Commit | Line | Data |
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fec577fb CM |
1 | #include <stdio.h> |
2 | #include <stdlib.h> | |
3 | #include "kerncompat.h" | |
4 | #include "radix-tree.h" | |
5 | #include "ctree.h" | |
6 | #include "disk-io.h" | |
7 | #include "print-tree.h" | |
e089f05c | 8 | #include "transaction.h" |
fec577fb | 9 | |
e089f05c CM |
10 | static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
11 | *orig_root, u64 num_blocks, u64 search_start, u64 | |
12 | search_end, struct btrfs_key *ins); | |
13 | static int finish_current_insert(struct btrfs_trans_handle *trans, struct | |
14 | btrfs_root *extent_root); | |
15 | static int run_pending(struct btrfs_trans_handle *trans, struct btrfs_root | |
16 | *extent_root); | |
037e6390 | 17 | |
fec577fb CM |
18 | /* |
19 | * pending extents are blocks that we're trying to allocate in the extent | |
20 | * map while trying to grow the map because of other allocations. To avoid | |
21 | * recursing, they are tagged in the radix tree and cleaned up after | |
22 | * other allocations are done. The pending tag is also used in the same | |
23 | * manner for deletes. | |
24 | */ | |
037e6390 | 25 | #define CTREE_EXTENT_PENDING_DEL 0 |
fec577fb | 26 | |
e089f05c CM |
27 | static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root |
28 | *root, u64 blocknr) | |
02217ed2 | 29 | { |
234b63a0 | 30 | struct btrfs_path path; |
02217ed2 | 31 | int ret; |
e2fa7227 | 32 | struct btrfs_key key; |
234b63a0 CM |
33 | struct btrfs_leaf *l; |
34 | struct btrfs_extent_item *item; | |
e2fa7227 | 35 | struct btrfs_key ins; |
cf27e1ee | 36 | u32 refs; |
037e6390 | 37 | |
9f5fae2f CM |
38 | find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1, |
39 | &ins); | |
234b63a0 | 40 | btrfs_init_path(&path); |
02217ed2 CM |
41 | key.objectid = blocknr; |
42 | key.flags = 0; | |
62e2749e | 43 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); |
02217ed2 | 44 | key.offset = 1; |
9f5fae2f CM |
45 | ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path, |
46 | 0, 1); | |
a28ec197 CM |
47 | if (ret != 0) |
48 | BUG(); | |
02217ed2 CM |
49 | BUG_ON(ret != 0); |
50 | l = &path.nodes[0]->leaf; | |
4beb1b8b | 51 | item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item); |
cf27e1ee CM |
52 | refs = btrfs_extent_refs(item); |
53 | btrfs_set_extent_refs(item, refs + 1); | |
a28ec197 | 54 | |
02217ed2 | 55 | BUG_ON(list_empty(&path.nodes[0]->dirty)); |
9f5fae2f CM |
56 | btrfs_release_path(root->fs_info->extent_root, &path); |
57 | finish_current_insert(trans, root->fs_info->extent_root); | |
58 | run_pending(trans, root->fs_info->extent_root); | |
02217ed2 CM |
59 | return 0; |
60 | } | |
61 | ||
e089f05c CM |
62 | static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root |
63 | *root, u64 blocknr, u32 *refs) | |
a28ec197 | 64 | { |
234b63a0 | 65 | struct btrfs_path path; |
a28ec197 | 66 | int ret; |
e2fa7227 | 67 | struct btrfs_key key; |
234b63a0 CM |
68 | struct btrfs_leaf *l; |
69 | struct btrfs_extent_item *item; | |
70 | btrfs_init_path(&path); | |
a28ec197 | 71 | key.objectid = blocknr; |
a28ec197 | 72 | key.offset = 1; |
62e2749e CM |
73 | key.flags = 0; |
74 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); | |
9f5fae2f CM |
