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); | |
d5719762 | 52 | mark_buffer_dirty(path.nodes[0]); |
a28ec197 | 53 | |
9f5fae2f CM |
54 | btrfs_release_path(root->fs_info->extent_root, &path); |
55 | finish_current_insert(trans, root->fs_info->extent_root); | |
e20d96d6 | 56 | del_pending_extents(trans, root->fs_info->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); | |
9f5fae2f CM |
73 | ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path, |
74 | 0, 0); | |
a28ec197 CM |
75 | if (ret != 0) |
76 | BUG(); | |
e20d96d6 | 77 | l = btrfs_buffer_leaf(path.nodes[0]); |
4beb1b8b | 78 | item = btrfs_item_ptr(l, path.slots[0], struct btrfs_extent_item); |
cf27e1ee | 79 | *refs = btrfs_extent_refs(item); |
9f5fae2f | 80 | btrfs_release_path(root->fs_info->extent_root, &path); |
a28ec197 CM |
81 | return 0; |
82 | } | |
83 | ||
e089f05c | 84 | int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
e20d96d6 | 85 | struct buffer_head *buf) |
02217ed2 CM |
86 | { |
87 | u64 blocknr; | |
e20d96d6 | 88 | struct btrfs_node *buf_node; |
02217ed2 | 89 | int i; |
a28ec197 | 90 | |
3768f368 | 91 | if (!root->ref_cows) |
a28ec197 | 92 | return 0; |
e20d96d6 CM |
93 | buf_node = btrfs_buffer_node(buf); |
94 | if (btrfs_is_leaf(buf_node)) | |
a28ec197 CM |
95 | return 0; |
96 | ||
e20d96d6 CM |
97 | for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) { |
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 | { |
d5719762 | 107 | struct buffer_head *gang[8]; |
88fd146c | 108 | u64 first = 0; |
a28ec197 CM |
109 | int ret; |
110 | int i; | |
111 | ||
112 | while(1) { | |
e20d96d6 | 113 | ret = radix_tree_gang_lookup_tag(&root->fs_info->pinned_radix, |
9f5fae2f | 114 | (void **)gang, 0, |
e20d96d6 CM |
115 | ARRAY_SIZE(gang), |
116 | CTREE_EXTENT_PINNED); | |
a28ec197 CM |
117 | if (!ret) |
118 | break; | |
88fd146c | 119 | if (!first) |
d5719762 | 120 | first = gang[0]->b_blocknr; |
0579da42 | 121 | for (i = 0; i < ret; i++) { |
9f5fae2f | 122 | radix_tree_delete(&root->fs_info->pinned_radix, |
d5719762 CM |
123 | gang[i]->b_blocknr); |
124 | brelse(gang[i]); | |
0579da42 | 125 | } |
a28ec197 | 126 | } |
d5719762 CM |
127 | if (root->fs_info->last_insert.objectid > first) |
128 | root->fs_info->last_insert.objectid = first; | |
9f5fae2f | 129 | root->fs_info->last_insert.offset = 0; |
a28ec197 CM |
130 | return 0; |
131 | } | |
132 | ||
e089f05c CM |
133 | static int finish_current_insert(struct btrfs_trans_handle *trans, struct |
134 | btrfs_root *extent_root) | |
037e6390 | 135 | { |
e2fa7227 | 136 | struct btrfs_key ins; |
234b63a0 | 137 | struct btrfs_extent_item extent_item; |
037e6390 CM |
138 | int i; |
139 | int ret; | |
1261ec42 CM |
140 | u64 super_blocks_used; |
141 | struct btrfs_fs_info *info = extent_root->fs_info; | |
037e6390 | 142 | |
cf27e1ee CM |
143 | btrfs_set_extent_refs(&extent_item, 1); |
144 | btrfs_set_extent_owner(&extent_item, | |
e20d96d6 | 145 | btrfs_header_parentid(btrfs_buffer_header(extent_root->node))); |
