Commit | Line | Data |
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2e635a27 CM |
1 | #include <linux/module.h> |
2 | #include <linux/radix-tree.h> | |
fec577fb CM |
3 | #include "ctree.h" |
4 | #include "disk-io.h" | |
5 | #include "print-tree.h" | |
e089f05c | 6 | #include "transaction.h" |
fec577fb | 7 | |
e089f05c CM |
8 | static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
9 | *orig_root, u64 num_blocks, u64 search_start, u64 | |
10 | search_end, struct btrfs_key *ins); | |
11 | static int finish_current_insert(struct btrfs_trans_handle *trans, struct | |
12 | btrfs_root *extent_root); | |
e20d96d6 CM |
13 | static int del_pending_extents(struct btrfs_trans_handle *trans, struct |
14 | btrfs_root *extent_root); | |
fec577fb CM |
15 | /* |
16 | * pending extents are blocks that we're trying to allocate in the extent | |
17 | * map while trying to grow the map because of other allocations. To avoid | |
18 | * recursing, they are tagged in the radix tree and cleaned up after | |
19 | * other allocations are done. The pending tag is also used in the same | |
20 | * manner for deletes. | |
21 | */ | |
037e6390 | 22 | #define CTREE_EXTENT_PENDING_DEL 0 |
e20d96d6 | 23 | #define CTREE_EXTENT_PINNED 1 |
fec577fb | 24 | |
e089f05c CM |
25 | static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root |
26 | *root, u64 blocknr) | |
02217ed2 | 27 | { |
234b63a0 | 28 | struct btrfs_path path; |
02217ed2 | 29 | int ret; |
e2fa7227 | 30 | struct btrfs_key key; |
234b63a0 CM |
31 | struct btrfs_leaf *l; |
32 | struct btrfs_extent_item *item; | |
e2fa7227 | 33 | struct btrfs_key ins; |
cf27e1ee | 34 | u32 refs; |
037e6390 | 35 | |
9f5fae2f CM |
36 | find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1, |
37 | &ins); | |
234b63a0 | 38 | btrfs_init_path(&path); |
02217ed2 CM |
39 | key.objectid = blocknr; |
40 | key.flags = 0; | |
62e2749e | 41 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); |
02217ed2 | 42 | key.offset = 1; |
9f5fae2f CM |
43 | ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path, |
44 | 0, 1); | |
a28ec197 CM |
45 | if (ret != 0) |
46 | BUG(); | |
02217ed2 | 47 | BUG_ON(ret != 0); |
e20d96d6 | 48 | l = btrfs_buffer_leaf(path.nodes[0]); |
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 | |
9f5fae2f CM |
53 | btrfs_release_path(root->fs_info->extent_root, &path); |
54 | finish_current_insert(trans, root->fs_info->extent_root); | |
e20d96d6 | 55 | del_pending_extents(trans, root->fs_info->extent_root); |
02217ed2 CM |
56 | return 0; |
57 | } | |
58 | ||
e089f05c CM |
59 | static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root |
60 | *root, u64 blocknr, u32 *refs) | |
a28ec197 | 61 | { |
234b63a0 | 62 | struct btrfs_path path; |
a28ec197 | 63 | int ret; |
e2fa7227 | 64 | struct btrfs_key key; |
234b63a0 CM |
65 | struct btrfs_leaf *l; |
66 | struct btrfs_extent_item *item; | |
67 | btrfs_init_path(&path); | |
a28ec197 | 68 | key.objectid = blocknr; |
a28ec197 | 69 | key.offset = 1; |
62e2749e CM |
70 | key.flags = 0; |
71 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); | |
9f5fae2f CM |
72 | ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path, |
73 | 0, 0); | |
a28ec197 CM |
74 | if (ret != 0) |
75 | BUG(); | |
e20d96d6 | 76 | l = btrfs_buffer_leaf(path.nodes[0]); |
