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 btrfs_init_path(&path);
29 key.objectid = blocknr;
31 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
32 key.offset = num_blocks;
33 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
38 l = btrfs_buffer_leaf(path.nodes[0]);
39 item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
40 refs = btrfs_extent_refs(item);
41 btrfs_set_extent_refs(item, refs + 1);
42 mark_buffer_dirty(path.nodes[0]);
44 btrfs_release_path(root->fs_info->extent_root, &path);
45 finish_current_insert(trans, root->fs_info->extent_root);
46 del_pending_extents(trans, root->fs_info->extent_root);
50 static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
51 *root, u64 blocknr, u64 num_blocks, u32 *refs)
53 struct btrfs_path path;
57 struct btrfs_extent_item *item;
58 btrfs_init_path(&path);
59 key.objectid = blocknr;
60 key.offset = num_blocks;
62 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
63 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
67 l = btrfs_buffer_leaf(path.nodes[0]);
68 item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item);
69 *refs = btrfs_extent_refs(item);
70 btrfs_release_path(root->fs_info->extent_root, &path);
74 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
75 struct buffer_head *buf)
78 struct btrfs_node *buf_node;
79 struct btrfs_leaf *buf_leaf;
80 struct btrfs_disk_key *key;
81 struct btrfs_file_extent_item *fi;
88 buf_node = btrfs_buffer_node(buf);
89 leaf = btrfs_is_leaf(buf_node);
90 buf_leaf = btrfs_buffer_leaf(buf);
91 for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
93 key = &buf_leaf->items[i].key;
94 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
96 fi = btrfs_item_ptr(buf_leaf, i,
97 struct btrfs_file_extent_item);
98 ret = inc_block_ref(trans, root,
99 btrfs_file_extent_disk_blocknr(fi),
100 btrfs_file_extent_disk_num_blocks(fi));
103 blocknr = btrfs_node_blockptr(buf_node, i);
104 ret = inc_block_ref(trans, root, blocknr, 1);
111 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
114 unsigned long gang[8];
118 struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
121 ret = find_first_radix_bit(pinned_radix, gang,
127 for (i = 0; i < ret; i++) {
128 clear_radix_bit(pinned_radix, gang[i]);
131 if (root->fs_info->last_insert.objectid > first)
132 root->fs_info->last_insert.objectid = first;
133 root->fs_info->last_insert.offset = 0;
137 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
138 btrfs_root *extent_root)
140 struct btrfs_key ins;
141 struct btrfs_extent_item extent_item;
144 u64 super_blocks_used;
145 struct btrfs_fs_info *info = extent_root->fs_info;
147 btrfs_set_extent_refs(&extent_item, 1);
148 btrfs_set_extent_owner(&extent_item,
149 btrfs_header_parentid(btrfs_buffer_header(extent_root->node)));
152 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
154 for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) {
155 ins.objectid = extent_root->fs_info->current_insert.objectid +
157 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
158 btrfs_set_super_blocks_used(info->disk_super,
159 super_blocks_used + 1);
160 ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
161 sizeof(extent_item));
164 extent_root->fs_info->current_insert.offset = 0;
168 static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
171 struct btrfs_header *header;
172 struct buffer_head *bh;
175 bh = btrfs_find_tree_block(root, blocknr);
176 if (bh && buffer_uptodate(bh)) {
177 header = btrfs_buffer_header(bh);
178 if (btrfs_header_generation(header) ==
179 root->fs_info->running_transaction->transid) {
185 err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
187 err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
194 * remove an extent from the root, returns 0 on success
196 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
197 *root, u64 blocknr, u64 num_blocks, int pin)
199 struct btrfs_path path;
200 struct btrfs_key key;
201 struct btrfs_fs_info *info = root->fs_info;
202 struct btrfs_root *extent_root = info->extent_root;
204 struct btrfs_extent_item *ei;
205 struct btrfs_key ins;
208 key.objectid = blocknr;
210 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
211 key.offset = num_blocks;
213 find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
214 btrfs_init_path(&path);
215 ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1);
217 printk("failed to find %Lu\n", key.objectid);
218 btrfs_print_tree(extent_root, extent_root->node);
219 printk("failed to find %Lu\n", key.objectid);
