Commit | Line | Data |
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6cbd5570 CM |
1 | /* |
2 | * Copyright (C) 2007 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 | ||
581bb050 LZ |
19 | #include <linux/delay.h> |
20 | #include <linux/kthread.h> | |
21 | #include <linux/pagemap.h> | |
22 | ||
9f5fae2f CM |
23 | #include "ctree.h" |
24 | #include "disk-io.h" | |
581bb050 LZ |
25 | #include "free-space-cache.h" |
26 | #include "inode-map.h" | |
9f5fae2f CM |
27 | #include "transaction.h" |
28 | ||
581bb050 LZ |
29 | static int caching_kthread(void *data) |
30 | { | |
31 | struct btrfs_root *root = data; | |
32 | struct btrfs_fs_info *fs_info = root->fs_info; | |
33 | struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; | |
34 | struct btrfs_key key; | |
35 | struct btrfs_path *path; | |
36 | struct extent_buffer *leaf; | |
37 | u64 last = (u64)-1; | |
38 | int slot; | |
39 | int ret; | |
40 | ||
4b9465cb CM |
41 | if (!btrfs_test_opt(root, INODE_MAP_CACHE)) |
42 | return 0; | |
43 | ||
581bb050 LZ |
44 | path = btrfs_alloc_path(); |
45 | if (!path) | |
46 | return -ENOMEM; | |
47 | ||
48 | /* Since the commit root is read-only, we can safely skip locking. */ | |
49 | path->skip_locking = 1; | |
50 | path->search_commit_root = 1; | |
51 | path->reada = 2; | |
52 | ||
53 | key.objectid = BTRFS_FIRST_FREE_OBJECTID; | |
54 | key.offset = 0; | |
55 | key.type = BTRFS_INODE_ITEM_KEY; | |
56 | again: | |
57 | /* need to make sure the commit_root doesn't disappear */ | |
9e351cc8 | 58 | down_read(&fs_info->commit_root_sem); |
581bb050 LZ |
59 | |
60 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); | |
61 | if (ret < 0) | |
62 | goto out; | |
63 | ||
64 | while (1) { | |
7841cb28 | 65 | if (btrfs_fs_closing(fs_info)) |
581bb050 LZ |
66 | goto out; |
67 | ||
68 | leaf = path->nodes[0]; | |
69 | slot = path->slots[0]; | |
a47d6b70 | 70 | if (slot >= btrfs_header_nritems(leaf)) { |
581bb050 LZ |
71 | ret = btrfs_next_leaf(root, path); |
72 | if (ret < 0) | |
73 | goto out; | |
74 | else if (ret > 0) | |
75 | break; | |
76 | ||
77 | if (need_resched() || | |
78 | btrfs_transaction_in_commit(fs_info)) { | |
79 | leaf = path->nodes[0]; | |
80 | ||
fae7f21c | 81 | if (WARN_ON(btrfs_header_nritems(leaf) == 0)) |
581bb050 | 82 | break; |
581bb050 LZ |
83 | |
84 | /* | |
85 | * Save the key so we can advances forward | |
86 | * in the next search. | |
87 | */ | |
88 | btrfs_item_key_to_cpu(leaf, &key, 0); | |
945d8962 | 89 | btrfs_release_path(path); |
581bb050 | 90 | root->cache_progress = last; |
9e351cc8 | 91 | up_read(&fs_info->commit_root_sem); |
581bb050 LZ |
92 | schedule_timeout(1); |
93 | goto again; | |
94 | } else | |
95 | continue; | |
96 | } | |
97 | ||
98 | btrfs_item_key_to_cpu(leaf, &key, slot); | |
99 | ||
100 | if (key.type != BTRFS_INODE_ITEM_KEY) | |
101 | goto next; | |
102 | ||
a47d6b70 | 103 | if (key.objectid >= root->highest_objectid) |
581bb050 LZ |
104 | break; |
105 | ||
106 | if (last != (u64)-1 && last + 1 != key.objectid) { | |
107 | __btrfs_add_free_space(ctl, last + 1, | |
108 | key.objectid - last - 1); | |
109 | wake_up(&root->cache_wait); | |
110 | } | |
111 | ||
112 | last = key.objectid; | |
113 | next: | |
114 | path->slots[0]++; | |
115 | } | |
116 | ||
a47d6b70 | 117 | if (last < root->highest_objectid - 1) { |
581bb050 | 118 | __btrfs_add_free_space(ctl, last + 1, |
