happen because the caller must have previously called |
3908 | * setup_leaf_for_split() to make room for the new item in the leaf. |
3909 | */ |
3910 | if (WARN_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item))) |
3911 | return -ENOSPC; |
3912 | |
3913 | orig_slot = path->slots[0]; |
3914 | orig_offset = btrfs_item_offset(eb: leaf, slot: path->slots[0]); |
3915 | item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]); |
3916 | |
3917 | buf = kmalloc(size: item_size, GFP_NOFS); |
3918 | if (!buf) |
3919 | return -ENOMEM; |
3920 | |
3921 | read_extent_buffer(eb: leaf, dst: buf, btrfs_item_ptr_offset(leaf, |
3922 | path->slots[0]), len: item_size); |
3923 | |
3924 | slot = path->slots[0] + 1; |
3925 | nritems = btrfs_header_nritems(eb: leaf); |
3926 | if (slot != nritems) { |
3927 | /* shift the items */ |
3928 | memmove_leaf_items(leaf, dst_item: slot + 1, src_item: slot, nr_items: nritems - slot); |
3929 | } |
3930 | |
3931 | btrfs_cpu_key_to_disk(disk_key: &disk_key, cpu_key: new_key); |
3932 | btrfs_set_item_key(eb: leaf, disk_key: &disk_key, nr: slot); |
3933 | |
3934 | btrfs_set_item_offset(eb: leaf, slot, val: orig_offset); |
3935 | btrfs_set_item_size(eb: leaf, slot, val: item_size - split_offset); |
3936 | |
3937 | btrfs_set_item_offset(eb: leaf, slot: orig_slot, |
3938 | val: orig_offset + item_size - split_offset); |
3939 | btrfs_set_item_size(eb: leaf, slot: orig_slot, val: split_offset); |
3940 | |
3941 | btrfs_set_header_nritems(eb: leaf, val: nritems + 1); |
3942 | |
3943 | /* write the data for the start of the original item */ |
3944 | write_extent_buffer(eb: leaf, src: buf, |
3945 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
3946 | len: split_offset); |
3947 | |
3948 | /* write the data for the new item */ |
3949 | write_extent_buffer(eb: leaf, src: buf + split_offset, |
3950 | btrfs_item_ptr_offset(leaf, slot), |
3951 | len: item_size - split_offset); |
3952 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
3953 | |
3954 | BUG_ON(btrfs_leaf_free_space(leaf) < 0); |
3955 | kfree(objp: buf); |
3956 | return 0; |
3957 | } |
3958 | |
3959 | /* |
3960 | * This function splits a single item into two items, |
3961 | * giving 'new_key' to the new item and splitting the |
3962 | * old one at split_offset (from the start of the item). |
3963 | * |
3964 | * The path may be released by this operation. After |
3965 | * the split, the path is pointing to the old item. The |
3966 | * new item is going to be in the same node as the old one. |
3967 | * |
3968 | * Note, the item being split must be smaller enough to live alone on |
3969 | * a tree block with room for one extra struct btrfs_item |
3970 | * |
3971 | * This allows us to split the item in place, keeping a lock on the |
3972 | * leaf the entire time. |
3973 | */ |
3974 | int btrfs_split_item(struct btrfs_trans_handle *trans, |
3975 | struct btrfs_root *root, |
3976 | struct btrfs_path *path, |
3977 | const struct btrfs_key *new_key, |
3978 | unsigned long split_offset) |
3979 | { |
3980 | int ret; |
3981 | ret = setup_leaf_for_split(trans, root, path, |
3982 | ins_len: sizeof(struct btrfs_item)); |
3983 | if (ret) |
3984 | return ret; |
3985 | |
3986 | ret = split_item(trans, path, new_key, split_offset); |
3987 | return ret; |
3988 | } |
3989 | |
3990 | /* |
3991 | * make the item pointed to by the path smaller. new_size indicates |
3992 | * how small to make it, and from_end tells us if we just chop bytes |
3993 | * off the end of the item or if we shift the item to chop bytes off |
3994 | * the front. |
3995 | */ |
3996 | void btrfs_truncate_item(struct btrfs_trans_handle *trans, |
3997 | struct btrfs_path *path, u32 new_size, int from_end) |
3998 | { |
3999 | int slot; |
4000 | struct extent_buffer *leaf; |
4001 | u32 nritems; |
4002 | unsigned int data_end; |
4003 | unsigned int old_data_start; |
4004 | unsigned int old_size; |
4005 | unsigned int size_diff; |
4006 | int i; |
4007 | struct btrfs_map_token token; |
4008 | |
4009 | leaf = path->nodes[0]; |
4010 | slot = path->slots[0]; |
4011 | |
4012 | old_size = btrfs_item_size(eb: leaf, slot); |
4013 | if (old_size == new_size) |
4014 | return; |
4015 | |
4016 | nritems = btrfs_header_nritems(eb: leaf); |
4017 | data_end = leaf_data_end(leaf); |
4018 | |
4019 | old_data_start = btrfs_item_offset(eb: leaf, slot); |
4020 | |
4021 | size_diff = old_size - new_size; |
4022 | |
4023 | BUG_ON(slot < 0); |
4024 | BUG_ON(slot >= nritems); |
4025 | |
4026 | /* |
4027 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
4028 | */ |
4029 | /* first correct the data pointers */ |
4030 | btrfs_init_map_token(token: &token, eb: leaf); |
4031 | for (i = slot; i < nritems; i++) { |
4032 | u32 ioff; |
4033 | |
4034 | ioff = btrfs_token_item_offset(token: &token, slot: i); |
4035 | btrfs_set_token_item_offset(token: &token, slot: i, val: ioff + size_diff); |
4036 | } |
4037 | |
4038 | /* shift the data */ |
4039 | if (from_end) { |
4040 | memmove_leaf_data(leaf, dst_offset: data_end + size_diff, src_offset: data_end, |
4041 | len: old_data_start + new_size - data_end); |