75 | ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path, |
76 | 0, 0); | |
a28ec197 CM |
77 | if (ret != 0) |
78 | BUG(); | |
79 | l = &path.nodes[0]->leaf; | |
4beb1b8b | 80 | item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item); |
cf27e1ee | 81 | *refs = btrfs_extent_refs(item); |
9f5fae2f | 82 | btrfs_release_path(root->fs_info->extent_root, &path); |
a28ec197 CM |
83 | return 0; |
84 | } | |
85 | ||
e089f05c CM |
86 | int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
87 | struct btrfs_buffer *buf) | |
02217ed2 CM |
88 | { |
89 | u64 blocknr; | |
90 | int i; | |
a28ec197 | 91 | |
3768f368 | 92 | if (!root->ref_cows) |
a28ec197 | 93 | return 0; |
7518a238 | 94 | if (btrfs_is_leaf(&buf->node)) |
a28ec197 CM |
95 | return 0; |
96 | ||
7518a238 | 97 | for (i = 0; i < btrfs_header_nritems(&buf->node.header); i++) { |
1d4f8a0c | 98 | blocknr = btrfs_node_blockptr(&buf->node, i); |
e089f05c | 99 | inc_block_ref(trans, root, blocknr); |
02217ed2 CM |
100 | } |
101 | return 0; | |
102 | } | |
103 | ||
e089f05c CM |
104 | int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct |
105 | btrfs_root *root) | |
a28ec197 | 106 | { |
a28ec197 | 107 | unsigned long gang[8]; |
88fd146c | 108 | u64 first = 0; |
a28ec197 CM |
109 | int ret; |
110 | int i; | |
111 | ||
112 | while(1) { | |
9f5fae2f CM |
113 | ret = radix_tree_gang_lookup(&root->fs_info->pinned_radix, |
114 | (void **)gang, 0, | |
115 | ARRAY_SIZE(gang)); | |
a28ec197 CM |
116 | if (!ret) |
117 | break; | |
88fd146c CM |
118 | if (!first) |
119 | first = gang[0]; | |
0579da42 | 120 | for (i = 0; i < ret; i++) { |
9f5fae2f CM |
121 | radix_tree_delete(&root->fs_info->pinned_radix, |
122 | gang[i]); | |
0579da42 | 123 | } |
a28ec197 | 124 | } |
9f5fae2f CM |
125 | root->fs_info->last_insert.objectid = first; |
126 | root->fs_info->last_insert.offset = 0; | |
a28ec197 CM |
127 | return 0; |
128 | } | |
129 | ||
e089f05c CM |
130 | static int finish_current_insert(struct btrfs_trans_handle *trans, struct |
131 | btrfs_root *extent_root) | |
037e6390 | 132 | { |
e2fa7227 | 133 | struct btrfs_key ins; |
234b63a0 | 134 | struct btrfs_extent_item extent_item; |
037e6390 CM |
135 | int i; |
136 | int ret; | |
137 | ||
cf27e1ee CM |
138 | btrfs_set_extent_refs(&extent_item, 1); |
139 | btrfs_set_extent_owner(&extent_item, | |
140 | btrfs_header_parentid(&extent_root->node->node.header)); | |
037e6390 CM |
141 | ins.offset = 1; |
142 | ins.flags = 0; | |
62e2749e | 143 | btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY); |
037e6390 | 144 | |
9f5fae2f CM |
145 | for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) { |
146 | ins.objectid = extent_root->fs_info->current_insert.objectid + | |
147 | i; | |
e089f05c CM |
148 | ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item, |
149 | sizeof(extent_item)); | |
037e6390 CM |
150 | BUG_ON(ret); |
151 | } | |
9f5fae2f | 152 | extent_root->fs_info->current_insert.offset = 0; |
037e6390 CM |
153 | return 0; |
154 | } | |
155 | ||
fec577fb | 156 | /* |
a28ec197 | 157 | * remove an extent from the root, returns 0 on success |
fec577fb | 158 | */ |
e089f05c CM |
159 | static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
160 | *root, u64 blocknr, u64 num_blocks, int pin) | |
a28ec197 | 161 | { |
234b63a0 | 162 | struct btrfs_path path; |
