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1 | /* |
2 | * Copyright (C) 2007,2008 Oracle. All rights reserved. |
3 | * |
4 | * This program is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU General Public |
6 | * License v2 as published by the Free Software Foundation. |
7 | * |
8 | * This program is distributed in the hope that it will be useful, |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
11 | * General Public License for more details. |
12 | * |
13 | * You should have received a copy of the GNU General Public |
14 | * License along with this program; if not, write to the |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
16 | * Boston, MA 021110-1307, USA. |
17 | */ |
18 | |
19 | #include <linux/sched.h> |
20 | #include <linux/slab.h> |
21 | #include "ctree.h" |
22 | #include "disk-io.h" |
23 | #include "transaction.h" |
24 | #include "print-tree.h" |
25 | #include "locking.h" |
26 | |
27 | static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
28 | *root, struct btrfs_path *path, int level); |
29 | static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root |
30 | *root, struct btrfs_key *ins_key, |
31 | struct btrfs_path *path, int data_size, int extend); |
32 | static int push_node_left(struct btrfs_trans_handle *trans, |
33 | struct btrfs_root *root, struct extent_buffer *dst, |
34 | struct extent_buffer *src, int empty); |
35 | static int balance_node_right(struct btrfs_trans_handle *trans, |
36 | struct btrfs_root *root, |
37 | struct extent_buffer *dst_buf, |
38 | struct extent_buffer *src_buf); |
39 | static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
40 | struct btrfs_path *path, int level, int slot); |
41 | static int setup_items_for_insert(struct btrfs_trans_handle *trans, |
42 | struct btrfs_root *root, struct btrfs_path *path, |
43 | struct btrfs_key *cpu_key, u32 *data_size, |
44 | u32 total_data, u32 total_size, int nr); |
45 | |
46 | |
47 | struct btrfs_path *btrfs_alloc_path(void) |
48 | { |
49 | struct btrfs_path *path; |
50 | path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); |
51 | if (path) |
52 | path->reada = 1; |
53 | return path; |
54 | } |
55 | |
56 | /* |
57 | * set all locked nodes in the path to blocking locks. This should |
58 | * be done before scheduling |
59 | */ |
60 | noinline void btrfs_set_path_blocking(struct btrfs_path *p) |
61 | { |
62 | int i; |
63 | for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
64 | if (p->nodes[i] && p->locks[i]) |
65 | btrfs_set_lock_blocking(p->nodes[i]); |
66 | } |
67 | } |
68 | |
69 | /* |
70 | * reset all the locked nodes in the patch to spinning locks. |
71 | * |
72 | * held is used to keep lockdep happy, when lockdep is enabled |
73 | * we set held to a blocking lock before we go around and |
74 | * retake all the spinlocks in the path. You can safely use NULL |
75 | * for held |
76 | */ |
77 | noinline void btrfs_clear_path_blocking(struct btrfs_path *p, |
78 | struct extent_buffer *held) |
79 | { |
80 | int i; |
81 | |
82 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
83 | /* lockdep really cares that we take all of these spinlocks |
84 | * in the right order. If any of the locks in the path are not |
85 | * currently blocking, it is going to complain. So, make really |
86 | * really sure by forcing the path to blocking before we clear |
87 | * the path blocking. |
88 | */ |
89 | if (held) |
90 | btrfs_set_lock_blocking(held); |
91 | btrfs_set_path_blocking(p); |
92 | #endif |
93 | |
94 | for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) { |
95 | if (p->nodes[i] && p->locks[i]) |
96 | btrfs_clear_lock_blocking(p->nodes[i]); |
97 | } |
98 | |
99 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
100 | if (held) |
101 | btrfs_clear_lock_blocking(held); |
102 | #endif |
103 | } |
104 | |
105 | /* this also releases the path */ |
106 | void btrfs_free_path(struct btrfs_path *p) |
107 | { |
108 | btrfs_release_path(NULL, p); |
109 | kmem_cache_free(btrfs_path_cachep, p); |
110 | } |
111 | |
112 | /* |
113 | * path release drops references on the extent buffers in the path |
114 | * and it drops any locks held by this path |
115 | * |
116 | * It is safe to call this on paths that no locks or extent buffers held. |
117 | */ |
118 | noinline void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p) |
119 | { |
120 | int i; |
121 | |
122 | for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
123 | p->slots[i] = 0; |
124 | if (!p->nodes[i]) |
125 | continue; |
126 | if (p->locks[i]) { |
127 | btrfs_tree_unlock(p->nodes[i]); |
128 | p->locks[i] = 0; |
129 | } |
130 | free_extent_buffer(p->nodes[i]); |
131 | p->nodes[i] = NULL; |
132 | } |
133 | } |
134 | |
135 | /* |
136 | * safely gets a reference on the root node of a tree. A lock |
137 | * is not taken, so a concurrent writer may put a different node |
138 | * at the root of the tree. See btrfs_lock_root_node for the |
139 | * looping required. |
140 | * |
141 | * The extent buffer returned by this has a reference taken, so |
142 | * it won't disappear. It may stop being the root of the tree |
143 | * at any time because there are no locks held. |
144 | */ |
145 | struct extent_buffer *btrfs_root_node(struct btrfs_root *root) |
146 | { |
147 | struct extent_buffer *eb; |
148 | spin_lock(&root->node_lock); |
149 | eb = root->node; |
150 | extent_buffer_get(eb); |
151 | spin_unlock(&root->node_lock); |
152 | return eb; |
153 | } |
154 | |
155 | /* loop around taking references on and locking the root node of the |
156 | * tree until you end up with a lock on the root. A locked buffer |
157 | * is returned, with a reference held. |
158 | */ |
159 | struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root) |
160 | { |
161 | struct extent_buffer *eb; |
162 | |
163 | while (1) { |
164 | eb = btrfs_root_node(root); |
165 | btrfs_tree_lock(eb); |
166 | |
167 | spin_lock(&root->node_lock); |
168 | if (eb == root->node) { |
169 | spin_unlock(&root->node_lock); |
170 | break; |
171 | } |
172 | spin_unlock(&root->node_lock); |
173 | |
174 | btrfs_tree_unlock(eb); |
175 | free_extent_buffer(eb); |
176 | } |
177 | return eb; |
178 | } |
179 | |
180 | /* cowonly root (everything not a reference counted cow subvolume), just get |
181 | * put onto a simple dirty list. transaction.c walks this to make sure they |
182 | * get properly updated on disk. |
183 | */ |
184 | static void add_root_to_dirty_list(struct btrfs_root *root) |
185 | { |
186 | if (root->track_dirty && list_empty(&root->dirty_list)) { |
187 | list_add(&root->dirty_list, |
188 | &root->fs_info->dirty_cowonly_roots); |
189 | } |
190 | } |
191 | |
192 | /* |
193 | * used by snapshot creation to make a copy of a root for a tree with |
194 | * a given objectid. The buffer with the new root node is returned in |
195 | * cow_ret, and this func returns zero on success or a negative error code. |
196 | */ |
197 | int btrfs_copy_root(struct btrfs_trans_handle *trans, |
198 | struct btrfs_root *root, |
199 | struct extent_buffer *buf, |
200 | struct extent_buffer **cow_ret, u64 new_root_objectid) |
201 | { |
202 | struct extent_buffer *cow; |
203 | u32 nritems; |
204 | int ret = 0; |
205 | int level; |
206 | struct btrfs_disk_key disk_key; |
207 | |
208 | WARN_ON(root->ref_cows && trans->transid != |
209 | root->fs_info->running_transaction->transid); |
210 | WARN_ON(root->ref_cows && trans->transid != root->last_trans); |
211 | |
212 | level = btrfs_header_level(buf); |
213 | nritems = btrfs_header_nritems(buf); |
214 | if (level == 0) |
215 | btrfs_item_key(buf, &disk_key, 0); |
216 | else |
217 | btrfs_node_key(buf, &disk_key, 0); |
218 | |
219 | cow = btrfs_alloc_free_block(trans, root, buf->len, 0, |
220 | new_root_objectid, &disk_key, level, |
221 | buf->start, 0); |
222 | if (IS_ERR(cow)) |
223 | return PTR_ERR(cow); |
224 | |
225 | copy_extent_buffer(cow, buf, 0, 0, cow->len); |
226 | btrfs_set_header_bytenr(cow, cow->start); |
227 | btrfs_set_header_generation(cow, trans->transid); |
228 | btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
229 | btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
230 | BTRFS_HEADER_FLAG_RELOC); |
231 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
232 | btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
233 | else |
234 | btrfs_set_header_owner(cow, new_root_objectid); |
235 | |
236 | write_extent_buffer(cow, root->fs_info->fsid, |
237 | (unsigned long)btrfs_header_fsid(cow), |
238 | BTRFS_FSID_SIZE); |
239 | |
240 | WARN_ON(btrfs_header_generation(buf) > trans->transid); |
241 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
242 | ret = btrfs_inc_ref(trans, root, cow, 1); |
243 | else |
244 | ret = btrfs_inc_ref(trans, root, cow, 0); |
245 | |
246 | if (ret) |
247 | return ret; |
248 | |
249 | btrfs_mark_buffer_dirty(cow); |
250 | *cow_ret = cow; |
251 | return 0; |
252 | } |
253 | |
254 | /* |
255 | * check if the tree block can be shared by multiple trees |
256 | */ |
257 | int btrfs_block_can_be_shared(struct btrfs_root *root, |
258 | struct extent_buffer *buf) |
259 | { |
260 | /* |
261 | * Tree blocks not in refernece counted trees and tree roots |
262 | * are never shared. If a block was allocated after the last |
263 | * snapshot and the block was not allocated by tree relocation, |
264 | * we know the block is not shared. |
265 | */ |
266 | if (root->ref_cows && |
267 | buf != root->node && buf != root->commit_root && |
268 | (btrfs_header_generation(buf) <= |
269 | btrfs_root_last_snapshot(&root->root_item) || |
270 | btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) |
271 | return 1; |
272 | #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 |
273 | if (root->ref_cows && |
274 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
275 | return 1; |
276 | #endif |
277 | return 0; |
278 | } |
279 | |
280 | static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, |
281 | struct btrfs_root *root, |
282 | struct extent_buffer *buf, |
283 | struct extent_buffer *cow) |
284 | { |
285 | u64 refs; |
286 | u64 owner; |
287 | u64 flags; |
288 | u64 new_flags = 0; |
289 | int ret; |
290 | |
291 | /* |
292 | * Backrefs update rules: |
293 | * |
294 | * Always use full backrefs for extent pointers in tree block |
295 | * allocated by tree relocation. |
296 | * |
297 | * If a shared tree block is no longer referenced by its owner |
298 | * tree (btrfs_header_owner(buf) == root->root_key.objectid), |
299 | * use full backrefs for extent pointers in tree block. |
300 | * |
301 | * If a tree block is been relocating |
302 | * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), |
303 | * use full backrefs for extent pointers in tree block. |
304 | * The reason for this is some operations (such as drop tree) |
305 | * are only allowed for blocks use full backrefs. |
306 | */ |
307 | |
308 | if (btrfs_block_can_be_shared(root, buf)) { |
309 | ret = btrfs_lookup_extent_info(trans, root, buf->start, |
310 | buf->len, &refs, &flags); |
311 | BUG_ON(ret); |
312 | BUG_ON(refs == 0); |
313 | } else { |
314 | refs = 1; |
315 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
316 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
317 | flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; |
318 | else |
319 | flags = 0; |
320 | } |
321 | |
322 | owner = btrfs_header_owner(buf); |
323 | BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && |
324 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); |
325 | |
326 | if (refs > 1) { |
327 | if ((owner == root->root_key.objectid || |
328 | root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && |
329 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
330 | ret = btrfs_inc_ref(trans, root, buf, 1); |
331 | BUG_ON(ret); |
332 | |
333 | if (root->root_key.objectid == |
334 | BTRFS_TREE_RELOC_OBJECTID) { |
335 | ret = btrfs_dec_ref(trans, root, buf, 0); |
336 | BUG_ON(ret); |
337 | ret = btrfs_inc_ref(trans, root, cow, 1); |
338 | BUG_ON(ret); |
339 | } |
340 | new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; |
341 | } else { |
342 | |
343 | if (root->root_key.objectid == |
344 | BTRFS_TREE_RELOC_OBJECTID) |
345 | ret = btrfs_inc_ref(trans, root, cow, 1); |
346 | else |
347 | ret = btrfs_inc_ref(trans, root, cow, 0); |
348 | BUG_ON(ret); |
349 | } |
350 | if (new_flags != 0) { |
351 | ret = btrfs_set_disk_extent_flags(trans, root, |
352 | buf->start, |
353 | buf->len, |
354 | new_flags, 0); |
355 | BUG_ON(ret); |
356 | } |
357 | } else { |
358 | if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { |
359 | if (root->root_key.objectid == |
360 | BTRFS_TREE_RELOC_OBJECTID) |
361 | ret = btrfs_inc_ref(trans, root, cow, 1); |
362 | else |
363 | ret = btrfs_inc_ref(trans, root, cow, 0); |
364 | BUG_ON(ret); |
365 | ret = btrfs_dec_ref(trans, root, buf, 1); |
366 | BUG_ON(ret); |
367 | } |
368 | clean_tree_block(trans, root, buf); |
369 | } |
370 | return 0; |
371 | } |
372 | |
373 | /* |
374 | * does the dirty work in cow of a single block. The parent block (if |
375 | * supplied) is updated to point to the new cow copy. The new buffer is marked |
376 | * dirty and returned locked. If you modify the block it needs to be marked |
377 | * dirty again. |
378 | * |
379 | * search_start -- an allocation hint for the new block |
380 | * |
381 | * empty_size -- a hint that you plan on doing more cow. This is the size in |
382 | * bytes the allocator should try to find free next to the block it returns. |
383 | * This is just a hint and may be ignored by the allocator. |
384 | */ |
385 | static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, |
386 | struct btrfs_root *root, |
387 | struct extent_buffer *buf, |
388 | struct extent_buffer *parent, int parent_slot, |
389 | struct extent_buffer **cow_ret, |
390 | u64 search_start, u64 empty_size) |
391 | { |
392 | struct btrfs_disk_key disk_key; |
393 | struct extent_buffer *cow; |
394 | int level; |
395 | int unlock_orig = 0; |
396 | u64 parent_start; |
397 | |
398 | if (*cow_ret == buf) |
399 | unlock_orig = 1; |
400 | |
401 | btrfs_assert_tree_locked(buf); |
402 | |
403 | WARN_ON(root->ref_cows && trans->transid != |
404 | root->fs_info->running_transaction->transid); |
405 | WARN_ON(root->ref_cows && trans->transid != root->last_trans); |
406 | |
407 | level = btrfs_header_level(buf); |
408 | |
409 | if (level == 0) |
410 | btrfs_item_key(buf, &disk_key, 0); |
411 | else |
412 | btrfs_node_key(buf, &disk_key, 0); |
413 | |
414 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { |
415 | if (parent) |
416 | parent_start = parent->start; |
417 | else |
418 | parent_start = 0; |
419 | } else |
420 | parent_start = 0; |
421 | |
422 | cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start, |
423 | root->root_key.objectid, &disk_key, |
424 | level, search_start, empty_size); |
425 | if (IS_ERR(cow)) |
426 | return PTR_ERR(cow); |
427 | |
428 | /* cow is set to blocking by btrfs_init_new_buffer */ |
429 | |
430 | copy_extent_buffer(cow, buf, 0, 0, cow->len); |
431 | btrfs_set_header_bytenr(cow, cow->start); |
432 | btrfs_set_header_generation(cow, trans->transid); |
433 | btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
434 | btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
435 | BTRFS_HEADER_FLAG_RELOC); |
436 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
437 | btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
438 | else |
439 | btrfs_set_header_owner(cow, root->root_key.objectid); |
440 | |
441 | write_extent_buffer(cow, root->fs_info->fsid, |
442 | (unsigned long)btrfs_header_fsid(cow), |
443 | BTRFS_FSID_SIZE); |
444 | |
445 | update_ref_for_cow(trans, root, buf, cow); |
446 | |
447 | if (buf == root->node) { |
448 | WARN_ON(parent && parent != buf); |
449 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
450 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
451 | parent_start = buf->start; |
452 | else |
453 | parent_start = 0; |
454 | |
455 | spin_lock(&root->node_lock); |
456 | root->node = cow; |
457 | extent_buffer_get(cow); |
458 | spin_unlock(&root->node_lock); |
459 | |
460 | btrfs_free_tree_block(trans, root, buf->start, buf->len, |
461 | parent_start, root->root_key.objectid, level); |
462 | free_extent_buffer(buf); |
463 | add_root_to_dirty_list(root); |
464 | } else { |
465 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
466 | parent_start = parent->start; |
467 | else |
468 | parent_start = 0; |
469 | |
470 | WARN_ON(trans->transid != btrfs_header_generation(parent)); |
471 | btrfs_set_node_blockptr(parent, parent_slot, |
472 | cow->start); |
473 | btrfs_set_node_ptr_generation(parent, parent_slot, |
474 | trans->transid); |
475 | btrfs_mark_buffer_dirty(parent); |
476 | btrfs_free_tree_block(trans, root, buf->start, buf->len, |
477 | parent_start, root->root_key.objectid, level); |
478 | } |
479 | if (unlock_orig) |
480 | btrfs_tree_unlock(buf); |
481 | free_extent_buffer(buf); |
482 | btrfs_mark_buffer_dirty(cow); |
483 | *cow_ret = cow; |
484 | return 0; |
485 | } |
486 | |
487 | static inline int should_cow_block(struct btrfs_trans_handle *trans, |
488 | struct btrfs_root *root, |
489 | struct extent_buffer *buf) |
490 | { |
491 | if (btrfs_header_generation(buf) == trans->transid && |
492 | !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && |
493 | !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && |
494 | btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) |
495 | return 0; |
496 | return 1; |
497 | } |
498 | |
499 | /* |
500 | * cows a single block, see __btrfs_cow_block for the real work. |
501 | * This version of it has extra checks so that a block isn't cow'd more than |
502 | * once per transaction, as long as it hasn't been written yet |
503 | */ |
504 | noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, |
505 | struct btrfs_root *root, struct extent_buffer *buf, |
506 | struct extent_buffer *parent, int parent_slot, |