4042 | } else { |
4043 | struct btrfs_disk_key disk_key; |
4044 | u64 offset; |
4045 | |
4046 | btrfs_item_key(eb: leaf, disk_key: &disk_key, nr: slot); |
4047 | |
4048 | if (btrfs_disk_key_type(s: &disk_key) == BTRFS_EXTENT_DATA_KEY) { |
4049 | unsigned long ptr; |
4050 | struct btrfs_file_extent_item *fi; |
4051 | |
4052 | fi = btrfs_item_ptr(leaf, slot, |
4053 | struct btrfs_file_extent_item); |
4054 | fi = (struct btrfs_file_extent_item *)( |
4055 | (unsigned long)fi - size_diff); |
4056 | |
4057 | if (btrfs_file_extent_type(eb: leaf, s: fi) == |
4058 | BTRFS_FILE_EXTENT_INLINE) { |
4059 | ptr = btrfs_item_ptr_offset(leaf, slot); |
4060 | memmove_extent_buffer(dst: leaf, dst_offset: ptr, |
4061 | src_offset: (unsigned long)fi, |
4062 | BTRFS_FILE_EXTENT_INLINE_DATA_START); |
4063 | } |
4064 | } |
4065 | |
4066 | memmove_leaf_data(leaf, dst_offset: data_end + size_diff, src_offset: data_end, |
4067 | len: old_data_start - data_end); |
4068 | |
4069 | offset = btrfs_disk_key_offset(s: &disk_key); |
4070 | btrfs_set_disk_key_offset(s: &disk_key, val: offset + size_diff); |
4071 | btrfs_set_item_key(eb: leaf, disk_key: &disk_key, nr: slot); |
4072 | if (slot == 0) |
4073 | fixup_low_keys(trans, path, key: &disk_key, level: 1); |
4074 | } |
4075 | |
4076 | btrfs_set_item_size(eb: leaf, slot, val: new_size); |
4077 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
4078 | |
4079 | if (btrfs_leaf_free_space(leaf) < 0) { |
4080 | btrfs_print_leaf(l: leaf); |
4081 | BUG(); |
4082 | } |
4083 | } |
4084 | |
4085 | /* |
4086 | * make the item pointed to by the path bigger, data_size is the added size. |
4087 | */ |
4088 | void btrfs_extend_item(struct btrfs_trans_handle *trans, |
4089 | struct btrfs_path *path, u32 data_size) |
4090 | { |
4091 | int slot; |
4092 | struct extent_buffer *leaf; |
4093 | u32 nritems; |
4094 | unsigned int data_end; |
4095 | unsigned int old_data; |
4096 | unsigned int old_size; |
4097 | int i; |
4098 | struct btrfs_map_token token; |
4099 | |
4100 | leaf = path->nodes[0]; |
4101 | |
4102 | nritems = btrfs_header_nritems(eb: leaf); |
4103 | data_end = leaf_data_end(leaf); |
4104 | |
4105 | if (btrfs_leaf_free_space(leaf) < data_size) { |
4106 | btrfs_print_leaf(l: leaf); |
4107 | BUG(); |
4108 | } |
4109 | slot = path->slots[0]; |
4110 | old_data = btrfs_item_data_end(eb: leaf, nr: slot); |
4111 | |
4112 | BUG_ON(slot < 0); |
4113 | if (slot >= nritems) { |
4114 | btrfs_print_leaf(l: leaf); |
4115 | btrfs_crit(leaf->fs_info, "slot %d too large, nritems %d" , |
4116 | slot, nritems); |
4117 | BUG(); |
4118 | } |
4119 | |
4120 | /* |
4121 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
4122 | */ |
4123 | /* first correct the data pointers */ |
4124 | btrfs_init_map_token(token: &token, eb: leaf); |
4125 | for (i = slot; i < nritems; i++) { |
4126 | u32 ioff; |
4127 | |
4128 | ioff = btrfs_token_item_offset(token: &token, slot: i); |
4129 | btrfs_set_token_item_offset(token: &token, slot: i, val: ioff - data_size); |
4130 | } |
4131 | |
4132 | /* shift the data */ |
4133 | memmove_leaf_data(leaf, dst_offset: data_end - data_size, src_offset: data_end, |
4134 | len: old_data - data_end); |
4135 | |
4136 | data_end = old_data; |
4137 | old_size = btrfs_item_size(eb: leaf, slot); |
4138 | btrfs_set_item_size(eb: leaf, slot, val: old_size + data_size); |
4139 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
4140 | |
4141 | if (btrfs_leaf_free_space(leaf) < 0) { |
4142 | btrfs_print_leaf(l: leaf); |
4143 | BUG(); |
4144 | } |
4145 | } |
4146 | |
4147 | /* |
4148 | * Make space in the node before inserting one or more items. |
4149 | * |
4150 | * @trans: transaction handle |
4151 | * @root: root we are inserting items to |
4152 | * @path: points to the leaf/slot where we are going to insert new items |
4153 | * @batch: information about the batch of items to insert |
4154 | * |
4155 | * Main purpose is to save stack depth by doing the bulk of the work in a |
4156 | * function that doesn't call btrfs_search_slot |
4157 | */ |
4158 | static void setup_items_for_insert(struct btrfs_trans_handle *trans, |
4159 | struct btrfs_root *root, struct btrfs_path *path, |
4160 | const struct btrfs_item_batch *batch) |
4161 | { |
4162 | struct btrfs_fs_info *fs_info = root->fs_info; |
4163 | int i; |
4164 | u32 nritems; |
4165 | unsigned int data_end; |
4166 | struct btrfs_disk_key disk_key; |
4167 | struct extent_buffer *leaf; |
4168 | int slot; |
4169 | struct btrfs_map_token token; |
4170 | u32 total_size; |
4171 | |
4172 | /* |
4173 | * Before anything else, update keys in the parent and other ancestors |
4174 | * if needed, then release the write locks on them, so that other tasks |
4175 | * can use them while we modify the leaf. |
4176 | */ |
4177 | if (path->slots[0] == 0) { |
4178 | btrfs_cpu_key_to_disk(disk_key: &disk_key, cpu_key: &batch->keys[0]); |
4179 | fixup_low_keys(trans, path, key: &disk_key, level: 1); |
4180 | } |
4181 | btrfs_unlock_up_safe(path, level: 1); |
4182 | |
4183 | leaf = path->nodes[0]; |
4184 | slot = path->slots[0]; |
4185 | |