037e6390 CM |
146 | ins.offset = 1; |
147 | ins.flags = 0; | |
62e2749e | 148 | btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY); |
037e6390 | 149 | |
9f5fae2f CM |
150 | for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) { |
151 | ins.objectid = extent_root->fs_info->current_insert.objectid + | |
152 | i; | |
1261ec42 CM |
153 | super_blocks_used = btrfs_super_blocks_used(info->disk_super); |
154 | btrfs_set_super_blocks_used(info->disk_super, | |
155 | super_blocks_used + 1); | |
e089f05c CM |
156 | ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item, |
157 | sizeof(extent_item)); | |
037e6390 CM |
158 | BUG_ON(ret); |
159 | } | |
9f5fae2f | 160 | extent_root->fs_info->current_insert.offset = 0; |
037e6390 CM |
161 | return 0; |
162 | } | |
163 | ||
e20d96d6 CM |
164 | static int pin_down_block(struct btrfs_root *root, u64 blocknr, int tag) |
165 | { | |
166 | int err; | |
d5719762 CM |
167 | struct buffer_head *bh = sb_getblk(root->fs_info->sb, blocknr); |
168 | BUG_ON(!bh); | |
e20d96d6 | 169 | err = radix_tree_insert(&root->fs_info->pinned_radix, |
d5719762 | 170 | blocknr, bh); |
d561c025 CM |
171 | if (err && err != -EEXIST) { |
172 | BUG(); | |
e20d96d6 | 173 | return err; |
d561c025 | 174 | } |
e20d96d6 CM |
175 | radix_tree_tag_set(&root->fs_info->pinned_radix, blocknr, |
176 | tag); | |
177 | return 0; | |
178 | } | |
179 | ||
fec577fb | 180 | /* |
a28ec197 | 181 | * remove an extent from the root, returns 0 on success |
fec577fb | 182 | */ |
e089f05c | 183 | static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
e20d96d6 | 184 | *root, u64 blocknr, u64 num_blocks) |
a28ec197 | 185 | { |
234b63a0 | 186 | struct btrfs_path path; |
e2fa7227 | 187 | struct btrfs_key key; |
1261ec42 CM |
188 | struct btrfs_fs_info *info = root->fs_info; |
189 | struct btrfs_root *extent_root = info->extent_root; | |
a28ec197 | 190 | int ret; |
234b63a0 | 191 | struct btrfs_extent_item *ei; |
e2fa7227 | 192 | struct btrfs_key ins; |
cf27e1ee | 193 | u32 refs; |
037e6390 | 194 | |
a28ec197 CM |
195 | key.objectid = blocknr; |
196 | key.flags = 0; | |
62e2749e | 197 | btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY); |
a28ec197 CM |
198 | key.offset = num_blocks; |
199 | ||
e089f05c | 200 | find_free_extent(trans, root, 0, 0, (u64)-1, &ins); |
234b63a0 | 201 | btrfs_init_path(&path); |
e089f05c | 202 | ret = btrfs_search_slot(trans, extent_root, &key, &path, -1, 1); |
a28ec197 | 203 | if (ret) { |
2e635a27 | 204 | printk("failed to find %Lu\n", key.objectid); |
234b63a0 | 205 | btrfs_print_tree(extent_root, extent_root->node); |
2e635a27 | 206 | printk("failed to find %Lu\n", key.objectid); |
a28ec197 CM |
207 | BUG(); |
208 | } | |
e20d96d6 | 209 | ei = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0], |
123abc88 | 210 | struct btrfs_extent_item); |
a28ec197 | 211 | BUG_ON(ei->refs == 0); |
cf27e1ee CM |
212 | refs = btrfs_extent_refs(ei) - 1; |