507 | struct extent_buffer **cow_ret) |
508 | { |
509 | u64 search_start; |
510 | int ret; |
511 | |
512 | if (trans->transaction != root->fs_info->running_transaction) { |
513 | printk(KERN_CRIT "trans %llu running %llu\n", |
514 | (unsigned long long)trans->transid, |
515 | (unsigned long long) |
516 | root->fs_info->running_transaction->transid); |
517 | WARN_ON(1); |
518 | } |
519 | if (trans->transid != root->fs_info->generation) { |
520 | printk(KERN_CRIT "trans %llu running %llu\n", |
521 | (unsigned long long)trans->transid, |
522 | (unsigned long long)root->fs_info->generation); |
523 | WARN_ON(1); |
524 | } |
525 | |
526 | if (!should_cow_block(trans, root, buf)) { |
527 | *cow_ret = buf; |
528 | return 0; |
529 | } |
530 | |
531 | search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1); |
532 | |
533 | if (parent) |
534 | btrfs_set_lock_blocking(parent); |
535 | btrfs_set_lock_blocking(buf); |
536 | |
537 | ret = __btrfs_cow_block(trans, root, buf, parent, |
538 | parent_slot, cow_ret, search_start, 0); |
539 | return ret; |
540 | } |
541 | |
542 | /* |
543 | * helper function for defrag to decide if two blocks pointed to by a |
544 | * node are actually close by |
545 | */ |
546 | static int close_blocks(u64 blocknr, u64 other, u32 blocksize) |
547 | { |
548 | if (blocknr < other && other - (blocknr + blocksize) < 32768) |
549 | return 1; |
550 | if (blocknr > other && blocknr - (other + blocksize) < 32768) |
551 | return 1; |
552 | return 0; |
553 | } |
554 | |
555 | /* |
556 | * compare two keys in a memcmp fashion |
557 | */ |
558 | static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2) |
559 | { |
560 | struct btrfs_key k1; |
561 | |
562 | btrfs_disk_key_to_cpu(&k1, disk); |
563 | |
564 | return btrfs_comp_cpu_keys(&k1, k2); |
565 | } |
566 | |
567 | /* |
568 | * same as comp_keys only with two btrfs_key's |
569 | */ |
570 | int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2) |
571 | { |
572 | if (k1->objectid > k2->objectid) |
573 | return 1; |
574 | if (k1->objectid < k2->objectid) |
575 | return -1; |
576 | if (k1->type > k2->type) |
577 | return 1; |
578 | if (k1->type < k2->type) |
579 | return -1; |
580 | if (k1->offset > k2->offset) |
581 | return 1; |
582 | if (k1->offset < k2->offset) |
583 | return -1; |
584 | return 0; |
585 | } |
586 | |
587 | /* |
588 | * this is used by the defrag code to go through all the |
589 | * leaves pointed to by a node and reallocate them so that |
590 | * disk order is close to key order |
591 | */ |
592 | int btrfs_realloc_node(struct btrfs_trans_handle *trans, |
593 | struct btrfs_root *root, struct extent_buffer *parent, |
594 | int start_slot, int cache_only, u64 *last_ret, |
595 | struct btrfs_key *progress) |
596 | { |
597 | struct extent_buffer *cur; |
598 | u64 blocknr; |
599 | u64 gen; |
600 | u64 search_start = *last_ret; |
601 | u64 last_block = 0; |
602 | u64 other; |
603 | u32 parent_nritems; |
604 | int end_slot; |
605 | int i; |
606 | int err = 0; |
607 | int parent_level; |
608 | int uptodate; |
609 | u32 blocksize; |
610 | int progress_passed = 0; |
611 | struct btrfs_disk_key disk_key; |
612 | |
613 | parent_level = btrfs_header_level(parent); |
614 | if (cache_only && parent_level != 1) |
615 | return 0; |
616 | |
617 | if (trans->transaction != root->fs_info->running_transaction) |
618 | WARN_ON(1); |
619 | if (trans->transid != root->fs_info->generation) |
620 | WARN_ON(1); |
621 | |
622 | parent_nritems = btrfs_header_nritems(parent); |
623 | blocksize = btrfs_level_size(root, parent_level - 1); |
624 | end_slot = parent_nritems; |
625 | |
626 | if (parent_nritems == 1) |
627 | return 0; |
628 | |
629 | btrfs_set_lock_blocking(parent); |
630 | |
631 | for (i = start_slot; i < end_slot; i++) { |
632 | int close = 1; |
633 | |
634 | if (!parent->map_token) { |
635 | map_extent_buffer(parent, |
636 | btrfs_node_key_ptr_offset(i), |
637 | sizeof(struct btrfs_key_ptr), |
638 | &parent->map_token, &parent->kaddr, |
639 | &parent->map_start, &parent->map_len, |
640 | KM_USER1); |
641 | } |
642 | btrfs_node_key(parent, &disk_key, i); |
643 | if (!progress_passed && comp_keys(&disk_key, progress) < 0) |
644 | continue; |
645 | |
646 | progress_passed = 1; |
647 | blocknr = btrfs_node_blockptr(parent, i); |
648 | gen = btrfs_node_ptr_generation(parent, i); |
649 | if (last_block == 0) |
650 | last_block = blocknr; |
651 | |
652 | if (i > 0) { |
653 | other = btrfs_node_blockptr(parent, i - 1); |
654 | close = close_blocks(blocknr, other, blocksize); |
655 | } |
656 | if (!close && i < end_slot - 2) { |
657 | other = btrfs_node_blockptr(parent, i + 1); |
658 | close = close_blocks(blocknr, other, blocksize); |
659 | } |
660 | if (close) { |
661 | last_block = blocknr; |
662 | continue; |
663 | } |
664 | if (parent->map_token) { |
665 | unmap_extent_buffer(parent, parent->map_token, |
666 | KM_USER1); |
667 | parent->map_token = NULL; |
668 | } |
669 | |
670 | cur = btrfs_find_tree_block(root, blocknr, blocksize); |
671 | if (cur) |
672 | uptodate = btrfs_buffer_uptodate(cur, gen); |
673 | else |
674 | uptodate = 0; |
675 | if (!cur || !uptodate) { |
676 | if (cache_only) { |
677 | free_extent_buffer(cur); |
678 | continue; |
679 | } |
680 | if (!cur) { |
681 | cur = read_tree_block(root, blocknr, |
682 | blocksize, gen); |
683 | } else if (!uptodate) { |
684 | btrfs_read_buffer(cur, gen); |
685 | } |
686 | } |
687 | if (search_start == 0) |
688 | search_start = last_block; |
689 | |
690 | btrfs_tree_lock(cur); |
691 | btrfs_set_lock_blocking(cur); |
692 | err = __btrfs_cow_block(trans, root, cur, parent, i, |
693 | &cur, search_start, |
694 | min(16 * blocksize, |
695 | (end_slot - i) * blocksize)); |
696 | if (err) { |
697 | btrfs_tree_unlock(cur); |
698 | free_extent_buffer(cur); |
699 | break; |
700 | } |
701 | search_start = cur->start; |
702 | last_block = cur->start; |
703 | *last_ret = search_start; |
704 | btrfs_tree_unlock(cur); |
705 | free_extent_buffer(cur); |
706 | } |
707 | if (parent->map_token) { |
708 | unmap_extent_buffer(parent, parent->map_token, |
709 | KM_USER1); |
710 | parent->map_token = NULL; |
711 | } |
712 | return err; |
713 | } |
714 | |
715 | /* |
716 | * The leaf data grows from end-to-front in the node. |
717 | * this returns the address of the start of the last item, |
718 | * which is the stop of the leaf data stack |
719 | */ |
720 | static inline unsigned int leaf_data_end(struct btrfs_root *root, |
721 | struct extent_buffer *leaf) |
722 | { |
723 | u32 nr = btrfs_header_nritems(leaf); |
724 | if (nr == 0) |
725 | return BTRFS_LEAF_DATA_SIZE(root); |
726 | return btrfs_item_offset_nr(leaf, nr - 1); |
727 | } |
728 | |
729 | /* |
730 | * extra debugging checks to make sure all the items in a key are |
731 | * well formed and in the proper order |
732 | */ |
733 | static int check_node(struct btrfs_root *root, struct btrfs_path *path, |
734 | int level) |
735 | { |
736 | struct extent_buffer *parent = NULL; |
737 | struct extent_buffer *node = path->nodes[level]; |
738 | struct btrfs_disk_key parent_key; |
739 | struct btrfs_disk_key node_key; |
740 | int parent_slot; |
741 | int slot; |
742 | struct btrfs_key cpukey; |
743 | u32 nritems = btrfs_header_nritems(node); |
744 | |
745 | if (path->nodes[level + 1]) |
746 | parent = path->nodes[level + 1]; |
747 | |
748 | slot = path->slots[level]; |
749 | BUG_ON(nritems == 0); |
750 | if (parent) { |
751 | parent_slot = path->slots[level + 1]; |
752 | btrfs_node_key(parent, &parent_key, parent_slot); |
753 | btrfs_node_key(node, &node_key, 0); |
754 | BUG_ON(memcmp(&parent_key, &node_key, |
755 | sizeof(struct btrfs_disk_key))); |
756 | BUG_ON(btrfs_node_blockptr(parent, parent_slot) != |
757 | btrfs_header_bytenr(node)); |
758 | } |
759 | BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root)); |
760 | if (slot != 0) { |
761 | btrfs_node_key_to_cpu(node, &cpukey, slot - 1); |
762 | btrfs_node_key(node, &node_key, slot); |
763 | BUG_ON(comp_keys(&node_key, &cpukey) <= 0); |
764 | } |
765 | if (slot < nritems - 1) { |
766 | btrfs_node_key_to_cpu(node, &cpukey, slot + 1); |
767 | btrfs_node_key(node, &node_key, slot); |
768 | BUG_ON(comp_keys(&node_key, &cpukey) >= 0); |
769 | } |
770 | return 0; |
771 | } |
772 | |
773 | /* |
774 | * extra checking to make sure all the items in a leaf are |
775 | * well formed and in the proper order |
776 | */ |
777 | static int check_leaf(struct btrfs_root *root, struct btrfs_path *path, |
778 | int level) |
779 | { |
780 | struct extent_buffer *leaf = path->nodes[level]; |
781 | struct extent_buffer *parent = NULL; |
782 | int parent_slot; |
783 | struct btrfs_key cpukey; |
784 | struct btrfs_disk_key parent_key; |
785 | struct btrfs_disk_key leaf_key; |
786 | int slot = path->slots[0]; |
787 | |
788 | u32 nritems = btrfs_header_nritems(leaf); |
789 | |
790 | if (path->nodes[level + 1]) |
791 | parent = path->nodes[level + 1]; |
792 | |
793 | if (nritems == 0) |
794 | return 0; |
795 | |
796 | if (parent) { |
797 | parent_slot = path->slots[level + 1]; |
798 | btrfs_node_key(parent, &parent_key, parent_slot); |
799 | btrfs_item_key(leaf, &leaf_key, 0); |
800 | |
801 | BUG_ON(memcmp(&parent_key, &leaf_key, |
802 | sizeof(struct btrfs_disk_key))); |
803 | BUG_ON(btrfs_node_blockptr(parent, parent_slot) != |
804 | btrfs_header_bytenr(leaf)); |
805 | } |
806 | if (slot != 0 && slot < nritems - 1) { |
807 | btrfs_item_key(leaf, &leaf_key, slot); |
808 | btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1); |
809 | if (comp_keys(&leaf_key, &cpukey) <= 0) { |
810 | btrfs_print_leaf(root, leaf); |
811 | printk(KERN_CRIT "slot %d offset bad key\n", slot); |
812 | BUG_ON(1); |
813 | } |
814 | if (btrfs_item_offset_nr(leaf, slot - 1) != |
815 | btrfs_item_end_nr(leaf, slot)) { |
816 | btrfs_print_leaf(root, leaf); |
817 | printk(KERN_CRIT "slot %d offset bad\n", slot); |
818 | BUG_ON(1); |
819 | } |
820 | } |
821 | if (slot < nritems - 1) { |
822 | btrfs_item_key(leaf, &leaf_key, slot); |
823 | btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1); |
824 | BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0); |
825 | if (btrfs_item_offset_nr(leaf, slot) != |
826 | btrfs_item_end_nr(leaf, slot + 1)) { |
827 | btrfs_print_leaf(root, leaf); |
828 | printk(KERN_CRIT "slot %d offset bad\n", slot); |
829 | BUG_ON(1); |
830 | } |
831 | } |
832 | BUG_ON(btrfs_item_offset_nr(leaf, 0) + |
833 | btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root)); |
834 | return 0; |
835 | } |
836 | |
837 | static noinline int check_block(struct btrfs_root *root, |
838 | struct btrfs_path *path, int level) |
839 | { |
840 | return 0; |
841 | if (level == 0) |
842 | return check_leaf(root, path, level); |
843 | return check_node(root, path, level); |
844 | } |
845 | |
846 | /* |
847 | * search for key in the extent_buffer. The items start at offset p, |
848 | * and they are item_size apart. There are 'max' items in p. |
849 | * |
850 | * the slot in the array is returned via slot, and it points to |
851 | * the place where you would insert key if it is not found in |
852 | * the array. |
853 | * |
854 | * slot may point to max if the key is bigger than all of the keys |
855 | */ |
856 | static noinline int generic_bin_search(struct extent_buffer *eb, |
857 | unsigned long p, |
858 | int item_size, struct btrfs_key *key, |
859 | int max, int *slot) |
860 | { |
861 | int low = 0; |
862 | int high = max; |
863 | int mid; |
864 | int ret; |
865 | struct btrfs_disk_key *tmp = NULL; |
866 | struct btrfs_disk_key unaligned; |
867 | unsigned long offset; |
868 | char *map_token = NULL; |
869 | char *kaddr = NULL; |
870 | unsigned long map_start = 0; |
871 | unsigned long map_len = 0; |
872 | int err; |
873 | |
874 | while (low < high) { |
875 | mid = (low + high) / 2; |
876 | offset = p + mid * item_size; |
877 | |
878 | if (!map_token || offset < map_start || |
879 | (offset + sizeof(struct btrfs_disk_key)) > |
880 | map_start + map_len) { |
881 | if (map_token) { |
882 | unmap_extent_buffer(eb, map_token, KM_USER0); |
883 | map_token = NULL; |
884 | } |
885 | |
886 | err = map_private_extent_buffer(eb, offset, |
887 | sizeof(struct btrfs_disk_key), |
888 | &map_token, &kaddr, |
889 | &map_start, &map_len, KM_USER0); |
890 | |
891 | if (!err) { |
892 | tmp = (struct btrfs_disk_key *)(kaddr + offset - |
893 | map_start); |
894 | } else { |
895 | read_extent_buffer(eb, &unaligned, |
896 | offset, sizeof(unaligned)); |
897 | tmp = &unaligned; |
898 | } |
899 | |
900 | } else { |
901 | tmp = (struct btrfs_disk_key *)(kaddr + offset - |
902 | map_start); |
903 | } |
904 | ret = comp_keys(tmp, key); |
905 | |
906 | if (ret < 0) |
907 | low = mid + 1; |
908 | else if (ret > 0) |
909 | high = mid; |
910 | else { |
911 | *slot = mid; |
912 | if (map_token) |
913 | unmap_extent_buffer(eb, map_token, KM_USER0); |
914 | return 0; |
915 | } |
916 | } |
917 | *slot = low; |
918 | if (map_token) |
919 | unmap_extent_buffer(eb, map_token, KM_USER0); |
920 | return 1; |
921 | } |
922 | |
923 | /* |
924 | * simple bin_search frontend that does the right thing for |
925 | * leaves vs nodes |
926 | */ |
927 | static int bin_search(struct extent_buffer *eb, struct btrfs_key *key, |
928 | int level, int *slot) |
929 | { |
930 | if (level == 0) { |
931 | return generic_bin_search(eb, |
932 | offsetof(struct btrfs_leaf, items), |
933 | sizeof(struct btrfs_item), |
934 | key, btrfs_header_nritems(eb), |
935 | slot); |
936 | } else { |
937 | return generic_bin_search(eb, |
938 | offsetof(struct btrfs_node, ptrs), |
939 | sizeof(struct btrfs_key_ptr), |
940 | key, btrfs_header_nritems(eb), |
941 | slot); |
942 | } |
943 | return -1; |
944 | } |
945 | |
946 | int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key, |
947 | int level, int *slot) |
948 | { |
949 | return bin_search(eb, key, level, slot); |
950 | } |
951 | |
952 | /* given a node and slot number, this reads the blocks it points to. The |
953 | * extent buffer is returned with a reference taken (but unlocked). |
954 | * NULL is returned on error. |
955 | */ |
956 | static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root, |
957 | struct extent_buffer *parent, int slot) |
958 | { |
959 | int level = btrfs_header_level(parent); |
960 | if (slot < 0) |
961 | return NULL; |
962 | if (slot >= btrfs_header_nritems(parent)) |
963 | return NULL; |
964 | |
965 | BUG_ON(level == 0); |
966 | |
967 | return read_tree_block(root, btrfs_node_blockptr(parent, slot), |
968 | btrfs_level_size(root, level - 1), |
969 | btrfs_node_ptr_generation(parent, slot)); |
970 | } |
971 | |
972 | /* |
973 | * node level balancing, used to make sure nodes are in proper order for |
974 | * item deletion. We balance from the top down, so we have to make sure |
975 | * that a deletion won't leave an node completely empty later on. |
976 | */ |
977 | static noinline int balance_level(struct btrfs_trans_handle *trans, |
978 | struct btrfs_root *root, |
979 | struct btrfs_path *path, int level) |
980 | { |
981 | struct extent_buffer *right = NULL; |
982 | struct extent_buffer *mid; |
983 | struct extent_buffer *left = NULL; |
984 | struct extent_buffer *parent = NULL; |
985 | int ret = 0; |
986 | int wret; |
987 | int pslot; |
988 | int orig_slot = path->slots[level]; |
989 | int err_on_enospc = 0; |
990 | u64 orig_ptr; |
991 | |
992 | if (level == 0) |
993 | return 0; |
994 | |
995 | mid = path->nodes[level]; |
996 | |
997 | WARN_ON(!path->locks[level]); |
998 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
999 | |
1000 | orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
1001 | |
1002 | if (level < BTRFS_MAX_LEVEL - 1) |
1003 | parent = path->nodes[level + 1]; |
1004 | pslot = path->slots[level + 1]; |
1005 | |
1006 | /* |
1007 | * deal with the case where there is only one pointer in the root |
1008 | * by promoting the node below to a root |
1009 | */ |
1010 | if (!parent) { |
1011 | struct extent_buffer *child; |
1012 | |
1013 | if (btrfs_header_nritems(mid) != 1) |
1014 | return 0; |
1015 | |
1016 | /* promote the child to a root */ |
1017 | child = read_node_slot(root, mid, 0); |
1018 | BUG_ON(!child); |
1019 | btrfs_tree_lock(child); |
1020 | btrfs_set_lock_blocking(child); |
1021 | ret = btrfs_cow_block(trans, root, child, mid, 0, &child); |
1022 | BUG_ON(ret); |
1023 | |
1024 | spin_lock(&root->node_lock); |
1025 | root->node = child; |
1026 | spin_unlock(&root->node_lock); |
1027 | |
1028 | add_root_to_dirty_list(root); |
1029 | btrfs_tree_unlock(child); |
1030 | |
1031 | path->locks[level] = 0; |
1032 | path->nodes[level] = NULL; |
1033 | clean_tree_block(trans, root, mid); |
1034 | btrfs_tree_unlock(mid); |
1035 | /* once for the path */ |
1036 | free_extent_buffer(mid); |
1037 | ret = btrfs_free_tree_block(trans, root, mid->start, mid->len, |
1038 | 0, root->root_key.objectid, level); |
1039 | /* once for the root ptr */ |
1040 | free_extent_buffer(mid); |
1041 | return ret; |
1042 | } |
1043 | if (btrfs_header_nritems(mid) > |
1044 | BTRFS_NODEPTRS_PER_BLOCK(root) / 4) |
1045 | return 0; |
1046 | |
1047 | if (btrfs_header_nritems(mid) < 2) |
1048 | err_on_enospc = 1; |
1049 | |
1050 | left = read_node_slot(root, parent, pslot - 1); |
1051 | if (left) { |
1052 | btrfs_tree_lock(left); |
1053 | btrfs_set_lock_blocking(left); |
1054 | wret = btrfs_cow_block(trans, root, left, |
1055 | parent, pslot - 1, &left); |
1056 | if (wret) { |
1057 | ret = wret; |
1058 | goto enospc; |
1059 | } |
1060 | } |
1061 | right = read_node_slot(root, parent, pslot + 1); |
1062 | if (right) { |
1063 | btrfs_tree_lock(right); |
1064 | btrfs_set_lock_blocking(right); |
1065 | wret = btrfs_cow_block(trans, root, right, |
1066 | parent, pslot + 1, &right); |
1067 | if (wret) { |
1068 | ret = wret; |
1069 | goto enospc; |
1070 | } |
1071 | } |
1072 | |
1073 | /* first, try to make some room in the middle buffer */ |
1074 | if (left) { |