4186 | nritems = btrfs_header_nritems(eb: leaf); |
4187 | data_end = leaf_data_end(leaf); |
4188 | total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); |
4189 | |
4190 | if (btrfs_leaf_free_space(leaf) < total_size) { |
4191 | btrfs_print_leaf(l: leaf); |
4192 | btrfs_crit(fs_info, "not enough freespace need %u have %d" , |
4193 | total_size, btrfs_leaf_free_space(leaf)); |
4194 | BUG(); |
4195 | } |
4196 | |
4197 | btrfs_init_map_token(token: &token, eb: leaf); |
4198 | if (slot != nritems) { |
4199 | unsigned int old_data = btrfs_item_data_end(eb: leaf, nr: slot); |
4200 | |
4201 | if (old_data < data_end) { |
4202 | btrfs_print_leaf(l: leaf); |
4203 | btrfs_crit(fs_info, |
4204 | "item at slot %d with data offset %u beyond data end of leaf %u" , |
4205 | slot, old_data, data_end); |
4206 | BUG(); |
4207 | } |
4208 | /* |
4209 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
4210 | */ |
4211 | /* first correct the data pointers */ |
4212 | for (i = slot; i < nritems; i++) { |
4213 | u32 ioff; |
4214 | |
4215 | ioff = btrfs_token_item_offset(token: &token, slot: i); |
4216 | btrfs_set_token_item_offset(token: &token, slot: i, |
4217 | val: ioff - batch->total_data_size); |
4218 | } |
4219 | /* shift the items */ |
4220 | memmove_leaf_items(leaf, dst_item: slot + batch->nr, src_item: slot, nr_items: nritems - slot); |
4221 | |
4222 | /* shift the data */ |
4223 | memmove_leaf_data(leaf, dst_offset: data_end - batch->total_data_size, |
4224 | src_offset: data_end, len: old_data - data_end); |
4225 | data_end = old_data; |
4226 | } |
4227 | |
4228 | /* setup the item for the new data */ |
4229 | for (i = 0; i < batch->nr; i++) { |
4230 | btrfs_cpu_key_to_disk(disk_key: &disk_key, cpu_key: &batch->keys[i]); |
4231 | btrfs_set_item_key(eb: leaf, disk_key: &disk_key, nr: slot + i); |
4232 | data_end -= batch->data_sizes[i]; |
4233 | btrfs_set_token_item_offset(token: &token, slot: slot + i, val: data_end); |
4234 | btrfs_set_token_item_size(token: &token, slot: slot + i, val: batch->data_sizes[i]); |
4235 | } |
4236 | |
4237 | btrfs_set_header_nritems(eb: leaf, val: nritems + batch->nr); |
4238 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
4239 | |
4240 | if (btrfs_leaf_free_space(leaf) < 0) { |
4241 | btrfs_print_leaf(l: leaf); |
4242 | BUG(); |
4243 | } |
4244 | } |
4245 | |
4246 | /* |
4247 | * Insert a new item into a leaf. |
4248 | * |
4249 | * @trans: Transaction handle. |
4250 | * @root: The root of the btree. |
4251 | * @path: A path pointing to the target leaf and slot. |
4252 | * @key: The key of the new item. |
4253 | * @data_size: The size of the data associated with the new key. |
4254 | */ |
4255 | void btrfs_setup_item_for_insert(struct btrfs_trans_handle *trans, |
4256 | struct btrfs_root *root, |
4257 | struct btrfs_path *path, |
4258 | const struct btrfs_key *key, |
4259 | u32 data_size) |
4260 | { |
4261 | struct btrfs_item_batch batch; |
4262 | |
4263 | batch.keys = key; |
4264 | batch.data_sizes = &data_size; |
4265 | batch.total_data_size = data_size; |
4266 | batch.nr = 1; |
4267 | |
4268 | setup_items_for_insert(trans, root, path, batch: &batch); |
4269 | } |
4270 | |
4271 | /* |
4272 | * Given a key and some data, insert items into the tree. |
4273 | * This does all the path init required, making room in the tree if needed. |
4274 | */ |
4275 | int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, |
4276 | struct btrfs_root *root, |
4277 | struct btrfs_path *path, |
4278 | const struct btrfs_item_batch *batch) |
4279 | { |
4280 | int ret = 0; |
4281 | int slot; |
4282 | u32 total_size; |
4283 | |
4284 | total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); |
4285 | ret = btrfs_search_slot(trans, root, key: &batch->keys[0], p: path, ins_len: total_size, cow: 1); |
4286 | if (ret == 0) |
4287 | return -EEXIST; |
4288 | if (ret < 0) |
4289 | return ret; |
4290 | |
4291 | slot = path->slots[0]; |
4292 | BUG_ON(slot < 0); |
4293 | |
4294 | setup_items_for_insert(trans, root, path, batch); |
4295 | return 0; |
4296 | } |
4297 | |
4298 | /* |
4299 | * Given a key and some data, insert an item into the tree. |
4300 | * This does all the path init required, making room in the tree if needed. |
4301 | */ |
4302 | int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
4303 | const struct btrfs_key *cpu_key, void *data, |
4304 | u32 data_size) |
4305 | { |
4306 | int ret = 0; |
4307 | struct btrfs_path *path; |
4308 | struct extent_buffer *leaf; |
4309 | unsigned long ptr; |
4310 | |
4311 | path = btrfs_alloc_path(); |
4312 | if (!path) |
4313 | return -ENOMEM; |
4314 | ret = btrfs_insert_empty_item(trans, root, path, key: cpu_key, data_size); |
4315 | if (!ret) { |
4316 | leaf = path->nodes[0]; |
4317 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
4318 | write_extent_buffer(eb: leaf, src: data, start: ptr, len: data_size); |
4319 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
4320 | } |
4321 | btrfs_free_path(p: path); |
4322 | return ret; |
4323 | } |
4324 | |
4325 | /* |
4326 | * This function duplicates an item, giving 'new_key' to the new item. |
