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>
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;
35 struct btrfs_path *path;
36 struct extent_buffer *leaf;
41 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
44 path = btrfs_alloc_path();
48 /* Since the commit root is read-only, we can safely skip locking. */
49 path->skip_locking = 1;
50 path->search_commit_root = 1;
53 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
55 key.type = BTRFS_INODE_ITEM_KEY;
57 /* need to make sure the commit_root doesn't disappear */
58 down_read(&fs_info->commit_root_sem);
60 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
65 if (btrfs_fs_closing(fs_info))
68 leaf = path->nodes[0];
69 slot = path->slots[0];
70 if (slot >= btrfs_header_nritems(leaf)) {
71 ret = btrfs_next_leaf(root, path);
78 btrfs_transaction_in_commit(fs_info)) {
79 leaf = path->nodes[0];
81 if (WARN_ON(btrfs_header_nritems(leaf) == 0))
85 * Save the key so we can advances forward
88 btrfs_item_key_to_cpu(leaf, &key, 0);
89 btrfs_release_path(path);
90 root->cache_progress = last;
91 up_read(&fs_info->commit_root_sem);
98 btrfs_item_key_to_cpu(leaf, &key, slot);
100 if (key.type != BTRFS_INODE_ITEM_KEY)
103 if (key.objectid >= root->highest_objectid)
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);
117 if (last < root->highest_objectid - 1) {
118 __btrfs_add_free_space(ctl, last + 1,
119 root->highest_objectid - last - 1);
122 spin_lock(&root->cache_lock);
123 root->cached = BTRFS_CACHE_FINISHED;
124 spin_unlock(&root->cache_lock);
126 root->cache_progress = (u64)-1;
127 btrfs_unpin_free_ino(root);
129 wake_up(&root->cache_wait);
130 up_read(&fs_info->commit_root_sem);
132 btrfs_free_path(path);
137 static void start_caching(struct btrfs_root *root)
139 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
140 struct task_struct *tsk;
144 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
147 spin_lock(&root->cache_lock);
148 if (root->cached != BTRFS_CACHE_NO) {
149 spin_unlock(&root->cache_lock);
153 root->cached = BTRFS_CACHE_STARTED;
154 spin_unlock(&root->cache_lock);
156 ret = load_free_ino_cache(root->fs_info, root);
158 spin_lock(&root->cache_lock);
159 root->cached = BTRFS_CACHE_FINISHED;
160 spin_unlock(&root->cache_lock);
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].
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);
177 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu",
178 root->root_key.objectid);
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");
186 int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
188 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
189 return btrfs_find_free_objectid(root, objectid);
192 *objectid = btrfs_find_ino_for_alloc(root);
199 wait_event(root->cache_wait,
200 root->cached == BTRFS_CACHE_FINISHED ||
201 root->free_ino_ctl->free_space > 0);
203 if (root->cached == BTRFS_CACHE_FINISHED &&
204 root->free_ino_ctl->free_space == 0)
210 void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
212 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
214 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
217 if (root->cached == BTRFS_CACHE_FINISHED) {
218 __btrfs_add_free_space(pinned, objectid, 1);
220 down_write(&root->fs_info->commit_root_sem);
221 spin_lock(&root->cache_lock);
222 if (root->cached == BTRFS_CACHE_FINISHED) {
223 spin_unlock(&root->cache_lock);
224 up_write(&root->fs_info->commit_root_sem);
227 spin_unlock(&root->cache_lock);
231 __btrfs_add_free_space(pinned, objectid, 1);
233 up_write(&root->fs_info->commit_root_sem);
238 * When a transaction is committed, we'll move those inode numbers which
239 * are smaller than root->cache_progress from pinned tree to free_ino tree,
240 * and others will just be dropped, because the commit root we were
241 * searching has changed.
243 * Must be called with root->fs_info->commit_root_sem held
245 void btrfs_unpin_free_ino(struct btrfs_root *root)
247 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
248 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
249 spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock;
250 struct btrfs_free_space *info;
254 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
258 bool add_to_ctl = true;
260 spin_lock(rbroot_lock);
261 n = rb_first(rbroot);
263 spin_unlock(rbroot_lock);
267 info = rb_entry(n, struct btrfs_free_space, offset_index);
268 BUG_ON(info->bitmap); /* Logic error */
270 if (info->offset > root->cache_progress)
272 else if (info->offset + info->bytes > root->cache_progress)
273 count = root->cache_progress - info->offset + 1;
277 rb_erase(&info->offset_index, rbroot);
278 spin_unlock(rbroot_lock);
280 __btrfs_add_free_space(ctl, info->offset, count);
281 kmem_cache_free(btrfs_free_space_cachep, info);
285 #define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space))
286 #define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8)
289 * The goal is to keep the memory used by the free_ino tree won't
290 * exceed the memory if we use bitmaps only.
292 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
294 struct btrfs_free_space *info;
299 n = rb_last(&ctl->free_space_offset);
301 ctl->extents_thresh = INIT_THRESHOLD;
304 info = rb_entry(n, struct btrfs_free_space, offset_index);
307 * Find the maximum inode number in the filesystem. Note we
308 * ignore the fact that this can be a bitmap, because we are
309 * not doing precise calculation.