1075 | orig_slot += btrfs_header_nritems(left); |
1076 | wret = push_node_left(trans, root, left, mid, 1); |
1077 | if (wret < 0) |
1078 | ret = wret; |
1079 | if (btrfs_header_nritems(mid) < 2) |
1080 | err_on_enospc = 1; |
1081 | } |
1082 | |
1083 | /* |
1084 | * then try to empty the right most buffer into the middle |
1085 | */ |
1086 | if (right) { |
1087 | wret = push_node_left(trans, root, mid, right, 1); |
1088 | if (wret < 0 && wret != -ENOSPC) |
1089 | ret = wret; |
1090 | if (btrfs_header_nritems(right) == 0) { |
1091 | u64 bytenr = right->start; |
1092 | u32 blocksize = right->len; |
1093 | |
1094 | clean_tree_block(trans, root, right); |
1095 | btrfs_tree_unlock(right); |
1096 | free_extent_buffer(right); |
1097 | right = NULL; |
1098 | wret = del_ptr(trans, root, path, level + 1, pslot + |
1099 | 1); |
1100 | if (wret) |
1101 | ret = wret; |
1102 | wret = btrfs_free_tree_block(trans, root, |
1103 | bytenr, blocksize, 0, |
1104 | root->root_key.objectid, |
1105 | level); |
1106 | if (wret) |
1107 | ret = wret; |
1108 | } else { |
1109 | struct btrfs_disk_key right_key; |
1110 | btrfs_node_key(right, &right_key, 0); |
1111 | btrfs_set_node_key(parent, &right_key, pslot + 1); |
1112 | btrfs_mark_buffer_dirty(parent); |
1113 | } |
1114 | } |
1115 | if (btrfs_header_nritems(mid) == 1) { |
1116 | /* |
1117 | * we're not allowed to leave a node with one item in the |
1118 | * tree during a delete. A deletion from lower in the tree |
1119 | * could try to delete the only pointer in this node. |
1120 | * So, pull some keys from the left. |
1121 | * There has to be a left pointer at this point because |
1122 | * otherwise we would have pulled some pointers from the |
1123 | * right |
1124 | */ |
1125 | BUG_ON(!left); |
1126 | wret = balance_node_right(trans, root, mid, left); |
1127 | if (wret < 0) { |
1128 | ret = wret; |
1129 | goto enospc; |
1130 | } |
1131 | if (wret == 1) { |
1132 | wret = push_node_left(trans, root, left, mid, 1); |
1133 | if (wret < 0) |
1134 | ret = wret; |
1135 | } |
1136 | BUG_ON(wret == 1); |
1137 | } |
1138 | if (btrfs_header_nritems(mid) == 0) { |
1139 | /* we've managed to empty the middle node, drop it */ |
1140 | u64 bytenr = mid->start; |
1141 | u32 blocksize = mid->len; |
1142 | |
1143 | clean_tree_block(trans, root, mid); |
1144 | btrfs_tree_unlock(mid); |
1145 | free_extent_buffer(mid); |
1146 | mid = NULL; |
1147 | wret = del_ptr(trans, root, path, level + 1, pslot); |
1148 | if (wret) |
1149 | ret = wret; |
1150 | wret = btrfs_free_tree_block(trans, root, bytenr, blocksize, |
1151 | 0, root->root_key.objectid, level); |
1152 | if (wret) |
1153 | ret = wret; |
1154 | } else { |
1155 | /* update the parent key to reflect our changes */ |
1156 | struct btrfs_disk_key mid_key; |
1157 | btrfs_node_key(mid, &mid_key, 0); |
1158 | btrfs_set_node_key(parent, &mid_key, pslot); |
1159 | btrfs_mark_buffer_dirty(parent); |
1160 | } |
1161 | |
1162 | /* update the path */ |
1163 | if (left) { |
1164 | if (btrfs_header_nritems(left) > orig_slot) { |
1165 | extent_buffer_get(left); |
1166 | /* left was locked after cow */ |
1167 | path->nodes[level] = left; |
1168 | path->slots[level + 1] -= 1; |
1169 | path->slots[level] = orig_slot; |
1170 | if (mid) { |
1171 | btrfs_tree_unlock(mid); |
1172 | free_extent_buffer(mid); |
1173 | } |
1174 | } else { |
1175 | orig_slot -= btrfs_header_nritems(left); |
1176 | path->slots[level] = orig_slot; |
1177 | } |
1178 | } |
1179 | /* double check we haven't messed things up */ |
1180 | check_block(root, path, level); |
1181 | if (orig_ptr != |
1182 | btrfs_node_blockptr(path->nodes[level], path->slots[level])) |
1183 | BUG(); |
1184 | enospc: |
1185 | if (right) { |
1186 | btrfs_tree_unlock(right); |
1187 | free_extent_buffer(right); |
1188 | } |
1189 | if (left) { |
1190 | if (path->nodes[level] != left) |
1191 | btrfs_tree_unlock(left); |
1192 | free_extent_buffer(left); |
1193 | } |
1194 | return ret; |
1195 | } |
1196 | |
1197 | /* Node balancing for insertion. Here we only split or push nodes around |
1198 | * when they are completely full. This is also done top down, so we |
1199 | * have to be pessimistic. |
1200 | */ |
1201 | static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, |
1202 | struct btrfs_root *root, |
1203 | struct btrfs_path *path, int level) |
1204 | { |
1205 | struct extent_buffer *right = NULL; |
1206 | struct extent_buffer *mid; |
1207 | struct extent_buffer *left = NULL; |
1208 | struct extent_buffer *parent = NULL; |
1209 | int ret = 0; |
1210 | int wret; |
1211 | int pslot; |
1212 | int orig_slot = path->slots[level]; |
1213 | u64 orig_ptr; |
1214 | |
1215 | if (level == 0) |
1216 | return 1; |
1217 | |
1218 | mid = path->nodes[level]; |
1219 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
1220 | orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
1221 | |
1222 | if (level < BTRFS_MAX_LEVEL - 1) |
1223 | parent = path->nodes[level + 1]; |
1224 | pslot = path->slots[level + 1]; |
1225 | |
1226 | if (!parent) |
1227 | return 1; |
1228 | |
1229 | left = read_node_slot(root, parent, pslot - 1); |
1230 | |
1231 | /* first, try to make some room in the middle buffer */ |
1232 | if (left) { |
1233 | u32 left_nr; |
1234 | |
1235 | btrfs_tree_lock(left); |
1236 | btrfs_set_lock_blocking(left); |
1237 | |
1238 | left_nr = btrfs_header_nritems(left); |
1239 | if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { |
1240 | wret = 1; |
1241 | } else { |
1242 | ret = btrfs_cow_block(trans, root, left, parent, |
1243 | pslot - 1, &left); |
1244 | if (ret) |
1245 | wret = 1; |
1246 | else { |
1247 | wret = push_node_left(trans, root, |
1248 | left, mid, 0); |
1249 | } |
1250 | } |
1251 | if (wret < 0) |
1252 | ret = wret; |
1253 | if (wret == 0) { |
1254 | struct btrfs_disk_key disk_key; |
1255 | orig_slot += left_nr; |
1256 | btrfs_node_key(mid, &disk_key, 0); |
1257 | btrfs_set_node_key(parent, &disk_key, pslot); |
1258 | btrfs_mark_buffer_dirty(parent); |
1259 | if (btrfs_header_nritems(left) > orig_slot) { |
1260 | path->nodes[level] = left; |
1261 | path->slots[level + 1] -= 1; |
1262 | path->slots[level] = orig_slot; |
1263 | btrfs_tree_unlock(mid); |
1264 | free_extent_buffer(mid); |
1265 | } else { |
1266 | orig_slot -= |
1267 | btrfs_header_nritems(left); |
1268 | path->slots[level] = orig_slot; |
1269 | btrfs_tree_unlock(left); |
1270 | free_extent_buffer(left); |
1271 | } |
1272 | return 0; |
1273 | } |
1274 | btrfs_tree_unlock(left); |
1275 | free_extent_buffer(left); |
1276 | } |
1277 | right = read_node_slot(root, parent, pslot + 1); |
1278 | |
1279 | /* |
1280 | * then try to empty the right most buffer into the middle |
1281 | */ |
1282 | if (right) { |
1283 | u32 right_nr; |
1284 | |
1285 | btrfs_tree_lock(right); |
1286 | btrfs_set_lock_blocking(right); |
1287 | |
1288 | right_nr = btrfs_header_nritems(right); |
1289 | if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { |
1290 | wret = 1; |
1291 | } else { |
1292 | ret = btrfs_cow_block(trans, root, right, |
1293 | parent, pslot + 1, |
1294 | &right); |
1295 | if (ret) |
1296 | wret = 1; |
1297 | else { |
1298 | wret = balance_node_right(trans, root, |
1299 | right, mid); |
1300 | } |
1301 | } |
1302 | if (wret < 0) |
1303 | ret = wret; |
1304 | if (wret == 0) { |
1305 | struct btrfs_disk_key disk_key; |
1306 | |
1307 | btrfs_node_key(right, &disk_key, 0); |
1308 | btrfs_set_node_key(parent, &disk_key, pslot + 1); |
1309 | btrfs_mark_buffer_dirty(parent); |
1310 | |
1311 | if (btrfs_header_nritems(mid) <= orig_slot) { |
1312 | path->nodes[level] = right; |
1313 | path->slots[level + 1] += 1; |
1314 | path->slots[level] = orig_slot - |
1315 | btrfs_header_nritems(mid); |
1316 | btrfs_tree_unlock(mid); |
1317 | free_extent_buffer(mid); |
1318 | } else { |
1319 | btrfs_tree_unlock(right); |
1320 | free_extent_buffer(right); |
1321 | } |
1322 | return 0; |
1323 | } |
1324 | btrfs_tree_unlock(right); |
1325 | free_extent_buffer(right); |
1326 | } |
1327 | return 1; |
1328 | } |
1329 | |
1330 | /* |
1331 | * readahead one full node of leaves, finding things that are close |
1332 | * to the block in 'slot', and triggering ra on them. |
1333 | */ |
1334 | static void reada_for_search(struct btrfs_root *root, |
1335 | struct btrfs_path *path, |
1336 | int level, int slot, u64 objectid) |
1337 | { |
1338 | struct extent_buffer *node; |
1339 | struct btrfs_disk_key disk_key; |
1340 | u32 nritems; |
1341 | u64 search; |
1342 | u64 target; |
1343 | u64 nread = 0; |
1344 | int direction = path->reada; |
1345 | struct extent_buffer *eb; |
1346 | u32 nr; |
1347 | u32 blocksize; |
1348 | u32 nscan = 0; |
1349 | |
1350 | if (level != 1) |
1351 | return; |
1352 | |
1353 | if (!path->nodes[level]) |
1354 | return; |
1355 | |
1356 | node = path->nodes[level]; |
1357 | |
1358 | search = btrfs_node_blockptr(node, slot); |
1359 | blocksize = btrfs_level_size(root, level - 1); |
1360 | eb = btrfs_find_tree_block(root, search, blocksize); |
1361 | if (eb) { |
1362 | free_extent_buffer(eb); |
1363 | return; |
1364 | } |
1365 | |
1366 | target = search; |
1367 | |
1368 | nritems = btrfs_header_nritems(node); |
1369 | nr = slot; |
1370 | while (1) { |
1371 | if (direction < 0) { |
1372 | if (nr == 0) |
1373 | break; |
1374 | nr--; |
1375 | } else if (direction > 0) { |
1376 | nr++; |
1377 | if (nr >= nritems) |
1378 | break; |
1379 | } |
1380 | if (path->reada < 0 && objectid) { |
1381 | btrfs_node_key(node, &disk_key, nr); |
1382 | if (btrfs_disk_key_objectid(&disk_key) != objectid) |
1383 | break; |
1384 | } |
1385 | search = btrfs_node_blockptr(node, nr); |
1386 | if ((search <= target && target - search <= 65536) || |
1387 | (search > target && search - target <= 65536)) { |
1388 | readahead_tree_block(root, search, blocksize, |
1389 | btrfs_node_ptr_generation(node, nr)); |
1390 | nread += blocksize; |
1391 | } |
1392 | nscan++; |
1393 | if ((nread > 65536 || nscan > 32)) |
1394 | break; |
1395 | } |
1396 | } |
1397 | |
1398 | /* |
1399 | * returns -EAGAIN if it had to drop the path, or zero if everything was in |
1400 | * cache |
1401 | */ |
1402 | static noinline int reada_for_balance(struct btrfs_root *root, |
1403 | struct btrfs_path *path, int level) |
1404 | { |
1405 | int slot; |
1406 | int nritems; |
1407 | struct extent_buffer *parent; |
1408 | struct extent_buffer *eb; |
1409 | u64 gen; |
1410 | u64 block1 = 0; |
1411 | u64 block2 = 0; |
1412 | int ret = 0; |
1413 | int blocksize; |
1414 | |
1415 | parent = path->nodes[level + 1]; |
1416 | if (!parent) |
1417 | return 0; |
1418 | |
1419 | nritems = btrfs_header_nritems(parent); |
1420 | slot = path->slots[level + 1]; |
1421 | blocksize = btrfs_level_size(root, level); |
1422 | |
1423 | if (slot > 0) { |
1424 | block1 = btrfs_node_blockptr(parent, slot - 1); |
1425 | gen = btrfs_node_ptr_generation(parent, slot - 1); |
1426 | eb = btrfs_find_tree_block(root, block1, blocksize); |
1427 | if (eb && btrfs_buffer_uptodate(eb, gen)) |
1428 | block1 = 0; |
1429 | free_extent_buffer(eb); |
1430 | } |
1431 | if (slot + 1 < nritems) { |
1432 | block2 = btrfs_node_blockptr(parent, slot + 1); |
1433 | gen = btrfs_node_ptr_generation(parent, slot + 1); |
1434 | eb = btrfs_find_tree_block(root, block2, blocksize); |
1435 | if (eb && btrfs_buffer_uptodate(eb, gen)) |
1436 | block2 = 0; |
1437 | free_extent_buffer(eb); |
1438 | } |
1439 | if (block1 || block2) { |
1440 | ret = -EAGAIN; |
1441 | |
1442 | /* release the whole path */ |
1443 | btrfs_release_path(root, path); |
1444 | |
1445 | /* read the blocks */ |
1446 | if (block1) |
1447 | readahead_tree_block(root, block1, blocksize, 0); |
1448 | if (block2) |
1449 | readahead_tree_block(root, block2, blocksize, 0); |
1450 | |
1451 | if (block1) { |
1452 | eb = read_tree_block(root, block1, blocksize, 0); |
1453 | free_extent_buffer(eb); |
1454 | } |
1455 | if (block2) { |
1456 | eb = read_tree_block(root, block2, blocksize, 0); |
1457 | free_extent_buffer(eb); |
1458 | } |
1459 | } |
1460 | return ret; |
1461 | } |
1462 | |
1463 | |
1464 | /* |
1465 | * when we walk down the tree, it is usually safe to unlock the higher layers |
1466 | * in the tree. The exceptions are when our path goes through slot 0, because |
1467 | * operations on the tree might require changing key pointers higher up in the |
1468 | * tree. |
1469 | * |
1470 | * callers might also have set path->keep_locks, which tells this code to keep |
1471 | * the lock if the path points to the last slot in the block. This is part of |
1472 | * walking through the tree, and selecting the next slot in the higher block. |
1473 | * |
1474 | * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so |
1475 | * if lowest_unlock is 1, level 0 won't be unlocked |
1476 | */ |
1477 | static noinline void unlock_up(struct btrfs_path *path, int level, |
1478 | int lowest_unlock) |
1479 | { |
1480 | int i; |
1481 | int skip_level = level; |
1482 | int no_skips = 0; |
1483 | struct extent_buffer *t; |
1484 | |
1485 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
1486 | if (!path->nodes[i]) |
1487 | break; |
1488 | if (!path->locks[i]) |
1489 | break; |
1490 | if (!no_skips && path->slots[i] == 0) { |
1491 | skip_level = i + 1; |
1492 | continue; |
1493 | } |
1494 | if (!no_skips && path->keep_locks) { |
1495 | u32 nritems; |
1496 | t = path->nodes[i]; |
1497 | nritems = btrfs_header_nritems(t); |
1498 | if (nritems < 1 || path->slots[i] >= nritems - 1) { |
1499 | skip_level = i + 1; |
1500 | continue; |
1501 | } |
1502 | } |
1503 | if (skip_level < i && i >= lowest_unlock) |
1504 | no_skips = 1; |
1505 | |
1506 | t = path->nodes[i]; |
1507 | if (i >= lowest_unlock && i > skip_level && path->locks[i]) { |
1508 | btrfs_tree_unlock(t); |
1509 | path->locks[i] = 0; |
1510 | } |
1511 | } |
1512 | } |
1513 | |
1514 | /* |
1515 | * This releases any locks held in the path starting at level and |
1516 | * going all the way up to the root. |
1517 | * |
1518 | * btrfs_search_slot will keep the lock held on higher nodes in a few |
1519 | * corner cases, such as COW of the block at slot zero in the node. This |
1520 | * ignores those rules, and it should only be called when there are no |
1521 | * more updates to be done higher up in the tree. |
1522 | */ |
1523 | noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level) |
1524 | { |
1525 | int i; |
1526 | |
1527 | if (path->keep_locks) |
1528 | return; |
1529 | |
1530 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
1531 | if (!path->nodes[i]) |
1532 | continue; |
1533 | if (!path->locks[i]) |
1534 | continue; |
1535 | btrfs_tree_unlock(path->nodes[i]); |
1536 | path->locks[i] = 0; |
1537 | } |
1538 | } |
1539 | |
1540 | /* |
1541 | * helper function for btrfs_search_slot. The goal is to find a block |
1542 | * in cache without setting the path to blocking. If we find the block |
1543 | * we return zero and the path is unchanged. |
1544 | * |
1545 | * If we can't find the block, we set the path blocking and do some |
1546 | * reada. -EAGAIN is returned and the search must be repeated. |
1547 | */ |
1548 | static int |
1549 | read_block_for_search(struct btrfs_trans_handle *trans, |
1550 | struct btrfs_root *root, struct btrfs_path *p, |
1551 | struct extent_buffer **eb_ret, int level, int slot, |
1552 | struct btrfs_key *key) |
1553 | { |
1554 | u64 blocknr; |
1555 | u64 gen; |
1556 | u32 blocksize; |
1557 | struct extent_buffer *b = *eb_ret; |
1558 | struct extent_buffer *tmp; |
1559 | int ret; |
1560 | |
1561 | blocknr = btrfs_node_blockptr(b, slot); |
1562 | gen = btrfs_node_ptr_generation(b, slot); |
1563 | blocksize = btrfs_level_size(root, level - 1); |
1564 | |
1565 | tmp = btrfs_find_tree_block(root, blocknr, blocksize); |
1566 | if (tmp && btrfs_buffer_uptodate(tmp, gen)) { |
1567 | /* |
1568 | * we found an up to date block without sleeping, return |
1569 | * right away |
1570 | */ |
1571 | *eb_ret = tmp; |
1572 | return 0; |
1573 | } |
1574 | |
1575 | /* |
1576 | * reduce lock contention at high levels |
1577 | * of the btree by dropping locks before |
1578 | * we read. Don't release the lock on the current |
1579 | * level because we need to walk this node to figure |
1580 | * out which blocks to read. |
1581 | */ |
1582 | btrfs_unlock_up_safe(p, level + 1); |
1583 | btrfs_set_path_blocking(p); |
1584 | |
1585 | if (tmp) |
1586 | free_extent_buffer(tmp); |
1587 | if (p->reada) |
1588 | reada_for_search(root, p, level, slot, key->objectid); |
1589 | |
1590 | btrfs_release_path(NULL, p); |
1591 | |
1592 | ret = -EAGAIN; |
1593 | tmp = read_tree_block(root, blocknr, blocksize, gen); |
1594 | if (tmp) { |
1595 | /* |
1596 | * If the read above didn't mark this buffer up to date, |
1597 | * it will never end up being up to date. Set ret to EIO now |
1598 | * and give up so that our caller doesn't loop forever |
1599 | * on our EAGAINs. |
1600 | */ |
1601 | if (!btrfs_buffer_uptodate(tmp, 0)) |
1602 | ret = -EIO; |
1603 | free_extent_buffer(tmp); |
1604 | } |
1605 | return ret; |
1606 | } |
1607 | |
1608 | /* |
1609 | * helper function for btrfs_search_slot. This does all of the checks |
1610 | * for node-level blocks and does any balancing required based on |
1611 | * the ins_len. |
1612 | * |
1613 | * If no extra work was required, zero is returned. If we had to |
1614 | * drop the path, -EAGAIN is returned and btrfs_search_slot must |
1615 | * start over |
1616 | */ |
1617 | static int |
1618 | setup_nodes_for_search(struct btrfs_trans_handle *trans, |
1619 | struct btrfs_root *root, struct btrfs_path *p, |
1620 | struct extent_buffer *b, int level, int ins_len) |
1621 | { |
1622 | int ret; |
1623 | if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= |
1624 | BTRFS_NODEPTRS_PER_BLOCK(root) - 3) { |
1625 | int sret; |
1626 | |
1627 | sret = reada_for_balance(root, p, level); |
1628 | if (sret) |
1629 | goto again; |
1630 | |
1631 | btrfs_set_path_blocking(p); |
1632 | sret = split_node(trans, root, p, level); |