4beb1b8b | 77 | item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item); |
cf27e1ee | 78 | *refs = btrfs_extent_refs(item); |
9f5fae2f | 79 | btrfs_release_path(root->fs_info->extent_root, &path); |
a28ec197 CM |
80 | return 0; |
81 | } | |
82 | ||
e089f05c | 83 | int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
e20d96d6 | 84 | struct buffer_head *buf) |
02217ed2 CM |
85 | { |
86 | u64 blocknr; | |
e20d96d6 | 87 | struct btrfs_node *buf_node; |
02217ed2 | 88 | int i; |
a28ec197 | 89 | |
3768f368 | 90 | if (!root->ref_cows) |
a28ec197 | 91 | return 0; |
e20d96d6 CM |
92 | buf_node = btrfs_buffer_node(buf); |
93 | if (btrfs_is_leaf(buf_node)) | |
a28ec197 CM |
94 | return 0; |
95 | ||
e20d96d6 CM |
96 | for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) { |
97 | blocknr = btrfs_node_blockptr(buf_node, i); | |
e089f05c | 98 | inc_block_ref(trans, root, blocknr); |
02217ed2 CM |
99 | } |
100 | return 0; | |
101 | } | |
102 | ||
e089f05c CM |
103 | int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct |
104 | btrfs_root *root) | |
a28ec197 | 105 | { |
a28ec197 | 106 | unsigned long gang[8]; |
88fd146c | 107 | u64 first = 0; |
a28ec197 CM |
108 | int ret; |
109 | int i; | |
110 | ||
111 | while(1) { | |
e20d96d6 | 112 | ret = radix_tree_gang_lookup_tag(&root->fs_info->pinned_radix, |
9f5fae2f | 113 | (void **)gang, 0, |
e20d96d6 CM |
114 | ARRAY_SIZE(gang), |
115 | CTREE_EXTENT_PINNED); | |
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; | |
1261ec42 CM |
137 | u64 super_blocks_used; |
138 | struct btrfs_fs_info *info = extent_root->fs_info; | |
037e6390 | 139 | |
cf27e1ee CM |
140 | btrfs_set_extent_refs(&extent_item, 1); |
141 | btrfs_set_extent_owner(&extent_item, | |
e20d96d6 | 142 | btrfs_header_parentid(btrfs_buffer_header(extent_root->node))); |
037e6390 CM |
143 | ins.offset = 1; |
144 | ins.flags = 0; | |
62e2749e | 145 | btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY); |
037e6390 | 146 | |
9f5fae2f CM |
147 | for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) { |
148 | ins.objectid = extent_root->fs_info->current_insert.objectid + | |
149 | i; | |
1261ec42 CM |
150 | super_blocks_used = btrfs_super_blocks_used(info->disk_super); |
151 | btrfs_set_super_blocks_used(info->disk_super, | |
152 | super_blocks_used + 1); | |
e089f05c CM |
153 | ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item, |
154 | sizeof(extent_item)); | |
037e6390 CM |
155 | BUG_ON(ret); |
156 | } | |
9f5fae2f | 157 | extent_root->fs_info->current_insert.offset = 0; |
037e6390 CM |
158 | return 0; |
159 | } | |
160 | ||
e20d96d6 CM |
161 | static int pin_down_block(struct btrfs_root *root, u64 blocknr, int tag) |
162 | { | |
163 | int err; | |
164 | err = radix_tree_insert(&root->fs_info->pinned_radix, | |
165 | blocknr, (void *)blocknr); | |
166 | BUG_ON(err); | |
167 | if (err) | |
168 | return err; | |
169 | radix_tree_tag_set(&root->fs_info->pinned_radix, blocknr, | |
170 | tag); | |
171 | return 0; | |
172 | } | |
173 | ||
fec577fb | 174 | /* |
a28ec197 | 175 | * remove an extent from the root, returns 0 on success |
fec577fb | 176 | */ |
e089f05c | 177 | static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
e20d96d6 | 178 | *root, u64 blocknr, u64 num_blocks) |
a28ec197 | 179 | { |
234b63a0 | 180 | struct btrfs_path path; |
e2fa7227 | 181 | struct btrfs_key key; |
