2 * Copyright (C) 2008 Red Hat. 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/pagemap.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/math64.h>
24 #include "free-space-cache.h"
25 #include "transaction.h"
28 #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8)
29 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
31 static void recalculate_thresholds(struct btrfs_block_group_cache
33 static int link_free_space(struct btrfs_block_group_cache *block_group,
34 struct btrfs_free_space *info);
36 struct inode *lookup_free_space_inode(struct btrfs_root *root,
37 struct btrfs_block_group_cache
38 *block_group, struct btrfs_path *path)
41 struct btrfs_key location;
42 struct btrfs_disk_key disk_key;
43 struct btrfs_free_space_header *header;
44 struct extent_buffer *leaf;
45 struct inode *inode = NULL;
48 spin_lock(&block_group->lock);
49 if (block_group->inode)
50 inode = igrab(block_group->inode);
51 spin_unlock(&block_group->lock);
55 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
56 key.offset = block_group->key.objectid;
59 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
63 btrfs_release_path(root, path);
64 return ERR_PTR(-ENOENT);
67 leaf = path->nodes[0];
68 header = btrfs_item_ptr(leaf, path->slots[0],
69 struct btrfs_free_space_header);
70 btrfs_free_space_key(leaf, header, &disk_key);
71 btrfs_disk_key_to_cpu(&location, &disk_key);
72 btrfs_release_path(root, path);
74 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
76 return ERR_PTR(-ENOENT);
79 if (is_bad_inode(inode)) {
81 return ERR_PTR(-ENOENT);
84 spin_lock(&block_group->lock);
85 if (!root->fs_info->closing) {
86 block_group->inode = igrab(inode);
87 block_group->iref = 1;
89 spin_unlock(&block_group->lock);
94 int create_free_space_inode(struct btrfs_root *root,
95 struct btrfs_trans_handle *trans,
96 struct btrfs_block_group_cache *block_group,
97 struct btrfs_path *path)
100 struct btrfs_disk_key disk_key;
101 struct btrfs_free_space_header *header;
102 struct btrfs_inode_item *inode_item;
103 struct extent_buffer *leaf;
107 ret = btrfs_find_free_objectid(trans, root, 0, &objectid);
111 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
115 leaf = path->nodes[0];
116 inode_item = btrfs_item_ptr(leaf, path->slots[0],
117 struct btrfs_inode_item);
118 btrfs_item_key(leaf, &disk_key, path->slots[0]);
119 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
120 sizeof(*inode_item));
121 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
122 btrfs_set_inode_size(leaf, inode_item, 0);
123 btrfs_set_inode_nbytes(leaf, inode_item, 0);
124 btrfs_set_inode_uid(leaf, inode_item, 0);
125 btrfs_set_inode_gid(leaf, inode_item, 0);
126 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
127 btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS |
128 BTRFS_INODE_PREALLOC | BTRFS_INODE_NODATASUM);
129 btrfs_set_inode_nlink(leaf, inode_item, 1);
130 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
131 btrfs_set_inode_block_group(leaf, inode_item,
132 block_group->key.objectid);
133 btrfs_mark_buffer_dirty(leaf);
134 btrfs_release_path(root, path);
136 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
137 key.offset = block_group->key.objectid;
140 ret = btrfs_insert_empty_item(trans, root, path, &key,
141 sizeof(struct btrfs_free_space_header));
143 btrfs_release_path(root, path);
146 leaf = path->nodes[0];
147 header = btrfs_item_ptr(leaf, path->slots[0],
148 struct btrfs_free_space_header);
149 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
150 btrfs_set_free_space_key(leaf, header, &disk_key);
151 btrfs_mark_buffer_dirty(leaf);
152 btrfs_release_path(root, path);
157 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
158 struct btrfs_trans_handle *trans,
159 struct btrfs_path *path,
165 trans->block_rsv = root->orphan_block_rsv;
166 ret = btrfs_block_rsv_check(trans, root,
167 root->orphan_block_rsv,
172 oldsize = i_size_read(inode);
173 btrfs_i_size_write(inode, 0);
174 truncate_pagecache(inode, oldsize, 0);
177 * We don't need an orphan item because truncating the free space cache
178 * will never be split across transactions.
180 ret = btrfs_truncate_inode_items(trans, root, inode,
181 0, BTRFS_EXTENT_DATA_KEY);
187 return btrfs_update_inode(trans, root, inode);
190 static int readahead_cache(struct inode *inode)
192 struct file_ra_state *ra;
193 unsigned long last_index;
195 ra = kzalloc(sizeof(*ra), GFP_NOFS);
199 file_ra_state_init(ra, inode->i_mapping);
200 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
202 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
209 int load_free_space_cache(struct btrfs_fs_info *fs_info,
210 struct btrfs_block_group_cache *block_group)
212 struct btrfs_root *root = fs_info->tree_root;
214 struct btrfs_free_space_header *header;
215 struct extent_buffer *leaf;
217 struct btrfs_path *path;
218 u32 *checksums = NULL, *crc;
219 char *disk_crcs = NULL;
220 struct btrfs_key key;
221 struct list_head bitmaps;
225 u32 cur_crc = ~(u32)0;
227 unsigned long first_page_offset;
232 * If we're unmounting then just return, since this does a search on the
233 * normal root and not the commit root and we could deadlock.
236 if (fs_info->closing)
240 * If this block group has been marked to be cleared for one reason or
241 * another then we can't trust the on disk cache, so just return.