1633 | btrfs_clear_path_blocking(p, NULL); |
1634 | |
1635 | BUG_ON(sret > 0); |
1636 | if (sret) { |
1637 | ret = sret; |
1638 | goto done; |
1639 | } |
1640 | b = p->nodes[level]; |
1641 | } else if (ins_len < 0 && btrfs_header_nritems(b) < |
1642 | BTRFS_NODEPTRS_PER_BLOCK(root) / 2) { |
1643 | int sret; |
1644 | |
1645 | sret = reada_for_balance(root, p, level); |
1646 | if (sret) |
1647 | goto again; |
1648 | |
1649 | btrfs_set_path_blocking(p); |
1650 | sret = balance_level(trans, root, p, level); |
1651 | btrfs_clear_path_blocking(p, NULL); |
1652 | |
1653 | if (sret) { |
1654 | ret = sret; |
1655 | goto done; |
1656 | } |
1657 | b = p->nodes[level]; |
1658 | if (!b) { |
1659 | btrfs_release_path(NULL, p); |
1660 | goto again; |
1661 | } |
1662 | BUG_ON(btrfs_header_nritems(b) == 1); |
1663 | } |
1664 | return 0; |
1665 | |
1666 | again: |
1667 | ret = -EAGAIN; |
1668 | done: |
1669 | return ret; |
1670 | } |
1671 | |
1672 | /* |
1673 | * look for key in the tree. path is filled in with nodes along the way |
1674 | * if key is found, we return zero and you can find the item in the leaf |
1675 | * level of the path (level 0) |
1676 | * |
1677 | * If the key isn't found, the path points to the slot where it should |
1678 | * be inserted, and 1 is returned. If there are other errors during the |
1679 | * search a negative error number is returned. |
1680 | * |
1681 | * if ins_len > 0, nodes and leaves will be split as we walk down the |
1682 | * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if |
1683 | * possible) |
1684 | */ |
1685 | int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root |
1686 | *root, struct btrfs_key *key, struct btrfs_path *p, int |
1687 | ins_len, int cow) |
1688 | { |
1689 | struct extent_buffer *b; |
1690 | int slot; |
1691 | int ret; |
1692 | int err; |
1693 | int level; |
1694 | int lowest_unlock = 1; |
1695 | u8 lowest_level = 0; |
1696 | |
1697 | lowest_level = p->lowest_level; |
1698 | WARN_ON(lowest_level && ins_len > 0); |
1699 | WARN_ON(p->nodes[0] != NULL); |
1700 | |
1701 | if (ins_len < 0) |
1702 | lowest_unlock = 2; |
1703 | |
1704 | again: |
1705 | if (p->search_commit_root) { |
1706 | b = root->commit_root; |
1707 | extent_buffer_get(b); |
1708 | if (!p->skip_locking) |
1709 | btrfs_tree_lock(b); |
1710 | } else { |
1711 | if (p->skip_locking) |
1712 | b = btrfs_root_node(root); |
1713 | else |
1714 | b = btrfs_lock_root_node(root); |
1715 | } |
1716 | |
1717 | while (b) { |
1718 | level = btrfs_header_level(b); |
1719 | |
1720 | /* |
1721 | * setup the path here so we can release it under lock |
1722 | * contention with the cow code |
1723 | */ |
1724 | p->nodes[level] = b; |
1725 | if (!p->skip_locking) |
1726 | p->locks[level] = 1; |
1727 | |
1728 | if (cow) { |
1729 | /* |
1730 | * if we don't really need to cow this block |
1731 | * then we don't want to set the path blocking, |
1732 | * so we test it here |
1733 | */ |
1734 | if (!should_cow_block(trans, root, b)) |
1735 | goto cow_done; |
1736 | |
1737 | btrfs_set_path_blocking(p); |
1738 | |
1739 | err = btrfs_cow_block(trans, root, b, |
1740 | p->nodes[level + 1], |
1741 | p->slots[level + 1], &b); |
1742 | if (err) { |
1743 | free_extent_buffer(b); |
1744 | ret = err; |
1745 | goto done; |
1746 | } |
1747 | } |
1748 | cow_done: |
1749 | BUG_ON(!cow && ins_len); |
1750 | if (level != btrfs_header_level(b)) |
1751 | WARN_ON(1); |
1752 | level = btrfs_header_level(b); |
1753 | |
1754 | p->nodes[level] = b; |
1755 | if (!p->skip_locking) |
1756 | p->locks[level] = 1; |
1757 | |
1758 | btrfs_clear_path_blocking(p, NULL); |
1759 | |
1760 | /* |
1761 | * we have a lock on b and as long as we aren't changing |
1762 | * the tree, there is no way to for the items in b to change. |
1763 | * It is safe to drop the lock on our parent before we |
1764 | * go through the expensive btree search on b. |
1765 | * |
1766 | * If cow is true, then we might be changing slot zero, |
1767 | * which may require changing the parent. So, we can't |
1768 | * drop the lock until after we know which slot we're |
1769 | * operating on. |
1770 | */ |
1771 | if (!cow) |
1772 | btrfs_unlock_up_safe(p, level + 1); |
1773 | |
1774 | ret = check_block(root, p, level); |
1775 | if (ret) { |
1776 | ret = -1; |
1777 | goto done; |
1778 | } |
1779 | |
1780 | ret = bin_search(b, key, level, &slot); |
1781 | |
1782 | if (level != 0) { |
1783 | int dec = 0; |
1784 | if (ret && slot > 0) { |
1785 | dec = 1; |
1786 | slot -= 1; |
1787 | } |
1788 | p->slots[level] = slot; |
1789 | err = setup_nodes_for_search(trans, root, p, b, level, |
1790 | ins_len); |
1791 | if (err == -EAGAIN) |
1792 | goto again; |
1793 | if (err) { |
1794 | ret = err; |
1795 | goto done; |
1796 | } |
1797 | b = p->nodes[level]; |
1798 | slot = p->slots[level]; |
1799 | |
1800 | unlock_up(p, level, lowest_unlock); |
1801 | |
1802 | if (level == lowest_level) { |
1803 | if (dec) |
1804 | p->slots[level]++; |
1805 | goto done; |
1806 | } |
1807 | |
1808 | err = read_block_for_search(trans, root, p, |
1809 | &b, level, slot, key); |
1810 | if (err == -EAGAIN) |
1811 | goto again; |
1812 | if (err) { |
1813 | ret = err; |
1814 | goto done; |
1815 | } |
1816 | |
1817 | if (!p->skip_locking) { |
1818 | btrfs_clear_path_blocking(p, NULL); |
1819 | err = btrfs_try_spin_lock(b); |
1820 | |
1821 | if (!err) { |
1822 | btrfs_set_path_blocking(p); |
1823 | btrfs_tree_lock(b); |
1824 | btrfs_clear_path_blocking(p, b); |
1825 | } |
1826 | } |
1827 | } else { |
1828 | p->slots[level] = slot; |
1829 | if (ins_len > 0 && |
1830 | btrfs_leaf_free_space(root, b) < ins_len) { |
1831 | btrfs_set_path_blocking(p); |
1832 | err = split_leaf(trans, root, key, |
1833 | p, ins_len, ret == 0); |
1834 | btrfs_clear_path_blocking(p, NULL); |
1835 | |
1836 | BUG_ON(err > 0); |
1837 | if (err) { |
1838 | ret = err; |
1839 | goto done; |
1840 | } |
1841 | } |
1842 | if (!p->search_for_split) |
1843 | unlock_up(p, level, lowest_unlock); |
1844 | goto done; |
1845 | } |
1846 | } |
1847 | ret = 1; |
1848 | done: |
1849 | /* |
1850 | * we don't really know what they plan on doing with the path |
1851 | * from here on, so for now just mark it as blocking |
1852 | */ |
1853 | if (!p->leave_spinning) |
1854 | btrfs_set_path_blocking(p); |
1855 | if (ret < 0) |
1856 | btrfs_release_path(root, p); |
1857 | return ret; |
1858 | } |
1859 | |
1860 | /* |
1861 | * adjust the pointers going up the tree, starting at level |
1862 | * making sure the right key of each node is points to 'key'. |
1863 | * This is used after shifting pointers to the left, so it stops |
1864 | * fixing up pointers when a given leaf/node is not in slot 0 of the |
1865 | * higher levels |
1866 | * |
1867 | * If this fails to write a tree block, it returns -1, but continues |
1868 | * fixing up the blocks in ram so the tree is consistent. |
1869 | */ |
1870 | static int fixup_low_keys(struct btrfs_trans_handle *trans, |
1871 | struct btrfs_root *root, struct btrfs_path *path, |
1872 | struct btrfs_disk_key *key, int level) |
1873 | { |
1874 | int i; |
1875 | int ret = 0; |
1876 | struct extent_buffer *t; |
1877 | |
1878 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
1879 | int tslot = path->slots[i]; |
1880 | if (!path->nodes[i]) |
1881 | break; |
1882 | t = path->nodes[i]; |
1883 | btrfs_set_node_key(t, key, tslot); |
1884 | btrfs_mark_buffer_dirty(path->nodes[i]); |
1885 | if (tslot != 0) |
1886 | break; |
1887 | } |
1888 | return ret; |
1889 | } |
1890 | |
1891 | /* |
1892 | * update item key. |
1893 | * |
1894 | * This function isn't completely safe. It's the caller's responsibility |
1895 | * that the new key won't break the order |
1896 | */ |
1897 | int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, |
1898 | struct btrfs_root *root, struct btrfs_path *path, |
1899 | struct btrfs_key *new_key) |
1900 | { |
1901 | struct btrfs_disk_key disk_key; |
1902 | struct extent_buffer *eb; |
1903 | int slot; |
1904 | |
1905 | eb = path->nodes[0]; |
1906 | slot = path->slots[0]; |
1907 | if (slot > 0) { |
1908 | btrfs_item_key(eb, &disk_key, slot - 1); |
1909 | if (comp_keys(&disk_key, new_key) >= 0) |
1910 | return -1; |
1911 | } |
1912 | if (slot < btrfs_header_nritems(eb) - 1) { |
1913 | btrfs_item_key(eb, &disk_key, slot + 1); |
1914 | if (comp_keys(&disk_key, new_key) <= 0) |
1915 | return -1; |
1916 | } |
1917 | |
1918 | btrfs_cpu_key_to_disk(&disk_key, new_key); |
1919 | btrfs_set_item_key(eb, &disk_key, slot); |
1920 | btrfs_mark_buffer_dirty(eb); |
1921 | if (slot == 0) |
1922 | fixup_low_keys(trans, root, path, &disk_key, 1); |
1923 | return 0; |
1924 | } |
1925 | |
1926 | /* |
1927 | * try to push data from one node into the next node left in the |
1928 | * tree. |
1929 | * |
1930 | * returns 0 if some ptrs were pushed left, < 0 if there was some horrible |
1931 | * error, and > 0 if there was no room in the left hand block. |
1932 | */ |
1933 | static int push_node_left(struct btrfs_trans_handle *trans, |
1934 | struct btrfs_root *root, struct extent_buffer *dst, |
1935 | struct extent_buffer *src, int empty) |
1936 | { |
1937 | int push_items = 0; |
1938 | int src_nritems; |
1939 | int dst_nritems; |
1940 | int ret = 0; |
1941 | |
1942 | src_nritems = btrfs_header_nritems(src); |
1943 | dst_nritems = btrfs_header_nritems(dst); |
1944 | push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems; |
1945 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
1946 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
1947 | |
1948 | if (!empty && src_nritems <= 8) |
1949 | return 1; |
1950 | |
1951 | if (push_items <= 0) |
1952 | return 1; |
1953 | |
1954 | if (empty) { |
1955 | push_items = min(src_nritems, push_items); |
1956 | if (push_items < src_nritems) { |
1957 | /* leave at least 8 pointers in the node if |
1958 | * we aren't going to empty it |
1959 | */ |
1960 | if (src_nritems - push_items < 8) { |
1961 | if (push_items <= 8) |
1962 | return 1; |
1963 | push_items -= 8; |
1964 | } |
1965 | } |
1966 | } else |
1967 | push_items = min(src_nritems - 8, push_items); |
1968 | |
1969 | copy_extent_buffer(dst, src, |
1970 | btrfs_node_key_ptr_offset(dst_nritems), |
1971 | btrfs_node_key_ptr_offset(0), |
1972 | push_items * sizeof(struct btrfs_key_ptr)); |
1973 | |
1974 | if (push_items < src_nritems) { |
1975 | memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0), |
1976 | btrfs_node_key_ptr_offset(push_items), |
1977 | (src_nritems - push_items) * |
1978 | sizeof(struct btrfs_key_ptr)); |
1979 | } |
1980 | btrfs_set_header_nritems(src, src_nritems - push_items); |
1981 | btrfs_set_header_nritems(dst, dst_nritems + push_items); |
1982 | btrfs_mark_buffer_dirty(src); |
1983 | btrfs_mark_buffer_dirty(dst); |
1984 | |
1985 | return ret; |
1986 | } |
1987 | |
1988 | /* |
1989 | * try to push data from one node into the next node right in the |
1990 | * tree. |
1991 | * |
1992 | * returns 0 if some ptrs were pushed, < 0 if there was some horrible |
1993 | * error, and > 0 if there was no room in the right hand block. |
1994 | * |
1995 | * this will only push up to 1/2 the contents of the left node over |
1996 | */ |
1997 | static int balance_node_right(struct btrfs_trans_handle *trans, |
1998 | struct btrfs_root *root, |
1999 | struct extent_buffer *dst, |
2000 | struct extent_buffer *src) |
2001 | { |
2002 | int push_items = 0; |
2003 | int max_push; |
2004 | int src_nritems; |
2005 | int dst_nritems; |
2006 | int ret = 0; |
2007 | |
2008 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
2009 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
2010 | |
2011 | src_nritems = btrfs_header_nritems(src); |
2012 | dst_nritems = btrfs_header_nritems(dst); |
2013 | push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems; |
2014 | if (push_items <= 0) |
2015 | return 1; |
2016 | |
2017 | if (src_nritems < 4) |
2018 | return 1; |
2019 | |
2020 | max_push = src_nritems / 2 + 1; |
2021 | /* don't try to empty the node */ |
2022 | if (max_push >= src_nritems) |
2023 | return 1; |
2024 | |
2025 | if (max_push < push_items) |
2026 | push_items = max_push; |
2027 | |
2028 | memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items), |
2029 | btrfs_node_key_ptr_offset(0), |
2030 | (dst_nritems) * |
2031 | sizeof(struct btrfs_key_ptr)); |
2032 | |
2033 | copy_extent_buffer(dst, src, |
2034 | btrfs_node_key_ptr_offset(0), |
2035 | btrfs_node_key_ptr_offset(src_nritems - push_items), |
2036 | push_items * sizeof(struct btrfs_key_ptr)); |
2037 | |
2038 | btrfs_set_header_nritems(src, src_nritems - push_items); |
2039 | btrfs_set_header_nritems(dst, dst_nritems + push_items); |
2040 | |
2041 | btrfs_mark_buffer_dirty(src); |
2042 | btrfs_mark_buffer_dirty(dst); |
2043 | |
2044 | return ret; |
2045 | } |
2046 | |
2047 | /* |
2048 | * helper function to insert a new root level in the tree. |
2049 | * A new node is allocated, and a single item is inserted to |
2050 | * point to the existing root |
2051 | * |
2052 | * returns zero on success or < 0 on failure. |
2053 | */ |
2054 | static noinline int insert_new_root(struct btrfs_trans_handle *trans, |
2055 | struct btrfs_root *root, |
2056 | struct btrfs_path *path, int level) |
2057 | { |
2058 | u64 lower_gen; |
2059 | struct extent_buffer *lower; |
2060 | struct extent_buffer *c; |
2061 | struct extent_buffer *old; |
2062 | struct btrfs_disk_key lower_key; |
2063 | |
2064 | BUG_ON(path->nodes[level]); |
2065 | BUG_ON(path->nodes[level-1] != root->node); |
2066 | |
2067 | lower = path->nodes[level-1]; |
2068 | if (level == 1) |
2069 | btrfs_item_key(lower, &lower_key, 0); |
2070 | else |
2071 | btrfs_node_key(lower, &lower_key, 0); |
2072 | |
2073 | c = btrfs_alloc_free_block(trans, root, root->nodesize, 0, |
2074 | root->root_key.objectid, &lower_key, |
2075 | level, root->node->start, 0); |
2076 | if (IS_ERR(c)) |
2077 | return PTR_ERR(c); |
2078 | |
2079 | memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header)); |
2080 | btrfs_set_header_nritems(c, 1); |
2081 | btrfs_set_header_level(c, level); |
2082 | btrfs_set_header_bytenr(c, c->start); |
2083 | btrfs_set_header_generation(c, trans->transid); |
2084 | btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV); |
2085 | btrfs_set_header_owner(c, root->root_key.objectid); |
2086 | |
2087 | write_extent_buffer(c, root->fs_info->fsid, |
2088 | (unsigned long)btrfs_header_fsid(c), |
2089 | BTRFS_FSID_SIZE); |
2090 | |
2091 | write_extent_buffer(c, root->fs_info->chunk_tree_uuid, |
2092 | (unsigned long)btrfs_header_chunk_tree_uuid(c), |
2093 | BTRFS_UUID_SIZE); |
2094 | |
2095 | btrfs_set_node_key(c, &lower_key, 0); |
2096 | btrfs_set_node_blockptr(c, 0, lower->start); |
2097 | lower_gen = btrfs_header_generation(lower); |
2098 | WARN_ON(lower_gen != trans->transid); |
2099 | |
2100 | btrfs_set_node_ptr_generation(c, 0, lower_gen); |
2101 | |
2102 | btrfs_mark_buffer_dirty(c); |
2103 | |
2104 | spin_lock(&root->node_lock); |
2105 | old = root->node; |
2106 | root->node = c; |
2107 | spin_unlock(&root->node_lock); |
2108 | |
2109 | /* the super has an extra ref to root->node */ |
2110 | free_extent_buffer(old); |
2111 | |
2112 | add_root_to_dirty_list(root); |
2113 | extent_buffer_get(c); |
2114 | path->nodes[level] = c; |
2115 | path->locks[level] = 1; |
2116 | path->slots[level] = 0; |
2117 | return 0; |
2118 | } |
2119 | |
2120 | /* |
2121 | * worker function to insert a single pointer in a node. |
2122 | * the node should have enough room for the pointer already |
2123 | * |
2124 | * slot and level indicate where you want the key to go, and |
2125 | * blocknr is the block the key points to. |
2126 | * |
2127 | * returns zero on success and < 0 on any error |
2128 | */ |
2129 | static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root |
2130 | *root, struct btrfs_path *path, struct btrfs_disk_key |
2131 | *key, u64 bytenr, int slot, int level) |
2132 | { |
2133 | struct extent_buffer *lower; |
2134 | int nritems; |
2135 | |
2136 | BUG_ON(!path->nodes[level]); |
2137 | lower = path->nodes[level]; |
2138 | nritems = btrfs_header_nritems(lower); |
2139 | BUG_ON(slot > nritems); |
2140 | if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root)) |
2141 | BUG(); |
2142 | if (slot != nritems) { |
2143 | memmove_extent_buffer(lower, |
2144 | btrfs_node_key_ptr_offset(slot + 1), |
2145 | btrfs_node_key_ptr_offset(slot), |
2146 | (nritems - slot) * sizeof(struct btrfs_key_ptr)); |
2147 | } |
2148 | btrfs_set_node_key(lower, key, slot); |
2149 | btrfs_set_node_blockptr(lower, slot, bytenr); |
2150 | WARN_ON(trans->transid == 0); |
2151 | btrfs_set_node_ptr_generation(lower, slot, trans->transid); |
2152 | btrfs_set_header_nritems(lower, nritems + 1); |
2153 | btrfs_mark_buffer_dirty(lower); |
2154 | return 0; |
2155 | } |
2156 | |
2157 | /* |
2158 | * split the node at the specified level in path in two. |
2159 | * The path is corrected to point to the appropriate node after the split |
2160 | * |
2161 | * Before splitting this tries to make some room in the node by pushing |
2162 | * left and right, if either one works, it returns right away. |
2163 | * |
2164 | * returns 0 on success and < 0 on failure |
2165 | */ |
2166 | static noinline int split_node(struct btrfs_trans_handle *trans, |
2167 | struct btrfs_root *root, |
2168 | struct btrfs_path *path, int level) |
2169 | { |
2170 | struct extent_buffer *c; |
2171 | struct extent_buffer *split; |
2172 | struct btrfs_disk_key disk_key; |
2173 | int mid; |
2174 | int ret; |
2175 | int wret; |
2176 | u32 c_nritems; |
2177 | |
2178 | c = path->nodes[level]; |
2179 | WARN_ON(btrfs_header_generation(c) != trans->transid); |
2180 | if (c == root->node) { |
2181 | /* trying to split the root, lets make a new one */ |
2182 | ret = insert_new_root(trans, root, path, level + 1); |
2183 | if (ret) |
2184 | return ret; |
2185 | } else { |
2186 | ret = push_nodes_for_insert(trans, root, path, level); |
2187 | c = path->nodes[level]; |