a47d6b70 | 119 | root->highest_objectid - last - 1); |
581bb050 LZ |
120 | } |
121 | ||
122 | spin_lock(&root->cache_lock); | |
123 | root->cached = BTRFS_CACHE_FINISHED; | |
124 | spin_unlock(&root->cache_lock); | |
125 | ||
126 | root->cache_progress = (u64)-1; | |
127 | btrfs_unpin_free_ino(root); | |
128 | out: | |
129 | wake_up(&root->cache_wait); | |
9e351cc8 | 130 | up_read(&fs_info->commit_root_sem); |
581bb050 LZ |
131 | |
132 | btrfs_free_path(path); | |
133 | ||
134 | return ret; | |
135 | } | |
136 | ||
137 | static void start_caching(struct btrfs_root *root) | |
138 | { | |
a47d6b70 | 139 | struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; |
581bb050 | 140 | struct task_struct *tsk; |
82d5902d | 141 | int ret; |
a47d6b70 | 142 | u64 objectid; |
581bb050 | 143 | |
4b9465cb CM |
144 | if (!btrfs_test_opt(root, INODE_MAP_CACHE)) |
145 | return; | |
146 | ||
581bb050 LZ |
147 | spin_lock(&root->cache_lock); |
148 | if (root->cached != BTRFS_CACHE_NO) { | |
149 | spin_unlock(&root->cache_lock); | |
150 | return; | |
151 | } | |
152 | ||
153 | root->cached = BTRFS_CACHE_STARTED; | |
154 | spin_unlock(&root->cache_lock); | |
155 | ||
82d5902d LZ |
156 | ret = load_free_ino_cache(root->fs_info, root); |
157 | if (ret == 1) { | |
158 | spin_lock(&root->cache_lock); | |
159 | root->cached = BTRFS_CACHE_FINISHED; | |
160 | spin_unlock(&root->cache_lock); | |
161 | return; | |
162 | } | |
163 | ||
a47d6b70 LZ |
164 | /* |
165 | * It can be quite time-consuming to fill the cache by searching | |
166 | * through the extent tree, and this can keep ino allocation path | |
167 | * waiting. Therefore at start we quickly find out the highest | |
168 | * inode number and we know we can use inode numbers which fall in | |
169 | * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID]. | |
170 | */ | |
171 | ret = btrfs_find_free_objectid(root, &objectid); | |
172 | if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) { | |
173 | __btrfs_add_free_space(ctl, objectid, | |
174 | BTRFS_LAST_FREE_OBJECTID - objectid + 1); | |
175 | } | |
176 | ||
581bb050 LZ |
177 | tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu\n", |
178 | root->root_key.objectid); | |
e60efa84 WS |
179 | if (IS_ERR(tsk)) { |
180 | btrfs_warn(root->fs_info, "failed to start inode caching task"); | |
181 | btrfs_clear_and_info(root, CHANGE_INODE_CACHE, | |
182 | "disabling inode map caching"); | |
183 | } | |
581bb050 LZ |
184 | } |
185 | ||
186 | int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid) | |
187 | { | |
4b9465cb CM |
188 | if (!btrfs_test_opt(root, INODE_MAP_CACHE)) |
189 | return btrfs_find_free_objectid(root, objectid); | |
190 | ||
581bb050 LZ |
191 | again: |
192 | *objectid = btrfs_find_ino_for_alloc(root); | |
193 | ||
194 | if (*objectid != 0) | |
195 | return 0; | |
196 | ||
197 | start_caching(root); | |
198 | ||
199 | wait_event(root->cache_wait, | |
200 | root->cached == BTRFS_CACHE_FINISHED || | |
201 | root->free_ino_ctl->free_space > 0); | |
202 | ||
203 | if (root->cached == BTRFS_CACHE_FINISHED && | |
204 | root->free_ino_ctl->free_space == 0) | |
205 | return -ENOSPC; | |
206 | else | |
207 | goto again; | |
208 | } | |
209 | ||
210 | void btrfs_return_ino(struct btrfs_root *root, u64 objectid) | |
211 | { | |
212 | struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; | |
