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