2188 | if (!ret && btrfs_header_nritems(c) < |
2189 | BTRFS_NODEPTRS_PER_BLOCK(root) - 3) |
2190 | return 0; |
2191 | if (ret < 0) |
2192 | return ret; |
2193 | } |
2194 | |
2195 | c_nritems = btrfs_header_nritems(c); |
2196 | mid = (c_nritems + 1) / 2; |
2197 | btrfs_node_key(c, &disk_key, mid); |
2198 | |
2199 | split = btrfs_alloc_free_block(trans, root, root->nodesize, 0, |
2200 | root->root_key.objectid, |
2201 | &disk_key, level, c->start, 0); |
2202 | if (IS_ERR(split)) |
2203 | return PTR_ERR(split); |
2204 | |
2205 | memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header)); |
2206 | btrfs_set_header_level(split, btrfs_header_level(c)); |
2207 | btrfs_set_header_bytenr(split, split->start); |
2208 | btrfs_set_header_generation(split, trans->transid); |
2209 | btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV); |
2210 | btrfs_set_header_owner(split, root->root_key.objectid); |
2211 | write_extent_buffer(split, root->fs_info->fsid, |
2212 | (unsigned long)btrfs_header_fsid(split), |
2213 | BTRFS_FSID_SIZE); |
2214 | write_extent_buffer(split, root->fs_info->chunk_tree_uuid, |
2215 | (unsigned long)btrfs_header_chunk_tree_uuid(split), |
2216 | BTRFS_UUID_SIZE); |
2217 | |
2218 | |
2219 | copy_extent_buffer(split, c, |
2220 | btrfs_node_key_ptr_offset(0), |
2221 | btrfs_node_key_ptr_offset(mid), |
2222 | (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
2223 | btrfs_set_header_nritems(split, c_nritems - mid); |
2224 | btrfs_set_header_nritems(c, mid); |
2225 | ret = 0; |
2226 | |
2227 | btrfs_mark_buffer_dirty(c); |
2228 | btrfs_mark_buffer_dirty(split); |
2229 | |
2230 | wret = insert_ptr(trans, root, path, &disk_key, split->start, |
2231 | path->slots[level + 1] + 1, |
2232 | level + 1); |
2233 | if (wret) |
2234 | ret = wret; |
2235 | |
2236 | if (path->slots[level] >= mid) { |
2237 | path->slots[level] -= mid; |
2238 | btrfs_tree_unlock(c); |
2239 | free_extent_buffer(c); |
2240 | path->nodes[level] = split; |
2241 | path->slots[level + 1] += 1; |
2242 | } else { |
2243 | btrfs_tree_unlock(split); |
2244 | free_extent_buffer(split); |
2245 | } |
2246 | return ret; |
2247 | } |
2248 | |
2249 | /* |
2250 | * how many bytes are required to store the items in a leaf. start |
2251 | * and nr indicate which items in the leaf to check. This totals up the |
2252 | * space used both by the item structs and the item data |
2253 | */ |
2254 | static int leaf_space_used(struct extent_buffer *l, int start, int nr) |
2255 | { |
2256 | int data_len; |
2257 | int nritems = btrfs_header_nritems(l); |
2258 | int end = min(nritems, start + nr) - 1; |
2259 | |
2260 | if (!nr) |
2261 | return 0; |
2262 | data_len = btrfs_item_end_nr(l, start); |
2263 | data_len = data_len - btrfs_item_offset_nr(l, end); |
2264 | data_len += sizeof(struct btrfs_item) * nr; |
2265 | WARN_ON(data_len < 0); |
2266 | return data_len; |
2267 | } |
2268 | |
2269 | /* |
2270 | * The space between the end of the leaf items and |
2271 | * the start of the leaf data. IOW, how much room |
2272 | * the leaf has left for both items and data |
2273 | */ |
2274 | noinline int btrfs_leaf_free_space(struct btrfs_root *root, |
2275 | struct extent_buffer *leaf) |
2276 | { |
2277 | int nritems = btrfs_header_nritems(leaf); |
2278 | int ret; |
2279 | ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems); |
2280 | if (ret < 0) { |
2281 | printk(KERN_CRIT "leaf free space ret %d, leaf data size %lu, " |
2282 | "used %d nritems %d\n", |
2283 | ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root), |
2284 | leaf_space_used(leaf, 0, nritems), nritems); |
2285 | } |
2286 | return ret; |
2287 | } |
2288 | |
2289 | static noinline int __push_leaf_right(struct btrfs_trans_handle *trans, |
2290 | struct btrfs_root *root, |
2291 | struct btrfs_path *path, |
2292 | int data_size, int empty, |
2293 | struct extent_buffer *right, |
2294 | int free_space, u32 left_nritems) |
2295 | { |
2296 | struct extent_buffer *left = path->nodes[0]; |
2297 | struct extent_buffer *upper = path->nodes[1]; |
2298 | struct btrfs_disk_key disk_key; |
2299 | int slot; |
2300 | u32 i; |
2301 | int push_space = 0; |
2302 | int push_items = 0; |
2303 | struct btrfs_item *item; |
2304 | u32 nr; |
2305 | u32 right_nritems; |
2306 | u32 data_end; |
2307 | u32 this_item_size; |
2308 | |
2309 | if (empty) |
2310 | nr = 0; |
2311 | else |
2312 | nr = 1; |
2313 | |
2314 | if (path->slots[0] >= left_nritems) |
2315 | push_space += data_size; |
2316 | |
2317 | slot = path->slots[1]; |
2318 | i = left_nritems - 1; |
2319 | while (i >= nr) { |
2320 | item = btrfs_item_nr(left, i); |
2321 | |
2322 | if (!empty && push_items > 0) { |
2323 | if (path->slots[0] > i) |
2324 | break; |
2325 | if (path->slots[0] == i) { |
2326 | int space = btrfs_leaf_free_space(root, left); |
2327 | if (space + push_space * 2 > free_space) |
2328 | break; |
2329 | } |
2330 | } |
2331 | |
2332 | if (path->slots[0] == i) |
2333 | push_space += data_size; |
2334 | |
2335 | if (!left->map_token) { |
2336 | map_extent_buffer(left, (unsigned long)item, |
2337 | sizeof(struct btrfs_item), |
2338 | &left->map_token, &left->kaddr, |
2339 | &left->map_start, &left->map_len, |
2340 | KM_USER1); |
2341 | } |
2342 | |
2343 | this_item_size = btrfs_item_size(left, item); |
2344 | if (this_item_size + sizeof(*item) + push_space > free_space) |
2345 | break; |
2346 | |
2347 | push_items++; |
2348 | push_space += this_item_size + sizeof(*item); |
2349 | if (i == 0) |
2350 | break; |
2351 | i--; |
2352 | } |
2353 | if (left->map_token) { |
2354 | unmap_extent_buffer(left, left->map_token, KM_USER1); |
2355 | left->map_token = NULL; |
2356 | } |
2357 | |
2358 | if (push_items == 0) |
2359 | goto out_unlock; |
2360 | |
2361 | if (!empty && push_items == left_nritems) |
2362 | WARN_ON(1); |
2363 | |
2364 | /* push left to right */ |
2365 | right_nritems = btrfs_header_nritems(right); |
2366 | |
2367 | push_space = btrfs_item_end_nr(left, left_nritems - push_items); |
2368 | push_space -= leaf_data_end(root, left); |
2369 | |
2370 | /* make room in the right data area */ |
2371 | data_end = leaf_data_end(root, right); |
2372 | memmove_extent_buffer(right, |
2373 | btrfs_leaf_data(right) + data_end - push_space, |
2374 | btrfs_leaf_data(right) + data_end, |
2375 | BTRFS_LEAF_DATA_SIZE(root) - data_end); |
2376 | |
2377 | /* copy from the left data area */ |
2378 | copy_extent_buffer(right, left, btrfs_leaf_data(right) + |
2379 | BTRFS_LEAF_DATA_SIZE(root) - push_space, |
2380 | btrfs_leaf_data(left) + leaf_data_end(root, left), |
2381 | push_space); |
2382 | |
2383 | memmove_extent_buffer(right, btrfs_item_nr_offset(push_items), |
2384 | btrfs_item_nr_offset(0), |
2385 | right_nritems * sizeof(struct btrfs_item)); |
2386 | |
2387 | /* copy the items from left to right */ |
2388 | copy_extent_buffer(right, left, btrfs_item_nr_offset(0), |
2389 | btrfs_item_nr_offset(left_nritems - push_items), |
2390 | push_items * sizeof(struct btrfs_item)); |
2391 | |
2392 | /* update the item pointers */ |
2393 | right_nritems += push_items; |
2394 | btrfs_set_header_nritems(right, right_nritems); |
2395 | push_space = BTRFS_LEAF_DATA_SIZE(root); |
2396 | for (i = 0; i < right_nritems; i++) { |
2397 | item = btrfs_item_nr(right, i); |
2398 | if (!right->map_token) { |
2399 | map_extent_buffer(right, (unsigned long)item, |
2400 | sizeof(struct btrfs_item), |
2401 | &right->map_token, &right->kaddr, |
2402 | &right->map_start, &right->map_len, |
2403 | KM_USER1); |
2404 | } |
2405 | push_space -= btrfs_item_size(right, item); |
2406 | btrfs_set_item_offset(right, item, push_space); |
2407 | } |
2408 | |
2409 | if (right->map_token) { |
2410 | unmap_extent_buffer(right, right->map_token, KM_USER1); |
2411 | right->map_token = NULL; |
2412 | } |
2413 | left_nritems -= push_items; |
2414 | btrfs_set_header_nritems(left, left_nritems); |
2415 | |
2416 | if (left_nritems) |
2417 | btrfs_mark_buffer_dirty(left); |
2418 | btrfs_mark_buffer_dirty(right); |
2419 | |
2420 | btrfs_item_key(right, &disk_key, 0); |
2421 | btrfs_set_node_key(upper, &disk_key, slot + 1); |
2422 | btrfs_mark_buffer_dirty(upper); |
2423 | |
2424 | /* then fixup the leaf pointer in the path */ |
2425 | if (path->slots[0] >= left_nritems) { |
2426 | path->slots[0] -= left_nritems; |
2427 | if (btrfs_header_nritems(path->nodes[0]) == 0) |
2428 | clean_tree_block(trans, root, path->nodes[0]); |
2429 | btrfs_tree_unlock(path->nodes[0]); |
2430 | free_extent_buffer(path->nodes[0]); |
2431 | path->nodes[0] = right; |
2432 | path->slots[1] += 1; |
2433 | } else { |
2434 | btrfs_tree_unlock(right); |
2435 | free_extent_buffer(right); |
2436 | } |
2437 | return 0; |
2438 | |
2439 | out_unlock: |
2440 | btrfs_tree_unlock(right); |
2441 | free_extent_buffer(right); |
2442 | return 1; |
2443 | } |
2444 | |
2445 | /* |
2446 | * push some data in the path leaf to the right, trying to free up at |
2447 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
2448 | * |
2449 | * returns 1 if the push failed because the other node didn't have enough |
2450 | * room, 0 if everything worked out and < 0 if there were major errors. |
2451 | */ |
2452 | static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root |
2453 | *root, struct btrfs_path *path, int data_size, |
2454 | int empty) |
2455 | { |
2456 | struct extent_buffer *left = path->nodes[0]; |
2457 | struct extent_buffer *right; |
2458 | struct extent_buffer *upper; |
2459 | int slot; |
2460 | int free_space; |
2461 | u32 left_nritems; |
2462 | int ret; |
2463 | |
2464 | if (!path->nodes[1]) |
2465 | return 1; |
2466 | |
2467 | slot = path->slots[1]; |
2468 | upper = path->nodes[1]; |
2469 | if (slot >= btrfs_header_nritems(upper) - 1) |
2470 | return 1; |
2471 | |
2472 | btrfs_assert_tree_locked(path->nodes[1]); |
2473 | |
2474 | right = read_node_slot(root, upper, slot + 1); |
2475 | btrfs_tree_lock(right); |
2476 | btrfs_set_lock_blocking(right); |
2477 | |
2478 | free_space = btrfs_leaf_free_space(root, right); |
2479 | if (free_space < data_size) |
2480 | goto out_unlock; |
2481 | |
2482 | /* cow and double check */ |
2483 | ret = btrfs_cow_block(trans, root, right, upper, |
2484 | slot + 1, &right); |
2485 | if (ret) |
2486 | goto out_unlock; |
2487 | |
2488 | free_space = btrfs_leaf_free_space(root, right); |
2489 | if (free_space < data_size) |
2490 | goto out_unlock; |
2491 | |
2492 | left_nritems = btrfs_header_nritems(left); |
2493 | if (left_nritems == 0) |
2494 | goto out_unlock; |
2495 | |
2496 | return __push_leaf_right(trans, root, path, data_size, empty, |
2497 | right, free_space, left_nritems); |
2498 | out_unlock: |
2499 | btrfs_tree_unlock(right); |
2500 | free_extent_buffer(right); |
2501 | return 1; |
2502 | } |
2503 | |
2504 | /* |
2505 | * push some data in the path leaf to the left, trying to free up at |
2506 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
2507 | */ |
2508 | static noinline int __push_leaf_left(struct btrfs_trans_handle *trans, |
2509 | struct btrfs_root *root, |
2510 | struct btrfs_path *path, int data_size, |
2511 | int empty, struct extent_buffer *left, |
2512 | int free_space, int right_nritems) |
2513 | { |
2514 | struct btrfs_disk_key disk_key; |
2515 | struct extent_buffer *right = path->nodes[0]; |
2516 | int slot; |
2517 | int i; |
2518 | int push_space = 0; |
2519 | int push_items = 0; |
2520 | struct btrfs_item *item; |
2521 | u32 old_left_nritems; |
2522 | u32 nr; |
2523 | int ret = 0; |
2524 | int wret; |
2525 | u32 this_item_size; |
2526 | u32 old_left_item_size; |
2527 | |
2528 | slot = path->slots[1]; |
2529 | |
2530 | if (empty) |
2531 | nr = right_nritems; |
2532 | else |
2533 | nr = right_nritems - 1; |
2534 | |
2535 | for (i = 0; i < nr; i++) { |
2536 | item = btrfs_item_nr(right, i); |
2537 | if (!right->map_token) { |
2538 | map_extent_buffer(right, (unsigned long)item, |
2539 | sizeof(struct btrfs_item), |
2540 | &right->map_token, &right->kaddr, |
2541 | &right->map_start, &right->map_len, |
2542 | KM_USER1); |
2543 | } |
2544 | |
2545 | if (!empty && push_items > 0) { |
2546 | if (path->slots[0] < i) |
2547 | break; |
2548 | if (path->slots[0] == i) { |
2549 | int space = btrfs_leaf_free_space(root, right); |
2550 | if (space + push_space * 2 > free_space) |
2551 | break; |
2552 | } |
2553 | } |
2554 | |
2555 | if (path->slots[0] == i) |
2556 | push_space += data_size; |
2557 | |
2558 | this_item_size = btrfs_item_size(right, item); |
2559 | if (this_item_size + sizeof(*item) + push_space > free_space) |
2560 | break; |
2561 | |
2562 | push_items++; |
2563 | push_space += this_item_size + sizeof(*item); |
2564 | } |
2565 | |
2566 | if (right->map_token) { |
2567 | unmap_extent_buffer(right, right->map_token, KM_USER1); |
2568 | right->map_token = NULL; |
2569 | } |
2570 | |
2571 | if (push_items == 0) { |
2572 | ret = 1; |
2573 | goto out; |
2574 | } |
2575 | if (!empty && push_items == btrfs_header_nritems(right)) |
2576 | WARN_ON(1); |
2577 | |
2578 | /* push data from right to left */ |
2579 | copy_extent_buffer(left, right, |
2580 | btrfs_item_nr_offset(btrfs_header_nritems(left)), |
2581 | btrfs_item_nr_offset(0), |
2582 | push_items * sizeof(struct btrfs_item)); |
2583 | |
2584 | push_space = BTRFS_LEAF_DATA_SIZE(root) - |
2585 | btrfs_item_offset_nr(right, push_items - 1); |
2586 | |
2587 | copy_extent_buffer(left, right, btrfs_leaf_data(left) + |
2588 | leaf_data_end(root, left) - push_space, |
2589 | btrfs_leaf_data(right) + |
2590 | btrfs_item_offset_nr(right, push_items - 1), |
2591 | push_space); |
2592 | old_left_nritems = btrfs_header_nritems(left); |
2593 | BUG_ON(old_left_nritems <= 0); |
2594 | |
2595 | old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1); |
2596 | for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { |
2597 | u32 ioff; |
2598 | |
2599 | item = btrfs_item_nr(left, i); |
2600 | if (!left->map_token) { |
2601 | map_extent_buffer(left, (unsigned long)item, |
2602 | sizeof(struct btrfs_item), |
2603 | &left->map_token, &left->kaddr, |
2604 | &left->map_start, &left->map_len, |
2605 | KM_USER1); |
2606 | } |
2607 | |
2608 | ioff = btrfs_item_offset(left, item); |
2609 | btrfs_set_item_offset(left, item, |
2610 | ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size)); |
2611 | } |
2612 | btrfs_set_header_nritems(left, old_left_nritems + push_items); |
2613 | if (left->map_token) { |
2614 | unmap_extent_buffer(left, left->map_token, KM_USER1); |
2615 | left->map_token = NULL; |
2616 | } |
2617 | |
2618 | /* fixup right node */ |
2619 | if (push_items > right_nritems) { |
2620 | printk(KERN_CRIT "push items %d nr %u\n", push_items, |
2621 | right_nritems); |
2622 | WARN_ON(1); |
2623 | } |
2624 | |
2625 | if (push_items < right_nritems) { |
2626 | push_space = btrfs_item_offset_nr(right, push_items - 1) - |
2627 | leaf_data_end(root, right); |
2628 | memmove_extent_buffer(right, btrfs_leaf_data(right) + |
2629 | BTRFS_LEAF_DATA_SIZE(root) - push_space, |
2630 | btrfs_leaf_data(right) + |
2631 | leaf_data_end(root, right), push_space); |
2632 | |
2633 | memmove_extent_buffer(right, btrfs_item_nr_offset(0), |
2634 | btrfs_item_nr_offset(push_items), |
2635 | (btrfs_header_nritems(right) - push_items) * |
2636 | sizeof(struct btrfs_item)); |
2637 | } |
2638 | right_nritems -= push_items; |
2639 | btrfs_set_header_nritems(right, right_nritems); |
2640 | push_space = BTRFS_LEAF_DATA_SIZE(root); |
2641 | for (i = 0; i < right_nritems; i++) { |
2642 | item = btrfs_item_nr(right, i); |
2643 | |
2644 | if (!right->map_token) { |
2645 | map_extent_buffer(right, (unsigned long)item, |
2646 | sizeof(struct btrfs_item), |
2647 | &right->map_token, &right->kaddr, |
2648 | &right->map_start, &right->map_len, |
2649 | KM_USER1); |
2650 | } |
2651 | |
2652 | push_space = push_space - btrfs_item_size(right, item); |
2653 | btrfs_set_item_offset(right, item, push_space); |
2654 | } |
2655 | if (right->map_token) { |
2656 | unmap_extent_buffer(right, right->map_token, KM_USER1); |
2657 | right->map_token = NULL; |
2658 | } |
2659 | |
2660 | btrfs_mark_buffer_dirty(left); |
2661 | if (right_nritems) |
2662 | btrfs_mark_buffer_dirty(right); |
2663 | |
2664 | btrfs_item_key(right, &disk_key, 0); |
2665 | wret = fixup_low_keys(trans, root, path, &disk_key, 1); |
2666 | if (wret) |
2667 | ret = wret; |
2668 | |
2669 | /* then fixup the leaf pointer in the path */ |
2670 | if (path->slots[0] < push_items) { |
2671 | path->slots[0] += old_left_nritems; |
2672 | if (btrfs_header_nritems(path->nodes[0]) == 0) |
2673 | clean_tree_block(trans, root, path->nodes[0]); |
2674 | btrfs_tree_unlock(path->nodes[0]); |
2675 | free_extent_buffer(path->nodes[0]); |
2676 | path->nodes[0] = left; |
2677 | path->slots[1] -= 1; |
2678 | } else { |
2679 | btrfs_tree_unlock(left); |
2680 | free_extent_buffer(left); |
2681 | path->slots[0] -= push_items; |
2682 | } |
2683 | BUG_ON(path->slots[0] < 0); |
2684 | return ret; |
2685 | out: |
2686 | btrfs_tree_unlock(left); |
2687 | free_extent_buffer(left); |
2688 | return ret; |
2689 | } |
2690 | |
2691 | /* |
2692 | * push some data in the path leaf to the left, trying to free up at |
2693 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
2694 | */ |
2695 | static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root |
2696 | *root, struct btrfs_path *path, int data_size, |
2697 | int empty) |
2698 | { |
2699 | struct extent_buffer *right = path->nodes[0]; |
2700 | struct extent_buffer *left; |
2701 | int slot; |
2702 | int free_space; |
2703 | u32 right_nritems; |
2704 | int ret = 0; |
2705 | |
2706 | slot = path->slots[1]; |
2707 | if (slot == 0) |
2708 | return 1; |
2709 | if (!path->nodes[1]) |
2710 | return 1; |
2711 | |
2712 | right_nritems = btrfs_header_nritems(right); |
2713 | if (right_nritems == 0) |
2714 | return 1; |
2715 | |
2716 | btrfs_assert_tree_locked(path->nodes[1]); |
2717 | |
2718 | left = read_node_slot(root, path->nodes[1], slot - 1); |
