blob: 2c66ddbbe670e0ab80753dc41eb4054aacd00388 [file] [log] [blame]
Chris Mason6cbd5572007-06-12 09:07:21 -04001/*
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
Li Zefan581bb052011-04-20 10:06:11 +080019#include <linux/delay.h>
20#include <linux/kthread.h>
21#include <linux/pagemap.h>
22
Chris Mason9f5fae22007-03-20 14:38:32 -040023#include "ctree.h"
24#include "disk-io.h"
Li Zefan581bb052011-04-20 10:06:11 +080025#include "free-space-cache.h"
26#include "inode-map.h"
Chris Mason9f5fae22007-03-20 14:38:32 -040027#include "transaction.h"
28
Li Zefan581bb052011-04-20 10:06:11 +080029static 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
Chris Mason4b9465c2011-06-03 09:36:29 -040041 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
42 return 0;
43
Li Zefan581bb052011-04-20 10:06:11 +080044 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;
56again:
57 /* need to make sure the commit_root doesn't disappear */
58 mutex_lock(&root->fs_commit_mutex);
59
60 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
61 if (ret < 0)
62 goto out;
63
64 while (1) {
David Sterba7841cb22011-05-31 18:07:27 +020065 if (btrfs_fs_closing(fs_info))
Li Zefan581bb052011-04-20 10:06:11 +080066 goto out;
67
68 leaf = path->nodes[0];
69 slot = path->slots[0];
Li Zefana47d6b72011-05-26 06:38:30 +000070 if (slot >= btrfs_header_nritems(leaf)) {
Li Zefan581bb052011-04-20 10:06:11 +080071 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
81 if (btrfs_header_nritems(leaf) == 0) {
82 WARN_ON(1);
83 break;
84 }
85
86 /*
87 * Save the key so we can advances forward
88 * in the next search.
89 */
90 btrfs_item_key_to_cpu(leaf, &key, 0);
Chris Mason945d8962011-05-22 12:33:42 -040091 btrfs_release_path(path);
Li Zefan581bb052011-04-20 10:06:11 +080092 root->cache_progress = last;
93 mutex_unlock(&root->fs_commit_mutex);
94 schedule_timeout(1);
95 goto again;
96 } else
97 continue;
98 }
99
100 btrfs_item_key_to_cpu(leaf, &key, slot);
101
102 if (key.type != BTRFS_INODE_ITEM_KEY)
103 goto next;
104
Li Zefana47d6b72011-05-26 06:38:30 +0000105 if (key.objectid >= root->highest_objectid)
Li Zefan581bb052011-04-20 10:06:11 +0800106 break;
107
108 if (last != (u64)-1 && last + 1 != key.objectid) {
109 __btrfs_add_free_space(ctl, last + 1,
110 key.objectid - last - 1);
111 wake_up(&root->cache_wait);
112 }
113
114 last = key.objectid;
115next:
116 path->slots[0]++;
117 }
118
Li Zefana47d6b72011-05-26 06:38:30 +0000119 if (last < root->highest_objectid - 1) {
Li Zefan581bb052011-04-20 10:06:11 +0800120 __btrfs_add_free_space(ctl, last + 1,
Li Zefana47d6b72011-05-26 06:38:30 +0000121 root->highest_objectid - last - 1);
Li Zefan581bb052011-04-20 10:06:11 +0800122 }
123
124 spin_lock(&root->cache_lock);
125 root->cached = BTRFS_CACHE_FINISHED;
126 spin_unlock(&root->cache_lock);
127
128 root->cache_progress = (u64)-1;
129 btrfs_unpin_free_ino(root);
130out:
131 wake_up(&root->cache_wait);
132 mutex_unlock(&root->fs_commit_mutex);
133
134 btrfs_free_path(path);
135
136 return ret;
137}
138
139static void start_caching(struct btrfs_root *root)
140{
Li Zefana47d6b72011-05-26 06:38:30 +0000141 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
Li Zefan581bb052011-04-20 10:06:11 +0800142 struct task_struct *tsk;
Li Zefan82d59022011-04-20 10:33:24 +0800143 int ret;
Li Zefana47d6b72011-05-26 06:38:30 +0000144 u64 objectid;
Li Zefan581bb052011-04-20 10:06:11 +0800145
Chris Mason4b9465c2011-06-03 09:36:29 -0400146 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
147 return;
148
Li Zefan581bb052011-04-20 10:06:11 +0800149 spin_lock(&root->cache_lock);
150 if (root->cached != BTRFS_CACHE_NO) {
151 spin_unlock(&root->cache_lock);
152 return;
153 }
154
155 root->cached = BTRFS_CACHE_STARTED;
156 spin_unlock(&root->cache_lock);
157
Li Zefan82d59022011-04-20 10:33:24 +0800158 ret = load_free_ino_cache(root->fs_info, root);
159 if (ret == 1) {
160 spin_lock(&root->cache_lock);
161 root->cached = BTRFS_CACHE_FINISHED;
162 spin_unlock(&root->cache_lock);
163 return;
164 }
165
Li Zefana47d6b72011-05-26 06:38:30 +0000166 /*
167 * It can be quite time-consuming to fill the cache by searching
168 * through the extent tree, and this can keep ino allocation path
169 * waiting. Therefore at start we quickly find out the highest
170 * inode number and we know we can use inode numbers which fall in
171 * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID].