1261ec42 CM |
182 | struct btrfs_fs_info *info = root->fs_info; |
183 | struct btrfs_root *extent_root = info->extent_root; | |
a28ec197 | 184 | int ret; |
234b63a0 | 185 | struct btrfs_extent_item *ei; |
e2fa7227 | 186 | struct btrfs_key ins; |
cf27e1ee | 187 | u32 refs; |
037e6390 | 188 | |
a28ec197 CM |
189 | key.objectid = blocknr; |
190 | key.flags = 0; | |
62e2749e | 191 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); |
a28ec197 CM |
192 | key.offset = num_blocks; |
193 | ||
e089f05c | 194 | find_free_extent(trans, root, 0, 0, (u64)-1, &ins); |
234b63a0 | 195 | btrfs_init_path(&path); |
e089f05c | 196 | ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1); |
a28ec197 | 197 | if (ret) { |
2e635a27 | 198 | printk("failed to find %Lu\n", key.objectid); |
234b63a0 | 199 | btrfs_print_tree(extent_root, extent_root->node); |
2e635a27 | 200 | printk("failed to find %Lu\n", key.objectid); |
a28ec197 CM |
201 | BUG(); |
202 | } | |
e20d96d6 | 203 | ei = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0], |
123abc88 | 204 | struct btrfs_extent_item); |
a28ec197 | 205 | BUG_ON(ei->refs == 0); |
cf27e1ee CM |
206 | refs = btrfs_extent_refs(ei) - 1; |
207 | btrfs_set_extent_refs(ei, refs); | |
208 | if (refs == 0) { | |
1261ec42 | 209 | u64 super_blocks_used; |
1261ec42 CM |
210 | super_blocks_used = btrfs_super_blocks_used(info->disk_super); |
211 | btrfs_set_super_blocks_used(info->disk_super, | |
212 | super_blocks_used - num_blocks); | |
e089f05c | 213 | ret = btrfs_del_item(trans, extent_root, &path); |
e20d96d6 | 214 | if (extent_root->fs_info->last_insert.objectid > |
9f5fae2f CM |
215 | blocknr) |
216 | extent_root->fs_info->last_insert.objectid = blocknr; | |
a28ec197 CM |
217 | if (ret) |
218 | BUG(); | |
219 | } | |
234b63a0 | 220 | btrfs_release_path(extent_root, &path); |
e089f05c | 221 | finish_current_insert(trans, extent_root); |
a28ec197 CM |
222 | return ret; |
223 | } | |
224 | ||
a28ec197 CM |
225 | /* |
226 | * find all the blocks marked as pending in the radix tree and remove | |
227 | * them from the extent map | |
228 | */ | |
e089f05c CM |
229 | static int del_pending_extents(struct btrfs_trans_handle *trans, struct |
230 | btrfs_root *extent_root) | |
a28ec197 CM |
231 | { |
232 | int ret; | |
e20d96d6 CM |
233 | int wret; |
234 | int err = 0; | |
235 | unsigned long gang[4]; | |
a28ec197 | 236 | int i; |
e20d96d6 | 237 | struct radix_tree_root *radix = &extent_root->fs_info->pinned_radix; |
a28ec197 CM |
238 | |
239 | while(1) { | |
9f5fae2f | 240 | ret = radix_tree_gang_lookup_tag( |
e20d96d6 | 241 | &extent_root->fs_info->pinned_radix, |
9f5fae2f CM |
242 | (void **)gang, 0, |
243 | ARRAY_SIZE(gang), | |
244 | CTREE_EXTENT_PENDING_DEL); | |
a28ec197 CM |
245 | if (!ret) |
246 | break; | |
247 | for (i = 0; i < ret; i++) { | |
e20d96d6 CM |
248 | radix_tree_tag_set(radix, gang[i], CTREE_EXTENT_PINNED); |
249 | radix_tree_tag_clear(radix, gang[i], | |
9f5fae2f | 250 | CTREE_EXTENT_PENDING_DEL); |
e20d96d6 CM |
251 | wret = __free_extent(trans, extent_root, gang[i], 1); |
252 | if (wret) | |
253 | err = wret; | |
fec577fb CM |
254 | } |
255 | } | |
e20d96d6 | 256 | return err; |
fec577fb CM |
257 | } |
258 | ||
259 | /* | |
260 | * remove an extent from the root, returns 0 on success | |
261 | */ | |
e089f05c CM |