2719 | btrfs_tree_lock(left); |
2720 | btrfs_set_lock_blocking(left); |
2721 | |
2722 | free_space = btrfs_leaf_free_space(root, left); |
2723 | if (free_space < data_size) { |
2724 | ret = 1; |
2725 | goto out; |
2726 | } |
2727 | |
2728 | /* cow and double check */ |
2729 | ret = btrfs_cow_block(trans, root, left, |
2730 | path->nodes[1], slot - 1, &left); |
2731 | if (ret) { |
2732 | /* we hit -ENOSPC, but it isn't fatal here */ |
2733 | ret = 1; |
2734 | goto out; |
2735 | } |
2736 | |
2737 | free_space = btrfs_leaf_free_space(root, left); |
2738 | if (free_space < data_size) { |
2739 | ret = 1; |
2740 | goto out; |
2741 | } |
2742 | |
2743 | return __push_leaf_left(trans, root, path, data_size, |
2744 | empty, left, free_space, right_nritems); |
2745 | out: |
2746 | btrfs_tree_unlock(left); |
2747 | free_extent_buffer(left); |
2748 | return ret; |
2749 | } |
2750 | |
2751 | /* |
2752 | * split the path's leaf in two, making sure there is at least data_size |
2753 | * available for the resulting leaf level of the path. |
2754 | * |
2755 | * returns 0 if all went well and < 0 on failure. |
2756 | */ |
2757 | static noinline int copy_for_split(struct btrfs_trans_handle *trans, |
2758 | struct btrfs_root *root, |
2759 | struct btrfs_path *path, |
2760 | struct extent_buffer *l, |
2761 | struct extent_buffer *right, |
2762 | int slot, int mid, int nritems) |
2763 | { |
2764 | int data_copy_size; |
2765 | int rt_data_off; |
2766 | int i; |
2767 | int ret = 0; |
2768 | int wret; |
2769 | struct btrfs_disk_key disk_key; |
2770 | |
2771 | nritems = nritems - mid; |
2772 | btrfs_set_header_nritems(right, nritems); |
2773 | data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l); |
2774 | |
2775 | copy_extent_buffer(right, l, btrfs_item_nr_offset(0), |
2776 | btrfs_item_nr_offset(mid), |
2777 | nritems * sizeof(struct btrfs_item)); |
2778 | |
2779 | copy_extent_buffer(right, l, |
2780 | btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) - |
2781 | data_copy_size, btrfs_leaf_data(l) + |
2782 | leaf_data_end(root, l), data_copy_size); |
2783 | |
2784 | rt_data_off = BTRFS_LEAF_DATA_SIZE(root) - |
2785 | btrfs_item_end_nr(l, mid); |
2786 | |
2787 | for (i = 0; i < nritems; i++) { |
2788 | struct btrfs_item *item = btrfs_item_nr(right, i); |
2789 | u32 ioff; |
2790 | |
2791 | if (!right->map_token) { |
2792 | map_extent_buffer(right, (unsigned long)item, |
2793 | sizeof(struct btrfs_item), |
2794 | &right->map_token, &right->kaddr, |
2795 | &right->map_start, &right->map_len, |
2796 | KM_USER1); |
2797 | } |
2798 | |
2799 | ioff = btrfs_item_offset(right, item); |
2800 | btrfs_set_item_offset(right, item, ioff + rt_data_off); |
2801 | } |
2802 | |
2803 | if (right->map_token) { |
2804 | unmap_extent_buffer(right, right->map_token, KM_USER1); |
2805 | right->map_token = NULL; |
2806 | } |
2807 | |
2808 | btrfs_set_header_nritems(l, mid); |
2809 | ret = 0; |
2810 | btrfs_item_key(right, &disk_key, 0); |
2811 | wret = insert_ptr(trans, root, path, &disk_key, right->start, |
2812 | path->slots[1] + 1, 1); |
2813 | if (wret) |
2814 | ret = wret; |
2815 | |
2816 | btrfs_mark_buffer_dirty(right); |
2817 | btrfs_mark_buffer_dirty(l); |
2818 | BUG_ON(path->slots[0] != slot); |
2819 | |
2820 | if (mid <= slot) { |
2821 | btrfs_tree_unlock(path->nodes[0]); |
2822 | free_extent_buffer(path->nodes[0]); |
2823 | path->nodes[0] = right; |
2824 | path->slots[0] -= mid; |
2825 | path->slots[1] += 1; |
2826 | } else { |
2827 | btrfs_tree_unlock(right); |
2828 | free_extent_buffer(right); |
2829 | } |
2830 | |
2831 | BUG_ON(path->slots[0] < 0); |
2832 | |
2833 | return ret; |
2834 | } |
2835 | |
2836 | /* |
2837 | * split the path's leaf in two, making sure there is at least data_size |
2838 | * available for the resulting leaf level of the path. |
2839 | * |
2840 | * returns 0 if all went well and < 0 on failure. |
2841 | */ |
2842 | static noinline int split_leaf(struct btrfs_trans_handle *trans, |
2843 | struct btrfs_root *root, |
2844 | struct btrfs_key *ins_key, |
2845 | struct btrfs_path *path, int data_size, |
2846 | int extend) |
2847 | { |
2848 | struct btrfs_disk_key disk_key; |
2849 | struct extent_buffer *l; |
2850 | u32 nritems; |
2851 | int mid; |
2852 | int slot; |
2853 | struct extent_buffer *right; |
2854 | int ret = 0; |
2855 | int wret; |
2856 | int split; |
2857 | int num_doubles = 0; |
2858 | |
2859 | l = path->nodes[0]; |
2860 | slot = path->slots[0]; |
2861 | if (extend && data_size + btrfs_item_size_nr(l, slot) + |
2862 | sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root)) |
2863 | return -EOVERFLOW; |
2864 | |
2865 | /* first try to make some room by pushing left and right */ |
2866 | if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) { |
2867 | wret = push_leaf_right(trans, root, path, data_size, 0); |
2868 | if (wret < 0) |
2869 | return wret; |
2870 | if (wret) { |
2871 | wret = push_leaf_left(trans, root, path, data_size, 0); |
2872 | if (wret < 0) |
2873 | return wret; |
2874 | } |
2875 | l = path->nodes[0]; |
2876 | |
2877 | /* did the pushes work? */ |
2878 | if (btrfs_leaf_free_space(root, l) >= data_size) |
2879 | return 0; |
2880 | } |
2881 | |
2882 | if (!path->nodes[1]) { |
2883 | ret = insert_new_root(trans, root, path, 1); |
2884 | if (ret) |
2885 | return ret; |
2886 | } |
2887 | again: |
2888 | split = 1; |
2889 | l = path->nodes[0]; |
2890 | slot = path->slots[0]; |
2891 | nritems = btrfs_header_nritems(l); |
2892 | mid = (nritems + 1) / 2; |
2893 | |
2894 | if (mid <= slot) { |
2895 | if (nritems == 1 || |
2896 | leaf_space_used(l, mid, nritems - mid) + data_size > |
2897 | BTRFS_LEAF_DATA_SIZE(root)) { |
2898 | if (slot >= nritems) { |
2899 | split = 0; |
2900 | } else { |
2901 | mid = slot; |
2902 | if (mid != nritems && |
2903 | leaf_space_used(l, mid, nritems - mid) + |
2904 | data_size > BTRFS_LEAF_DATA_SIZE(root)) { |
2905 | split = 2; |
2906 | } |
2907 | } |
2908 | } |
2909 | } else { |
2910 | if (leaf_space_used(l, 0, mid) + data_size > |
2911 | BTRFS_LEAF_DATA_SIZE(root)) { |
2912 | if (!extend && data_size && slot == 0) { |
2913 | split = 0; |
2914 | } else if ((extend || !data_size) && slot == 0) { |
2915 | mid = 1; |
2916 | } else { |
2917 | mid = slot; |
2918 | if (mid != nritems && |
2919 | leaf_space_used(l, mid, nritems - mid) + |
2920 | data_size > BTRFS_LEAF_DATA_SIZE(root)) { |
2921 | split = 2 ; |
2922 | } |
2923 | } |
2924 | } |
2925 | } |
2926 | |
2927 | if (split == 0) |
2928 | btrfs_cpu_key_to_disk(&disk_key, ins_key); |
2929 | else |
2930 | btrfs_item_key(l, &disk_key, mid); |
2931 | |
2932 | right = btrfs_alloc_free_block(trans, root, root->leafsize, 0, |
2933 | root->root_key.objectid, |
2934 | &disk_key, 0, l->start, 0); |
2935 | if (IS_ERR(right)) { |
2936 | BUG_ON(1); |
2937 | return PTR_ERR(right); |
2938 | } |
2939 | |
2940 | memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header)); |
2941 | btrfs_set_header_bytenr(right, right->start); |
2942 | btrfs_set_header_generation(right, trans->transid); |
2943 | btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV); |
2944 | btrfs_set_header_owner(right, root->root_key.objectid); |
2945 | btrfs_set_header_level(right, 0); |
2946 | write_extent_buffer(right, root->fs_info->fsid, |
2947 | (unsigned long)btrfs_header_fsid(right), |
2948 | BTRFS_FSID_SIZE); |
2949 | |
2950 | write_extent_buffer(right, root->fs_info->chunk_tree_uuid, |
2951 | (unsigned long)btrfs_header_chunk_tree_uuid(right), |
2952 | BTRFS_UUID_SIZE); |
2953 | |
2954 | if (split == 0) { |
2955 | if (mid <= slot) { |
2956 | btrfs_set_header_nritems(right, 0); |
2957 | wret = insert_ptr(trans, root, path, |
2958 | &disk_key, right->start, |
2959 | path->slots[1] + 1, 1); |
2960 | if (wret) |
2961 | ret = wret; |
2962 | |
2963 | btrfs_tree_unlock(path->nodes[0]); |
2964 | free_extent_buffer(path->nodes[0]); |
2965 | path->nodes[0] = right; |
2966 | path->slots[0] = 0; |
2967 | path->slots[1] += 1; |
2968 | } else { |
2969 | btrfs_set_header_nritems(right, 0); |
2970 | wret = insert_ptr(trans, root, path, |
2971 | &disk_key, |
2972 | right->start, |
2973 | path->slots[1], 1); |
2974 | if (wret) |
2975 | ret = wret; |
2976 | btrfs_tree_unlock(path->nodes[0]); |
2977 | free_extent_buffer(path->nodes[0]); |
2978 | path->nodes[0] = right; |
2979 | path->slots[0] = 0; |
2980 | if (path->slots[1] == 0) { |
2981 | wret = fixup_low_keys(trans, root, |
2982 | path, &disk_key, 1); |
2983 | if (wret) |
2984 | ret = wret; |
2985 | } |
2986 | } |
2987 | btrfs_mark_buffer_dirty(right); |
2988 | return ret; |
2989 | } |
2990 | |
2991 | ret = copy_for_split(trans, root, path, l, right, slot, mid, nritems); |
2992 | BUG_ON(ret); |
2993 | |
2994 | if (split == 2) { |
2995 | BUG_ON(num_doubles != 0); |
2996 | num_doubles++; |
2997 | goto again; |
2998 | } |
2999 | |
3000 | return ret; |
3001 | } |
3002 | |
3003 | static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, |
3004 | struct btrfs_root *root, |
3005 | struct btrfs_path *path, int ins_len) |
3006 | { |
3007 | struct btrfs_key key; |
3008 | struct extent_buffer *leaf; |
3009 | struct btrfs_file_extent_item *fi; |
3010 | u64 extent_len = 0; |
3011 | u32 item_size; |
3012 | int ret; |
3013 | |
3014 | leaf = path->nodes[0]; |
3015 | btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); |
3016 | |
3017 | BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY && |
3018 | key.type != BTRFS_EXTENT_CSUM_KEY); |
3019 | |
3020 | if (btrfs_leaf_free_space(root, leaf) >= ins_len) |
3021 | return 0; |
3022 | |
3023 | item_size = btrfs_item_size_nr(leaf, path->slots[0]); |
3024 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
3025 | fi = btrfs_item_ptr(leaf, path->slots[0], |
3026 | struct btrfs_file_extent_item); |
3027 | extent_len = btrfs_file_extent_num_bytes(leaf, fi); |
3028 | } |
3029 | btrfs_release_path(root, path); |
3030 | |
3031 | path->keep_locks = 1; |
3032 | path->search_for_split = 1; |
3033 | ret = btrfs_search_slot(trans, root, &key, path, 0, 1); |
3034 | path->search_for_split = 0; |
3035 | if (ret < 0) |
3036 | goto err; |
3037 | |
3038 | ret = -EAGAIN; |
3039 | leaf = path->nodes[0]; |
3040 | /* if our item isn't there or got smaller, return now */ |
3041 | if (ret > 0 || item_size != btrfs_item_size_nr(leaf, path->slots[0])) |
3042 | goto err; |
3043 | |
3044 | /* the leaf has changed, it now has room. return now */ |
3045 | if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len) |
3046 | goto err; |
3047 | |
3048 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
3049 | fi = btrfs_item_ptr(leaf, path->slots[0], |
3050 | struct btrfs_file_extent_item); |
3051 | if (extent_len != btrfs_file_extent_num_bytes(leaf, fi)) |
3052 | goto err; |
3053 | } |
3054 | |
3055 | btrfs_set_path_blocking(path); |
3056 | ret = split_leaf(trans, root, &key, path, ins_len, 1); |
3057 | BUG_ON(ret); |
3058 | |
3059 | path->keep_locks = 0; |
3060 | btrfs_unlock_up_safe(path, 1); |
3061 | return 0; |
3062 | err: |
3063 | path->keep_locks = 0; |
3064 | return ret; |
3065 | } |
3066 | |
3067 | static noinline int split_item(struct btrfs_trans_handle *trans, |
3068 | struct btrfs_root *root, |
3069 | struct btrfs_path *path, |
3070 | struct btrfs_key *new_key, |
3071 | unsigned long split_offset) |
3072 | { |
3073 | struct extent_buffer *leaf; |
3074 | struct btrfs_item *item; |
3075 | struct btrfs_item *new_item; |
3076 | int slot; |
3077 | char *buf; |
3078 | u32 nritems; |
3079 | u32 item_size; |
3080 | u32 orig_offset; |
3081 | struct btrfs_disk_key disk_key; |
3082 | |
3083 | leaf = path->nodes[0]; |
3084 | BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); |
3085 | |
3086 | btrfs_set_path_blocking(path); |
3087 | |
3088 | item = btrfs_item_nr(leaf, path->slots[0]); |
3089 | orig_offset = btrfs_item_offset(leaf, item); |
3090 | item_size = btrfs_item_size(leaf, item); |
3091 | |
3092 | buf = kmalloc(item_size, GFP_NOFS); |
3093 | if (!buf) |
3094 | return -ENOMEM; |
3095 | |
3096 | read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, |
3097 | path->slots[0]), item_size); |
3098 | |
3099 | slot = path->slots[0] + 1; |
3100 | nritems = btrfs_header_nritems(leaf); |
3101 | if (slot != nritems) { |
3102 | /* shift the items */ |
3103 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1), |
3104 | btrfs_item_nr_offset(slot), |
3105 | (nritems - slot) * sizeof(struct btrfs_item)); |
3106 | } |
3107 | |
3108 | btrfs_cpu_key_to_disk(&disk_key, new_key); |
3109 | btrfs_set_item_key(leaf, &disk_key, slot); |
3110 | |
3111 | new_item = btrfs_item_nr(leaf, slot); |
3112 | |
3113 | btrfs_set_item_offset(leaf, new_item, orig_offset); |
3114 | btrfs_set_item_size(leaf, new_item, item_size - split_offset); |
3115 | |
3116 | btrfs_set_item_offset(leaf, item, |
3117 | orig_offset + item_size - split_offset); |
3118 | btrfs_set_item_size(leaf, item, split_offset); |
3119 | |
3120 | btrfs_set_header_nritems(leaf, nritems + 1); |
3121 | |
3122 | /* write the data for the start of the original item */ |
3123 | write_extent_buffer(leaf, buf, |
3124 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
3125 | split_offset); |
3126 | |
3127 | /* write the data for the new item */ |
3128 | write_extent_buffer(leaf, buf + split_offset, |
3129 | btrfs_item_ptr_offset(leaf, slot), |
3130 | item_size - split_offset); |
3131 | btrfs_mark_buffer_dirty(leaf); |
3132 | |
3133 | BUG_ON(btrfs_leaf_free_space(root, leaf) < 0); |
3134 | kfree(buf); |
3135 | return 0; |
3136 | } |
3137 | |
3138 | /* |
3139 | * This function splits a single item into two items, |
3140 | * giving 'new_key' to the new item and splitting the |
3141 | * old one at split_offset (from the start of the item). |
3142 | * |
3143 | * The path may be released by this operation. After |
3144 | * the split, the path is pointing to the old item. The |
3145 | * new item is going to be in the same node as the old one. |
3146 | * |
3147 | * Note, the item being split must be smaller enough to live alone on |
3148 | * a tree block with room for one extra struct btrfs_item |
3149 | * |
3150 | * This allows us to split the item in place, keeping a lock on the |
3151 | * leaf the entire time. |
3152 | */ |
3153 | int btrfs_split_item(struct btrfs_trans_handle *trans, |
3154 | struct btrfs_root *root, |
3155 | struct btrfs_path *path, |
3156 | struct btrfs_key *new_key, |
3157 | unsigned long split_offset) |
3158 | { |
3159 | int ret; |
3160 | ret = setup_leaf_for_split(trans, root, path, |
3161 | sizeof(struct btrfs_item)); |
3162 | if (ret) |
3163 | return ret; |
3164 | |
3165 | ret = split_item(trans, root, path, new_key, split_offset); |
3166 | return ret; |
3167 | } |
3168 | |
3169 | /* |
3170 | * This function duplicate a item, giving 'new_key' to the new item. |
3171 | * It guarantees both items live in the same tree leaf and the new item |
3172 | * is contiguous with the original item. |
3173 | * |
3174 | * This allows us to split file extent in place, keeping a lock on the |
3175 | * leaf the entire time. |
3176 | */ |
3177 | int btrfs_duplicate_item(struct btrfs_trans_handle *trans, |
3178 | struct btrfs_root *root, |
3179 | struct btrfs_path *path, |
3180 | struct btrfs_key *new_key) |
3181 | { |
3182 | struct extent_buffer *leaf; |
3183 | int ret; |
3184 | u32 item_size; |
3185 | |
3186 | leaf = path->nodes[0]; |
3187 | item_size = btrfs_item_size_nr(leaf, path->slots[0]); |
3188 | ret = setup_leaf_for_split(trans, root, path, |
3189 | item_size + sizeof(struct btrfs_item)); |
3190 | if (ret) |
3191 | return ret; |
3192 | |
3193 | path->slots[0]++; |
3194 | ret = setup_items_for_insert(trans, root, path, new_key, &item_size, |
3195 | item_size, item_size + |
3196 | sizeof(struct btrfs_item), 1); |
3197 | BUG_ON(ret); |
3198 | |
3199 | leaf = path->nodes[0]; |
3200 | memcpy_extent_buffer(leaf, |
3201 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
3202 | btrfs_item_ptr_offset(leaf, path->slots[0] - 1), |
3203 | item_size); |
3204 | return 0; |
3205 | } |
3206 | |
3207 | /* |
3208 | * make the item pointed to by the path smaller. new_size indicates |
3209 | * how small to make it, and from_end tells us if we just chop bytes |
3210 | * off the end of the item or if we shift the item to chop bytes off |
3211 | * the front. |
3212 | */ |
3213 | int btrfs_truncate_item(struct btrfs_trans_handle *trans, |
3214 | struct btrfs_root *root, |
3215 | struct btrfs_path *path, |
3216 | u32 new_size, int from_end) |
3217 | { |
3218 | int ret = 0; |
3219 | int slot; |
3220 | int slot_orig; |
3221 | struct extent_buffer *leaf; |
3222 | struct btrfs_item *item; |
3223 | u32 nritems; |
3224 | unsigned int data_end; |
3225 | unsigned int old_data_start; |
3226 | unsigned int old_size; |
3227 | unsigned int size_diff; |
3228 | int i; |
3229 | |
3230 | slot_orig = path->slots[0]; |
3231 | leaf = path->nodes[0]; |
3232 | slot = path->slots[0]; |
3233 | |
3234 | old_size = btrfs_item_size_nr(leaf, slot); |
3235 | if (old_size == new_size) |
3236 | return 0; |
3237 | |
3238 | nritems = btrfs_header_nritems(leaf); |
3239 | data_end = leaf_data_end(root, leaf); |
3240 | |
3241 | old_data_start = btrfs_item_offset_nr(leaf, slot); |
3242 | |
3243 | size_diff = old_size - new_size; |
3244 | |
3245 | BUG_ON(slot < 0); |
3246 | BUG_ON(slot >= nritems); |
3247 | |
3248 | /* |
3249 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
3250 | */ |
3251 | /* first correct the data pointers */ |
3252 | for (i = slot; i < nritems; i++) { |
3253 | u32 ioff; |
3254 | item = btrfs_item_nr(leaf, i); |
3255 | |
3256 | if (!leaf->map_token) { |
3257 | map_extent_buffer(leaf, (unsigned long)item, |
3258 | sizeof(struct btrfs_item), |
3259 | &leaf->map_token, &leaf->kaddr, |
3260 | &leaf->map_start, &leaf->map_len, |
3261 | KM_USER1); |
3262 | } |
3263 | |
3264 | ioff = btrfs_item_offset(leaf, item); |
3265 | btrfs_set_item_offset(leaf, item, ioff + size_diff); |
3266 | } |
3267 | |
