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 static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
16 *root, u64 blocknr, u64 num_blocks)
18 struct btrfs_path *path;
22 struct btrfs_extent_item *item;
26 find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1,
28 path = btrfs_alloc_path();
30 btrfs_init_path(path);
31 key.objectid = blocknr;
33 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
34 key.offset = num_blocks;
35 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
40 l = btrfs_buffer_leaf(path->nodes[0]);
41 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
42 refs = btrfs_extent_refs(item);
43 btrfs_set_extent_refs(item, refs + 1);
44 btrfs_mark_buffer_dirty(path->nodes[0]);
46 btrfs_release_path(root->fs_info->extent_root, path);
47 btrfs_free_path(path);
48 finish_current_insert(trans, root->fs_info->extent_root);
49 del_pending_extents(trans, root->fs_info->extent_root);
53 static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
54 *root, u64 blocknr, u64 num_blocks, u32 *refs)
56 struct btrfs_path *path;
60 struct btrfs_extent_item *item;
62 path = btrfs_alloc_path();
63 btrfs_init_path(path);
64 key.objectid = blocknr;
65 key.offset = num_blocks;
67 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
68 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
72 l = btrfs_buffer_leaf(path->nodes[0]);
73 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
74 *refs = btrfs_extent_refs(item);
75 btrfs_release_path(root->fs_info->extent_root, path);
76 btrfs_free_path(path);
80 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
81 struct btrfs_root *root)
83 return inc_block_ref(trans, root, bh_blocknr(root->node), 1);
86 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
87 struct buffer_head *buf)
90 struct btrfs_node *buf_node;
91 struct btrfs_leaf *buf_leaf;
92 struct btrfs_disk_key *key;
93 struct btrfs_file_extent_item *fi;
100 buf_node = btrfs_buffer_node(buf);
101 leaf = btrfs_is_leaf(buf_node);
102 buf_leaf = btrfs_buffer_leaf(buf);
103 for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
105 key = &buf_leaf->items[i].key;
106 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
108 fi = btrfs_item_ptr(buf_leaf, i,
109 struct btrfs_file_extent_item);
110 ret = inc_block_ref(trans, root,
111 btrfs_file_extent_disk_blocknr(fi),
112 btrfs_file_extent_disk_num_blocks(fi));
115 blocknr = btrfs_node_blockptr(buf_node, i);
116 ret = inc_block_ref(trans, root, blocknr, 1);
123 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
126 unsigned long gang[8];
130 struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
133 ret = find_first_radix_bit(pinned_radix, gang,
139 for (i = 0; i < ret; i++) {
140 clear_radix_bit(pinned_radix, gang[i]);
143 if (root->fs_info->last_insert.objectid > first)
144 root->fs_info->last_insert.objectid = first;
145 root->fs_info->last_insert.offset = 0;
149 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
150 btrfs_root *extent_root)
152 struct btrfs_key ins;
153 struct btrfs_extent_item extent_item;
156 u64 super_blocks_used;
157 struct btrfs_fs_info *info = extent_root->fs_info;
159 btrfs_set_extent_refs(&extent_item, 1);
162 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
164 for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) {
165 ins.objectid = extent_root->fs_info->current_insert.objectid +
167 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
168 btrfs_set_super_blocks_used(info->disk_super,
169 super_blocks_used + 1);
170 ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
171 sizeof(extent_item));
174 extent_root->fs_info->current_insert.offset = 0;
178 static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
181 struct btrfs_header *header;
182 struct buffer_head *bh;
185 bh = btrfs_find_tree_block(root, blocknr);
187 if (buffer_uptodate(bh)) {
189 root->fs_info->running_transaction->transid;
190 header = btrfs_buffer_header(bh);
191 if (btrfs_header_generation(header) ==
193 btrfs_block_release(root, bh);
197 btrfs_block_release(root, bh);
199 err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
201 err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
208 * remove an extent from the root, returns 0 on success
210 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
211 *root, u64 blocknr, u64 num_blocks, int pin)
213 struct btrfs_path *path;
214 struct btrfs_key key;
215 struct btrfs_fs_info *info = root->fs_info;
216 struct btrfs_root *extent_root = info->extent_root;
218 struct btrfs_extent_item *ei;
219 struct btrfs_key ins;
222 key.objectid = blocknr;
224 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
225 key.offset = num_blocks;
227 find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
228 path = btrfs_alloc_path();
230 btrfs_init_path(path);
232 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
234 printk("failed to find %Lu\n", key.objectid);
235 btrfs_print_tree(extent_root, extent_root->node);
236 printk("failed to find %Lu\n", key.objectid);