243 spin_lock(&block_group->lock);
244 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
245 spin_unlock(&block_group->lock);
248 spin_unlock(&block_group->lock);
250 INIT_LIST_HEAD(&bitmaps);
252 path = btrfs_alloc_path();
256 inode = lookup_free_space_inode(root, block_group, path);
258 btrfs_free_path(path);
262 /* Nothing in the space cache, goodbye */
263 if (!i_size_read(inode)) {
264 btrfs_free_path(path);
268 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
269 key.offset = block_group->key.objectid;
272 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
274 btrfs_free_path(path);
278 leaf = path->nodes[0];
279 header = btrfs_item_ptr(leaf, path->slots[0],
280 struct btrfs_free_space_header);
281 num_entries = btrfs_free_space_entries(leaf, header);
282 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
283 generation = btrfs_free_space_generation(leaf, header);
284 btrfs_free_path(path);
286 if (BTRFS_I(inode)->generation != generation) {
287 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
288 " not match free space cache generation (%llu) for "
289 "block group %llu\n",
290 (unsigned long long)BTRFS_I(inode)->generation,
291 (unsigned long long)generation,
292 (unsigned long long)block_group->key.objectid);
299 /* Setup everything for doing checksumming */
300 num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
301 checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
304 first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
305 disk_crcs = kzalloc(first_page_offset, GFP_NOFS);
309 ret = readahead_cache(inode);
316 struct btrfs_free_space_entry *entry;
317 struct btrfs_free_space *e;
319 unsigned long offset = 0;
320 unsigned long start_offset = 0;
323 if (!num_entries && !num_bitmaps)
327 start_offset = first_page_offset;
328 offset = start_offset;
331 page = grab_cache_page(inode->i_mapping, index);
337 if (!PageUptodate(page)) {
338 btrfs_readpage(NULL, page);
340 if (!PageUptodate(page)) {
342 page_cache_release(page);
343 printk(KERN_ERR "btrfs: error reading free "
344 "space cache: %llu\n",
346 block_group->key.objectid);
355 memcpy(disk_crcs, addr, first_page_offset);
356 gen = addr + (sizeof(u32) * num_checksums);
357 if (*gen != BTRFS_I(inode)->generation) {
358 printk(KERN_ERR "btrfs: space cache generation"
359 " (%llu) does not match inode (%llu) "
360 "for block group %llu\n",
361 (unsigned long long)*gen,
363 BTRFS_I(inode)->generation,
365 block_group->key.objectid);
368 page_cache_release(page);
371 crc = (u32 *)disk_crcs;
373 entry = addr + start_offset;
375 /* First lets check our crc before we do anything fun */
377 cur_crc = btrfs_csum_data(root, addr + start_offset, cur_crc,
378 PAGE_CACHE_SIZE - start_offset);
379 btrfs_csum_final(cur_crc, (char *)&cur_crc);
380 if (cur_crc != *crc) {
381 printk(KERN_ERR "btrfs: crc mismatch for page %lu in "
382 "block group %llu\n", index,
383 (unsigned long long)block_group->key.objectid);
386 page_cache_release(page);
396 e = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
400 page_cache_release(page);
404 e->offset = le64_to_cpu(entry->offset);
405 e->bytes = le64_to_cpu(entry->bytes);
410 page_cache_release(page);
414 if (entry->type == BTRFS_FREE_SPACE_EXTENT) {
415 spin_lock(&block_group->tree_lock);
416 ret = link_free_space(block_group, e);
417 spin_unlock(&block_group->tree_lock);
420 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
425 page_cache_release(page);
428 spin_lock(&block_group->tree_lock);
429 ret = link_free_space(block_group, e);
430 block_group->total_bitmaps++;
431 recalculate_thresholds(block_group);
432 spin_unlock(&block_group->tree_lock);
433 list_add_tail(&e->list, &bitmaps);
437 offset += sizeof(struct btrfs_free_space_entry);
438 if (offset + sizeof(struct btrfs_free_space_entry) >=
445 * We read an entry out of this page, we need to move on to the
454 * We add the bitmaps at the end of the entries in order that
455 * the bitmap entries are added to the cache.
457 e = list_entry(bitmaps.next, struct btrfs_free_space, list);
458 list_del_init(&e->list);
459 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE);
464 page_cache_release(page);
476 /* This cache is bogus, make sure it gets cleared */
477 spin_lock(&block_group->lock);
478 block_group->disk_cache_state = BTRFS_DC_CLEAR;
479 spin_unlock(&block_group->lock);
480 btrfs_remove_free_space_cache(block_group);
484 int btrfs_write_out_cache(struct btrfs_root *root,
485 struct btrfs_trans_handle *trans,
486 struct btrfs_block_group_cache *block_group,
487 struct btrfs_path *path)
489 struct btrfs_free_space_header *header;
490 struct extent_buffer *leaf;
492 struct rb_node *node;
493 struct list_head *pos, *n;
495 struct extent_state *cached_state = NULL;
496 struct list_head bitmap_list;
497 struct btrfs_key key;
499 u32 *crc, *checksums;
500 pgoff_t index = 0, last_index = 0;
501 unsigned long first_page_offset;
507 root = root->fs_info->tree_root;
509 INIT_LIST_HEAD(&bitmap_list);
511 spin_lock(&block_group->lock);
512 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
513 spin_unlock(&block_group->lock);
516 spin_unlock(&block_group->lock);
518 inode = lookup_free_space_inode(root, block_group, path);
522 if (!i_size_read(inode)) {
527 node = rb_first(&block_group->free_space_offset);
533 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
534 filemap_write_and_wait(inode->i_mapping);
535 btrfs_wait_ordered_range(inode, inode->i_size &
536 ~(root->sectorsize - 1), (u64)-1);
538 /* We need a checksum per page. */
539 num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
540 crc = checksums = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
546 /* Since the first page has all of our checksums and our generation we
547 * need to calculate the offset into the page that we can start writing
550 first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
553 * Lock all pages first so we can lock the extent safely.
555 * NOTE: Because we hold the ref the entire time we're going to write to
556 * the page find_get_page should never fail, so we don't do a check
557 * after find_get_page at this point. Just putting this here so people
558 * know and don't freak out.