3268 | if (leaf->map_token) { |
3269 | unmap_extent_buffer(leaf, leaf->map_token, KM_USER1); |
3270 | leaf->map_token = NULL; |
3271 | } |
3272 | |
3273 | /* shift the data */ |
3274 | if (from_end) { |
3275 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
3276 | data_end + size_diff, btrfs_leaf_data(leaf) + |
3277 | data_end, old_data_start + new_size - data_end); |
3278 | } else { |
3279 | struct btrfs_disk_key disk_key; |
3280 | u64 offset; |
3281 | |
3282 | btrfs_item_key(leaf, &disk_key, slot); |
3283 | |
3284 | if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) { |
3285 | unsigned long ptr; |
3286 | struct btrfs_file_extent_item *fi; |
3287 | |
3288 | fi = btrfs_item_ptr(leaf, slot, |
3289 | struct btrfs_file_extent_item); |
3290 | fi = (struct btrfs_file_extent_item *)( |
3291 | (unsigned long)fi - size_diff); |
3292 | |
3293 | if (btrfs_file_extent_type(leaf, fi) == |
3294 | BTRFS_FILE_EXTENT_INLINE) { |
3295 | ptr = btrfs_item_ptr_offset(leaf, slot); |
3296 | memmove_extent_buffer(leaf, ptr, |
3297 | (unsigned long)fi, |
3298 | offsetof(struct btrfs_file_extent_item, |
3299 | disk_bytenr)); |
3300 | } |
3301 | } |
3302 | |
3303 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
3304 | data_end + size_diff, btrfs_leaf_data(leaf) + |
3305 | data_end, old_data_start - data_end); |
3306 | |
3307 | offset = btrfs_disk_key_offset(&disk_key); |
3308 | btrfs_set_disk_key_offset(&disk_key, offset + size_diff); |
3309 | btrfs_set_item_key(leaf, &disk_key, slot); |
3310 | if (slot == 0) |
3311 | fixup_low_keys(trans, root, path, &disk_key, 1); |
3312 | } |
3313 | |
3314 | item = btrfs_item_nr(leaf, slot); |
3315 | btrfs_set_item_size(leaf, item, new_size); |
3316 | btrfs_mark_buffer_dirty(leaf); |
3317 | |
3318 | ret = 0; |
3319 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
3320 | btrfs_print_leaf(root, leaf); |
3321 | BUG(); |
3322 | } |
3323 | return ret; |
3324 | } |
3325 | |
3326 | /* |
3327 | * make the item pointed to by the path bigger, data_size is the new size. |
3328 | */ |
3329 | int btrfs_extend_item(struct btrfs_trans_handle *trans, |
3330 | struct btrfs_root *root, struct btrfs_path *path, |
3331 | u32 data_size) |
3332 | { |
3333 | int ret = 0; |
3334 | int slot; |
3335 | int slot_orig; |
3336 | struct extent_buffer *leaf; |
3337 | struct btrfs_item *item; |
3338 | u32 nritems; |
3339 | unsigned int data_end; |
3340 | unsigned int old_data; |
3341 | unsigned int old_size; |
3342 | int i; |
3343 | |
3344 | slot_orig = path->slots[0]; |
3345 | leaf = path->nodes[0]; |
3346 | |
3347 | nritems = btrfs_header_nritems(leaf); |
3348 | data_end = leaf_data_end(root, leaf); |
3349 | |
3350 | if (btrfs_leaf_free_space(root, leaf) < data_size) { |
3351 | btrfs_print_leaf(root, leaf); |
3352 | BUG(); |
3353 | } |
3354 | slot = path->slots[0]; |
3355 | old_data = btrfs_item_end_nr(leaf, slot); |
3356 | |
3357 | BUG_ON(slot < 0); |
3358 | if (slot >= nritems) { |
3359 | btrfs_print_leaf(root, leaf); |
3360 | printk(KERN_CRIT "slot %d too large, nritems %d\n", |
3361 | slot, nritems); |
3362 | BUG_ON(1); |
3363 | } |
3364 | |
3365 | /* |
3366 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
3367 | */ |
3368 | /* first correct the data pointers */ |
3369 | for (i = slot; i < nritems; i++) { |
3370 | u32 ioff; |
3371 | item = btrfs_item_nr(leaf, i); |
3372 | |
3373 | if (!leaf->map_token) { |
3374 | map_extent_buffer(leaf, (unsigned long)item, |
3375 | sizeof(struct btrfs_item), |
3376 | &leaf->map_token, &leaf->kaddr, |
3377 | &leaf->map_start, &leaf->map_len, |
3378 | KM_USER1); |
3379 | } |
3380 | ioff = btrfs_item_offset(leaf, item); |
3381 | btrfs_set_item_offset(leaf, item, ioff - data_size); |
3382 | } |
3383 | |
3384 | if (leaf->map_token) { |
3385 | unmap_extent_buffer(leaf, leaf->map_token, KM_USER1); |
3386 | leaf->map_token = NULL; |
3387 | } |
3388 | |
3389 | /* shift the data */ |
3390 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
3391 | data_end - data_size, btrfs_leaf_data(leaf) + |
3392 | data_end, old_data - data_end); |
3393 | |
3394 | data_end = old_data; |
3395 | old_size = btrfs_item_size_nr(leaf, slot); |
3396 | item = btrfs_item_nr(leaf, slot); |
3397 | btrfs_set_item_size(leaf, item, old_size + data_size); |
3398 | btrfs_mark_buffer_dirty(leaf); |
3399 | |
3400 | ret = 0; |
3401 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
3402 | btrfs_print_leaf(root, leaf); |
3403 | BUG(); |
3404 | } |
3405 | return ret; |
3406 | } |
3407 | |
3408 | /* |
3409 | * Given a key and some data, insert items into the tree. |
3410 | * This does all the path init required, making room in the tree if needed. |
3411 | * Returns the number of keys that were inserted. |
3412 | */ |
3413 | int btrfs_insert_some_items(struct btrfs_trans_handle *trans, |
3414 | struct btrfs_root *root, |
3415 | struct btrfs_path *path, |
3416 | struct btrfs_key *cpu_key, u32 *data_size, |
3417 | int nr) |
3418 | { |
3419 | struct extent_buffer *leaf; |
3420 | struct btrfs_item *item; |
3421 | int ret = 0; |
3422 | int slot; |
3423 | int i; |
3424 | u32 nritems; |
3425 | u32 total_data = 0; |
3426 | u32 total_size = 0; |
3427 | unsigned int data_end; |
3428 | struct btrfs_disk_key disk_key; |
3429 | struct btrfs_key found_key; |
3430 | |
3431 | for (i = 0; i < nr; i++) { |
3432 | if (total_size + data_size[i] + sizeof(struct btrfs_item) > |
3433 | BTRFS_LEAF_DATA_SIZE(root)) { |
3434 | break; |
3435 | nr = i; |
3436 | } |
3437 | total_data += data_size[i]; |
3438 | total_size += data_size[i] + sizeof(struct btrfs_item); |
3439 | } |
3440 | BUG_ON(nr == 0); |
3441 | |
3442 | ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1); |
3443 | if (ret == 0) |
3444 | return -EEXIST; |
3445 | if (ret < 0) |
3446 | goto out; |
3447 | |
3448 | leaf = path->nodes[0]; |
3449 | |
3450 | nritems = btrfs_header_nritems(leaf); |
3451 | data_end = leaf_data_end(root, leaf); |
3452 | |
3453 | if (btrfs_leaf_free_space(root, leaf) < total_size) { |
3454 | for (i = nr; i >= 0; i--) { |
3455 | total_data -= data_size[i]; |
3456 | total_size -= data_size[i] + sizeof(struct btrfs_item); |
3457 | if (total_size < btrfs_leaf_free_space(root, leaf)) |
3458 | break; |
3459 | } |
3460 | nr = i; |
3461 | } |
3462 | |
3463 | slot = path->slots[0]; |
3464 | BUG_ON(slot < 0); |
3465 | |
3466 | if (slot != nritems) { |
3467 | unsigned int old_data = btrfs_item_end_nr(leaf, slot); |
3468 | |
3469 | item = btrfs_item_nr(leaf, slot); |
3470 | btrfs_item_key_to_cpu(leaf, &found_key, slot); |
3471 | |
3472 | /* figure out how many keys we can insert in here */ |
3473 | total_data = data_size[0]; |
3474 | for (i = 1; i < nr; i++) { |
3475 | if (btrfs_comp_cpu_keys(&found_key, cpu_key + i) <= 0) |
3476 | break; |
3477 | total_data += data_size[i]; |
3478 | } |
3479 | nr = i; |
3480 | |
3481 | if (old_data < data_end) { |
3482 | btrfs_print_leaf(root, leaf); |
3483 | printk(KERN_CRIT "slot %d old_data %d data_end %d\n", |
3484 | slot, old_data, data_end); |
3485 | BUG_ON(1); |
3486 | } |
3487 | /* |
3488 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
3489 | */ |
3490 | /* first correct the data pointers */ |
3491 | WARN_ON(leaf->map_token); |
3492 | for (i = slot; i < nritems; i++) { |
3493 | u32 ioff; |
3494 | |
3495 | item = btrfs_item_nr(leaf, i); |
3496 | if (!leaf->map_token) { |
3497 | map_extent_buffer(leaf, (unsigned long)item, |
3498 | sizeof(struct btrfs_item), |
3499 | &leaf->map_token, &leaf->kaddr, |
3500 | &leaf->map_start, &leaf->map_len, |
3501 | KM_USER1); |
3502 | } |
3503 | |
3504 | ioff = btrfs_item_offset(leaf, item); |
3505 | btrfs_set_item_offset(leaf, item, ioff - total_data); |
3506 | } |
3507 | if (leaf->map_token) { |
3508 | unmap_extent_buffer(leaf, leaf->map_token, KM_USER1); |
3509 | leaf->map_token = NULL; |
3510 | } |
3511 | |
3512 | /* shift the items */ |
3513 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr), |
3514 | btrfs_item_nr_offset(slot), |
3515 | (nritems - slot) * sizeof(struct btrfs_item)); |
3516 | |
3517 | /* shift the data */ |
3518 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
3519 | data_end - total_data, btrfs_leaf_data(leaf) + |
3520 | data_end, old_data - data_end); |
3521 | data_end = old_data; |
3522 | } else { |
3523 | /* |
3524 | * this sucks but it has to be done, if we are inserting at |
3525 | * the end of the leaf only insert 1 of the items, since we |
3526 | * have no way of knowing whats on the next leaf and we'd have |
3527 | * to drop our current locks to figure it out |
3528 | */ |
3529 | nr = 1; |
3530 | } |
3531 | |
3532 | /* setup the item for the new data */ |
3533 | for (i = 0; i < nr; i++) { |
3534 | btrfs_cpu_key_to_disk(&disk_key, cpu_key + i); |
3535 | btrfs_set_item_key(leaf, &disk_key, slot + i); |
3536 | item = btrfs_item_nr(leaf, slot + i); |
3537 | btrfs_set_item_offset(leaf, item, data_end - data_size[i]); |
3538 | data_end -= data_size[i]; |
3539 | btrfs_set_item_size(leaf, item, data_size[i]); |
3540 | } |
3541 | btrfs_set_header_nritems(leaf, nritems + nr); |
3542 | btrfs_mark_buffer_dirty(leaf); |
3543 | |
3544 | ret = 0; |
3545 | if (slot == 0) { |
3546 | btrfs_cpu_key_to_disk(&disk_key, cpu_key); |
3547 | ret = fixup_low_keys(trans, root, path, &disk_key, 1); |
3548 | } |
3549 | |
3550 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
3551 | btrfs_print_leaf(root, leaf); |
3552 | BUG(); |
3553 | } |
3554 | out: |
3555 | if (!ret) |
3556 | ret = nr; |
3557 | return ret; |
3558 | } |
3559 | |
3560 | /* |
3561 | * this is a helper for btrfs_insert_empty_items, the main goal here is |
3562 | * to save stack depth by doing the bulk of the work in a function |
3563 | * that doesn't call btrfs_search_slot |
3564 | */ |
3565 | static noinline_for_stack int |
3566 | setup_items_for_insert(struct btrfs_trans_handle *trans, |
3567 | struct btrfs_root *root, struct btrfs_path *path, |
3568 | struct btrfs_key *cpu_key, u32 *data_size, |
3569 | u32 total_data, u32 total_size, int nr) |
3570 | { |
3571 | struct btrfs_item *item; |
3572 | int i; |
3573 | u32 nritems; |
3574 | unsigned int data_end; |
3575 | struct btrfs_disk_key disk_key; |
3576 | int ret; |
3577 | struct extent_buffer *leaf; |
3578 | int slot; |
3579 | |
3580 | leaf = path->nodes[0]; |
3581 | slot = path->slots[0]; |
3582 | |
3583 | nritems = btrfs_header_nritems(leaf); |
3584 | data_end = leaf_data_end(root, leaf); |
3585 | |
3586 | if (btrfs_leaf_free_space(root, leaf) < total_size) { |
3587 | btrfs_print_leaf(root, leaf); |
3588 | printk(KERN_CRIT "not enough freespace need %u have %d\n", |
3589 | total_size, btrfs_leaf_free_space(root, leaf)); |
3590 | BUG(); |
3591 | } |
3592 | |
3593 | if (slot != nritems) { |
3594 | unsigned int old_data = btrfs_item_end_nr(leaf, slot); |
3595 | |
3596 | if (old_data < data_end) { |
3597 | btrfs_print_leaf(root, leaf); |
3598 | printk(KERN_CRIT "slot %d old_data %d data_end %d\n", |
3599 | slot, old_data, data_end); |
3600 | BUG_ON(1); |
3601 | } |
3602 | /* |
3603 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
3604 | */ |
3605 | /* first correct the data pointers */ |
3606 | WARN_ON(leaf->map_token); |
3607 | for (i = slot; i < nritems; i++) { |
3608 | u32 ioff; |
3609 | |
3610 | item = btrfs_item_nr(leaf, i); |
3611 | if (!leaf->map_token) { |
3612 | map_extent_buffer(leaf, (unsigned long)item, |
3613 | sizeof(struct btrfs_item), |
3614 | &leaf->map_token, &leaf->kaddr, |
3615 | &leaf->map_start, &leaf->map_len, |
3616 | KM_USER1); |
3617 | } |
3618 | |
3619 | ioff = btrfs_item_offset(leaf, item); |
3620 | btrfs_set_item_offset(leaf, item, ioff - total_data); |
3621 | } |
3622 | if (leaf->map_token) { |
3623 | unmap_extent_buffer(leaf, leaf->map_token, KM_USER1); |
3624 | leaf->map_token = NULL; |
3625 | } |
3626 | |
3627 | /* shift the items */ |
3628 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr), |
3629 | btrfs_item_nr_offset(slot), |
3630 | (nritems - slot) * sizeof(struct btrfs_item)); |
3631 | |
3632 | /* shift the data */ |
3633 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
3634 | data_end - total_data, btrfs_leaf_data(leaf) + |
3635 | data_end, old_data - data_end); |
3636 | data_end = old_data; |
3637 | } |
3638 | |
3639 | /* setup the item for the new data */ |
3640 | for (i = 0; i < nr; i++) { |
3641 | btrfs_cpu_key_to_disk(&disk_key, cpu_key + i); |
3642 | btrfs_set_item_key(leaf, &disk_key, slot + i); |
3643 | item = btrfs_item_nr(leaf, slot + i); |
3644 | btrfs_set_item_offset(leaf, item, data_end - data_size[i]); |
3645 | data_end -= data_size[i]; |
3646 | btrfs_set_item_size(leaf, item, data_size[i]); |
3647 | } |
3648 | |
3649 | btrfs_set_header_nritems(leaf, nritems + nr); |
3650 | |
3651 | ret = 0; |
3652 | if (slot == 0) { |
3653 | struct btrfs_disk_key disk_key; |
3654 | btrfs_cpu_key_to_disk(&disk_key, cpu_key); |
3655 | ret = fixup_low_keys(trans, root, path, &disk_key, 1); |
3656 | } |
3657 | btrfs_unlock_up_safe(path, 1); |
3658 | btrfs_mark_buffer_dirty(leaf); |
3659 | |
3660 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
3661 | btrfs_print_leaf(root, leaf); |
3662 | BUG(); |
3663 | } |
3664 | return ret; |
3665 | } |
3666 | |
3667 | /* |
3668 | * Given a key and some data, insert items into the tree. |
3669 | * This does all the path init required, making room in the tree if needed. |
3670 | */ |
3671 | int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, |
3672 | struct btrfs_root *root, |
3673 | struct btrfs_path *path, |
3674 | struct btrfs_key *cpu_key, u32 *data_size, |
3675 | int nr) |
3676 | { |
3677 | struct extent_buffer *leaf; |
3678 | int ret = 0; |
3679 | int slot; |
3680 | int i; |
3681 | u32 total_size = 0; |
3682 | u32 total_data = 0; |
3683 | |
3684 | for (i = 0; i < nr; i++) |
3685 | total_data += data_size[i]; |
3686 | |
3687 | total_size = total_data + (nr * sizeof(struct btrfs_item)); |
3688 | ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1); |
3689 | if (ret == 0) |
3690 | return -EEXIST; |
3691 | if (ret < 0) |
3692 | goto out; |
3693 | |
3694 | leaf = path->nodes[0]; |
3695 | slot = path->slots[0]; |
3696 | BUG_ON(slot < 0); |
3697 | |
3698 | ret = setup_items_for_insert(trans, root, path, cpu_key, data_size, |
3699 | total_data, total_size, nr); |
3700 | |
3701 | out: |
3702 | return ret; |
3703 | } |
3704 | |
3705 | /* |
3706 | * Given a key and some data, insert an item into the tree. |
3707 | * This does all the path init required, making room in the tree if needed. |
3708 | */ |
3709 | int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root |
3710 | *root, struct btrfs_key *cpu_key, void *data, u32 |
3711 | data_size) |
3712 | { |
3713 | int ret = 0; |
3714 | struct btrfs_path *path; |
3715 | struct extent_buffer *leaf; |
3716 | unsigned long ptr; |
3717 | |
3718 | path = btrfs_alloc_path(); |
3719 | BUG_ON(!path); |
3720 | ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); |
3721 | if (!ret) { |
3722 | leaf = path->nodes[0]; |
3723 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
3724 | write_extent_buffer(leaf, data, ptr, data_size); |
3725 | btrfs_mark_buffer_dirty(leaf); |
3726 | } |
3727 | btrfs_free_path(path); |
3728 | return ret; |
3729 | } |
3730 | |
3731 | /* |
3732 | * delete the pointer from a given node. |
3733 | * |
3734 | * the tree should have been previously balanced so the deletion does not |
3735 | * empty a node. |
3736 | */ |
3737 | static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
3738 | struct btrfs_path *path, int level, int slot) |
3739 | { |
3740 | struct extent_buffer *parent = path->nodes[level]; |
3741 | u32 nritems; |
3742 | int ret = 0; |
3743 | int wret; |
3744 | |
3745 | nritems = btrfs_header_nritems(parent); |
3746 | if (slot != nritems - 1) { |
3747 | memmove_extent_buffer(parent, |
3748 | btrfs_node_key_ptr_offset(slot), |
3749 | btrfs_node_key_ptr_offset(slot + 1), |
3750 | sizeof(struct btrfs_key_ptr) * |
3751 | (nritems - slot - 1)); |
3752 | } |
3753 | nritems--; |
3754 | btrfs_set_header_nritems(parent, nritems); |
3755 | if (nritems == 0 && parent == root->node) { |
3756 | BUG_ON(btrfs_header_level(root->node) != 1); |
3757 | /* just turn the root into a leaf and break */ |
3758 | btrfs_set_header_level(root->node, 0); |
3759 | } else if (slot == 0) { |
3760 | struct btrfs_disk_key disk_key; |
3761 | |
3762 | btrfs_node_key(parent, &disk_key, 0); |
3763 | wret = fixup_low_keys(trans, root, path, &disk_key, level + 1); |
3764 | if (wret) |
3765 | ret = wret; |
3766 | } |
3767 | btrfs_mark_buffer_dirty(parent); |
3768 | return ret; |
3769 | } |
3770 | |
3771 | /* |
3772 | * a helper function to delete the leaf pointed to by path->slots[1] and |
3773 | * path->nodes[1]. |
3774 | * |
3775 | * This deletes the pointer in path->nodes[1] and frees the leaf |
3776 | * block extent. zero is returned if it all worked out, < 0 otherwise. |
3777 | * |
3778 | * The path must have already been setup for deleting the leaf, including |
3779 | * all the proper balancing. path->nodes[1] must be locked. |
3780 | */ |
3781 | static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans, |
3782 | struct btrfs_root *root, |
3783 | struct btrfs_path *path, |
3784 | struct extent_buffer *leaf) |
3785 | { |
3786 | int ret; |
3787 | |
3788 | WARN_ON(btrfs_header_generation(leaf) != trans->transid); |
3789 | ret = del_ptr(trans, root, path, 1, path->slots[1]); |
3790 | if (ret) |
3791 | return ret; |
3792 | |
3793 | /* |
3794 | * btrfs_free_extent is expensive, we want to make sure we |
3795 | * aren't holding any locks when we call it |
3796 | */ |
3797 | btrfs_unlock_up_safe(path, 0); |
3798 | |
3799 | ret = btrfs_free_tree_block(trans, root, leaf->start, leaf->len, |
3800 | 0, root->root_key.objectid, 0); |
3801 | return ret; |
3802 | } |
3803 | /* |
3804 | * delete the item at the leaf level in path. If that empties |
3805 | * the leaf, remove it from the tree |
3806 | */ |
3807 | int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