e2fa7227 | 163 | struct btrfs_key key; |
9f5fae2f | 164 | struct btrfs_root *extent_root = root->fs_info->extent_root; |
a28ec197 | 165 | int ret; |
234b63a0 | 166 | struct btrfs_extent_item *ei; |
e2fa7227 | 167 | struct btrfs_key ins; |
cf27e1ee | 168 | u32 refs; |
037e6390 | 169 | |
88fd146c | 170 | BUG_ON(pin && num_blocks != 1); |
a28ec197 CM |
171 | key.objectid = blocknr; |
172 | key.flags = 0; | |
62e2749e | 173 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); |
a28ec197 CM |
174 | key.offset = num_blocks; |
175 | ||
e089f05c | 176 | find_free_extent(trans, root, 0, 0, (u64)-1, &ins); |
234b63a0 | 177 | btrfs_init_path(&path); |
e089f05c | 178 | ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1); |
a28ec197 CM |
179 | if (ret) { |
180 | printf("failed to find %Lu\n", key.objectid); | |
234b63a0 | 181 | btrfs_print_tree(extent_root, extent_root->node); |
a28ec197 CM |
182 | printf("failed to find %Lu\n", key.objectid); |
183 | BUG(); | |
184 | } | |
123abc88 CM |
185 | ei = btrfs_item_ptr(&path.nodes[0]->leaf, path.slots[0], |
186 | struct btrfs_extent_item); | |
a28ec197 | 187 | BUG_ON(ei->refs == 0); |
cf27e1ee CM |
188 | refs = btrfs_extent_refs(ei) - 1; |
189 | btrfs_set_extent_refs(ei, refs); | |
190 | if (refs == 0) { | |
88fd146c | 191 | if (pin) { |
a28ec197 CM |
192 | int err; |
193 | radix_tree_preload(GFP_KERNEL); | |
9f5fae2f CM |
194 | err = radix_tree_insert( |
195 | &extent_root->fs_info->pinned_radix, | |
196 | blocknr, (void *)blocknr); | |
a28ec197 CM |
197 | BUG_ON(err); |
198 | radix_tree_preload_end(); | |
199 | } | |
e089f05c | 200 | ret = btrfs_del_item(trans, extent_root, &path); |
9f5fae2f CM |
201 | if (!pin && extent_root->fs_info->last_insert.objectid > |
202 | blocknr) | |
203 | extent_root->fs_info->last_insert.objectid = blocknr; | |
a28ec197 CM |
204 | if (ret) |
205 | BUG(); | |
206 | } | |
234b63a0 | 207 | btrfs_release_path(extent_root, &path); |
e089f05c | 208 | finish_current_insert(trans, extent_root); |
a28ec197 CM |
209 | return ret; |
210 | } | |
211 | ||
a28ec197 CM |
212 | /* |
213 | * find all the blocks marked as pending in the radix tree and remove | |
214 | * them from the extent map | |
215 | */ | |
e089f05c CM |
216 | static int del_pending_extents(struct btrfs_trans_handle *trans, struct |
217 | btrfs_root *extent_root) | |
a28ec197 CM |
218 | { |
219 | int ret; | |
234b63a0 | 220 | struct btrfs_buffer *gang[4]; |
a28ec197 CM |
221 | int i; |
222 | ||
223 | while(1) { | |
9f5fae2f CM |
224 | ret = radix_tree_gang_lookup_tag( |
225 | &extent_root->fs_info->cache_radix, | |
226 | (void **)gang, 0, | |
227 | ARRAY_SIZE(gang), | |
228 | CTREE_EXTENT_PENDING_DEL); | |
a28ec197 CM |
229 | if (!ret) |
230 | break; | |
231 | for (i = 0; i < ret; i++) { | |
e089f05c | 232 | ret = __free_extent(trans, extent_root, |
88fd146c | 233 | gang[i]->blocknr, 1, 1); |
9f5fae2f CM |
234 | radix_tree_tag_clear(&extent_root->fs_info->cache_radix, |
235 | gang[i]->blocknr, | |
236 | CTREE_EXTENT_PENDING_DEL); | |
234b63a0 | 237 | btrfs_block_release(extent_root, gang[i]); |
fec577fb CM |
238 | } |
239 | } | |
240 | return 0; | |
241 | } | |
242 | ||
e089f05c CM |
243 | static int run_pending(struct btrfs_trans_handle *trans, struct btrfs_root |
244 | *extent_root) | |
a28ec197 | 245 | { |