222 ei = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
223 struct btrfs_extent_item);
224 BUG_ON(ei->refs == 0);
225 refs = btrfs_extent_refs(ei) - 1;
226 btrfs_set_extent_refs(ei, refs);
227 mark_buffer_dirty(path.nodes[0]);
229 u64 super_blocks_used;
232 ret = pin_down_block(root, blocknr, 0);
236 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
237 btrfs_set_super_blocks_used(info->disk_super,
238 super_blocks_used - num_blocks);
239 ret = btrfs_del_item(trans, extent_root, &path);
240 if (extent_root->fs_info->last_insert.objectid > blocknr)
241 extent_root->fs_info->last_insert.objectid = blocknr;
245 btrfs_release_path(extent_root, &path);
246 finish_current_insert(trans, extent_root);
251 * find all the blocks marked as pending in the radix tree and remove
252 * them from the extent map
254 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
255 btrfs_root *extent_root)
260 unsigned long gang[4];
262 struct radix_tree_root *pending_radix;
263 struct radix_tree_root *pinned_radix;
265 pending_radix = &extent_root->fs_info->pending_del_radix;
266 pinned_radix = &extent_root->fs_info->pinned_radix;
269 ret = find_first_radix_bit(pending_radix, gang,
273 for (i = 0; i < ret; i++) {
274 wret = set_radix_bit(pinned_radix, gang[i]);
276 wret = clear_radix_bit(pending_radix, gang[i]);
278 wret = __free_extent(trans, extent_root,
288 * remove an extent from the root, returns 0 on success
290 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
291 *root, u64 blocknr, u64 num_blocks, int pin)
293 struct btrfs_root *extent_root = root->fs_info->extent_root;
297 if (root == extent_root) {
298 pin_down_block(root, blocknr, 1);
301 ret = __free_extent(trans, root, blocknr, num_blocks, pin);
302 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
303 return ret ? ret : pending_ret;
307 * walks the btree of allocated extents and find a hole of a given size.
308 * The key ins is changed to record the hole:
309 * ins->objectid == block start
310 * ins->flags = BTRFS_EXTENT_ITEM_KEY
311 * ins->offset == number of blocks
312 * Any available blocks before search_start are skipped.
314 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
315 *orig_root, u64 num_blocks, u64 search_start, u64
316 search_end, struct btrfs_key *ins)
318 struct btrfs_path path;
319 struct btrfs_key key;
326 struct btrfs_leaf *l;
327 struct btrfs_root * root = orig_root->fs_info->extent_root;
328 int total_needed = num_blocks;
331 level = btrfs_header_level(btrfs_buffer_header(root->node));
332 total_needed += (level + 1) * 3;
333 if (root->fs_info->last_insert.objectid > search_start)
334 search_start = root->fs_info->last_insert.objectid;
337 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
340 btrfs_init_path(&path);
341 ins->objectid = search_start;
344 ret = btrfs_search_slot(trans, root, ins, &path, 0, 0);
348 if (path.slots[0] > 0)
352 l = btrfs_buffer_leaf(path.nodes[0]);
353 slot = path.slots[0];
354 if (slot >= btrfs_header_nritems(&l->header)) {
355 ret = btrfs_next_leaf(root, &path);
361 ins->objectid = search_start;
362 ins->offset = (u64)-1;
366 ins->objectid = last_block > search_start ?
367 last_block : search_start;
368 ins->offset = (u64)-1;
371 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
372 if (key.objectid >= search_start) {
374 if (last_block < search_start)
375 last_block = search_start;
376 hole_size = key.objectid - last_block;
377 if (hole_size > total_needed) {
378 ins->objectid = last_block;
379 ins->offset = hole_size;
385 last_block = key.objectid + key.offset;
390 /* we have to make sure we didn't find an extent that has already
391 * been allocated by the map tree or the original allocation
393 btrfs_release_path(root, &path);
394 BUG_ON(ins->objectid < search_start);
395 for (test_block = ins->objectid;
396 test_block < ins->objectid + total_needed; test_block++) {
397 if (test_radix_bit(&root->fs_info->pinned_radix,
399 search_start = test_block + 1;
403 BUG_ON(root->fs_info->current_insert.offset);
404 root->fs_info->current_insert.offset = total_needed - num_blocks;
405 root->fs_info->current_insert.objectid = ins->objectid + num_blocks;
406 root->fs_info->current_insert.flags = 0;
407 root->fs_info->last_insert.objectid = ins->objectid;
408 ins->offset = num_blocks;
411 btrfs_release_path(root, &path);
416 * finds a free extent and does all the dirty work required for allocation
417 * returns the key for the extent through ins, and a tree buffer for
418 * the first block of the extent through buf.
420 * returns 0 if everything worked, non-zero otherwise.