262 | int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
263 | *root, u64 blocknr, u64 num_blocks, int pin) | |
fec577fb | 264 | { |
9f5fae2f | 265 | struct btrfs_root *extent_root = root->fs_info->extent_root; |
e20d96d6 | 266 | struct buffer_head *t; |
fec577fb CM |
267 | int pending_ret; |
268 | int ret; | |
a28ec197 | 269 | |
fec577fb | 270 | if (root == extent_root) { |
a28ec197 | 271 | t = find_tree_block(root, blocknr); |
e20d96d6 | 272 | pin_down_block(root, blocknr, CTREE_EXTENT_PENDING_DEL); |
fec577fb CM |
273 | return 0; |
274 | } | |
e20d96d6 CM |
275 | if (pin) { |
276 | ret = pin_down_block(root, blocknr, CTREE_EXTENT_PINNED); | |
277 | BUG_ON(ret); | |
278 | } | |
279 | ret = __free_extent(trans, root, blocknr, num_blocks); | |
280 | pending_ret = del_pending_extents(trans, root->fs_info->extent_root); | |
fec577fb CM |
281 | return ret ? ret : pending_ret; |
282 | } | |
283 | ||
284 | /* | |
285 | * walks the btree of allocated extents and find a hole of a given size. | |
286 | * The key ins is changed to record the hole: | |
287 | * ins->objectid == block start | |
62e2749e | 288 | * ins->flags = BTRFS_EXTENT_ITEM_KEY |
fec577fb CM |
289 | * ins->offset == number of blocks |
290 | * Any available blocks before search_start are skipped. | |
291 | */ | |
e089f05c CM |
292 | static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
293 | *orig_root, u64 num_blocks, u64 search_start, u64 | |
294 | search_end, struct btrfs_key *ins) | |
fec577fb | 295 | { |
234b63a0 | 296 | struct btrfs_path path; |
e2fa7227 | 297 | struct btrfs_key key; |
fec577fb CM |
298 | int ret; |
299 | u64 hole_size = 0; | |
300 | int slot = 0; | |
e20d96d6 | 301 | u64 last_block = 0; |
037e6390 | 302 | u64 test_block; |
fec577fb | 303 | int start_found; |
234b63a0 | 304 | struct btrfs_leaf *l; |
9f5fae2f | 305 | struct btrfs_root * root = orig_root->fs_info->extent_root; |
0579da42 | 306 | int total_needed = num_blocks; |
e20d96d6 | 307 | int level; |
fec577fb | 308 | |
e20d96d6 CM |
309 | level = btrfs_header_level(btrfs_buffer_header(root->node)); |
310 | total_needed += (level + 1) * 3; | |
9f5fae2f CM |
311 | if (root->fs_info->last_insert.objectid > search_start) |
312 | search_start = root->fs_info->last_insert.objectid; | |
62e2749e CM |
313 | |
314 | ins->flags = 0; | |
315 | btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY); | |
316 | ||
fec577fb | 317 | check_failed: |
234b63a0 | 318 | btrfs_init_path(&path); |
fec577fb CM |
319 | ins->objectid = search_start; |
320 | ins->offset = 0; | |
fec577fb | 321 | start_found = 0; |
e089f05c | 322 | ret = btrfs_search_slot(trans, root, ins, &path, 0, 0); |
0f70abe2 CM |
323 | if (ret < 0) |
324 | goto error; | |
aa5d6bed | 325 | |
0579da42 CM |
326 | if (path.slots[0] > 0) |
327 | path.slots[0]--; | |
328 | ||
fec577fb | 329 | while (1) { |
e20d96d6 | 330 | l = btrfs_buffer_leaf(path.nodes[0]); |
fec577fb | 331 | slot = path.slots[0]; |
7518a238 | 332 | if (slot >= btrfs_header_nritems(&l->header)) { |
234b63a0 | 333 | ret = btrfs_next_leaf(root, &path); |
fec577fb CM |
334 | if (ret == 0) |
335 | continue; | |
0f70abe2 CM |
336 | if (ret < 0) |
337 | goto error; | |
fec577fb CM |
338 | if (!start_found) { |
339 | ins->objectid = search_start; | |
037e6390 | 340 | ins->offset = (u64)-1; |
fec577fb CM |
341 | start_found = 1; |