9f5fae2f CM |
246 | while(radix_tree_tagged(&extent_root->fs_info->cache_radix, |
247 | CTREE_EXTENT_PENDING_DEL)) | |
e089f05c | 248 | del_pending_extents(trans, extent_root); |
a28ec197 CM |
249 | return 0; |
250 | } | |
251 | ||
252 | ||
fec577fb CM |
253 | /* |
254 | * remove an extent from the root, returns 0 on success | |
255 | */ | |
e089f05c CM |
256 | int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
257 | *root, u64 blocknr, u64 num_blocks, int pin) | |
fec577fb | 258 | { |
9f5fae2f | 259 | struct btrfs_root *extent_root = root->fs_info->extent_root; |
234b63a0 | 260 | struct btrfs_buffer *t; |
fec577fb CM |
261 | int pending_ret; |
262 | int ret; | |
a28ec197 | 263 | |
fec577fb | 264 | if (root == extent_root) { |
a28ec197 | 265 | t = find_tree_block(root, blocknr); |
9f5fae2f | 266 | radix_tree_tag_set(&root->fs_info->cache_radix, blocknr, |
a28ec197 | 267 | CTREE_EXTENT_PENDING_DEL); |
fec577fb CM |
268 | return 0; |
269 | } | |
e089f05c | 270 | ret = __free_extent(trans, root, blocknr, num_blocks, pin); |
9f5fae2f | 271 | pending_ret = run_pending(trans, root->fs_info->extent_root); |
fec577fb CM |
272 | return ret ? ret : pending_ret; |
273 | } | |
274 | ||
275 | /* | |
276 | * walks the btree of allocated extents and find a hole of a given size. | |
277 | * The key ins is changed to record the hole: | |
278 | * ins->objectid == block start | |
62e2749e | 279 | * ins->flags = BTRFS_EXTENT_ITEM_KEY |
fec577fb CM |
280 | * ins->offset == number of blocks |
281 | * Any available blocks before search_start are skipped. | |
282 | */ | |
e089f05c CM |
283 | static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
284 | *orig_root, u64 num_blocks, u64 search_start, u64 | |
285 | search_end, struct btrfs_key *ins) | |
fec577fb | 286 | { |
234b63a0 | 287 | struct btrfs_path path; |
e2fa7227 | 288 | struct btrfs_key key; |
fec577fb CM |
289 | int ret; |
290 | u64 hole_size = 0; | |
291 | int slot = 0; | |
292 | u64 last_block; | |
037e6390 | 293 | u64 test_block; |
fec577fb | 294 | int start_found; |
234b63a0 | 295 | struct btrfs_leaf *l; |
9f5fae2f | 296 | struct btrfs_root * root = orig_root->fs_info->extent_root; |
0579da42 | 297 | int total_needed = num_blocks; |
fec577fb | 298 | |
7518a238 | 299 | total_needed += (btrfs_header_level(&root->node->node.header) + 1) * 3; |
9f5fae2f CM |
300 | if (root->fs_info->last_insert.objectid > search_start) |
301 | search_start = root->fs_info->last_insert.objectid; | |
62e2749e CM |
302 | |
303 | ins->flags = 0; | |
304 | btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY); | |
305 | ||
fec577fb | 306 | check_failed: |
234b63a0 | 307 | btrfs_init_path(&path); |
fec577fb CM |
308 | ins->objectid = search_start; |
309 | ins->offset = 0; | |
fec577fb | 310 | start_found = 0; |
e089f05c | 311 | ret = btrfs_search_slot(trans, root, ins, &path, 0, 0); |
0f70abe2 CM |
312 | if (ret < 0) |
313 | goto error; | |
aa5d6bed | 314 | |
0579da42 CM |
315 | if (path.slots[0] > 0) |
316 | path.slots[0]--; | |
317 | ||
fec577fb CM |
318 | while (1) { |
319 | l = &path.nodes[0]->leaf; | |
320 | slot = path.slots[0]; | |
7518a238 | 321 | if (slot >= btrfs_header_nritems(&l->header)) { |
234b63a0 | 322 | ret = btrfs_next_leaf(root, &path); |
fec577fb CM |
323 | if (ret == 0) |