3808 | struct btrfs_path *path, int slot, int nr) |
3809 | { |
3810 | struct extent_buffer *leaf; |
3811 | struct btrfs_item *item; |
3812 | int last_off; |
3813 | int dsize = 0; |
3814 | int ret = 0; |
3815 | int wret; |
3816 | int i; |
3817 | u32 nritems; |
3818 | |
3819 | leaf = path->nodes[0]; |
3820 | last_off = btrfs_item_offset_nr(leaf, slot + nr - 1); |
3821 | |
3822 | for (i = 0; i < nr; i++) |
3823 | dsize += btrfs_item_size_nr(leaf, slot + i); |
3824 | |
3825 | nritems = btrfs_header_nritems(leaf); |
3826 | |
3827 | if (slot + nr != nritems) { |
3828 | int data_end = leaf_data_end(root, leaf); |
3829 | |
3830 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
3831 | data_end + dsize, |
3832 | btrfs_leaf_data(leaf) + data_end, |
3833 | last_off - data_end); |
3834 | |
3835 | for (i = slot + nr; i < nritems; i++) { |
3836 | u32 ioff; |
3837 | |
3838 | item = btrfs_item_nr(leaf, i); |
3839 | if (!leaf->map_token) { |
3840 | map_extent_buffer(leaf, (unsigned long)item, |
3841 | sizeof(struct btrfs_item), |
3842 | &leaf->map_token, &leaf->kaddr, |
3843 | &leaf->map_start, &leaf->map_len, |
3844 | KM_USER1); |
3845 | } |
3846 | ioff = btrfs_item_offset(leaf, item); |
3847 | btrfs_set_item_offset(leaf, item, ioff + dsize); |
3848 | } |
3849 | |
3850 | if (leaf->map_token) { |
3851 | unmap_extent_buffer(leaf, leaf->map_token, KM_USER1); |
3852 | leaf->map_token = NULL; |
3853 | } |
3854 | |
3855 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot), |
3856 | btrfs_item_nr_offset(slot + nr), |
3857 | sizeof(struct btrfs_item) * |
3858 | (nritems - slot - nr)); |
3859 | } |
3860 | btrfs_set_header_nritems(leaf, nritems - nr); |
3861 | nritems -= nr; |
3862 | |
3863 | /* delete the leaf if we've emptied it */ |
3864 | if (nritems == 0) { |
3865 | if (leaf == root->node) { |
3866 | btrfs_set_header_level(leaf, 0); |
3867 | } else { |
3868 | ret = btrfs_del_leaf(trans, root, path, leaf); |
3869 | BUG_ON(ret); |
3870 | } |
3871 | } else { |
3872 | int used = leaf_space_used(leaf, 0, nritems); |
3873 | if (slot == 0) { |
3874 | struct btrfs_disk_key disk_key; |
3875 | |
3876 | btrfs_item_key(leaf, &disk_key, 0); |
3877 | wret = fixup_low_keys(trans, root, path, |
3878 | &disk_key, 1); |
3879 | if (wret) |
3880 | ret = wret; |
3881 | } |
3882 | |
3883 | /* delete the leaf if it is mostly empty */ |
3884 | if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) { |
3885 | /* push_leaf_left fixes the path. |
3886 | * make sure the path still points to our leaf |
3887 | * for possible call to del_ptr below |
3888 | */ |
3889 | slot = path->slots[1]; |
3890 | extent_buffer_get(leaf); |
3891 | |
3892 | btrfs_set_path_blocking(path); |
3893 | wret = push_leaf_left(trans, root, path, 1, 1); |
3894 | if (wret < 0 && wret != -ENOSPC) |
3895 | ret = wret; |
3896 | |
3897 | if (path->nodes[0] == leaf && |
3898 | btrfs_header_nritems(leaf)) { |
3899 | wret = push_leaf_right(trans, root, path, 1, 1); |
3900 | if (wret < 0 && wret != -ENOSPC) |
3901 | ret = wret; |
3902 | } |
3903 | |
3904 | if (btrfs_header_nritems(leaf) == 0) { |
3905 | path->slots[1] = slot; |
3906 | ret = btrfs_del_leaf(trans, root, path, leaf); |
3907 | BUG_ON(ret); |
3908 | free_extent_buffer(leaf); |
3909 | } else { |
3910 | /* if we're still in the path, make sure |
3911 | * we're dirty. Otherwise, one of the |
3912 | * push_leaf functions must have already |
3913 | * dirtied this buffer |
3914 | */ |
3915 | if (path->nodes[0] == leaf) |
3916 | btrfs_mark_buffer_dirty(leaf); |
3917 | free_extent_buffer(leaf); |
3918 | } |
3919 | } else { |
3920 | btrfs_mark_buffer_dirty(leaf); |
3921 | } |
3922 | } |
3923 | return ret; |
3924 | } |
3925 | |
3926 | /* |
3927 | * search the tree again to find a leaf with lesser keys |
3928 | * returns 0 if it found something or 1 if there are no lesser leaves. |
3929 | * returns < 0 on io errors. |
3930 | * |
3931 | * This may release the path, and so you may lose any locks held at the |
3932 | * time you call it. |
3933 | */ |
3934 | int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) |
3935 | { |
3936 | struct btrfs_key key; |
3937 | struct btrfs_disk_key found_key; |
3938 | int ret; |
3939 | |
3940 | btrfs_item_key_to_cpu(path->nodes[0], &key, 0); |
3941 | |
3942 | if (key.offset > 0) |
3943 | key.offset--; |
3944 | else if (key.type > 0) |
3945 | key.type--; |
3946 | else if (key.objectid > 0) |
3947 | key.objectid--; |
3948 | else |
3949 | return 1; |
3950 | |
3951 | btrfs_release_path(root, path); |
3952 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
3953 | if (ret < 0) |
3954 | return ret; |
3955 | btrfs_item_key(path->nodes[0], &found_key, 0); |
3956 | ret = comp_keys(&found_key, &key); |
3957 | if (ret < 0) |
3958 | return 0; |
3959 | return 1; |
3960 | } |
3961 | |
3962 | /* |
3963 | * A helper function to walk down the tree starting at min_key, and looking |
3964 | * for nodes or leaves that are either in cache or have a minimum |
3965 | * transaction id. This is used by the btree defrag code, and tree logging |
3966 | * |
3967 | * This does not cow, but it does stuff the starting key it finds back |
3968 | * into min_key, so you can call btrfs_search_slot with cow=1 on the |
3969 | * key and get a writable path. |
3970 | * |
3971 | * This does lock as it descends, and path->keep_locks should be set |
3972 | * to 1 by the caller. |
3973 | * |
3974 | * This honors path->lowest_level to prevent descent past a given level |
3975 | * of the tree. |
3976 | * |
3977 | * min_trans indicates the oldest transaction that you are interested |
3978 | * in walking through. Any nodes or leaves older than min_trans are |
3979 | * skipped over (without reading them). |
3980 | * |
3981 | * returns zero if something useful was found, < 0 on error and 1 if there |
3982 | * was nothing in the tree that matched the search criteria. |
3983 | */ |
3984 | int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, |
3985 | struct btrfs_key *max_key, |
3986 | struct btrfs_path *path, int cache_only, |
3987 | u64 min_trans) |
3988 | { |
3989 | struct extent_buffer *cur; |
3990 | struct btrfs_key found_key; |
3991 | int slot; |
3992 | int sret; |
3993 | u32 nritems; |
3994 | int level; |
3995 | int ret = 1; |
3996 | |
3997 | WARN_ON(!path->keep_locks); |
3998 | again: |
3999 | cur = btrfs_lock_root_node(root); |
4000 | level = btrfs_header_level(cur); |
4001 | WARN_ON(path->nodes[level]); |
4002 | path->nodes[level] = cur; |
4003 | path->locks[level] = 1; |
4004 | |
4005 | if (btrfs_header_generation(cur) < min_trans) { |
4006 | ret = 1; |
4007 | goto out; |
4008 | } |
4009 | while (1) { |
4010 | nritems = btrfs_header_nritems(cur); |
4011 | level = btrfs_header_level(cur); |
4012 | sret = bin_search(cur, min_key, level, &slot); |
4013 | |
4014 | /* at the lowest level, we're done, setup the path and exit */ |
4015 | if (level == path->lowest_level) { |
4016 | if (slot >= nritems) |
4017 | goto find_next_key; |
4018 | ret = 0; |
4019 | path->slots[level] = slot; |
4020 | btrfs_item_key_to_cpu(cur, &found_key, slot); |
4021 | goto out; |
4022 | } |
4023 | if (sret && slot > 0) |
4024 | slot--; |
4025 | /* |
4026 | * check this node pointer against the cache_only and |
4027 | * min_trans parameters. If it isn't in cache or is too |
4028 | * old, skip to the next one. |
4029 | */ |
4030 | while (slot < nritems) { |
4031 | u64 blockptr; |
4032 | u64 gen; |
4033 | struct extent_buffer *tmp; |
4034 | struct btrfs_disk_key disk_key; |
4035 | |
4036 | blockptr = btrfs_node_blockptr(cur, slot); |
4037 | gen = btrfs_node_ptr_generation(cur, slot); |
4038 | if (gen < min_trans) { |
4039 | slot++; |
4040 | continue; |
4041 | } |
4042 | if (!cache_only) |
4043 | break; |
4044 | |
4045 | if (max_key) { |
4046 | btrfs_node_key(cur, &disk_key, slot); |
4047 | if (comp_keys(&disk_key, max_key) >= 0) { |
4048 | ret = 1; |
4049 | goto out; |
4050 | } |
4051 | } |
4052 | |
4053 | tmp = btrfs_find_tree_block(root, blockptr, |
4054 | btrfs_level_size(root, level - 1)); |
4055 | |
4056 | if (tmp && btrfs_buffer_uptodate(tmp, gen)) { |
4057 | free_extent_buffer(tmp); |
4058 | break; |
4059 | } |
4060 | if (tmp) |
4061 | free_extent_buffer(tmp); |
4062 | slot++; |
4063 | } |
4064 | find_next_key: |
4065 | /* |
4066 | * we didn't find a candidate key in this node, walk forward |
4067 | * and find another one |
4068 | */ |
4069 | if (slot >= nritems) { |
4070 | path->slots[level] = slot; |
4071 | btrfs_set_path_blocking(path); |
4072 | sret = btrfs_find_next_key(root, path, min_key, level, |
4073 | cache_only, min_trans); |
4074 | if (sret == 0) { |
4075 | btrfs_release_path(root, path); |
4076 | goto again; |
4077 | } else { |
4078 | goto out; |
4079 | } |
4080 | } |
4081 | /* save our key for returning back */ |
4082 | btrfs_node_key_to_cpu(cur, &found_key, slot); |
4083 | path->slots[level] = slot; |
4084 | if (level == path->lowest_level) { |
4085 | ret = 0; |
4086 | unlock_up(path, level, 1); |
4087 | goto out; |
4088 | } |
4089 | btrfs_set_path_blocking(path); |
4090 | cur = read_node_slot(root, cur, slot); |
4091 | |
4092 | btrfs_tree_lock(cur); |
4093 | |
4094 | path->locks[level - 1] = 1; |
4095 | path->nodes[level - 1] = cur; |
4096 | unlock_up(path, level, 1); |
4097 | btrfs_clear_path_blocking(path, NULL); |
4098 | } |
4099 | out: |
4100 | if (ret == 0) |
4101 | memcpy(min_key, &found_key, sizeof(found_key)); |
4102 | btrfs_set_path_blocking(path); |
4103 | return ret; |
4104 | } |
4105 | |
4106 | /* |
4107 | * this is similar to btrfs_next_leaf, but does not try to preserve |
4108 | * and fixup the path. It looks for and returns the next key in the |
4109 | * tree based on the current path and the cache_only and min_trans |
4110 | * parameters. |
4111 | * |
4112 | * 0 is returned if another key is found, < 0 if there are any errors |
4113 | * and 1 is returned if there are no higher keys in the tree |
4114 | * |
4115 | * path->keep_locks should be set to 1 on the search made before |
4116 | * calling this function. |
4117 | */ |
4118 | int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, |
4119 | struct btrfs_key *key, int level, |
4120 | int cache_only, u64 min_trans) |
4121 | { |
4122 | int slot; |
4123 | struct extent_buffer *c; |
4124 | |
4125 | WARN_ON(!path->keep_locks); |
4126 | while (level < BTRFS_MAX_LEVEL) { |
4127 | if (!path->nodes[level]) |
4128 | return 1; |
4129 | |
4130 | slot = path->slots[level] + 1; |
4131 | c = path->nodes[level]; |
4132 | next: |
4133 | if (slot >= btrfs_header_nritems(c)) { |
4134 | int ret; |
4135 | int orig_lowest; |
4136 | struct btrfs_key cur_key; |
4137 | if (level + 1 >= BTRFS_MAX_LEVEL || |
4138 | !path->nodes[level + 1]) |
4139 | return 1; |
4140 | |
4141 | if (path->locks[level + 1]) { |
4142 | level++; |
4143 | continue; |
4144 | } |
4145 | |
4146 | slot = btrfs_header_nritems(c) - 1; |
4147 | if (level == 0) |
4148 | btrfs_item_key_to_cpu(c, &cur_key, slot); |
4149 | else |
4150 | btrfs_node_key_to_cpu(c, &cur_key, slot); |
4151 | |
4152 | orig_lowest = path->lowest_level; |
4153 | btrfs_release_path(root, path); |
4154 | path->lowest_level = level; |
4155 | ret = btrfs_search_slot(NULL, root, &cur_key, path, |
4156 | 0, 0); |
4157 | path->lowest_level = orig_lowest; |
4158 | if (ret < 0) |
4159 | return ret; |
4160 | |
4161 | c = path->nodes[level]; |
4162 | slot = path->slots[level]; |
4163 | if (ret == 0) |
4164 | slot++; |
4165 | goto next; |
4166 | } |
4167 | |
4168 | if (level == 0) |
4169 | btrfs_item_key_to_cpu(c, key, slot); |
4170 | else { |
4171 | u64 blockptr = btrfs_node_blockptr(c, slot); |
4172 | u64 gen = btrfs_node_ptr_generation(c, slot); |
4173 | |
4174 | if (cache_only) { |
4175 | struct extent_buffer *cur; |
4176 | cur = btrfs_find_tree_block(root, blockptr, |
4177 | btrfs_level_size(root, level - 1)); |
4178 | if (!cur || !btrfs_buffer_uptodate(cur, gen)) { |
4179 | slot++; |
4180 | if (cur) |
4181 | free_extent_buffer(cur); |
4182 | goto next; |
4183 | } |
4184 | free_extent_buffer(cur); |
4185 | } |
4186 | if (gen < min_trans) { |
4187 | slot++; |
4188 | goto next; |
4189 | } |
4190 | btrfs_node_key_to_cpu(c, key, slot); |
4191 | } |
4192 | return 0; |
4193 | } |
4194 | return 1; |
4195 | } |
4196 | |
4197 | /* |
4198 | * search the tree again to find a leaf with greater keys |
4199 | * returns 0 if it found something or 1 if there are no greater leaves. |
4200 | * returns < 0 on io errors. |
4201 | */ |
4202 | int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) |
4203 | { |
4204 | int slot; |
4205 | int level; |
4206 | struct extent_buffer *c; |
4207 | struct extent_buffer *next; |
4208 | struct btrfs_key key; |
4209 | u32 nritems; |
4210 | int ret; |
4211 | int old_spinning = path->leave_spinning; |
4212 | int force_blocking = 0; |
4213 | |
4214 | nritems = btrfs_header_nritems(path->nodes[0]); |
4215 | if (nritems == 0) |
4216 | return 1; |
4217 | |
4218 | /* |
4219 | * we take the blocks in an order that upsets lockdep. Using |
4220 | * blocking mode is the only way around it. |
4221 | */ |
4222 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
4223 | force_blocking = 1; |
4224 | #endif |
4225 | |
4226 | btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1); |
4227 | again: |
4228 | level = 1; |
4229 | next = NULL; |
4230 | btrfs_release_path(root, path); |
4231 | |
4232 | path->keep_locks = 1; |
4233 | |
4234 | if (!force_blocking) |
4235 | path->leave_spinning = 1; |
4236 | |
4237 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
4238 | path->keep_locks = 0; |
4239 | |
4240 | if (ret < 0) |
4241 | return ret; |
4242 | |
4243 | nritems = btrfs_header_nritems(path->nodes[0]); |
4244 | /* |
4245 | * by releasing the path above we dropped all our locks. A balance |
4246 | * could have added more items next to the key that used to be |
4247 | * at the very end of the block. So, check again here and |
4248 | * advance the path if there are now more items available. |
4249 | */ |
4250 | if (nritems > 0 && path->slots[0] < nritems - 1) { |
4251 | if (ret == 0) |
4252 | path->slots[0]++; |
4253 | ret = 0; |
4254 | goto done; |
4255 | } |
4256 | |
4257 | while (level < BTRFS_MAX_LEVEL) { |
4258 | if (!path->nodes[level]) { |
4259 | ret = 1; |
4260 | goto done; |
4261 | } |
4262 | |
4263 | slot = path->slots[level] + 1; |
4264 | c = path->nodes[level]; |
4265 | if (slot >= btrfs_header_nritems(c)) { |
4266 | level++; |
4267 | if (level == BTRFS_MAX_LEVEL) { |
4268 | ret = 1; |
4269 | goto done; |
4270 | } |
4271 | continue; |
4272 | } |
4273 | |
4274 | if (next) { |
4275 | btrfs_tree_unlock(next); |
4276 | free_extent_buffer(next); |
4277 | } |
4278 | |
4279 | next = c; |
4280 | ret = read_block_for_search(NULL, root, path, &next, level, |
4281 | slot, &key); |
4282 | if (ret == -EAGAIN) |
4283 | goto again; |
4284 | |
4285 | if (ret < 0) { |
4286 | btrfs_release_path(root, path); |
4287 | goto done; |
4288 | } |
4289 | |
4290 | if (!path->skip_locking) { |
4291 | ret = btrfs_try_spin_lock(next); |
4292 | if (!ret) { |
4293 | btrfs_set_path_blocking(path); |
4294 | btrfs_tree_lock(next); |
4295 | if (!force_blocking) |
4296 | btrfs_clear_path_blocking(path, next); |
4297 | } |
4298 | if (force_blocking) |
4299 | btrfs_set_lock_blocking(next); |
4300 | } |
4301 | break; |
4302 | } |
4303 | path->slots[level] = slot; |
4304 | while (1) { |
4305 | level--; |
4306 | c = path->nodes[level]; |
4307 | if (path->locks[level]) |
4308 | btrfs_tree_unlock(c); |
4309 | |
4310 | free_extent_buffer(c); |
4311 | path->nodes[level] = next; |
4312 | path->slots[level] = 0; |
4313 | if (!path->skip_locking) |
4314 | path->locks[level] = 1; |
4315 | |
4316 | if (!level) |
4317 | break; |
4318 | |
4319 | ret = read_block_for_search(NULL, root, path, &next, level, |
4320 | 0, &key); |
4321 | if (ret == -EAGAIN) |
4322 | goto again; |
4323 | |
4324 | if (ret < 0) { |
4325 | btrfs_release_path(root, path); |
4326 | goto done; |
4327 | } |
4328 | |
4329 | if (!path->skip_locking) { |
4330 | btrfs_assert_tree_locked(path->nodes[level]); |
4331 | ret = btrfs_try_spin_lock(next); |
4332 | if (!ret) { |
4333 | btrfs_set_path_blocking(path); |
4334 | btrfs_tree_lock(next); |
4335 | if (!force_blocking) |
4336 | btrfs_clear_path_blocking(path, next); |
4337 | } |
4338 | if (force_blocking) |
4339 | btrfs_set_lock_blocking(next); |
4340 | } |
4341 | } |
4342 | ret = 0; |
4343 | done: |
4344 | unlock_up(path, 0, 1); |
4345 | path->leave_spinning = old_spinning; |
4346 | if (!old_spinning) |
4347 | btrfs_set_path_blocking(path); |
4348 | |
4349 | return ret; |
4350 | } |
4351 | |
4352 | /* |
4353 | * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps |
4354 | * searching until it gets past min_objectid or finds an item of 'type' |
4355 | * |
4356 | * returns 0 if something is found, 1 if nothing was found and < 0 on error |
4357 | */ |
4358 | int btrfs_previous_item(struct btrfs_root *root, |
4359 | struct btrfs_path *path, u64 min_objectid, |
4360 | int type) |
4361 | { |
4362 | struct btrfs_key found_key; |
4363 | struct extent_buffer *leaf; |
4364 | u32 nritems; |
4365 | int ret; |
4366 | |
4367 | while (1) { |
4368 | if (path->slots[0] == 0) { |
4369 | btrfs_set_path_blocking(path); |
4370 | ret = btrfs_prev_leaf(root, path); |
4371 | if (ret != 0) |
4372 | return ret; |
4373 | } else { |
4374 | path->slots[0]--; |
4375 | } |
4376 | leaf = path->nodes[0]; |
4377 | nritems = btrfs_header_nritems(leaf); |
4378 | if (nritems == 0) |
4379 | return 1; |
4380 | if (path->slots[0] == nritems) |
4381 | path->slots[0]--; |
4382 | |
4383 | btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); |
4384 | if (found_key.objectid < min_objectid) |
4385 | break; |
4386 | if (found_key.type == type) |
4387 | return 0; |
4388 | if (found_key.objectid == min_objectid && |
4389 | found_key.type < type) |
4390 | break; |
4391 | } |
4392 | return 1; |
4393 | } |
4394 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9