560 while (index <= last_index) {
561 page = grab_cache_page(inode->i_mapping, index);
566 page = find_get_page(inode->i_mapping, i);
568 page_cache_release(page);
569 page_cache_release(page);
578 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
579 0, &cached_state, GFP_NOFS);
581 /* Write out the extent entries */
583 struct btrfs_free_space_entry *entry;
585 unsigned long offset = 0;
586 unsigned long start_offset = 0;
589 start_offset = first_page_offset;
590 offset = start_offset;
593 page = find_get_page(inode->i_mapping, index);
596 entry = addr + start_offset;
598 memset(addr, 0, PAGE_CACHE_SIZE);
600 struct btrfs_free_space *e;
602 e = rb_entry(node, struct btrfs_free_space, offset_index);
605 entry->offset = cpu_to_le64(e->offset);
606 entry->bytes = cpu_to_le64(e->bytes);
608 entry->type = BTRFS_FREE_SPACE_BITMAP;
609 list_add_tail(&e->list, &bitmap_list);
612 entry->type = BTRFS_FREE_SPACE_EXTENT;
614 node = rb_next(node);
617 offset += sizeof(struct btrfs_free_space_entry);
618 if (offset + sizeof(struct btrfs_free_space_entry) >=
624 *crc = btrfs_csum_data(root, addr + start_offset, *crc,
625 PAGE_CACHE_SIZE - start_offset);
628 btrfs_csum_final(*crc, (char *)crc);
631 bytes += PAGE_CACHE_SIZE;
633 ClearPageChecked(page);
634 set_page_extent_mapped(page);
635 SetPageUptodate(page);
636 set_page_dirty(page);
639 * We need to release our reference we got for grab_cache_page,
640 * except for the first page which will hold our checksums, we
645 page_cache_release(page);
648 page_cache_release(page);
653 /* Write out the bitmaps */
654 list_for_each_safe(pos, n, &bitmap_list) {
656 struct btrfs_free_space *entry =
657 list_entry(pos, struct btrfs_free_space, list);
659 page = find_get_page(inode->i_mapping, index);
662 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE);
664 *crc = btrfs_csum_data(root, addr, *crc, PAGE_CACHE_SIZE);
666 btrfs_csum_final(*crc, (char *)crc);
668 bytes += PAGE_CACHE_SIZE;
670 ClearPageChecked(page);
671 set_page_extent_mapped(page);
672 SetPageUptodate(page);
673 set_page_dirty(page);
675 page_cache_release(page);
676 page_cache_release(page);
677 list_del_init(&entry->list);
681 /* Zero out the rest of the pages just to make sure */
682 while (index <= last_index) {
685 page = find_get_page(inode->i_mapping, index);
688 memset(addr, 0, PAGE_CACHE_SIZE);
690 ClearPageChecked(page);
691 set_page_extent_mapped(page);
692 SetPageUptodate(page);
693 set_page_dirty(page);
695 page_cache_release(page);
696 page_cache_release(page);
697 bytes += PAGE_CACHE_SIZE;
701 btrfs_set_extent_delalloc(inode, 0, bytes - 1, &cached_state);
703 /* Write the checksums and trans id to the first page */
708 page = find_get_page(inode->i_mapping, 0);
711 memcpy(addr, checksums, sizeof(u32) * num_checksums);
712 gen = addr + (sizeof(u32) * num_checksums);
713 *gen = trans->transid;
715 ClearPageChecked(page);
716 set_page_extent_mapped(page);
717 SetPageUptodate(page);
718 set_page_dirty(page);
720 page_cache_release(page);
721 page_cache_release(page);
723 BTRFS_I(inode)->generation = trans->transid;
725 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
726 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
728 filemap_write_and_wait(inode->i_mapping);
730 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
731 key.offset = block_group->key.objectid;
734 ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
737 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
738 EXTENT_DIRTY | EXTENT_DELALLOC |
739 EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS);
742 leaf = path->nodes[0];
744 struct btrfs_key found_key;
745 BUG_ON(!path->slots[0]);
747 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
748 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
749 found_key.offset != block_group->key.objectid) {
751 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
752 EXTENT_DIRTY | EXTENT_DELALLOC |
753 EXTENT_DO_ACCOUNTING, 0, 0, NULL,
755 btrfs_release_path(root, path);
759 header = btrfs_item_ptr(leaf, path->slots[0],
760 struct btrfs_free_space_header);
761 btrfs_set_free_space_entries(leaf, header, entries);
762 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
763 btrfs_set_free_space_generation(leaf, header, trans->transid);
764 btrfs_mark_buffer_dirty(leaf);
765 btrfs_release_path(root, path);
771 invalidate_inode_pages2_range(inode->i_mapping, 0, index);
772 spin_lock(&block_group->lock);
773 block_group->disk_cache_state = BTRFS_DC_ERROR;
774 spin_unlock(&block_group->lock);
775 BTRFS_I(inode)->generation = 0;
778 btrfs_update_inode(trans, root, inode);
783 static inline unsigned long offset_to_bit(u64 bitmap_start, u64 sectorsize,
786 BUG_ON(offset < bitmap_start);
787 offset -= bitmap_start;
788 return (unsigned long)(div64_u64(offset, sectorsize));
791 static inline unsigned long bytes_to_bits(u64 bytes, u64 sectorsize)
793 return (unsigned long)(div64_u64(bytes, sectorsize));
796 static inline u64 offset_to_bitmap(struct btrfs_block_group_cache *block_group,
800 u64 bytes_per_bitmap;
802 bytes_per_bitmap = BITS_PER_BITMAP * block_group->sectorsize;
803 bitmap_start = offset - block_group->key.objectid;
804 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
805 bitmap_start *= bytes_per_bitmap;
806 bitmap_start += block_group->key.objectid;
811 static int tree_insert_offset(struct rb_root *root, u64 offset,
812 struct rb_node *node, int bitmap)
814 struct rb_node **p = &root->rb_node;
815 struct rb_node *parent = NULL;
816 struct btrfs_free_space *info;
820 info = rb_entry(parent, struct btrfs_free_space, offset_index);
822 if (offset < info->offset) {
824 } else if (offset > info->offset) {
828 * we could have a bitmap entry and an extent entry
829 * share the same offset. If this is the case, we want
830 * the extent entry to always be found first if we do a
831 * linear search through the tree, since we want to have
832 * the quickest allocation time, and allocating from an
833 * extent is faster than allocating from a bitmap. So
834 * if we're inserting a bitmap and we find an entry at
835 * this offset, we want to go right, or after this entry
836 * logically. If we are inserting an extent and we've
837 * found a bitmap, we want to go left, or before
841 WARN_ON(info->bitmap);
844 WARN_ON(!info->bitmap);
850 rb_link_node(node, parent, p);
851 rb_insert_color(node, root);
857 * searches the tree for the given offset.