4327 | * It guarantees both items live in the same tree leaf and the new item is |
4328 | * contiguous with the original item. |
4329 | * |
4330 | * This allows us to split a file extent in place, keeping a lock on the leaf |
4331 | * the entire time. |
4332 | */ |
4333 | int btrfs_duplicate_item(struct btrfs_trans_handle *trans, |
4334 | struct btrfs_root *root, |
4335 | struct btrfs_path *path, |
4336 | const struct btrfs_key *new_key) |
4337 | { |
4338 | struct extent_buffer *leaf; |
4339 | int ret; |
4340 | u32 item_size; |
4341 | |
4342 | leaf = path->nodes[0]; |
4343 | item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]); |
4344 | ret = setup_leaf_for_split(trans, root, path, |
4345 | ins_len: item_size + sizeof(struct btrfs_item)); |
4346 | if (ret) |
4347 | return ret; |
4348 | |
4349 | path->slots[0]++; |
4350 | btrfs_setup_item_for_insert(trans, root, path, key: new_key, data_size: item_size); |
4351 | leaf = path->nodes[0]; |
4352 | memcpy_extent_buffer(dst: leaf, |
4353 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
4354 | btrfs_item_ptr_offset(leaf, path->slots[0] - 1), |
4355 | len: item_size); |
4356 | return 0; |
4357 | } |
4358 | |
4359 | /* |
4360 | * delete the pointer from a given node. |
4361 | * |
4362 | * the tree should have been previously balanced so the deletion does not |
4363 | * empty a node. |
4364 | * |
4365 | * This is exported for use inside btrfs-progs, don't un-export it. |
4366 | */ |
4367 | int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
4368 | struct btrfs_path *path, int level, int slot) |
4369 | { |
4370 | struct extent_buffer *parent = path->nodes[level]; |
4371 | u32 nritems; |
4372 | int ret; |
4373 | |
4374 | nritems = btrfs_header_nritems(eb: parent); |
4375 | if (slot != nritems - 1) { |
4376 | if (level) { |
4377 | ret = btrfs_tree_mod_log_insert_move(eb: parent, dst_slot: slot, |
4378 | src_slot: slot + 1, nr_items: nritems - slot - 1); |
4379 | if (ret < 0) { |
4380 | btrfs_abort_transaction(trans, ret); |
4381 | return ret; |
4382 | } |
4383 | } |
4384 | memmove_extent_buffer(dst: parent, |
4385 | dst_offset: btrfs_node_key_ptr_offset(eb: parent, nr: slot), |
4386 | src_offset: btrfs_node_key_ptr_offset(eb: parent, nr: slot + 1), |
4387 | len: sizeof(struct btrfs_key_ptr) * |
4388 | (nritems - slot - 1)); |
4389 | } else if (level) { |
4390 | ret = btrfs_tree_mod_log_insert_key(eb: parent, slot, |
4391 | op: BTRFS_MOD_LOG_KEY_REMOVE); |
4392 | if (ret < 0) { |
4393 | btrfs_abort_transaction(trans, ret); |
4394 | return ret; |
4395 | } |
4396 | } |
4397 | |
4398 | nritems--; |
4399 | btrfs_set_header_nritems(eb: parent, val: nritems); |
4400 | if (nritems == 0 && parent == root->node) { |
4401 | BUG_ON(btrfs_header_level(root->node) != 1); |
4402 | /* just turn the root into a leaf and break */ |
4403 | btrfs_set_header_level(eb: root->node, val: 0); |
4404 | } else if (slot == 0) { |
4405 | struct btrfs_disk_key disk_key; |
4406 | |
4407 | btrfs_node_key(eb: parent, disk_key: &disk_key, nr: 0); |
4408 | fixup_low_keys(trans, path, key: &disk_key, level: level + 1); |
4409 | } |
4410 | btrfs_mark_buffer_dirty(trans, buf: parent); |
4411 | return 0; |
4412 | } |
4413 | |
4414 | /* |
4415 | * a helper function to delete the leaf pointed to by path->slots[1] and |
4416 | * path->nodes[1]. |
4417 | * |
4418 | * This deletes the pointer in path->nodes[1] and frees the leaf |
4419 | * block extent. zero is returned if it all worked out, < 0 otherwise. |
4420 | * |
4421 | * The path must have already been setup for deleting the leaf, including |
4422 | * all the proper balancing. path->nodes[1] must be locked. |
4423 | */ |
4424 | static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans, |
4425 | struct btrfs_root *root, |
4426 | struct btrfs_path *path, |
4427 | struct extent_buffer *leaf) |
4428 | { |
4429 | int ret; |
4430 | |
4431 | WARN_ON(btrfs_header_generation(leaf) != trans->transid); |
4432 | ret = btrfs_del_ptr(trans, root, path, level: 1, slot: path->slots[1]); |
4433 | if (ret < 0) |
4434 | return ret; |
4435 | |
4436 | /* |
4437 | * btrfs_free_extent is expensive, we want to make sure we |
4438 | * aren't holding any locks when we call it |
4439 | */ |
4440 | btrfs_unlock_up_safe(path, level: 0); |
4441 | |
4442 | root_sub_used_bytes(root); |
4443 | |
4444 | atomic_inc(v: &leaf->refs); |
4445 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf: leaf, parent: 0, last_ref: 1); |
4446 | free_extent_buffer_stale(eb: leaf); |
4447 | return 0; |
4448 | } |
4449 | /* |
4450 | * delete the item at the leaf level in path. If that empties |
4451 | * the leaf, remove it from the tree |
4452 | */ |
4453 | int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
4454 | struct btrfs_path *path, int slot, int nr) |
4455 | { |
4456 | struct btrfs_fs_info *fs_info = root->fs_info; |
4457 | struct extent_buffer *leaf; |
4458 | int ret = 0; |
4459 | int wret; |
4460 | u32 nritems; |
4461 | |
4462 | leaf = path->nodes[0]; |
4463 | nritems = btrfs_header_nritems(eb: leaf); |
4464 | |
4465 | if (slot + nr != nritems) { |