172 */
173 ret = btrfs_find_free_objectid(root, &objectid);
174 if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) {
175 __btrfs_add_free_space(ctl, objectid,
176 BTRFS_LAST_FREE_OBJECTID - objectid + 1);
177 }
178
Li Zefan581bb052011-04-20 10:06:11 +0800179 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu\n",
180 root->root_key.objectid);
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100181 BUG_ON(IS_ERR(tsk)); /* -ENOMEM */
Li Zefan581bb052011-04-20 10:06:11 +0800182}
183
184int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
185{
Chris Mason4b9465c2011-06-03 09:36:29 -0400186 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
187 return btrfs_find_free_objectid(root, objectid);
188
Li Zefan581bb052011-04-20 10:06:11 +0800189again:
190 *objectid = btrfs_find_ino_for_alloc(root);
191
192 if (*objectid != 0)
193 return 0;
194
195 start_caching(root);
196
197 wait_event(root->cache_wait,
198 root->cached == BTRFS_CACHE_FINISHED ||
199 root->free_ino_ctl->free_space > 0);
200
201 if (root->cached == BTRFS_CACHE_FINISHED &&
202 root->free_ino_ctl->free_space == 0)
203 return -ENOSPC;
204 else
205 goto again;
206}
207
208void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
209{
210 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
211 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
Chris Mason4b9465c2011-06-03 09:36:29 -0400212
213 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
214 return;
215
Li Zefan581bb052011-04-20 10:06:11 +0800216again:
217 if (root->cached == BTRFS_CACHE_FINISHED) {
218 __btrfs_add_free_space(ctl, objectid, 1);
219 } else {
220 /*
221 * If we are in the process of caching free ino chunks,
222 * to avoid adding the same inode number to the free_ino
223 * tree twice due to cross transaction, we'll leave it
224 * in the pinned tree until a transaction is committed
225 * or the caching work is done.
226 */
227
228 mutex_lock(&root->fs_commit_mutex);
229 spin_lock(&root->cache_lock);
230 if (root->cached == BTRFS_CACHE_FINISHED) {
231 spin_unlock(&root->cache_lock);
232 mutex_unlock(&root->fs_commit_mutex);
233 goto again;
234 }
235 spin_unlock(&root->cache_lock);
236
237 start_caching(root);
238
Li Zefana47d6b72011-05-26 06:38:30 +0000239 if (objectid <= root->cache_progress ||
240 objectid > root->highest_objectid)
Li Zefan581bb052011-04-20 10:06:11 +0800241 __btrfs_add_free_space(ctl, objectid, 1);
242 else
243 __btrfs_add_free_space(pinned, objectid, 1);
244
245 mutex_unlock(&root->fs_commit_mutex);
246 }
247}
248
249/*
250 * When a transaction is committed, we'll move those inode numbers which
251 * are smaller than root->cache_progress from pinned tree to free_ino tree,
252 * and others will just be dropped, because the commit root we were
253 * searching has changed.
254 *
255 * Must be called with root->fs_commit_mutex held
256 */
257void btrfs_unpin_free_ino(struct btrfs_root *root)
258{
259 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
260 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
261 struct btrfs_free_space *info;
262 struct rb_node *n;
263 u64 count;
264
Chris Mason4b9465c2011-06-03 09:36:29 -0400265 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
266 return;
267
Li Zefan581bb052011-04-20 10:06:11 +0800268 while (1) {
269 n = rb_first(rbroot);
270 if (!n)
271 break;
272
273 info = rb_entry(n, struct btrfs_free_space, offset_index);
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100274 BUG_ON(info->bitmap); /* Logic error */
Li Zefan581bb052011-04-20 10:06:11 +0800275
276 if (info->offset > root->cache_progress)
277 goto free;
278 else if (info->offset + info->bytes > root->cache_progress)
279 count = root->cache_progress - info->offset + 1;
280 else
281 count = info->bytes;
282
283 __btrfs_add_free_space(ctl, info->offset, count);
284free:
285 rb_erase(&info->offset_index, rbroot);
286 kfree(info);
287 }
288}
289
290#define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space))
291#define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8)
292
293/*
294 * The goal is to keep the memory used by the free_ino tree won't
295 * exceed the memory if we use bitmaps only.