859 * fuzzy - If this is set, then we are trying to make an allocation, and we just
860 * want a section that has at least bytes size and comes at or after the given
863 static struct btrfs_free_space *
864 tree_search_offset(struct btrfs_block_group_cache *block_group,
865 u64 offset, int bitmap_only, int fuzzy)
867 struct rb_node *n = block_group->free_space_offset.rb_node;
868 struct btrfs_free_space *entry, *prev = NULL;
870 /* find entry that is closest to the 'offset' */
877 entry = rb_entry(n, struct btrfs_free_space, offset_index);
880 if (offset < entry->offset)
882 else if (offset > entry->offset)
895 * bitmap entry and extent entry may share same offset,
896 * in that case, bitmap entry comes after extent entry.
901 entry = rb_entry(n, struct btrfs_free_space, offset_index);
902 if (entry->offset != offset)
905 WARN_ON(!entry->bitmap);
910 * if previous extent entry covers the offset,
911 * we should return it instead of the bitmap entry
913 n = &entry->offset_index;
918 prev = rb_entry(n, struct btrfs_free_space,
921 if (prev->offset + prev->bytes > offset)
933 /* find last entry before the 'offset' */
935 if (entry->offset > offset) {
936 n = rb_prev(&entry->offset_index);
938 entry = rb_entry(n, struct btrfs_free_space,
940 BUG_ON(entry->offset > offset);
950 n = &entry->offset_index;
955 prev = rb_entry(n, struct btrfs_free_space,
958 if (prev->offset + prev->bytes > offset)
963 if (entry->offset + BITS_PER_BITMAP *
964 block_group->sectorsize > offset)
966 } else if (entry->offset + entry->bytes > offset)
974 if (entry->offset + BITS_PER_BITMAP *
975 block_group->sectorsize > offset)
978 if (entry->offset + entry->bytes > offset)
982 n = rb_next(&entry->offset_index);
985 entry = rb_entry(n, struct btrfs_free_space, offset_index);
990 static void unlink_free_space(struct btrfs_block_group_cache *block_group,
991 struct btrfs_free_space *info)
993 rb_erase(&info->offset_index, &block_group->free_space_offset);
994 block_group->free_extents--;
995 block_group->free_space -= info->bytes;
998 static int link_free_space(struct btrfs_block_group_cache *block_group,
999 struct btrfs_free_space *info)
1003 BUG_ON(!info->bitmap && !info->bytes);
1004 ret = tree_insert_offset(&block_group->free_space_offset, info->offset,
1005 &info->offset_index, (info->bitmap != NULL));
1009 block_group->free_space += info->bytes;
1010 block_group->free_extents++;
1014 static void recalculate_thresholds(struct btrfs_block_group_cache *block_group)
1019 u64 size = block_group->key.offset;
1022 * The goal is to keep the total amount of memory used per 1gb of space
1023 * at or below 32k, so we need to adjust how much memory we allow to be
1024 * used by extent based free space tracking
1026 if (size < 1024 * 1024 * 1024)
1027 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1029 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1030 div64_u64(size, 1024 * 1024 * 1024);
1033 * we want to account for 1 more bitmap than what we have so we can make
1034 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1035 * we add more bitmaps.
1037 bitmap_bytes = (block_group->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1039 if (bitmap_bytes >= max_bytes) {
1040 block_group->extents_thresh = 0;
1045 * we want the extent entry threshold to always be at most 1/2 the maxw
1046 * bytes we can have, or whatever is less than that.