4466 | const u32 last_off = btrfs_item_offset(eb: leaf, slot: slot + nr - 1); |
4467 | const int data_end = leaf_data_end(leaf); |
4468 | struct btrfs_map_token token; |
4469 | u32 dsize = 0; |
4470 | int i; |
4471 | |
4472 | for (i = 0; i < nr; i++) |
4473 | dsize += btrfs_item_size(eb: leaf, slot: slot + i); |
4474 | |
4475 | memmove_leaf_data(leaf, dst_offset: data_end + dsize, src_offset: data_end, |
4476 | len: last_off - data_end); |
4477 | |
4478 | btrfs_init_map_token(token: &token, eb: leaf); |
4479 | for (i = slot + nr; i < nritems; i++) { |
4480 | u32 ioff; |
4481 | |
4482 | ioff = btrfs_token_item_offset(token: &token, slot: i); |
4483 | btrfs_set_token_item_offset(token: &token, slot: i, val: ioff + dsize); |
4484 | } |
4485 | |
4486 | memmove_leaf_items(leaf, dst_item: slot, src_item: slot + nr, nr_items: nritems - slot - nr); |
4487 | } |
4488 | btrfs_set_header_nritems(eb: leaf, val: nritems - nr); |
4489 | nritems -= nr; |
4490 | |
4491 | /* delete the leaf if we've emptied it */ |
4492 | if (nritems == 0) { |
4493 | if (leaf == root->node) { |
4494 | btrfs_set_header_level(eb: leaf, val: 0); |
4495 | } else { |
4496 | btrfs_clear_buffer_dirty(trans, buf: leaf); |
4497 | ret = btrfs_del_leaf(trans, root, path, leaf); |
4498 | if (ret < 0) |
4499 | return ret; |
4500 | } |
4501 | } else { |
4502 | int used = leaf_space_used(l: leaf, start: 0, nr: nritems); |
4503 | if (slot == 0) { |
4504 | struct btrfs_disk_key disk_key; |
4505 | |
4506 | btrfs_item_key(eb: leaf, disk_key: &disk_key, nr: 0); |
4507 | fixup_low_keys(trans, path, key: &disk_key, level: 1); |
4508 | } |
4509 | |
4510 | /* |
4511 | * Try to delete the leaf if it is mostly empty. We do this by |
4512 | * trying to move all its items into its left and right neighbours. |
4513 | * If we can't move all the items, then we don't delete it - it's |
4514 | * not ideal, but future insertions might fill the leaf with more |
4515 | * items, or items from other leaves might be moved later into our |
4516 | * leaf due to deletions on those leaves. |
4517 | */ |
4518 | if (used < BTRFS_LEAF_DATA_SIZE(info: fs_info) / 3) { |
4519 | u32 min_push_space; |
4520 | |
4521 | /* push_leaf_left fixes the path. |
4522 | * make sure the path still points to our leaf |
4523 | * for possible call to btrfs_del_ptr below |
4524 | */ |
4525 | slot = path->slots[1]; |
4526 | atomic_inc(v: &leaf->refs); |
4527 | /* |
4528 | * We want to be able to at least push one item to the |
4529 | * left neighbour leaf, and that's the first item. |
4530 | */ |
4531 | min_push_space = sizeof(struct btrfs_item) + |
4532 | btrfs_item_size(eb: leaf, slot: 0); |
4533 | wret = push_leaf_left(trans, root, path, min_data_size: 0, |
4534 | data_size: min_push_space, empty: 1, max_slot: (u32)-1); |
4535 | if (wret < 0 && wret != -ENOSPC) |
4536 | ret = wret; |
4537 | |
4538 | if (path->nodes[0] == leaf && |
4539 | btrfs_header_nritems(eb: leaf)) { |
4540 | /* |
4541 | * If we were not able to push all items from our |
4542 | * leaf to its left neighbour, then attempt to |
4543 | * either push all the remaining items to the |
4544 | * right neighbour or none. There's no advantage |
4545 | * in pushing only some items, instead of all, as |
4546 | * it's pointless to end up with a leaf having |
4547 | * too few items while the neighbours can be full |
4548 | * or nearly full. |
4549 | */ |
4550 | nritems = btrfs_header_nritems(eb: leaf); |
4551 | min_push_space = leaf_space_used(l: leaf, start: 0, nr: nritems); |
4552 | wret = push_leaf_right(trans, root, path, min_data_size: 0, |
4553 | data_size: min_push_space, empty: 1, min_slot: 0); |
4554 | if (wret < 0 && wret != -ENOSPC) |
4555 | ret = wret; |
4556 | } |
4557 | |
4558 | if (btrfs_header_nritems(eb: leaf) == 0) { |
4559 | path->slots[1] = slot; |
4560 | ret = btrfs_del_leaf(trans, root, path, leaf); |
4561 | if (ret < 0) |
4562 | return ret; |
4563 | free_extent_buffer(eb: leaf); |
4564 | ret = 0; |
4565 | } else { |
4566 | /* if we're still in the path, make sure |
4567 | * we're dirty. Otherwise, one of the |
4568 | * push_leaf functions must have already |
4569 | * dirtied this buffer |
4570 | */ |
4571 | if (path->nodes[0] == leaf) |
4572 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
4573 | free_extent_buffer(eb: leaf); |
4574 | } |
4575 | } else { |
4576 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
4577 | } |
4578 | } |
4579 | return ret; |
4580 | } |
4581 | |
4582 | /* |
4583 | * A helper function to walk down the tree starting at min_key, and looking |
4584 | * for nodes or leaves that are have a minimum transaction id. |
4585 | * This is used by the btree defrag code, and tree logging |
4586 | * |
4587 | * This does not cow, but it does stuff the starting key it finds back |
4588 | * into min_key, so you can call btrfs_search_slot with cow=1 on the |
4589 | * key and get a writable path. |
4590 | * |
4591 | * This honors path->lowest_level to prevent descent past a given level |
4592 | * of the tree. |
4593 | * |
4594 | * min_trans indicates the oldest transaction that you are interested |