296 */
297static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
298{
299 struct btrfs_free_space *info;
300 struct rb_node *n;
301 int max_ino;
302 int max_bitmaps;
303
304 n = rb_last(&ctl->free_space_offset);
305 if (!n) {
306 ctl->extents_thresh = INIT_THRESHOLD;
307 return;
308 }
309 info = rb_entry(n, struct btrfs_free_space, offset_index);
310
311 /*
312 * Find the maximum inode number in the filesystem. Note we
313 * ignore the fact that this can be a bitmap, because we are
314 * not doing precise calculation.
315 */
316 max_ino = info->bytes - 1;
317
318 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
319 if (max_bitmaps <= ctl->total_bitmaps) {
320 ctl->extents_thresh = 0;
321 return;
322 }
323
324 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
325 PAGE_CACHE_SIZE / sizeof(*info);
326}
327
328/*
329 * We don't fall back to bitmap, if we are below the extents threshold
330 * or this chunk of inode numbers is a big one.
331 */
332static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
333 struct btrfs_free_space *info)
334{
335 if (ctl->free_extents < ctl->extents_thresh ||
336 info->bytes > INODES_PER_BITMAP / 10)
337 return false;
338
339 return true;
340}
341
342static struct btrfs_free_space_op free_ino_op = {
343 .recalc_thresholds = recalculate_thresholds,
344 .use_bitmap = use_bitmap,
345};
346
347static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
348{
349}
350
351static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
352 struct btrfs_free_space *info)
353{
354 /*
355 * We always use extents for two reasons:
356 *
357 * - The pinned tree is only used during the process of caching
358 * work.
359 * - Make code simpler. See btrfs_unpin_free_ino().
360 */
361 return false;
362}
363
364static struct btrfs_free_space_op pinned_free_ino_op = {
365 .recalc_thresholds = pinned_recalc_thresholds,
366 .use_bitmap = pinned_use_bitmap,
367};
368
369void btrfs_init_free_ino_ctl(struct btrfs_root *root)
370{
371 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
372 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
373
374 spin_lock_init(&ctl->tree_lock);
375 ctl->unit = 1;
376 ctl->start = 0;
377 ctl->private = NULL;
378 ctl->op = &free_ino_op;
379
380 /*
381 * Initially we allow to use 16K of ram to cache chunks of
382 * inode numbers before we resort to bitmaps. This is somewhat
383 * arbitrary, but it will be adjusted in runtime.
384 */
385 ctl->extents_thresh = INIT_THRESHOLD;
386
387 spin_lock_init(&pinned->tree_lock);
388 pinned->unit = 1;
389 pinned->start = 0;
390 pinned->private = NULL;
391 pinned->extents_thresh = 0;
392 pinned->op = &pinned_free_ino_op;
393}
394
Li Zefan82d59022011-04-20 10:33:24 +0800395int btrfs_save_ino_cache(struct btrfs_root *root,
396 struct btrfs_trans_handle *trans)
397{
398 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
399 struct btrfs_path *path;
400 struct inode *inode;
Miao Xieba38eb42011-11-10 20:45:04 -0500401 struct btrfs_block_rsv *rsv;
402 u64 num_bytes;
Li Zefan82d59022011-04-20 10:33:24 +0800403 u64 alloc_hint = 0;
404 int ret;
405 int prealloc;
406 bool retry = false;
407
liuboca456ae2011-06-01 09:42:49 +0000408 /* only fs tree and subvol/snap needs ino cache */
409 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
410 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
411 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
412 return 0;
413
Josef Bacikd132a532011-05-31 19:33:33 +0000414 /* Don't save inode cache if we are deleting this root */
415 if (btrfs_root_refs(&root->root_item) == 0 &&
416 root != root->fs_info->tree_root)
417 return 0;
418