239 ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
240 struct btrfs_extent_item);
241 BUG_ON(ei->refs == 0);
242 refs = btrfs_extent_refs(ei) - 1;
243 btrfs_set_extent_refs(ei, refs);
244 btrfs_mark_buffer_dirty(path->nodes[0]);
246 u64 super_blocks_used;
249 ret = pin_down_block(root, blocknr, 0);
253 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
254 btrfs_set_super_blocks_used(info->disk_super,
255 super_blocks_used - num_blocks);
256 ret = btrfs_del_item(trans, extent_root, path);
260 btrfs_release_path(extent_root, path);
261 btrfs_free_path(path);
262 finish_current_insert(trans, extent_root);
267 * find all the blocks marked as pending in the radix tree and remove
268 * them from the extent map
270 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
271 btrfs_root *extent_root)
276 unsigned long gang[4];
278 struct radix_tree_root *pending_radix;
279 struct radix_tree_root *pinned_radix;
281 pending_radix = &extent_root->fs_info->pending_del_radix;
282 pinned_radix = &extent_root->fs_info->pinned_radix;
285 ret = find_first_radix_bit(pending_radix, gang,
289 for (i = 0; i < ret; i++) {
290 wret = set_radix_bit(pinned_radix, gang[i]);
292 wret = clear_radix_bit(pending_radix, gang[i]);
294 wret = __free_extent(trans, extent_root,
304 * remove an extent from the root, returns 0 on success
306 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
307 *root, u64 blocknr, u64 num_blocks, int pin)
309 struct btrfs_root *extent_root = root->fs_info->extent_root;
313 if (root == extent_root) {
314 pin_down_block(root, blocknr, 1);
317 ret = __free_extent(trans, root, blocknr, num_blocks, pin);
318 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
319 return ret ? ret : pending_ret;
323 * walks the btree of allocated extents and find a hole of a given size.
324 * The key ins is changed to record the hole:
325 * ins->objectid == block start
326 * ins->flags = BTRFS_EXTENT_ITEM_KEY
327 * ins->offset == number of blocks
328 * Any available blocks before search_start are skipped.
330 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
331 *orig_root, u64 num_blocks, u64 search_start, u64
332 search_end, struct btrfs_key *ins)
334 struct btrfs_path *path;
335 struct btrfs_key key;
342 struct btrfs_leaf *l;
343 struct btrfs_root * root = orig_root->fs_info->extent_root;
344 int total_needed = num_blocks;
347 path = btrfs_alloc_path();
349 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
351 level = btrfs_header_level(btrfs_buffer_header(root->node));
352 total_needed += (level + 1) * 3;
353 if (root->fs_info->last_insert.objectid == 0 && search_end == (u64)-1) {
354 struct btrfs_disk_key *last_key;
355 btrfs_init_path(path);
356 ins->objectid = (u64)-1;
357 ins->offset = (u64)-1;
358 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
362 if (path->slots[0] > 0)
364 l = btrfs_buffer_leaf(path->nodes[0]);
365 last_key = &l->items[path->slots[0]].key;
366 search_start = btrfs_disk_key_objectid(last_key);
368 if (root->fs_info->last_insert.objectid > search_start)
369 search_start = root->fs_info->last_insert.objectid;
372 btrfs_init_path(path);
373 ins->objectid = search_start;
376 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
380 if (path->slots[0] > 0)
384 l = btrfs_buffer_leaf(path->nodes[0]);
385 slot = path->slots[0];
386 if (slot >= btrfs_header_nritems(&l->header)) {
387 ret = btrfs_next_leaf(root, path);
393 ins->objectid = search_start;
394 ins->offset = (u64)-1;
398 ins->objectid = last_block > search_start ?
399 last_block : search_start;
400 ins->offset = (u64)-1;
403 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
404 if (key.objectid >= search_start) {
406 if (last_block < search_start)
407 last_block = search_start;
408 hole_size = key.objectid - last_block;
409 if (hole_size > total_needed) {
410 ins->objectid = last_block;
411 ins->offset = hole_size;
417 last_block = key.objectid + key.offset;
422 /* we have to make sure we didn't find an extent that has already
423 * been allocated by the map tree or the original allocation
425 btrfs_release_path(root, path);
426 BUG_ON(ins->objectid < search_start);
427 for (test_block = ins->objectid;
428 test_block < ins->objectid + total_needed; test_block++) {
429 if (test_radix_bit(&root->fs_info->pinned_radix,
431 search_start = test_block + 1;
435 BUG_ON(root->fs_info->current_insert.offset);
436 root->fs_info->current_insert.offset = total_needed - num_blocks;
437 root->fs_info->current_insert.objectid = ins->objectid + num_blocks;
438 root->fs_info->current_insert.flags = 0;
439 root->fs_info->last_insert.objectid = ins->objectid;
440 ins->offset = num_blocks;
441 btrfs_free_path(path);
444 btrfs_release_path(root, path);
445 btrfs_free_path(path);
450 * finds a free extent and does all the dirty work required for allocation
451 * returns the key for the extent through ins, and a tree buffer for
452 * the first block of the extent through buf.
454 * returns 0 if everything worked, non-zero otherwise.