4595 | * in walking through. Any nodes or leaves older than min_trans are |
4596 | * skipped over (without reading them). |
4597 | * |
4598 | * returns zero if something useful was found, < 0 on error and 1 if there |
4599 | * was nothing in the tree that matched the search criteria. |
4600 | */ |
4601 | int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, |
4602 | struct btrfs_path *path, |
4603 | u64 min_trans) |
4604 | { |
4605 | struct extent_buffer *cur; |
4606 | struct btrfs_key found_key; |
4607 | int slot; |
4608 | int sret; |
4609 | u32 nritems; |
4610 | int level; |
4611 | int ret = 1; |
4612 | int keep_locks = path->keep_locks; |
4613 | |
4614 | ASSERT(!path->nowait); |
4615 | path->keep_locks = 1; |
4616 | again: |
4617 | cur = btrfs_read_lock_root_node(root); |
4618 | level = btrfs_header_level(eb: cur); |
4619 | WARN_ON(path->nodes[level]); |
4620 | path->nodes[level] = cur; |
4621 | path->locks[level] = BTRFS_READ_LOCK; |
4622 | |
4623 | if (btrfs_header_generation(eb: cur) < min_trans) { |
4624 | ret = 1; |
4625 | goto out; |
4626 | } |
4627 | while (1) { |
4628 | nritems = btrfs_header_nritems(eb: cur); |
4629 | level = btrfs_header_level(eb: cur); |
4630 | sret = btrfs_bin_search(eb: cur, first_slot: 0, key: min_key, slot: &slot); |
4631 | if (sret < 0) { |
4632 | ret = sret; |
4633 | goto out; |
4634 | } |
4635 | |
4636 | /* at the lowest level, we're done, setup the path and exit */ |
4637 | if (level == path->lowest_level) { |
4638 | if (slot >= nritems) |
4639 | goto find_next_key; |
4640 | ret = 0; |
4641 | path->slots[level] = slot; |
4642 | btrfs_item_key_to_cpu(eb: cur, cpu_key: &found_key, nr: slot); |
4643 | goto out; |
4644 | } |
4645 | if (sret && slot > 0) |
4646 | slot--; |
4647 | /* |
4648 | * check this node pointer against the min_trans parameters. |
4649 | * If it is too old, skip to the next one. |
4650 | */ |
4651 | while (slot < nritems) { |
4652 | u64 gen; |
4653 | |
4654 | gen = btrfs_node_ptr_generation(eb: cur, nr: slot); |
4655 | if (gen < min_trans) { |
4656 | slot++; |
4657 | continue; |
4658 | } |
4659 | break; |
4660 | } |
4661 | find_next_key: |
4662 | /* |
4663 | * we didn't find a candidate key in this node, walk forward |
4664 | * and find another one |
4665 | */ |
4666 | if (slot >= nritems) { |
4667 | path->slots[level] = slot; |
4668 | sret = btrfs_find_next_key(root, path, key: min_key, lowest_level: level, |
4669 | min_trans); |
4670 | if (sret == 0) { |
4671 | btrfs_release_path(p: path); |
4672 | goto again; |
4673 | } else { |
4674 | goto out; |
4675 | } |
4676 | } |
4677 | /* save our key for returning back */ |
4678 | btrfs_node_key_to_cpu(eb: cur, cpu_key: &found_key, nr: slot); |
4679 | path->slots[level] = slot; |
4680 | if (level == path->lowest_level) { |
4681 | ret = 0; |
4682 | goto out; |
4683 | } |
4684 | cur = btrfs_read_node_slot(parent: cur, slot); |
4685 | if (IS_ERR(ptr: cur)) { |
4686 | ret = PTR_ERR(ptr: cur); |
4687 | goto out; |
4688 | } |
4689 | |
4690 | btrfs_tree_read_lock(eb: cur); |
4691 | |
4692 | path->locks[level - 1] = BTRFS_READ_LOCK; |
4693 | path->nodes[level - 1] = cur; |
4694 | unlock_up(path, level, lowest_unlock: 1, min_write_lock_level: 0, NULL); |
4695 | } |
4696 | out: |
4697 | path->keep_locks = keep_locks; |
4698 | if (ret == 0) { |
4699 | btrfs_unlock_up_safe(path, level: path->lowest_level + 1); |
4700 | memcpy(min_key, &found_key, sizeof(found_key)); |
4701 | } |
4702 | return ret; |
4703 | } |
4704 | |
4705 | /* |
4706 | * this is similar to btrfs_next_leaf, but does not try to preserve |
4707 | * and fixup the path. It looks for and returns the next key in the |
4708 | * tree based on the current path and the min_trans parameters. |
4709 | * |
4710 | * 0 is returned if another key is found, < 0 if there are any errors |
4711 | * and 1 is returned if there are no higher keys in the tree |
4712 | * |
4713 | * path->keep_locks should be set to 1 on the search made before |
4714 | * calling this function. |
4715 | */ |
4716 | int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, |
4717 | struct btrfs_key *key, int level, u64 min_trans) |
4718 | { |
4719 | int slot; |
4720 | struct extent_buffer *c; |
4721 | |
4722 | WARN_ON(!path->keep_locks && !path->skip_locking); |
4723 | while (level < BTRFS_MAX_LEVEL) { |
4724 | if (!path->nodes[level]) |
4725 | return 1; |
4726 | |
4727 | slot = path->slots[level] + 1; |
4728 | c = path->nodes[level]; |
4729 | next: |
4730 | if (slot >= btrfs_header_nritems(eb: c)) { |
4731 | int ret; |
4732 | int orig_lowest; |
4733 | struct btrfs_key cur_key; |
4734 | if (level + 1 >= BTRFS_MAX_LEVEL || |
4735 | !path->nodes[level + 1]) |
4736 | return 1; |
4737 | |
4738 | if (path->locks[level + 1] || path->skip_locking) { |
4739 | level++; |
4740 | continue; |
4741 | } |
4742 | |
4743 | slot = btrfs_header_nritems(eb: c) - 1; |
4744 | if (level == 0) |
4745 | btrfs_item_key_to_cpu(eb: c, cpu_key: &cur_key, nr: slot); |
4746 | else |
4747 | btrfs_node_key_to_cpu(eb: c, cpu_key: &cur_key, nr: slot); |
4748 | |
4749 | orig_lowest = path->lowest_level; |
4750 | btrfs_release_path(p: path); |