Chris Mason4b9465c2011-06-03 09:36:29 -0400419 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
420 return 0;
421
Li Zefan82d59022011-04-20 10:33:24 +0800422 path = btrfs_alloc_path();
423 if (!path)
424 return -ENOMEM;
Chris Mason4b9465c2011-06-03 09:36:29 -0400425
Miao Xieba38eb42011-11-10 20:45:04 -0500426 rsv = trans->block_rsv;
427 trans->block_rsv = &root->fs_info->trans_block_rsv;
428
429 num_bytes = trans->bytes_reserved;
430 /*
431 * 1 item for inode item insertion if need
Miao Xie7b61cd92013-05-13 13:55:09 +0000432 * 4 items for inode item update (in the worst case)
433 * 1 items for slack space if we need do truncation
Miao Xieba38eb42011-11-10 20:45:04 -0500434 * 1 item for free space object
435 * 3 items for pre-allocation
436 */
Miao Xie7b61cd92013-05-13 13:55:09 +0000437 trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10);
Miao Xie08e007d2012-10-16 11:33:38 +0000438 ret = btrfs_block_rsv_add(root, trans->block_rsv,
439 trans->bytes_reserved,
440 BTRFS_RESERVE_NO_FLUSH);
Miao Xieba38eb42011-11-10 20:45:04 -0500441 if (ret)
442 goto out;
Chris Masone77266e2012-02-24 10:39:05 -0500443 trace_btrfs_space_reservation(root->fs_info, "ino_cache",
Liu Bo2bcc0322012-03-29 09:57:44 -0400444 trans->transid, trans->bytes_reserved, 1);
Li Zefan82d59022011-04-20 10:33:24 +0800445again:
446 inode = lookup_free_ino_inode(root, path);
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100447 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
Li Zefan82d59022011-04-20 10:33:24 +0800448 ret = PTR_ERR(inode);
Miao Xieba38eb42011-11-10 20:45:04 -0500449 goto out_release;
Li Zefan82d59022011-04-20 10:33:24 +0800450 }
451
452 if (IS_ERR(inode)) {
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100453 BUG_ON(retry); /* Logic error */
Li Zefan82d59022011-04-20 10:33:24 +0800454 retry = true;
455
456 ret = create_free_ino_inode(root, trans, path);
457 if (ret)
Miao Xieba38eb42011-11-10 20:45:04 -0500458 goto out_release;
Li Zefan82d59022011-04-20 10:33:24 +0800459 goto again;
460 }
461
462 BTRFS_I(inode)->generation = 0;
463 ret = btrfs_update_inode(trans, root, inode);
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100464 if (ret) {
465 btrfs_abort_transaction(trans, root, ret);
466 goto out_put;
467 }
Li Zefan82d59022011-04-20 10:33:24 +0800468
469 if (i_size_read(inode) > 0) {
470 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100471 if (ret) {
Miao Xie7cfa9e52013-05-13 13:55:08 +0000472 if (ret != -ENOSPC)
473 btrfs_abort_transaction(trans, root, ret);
Li Zefan82d59022011-04-20 10:33:24 +0800474 goto out_put;
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100475 }
Li Zefan82d59022011-04-20 10:33:24 +0800476 }
477
478 spin_lock(&root->cache_lock);
479 if (root->cached != BTRFS_CACHE_FINISHED) {
480 ret = -1;
481 spin_unlock(&root->cache_lock);
482 goto out_put;
483 }
484 spin_unlock(&root->cache_lock);
485
486 spin_lock(&ctl->tree_lock);
487 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
488 prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE);
489 prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE;
490 spin_unlock(&ctl->tree_lock);
491
492 /* Just to make sure we have enough space */
493 prealloc += 8 * PAGE_CACHE_SIZE;
494
Josef Bacikc09544e2011-08-30 10:19:10 -0400495 ret = btrfs_delalloc_reserve_space(inode, prealloc);
Li Zefan82d59022011-04-20 10:33:24 +0800496 if (ret)
497 goto out_put;
498
499 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
500 prealloc, prealloc, &alloc_hint);
Josef Bacikc09544e2011-08-30 10:19:10 -0400501 if (ret) {
502 btrfs_delalloc_release_space(inode, prealloc);
Li Zefan82d59022011-04-20 10:33:24 +0800503 goto out_put;
