1 #include <linux/module.h>
4 #include "print-tree.h"
5 #include "transaction.h"
7 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
8 *orig_root, u64 num_blocks, u64 search_start, u64
9 search_end, struct btrfs_key *ins);
10 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
11 btrfs_root *extent_root);
12 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
13 btrfs_root *extent_root);
15 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
16 struct btrfs_root *root,
17 u64 blocknr, u64 num_blocks)
19 struct btrfs_path *path;
23 struct btrfs_extent_item *item;
27 find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1,
29 path = btrfs_alloc_path();
31 btrfs_init_path(path);
32 key.objectid = blocknr;
34 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
35 key.offset = num_blocks;
36 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
41 l = btrfs_buffer_leaf(path->nodes[0]);
42 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
43 refs = btrfs_extent_refs(item);
44 btrfs_set_extent_refs(item, refs + 1);
45 btrfs_mark_buffer_dirty(path->nodes[0]);
47 btrfs_release_path(root->fs_info->extent_root, path);
48 btrfs_free_path(path);
49 finish_current_insert(trans, root->fs_info->extent_root);
50 del_pending_extents(trans, root->fs_info->extent_root);
54 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
55 struct btrfs_root *root, u64 blocknr,
56 u64 num_blocks, u32 *refs)
58 struct btrfs_path *path;
62 struct btrfs_extent_item *item;
64 path = btrfs_alloc_path();
65 btrfs_init_path(path);
66 key.objectid = blocknr;
67 key.offset = num_blocks;
69 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
70 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
74 l = btrfs_buffer_leaf(path->nodes[0]);
75 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
76 *refs = btrfs_extent_refs(item);
77 btrfs_release_path(root->fs_info->extent_root, path);
78 btrfs_free_path(path);
82 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
83 struct btrfs_root *root)
85 return btrfs_inc_extent_ref(trans, root, bh_blocknr(root->node), 1);
88 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
89 struct buffer_head *buf)
92 struct btrfs_node *buf_node;
93 struct btrfs_leaf *buf_leaf;
94 struct btrfs_disk_key *key;
95 struct btrfs_file_extent_item *fi;
102 buf_node = btrfs_buffer_node(buf);
103 leaf = btrfs_is_leaf(buf_node);
104 buf_leaf = btrfs_buffer_leaf(buf);
105 for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
107 key = &buf_leaf->items[i].key;
108 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
110 fi = btrfs_item_ptr(buf_leaf, i,
111 struct btrfs_file_extent_item);
112 ret = btrfs_inc_extent_ref(trans, root,
113 btrfs_file_extent_disk_blocknr(fi),
114 btrfs_file_extent_disk_num_blocks(fi));
117 blocknr = btrfs_node_blockptr(buf_node, i);
118 ret = btrfs_inc_extent_ref(trans, root, blocknr, 1);
125 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
128 unsigned long gang[8];
132 struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
135 ret = find_first_radix_bit(pinned_radix, gang,
141 for (i = 0; i < ret; i++) {
142 clear_radix_bit(pinned_radix, gang[i]);
145 if (root->fs_info->last_insert.objectid > first)
146 root->fs_info->last_insert.objectid = first;
147 root->fs_info->last_insert.offset = 0;
151 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
152 btrfs_root *extent_root)
154 struct btrfs_key ins;
155 struct btrfs_extent_item extent_item;
158 u64 super_blocks_used;
159 struct btrfs_fs_info *info = extent_root->fs_info;
161 btrfs_set_extent_refs(&extent_item, 1);
164 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
166 for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) {
167 ins.objectid = extent_root->fs_info->current_insert.objectid +
169 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
170 btrfs_set_super_blocks_used(info->disk_super,
171 super_blocks_used + 1);
172 ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
173 sizeof(extent_item));
176 extent_root->fs_info->current_insert.offset = 0;
180 static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
183 struct btrfs_header *header;
184 struct buffer_head *bh;
187 bh = btrfs_find_tree_block(root, blocknr);
189 if (buffer_uptodate(bh)) {
191 root->fs_info->running_transaction->transid;
192 header = btrfs_buffer_header(bh);
193 if (btrfs_header_generation(header) ==
195 btrfs_block_release(root, bh);
199 btrfs_block_release(root, bh);
201 err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
203 err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
210 * remove an extent from the root, returns 0 on success
212 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
213 *root, u64 blocknr, u64 num_blocks, int pin)
215 struct btrfs_path *path;
216 struct btrfs_key key;
217 struct btrfs_fs_info *info = root->fs_info;
218 struct btrfs_root *extent_root = info->extent_root;
220 struct btrfs_extent_item *ei;
221 struct btrfs_key ins;
224 key.objectid = blocknr;
226 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
227 key.offset = num_blocks;
229 find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
230 path = btrfs_alloc_path();