4751 | path->lowest_level = level; |
4752 | ret = btrfs_search_slot(NULL, root, key: &cur_key, p: path, |
4753 | ins_len: 0, cow: 0); |
4754 | path->lowest_level = orig_lowest; |
4755 | if (ret < 0) |
4756 | return ret; |
4757 | |
4758 | c = path->nodes[level]; |
4759 | slot = path->slots[level]; |
4760 | if (ret == 0) |
4761 | slot++; |
4762 | goto next; |
4763 | } |
4764 | |
4765 | if (level == 0) |
4766 | btrfs_item_key_to_cpu(eb: c, cpu_key: key, nr: slot); |
4767 | else { |
4768 | u64 gen = btrfs_node_ptr_generation(eb: c, nr: slot); |
4769 | |
4770 | if (gen < min_trans) { |
4771 | slot++; |
4772 | goto next; |
4773 | } |
4774 | btrfs_node_key_to_cpu(eb: c, cpu_key: key, nr: slot); |
4775 | } |
4776 | return 0; |
4777 | } |
4778 | return 1; |
4779 | } |
4780 | |
4781 | int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, |
4782 | u64 time_seq) |
4783 | { |
4784 | int slot; |
4785 | int level; |
4786 | struct extent_buffer *c; |
4787 | struct extent_buffer *next; |
4788 | struct btrfs_fs_info *fs_info = root->fs_info; |
4789 | struct btrfs_key key; |
4790 | bool need_commit_sem = false; |
4791 | u32 nritems; |
4792 | int ret; |
4793 | int i; |
4794 | |
4795 | /* |
4796 | * The nowait semantics are used only for write paths, where we don't |
4797 | * use the tree mod log and sequence numbers. |
4798 | */ |
4799 | if (time_seq) |
4800 | ASSERT(!path->nowait); |
4801 | |
4802 | nritems = btrfs_header_nritems(eb: path->nodes[0]); |
4803 | if (nritems == 0) |
4804 | return 1; |
4805 | |
4806 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: nritems - 1); |
4807 | again: |
4808 | level = 1; |
4809 | next = NULL; |
4810 | btrfs_release_path(p: path); |
4811 | |
4812 | path->keep_locks = 1; |
4813 | |
4814 | if (time_seq) { |
4815 | ret = btrfs_search_old_slot(root, key: &key, p: path, time_seq); |
4816 | } else { |
4817 | if (path->need_commit_sem) { |
4818 | path->need_commit_sem = 0; |
4819 | need_commit_sem = true; |
4820 | if (path->nowait) { |
4821 | if (!down_read_trylock(sem: &fs_info->commit_root_sem)) { |
4822 | ret = -EAGAIN; |
4823 | goto done; |
4824 | } |
4825 | } else { |
4826 | down_read(sem: &fs_info->commit_root_sem); |
4827 | } |
4828 | } |
4829 | ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0); |
4830 | } |
4831 | path->keep_locks = 0; |
4832 | |
4833 | if (ret < 0) |
4834 | goto done; |
4835 | |
4836 | nritems = btrfs_header_nritems(eb: path->nodes[0]); |
4837 | /* |
4838 | * by releasing the path above we dropped all our locks. A balance |
4839 | * could have added more items next to the key that used to be |
4840 | * at the very end of the block. So, check again here and |
4841 | * advance the path if there are now more items available. |
4842 | */ |
4843 | if (nritems > 0 && path->slots[0] < nritems - 1) { |
4844 | if (ret == 0) |
4845 | path->slots[0]++; |
4846 | ret = 0; |
4847 | goto done; |
4848 | } |
4849 | /* |
4850 | * So the above check misses one case: |
4851 | * - after releasing the path above, someone has removed the item that |
4852 | * used to be at the very end of the block, and balance between leafs |
4853 | * gets another one with bigger key.offset to replace it. |
4854 | * |
4855 | * This one should be returned as well, or we can get leaf corruption |
4856 | * later(esp. in __btrfs_drop_extents()). |
4857 | * |
4858 | * And a bit more explanation about this check, |
4859 | * with ret > 0, the key isn't found, the path points to the slot |
4860 | * where it should be inserted, so the path->slots[0] item must be the |
4861 | * bigger one. |
4862 | */ |
4863 | if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) { |
4864 | ret = 0; |
4865 | goto done; |
4866 | } |
4867 | |
4868 | while (level < BTRFS_MAX_LEVEL) { |
4869 | if (!path->nodes[level]) { |
4870 | ret = 1; |
4871 | goto done; |
4872 | } |
4873 | |
4874 | slot = path->slots[level] + 1; |
4875 | c = path->nodes[level]; |
4876 | if (slot >= btrfs_header_nritems(eb: c)) { |
4877 | level++; |
4878 | if (level == BTRFS_MAX_LEVEL) { |
4879 | ret = 1; |
4880 | goto done; |
4881 | } |
4882 | continue; |
4883 | } |
4884 | |
4885 | |
4886 | /* |
4887 | * Our current level is where we're going to start from, and to |
4888 | * make sure lockdep doesn't complain we need to drop our locks |
4889 | * and nodes from 0 to our current level. |
4890 | */ |
4891 | for (i = 0; i < level; i++) { |
4892 | if (path->locks[level]) { |
4893 | btrfs_tree_read_unlock(eb: path->nodes[i]); |
4894 | path->locks[i] = 0; |
4895 | } |
4896 | free_extent_buffer(eb: path->nodes[i]); |
4897 | path->nodes[i] = NULL; |
4898 | } |
4899 | |
4900 | next = c; |
4901 | ret = read_block_for_search(root, p: path, eb_ret: &next, level, |
4902 | slot, key: &key); |
4903 | if (ret == -EAGAIN && !path->nowait) |
4904 | goto again; |
4905 | |
4906 | if (ret < 0) { |
4907 | btrfs_release_path(p: path); |
4908 | goto done; |
4909 | } |
4910 | |
4911 | if (!path->skip_locking) { |
4912 | ret = btrfs_try_tree_read_lock(eb: next); |
4913 | if (!ret && path->nowait) { |
4914 | ret = -EAGAIN; |
4915 | goto done; |
4916 | } |