324 | continue; | |
0f70abe2 CM |
325 | if (ret < 0) |
326 | goto error; | |
fec577fb CM |
327 | if (!start_found) { |
328 | ins->objectid = search_start; | |
037e6390 | 329 | ins->offset = (u64)-1; |
fec577fb CM |
330 | start_found = 1; |
331 | goto check_pending; | |
332 | } | |
333 | ins->objectid = last_block > search_start ? | |
334 | last_block : search_start; | |
037e6390 | 335 | ins->offset = (u64)-1; |
fec577fb CM |
336 | goto check_pending; |
337 | } | |
e2fa7227 CM |
338 | btrfs_disk_key_to_cpu(&key, &l->items[slot].key); |
339 | if (key.objectid >= search_start) { | |
fec577fb | 340 | if (start_found) { |
0579da42 CM |
341 | if (last_block < search_start) |
342 | last_block = search_start; | |
e2fa7227 | 343 | hole_size = key.objectid - last_block; |
037e6390 | 344 | if (hole_size > total_needed) { |
fec577fb | 345 | ins->objectid = last_block; |
037e6390 | 346 | ins->offset = hole_size; |
fec577fb CM |
347 | goto check_pending; |
348 | } | |
0579da42 | 349 | } |
fec577fb | 350 | } |
0579da42 | 351 | start_found = 1; |
e2fa7227 | 352 | last_block = key.objectid + key.offset; |
fec577fb CM |
353 | path.slots[0]++; |
354 | } | |
355 | // FIXME -ENOSPC | |
356 | check_pending: | |
357 | /* we have to make sure we didn't find an extent that has already | |
358 | * been allocated by the map tree or the original allocation | |
359 | */ | |
234b63a0 | 360 | btrfs_release_path(root, &path); |
fec577fb | 361 | BUG_ON(ins->objectid < search_start); |
037e6390 CM |
362 | for (test_block = ins->objectid; |
363 | test_block < ins->objectid + total_needed; test_block++) { | |
9f5fae2f CM |
364 | if (radix_tree_lookup(&root->fs_info->pinned_radix, |
365 | test_block)) { | |
037e6390 | 366 | search_start = test_block + 1; |
fec577fb CM |
367 | goto check_failed; |
368 | } | |
369 | } | |
9f5fae2f CM |
370 | BUG_ON(root->fs_info->current_insert.offset); |
371 | root->fs_info->current_insert.offset = total_needed - num_blocks; | |
372 | root->fs_info->current_insert.objectid = ins->objectid + num_blocks; | |
373 | root->fs_info->current_insert.flags = 0; | |
374 | root->fs_info->last_insert.objectid = ins->objectid; | |
037e6390 | 375 | ins->offset = num_blocks; |
fec577fb | 376 | return 0; |
0f70abe2 | 377 | error: |
234b63a0 | 378 | btrfs_release_path(root, &path); |
0f70abe2 | 379 | return ret; |
fec577fb CM |
380 | } |
381 | ||
fec577fb CM |
382 | /* |
383 | * finds a free extent and does all the dirty work required for allocation | |
384 | * returns the key for the extent through ins, and a tree buffer for | |
385 | * the first block of the extent through buf. | |
386 | * | |
387 | * returns 0 if everything worked, non-zero otherwise. | |
388 | */ | |
e089f05c CM |
389 | static int alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
390 | *root, u64 num_blocks, u64 search_start, u64 | |
391 | search_end, u64 owner, struct btrfs_key *ins) | |
fec577fb CM |
392 | { |
393 | int ret; | |
394 | int pending_ret; | |
9f5fae2f | 395 | struct btrfs_root *extent_root = root->fs_info->extent_root; |
234b63a0 | 396 | struct btrfs_extent_item extent_item; |
037e6390 | 397 | |
cf27e1ee CM |
398 | btrfs_set_extent_refs(&extent_item, 1); |
399 | btrfs_set_extent_owner(&extent_item, owner); | |
fec577fb | 400 | |
037e6390 | 401 | if (root == extent_root) { |