232 btrfs_init_path(path);
234 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
236 printk("failed to find %Lu\n", key.objectid);
237 btrfs_print_tree(extent_root, extent_root->node);
238 printk("failed to find %Lu\n", key.objectid);
241 ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
242 struct btrfs_extent_item);
243 BUG_ON(ei->refs == 0);
244 refs = btrfs_extent_refs(ei) - 1;
245 btrfs_set_extent_refs(ei, refs);
246 btrfs_mark_buffer_dirty(path->nodes[0]);
248 u64 super_blocks_used;
251 ret = pin_down_block(root, blocknr, 0);
255 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
256 btrfs_set_super_blocks_used(info->disk_super,
257 super_blocks_used - num_blocks);
258 ret = btrfs_del_item(trans, extent_root, path);
262 btrfs_release_path(extent_root, path);
263 btrfs_free_path(path);
264 finish_current_insert(trans, extent_root);
269 * find all the blocks marked as pending in the radix tree and remove
270 * them from the extent map
272 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
273 btrfs_root *extent_root)
278 unsigned long gang[4];
280 struct radix_tree_root *pending_radix;
281 struct radix_tree_root *pinned_radix;
283 pending_radix = &extent_root->fs_info->pending_del_radix;
284 pinned_radix = &extent_root->fs_info->pinned_radix;
287 ret = find_first_radix_bit(pending_radix, gang,
291 for (i = 0; i < ret; i++) {
292 wret = set_radix_bit(pinned_radix, gang[i]);
294 wret = clear_radix_bit(pending_radix, gang[i]);
296 wret = __free_extent(trans, extent_root,
306 * remove an extent from the root, returns 0 on success
308 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
309 *root, u64 blocknr, u64 num_blocks, int pin)
311 struct btrfs_root *extent_root = root->fs_info->extent_root;
315 if (root == extent_root) {
316 pin_down_block(root, blocknr, 1);
319 ret = __free_extent(trans, root, blocknr, num_blocks, pin);
320 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
321 return ret ? ret : pending_ret;
325 * walks the btree of allocated extents and find a hole of a given size.
326 * The key ins is changed to record the hole:
327 * ins->objectid == block start
328 * ins->flags = BTRFS_EXTENT_ITEM_KEY
329 * ins->offset == number of blocks
330 * Any available blocks before search_start are skipped.
332 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
333 *orig_root, u64 num_blocks, u64 search_start, u64
334 search_end, struct btrfs_key *ins)
336 struct btrfs_path *path;
337 struct btrfs_key key;
344 struct btrfs_leaf *l;
345 struct btrfs_root * root = orig_root->fs_info->extent_root;
346 int total_needed = num_blocks;
349 path = btrfs_alloc_path();
351 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
353 level = btrfs_header_level(btrfs_buffer_header(root->node));
354 total_needed += (level + 1) * 3;
355 if (root->fs_info->last_insert.objectid == 0 && search_end == (u64)-1) {
356 struct btrfs_disk_key *last_key;
357 btrfs_init_path(path);
358 ins->objectid = (u64)-1;
359 ins->offset = (u64)-1;
360 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
364 if (path->slots[0] > 0)
366 l = btrfs_buffer_leaf(path->nodes[0]);
367 last_key = &l->items[path->slots[0]].key;
368 search_start = btrfs_disk_key_objectid(last_key);
370 if (root->fs_info->last_insert.objectid > search_start)
371 search_start = root->fs_info->last_insert.objectid;
374 btrfs_init_path(path);
375 ins->objectid = search_start;
378 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
382 if (path->slots[0] > 0)
386 l = btrfs_buffer_leaf(path->nodes[0]);
387 slot = path->slots[0];
388 if (slot >= btrfs_header_nritems(&l->header)) {
389 ret = btrfs_next_leaf(root, path);
395 ins->objectid = search_start;
396 ins->offset = (u64)-1;
400 ins->objectid = last_block > search_start ?
401 last_block : search_start;
402 ins->offset = (u64)-1;
405 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
406 if (key.objectid >= search_start) {
408 if (last_block < search_start)
409 last_block = search_start;
410 hole_size = key.objectid - last_block;
411 if (hole_size > total_needed) {
412 ins->objectid = last_block;
413 ins->offset = hole_size;
419 last_block = key.objectid + key.offset;
424 /* we have to make sure we didn't find an extent that has already
425 * been allocated by the map tree or the original allocation
427 btrfs_release_path(root, path);
428 BUG_ON(ins->objectid < search_start);
429 for (test_block = ins->objectid;
430 test_block < ins->objectid + total_needed; test_block++) {
431 if (test_radix_bit(&root->fs_info->pinned_radix,
433 search_start = test_block + 1;
437 BUG_ON(root->fs_info->current_insert.offset);
438 root->fs_info->current_insert.offset = total_needed - num_blocks;
439 root->fs_info->current_insert.objectid = ins->objectid + num_blocks;
440 root->fs_info->current_insert.flags = 0;
441 root->fs_info->last_insert.objectid = ins->objectid;
442 ins->offset = num_blocks;
443 btrfs_free_path(path);
446 btrfs_release_path(root, path);
447 btrfs_free_path(path);
452 * finds a free extent and does all the dirty work required for allocation
453 * returns the key for the extent through ins, and a tree buffer for
454 * the first block of the extent through buf.