342 | goto check_pending; | |
343 | } | |
344 | ins->objectid = last_block > search_start ? | |
345 | last_block : search_start; | |
037e6390 | 346 | ins->offset = (u64)-1; |
fec577fb CM |
347 | goto check_pending; |
348 | } | |
e2fa7227 CM |
349 | btrfs_disk_key_to_cpu(&key, &l->items[slot].key); |
350 | if (key.objectid >= search_start) { | |
fec577fb | 351 | if (start_found) { |
0579da42 CM |
352 | if (last_block < search_start) |
353 | last_block = search_start; | |
e2fa7227 | 354 | hole_size = key.objectid - last_block; |
037e6390 | 355 | if (hole_size > total_needed) { |
fec577fb | 356 | ins->objectid = last_block; |
037e6390 | 357 | ins->offset = hole_size; |
fec577fb CM |
358 | goto check_pending; |
359 | } | |
0579da42 | 360 | } |
fec577fb | 361 | } |
0579da42 | 362 | start_found = 1; |
e2fa7227 | 363 | last_block = key.objectid + key.offset; |
fec577fb CM |
364 | path.slots[0]++; |
365 | } | |
366 | // FIXME -ENOSPC | |
367 | check_pending: | |
368 | /* we have to make sure we didn't find an extent that has already | |
369 | * been allocated by the map tree or the original allocation | |
370 | */ | |
234b63a0 | 371 | btrfs_release_path(root, &path); |
fec577fb | 372 | BUG_ON(ins->objectid < search_start); |
037e6390 CM |
373 | for (test_block = ins->objectid; |
374 | test_block < ins->objectid + total_needed; test_block++) { | |
9f5fae2f CM |
375 | if (radix_tree_lookup(&root->fs_info->pinned_radix, |
376 | test_block)) { | |
037e6390 | 377 | search_start = test_block + 1; |
fec577fb CM |
378 | goto check_failed; |
379 | } | |
380 | } | |
9f5fae2f CM |
381 | BUG_ON(root->fs_info->current_insert.offset); |
382 | root->fs_info->current_insert.offset = total_needed - num_blocks; | |
383 | root->fs_info->current_insert.objectid = ins->objectid + num_blocks; | |
384 | root->fs_info->current_insert.flags = 0; | |
385 | root->fs_info->last_insert.objectid = ins->objectid; | |
037e6390 | 386 | ins->offset = num_blocks; |
fec577fb | 387 | return 0; |
0f70abe2 | 388 | error: |
234b63a0 | 389 | btrfs_release_path(root, &path); |
0f70abe2 | 390 | return ret; |
fec577fb CM |
391 | } |
392 | ||
fec577fb CM |
393 | /* |
394 | * finds a free extent and does all the dirty work required for allocation | |
395 | * returns the key for the extent through ins, and a tree buffer for | |
396 | * the first block of the extent through buf. | |
397 | * | |
398 | * returns 0 if everything worked, non-zero otherwise. | |
399 | */ | |
e089f05c CM |
400 | static int alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
401 | *root, u64 num_blocks, u64 search_start, u64 | |
402 | search_end, u64 owner, struct btrfs_key *ins) | |
fec577fb CM |
403 | { |
404 | int ret; | |
405 | int pending_ret; | |
1261ec42 CM |
406 | u64 super_blocks_used; |
407 | struct btrfs_fs_info *info = root->fs_info; | |
408 | struct btrfs_root *extent_root = info->extent_root; | |
234b63a0 | 409 | struct btrfs_extent_item extent_item; |
037e6390 | 410 | |
cf27e1ee CM |
411 | btrfs_set_extent_refs(&extent_item, 1); |
412 | btrfs_set_extent_owner(&extent_item, owner); | |
fec577fb | 413 | |
037e6390 | 414 | if (root == extent_root) { |
9f5fae2f | 415 | BUG_ON(extent_root->fs_info->current_insert.offset == 0); |
037e6390 | 416 | BUG_ON(num_blocks != 1); |
9f5fae2f CM |
417 | BUG_ON(extent_root->fs_info->current_insert.flags == |