4917 | if (!ret && time_seq) { |
4918 | /* |
4919 | * If we don't get the lock, we may be racing |
4920 | * with push_leaf_left, holding that lock while |
4921 | * itself waiting for the leaf we've currently |
4922 | * locked. To solve this situation, we give up |
4923 | * on our lock and cycle. |
4924 | */ |
4925 | free_extent_buffer(eb: next); |
4926 | btrfs_release_path(p: path); |
4927 | cond_resched(); |
4928 | goto again; |
4929 | } |
4930 | if (!ret) |
4931 | btrfs_tree_read_lock(eb: next); |
4932 | } |
4933 | break; |
4934 | } |
4935 | path->slots[level] = slot; |
4936 | while (1) { |
4937 | level--; |
4938 | path->nodes[level] = next; |
4939 | path->slots[level] = 0; |
4940 | if (!path->skip_locking) |
4941 | path->locks[level] = BTRFS_READ_LOCK; |
4942 | if (!level) |
4943 | break; |
4944 | |
4945 | ret = read_block_for_search(root, p: path, eb_ret: &next, level, |
4946 | slot: 0, key: &key); |
4947 | if (ret == -EAGAIN && !path->nowait) |
4948 | goto again; |
4949 | |
4950 | if (ret < 0) { |
4951 | btrfs_release_path(p: path); |
4952 | goto done; |
4953 | } |
4954 | |
4955 | if (!path->skip_locking) { |
4956 | if (path->nowait) { |
4957 | if (!btrfs_try_tree_read_lock(eb: next)) { |
4958 | ret = -EAGAIN; |
4959 | goto done; |
4960 | } |
4961 | } else { |
4962 | btrfs_tree_read_lock(eb: next); |
4963 | } |
4964 | } |
4965 | } |
4966 | ret = 0; |
4967 | done: |
4968 | unlock_up(path, level: 0, lowest_unlock: 1, min_write_lock_level: 0, NULL); |
4969 | if (need_commit_sem) { |
4970 | int ret2; |
4971 | |
4972 | path->need_commit_sem = 1; |
4973 | ret2 = finish_need_commit_sem_search(path); |
4974 | up_read(sem: &fs_info->commit_root_sem); |
4975 | if (ret2) |
4976 | ret = ret2; |
4977 | } |
4978 | |
4979 | return ret; |
4980 | } |
4981 | |
4982 | int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq) |
4983 | { |
4984 | path->slots[0]++; |
4985 | if (path->slots[0] >= btrfs_header_nritems(eb: path->nodes[0])) |
4986 | return btrfs_next_old_leaf(root, path, time_seq); |
4987 | return 0; |
4988 | } |
4989 | |
4990 | /* |
4991 | * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps |
4992 | * searching until it gets past min_objectid or finds an item of 'type' |
4993 | * |
4994 | * returns 0 if something is found, 1 if nothing was found and < 0 on error |
4995 | */ |
4996 | int btrfs_previous_item(struct btrfs_root *root, |
4997 | struct btrfs_path *path, u64 min_objectid, |
4998 | int type) |
4999 | { |
5000 | struct btrfs_key found_key; |
5001 | struct extent_buffer *leaf; |
5002 | u32 nritems; |
5003 | int ret; |
5004 | |
5005 | while (1) { |
5006 | if (path->slots[0] == 0) { |
5007 | ret = btrfs_prev_leaf(root, path); |
5008 | if (ret != 0) |
5009 | return ret; |
5010 | } else { |
5011 | path->slots[0]--; |
5012 | } |
5013 | leaf = path->nodes[0]; |
5014 | nritems = btrfs_header_nritems(eb: leaf); |
5015 | if (nritems == 0) |
5016 | return 1; |
5017 | if (path->slots[0] == nritems) |
5018 | path->slots[0]--; |
5019 | |
5020 | btrfs_item_key_to_cpu(eb: leaf, cpu_key: &found_key, nr: path->slots[0]); |
5021 | if (found_key.objectid < min_objectid) |
5022 | break; |
5023 | if (found_key.type == type) |
5024 | return 0; |
5025 | if (found_key.objectid == min_objectid && |
5026 | found_key.type < type) |
5027 | break; |
5028 | } |
5029 | return 1; |
5030 | } |
5031 | |
5032 | /* |
5033 | * search in extent tree to find a previous Metadata/Data extent item with |
5034 | * min objecitd. |
5035 | * |
5036 | * returns 0 if something is found, 1 if nothing was found and < 0 on error |
5037 | */ |
5038 | int btrfs_previous_extent_item(struct btrfs_root *root, |
5039 | struct btrfs_path *path, u64 min_objectid) |
5040 | { |
5041 | struct btrfs_key found_key; |
5042 | struct extent_buffer *leaf; |
5043 | u32 nritems; |
5044 | int ret; |
5045 | |
5046 | while (1) { |
5047 | if (path->slots[0] == 0) { |
5048 | ret = btrfs_prev_leaf(root, path); |
5049 | if (ret != 0) |
5050 | return ret; |
5051 | } else { |
5052 | path->slots[0]--; |
5053 | } |
5054 | leaf = path->nodes[0]; |
5055 | nritems = btrfs_header_nritems(eb: leaf); |
5056 | if (nritems == 0) |
5057 | return 1; |
5058 | if (path->slots[0] == nritems) |
5059 | path->slots[0]--; |
5060 | |
5061 | btrfs_item_key_to_cpu(eb: leaf, cpu_key: &found_key, nr: path->slots[0]); |
5062 | if (found_key.objectid < min_objectid) |
5063 | break; |
5064 | if (found_key.type == BTRFS_EXTENT_ITEM_KEY || |
5065 | found_key.type == BTRFS_METADATA_ITEM_KEY) |
5066 | return 0; |
5067 | if (found_key.objectid == min_objectid && |
5068 | found_key.type < BTRFS_EXTENT_ITEM_KEY) |
5069 | break; |
5070 | } |
5071 | return 1; |
5072 | } |
5073 | |
5074 | int __init btrfs_ctree_init(void) |
5075 | { |
5076 | btrfs_path_cachep = kmem_cache_create(name: "btrfs_path" , |
5077 | size: sizeof(struct btrfs_path), align: 0, |
5078 | SLAB_MEM_SPREAD, NULL); |
5079 | if (!btrfs_path_cachep) |
5080 | return -ENOMEM; |
5081 | return 0; |
5082 | } |
5083 | |
5084 | void __cold btrfs_ctree_exit(void) |
5085 | { |
5086 | kmem_cache_destroy(s: btrfs_path_cachep); |
5087 | } |
5088 | |