213 | struct btrfs_free_space_ctl *pinned = root->free_ino_pinned; | |
4b9465cb CM |
214 | |
215 | if (!btrfs_test_opt(root, INODE_MAP_CACHE)) | |
216 | return; | |
217 | ||
581bb050 LZ |
218 | again: |
219 | if (root->cached == BTRFS_CACHE_FINISHED) { | |
220 | __btrfs_add_free_space(ctl, objectid, 1); | |
221 | } else { | |
222 | /* | |
223 | * If we are in the process of caching free ino chunks, | |
224 | * to avoid adding the same inode number to the free_ino | |
225 | * tree twice due to cross transaction, we'll leave it | |
226 | * in the pinned tree until a transaction is committed | |
227 | * or the caching work is done. | |
228 | */ | |
229 | ||
9e351cc8 | 230 | down_write(&root->fs_info->commit_root_sem); |
581bb050 LZ |
231 | spin_lock(&root->cache_lock); |
232 | if (root->cached == BTRFS_CACHE_FINISHED) { | |
233 | spin_unlock(&root->cache_lock); | |
9e351cc8 | 234 | up_write(&root->fs_info->commit_root_sem); |
581bb050 LZ |
235 | goto again; |
236 | } | |
237 | spin_unlock(&root->cache_lock); | |
238 | ||
239 | start_caching(root); | |
240 | ||
a47d6b70 | 241 | if (objectid <= root->cache_progress || |
ff76b056 | 242 | objectid >= root->highest_objectid) |
581bb050 LZ |
243 | __btrfs_add_free_space(ctl, objectid, 1); |
244 | else | |
245 | __btrfs_add_free_space(pinned, objectid, 1); | |
246 | ||
9e351cc8 | 247 | up_write(&root->fs_info->commit_root_sem); |
581bb050 LZ |
248 | } |
249 | } | |
250 | ||
251 | /* | |
252 | * When a transaction is committed, we'll move those inode numbers which | |
253 | * are smaller than root->cache_progress from pinned tree to free_ino tree, | |
254 | * and others will just be dropped, because the commit root we were | |
255 | * searching has changed. | |
256 | * | |
9e351cc8 | 257 | * Must be called with root->fs_info->commit_root_sem held |
581bb050 LZ |
258 | */ |
259 | void btrfs_unpin_free_ino(struct btrfs_root *root) | |
260 | { | |
261 | struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; | |
262 | struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset; | |
263 | struct btrfs_free_space *info; | |
264 | struct rb_node *n; | |
265 | u64 count; | |
266 | ||
4b9465cb CM |
267 | if (!btrfs_test_opt(root, INODE_MAP_CACHE)) |
268 | return; | |
269 | ||
581bb050 LZ |
270 | while (1) { |
271 | n = rb_first(rbroot); | |
272 | if (!n) | |
273 | break; | |
274 | ||
275 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
79787eaa | 276 | BUG_ON(info->bitmap); /* Logic error */ |
581bb050 LZ |
277 | |
278 | if (info->offset > root->cache_progress) | |
279 | goto free; | |
280 | else if (info->offset + info->bytes > root->cache_progress) | |
281 | count = root->cache_progress - info->offset + 1; | |
282 | else | |
283 | count = info->bytes; | |
284 | ||
285 | __btrfs_add_free_space(ctl, info->offset, count); | |
286 | free: | |
287 | rb_erase(&info->offset_index, rbroot); | |
288 | kfree(info); | |
289 | } | |
290 | } | |
291 | ||
292 | #define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space)) | |
293 | #define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8) | |
294 | ||
295 | /* | |
296 | * The goal is to keep the memory used by the free_ino tree won't | |
297 | * exceed the memory if we use bitmaps only. | |
298 | */ | |
299 | static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) | |
300 | { | |
301 | struct btrfs_free_space *info; | |