418 | extent_root->fs_info->current_insert.offset); | |
037e6390 | 419 | ins->offset = 1; |
9f5fae2f CM |
420 | ins->objectid = extent_root->fs_info->current_insert.objectid + |
421 | extent_root->fs_info->current_insert.flags++; | |
fec577fb CM |
422 | return 0; |
423 | } | |
e089f05c | 424 | ret = find_free_extent(trans, root, num_blocks, search_start, |
037e6390 CM |
425 | search_end, ins); |
426 | if (ret) | |
427 | return ret; | |
fec577fb | 428 | |
1261ec42 CM |
429 | super_blocks_used = btrfs_super_blocks_used(info->disk_super); |
430 | btrfs_set_super_blocks_used(info->disk_super, super_blocks_used + | |
431 | num_blocks); | |
e089f05c CM |
432 | ret = btrfs_insert_item(trans, extent_root, ins, &extent_item, |
433 | sizeof(extent_item)); | |
037e6390 | 434 | |
e089f05c | 435 | finish_current_insert(trans, extent_root); |
e20d96d6 | 436 | pending_ret = del_pending_extents(trans, extent_root); |
037e6390 CM |
437 | if (ret) |
438 | return ret; | |
439 | if (pending_ret) | |
440 | return pending_ret; | |
441 | return 0; | |
fec577fb CM |
442 | } |
443 | ||
444 | /* | |
445 | * helper function to allocate a block for a given tree | |
446 | * returns the tree buffer or NULL. | |
447 | */ | |
e20d96d6 | 448 | struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans, |
e089f05c | 449 | struct btrfs_root *root) |
fec577fb | 450 | { |
e2fa7227 | 451 | struct btrfs_key ins; |
fec577fb | 452 | int ret; |
e20d96d6 | 453 | struct buffer_head *buf; |
fec577fb | 454 | |
e089f05c | 455 | ret = alloc_extent(trans, root, 1, 0, (unsigned long)-1, |
e20d96d6 | 456 | btrfs_header_parentid(btrfs_buffer_header(root->node)), &ins); |
fec577fb CM |
457 | if (ret) { |
458 | BUG(); | |
459 | return NULL; | |
460 | } | |
037e6390 | 461 | buf = find_tree_block(root, ins.objectid); |
e089f05c | 462 | dirty_tree_block(trans, root, buf); |
fec577fb CM |
463 | return buf; |
464 | } | |
a28ec197 | 465 | |
9aca1d51 CM |
466 | /* |
467 | * helper function for drop_snapshot, this walks down the tree dropping ref | |
468 | * counts as it goes. | |
469 | */ | |
e089f05c CM |
470 | static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root |
471 | *root, struct btrfs_path *path, int *level) | |
20524f02 | 472 | { |
e20d96d6 CM |
473 | struct buffer_head *next; |
474 | struct buffer_head *cur; | |
20524f02 CM |
475 | u64 blocknr; |
476 | int ret; | |
477 | u32 refs; | |
478 | ||
e20d96d6 | 479 | ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr, |
e089f05c | 480 | &refs); |
20524f02 CM |
481 | BUG_ON(ret); |
482 | if (refs > 1) | |
483 | goto out; | |
9aca1d51 CM |
484 | /* |
485 | * walk down to the last node level and free all the leaves | |
486 | */ | |
20524f02 CM |
487 | while(*level > 0) { |
488 | cur = path->nodes[*level]; | |
7518a238 | 489 | if (path->slots[*level] >= |
e20d96d6 | 490 | btrfs_header_nritems(btrfs_buffer_header(cur))) |
20524f02 | 491 | break; |
e20d96d6 CM |
492 | blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur), |
493 | path->slots[*level]); | |
e089f05c | 494 | ret = lookup_block_ref(trans, root, blocknr, &refs); |
20524f02 CM |
495 | if (refs != 1 || *level == 1) { |
496 | path->slots[*level]++; | |
e089f05c | 497 | ret = btrfs_free_extent(trans, root, blocknr, 1, 1); |
20524f02 CM |
498 | BUG_ON(ret); |
499 | continue; | |
500 | } | |