1048 extent_bytes = max_bytes - bitmap_bytes;
1049 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1051 block_group->extents_thresh =
1052 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1055 static void bitmap_clear_bits(struct btrfs_block_group_cache *block_group,
1056 struct btrfs_free_space *info, u64 offset,
1059 unsigned long start, end;
1062 start = offset_to_bit(info->offset, block_group->sectorsize, offset);
1063 end = start + bytes_to_bits(bytes, block_group->sectorsize);
1064 BUG_ON(end > BITS_PER_BITMAP);
1066 for (i = start; i < end; i++)
1067 clear_bit(i, info->bitmap);
1069 info->bytes -= bytes;
1070 block_group->free_space -= bytes;
1073 static void bitmap_set_bits(struct btrfs_block_group_cache *block_group,
1074 struct btrfs_free_space *info, u64 offset,
1077 unsigned long start, end;
1080 start = offset_to_bit(info->offset, block_group->sectorsize, offset);
1081 end = start + bytes_to_bits(bytes, block_group->sectorsize);
1082 BUG_ON(end > BITS_PER_BITMAP);
1084 for (i = start; i < end; i++)
1085 set_bit(i, info->bitmap);
1087 info->bytes += bytes;
1088 block_group->free_space += bytes;
1091 static int search_bitmap(struct btrfs_block_group_cache *block_group,
1092 struct btrfs_free_space *bitmap_info, u64 *offset,
1095 unsigned long found_bits = 0;
1096 unsigned long bits, i;
1097 unsigned long next_zero;
1099 i = offset_to_bit(bitmap_info->offset, block_group->sectorsize,
1100 max_t(u64, *offset, bitmap_info->offset));
1101 bits = bytes_to_bits(*bytes, block_group->sectorsize);
1103 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1104 i < BITS_PER_BITMAP;
1105 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1106 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1107 BITS_PER_BITMAP, i);
1108 if ((next_zero - i) >= bits) {
1109 found_bits = next_zero - i;
1116 *offset = (u64)(i * block_group->sectorsize) +
1117 bitmap_info->offset;
1118 *bytes = (u64)(found_bits) * block_group->sectorsize;
1125 static struct btrfs_free_space *find_free_space(struct btrfs_block_group_cache
1126 *block_group, u64 *offset,
1127 u64 *bytes, int debug)
1129 struct btrfs_free_space *entry;
1130 struct rb_node *node;
1133 if (!block_group->free_space_offset.rb_node)
1136 entry = tree_search_offset(block_group,
1137 offset_to_bitmap(block_group, *offset),
1142 for (node = &entry->offset_index; node; node = rb_next(node)) {
1143 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1144 if (entry->bytes < *bytes)
1147 if (entry->bitmap) {
1148 ret = search_bitmap(block_group, entry, offset, bytes);
1154 *offset = entry->offset;
1155 *bytes = entry->bytes;
1162 static void add_new_bitmap(struct btrfs_block_group_cache *block_group,
1163 struct btrfs_free_space *info, u64 offset)
1165 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1166 int max_bitmaps = (int)div64_u64(block_group->key.offset +
1167 bytes_per_bg - 1, bytes_per_bg);
1168 BUG_ON(block_group->total_bitmaps >= max_bitmaps);
1170 info->offset = offset_to_bitmap(block_group, offset);
1172 link_free_space(block_group, info);
1173 block_group->total_bitmaps++;
1175 recalculate_thresholds(block_group);
1178 static void free_bitmap(struct btrfs_block_group_cache *block_group,
1179 struct btrfs_free_space *bitmap_info)
1181 unlink_free_space(block_group, bitmap_info);
1182 kfree(bitmap_info->bitmap);
1184 block_group->total_bitmaps--;
1185 recalculate_thresholds(block_group);
1188 static noinline int remove_from_bitmap(struct btrfs_block_group_cache *block_group,
1189 struct btrfs_free_space *bitmap_info,
1190 u64 *offset, u64 *bytes)
1193 u64 search_start, search_bytes;
1197 end = bitmap_info->offset +
1198 (u64)(BITS_PER_BITMAP * block_group->sectorsize) - 1;
1201 * XXX - this can go away after a few releases.
1203 * since the only user of btrfs_remove_free_space is the tree logging
1204 * stuff, and the only way to test that is under crash conditions, we
1205 * want to have this debug stuff here just in case somethings not
1206 * working. Search the bitmap for the space we are trying to use to
1207 * make sure its actually there. If its not there then we need to stop
1208 * because something has gone wrong.
1210 search_start = *offset;
1211 search_bytes = *bytes;
1212 ret = search_bitmap(block_group, bitmap_info, &search_start,
1214 BUG_ON(ret < 0 || search_start != *offset);
1216 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1217 bitmap_clear_bits(block_group, bitmap_info, *offset,
1219 *bytes -= end - *offset + 1;
1221 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1222 bitmap_clear_bits(block_group, bitmap_info, *offset, *bytes);
1227 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1228 if (!bitmap_info->bytes)
1229 free_bitmap(block_group, bitmap_info);
1232 * no entry after this bitmap, but we still have bytes to
1233 * remove, so something has gone wrong.
1238 bitmap_info = rb_entry(next, struct btrfs_free_space,
1242 * if the next entry isn't a bitmap we need to return to let the
1243 * extent stuff do its work.
1245 if (!bitmap_info->bitmap)
1249 * Ok the next item is a bitmap, but it may not actually hold
1250 * the information for the rest of this free space stuff, so
1251 * look for it, and if we don't find it return so we can try
1252 * everything over again.
1254 search_start = *offset;
1255 search_bytes = *bytes;
1256 ret = search_bitmap(block_group, bitmap_info, &search_start,
1258 if (ret < 0 || search_start != *offset)
1262 } else if (!bitmap_info->bytes)
1263 free_bitmap(block_group, bitmap_info);
1268 static int insert_into_bitmap(struct btrfs_block_group_cache *block_group,
1269 struct btrfs_free_space *info)
1271 struct btrfs_free_space *bitmap_info;
1273 u64 bytes, offset, end;
1277 * If we are below the extents threshold then we can add this as an
1278 * extent, and don't have to deal with the bitmap
1280 if (block_group->free_extents < block_group->extents_thresh &&
1281 info->bytes > block_group->sectorsize * 4)
1285 * some block groups are so tiny they can't be enveloped by a bitmap, so
1286 * don't even bother to create a bitmap for this
1288 if (BITS_PER_BITMAP * block_group->sectorsize >
1289 block_group->key.offset)
1292 bytes = info->bytes;
1293 offset = info->offset;
1296 bitmap_info = tree_search_offset(block_group,
1297 offset_to_bitmap(block_group, offset),
1304 end = bitmap_info->offset +
1305 (u64)(BITS_PER_BITMAP * block_group->sectorsize);
1307 if (offset >= bitmap_info->offset && offset + bytes > end) {
1308 bitmap_set_bits(block_group, bitmap_info, offset,
1310 bytes -= end - offset;
