3 #include "kerncompat.h"
4 #include "radix-tree.h"
7 #include "print-tree.h"
10 * pending extents are blocks that we're trying to allocate in the extent
11 * map while trying to grow the map because of other allocations. To avoid
12 * recursing, they are tagged in the radix tree and cleaned up after
13 * other allocations are done. The pending tag is also used in the same
16 #define CTREE_EXTENT_PENDING 0
18 static int inc_block_ref(struct ctree_root *root, u64 blocknr)
20 struct ctree_path path;
24 struct extent_item *item;
26 key.objectid = blocknr;
29 ret = search_slot(root->extent_root, &key, &path, 0, 1);
31 l = &path.nodes[0]->leaf;
32 item = (struct extent_item *)(l->data +
33 l->items[path.slots[0]].offset);
35 BUG_ON(list_empty(&path.nodes[0]->dirty));
36 release_path(root->extent_root, &path);
40 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
44 for (i = 0; i < buf->node.header.nritems; i++) {
45 blocknr = buf->node.blockptrs[i];
46 inc_block_ref(root, blocknr);
52 * find all the blocks marked as pending in the radix tree and remove
53 * them from the extent map
55 static int del_pending_extents(struct ctree_root *extent_root)
59 struct tree_buffer *gang[4];
61 struct ctree_path path;
64 ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
67 CTREE_EXTENT_PENDING);
70 for (i = 0; i < ret; i++) {
71 key.objectid = gang[i]->blocknr;
75 ret = search_slot(extent_root, &key, &path, -1, 1);
77 print_tree(extent_root, extent_root->node);
78 printf("unable to find %Lu\n", key.objectid);
80 // FIXME undo it and return sane
83 ret = del_item(extent_root, &path);
88 release_path(extent_root, &path);
89 radix_tree_tag_clear(&extent_root->cache_radix,
91 CTREE_EXTENT_PENDING);
92 tree_block_release(extent_root, gang[i]);
99 * remove an extent from the root, returns 0 on success
101 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
103 struct ctree_path path;
105 struct ctree_root *extent_root = root->extent_root;
106 struct tree_buffer *t;
109 key.objectid = blocknr;
111 key.offset = num_blocks;
112 if (root == extent_root) {
113 t = read_tree_block(root, key.objectid);
114 radix_tree_tag_set(&root->cache_radix, key.objectid,
115 CTREE_EXTENT_PENDING);
119 ret = search_slot(extent_root, &key, &path, -1, 1);
121 print_tree(extent_root, extent_root->node);
122 printf("failed to find %Lu\n", key.objectid);
125 ret = del_item(extent_root, &path);
128 release_path(extent_root, &path);
129 pending_ret = del_pending_extents(root->extent_root);
130 return ret ? ret : pending_ret;
134 * walks the btree of allocated extents and find a hole of a given size.
135 * The key ins is changed to record the hole:
136 * ins->objectid == block start
138 * ins->offset == number of blocks
139 * Any available blocks before search_start are skipped.
141 static int find_free_extent(struct ctree_root *orig_root, u64 num_blocks,
142 u64 search_start, u64 search_end, struct key *ins)
144 struct ctree_path path;
152 struct ctree_root * root = orig_root->extent_root;
156 ins->objectid = search_start;
160 ret = search_slot(root, ins, &path, 0, 0);
165 l = &path.nodes[0]->leaf;
166 slot = path.slots[0];
167 if (slot >= l->header.nritems) {
168 ret = next_leaf(root, &path);
174 ins->objectid = search_start;
175 ins->offset = num_blocks;
179 ins->objectid = last_block > search_start ?
180 last_block : search_start;
181 ins->offset = num_blocks;
184 key = &l->items[slot].key;
185 if (key->objectid >= search_start) {
187 hole_size = key->objectid - last_block;
188 if (hole_size > num_blocks) {
189 ins->objectid = last_block;
190 ins->offset = num_blocks;
195 last_block = key->objectid + key->offset;
201 /* we have to make sure we didn't find an extent that has already
202 * been allocated by the map tree or the original allocation
204 release_path(root, &path);
205 BUG_ON(ins->objectid < search_start);
206 if (orig_root->extent_root == orig_root) {
207 BUG_ON(num_blocks != 1);
208 if ((root->current_insert.objectid <= ins->objectid &&
209 root->current_insert.objectid +
210 root->current_insert.offset > ins->objectid) ||
211 (root->current_insert.objectid > ins->objectid &&
212 root->current_insert.objectid <= ins->objectid +
214 radix_tree_tag_get(&root->cache_radix, ins->objectid,
215 CTREE_EXTENT_PENDING)) {
216 search_start = ins->objectid + 1;
220 if (ins->offset != 1)
224 release_path(root, &path);
229 * insert all of the pending extents reserved during the original
230 * allocation. (CTREE_EXTENT_PENDING). Returns zero if it all worked out
232 static int insert_pending_extents(struct ctree_root *extent_root)
236 struct extent_item item;
237 struct tree_buffer *gang[4];
242 item.owner = extent_root->node->node.header.parentid;
244 ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
247 CTREE_EXTENT_PENDING);
250 for (i = 0; i < ret; i++) {
251 key.objectid = gang[i]->blocknr;
254 ret = insert_item(extent_root, &key, &item,
257 printf("%Lu already in tree\n", key.objectid);
258 print_tree(extent_root, extent_root->node);
260 // FIXME undo it and return sane
263 radix_tree_tag_clear(&extent_root->cache_radix,
265 CTREE_EXTENT_PENDING);
266 printf("%Lu is not pending\n", gang[i]->blocknr);
267 tree_block_release(extent_root, gang[i]);
274 * finds a free extent and does all the dirty work required for allocation
275 * returns the key for the extent through ins, and a tree buffer for
276 * the first block of the extent through buf.
278 * returns 0 if everything worked, non-zero otherwise.
280 int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
281 u64 search_end, u64 owner, struct key *ins,
282 struct tree_buffer **buf)
286 struct extent_item extent_item;
287 extent_item.refs = 1;
288 extent_item.owner = owner;
290 ret = find_free_extent(root, num_blocks, search_start, search_end, ins);
293 if (root != root->extent_root) {
294 memcpy(&root->extent_root->current_insert, ins, sizeof(*ins));
295 ret = insert_item(root->extent_root, ins, &extent_item,
296 sizeof(extent_item));
297 memset(&root->extent_root->current_insert, 0,
299 pending_ret = insert_pending_extents(root->extent_root);
304 *buf = find_tree_block(root, ins->objectid);
305 dirty_tree_block(root, *buf);
308 /* we're allocating an extent for the extent tree, don't recurse */
309 BUG_ON(ins->offset != 1);
310 *buf = find_tree_block(root, ins->objectid);
312 printf("%Lu is pending\n", ins->objectid);
313 radix_tree_tag_set(&root->cache_radix, ins->objectid,
314 CTREE_EXTENT_PENDING);
316 dirty_tree_block(root, *buf);
322 * helper function to allocate a block for a given tree
323 * returns the tree buffer or NULL.
325 struct tree_buffer *alloc_free_block(struct ctree_root *root)
329 struct tree_buffer *buf = NULL;
331 ret = alloc_extent(root, 1, 0, (unsigned long)-1,
332 root->node->node.header.parentid,
339 if (root != root->extent_root)
340 BUG_ON(radix_tree_tag_get(&root->extent_root->cache_radix,
341 buf->blocknr, CTREE_EXTENT_PENDING));