9f5fae2f | 402 | BUG_ON(extent_root->fs_info->current_insert.offset == 0); |
037e6390 | 403 | BUG_ON(num_blocks != 1); |
9f5fae2f CM |
404 | BUG_ON(extent_root->fs_info->current_insert.flags == |
405 | extent_root->fs_info->current_insert.offset); | |
037e6390 | 406 | ins->offset = 1; |
9f5fae2f CM |
407 | ins->objectid = extent_root->fs_info->current_insert.objectid + |
408 | extent_root->fs_info->current_insert.flags++; | |
fec577fb CM |
409 | return 0; |
410 | } | |
e089f05c | 411 | ret = find_free_extent(trans, root, num_blocks, search_start, |
037e6390 CM |
412 | search_end, ins); |
413 | if (ret) | |
414 | return ret; | |
fec577fb | 415 | |
e089f05c CM |
416 | ret = btrfs_insert_item(trans, extent_root, ins, &extent_item, |
417 | sizeof(extent_item)); | |
037e6390 | 418 | |
e089f05c CM |
419 | finish_current_insert(trans, extent_root); |
420 | pending_ret = run_pending(trans, extent_root); | |
037e6390 CM |
421 | if (ret) |
422 | return ret; | |
423 | if (pending_ret) | |
424 | return pending_ret; | |
425 | return 0; | |
fec577fb CM |
426 | } |
427 | ||
428 | /* | |
429 | * helper function to allocate a block for a given tree | |
430 | * returns the tree buffer or NULL. | |
431 | */ | |
e089f05c CM |
432 | struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans, |
433 | struct btrfs_root *root) | |
fec577fb | 434 | { |
e2fa7227 | 435 | struct btrfs_key ins; |
fec577fb | 436 | int ret; |
234b63a0 | 437 | struct btrfs_buffer *buf; |
fec577fb | 438 | |
e089f05c | 439 | ret = alloc_extent(trans, root, 1, 0, (unsigned long)-1, |
7518a238 | 440 | btrfs_header_parentid(&root->node->node.header), |
037e6390 | 441 | &ins); |
fec577fb CM |
442 | if (ret) { |
443 | BUG(); | |
444 | return NULL; | |
445 | } | |
037e6390 | 446 | buf = find_tree_block(root, ins.objectid); |
e089f05c | 447 | dirty_tree_block(trans, root, buf); |
fec577fb CM |
448 | return buf; |
449 | } | |
a28ec197 | 450 | |
9aca1d51 CM |
451 | /* |
452 | * helper function for drop_snapshot, this walks down the tree dropping ref | |
453 | * counts as it goes. | |
454 | */ | |
e089f05c CM |
455 | static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root |
456 | *root, struct btrfs_path *path, int *level) | |
20524f02 | 457 | { |
234b63a0 CM |
458 | struct btrfs_buffer *next; |
459 | struct btrfs_buffer *cur; | |
20524f02 CM |
460 | u64 blocknr; |
461 | int ret; | |
462 | u32 refs; | |
463 | ||
e089f05c CM |
464 | ret = lookup_block_ref(trans, root, path->nodes[*level]->blocknr, |
465 | &refs); | |
20524f02 CM |
466 | BUG_ON(ret); |
467 | if (refs > 1) | |
468 | goto out; | |
9aca1d51 CM |
469 | /* |
470 | * walk down to the last node level and free all the leaves | |
471 | */ | |
20524f02 CM |
472 | while(*level > 0) { |
473 | cur = path->nodes[*level]; | |
7518a238 CM |
474 | if (path->slots[*level] >= |
475 | btrfs_header_nritems(&cur->node.header)) | |
20524f02 | 476 | break; |
1d4f8a0c | 477 | blocknr = btrfs_node_blockptr(&cur->node, path->slots[*level]); |
e089f05c | 478 | ret = lookup_block_ref(trans, root, blocknr, &refs); |
20524f02 CM |
479 | if (refs != 1 || *level == 1) { |
480 | path->slots[*level]++; | |
e089f05c | 481 | ret = btrfs_free_extent(trans, root, blocknr, 1, 1); |
20524f02 CM |
482 | BUG_ON(ret); |
483 | continue; | |
484 | } | |