1313 } else if (offset >= bitmap_info->offset && offset + bytes <= end) {
1314 bitmap_set_bits(block_group, bitmap_info, offset, bytes);
1327 if (info && info->bitmap) {
1328 add_new_bitmap(block_group, info, offset);
1333 spin_unlock(&block_group->tree_lock);
1335 /* no pre-allocated info, allocate a new one */
1337 info = kzalloc(sizeof(struct btrfs_free_space),
1340 spin_lock(&block_group->tree_lock);
1346 /* allocate the bitmap */
1347 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1348 spin_lock(&block_group->tree_lock);
1349 if (!info->bitmap) {
1359 kfree(info->bitmap);
1366 int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
1367 u64 offset, u64 bytes)
1369 struct btrfs_free_space *right_info = NULL;
1370 struct btrfs_free_space *left_info = NULL;
1371 struct btrfs_free_space *info = NULL;
1374 info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
1378 info->offset = offset;
1379 info->bytes = bytes;
1381 spin_lock(&block_group->tree_lock);
1384 * first we want to see if there is free space adjacent to the range we
1385 * are adding, if there is remove that struct and add a new one to
1386 * cover the entire range
1388 right_info = tree_search_offset(block_group, offset + bytes, 0, 0);
1389 if (right_info && rb_prev(&right_info->offset_index))
1390 left_info = rb_entry(rb_prev(&right_info->offset_index),
1391 struct btrfs_free_space, offset_index);
1393 left_info = tree_search_offset(block_group, offset - 1, 0, 0);
1396 * If there was no extent directly to the left or right of this new
1397 * extent then we know we're going to have to allocate a new extent, so
1398 * before we do that see if we need to drop this into a bitmap
1400 if ((!left_info || left_info->bitmap) &&
1401 (!right_info || right_info->bitmap)) {
1402 ret = insert_into_bitmap(block_group, info);
1412 if (right_info && !right_info->bitmap) {
1413 unlink_free_space(block_group, right_info);
1414 info->bytes += right_info->bytes;
1418 if (left_info && !left_info->bitmap &&
1419 left_info->offset + left_info->bytes == offset) {
1420 unlink_free_space(block_group, left_info);
1421 info->offset = left_info->offset;
1422 info->bytes += left_info->bytes;
1426 ret = link_free_space(block_group, info);
1430 spin_unlock(&block_group->tree_lock);
1433 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1434 BUG_ON(ret == -EEXIST);
1440 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1441 u64 offset, u64 bytes)
1443 struct btrfs_free_space *info;
1444 struct btrfs_free_space *next_info = NULL;
1447 spin_lock(&block_group->tree_lock);
1450 info = tree_search_offset(block_group, offset, 0, 0);
1453 * oops didn't find an extent that matched the space we wanted
1454 * to remove, look for a bitmap instead
1456 info = tree_search_offset(block_group,
1457 offset_to_bitmap(block_group, offset),
1465 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1467 next_info = rb_entry(rb_next(&info->offset_index),
1468 struct btrfs_free_space,
1471 if (next_info->bitmap)
1472 end = next_info->offset + BITS_PER_BITMAP *
1473 block_group->sectorsize - 1;
1475 end = next_info->offset + next_info->bytes;
1477 if (next_info->bytes < bytes ||
1478 next_info->offset > offset || offset > end) {
1479 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1480 " trying to use %llu\n",
1481 (unsigned long long)info->offset,
1482 (unsigned long long)info->bytes,
1483 (unsigned long long)bytes);
1492 if (info->bytes == bytes) {
1493 unlink_free_space(block_group, info);
1495 kfree(info->bitmap);
1496 block_group->total_bitmaps--;
1502 if (!info->bitmap && info->offset == offset) {
1503 unlink_free_space(block_group, info);
1504 info->offset += bytes;
1505 info->bytes -= bytes;
1506 link_free_space(block_group, info);
1510 if (!info->bitmap && info->offset <= offset &&
1511 info->offset + info->bytes >= offset + bytes) {
1512 u64 old_start = info->offset;
1514 * we're freeing space in the middle of the info,
1515 * this can happen during tree log replay
1517 * first unlink the old info and then
1518 * insert it again after the hole we're creating
1520 unlink_free_space(block_group, info);
1521 if (offset + bytes < info->offset + info->bytes) {
1522 u64 old_end = info->offset + info->bytes;
1524 info->offset = offset + bytes;
1525 info->bytes = old_end - info->offset;
1526 ret = link_free_space(block_group, info);
1531 /* the hole we're creating ends at the end
1532 * of the info struct, just free the info
1536 spin_unlock(&block_group->tree_lock);
1538 /* step two, insert a new info struct to cover
1539 * anything before the hole
1541 ret = btrfs_add_free_space(block_group, old_start,
1542 offset - old_start);
1547 ret = remove_from_bitmap(block_group, info, &offset, &bytes);
1552 spin_unlock(&block_group->tree_lock);
1557 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1560 struct btrfs_free_space *info;
1564 for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) {
1565 info = rb_entry(n, struct btrfs_free_space, offset_index);
1566 if (info->bytes >= bytes)
1568 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1569 (unsigned long long)info->offset,
1570 (unsigned long long)info->bytes,
1571 (info->bitmap) ? "yes" : "no");
1573 printk(KERN_INFO "block group has cluster?: %s\n",
1574 list_empty(&block_group->cluster_list) ? "no" : "yes");
1575 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1579 u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group)
1581 struct btrfs_free_space *info;
1585 for (n = rb_first(&block_group->free_space_offset); n;
1587 info = rb_entry(n, struct btrfs_free_space, offset_index);
1595 * for a given cluster, put all of its extents back into the free
1596 * space cache. If the block group passed doesn't match the block group
1597 * pointed to by the cluster, someone else raced in and freed the
1598 * cluster already. In that case, we just return without changing anything
1601 __btrfs_return_cluster_to_free_space(
1602 struct btrfs_block_group_cache *block_group,
1603 struct btrfs_free_cluster *cluster)
1605 struct btrfs_free_space *entry;
1606 struct rb_node *node;
1609 spin_lock(&cluster->lock);
1610 if (cluster->block_group != block_group)
1613 bitmap = cluster->points_to_bitmap;
1614 cluster->block_group = NULL;
1615 cluster->window_start = 0;
1616 list_del_init(&cluster->block_group_list);
1617 cluster->points_to_bitmap = false;
1622 node = rb_first(&cluster->root);
1624 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1625 node = rb_next(&entry->offset_index);
1626 rb_erase(&entry->offset_index, &cluster->root);
1627 BUG_ON(entry->bitmap);