311 max_ino = info->bytes - 1;
313 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
314 if (max_bitmaps <= ctl->total_bitmaps) {
315 ctl->extents_thresh = 0;
319 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
320 PAGE_CACHE_SIZE / sizeof(*info);
324 * We don't fall back to bitmap, if we are below the extents threshold
325 * or this chunk of inode numbers is a big one.
327 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
328 struct btrfs_free_space *info)
330 if (ctl->free_extents < ctl->extents_thresh ||
331 info->bytes > INODES_PER_BITMAP / 10)
337 static struct btrfs_free_space_op free_ino_op = {
338 .recalc_thresholds = recalculate_thresholds,
339 .use_bitmap = use_bitmap,
342 static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
346 static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
347 struct btrfs_free_space *info)
350 * We always use extents for two reasons:
352 * - The pinned tree is only used during the process of caching
354 * - Make code simpler. See btrfs_unpin_free_ino().
359 static struct btrfs_free_space_op pinned_free_ino_op = {
360 .recalc_thresholds = pinned_recalc_thresholds,
361 .use_bitmap = pinned_use_bitmap,
364 void btrfs_init_free_ino_ctl(struct btrfs_root *root)
366 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
367 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
369 spin_lock_init(&ctl->tree_lock);
373 ctl->op = &free_ino_op;
376 * Initially we allow to use 16K of ram to cache chunks of
377 * inode numbers before we resort to bitmaps. This is somewhat
378 * arbitrary, but it will be adjusted in runtime.
380 ctl->extents_thresh = INIT_THRESHOLD;
382 spin_lock_init(&pinned->tree_lock);
385 pinned->private = NULL;
386 pinned->extents_thresh = 0;
387 pinned->op = &pinned_free_ino_op;
390 int btrfs_save_ino_cache(struct btrfs_root *root,
391 struct btrfs_trans_handle *trans)
393 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
394 struct btrfs_path *path;
396 struct btrfs_block_rsv *rsv;
403 /* only fs tree and subvol/snap needs ino cache */
404 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
405 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
406 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
409 /* Don't save inode cache if we are deleting this root */
410 if (btrfs_root_refs(&root->root_item) == 0)
413 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
416 path = btrfs_alloc_path();
420 rsv = trans->block_rsv;
421 trans->block_rsv = &root->fs_info->trans_block_rsv;
423 num_bytes = trans->bytes_reserved;
425 * 1 item for inode item insertion if need
426 * 4 items for inode item update (in the worst case)
427 * 1 items for slack space if we need do truncation
428 * 1 item for free space object
429 * 3 items for pre-allocation
431 trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10);
432 ret = btrfs_block_rsv_add(root, trans->block_rsv,
433 trans->bytes_reserved,
434 BTRFS_RESERVE_NO_FLUSH);
437 trace_btrfs_space_reservation(root->fs_info, "ino_cache",
438 trans->transid, trans->bytes_reserved, 1);
440 inode = lookup_free_ino_inode(root, path);
441 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
442 ret = PTR_ERR(inode);
447 BUG_ON(retry); /* Logic error */
450 ret = create_free_ino_inode(root, trans, path);
456 BTRFS_I(inode)->generation = 0;
457 ret = btrfs_update_inode(trans, root, inode);
459 btrfs_abort_transaction(trans, root, ret);
463 if (i_size_read(inode) > 0) {
464 ret = btrfs_truncate_free_space_cache(root, trans, inode);
467 btrfs_abort_transaction(trans, root, ret);
472 spin_lock(&root->cache_lock);
473 if (root->cached != BTRFS_CACHE_FINISHED) {
475 spin_unlock(&root->cache_lock);
478 spin_unlock(&root->cache_lock);
480 spin_lock(&ctl->tree_lock);
481 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
482 prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE);
483 prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE;
484 spin_unlock(&ctl->tree_lock);
486 /* Just to make sure we have enough space */
487 prealloc += 8 * PAGE_CACHE_SIZE;
489 ret = btrfs_delalloc_reserve_space(inode, prealloc);
493 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
494 prealloc, prealloc, &alloc_hint);
496 btrfs_delalloc_release_space(inode, prealloc);
499 btrfs_free_reserved_data_space(inode, prealloc);
501 ret = btrfs_write_out_ino_cache(root, trans, path, inode);
505 trace_btrfs_space_reservation(root->fs_info, "ino_cache",
506 trans->transid, trans->bytes_reserved, 0);
507 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
509 trans->block_rsv = rsv;
510 trans->bytes_reserved = num_bytes;
512 btrfs_free_path(path);
516 static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
518 struct btrfs_path *path;
520 struct extent_buffer *l;
521 struct btrfs_key search_key;
522 struct btrfs_key found_key;
525 path = btrfs_alloc_path();
529 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
530 search_key.type = -1;
531 search_key.offset = (u64)-1;
532 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
535 BUG_ON(ret == 0); /* Corruption */
536 if (path->slots[0] > 0) {
537 slot = path->slots[0] - 1;
539 btrfs_item_key_to_cpu(l, &found_key, slot);
540 *objectid = max_t(u64, found_key.objectid,
541 BTRFS_FIRST_FREE_OBJECTID - 1);
543 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
547 btrfs_free_path(path);
551 int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
554 mutex_lock(&root->objectid_mutex);
556 if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
557 ret = btrfs_find_highest_objectid(root,
558 &root->highest_objectid);
563 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
568 *objectid = ++root->highest_objectid;
571 mutex_unlock(&root->objectid_mutex);