302 | struct rb_node *n; | |
303 | int max_ino; | |
304 | int max_bitmaps; | |
305 | ||
306 | n = rb_last(&ctl->free_space_offset); | |
307 | if (!n) { | |
308 | ctl->extents_thresh = INIT_THRESHOLD; | |
309 | return; | |
310 | } | |
311 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
312 | ||
313 | /* | |
314 | * Find the maximum inode number in the filesystem. Note we | |
315 | * ignore the fact that this can be a bitmap, because we are | |
316 | * not doing precise calculation. | |
317 | */ | |
318 | max_ino = info->bytes - 1; | |
319 | ||
320 | max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP; | |
321 | if (max_bitmaps <= ctl->total_bitmaps) { | |
322 | ctl->extents_thresh = 0; | |
323 | return; | |
324 | } | |
325 | ||
326 | ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) * | |
327 | PAGE_CACHE_SIZE / sizeof(*info); | |
328 | } | |
329 | ||
330 | /* | |
331 | * We don't fall back to bitmap, if we are below the extents threshold | |
332 | * or this chunk of inode numbers is a big one. | |
333 | */ | |
334 | static bool use_bitmap(struct btrfs_free_space_ctl *ctl, | |
335 | struct btrfs_free_space *info) | |
336 | { | |
337 | if (ctl->free_extents < ctl->extents_thresh || | |
338 | info->bytes > INODES_PER_BITMAP / 10) | |
339 | return false; | |
340 | ||
341 | return true; | |
342 | } | |
343 | ||
344 | static struct btrfs_free_space_op free_ino_op = { | |
345 | .recalc_thresholds = recalculate_thresholds, | |
346 | .use_bitmap = use_bitmap, | |
347 | }; | |
348 | ||
349 | static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl) | |
350 | { | |
351 | } | |
352 | ||
353 | static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl, | |
354 | struct btrfs_free_space *info) | |
355 | { | |
356 | /* | |
357 | * We always use extents for two reasons: | |
358 | * | |
359 | * - The pinned tree is only used during the process of caching | |
360 | * work. | |
361 | * - Make code simpler. See btrfs_unpin_free_ino(). | |
362 | */ | |
363 | return false; | |
364 | } | |
365 | ||
366 | static struct btrfs_free_space_op pinned_free_ino_op = { | |
367 | .recalc_thresholds = pinned_recalc_thresholds, | |
368 | .use_bitmap = pinned_use_bitmap, | |
369 | }; | |
370 | ||
371 | void btrfs_init_free_ino_ctl(struct btrfs_root *root) | |
372 | { | |
373 | struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; | |
374 | struct btrfs_free_space_ctl *pinned = root->free_ino_pinned; | |
375 | ||
376 | spin_lock_init(&ctl->tree_lock); | |
377 | ctl->unit = 1; | |
378 | ctl->start = 0; | |
379 | ctl->private = NULL; | |
380 | ctl->op = &free_ino_op; | |
381 | ||
382 | /* | |
383 | * Initially we allow to use 16K of ram to cache chunks of | |
384 | * inode numbers before we resort to bitmaps. This is somewhat | |
385 | * arbitrary, but it will be adjusted in runtime. | |
386 | */ | |
387 | ctl->extents_thresh = INIT_THRESHOLD; | |
388 | ||
389 | spin_lock_init(&pinned->tree_lock); | |
390 | pinned->unit = 1; | |
391 | pinned->start = 0; | |
392 | pinned->private = NULL; | |
393 | pinned->extents_thresh = 0; | |
394 | pinned->op = &pinned_free_ino_op; | |
395 | } | |
396 | ||
82d5902d LZ |
397 | int btrfs_save_ino_cache(struct btrfs_root *root, |
398 | struct btrfs_trans_handle *trans) | |
399 | { | |
400 | struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; | |
401 | struct btrfs_path *path; | |
