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
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);
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, u32 *refs)
53 struct btrfs_path path;
57 struct btrfs_extent_item *item;
58 btrfs_init_path(&path);
59 key.objectid = blocknr;
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;
83 buf_node = btrfs_buffer_node(buf);
84 if (btrfs_is_leaf(buf_node))
87 for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
88 blocknr = btrfs_node_blockptr(buf_node, i);
89 inc_block_ref(trans, root, blocknr);
94 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
97 unsigned long gang[8];
101 struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
104 ret = find_first_radix_bit(pinned_radix, gang,
110 for (i = 0; i < ret; i++) {
111 clear_radix_bit(pinned_radix, gang[i]);
114 if (root->fs_info->last_insert.objectid > first)
115 root->fs_info->last_insert.objectid = first;
116 root->fs_info->last_insert.offset = 0;
120 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
121 btrfs_root *extent_root)
123 struct btrfs_key ins;
124 struct btrfs_extent_item extent_item;
127 u64 super_blocks_used;
128 struct btrfs_fs_info *info = extent_root->fs_info;
130 btrfs_set_extent_refs(&extent_item, 1);
131 btrfs_set_extent_owner(&extent_item,
132 btrfs_header_parentid(btrfs_buffer_header(extent_root->node)));
135 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
137 for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) {
138 ins.objectid = extent_root->fs_info->current_insert.objectid +
140 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
141 btrfs_set_super_blocks_used(info->disk_super,
142 super_blocks_used + 1);
143 ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
144 sizeof(extent_item));
147 extent_root->fs_info->current_insert.offset = 0;
151 static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
154 struct btrfs_header *header;
155 struct buffer_head *bh;
157 bh = sb_find_get_block(root->fs_info->sb, blocknr);
159 header = btrfs_buffer_header(bh);
160 if (btrfs_header_generation(header) ==
161 root->fs_info->running_transaction->transid) {
168 err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
170 err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
176 * remove an extent from the root, returns 0 on success
178 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
179 *root, u64 blocknr, u64 num_blocks, int pin)
181 struct btrfs_path path;
182 struct btrfs_key key;
183 struct btrfs_fs_info *info = root->fs_info;
184 struct btrfs_root *extent_root = info->extent_root;
186 struct btrfs_extent_item *ei;
187 struct btrfs_key ins;
190 key.objectid = blocknr;
192 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
193 key.offset = num_blocks;
195 find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
196 btrfs_init_path(&path);
197 ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1);
199 printk("failed to find %Lu\n", key.objectid);
200 btrfs_print_tree(extent_root, extent_root->node);
201 printk("failed to find %Lu\n", key.objectid);
204 ei = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
205 struct btrfs_extent_item);
206 BUG_ON(ei->refs == 0);
207 refs = btrfs_extent_refs(ei) - 1;
208 btrfs_set_extent_refs(ei, refs);
210 u64 super_blocks_used;
213 ret = pin_down_block(root, blocknr, 0);
217 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
218 btrfs_set_super_blocks_used(info->disk_super,
219 super_blocks_used - num_blocks);
220 ret = btrfs_del_item(trans, extent_root, &path);
221 if (extent_root->fs_info->last_insert.objectid > blocknr)
222 extent_root->fs_info->last_insert.objectid = blocknr;
226 mark_buffer_dirty(path.nodes[0]);
227 btrfs_release_path(extent_root, &path);
228 finish_current_insert(trans, extent_root);
233 * find all the blocks marked as pending in the radix tree and remove
234 * them from the extent map
236 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
237 btrfs_root *extent_root)
242 unsigned long gang[4];
244 struct radix_tree_root *pending_radix;
245 struct radix_tree_root *pinned_radix;
247 pending_radix = &extent_root->fs_info->pending_del_radix;
248 pinned_radix = &extent_root->fs_info->pinned_radix;
251 ret = find_first_radix_bit(pending_radix, gang,
255 for (i = 0; i < ret; i++) {
256 wret = set_radix_bit(pinned_radix, gang[i]);
258 wret = clear_radix_bit(pending_radix, gang[i]);
260 wret = __free_extent(trans, extent_root,
270 * remove an extent from the root, returns 0 on success
272 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
273 *root, u64 blocknr, u64 num_blocks, int pin)
275 struct btrfs_root *extent_root = root->fs_info->extent_root;
276 struct buffer_head *t;
280 if (root == extent_root) {
281 t = find_tree_block(root, blocknr);
282 pin_down_block(root, blocknr, 1);
285 ret = __free_extent(trans, root, blocknr, num_blocks, pin);
286 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
287 return ret ? ret : pending_ret;
291 * walks the btree of allocated extents and find a hole of a given size.
292 * The key ins is changed to record the hole:
293 * ins->objectid == block start
294 * ins->flags = BTRFS_EXTENT_ITEM_KEY
295 * ins->offset == number of blocks
296 * Any available blocks before search_start are skipped.
298 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
299 *orig_root, u64 num_blocks, u64 search_start, u64
300 search_end, struct btrfs_key *ins)
302 struct btrfs_path path;
303 struct btrfs_key key;
310 struct btrfs_leaf *l;
311 struct btrfs_root * root = orig_root->fs_info->extent_root;
312 int total_needed = num_blocks;
315 level = btrfs_header_level(btrfs_buffer_header(root->node));
316 total_needed += (level + 1) * 3;
317 if (root->fs_info->last_insert.objectid > search_start)
318 search_start = root->fs_info->last_insert.objectid;
321 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
324 btrfs_init_path(&path);
325 ins->objectid = search_start;
328 ret = btrfs_search_slot(trans, root, ins, &path, 0, 0);
332 if (path.slots[0] > 0)
336 l = btrfs_buffer_leaf(path.nodes[0]);
337 slot = path.slots[0];
338 if (slot >= btrfs_header_nritems(&l->header)) {
339 ret = btrfs_next_leaf(root, &path);
345 ins->objectid = search_start;
346 ins->offset = (u64)-1;
350 ins->objectid = last_block > search_start ?
