Add linux-next specific files for 20110716
[linux-2.6/next.git] / fs / btrfs / inode-map.c
blobb4087e0fa8714bca45e5fc026caf3491e212dd14
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
19 #include <linux/delay.h>
20 #include <linux/kthread.h>
21 #include <linux/pagemap.h>
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "free-space-cache.h"
26 #include "inode-map.h"
27 #include "transaction.h"
29 static int caching_kthread(void *data)
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;
41 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
42 return 0;
44 path = btrfs_alloc_path();
45 if (!path)
46 return -ENOMEM;
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;
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 */
58 mutex_lock(&root->fs_commit_mutex);
60 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
61 if (ret < 0)
62 goto out;
64 while (1) {
65 if (btrfs_fs_closing(fs_info))
66 goto out;
68 leaf = path->nodes[0];
69 slot = path->slots[0];
70 if (slot >= btrfs_header_nritems(leaf)) {
71 ret = btrfs_next_leaf(root, path);
72 if (ret < 0)
73 goto out;
74 else if (ret > 0)
75 break;
77 if (need_resched() ||
78 btrfs_transaction_in_commit(fs_info)) {
79 leaf = path->nodes[0];
81 if (btrfs_header_nritems(leaf) == 0) {
82 WARN_ON(1);
83 break;
87 * Save the key so we can advances forward
88 * in the next search.
90 btrfs_item_key_to_cpu(leaf, &key, 0);
91 btrfs_release_path(path);
92 root->cache_progress = last;
93 mutex_unlock(&root->fs_commit_mutex);
94 schedule_timeout(1);
95 goto again;
96 } else
97 continue;
100 btrfs_item_key_to_cpu(leaf, &key, slot);
102 if (key.type != BTRFS_INODE_ITEM_KEY)
103 goto next;
105 if (key.objectid >= root->highest_objectid)
106 break;
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);
114 last = key.objectid;
115 next:
116 path->slots[0]++;
119 if (last < root->highest_objectid - 1) {
120 __btrfs_add_free_space(ctl, last + 1,
121 root->highest_objectid - last - 1);
124 spin_lock(&root->cache_lock);
125 root->cached = BTRFS_CACHE_FINISHED;
126 spin_unlock(&root->cache_lock);
128 root->cache_progress = (u64)-1;
129 btrfs_unpin_free_ino(root);
130 out:
131 wake_up(&root->cache_wait);
132 mutex_unlock(&root->fs_commit_mutex);
134 btrfs_free_path(path);
136 return ret;
139 static void start_caching(struct btrfs_root *root)
141 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
142 struct task_struct *tsk;
143 int ret;
144 u64 objectid;
146 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
147 return;
149 spin_lock(&root->cache_lock);
150 if (root->cached != BTRFS_CACHE_NO) {
151 spin_unlock(&root->cache_lock);
152 return;
155 root->cached = BTRFS_CACHE_STARTED;
156 spin_unlock(&root->cache_lock);
158 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;
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].
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);
179 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu\n",
180 root->root_key.objectid);
181 BUG_ON(IS_ERR(tsk));
184 int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
186 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
187 return btrfs_find_free_objectid(root, objectid);
189 again:
190 *objectid = btrfs_find_ino_for_alloc(root);
192 if (*objectid != 0)
193 return 0;
195 start_caching(root);
197 wait_event(root->cache_wait,
198 root->cached == BTRFS_CACHE_FINISHED ||
199 root->free_ino_ctl->free_space > 0);
201 if (root->cached == BTRFS_CACHE_FINISHED &&
202 root->free_ino_ctl->free_space == 0)
203 return -ENOSPC;
204 else
205 goto again;
208 void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
210 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
211 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
213 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
214 return;
216 again:
217 if (root->cached == BTRFS_CACHE_FINISHED) {
218 __btrfs_add_free_space(ctl, objectid, 1);
219 } else {
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.
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;
235 spin_unlock(&root->cache_lock);
237 start_caching(root);
239 if (objectid <= root->cache_progress ||
240 objectid > root->highest_objectid)
241 __btrfs_add_free_space(ctl, objectid, 1);
242 else
243 __btrfs_add_free_space(pinned, objectid, 1);
245 mutex_unlock(&root->fs_commit_mutex);
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.
255 * Must be called with root->fs_commit_mutex held
257 void btrfs_unpin_free_ino(struct btrfs_root *root)
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;
265 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
266 return;
268 while (1) {
269 n = rb_first(rbroot);
270 if (!n)
271 break;
273 info = rb_entry(n, struct btrfs_free_space, offset_index);
274 BUG_ON(info->bitmap);
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;
283 __btrfs_add_free_space(ctl, info->offset, count);
284 free:
285 rb_erase(&info->offset_index, rbroot);
286 kfree(info);
290 #define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space))
291 #define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8)
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.