402 | struct inode *inode; | |
ba38eb4d MX |
403 | struct btrfs_block_rsv *rsv; |
404 | u64 num_bytes; | |
82d5902d LZ |
405 | u64 alloc_hint = 0; |
406 | int ret; | |
407 | int prealloc; | |
408 | bool retry = false; | |
409 | ||
ca456ae2 | 410 | /* only fs tree and subvol/snap needs ino cache */ |
411 | if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID && | |
412 | (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID || | |
413 | root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID)) | |
414 | return 0; | |
415 | ||
d132a538 | 416 | /* Don't save inode cache if we are deleting this root */ |
69e9c6c6 | 417 | if (btrfs_root_refs(&root->root_item) == 0) |
d132a538 JB |
418 | return 0; |
419 | ||
4b9465cb CM |
420 | if (!btrfs_test_opt(root, INODE_MAP_CACHE)) |
421 | return 0; | |
422 | ||
82d5902d LZ |
423 | path = btrfs_alloc_path(); |
424 | if (!path) | |
425 | return -ENOMEM; | |
4b9465cb | 426 | |
ba38eb4d MX |
427 | rsv = trans->block_rsv; |
428 | trans->block_rsv = &root->fs_info->trans_block_rsv; | |
429 | ||
430 | num_bytes = trans->bytes_reserved; | |
431 | /* | |
432 | * 1 item for inode item insertion if need | |
7b61cd92 MX |
433 | * 4 items for inode item update (in the worst case) |
434 | * 1 items for slack space if we need do truncation | |
ba38eb4d MX |
435 | * 1 item for free space object |
436 | * 3 items for pre-allocation | |
437 | */ | |
7b61cd92 | 438 | trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10); |
08e007d2 MX |
439 | ret = btrfs_block_rsv_add(root, trans->block_rsv, |
440 | trans->bytes_reserved, | |
441 | BTRFS_RESERVE_NO_FLUSH); | |
ba38eb4d MX |
442 | if (ret) |
443 | goto out; | |
e77266e4 | 444 | trace_btrfs_space_reservation(root->fs_info, "ino_cache", |
2bcc0328 | 445 | trans->transid, trans->bytes_reserved, 1); |
82d5902d LZ |
446 | again: |
447 | inode = lookup_free_ino_inode(root, path); | |
79787eaa | 448 | if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) { |
82d5902d | 449 | ret = PTR_ERR(inode); |
ba38eb4d | 450 | goto out_release; |
82d5902d LZ |
451 | } |
452 | ||
453 | if (IS_ERR(inode)) { | |
79787eaa | 454 | BUG_ON(retry); /* Logic error */ |
82d5902d LZ |
455 | retry = true; |
456 | ||
457 | ret = create_free_ino_inode(root, trans, path); | |
458 | if (ret) | |
ba38eb4d | 459 | goto out_release; |
82d5902d LZ |
460 | goto again; |
461 | } | |
462 | ||
463 | BTRFS_I(inode)->generation = 0; | |
464 | ret = btrfs_update_inode(trans, root, inode); | |
79787eaa JM |
465 | if (ret) { |
466 | btrfs_abort_transaction(trans, root, ret); | |
467 | goto out_put; | |
468 | } | |
82d5902d LZ |
469 | |
470 | if (i_size_read(inode) > 0) { | |
74514323 | 471 | ret = btrfs_truncate_free_space_cache(root, trans, inode); |
79787eaa | 472 | if (ret) { |
7cfa9e51 MX |
473 | if (ret != -ENOSPC) |
474 | btrfs_abort_transaction(trans, root, ret); | |
82d5902d | 475 | goto out_put; |
79787eaa | 476 | } |
82d5902d LZ |
477 | } |
478 | ||
479 | spin_lock(&root->cache_lock); | |
480 | if (root->cached != BTRFS_CACHE_FINISHED) { | |
481 | ret = -1; | |
482 | spin_unlock(&root->cache_lock); | |
483 | goto out_put; | |
484 | } | |
485 | spin_unlock(&root->cache_lock); | |
486 | ||
487 | spin_lock(&ctl->tree_lock); | |
488 | prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents; | |
489 | prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE); | |