1628 tree_insert_offset(&block_group->free_space_offset,
1629 entry->offset, &entry->offset_index, 0);
1631 cluster->root = RB_ROOT;
1634 spin_unlock(&cluster->lock);
1635 btrfs_put_block_group(block_group);
1639 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
1641 struct btrfs_free_space *info;
1642 struct rb_node *node;
1643 struct btrfs_free_cluster *cluster;
1644 struct list_head *head;
1646 spin_lock(&block_group->tree_lock);
1647 while ((head = block_group->cluster_list.next) !=
1648 &block_group->cluster_list) {
1649 cluster = list_entry(head, struct btrfs_free_cluster,
1652 WARN_ON(cluster->block_group != block_group);
1653 __btrfs_return_cluster_to_free_space(block_group, cluster);
1654 if (need_resched()) {
1655 spin_unlock(&block_group->tree_lock);
1657 spin_lock(&block_group->tree_lock);
1661 while ((node = rb_last(&block_group->free_space_offset)) != NULL) {
1662 info = rb_entry(node, struct btrfs_free_space, offset_index);
1663 unlink_free_space(block_group, info);
1665 kfree(info->bitmap);
1667 if (need_resched()) {
1668 spin_unlock(&block_group->tree_lock);
1670 spin_lock(&block_group->tree_lock);
1674 spin_unlock(&block_group->tree_lock);
1677 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
1678 u64 offset, u64 bytes, u64 empty_size)
1680 struct btrfs_free_space *entry = NULL;
1681 u64 bytes_search = bytes + empty_size;
1684 spin_lock(&block_group->tree_lock);
1685 entry = find_free_space(block_group, &offset, &bytes_search, 0);
1690 if (entry->bitmap) {
1691 bitmap_clear_bits(block_group, entry, offset, bytes);
1693 free_bitmap(block_group, entry);
1695 unlink_free_space(block_group, entry);
1696 entry->offset += bytes;
1697 entry->bytes -= bytes;
1701 link_free_space(block_group, entry);
1705 spin_unlock(&block_group->tree_lock);
1711 * given a cluster, put all of its extents back into the free space
1712 * cache. If a block group is passed, this function will only free
1713 * a cluster that belongs to the passed block group.
1715 * Otherwise, it'll get a reference on the block group pointed to by the
1716 * cluster and remove the cluster from it.
1718 int btrfs_return_cluster_to_free_space(
1719 struct btrfs_block_group_cache *block_group,
1720 struct btrfs_free_cluster *cluster)
1724 /* first, get a safe pointer to the block group */
1725 spin_lock(&cluster->lock);
1727 block_group = cluster->block_group;
1729 spin_unlock(&cluster->lock);
1732 } else if (cluster->block_group != block_group) {
1733 /* someone else has already freed it don't redo their work */
1734 spin_unlock(&cluster->lock);
1737 atomic_inc(&block_group->count);
1738 spin_unlock(&cluster->lock);
1740 /* now return any extents the cluster had on it */
1741 spin_lock(&block_group->tree_lock);
1742 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
1743 spin_unlock(&block_group->tree_lock);
1745 /* finally drop our ref */
1746 btrfs_put_block_group(block_group);
1750 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
1751 struct btrfs_free_cluster *cluster,
1752 u64 bytes, u64 min_start)
1754 struct btrfs_free_space *entry;
1756 u64 search_start = cluster->window_start;
1757 u64 search_bytes = bytes;
1760 spin_lock(&block_group->tree_lock);
1761 spin_lock(&cluster->lock);
1763 if (!cluster->points_to_bitmap)
1766 if (cluster->block_group != block_group)
1770 * search_start is the beginning of the bitmap, but at some point it may
1771 * be a good idea to point to the actual start of the free area in the
1772 * bitmap, so do the offset_to_bitmap trick anyway, and set bitmap_only
1773 * to 1 to make sure we get the bitmap entry
1775 entry = tree_search_offset(block_group,
1776 offset_to_bitmap(block_group, search_start),
1778 if (!entry || !entry->bitmap)
1781 search_start = min_start;
1782 search_bytes = bytes;
1784 err = search_bitmap(block_group, entry, &search_start,
1790 bitmap_clear_bits(block_group, entry, ret, bytes);
1791 if (entry->bytes == 0)
1792 free_bitmap(block_group, entry);
1794 spin_unlock(&cluster->lock);
1795 spin_unlock(&block_group->tree_lock);
1801 * given a cluster, try to allocate 'bytes' from it, returns 0
1802 * if it couldn't find anything suitably large, or a logical disk offset
1803 * if things worked out
1805 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
1806 struct btrfs_free_cluster *cluster, u64 bytes,
1809 struct btrfs_free_space *entry = NULL;
1810 struct rb_node *node;
1813 if (cluster->points_to_bitmap)
1814 return btrfs_alloc_from_bitmap(block_group, cluster, bytes,
1817 spin_lock(&cluster->lock);
1818 if (bytes > cluster->max_size)
1821 if (cluster->block_group != block_group)
1824 node = rb_first(&cluster->root);
1828 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1831 if (entry->bytes < bytes || entry->offset < min_start) {
1832 struct rb_node *node;
1834 node = rb_next(&entry->offset_index);
1837 entry = rb_entry(node, struct btrfs_free_space,
1841 ret = entry->offset;
1843 entry->offset += bytes;
1844 entry->bytes -= bytes;
1846 if (entry->bytes == 0) {
1847 rb_erase(&entry->offset_index, &cluster->root);
1853 spin_unlock(&cluster->lock);
1858 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
1859 struct btrfs_free_space *entry,
1860 struct btrfs_free_cluster *cluster,
1861 u64 offset, u64 bytes, u64 min_bytes)
1863 unsigned long next_zero;
1865 unsigned long search_bits;
1866 unsigned long total_bits;
1867 unsigned long found_bits;
1868 unsigned long start = 0;
1869 unsigned long total_found = 0;
1872 i = offset_to_bit(entry->offset, block_group->sectorsize,
1873 max_t(u64, offset, entry->offset));
1874 search_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
1875 total_bits = bytes_to_bits(bytes, block_group->sectorsize);
1879 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
1880 i < BITS_PER_BITMAP;
1881 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
1882 next_zero = find_next_zero_bit(entry->bitmap,
1883 BITS_PER_BITMAP, i);
1884 if (next_zero - i >= search_bits) {
1885 found_bits = next_zero - i;
1899 total_found += found_bits;
1901 if (cluster->max_size < found_bits * block_group->sectorsize)
1902 cluster->max_size = found_bits * block_group->sectorsize;
1904 if (total_found < total_bits) {
1905 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
1906 if (i - start > total_bits * 2) {
1908 cluster->max_size = 0;
1914 cluster->window_start = start * block_group->sectorsize +
1916 cluster->points_to_bitmap = true;
1922 * here we try to find a cluster of blocks in a block group. The goal
1923 * is to find at least bytes free and up to empty_size + bytes free.