297 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
299 struct btrfs_free_space *info;
300 struct rb_node *n;
301 int max_ino;
302 int max_bitmaps;
304 n = rb_last(&ctl->free_space_offset);
305 if (!n) {
306 ctl->extents_thresh = INIT_THRESHOLD;
307 return;
309 info = rb_entry(n, struct btrfs_free_space, offset_index);
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.
316 max_ino = info->bytes - 1;
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;
324 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
325 PAGE_CACHE_SIZE / sizeof(*info);
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.
332 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
333 struct btrfs_free_space *info)
335 if (ctl->free_extents < ctl->extents_thresh ||
336 info->bytes > INODES_PER_BITMAP / 10)
337 return false;
339 return true;
342 static struct btrfs_free_space_op free_ino_op = {
343 .recalc_thresholds = recalculate_thresholds,
344 .use_bitmap = use_bitmap,
347 static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
351 static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
352 struct btrfs_free_space *info)
355 * We always use extents for two reasons:
357 * - The pinned tree is only used during the process of caching
358 * work.
359 * - Make code simpler. See btrfs_unpin_free_ino().
361 return false;
364 static struct btrfs_free_space_op pinned_free_ino_op = {
365 .recalc_thresholds = pinned_recalc_thresholds,
366 .use_bitmap = pinned_use_bitmap,
369 void btrfs_init_free_ino_ctl(struct btrfs_root *root)
371 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
372 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
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;
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.
385 ctl->extents_thresh = INIT_THRESHOLD;
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;
395 int btrfs_save_ino_cache(struct btrfs_root *root,
396 struct btrfs_trans_handle *trans)
398 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
399 struct btrfs_path *path;
400 struct inode *inode;
401 u64 alloc_hint = 0;
402 int ret;
403 int prealloc;
404 bool retry = false;
406 /* only fs tree and subvol/snap needs ino cache */
407 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
408 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
409 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
410 return 0;
412 /* Don't save inode cache if we are deleting this root */
413 if (btrfs_root_refs(&root->root_item) == 0 &&
414 root != root->fs_info->tree_root)
415 return 0;
417 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
418 return 0;
420 path = btrfs_alloc_path();
421 if (!path)
422 return -ENOMEM;
424 again:
425 inode = lookup_free_ino_inode(root, path);
426 if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
427 ret = PTR_ERR(inode);
428 goto out;
431 if (IS_ERR(inode)) {
432 BUG_ON(retry);
433 retry = true;
435 ret = create_free_ino_inode(root, trans, path);
436 if (ret)
437 goto out;
438 goto again;
441 BTRFS_I(inode)->generation = 0;
442 ret = btrfs_update_inode(trans, root, inode);
443 WARN_ON(ret);
445 if (i_size_read(inode) > 0) {
446 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
447 if (ret)
448 goto out_put;
451 spin_lock(&root->cache_lock);
452 if (root->cached != BTRFS_CACHE_FINISHED) {
453 ret = -1;
454 spin_unlock(&root->cache_lock);
455 goto out_put;
457 spin_unlock(&root->cache_lock);
459 spin_lock(&ctl->tree_lock);
460 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
461 prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE);
462 prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE;
463 spin_unlock(&ctl->tree_lock);
465 /* Just to make sure we have enough space */
466 prealloc += 8 * PAGE_CACHE_SIZE;
468 ret = btrfs_check_data_free_space(inode, prealloc);
469 if (ret)
470 goto out_put;
472 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
473 prealloc, prealloc, &alloc_hint);
474 if (ret)
475 goto out_put;
476 btrfs_free_reserved_data_space(inode, prealloc);
478 out_put:
479 iput(inode);
480 out:
481 if (ret == 0)
482 ret = btrfs_write_out_ino_cache(root, trans, path);
484 btrfs_free_path(path);
485 return ret;
488 static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
490 struct btrfs_path *path;
491 int ret;
492 struct extent_buffer *l;
493 struct btrfs_key search_key;
494 struct btrfs_key found_key;
495 int slot;
497 path = btrfs_alloc_path();
498 if (!path)
499 return -ENOMEM;
501 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
502 search_key.type = -1;
503 search_key.offset = (u64)-1;
504 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
505 if (ret < 0)
506 goto error;
507 BUG_ON(ret == 0);
508 if (path->slots[0] > 0) {
509 slot = path->slots[0] - 1;
510 l = path->nodes[0];
511 btrfs_item_key_to_cpu(l, &found_key, slot);
512 *objectid = max_t(u64, found_key.objectid,
513 BTRFS_FIRST_FREE_OBJECTID - 1);
514 } else {
515 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
517 ret = 0;
518 error:
519 btrfs_free_path(path);
520 return ret;
523 int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
525 int ret;
526 mutex_lock(&root->objectid_mutex);
528 if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
529 ret = btrfs_find_highest_objectid(root,
530 &root->highest_objectid);
531 if (ret)
532 goto out;
535 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
536 ret = -ENOSPC;
537 goto out;
540 *objectid = ++root->highest_objectid;
541 ret = 0;
542 out:
543 mutex_unlock(&root->objectid_mutex);
544 return ret;