422 int btrfs_alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
423 *root, u64 num_blocks, u64 search_start, u64
424 search_end, u64 owner, struct btrfs_key *ins)
428 u64 super_blocks_used;
429 struct btrfs_fs_info *info = root->fs_info;
430 struct btrfs_root *extent_root = info->extent_root;
431 struct btrfs_extent_item extent_item;
433 btrfs_set_extent_refs(&extent_item, 1);
434 btrfs_set_extent_owner(&extent_item, owner);
436 if (root == extent_root) {
437 BUG_ON(extent_root->fs_info->current_insert.offset == 0);
438 BUG_ON(num_blocks != 1);
439 BUG_ON(extent_root->fs_info->current_insert.flags ==
440 extent_root->fs_info->current_insert.offset);
442 ins->objectid = extent_root->fs_info->current_insert.objectid +
443 extent_root->fs_info->current_insert.flags++;
446 ret = find_free_extent(trans, root, num_blocks, search_start,
451 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
452 btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
454 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
455 sizeof(extent_item));
457 finish_current_insert(trans, extent_root);
458 pending_ret = del_pending_extents(trans, extent_root);
467 * helper function to allocate a block for a given tree
468 * returns the tree buffer or NULL.
470 struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
471 struct btrfs_root *root)
473 struct btrfs_key ins;
475 struct buffer_head *buf;
477 ret = btrfs_alloc_extent(trans, root, 1, 0, (unsigned long)-1,
478 btrfs_header_parentid(btrfs_buffer_header(root->node)), &ins);
483 buf = btrfs_find_create_tree_block(root, ins.objectid);
484 set_buffer_uptodate(buf);
488 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
489 struct btrfs_root *root, struct buffer_head *cur)
491 struct btrfs_disk_key *key;
492 struct btrfs_leaf *leaf;
493 struct btrfs_file_extent_item *fi;
498 BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
499 leaf = btrfs_buffer_leaf(cur);
500 nritems = btrfs_header_nritems(&leaf->header);
501 for (i = 0; i < nritems; i++) {
502 key = &leaf->items[i].key;
503 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
505 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
507 * FIXME make sure to insert a trans record that
508 * repeats the snapshot del on crash
510 ret = btrfs_free_extent(trans, root,
511 btrfs_file_extent_disk_blocknr(fi),
512 btrfs_file_extent_disk_num_blocks(fi),
520 * helper function for drop_snapshot, this walks down the tree dropping ref
523 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
524 *root, struct btrfs_path *path, int *level)
526 struct buffer_head *next;
527 struct buffer_head *cur;
532 ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
538 * walk down to the last node level and free all the leaves
541 cur = path->nodes[*level];
542 if (path->slots[*level] >=
543 btrfs_header_nritems(btrfs_buffer_header(cur)))
546 ret = drop_leaf_ref(trans, root, cur);
550 blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
551 path->slots[*level]);
552 ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
555 path->slots[*level]++;
556 ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
560 next = read_tree_block(root, blocknr);
561 if (path->nodes[*level-1])
562 btrfs_block_release(root, path->nodes[*level-1]);
563 path->nodes[*level-1] = next;
564 *level = btrfs_header_level(btrfs_buffer_header(next));
565 path->slots[*level] = 0;
568 ret = btrfs_free_extent(trans, root,
569 path->nodes[*level]->b_blocknr, 1, 1);
570 btrfs_block_release(root, path->nodes[*level]);
571 path->nodes[*level] = NULL;
578 * helper for dropping snapshots. This walks back up the tree in the path
579 * to find the first node higher up where we haven't yet gone through
582 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
583 *root, struct btrfs_path *path, int *level)
588 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
589 slot = path->slots[i];
590 if (slot < btrfs_header_nritems(
591 btrfs_buffer_header(path->nodes[i])) - 1) {
596 ret = btrfs_free_extent(trans, root,
597 path->nodes[*level]->b_blocknr,
600 btrfs_block_release(root, path->nodes[*level]);
601 path->nodes[*level] = NULL;
609 * drop the reference count on the tree rooted at 'snap'. This traverses
610 * the tree freeing any blocks that have a ref count of zero after being
613 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
614 *root, struct buffer_head *snap)
619 struct btrfs_path path;
623 btrfs_init_path(&path);
625 level = btrfs_header_level(btrfs_buffer_header(snap));
627 path.nodes[level] = snap;
628 path.slots[level] = 0;
630 wret = walk_down_tree(trans, root, &path, &level);
636 wret = walk_up_tree(trans, root, &path, &level);
642 for (i = 0; i <= orig_level; i++) {
644 btrfs_block_release(root, path.nodes[i]);