456 int btrfs_alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
457 *root, u64 num_blocks, u64 search_start, u64
458 search_end, struct btrfs_key *ins)
462 u64 super_blocks_used;
463 struct btrfs_fs_info *info = root->fs_info;
464 struct btrfs_root *extent_root = info->extent_root;
465 struct btrfs_extent_item extent_item;
467 btrfs_set_extent_refs(&extent_item, 1);
469 if (root == extent_root) {
470 BUG_ON(extent_root->fs_info->current_insert.offset == 0);
471 BUG_ON(num_blocks != 1);
472 BUG_ON(extent_root->fs_info->current_insert.flags ==
473 extent_root->fs_info->current_insert.offset);
475 ins->objectid = extent_root->fs_info->current_insert.objectid +
476 extent_root->fs_info->current_insert.flags++;
479 ret = find_free_extent(trans, root, num_blocks, search_start,
484 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
485 btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
487 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
488 sizeof(extent_item));
490 finish_current_insert(trans, extent_root);
491 pending_ret = del_pending_extents(trans, extent_root);
500 * helper function to allocate a block for a given tree
501 * returns the tree buffer or NULL.
503 struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
504 struct btrfs_root *root)
506 struct btrfs_key ins;
508 struct buffer_head *buf;
510 ret = btrfs_alloc_extent(trans, root, 1, 0, (unsigned long)-1, &ins);
515 buf = btrfs_find_create_tree_block(root, ins.objectid);
516 set_buffer_uptodate(buf);
520 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
521 struct btrfs_root *root, struct buffer_head *cur)
523 struct btrfs_disk_key *key;
524 struct btrfs_leaf *leaf;
525 struct btrfs_file_extent_item *fi;
530 BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
531 leaf = btrfs_buffer_leaf(cur);
532 nritems = btrfs_header_nritems(&leaf->header);
533 for (i = 0; i < nritems; i++) {
534 key = &leaf->items[i].key;
535 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
537 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
539 * FIXME make sure to insert a trans record that
540 * repeats the snapshot del on crash
542 ret = btrfs_free_extent(trans, root,
543 btrfs_file_extent_disk_blocknr(fi),
544 btrfs_file_extent_disk_num_blocks(fi),
552 * helper function for drop_snapshot, this walks down the tree dropping ref
555 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
556 *root, struct btrfs_path *path, int *level)
558 struct buffer_head *next;
559 struct buffer_head *cur;
565 WARN_ON(*level >= BTRFS_MAX_LEVEL);
566 ret = lookup_block_ref(trans, root, bh_blocknr(path->nodes[*level]),
572 * walk down to the last node level and free all the leaves
576 WARN_ON(*level >= BTRFS_MAX_LEVEL);
577 cur = path->nodes[*level];
578 if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
580 if (path->slots[*level] >=
581 btrfs_header_nritems(btrfs_buffer_header(cur)))
584 ret = drop_leaf_ref(trans, root, cur);
588 blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
589 path->slots[*level]);
590 ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
593 path->slots[*level]++;
594 ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
598 next = read_tree_block(root, blocknr);
599 WARN_ON(*level <= 0);
600 if (path->nodes[*level-1])
601 btrfs_block_release(root, path->nodes[*level-1]);
602 path->nodes[*level-1] = next;
603 *level = btrfs_header_level(btrfs_buffer_header(next));
604 path->slots[*level] = 0;
608 WARN_ON(*level >= BTRFS_MAX_LEVEL);
609 ret = btrfs_free_extent(trans, root,
610 bh_blocknr(path->nodes[*level]), 1, 1);
611 btrfs_block_release(root, path->nodes[*level]);
612 path->nodes[*level] = NULL;
619 * helper for dropping snapshots. This walks back up the tree in the path
620 * to find the first node higher up where we haven't yet gone through
623 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
624 *root, struct btrfs_path *path, int *level)
629 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
630 slot = path->slots[i];
631 if (slot < btrfs_header_nritems(
632 btrfs_buffer_header(path->nodes[i])) - 1) {
637 ret = btrfs_free_extent(trans, root,
638 bh_blocknr(path->nodes[*level]),
641 btrfs_block_release(root, path->nodes[*level]);
642 path->nodes[*level] = NULL;
650 * drop the reference count on the tree rooted at 'snap'. This traverses
651 * the tree freeing any blocks that have a ref count of zero after being
654 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
655 *root, struct buffer_head *snap)
660 struct btrfs_path *path;
664 path = btrfs_alloc_path();
666 btrfs_init_path(path);
668 level = btrfs_header_level(btrfs_buffer_header(snap));
670 path->nodes[level] = snap;
671 path->slots[level] = 0;
673 wret = walk_down_tree(trans, root, path, &level);
679 wret = walk_up_tree(trans, root, path, &level);
685 for (i = 0; i <= orig_level; i++) {
686 if (path->nodes[i]) {
687 btrfs_block_release(root, path->nodes[i]);
690 btrfs_free_path(path);