351 last_block : search_start;
352 ins->offset = (u64)-1;
355 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
356 if (key.objectid >= search_start) {
358 if (last_block < search_start)
359 last_block = search_start;
360 hole_size = key.objectid - last_block;
361 if (hole_size > total_needed) {
362 ins->objectid = last_block;
363 ins->offset = hole_size;
369 last_block = key.objectid + key.offset;
374 /* we have to make sure we didn't find an extent that has already
375 * been allocated by the map tree or the original allocation
377 btrfs_release_path(root, &path);
378 BUG_ON(ins->objectid < search_start);
379 for (test_block = ins->objectid;
380 test_block < ins->objectid + total_needed; test_block++) {
381 if (test_radix_bit(&root->fs_info->pinned_radix,
383 search_start = test_block + 1;
387 BUG_ON(root->fs_info->current_insert.offset);
388 root->fs_info->current_insert.offset = total_needed - num_blocks;
389 root->fs_info->current_insert.objectid = ins->objectid + num_blocks;
390 root->fs_info->current_insert.flags = 0;
391 root->fs_info->last_insert.objectid = ins->objectid;
392 ins->offset = num_blocks;
395 btrfs_release_path(root, &path);
400 * finds a free extent and does all the dirty work required for allocation
401 * returns the key for the extent through ins, and a tree buffer for
402 * the first block of the extent through buf.
404 * returns 0 if everything worked, non-zero otherwise.
406 static int alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
407 *root, u64 num_blocks, u64 search_start, u64
408 search_end, u64 owner, struct btrfs_key *ins)
412 u64 super_blocks_used;
413 struct btrfs_fs_info *info = root->fs_info;
414 struct btrfs_root *extent_root = info->extent_root;
415 struct btrfs_extent_item extent_item;
417 btrfs_set_extent_refs(&extent_item, 1);
418 btrfs_set_extent_owner(&extent_item, owner);
420 if (root == extent_root) {
421 BUG_ON(extent_root->fs_info->current_insert.offset == 0);
422 BUG_ON(num_blocks != 1);
423 BUG_ON(extent_root->fs_info->current_insert.flags ==
424 extent_root->fs_info->current_insert.offset);
426 ins->objectid = extent_root->fs_info->current_insert.objectid +
427 extent_root->fs_info->current_insert.flags++;
430 ret = find_free_extent(trans, root, num_blocks, search_start,
435 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
436 btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
438 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
439 sizeof(extent_item));
441 finish_current_insert(trans, extent_root);
442 pending_ret = del_pending_extents(trans, extent_root);
451 * helper function to allocate a block for a given tree
452 * returns the tree buffer or NULL.
454 struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
455 struct btrfs_root *root)
457 struct btrfs_key ins;
459 struct buffer_head *buf;
461 ret = alloc_extent(trans, root, 1, 0, (unsigned long)-1,
462 btrfs_header_parentid(btrfs_buffer_header(root->node)), &ins);
467 buf = find_tree_block(root, ins.objectid);
468 set_buffer_uptodate(buf);
473 * helper function for drop_snapshot, this walks down the tree dropping ref
476 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
477 *root, struct btrfs_path *path, int *level)
479 struct buffer_head *next;
480 struct buffer_head *cur;
485 ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
491 * walk down to the last node level and free all the leaves
494 cur = path->nodes[*level];
495 if (path->slots[*level] >=
496 btrfs_header_nritems(btrfs_buffer_header(cur)))
498 blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
499 path->slots[*level]);
500 ret = lookup_block_ref(trans, root, blocknr, &refs);
501 if (refs != 1 || *level == 1) {
502 path->slots[*level]++;
503 ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
508 next = read_tree_block(root, blocknr);
509 if (path->nodes[*level-1])
510 btrfs_block_release(root, path->nodes[*level-1]);
511 path->nodes[*level-1] = next;
512 *level = btrfs_header_level(btrfs_buffer_header(next));
513 path->slots[*level] = 0;
516 ret = btrfs_free_extent(trans, root, path->nodes[*level]->b_blocknr,
518 btrfs_block_release(root, path->nodes[*level]);
519 path->nodes[*level] = NULL;
526 * helper for dropping snapshots. This walks back up the tree in the path
527 * to find the first node higher up where we haven't yet gone through
530 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
531 *root, struct btrfs_path *path, int *level)
536 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
537 slot = path->slots[i];
538 if (slot < btrfs_header_nritems(
539 btrfs_buffer_header(path->nodes[i])) - 1) {
544 ret = btrfs_free_extent(trans, root,
545 path->nodes[*level]->b_blocknr,
547 btrfs_block_release(root, path->nodes[*level]);
548 path->nodes[*level] = NULL;
557 * drop the reference count on the tree rooted at 'snap'. This traverses
558 * the tree freeing any blocks that have a ref count of zero after being
561 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
562 *root, struct buffer_head *snap)
567 struct btrfs_path path;
571 btrfs_init_path(&path);
573 level = btrfs_header_level(btrfs_buffer_header(snap));
575 path.nodes[level] = snap;
576 path.slots[level] = 0;
578 wret = walk_down_tree(trans, root, &path, &level);
584 wret = walk_up_tree(trans, root, &path, &level);
590 for (i = 0; i <= orig_level; i++) {
592 btrfs_block_release(root, path.nodes[i]);