1924 * We might not find them all in one contiguous area.
1926 * returns zero and sets up cluster if things worked out, otherwise
1927 * it returns -enospc
1929 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
1930 struct btrfs_root *root,
1931 struct btrfs_block_group_cache *block_group,
1932 struct btrfs_free_cluster *cluster,
1933 u64 offset, u64 bytes, u64 empty_size)
1935 struct btrfs_free_space *entry = NULL;
1936 struct rb_node *node;
1937 struct btrfs_free_space *next;
1938 struct btrfs_free_space *last = NULL;
1943 bool found_bitmap = false;
1946 /* for metadata, allow allocates with more holes */
1947 if (btrfs_test_opt(root, SSD_SPREAD)) {
1948 min_bytes = bytes + empty_size;
1949 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
1951 * we want to do larger allocations when we are
1952 * flushing out the delayed refs, it helps prevent
1953 * making more work as we go along.
1955 if (trans->transaction->delayed_refs.flushing)
1956 min_bytes = max(bytes, (bytes + empty_size) >> 1);
1958 min_bytes = max(bytes, (bytes + empty_size) >> 4);
1960 min_bytes = max(bytes, (bytes + empty_size) >> 2);
1962 spin_lock(&block_group->tree_lock);
1963 spin_lock(&cluster->lock);
1965 /* someone already found a cluster, hooray */
1966 if (cluster->block_group) {
1971 entry = tree_search_offset(block_group, offset, found_bitmap, 1);
1978 * If found_bitmap is true, we exhausted our search for extent entries,
1979 * and we just want to search all of the bitmaps that we can find, and
1980 * ignore any extent entries we find.
1982 while (entry->bitmap || found_bitmap ||
1983 (!entry->bitmap && entry->bytes < min_bytes)) {
1984 struct rb_node *node = rb_next(&entry->offset_index);
1986 if (entry->bitmap && entry->bytes > bytes + empty_size) {
1987 ret = btrfs_bitmap_cluster(block_group, entry, cluster,
1988 offset, bytes + empty_size,
1998 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2002 * We already searched all the extent entries from the passed in offset
2003 * to the end and didn't find enough space for the cluster, and we also
2004 * didn't find any bitmaps that met our criteria, just go ahead and exit
2011 cluster->points_to_bitmap = false;
2012 window_start = entry->offset;
2013 window_free = entry->bytes;
2015 max_extent = entry->bytes;
2018 /* out window is just right, lets fill it */
2019 if (window_free >= bytes + empty_size)
2022 node = rb_next(&last->offset_index);
2029 next = rb_entry(node, struct btrfs_free_space, offset_index);
2032 * we found a bitmap, so if this search doesn't result in a
2033 * cluster, we know to go and search again for the bitmaps and
2034 * start looking for space there
2038 offset = next->offset;
2039 found_bitmap = true;
2045 * we haven't filled the empty size and the window is
2046 * very large. reset and try again
2048 if (next->offset - (last->offset + last->bytes) > 128 * 1024 ||
2049 next->offset - window_start > (bytes + empty_size) * 2) {
2051 window_start = entry->offset;
2052 window_free = entry->bytes;
2054 max_extent = entry->bytes;
2057 window_free += next->bytes;
2058 if (entry->bytes > max_extent)
2059 max_extent = entry->bytes;
2063 cluster->window_start = entry->offset;
2066 * now we've found our entries, pull them out of the free space
2067 * cache and put them into the cluster rbtree
2069 * The cluster includes an rbtree, but only uses the offset index
2070 * of each free space cache entry.
2073 node = rb_next(&entry->offset_index);
2074 if (entry->bitmap && node) {
2075 entry = rb_entry(node, struct btrfs_free_space,
2078 } else if (entry->bitmap && !node) {
2082 rb_erase(&entry->offset_index, &block_group->free_space_offset);
2083 ret = tree_insert_offset(&cluster->root, entry->offset,
2084 &entry->offset_index, 0);
2087 if (!node || entry == last)
2090 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2093 cluster->max_size = max_extent;
2096 atomic_inc(&block_group->count);
2097 list_add_tail(&cluster->block_group_list, &block_group->cluster_list);
2098 cluster->block_group = block_group;
2100 spin_unlock(&cluster->lock);
2101 spin_unlock(&block_group->tree_lock);
2107 * simple code to zero out a cluster
2109 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2111 spin_lock_init(&cluster->lock);
2112 spin_lock_init(&cluster->refill_lock);
2113 cluster->root = RB_ROOT;
2114 cluster->max_size = 0;
2115 cluster->points_to_bitmap = false;
2116 INIT_LIST_HEAD(&cluster->block_group_list);
2117 cluster->block_group = NULL;