501 | BUG_ON(ret); | |
502 | next = read_tree_block(root, blocknr); | |
83e15a28 | 503 | if (path->nodes[*level-1]) |
234b63a0 | 504 | btrfs_block_release(root, path->nodes[*level-1]); |
20524f02 | 505 | path->nodes[*level-1] = next; |
e20d96d6 | 506 | *level = btrfs_header_level(btrfs_buffer_header(next)); |
20524f02 CM |
507 | path->slots[*level] = 0; |
508 | } | |
509 | out: | |
e20d96d6 CM |
510 | ret = btrfs_free_extent(trans, root, path->nodes[*level]->b_blocknr, |
511 | 1, 1); | |
234b63a0 | 512 | btrfs_block_release(root, path->nodes[*level]); |
20524f02 CM |
513 | path->nodes[*level] = NULL; |
514 | *level += 1; | |
515 | BUG_ON(ret); | |
516 | return 0; | |
517 | } | |
518 | ||
9aca1d51 CM |
519 | /* |
520 | * helper for dropping snapshots. This walks back up the tree in the path | |
521 | * to find the first node higher up where we haven't yet gone through | |
522 | * all the slots | |
523 | */ | |
e089f05c CM |
524 | static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root |
525 | *root, struct btrfs_path *path, int *level) | |
20524f02 CM |
526 | { |
527 | int i; | |
528 | int slot; | |
529 | int ret; | |
234b63a0 | 530 | for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) { |
20524f02 | 531 | slot = path->slots[i]; |
e20d96d6 CM |
532 | if (slot < btrfs_header_nritems( |
533 | btrfs_buffer_header(path->nodes[i])) - 1) { | |
20524f02 CM |
534 | path->slots[i]++; |
535 | *level = i; | |
536 | return 0; | |
537 | } else { | |
e089f05c | 538 | ret = btrfs_free_extent(trans, root, |
e20d96d6 | 539 | path->nodes[*level]->b_blocknr, |
e089f05c | 540 | 1, 1); |
234b63a0 | 541 | btrfs_block_release(root, path->nodes[*level]); |
83e15a28 | 542 | path->nodes[*level] = NULL; |
20524f02 CM |
543 | *level = i + 1; |
544 | BUG_ON(ret); | |
545 | } | |
546 | } | |
547 | return 1; | |
548 | } | |
549 | ||
9aca1d51 CM |
550 | /* |
551 | * drop the reference count on the tree rooted at 'snap'. This traverses | |
552 | * the tree freeing any blocks that have a ref count of zero after being | |
553 | * decremented. | |
554 | */ | |
e089f05c | 555 | int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root |
e20d96d6 | 556 | *root, struct buffer_head *snap) |
20524f02 | 557 | { |
3768f368 | 558 | int ret = 0; |
9aca1d51 | 559 | int wret; |
20524f02 | 560 | int level; |
234b63a0 | 561 | struct btrfs_path path; |
20524f02 CM |
562 | int i; |
563 | int orig_level; | |
564 | ||
234b63a0 | 565 | btrfs_init_path(&path); |
20524f02 | 566 | |
e20d96d6 | 567 | level = btrfs_header_level(btrfs_buffer_header(snap)); |
20524f02 CM |
568 | orig_level = level; |
569 | path.nodes[level] = snap; | |
570 | path.slots[level] = 0; | |
571 | while(1) { | |
e089f05c | 572 | wret = walk_down_tree(trans, root, &path, &level); |
9aca1d51 | 573 | if (wret > 0) |
20524f02 | 574 | break; |
9aca1d51 CM |
575 | if (wret < 0) |
576 | ret = wret; | |
577 | ||
e089f05c | 578 | wret = walk_up_tree(trans, root, &path, &level); |
9aca1d51 | 579 | if (wret > 0) |
20524f02 | 580 | break; |
9aca1d51 CM |
581 | if (wret < 0) |
582 | ret = wret; | |
20524f02 | 583 | } |
83e15a28 CM |
584 | for (i = 0; i <= orig_level; i++) { |
585 | if (path.nodes[i]) { | |
234b63a0 | 586 | btrfs_block_release(root, path.nodes[i]); |
83e15a28 | 587 | } |
20524f02 | 588 | } |
9aca1d51 | 589 | return ret; |
20524f02 | 590 | } |