456 * returns 0 if everything worked, non-zero otherwise.
458 int btrfs_alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
459 *root, u64 num_blocks, u64 search_start, u64
460 search_end, struct btrfs_key *ins)
464 u64 super_blocks_used;
465 struct btrfs_fs_info *info = root->fs_info;
466 struct btrfs_root *extent_root = info->extent_root;
467 struct btrfs_extent_item extent_item;
469 btrfs_set_extent_refs(&extent_item, 1);
471 if (root == extent_root) {
472 BUG_ON(extent_root->fs_info->current_insert.offset == 0);
473 BUG_ON(num_blocks != 1);
474 BUG_ON(extent_root->fs_info->current_insert.flags ==
475 extent_root->fs_info->current_insert.offset);
477 ins->objectid = extent_root->fs_info->current_insert.objectid +
478 extent_root->fs_info->current_insert.flags++;
481 ret = find_free_extent(trans, root, num_blocks, search_start,
486 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
487 btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
489 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
490 sizeof(extent_item));
492 finish_current_insert(trans, extent_root);
493 pending_ret = del_pending_extents(trans, extent_root);
502 * helper function to allocate a block for a given tree
503 * returns the tree buffer or NULL.
505 struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
506 struct btrfs_root *root)
508 struct btrfs_key ins;
510 struct buffer_head *buf;
512 ret = btrfs_alloc_extent(trans, root, 1, 0, (unsigned long)-1, &ins);
517 buf = btrfs_find_create_tree_block(root, ins.objectid);
518 set_buffer_uptodate(buf);
522 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
523 struct btrfs_root *root, struct buffer_head *cur)
525 struct btrfs_disk_key *key;
526 struct btrfs_leaf *leaf;
527 struct btrfs_file_extent_item *fi;
532 BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
533 leaf = btrfs_buffer_leaf(cur);
534 nritems = btrfs_header_nritems(&leaf->header);
535 for (i = 0; i < nritems; i++) {
536 key = &leaf->items[i].key;
537 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
539 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
541 * FIXME make sure to insert a trans record that
542 * repeats the snapshot del on crash
544 ret = btrfs_free_extent(trans, root,
545 btrfs_file_extent_disk_blocknr(fi),
546 btrfs_file_extent_disk_num_blocks(fi),
554 * helper function for drop_snapshot, this walks down the tree dropping ref
557 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
558 *root, struct btrfs_path *path, int *level)
560 struct buffer_head *next;
561 struct buffer_head *cur;
567 WARN_ON(*level >= BTRFS_MAX_LEVEL);
568 ret = lookup_extent_ref(trans, root, bh_blocknr(path->nodes[*level]),
574 * walk down to the last node level and free all the leaves
578 WARN_ON(*level >= BTRFS_MAX_LEVEL);
579 cur = path->nodes[*level];
580 if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
582 if (path->slots[*level] >=
583 btrfs_header_nritems(btrfs_buffer_header(cur)))
586 ret = drop_leaf_ref(trans, root, cur);
590 blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
591 path->slots[*level]);
592 ret = lookup_extent_ref(trans, root, blocknr, 1, &refs);
595 path->slots[*level]++;
596 ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
600 next = read_tree_block(root, blocknr);
601 WARN_ON(*level <= 0);
602 if (path->nodes[*level-1])
603 btrfs_block_release(root, path->nodes[*level-1]);
604 path->nodes[*level-1] = next;
605 *level = btrfs_header_level(btrfs_buffer_header(next));
606 path->slots[*level] = 0;
610 WARN_ON(*level >= BTRFS_MAX_LEVEL);
611 ret = btrfs_free_extent(trans, root,
612 bh_blocknr(path->nodes[*level]), 1, 1);
613 btrfs_block_release(root, path->nodes[*level]);
614 path->nodes[*level] = NULL;
621 * helper for dropping snapshots. This walks back up the tree in the path
622 * to find the first node higher up where we haven't yet gone through
625 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
626 *root, struct btrfs_path *path, int *level)
631 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
632 slot = path->slots[i];
633 if (slot < btrfs_header_nritems(
634 btrfs_buffer_header(path->nodes[i])) - 1) {
639 ret = btrfs_free_extent(trans, root,
640 bh_blocknr(path->nodes[*level]),
643 btrfs_block_release(root, path->nodes[*level]);
644 path->nodes[*level] = NULL;
652 * drop the reference count on the tree rooted at 'snap'. This traverses
653 * the tree freeing any blocks that have a ref count of zero after being
656 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
657 *root, struct buffer_head *snap)
662 struct btrfs_path *path;
666 path = btrfs_alloc_path();
668 btrfs_init_path(path);
670 level = btrfs_header_level(btrfs_buffer_header(snap));
672 path->nodes[level] = snap;
673 path->slots[level] = 0;
675 wret = walk_down_tree(trans, root, path, &level);
681 wret = walk_up_tree(trans, root, path, &level);
687 for (i = 0; i <= orig_level; i++) {
688 if (path->nodes[i]) {
689 btrfs_block_release(root, path->nodes[i]);
692 btrfs_free_path(path);