485 | BUG_ON(ret); | |
486 | next = read_tree_block(root, blocknr); | |
83e15a28 | 487 | if (path->nodes[*level-1]) |
234b63a0 | 488 | btrfs_block_release(root, path->nodes[*level-1]); |
20524f02 | 489 | path->nodes[*level-1] = next; |
7518a238 | 490 | *level = btrfs_header_level(&next->node.header); |
20524f02 CM |
491 | path->slots[*level] = 0; |
492 | } | |
493 | out: | |
e089f05c CM |
494 | ret = btrfs_free_extent(trans, root, path->nodes[*level]->blocknr, 1, |
495 | 1); | |
234b63a0 | 496 | btrfs_block_release(root, path->nodes[*level]); |
20524f02 CM |
497 | path->nodes[*level] = NULL; |
498 | *level += 1; | |
499 | BUG_ON(ret); | |
500 | return 0; | |
501 | } | |
502 | ||
9aca1d51 CM |
503 | /* |
504 | * helper for dropping snapshots. This walks back up the tree in the path | |
505 | * to find the first node higher up where we haven't yet gone through | |
506 | * all the slots | |
507 | */ | |
e089f05c CM |
508 | static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root |
509 | *root, struct btrfs_path *path, int *level) | |
20524f02 CM |
510 | { |
511 | int i; | |
512 | int slot; | |
513 | int ret; | |
234b63a0 | 514 | for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) { |
20524f02 | 515 | slot = path->slots[i]; |
7518a238 CM |
516 | if (slot < |
517 | btrfs_header_nritems(&path->nodes[i]->node.header)- 1) { | |
20524f02 CM |
518 | path->slots[i]++; |
519 | *level = i; | |
520 | return 0; | |
521 | } else { | |
e089f05c CM |
522 | ret = btrfs_free_extent(trans, root, |
523 | path->nodes[*level]->blocknr, | |
524 | 1, 1); | |
234b63a0 | 525 | btrfs_block_release(root, path->nodes[*level]); |
83e15a28 | 526 | path->nodes[*level] = NULL; |
20524f02 CM |
527 | *level = i + 1; |
528 | BUG_ON(ret); | |
529 | } | |
530 | } | |
531 | return 1; | |
532 | } | |
533 | ||
9aca1d51 CM |
534 | /* |
535 | * drop the reference count on the tree rooted at 'snap'. This traverses | |
536 | * the tree freeing any blocks that have a ref count of zero after being | |
537 | * decremented. | |
538 | */ | |
e089f05c CM |
539 | int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root |
540 | *root, struct btrfs_buffer *snap) | |
20524f02 | 541 | { |
3768f368 | 542 | int ret = 0; |
9aca1d51 | 543 | int wret; |
20524f02 | 544 | int level; |
234b63a0 | 545 | struct btrfs_path path; |
20524f02 CM |
546 | int i; |
547 | int orig_level; | |
548 | ||
234b63a0 | 549 | btrfs_init_path(&path); |
20524f02 | 550 | |
7518a238 | 551 | level = btrfs_header_level(&snap->node.header); |
20524f02 CM |
552 | orig_level = level; |
553 | path.nodes[level] = snap; | |
554 | path.slots[level] = 0; | |
555 | while(1) { | |
e089f05c | 556 | wret = walk_down_tree(trans, root, &path, &level); |
9aca1d51 | 557 | if (wret > 0) |
20524f02 | 558 | break; |
9aca1d51 CM |
559 | if (wret < 0) |
560 | ret = wret; | |
561 | ||
e089f05c | 562 | wret = walk_up_tree(trans, root, &path, &level); |
9aca1d51 | 563 | if (wret > 0) |
20524f02 | 564 | break; |
9aca1d51 CM |
565 | if (wret < 0) |
566 | ret = wret; | |
20524f02 | 567 | } |
83e15a28 CM |
568 | for (i = 0; i <= orig_level; i++) { |
569 | if (path.nodes[i]) { | |
234b63a0 | 570 | btrfs_block_release(root, path.nodes[i]); |
83e15a28 | 571 | } |
20524f02 | 572 | } |
9aca1d51 | 573 | return ret; |
20524f02 | 574 | } |