Josef Bacikc09544e2011-08-30 10:19:10 -0400504 }
Li Zefan82d59022011-04-20 10:33:24 +0800505 btrfs_free_reserved_data_space(inode, prealloc);
506
Miao Xieba38eb42011-11-10 20:45:04 -0500507 ret = btrfs_write_out_ino_cache(root, trans, path);
Li Zefan82d59022011-04-20 10:33:24 +0800508out_put:
509 iput(inode);
Miao Xieba38eb42011-11-10 20:45:04 -0500510out_release:
Chris Masone77266e2012-02-24 10:39:05 -0500511 trace_btrfs_space_reservation(root->fs_info, "ino_cache",
Liu Bo2bcc0322012-03-29 09:57:44 -0400512 trans->transid, trans->bytes_reserved, 0);
Miao Xieba38eb42011-11-10 20:45:04 -0500513 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
Li Zefan82d59022011-04-20 10:33:24 +0800514out:
Miao Xieba38eb42011-11-10 20:45:04 -0500515 trans->block_rsv = rsv;
516 trans->bytes_reserved = num_bytes;
Li Zefan82d59022011-04-20 10:33:24 +0800517
518 btrfs_free_path(path);
519 return ret;
520}
521
Li Zefan581bb052011-04-20 10:06:11 +0800522static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
Chris Mason5be6f7f2007-04-05 13:35:25 -0400523{
524 struct btrfs_path *path;
525 int ret;
Chris Mason5f39d392007-10-15 16:14:19 -0400526 struct extent_buffer *l;
Chris Mason5be6f7f2007-04-05 13:35:25 -0400527 struct btrfs_key search_key;
Chris Mason5f39d392007-10-15 16:14:19 -0400528 struct btrfs_key found_key;
Chris Mason5be6f7f2007-04-05 13:35:25 -0400529 int slot;
530
531 path = btrfs_alloc_path();
Tsutomu Itohdb5b4932011-03-23 08:14:16 +0000532 if (!path)
533 return -ENOMEM;
Chris Mason5be6f7f2007-04-05 13:35:25 -0400534
Zheng Yan6527cdb2008-09-05 16:43:53 -0400535 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
536 search_key.type = -1;
Chris Mason5be6f7f2007-04-05 13:35:25 -0400537 search_key.offset = (u64)-1;
538 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
539 if (ret < 0)
540 goto error;
Jeff Mahoney79787ea2012-03-12 16:03:00 +0100541 BUG_ON(ret == 0); /* Corruption */
Chris Mason5be6f7f2007-04-05 13:35:25 -0400542 if (path->slots[0] > 0) {
543 slot = path->slots[0] - 1;
Chris Mason5f39d392007-10-15 16:14:19 -0400544 l = path->nodes[0];
545 btrfs_item_key_to_cpu(l, &found_key, slot);
Yan, Zheng13a8a7c2009-09-21 15:56:00 -0400546 *objectid = max_t(u64, found_key.objectid,
547 BTRFS_FIRST_FREE_OBJECTID - 1);
Chris Mason5be6f7f2007-04-05 13:35:25 -0400548 } else {
Yan, Zheng13a8a7c2009-09-21 15:56:00 -0400549 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
Chris Mason5be6f7f2007-04-05 13:35:25 -0400550 }
551 ret = 0;
552error:
553 btrfs_free_path(path);
554 return ret;
555}
556
Li Zefan581bb052011-04-20 10:06:11 +0800557int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
Chris Mason9f5fae22007-03-20 14:38:32 -0400558{
Chris Mason9f5fae22007-03-20 14:38:32 -0400559 int ret;
Chris Masona2135012008-06-25 16:01:30 -0400560 mutex_lock(&root->objectid_mutex);
Yan, Zheng13a8a7c2009-09-21 15:56:00 -0400561
562 if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
Li Zefan581bb052011-04-20 10:06:11 +0800563 ret = btrfs_find_highest_objectid(root,
564 &root->highest_objectid);
Yan, Zheng13a8a7c2009-09-21 15:56:00 -0400565 if (ret)
566 goto out;
Chris Masona2135012008-06-25 16:01:30 -0400567 }
Chris Masonb1a4d962007-04-04 15:27:52 -0400568
Yan, Zheng13a8a7c2009-09-21 15:56:00 -0400569 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
570 ret = -ENOSPC;
571 goto out;
Chris Mason9f5fae22007-03-20 14:38:32 -0400572 }
Yan, Zheng13a8a7c2009-09-21 15:56:00 -0400573
574 *objectid = ++root->highest_objectid;
575 ret = 0;
576out:
Chris Masona2135012008-06-25 16:01:30 -0400577 mutex_unlock(&root->objectid_mutex);
Chris Mason9f5fae22007-03-20 14:38:32 -0400578 return ret;
579}