490 | prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE; | |
491 | spin_unlock(&ctl->tree_lock); | |
492 | ||
493 | /* Just to make sure we have enough space */ | |
494 | prealloc += 8 * PAGE_CACHE_SIZE; | |
495 | ||
c09544e0 | 496 | ret = btrfs_delalloc_reserve_space(inode, prealloc); |
82d5902d LZ |
497 | if (ret) |
498 | goto out_put; | |
499 | ||
500 | ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc, | |
501 | prealloc, prealloc, &alloc_hint); | |
c09544e0 JB |
502 | if (ret) { |
503 | btrfs_delalloc_release_space(inode, prealloc); | |
82d5902d | 504 | goto out_put; |
c09544e0 | 505 | } |
82d5902d LZ |
506 | btrfs_free_reserved_data_space(inode, prealloc); |
507 | ||
53645a91 | 508 | ret = btrfs_write_out_ino_cache(root, trans, path, inode); |
82d5902d LZ |
509 | out_put: |
510 | iput(inode); | |
ba38eb4d | 511 | out_release: |
e77266e4 | 512 | trace_btrfs_space_reservation(root->fs_info, "ino_cache", |
2bcc0328 | 513 | trans->transid, trans->bytes_reserved, 0); |
ba38eb4d | 514 | btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved); |
82d5902d | 515 | out: |
ba38eb4d MX |
516 | trans->block_rsv = rsv; |
517 | trans->bytes_reserved = num_bytes; | |
82d5902d LZ |
518 | |
519 | btrfs_free_path(path); | |
520 | return ret; | |
521 | } | |
522 | ||
581bb050 | 523 | static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid) |
5be6f7f1 CM |
524 | { |
525 | struct btrfs_path *path; | |
526 | int ret; | |
5f39d397 | 527 | struct extent_buffer *l; |
5be6f7f1 | 528 | struct btrfs_key search_key; |
5f39d397 | 529 | struct btrfs_key found_key; |
5be6f7f1 CM |
530 | int slot; |
531 | ||
532 | path = btrfs_alloc_path(); | |
db5b493a TI |
533 | if (!path) |
534 | return -ENOMEM; | |
5be6f7f1 | 535 | |
6527cdbe ZY |
536 | search_key.objectid = BTRFS_LAST_FREE_OBJECTID; |
537 | search_key.type = -1; | |
5be6f7f1 CM |
538 | search_key.offset = (u64)-1; |
539 | ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); | |
540 | if (ret < 0) | |
541 | goto error; | |
79787eaa | 542 | BUG_ON(ret == 0); /* Corruption */ |
5be6f7f1 CM |
543 | if (path->slots[0] > 0) { |
544 | slot = path->slots[0] - 1; | |
5f39d397 CM |
545 | l = path->nodes[0]; |
546 | btrfs_item_key_to_cpu(l, &found_key, slot); | |
13a8a7c8 YZ |
547 | *objectid = max_t(u64, found_key.objectid, |
548 | BTRFS_FIRST_FREE_OBJECTID - 1); | |
5be6f7f1 | 549 | } else { |
13a8a7c8 | 550 | *objectid = BTRFS_FIRST_FREE_OBJECTID - 1; |
5be6f7f1 CM |
551 | } |
552 | ret = 0; | |
553 | error: | |
554 | btrfs_free_path(path); | |
555 | return ret; | |
556 | } | |
557 | ||
581bb050 | 558 | int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid) |
9f5fae2f | 559 | { |
9f5fae2f | 560 | int ret; |
a2135011 | 561 | mutex_lock(&root->objectid_mutex); |
9f5fae2f | 562 | |
13a8a7c8 | 563 | if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) { |
581bb050 LZ |
564 | ret = btrfs_find_highest_objectid(root, |
565 | &root->highest_objectid); | |
13a8a7c8 YZ |
566 | if (ret) |
567 | goto out; | |
568 | } | |
5b21f2ed | 569 | |
13a8a7c8 YZ |
570 | if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) { |
571 | ret = -ENOSPC; | |
572 | goto out; | |
9f5fae2f | 573 | } |
13a8a7c8 YZ |
574 | |
575 | *objectid = ++root->highest_objectid; | |
576 | ret = 0; | |
577 | out: | |
a2135011 | 578 | mutex_unlock(&root->objectid_mutex); |
9f5fae2f CM |
579 | return ret; |
580 | } |