213 | btrfs_set_extent_refs(ei, refs); | |
214 | if (refs == 0) { | |
1261ec42 | 215 | u64 super_blocks_used; |
1261ec42 CM |
216 | super_blocks_used = btrfs_super_blocks_used(info->disk_super); |
217 | btrfs_set_super_blocks_used(info->disk_super, | |
218 | super_blocks_used - num_blocks); | |
e089f05c | 219 | ret = btrfs_del_item(trans, extent_root, &path); |
e20d96d6 | 220 | if (extent_root->fs_info->last_insert.objectid > |
9f5fae2f CM |
221 | blocknr) |
222 | extent_root->fs_info->last_insert.objectid = blocknr; | |
a28ec197 CM |
223 | if (ret) |
224 | BUG(); | |
225 | } | |
d5719762 | 226 | mark_buffer_dirty(path.nodes[0]); |
234b63a0 | 227 | btrfs_release_path(extent_root, &path); |
e089f05c | 228 | finish_current_insert(trans, extent_root); |
a28ec197 CM |
229 | return ret; |
230 | } | |
231 | ||
a28ec197 CM |
232 | /* |
233 | * find all the blocks marked as pending in the radix tree and remove | |
234 | * them from the extent map | |
235 | */ | |
e089f05c CM |
236 | static int del_pending_extents(struct btrfs_trans_handle *trans, struct |
237 | btrfs_root *extent_root) | |
a28ec197 CM |
238 | { |
239 | int ret; | |
e20d96d6 CM |
240 | int wret; |
241 | int err = 0; | |
d5719762 | 242 | struct buffer_head *gang[4]; |
a28ec197 | 243 | int i; |
e20d96d6 | 244 | struct radix_tree_root *radix = &extent_root->fs_info->pinned_radix; |
a28ec197 CM |
245 | |
246 | while(1) { | |
9f5fae2f | 247 | ret = radix_tree_gang_lookup_tag( |
e20d96d6 | 248 | &extent_root->fs_info->pinned_radix, |
9f5fae2f CM |
249 | (void **)gang, 0, |
250 | ARRAY_SIZE(gang), | |
251 | CTREE_EXTENT_PENDING_DEL); | |
a28ec197 CM |
252 | if (!ret) |
253 | break; | |
254 | for (i = 0; i < ret; i++) { | |
d5719762 CM |
255 | radix_tree_tag_set(radix, gang[i]->b_blocknr, |
256 | CTREE_EXTENT_PINNED); | |
257 | radix_tree_tag_clear(radix, gang[i]->b_blocknr, | |
9f5fae2f | 258 | CTREE_EXTENT_PENDING_DEL); |
d5719762 CM |
259 | wret = __free_extent(trans, extent_root, |
260 | gang[i]->b_blocknr, 1); | |
e20d96d6 CM |
261 | if (wret) |
262 | err = wret; | |
fec577fb CM |
263 | } |
264 | } | |
e20d96d6 | 265 | return err; |
fec577fb CM |
266 | } |
267 | ||
268 | /* | |
269 | * remove an extent from the root, returns 0 on success | |
270 | */ | |
e089f05c CM |
271 | int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
272 | *root, u64 blocknr, u64 num_blocks, int pin) | |
fec577fb | 273 | { |
9f5fae2f | 274 | struct btrfs_root *extent_root = root->fs_info->extent_root; |
e20d96d6 | 275 | struct buffer_head *t; |
fec577fb CM |
276 | int pending_ret; |
277 | int ret; | |
a28ec197 | 278 | |
fec577fb | 279 | if (root == extent_root) { |
a28ec197 | 280 | t = find_tree_block(root, blocknr); |
e20d96d6 | 281 | pin_down_block(root, blocknr, CTREE_EXTENT_PENDING_DEL); |
fec577fb CM |
282 | return 0; |
283 | } | |
e20d96d6 CM |
284 | if (pin) { |
285 | ret = pin_down_block(root, blocknr, CTREE_EXTENT_PINNED); | |
286 | BUG_ON(ret); | |
287 | } | |
288 | ret = __free_extent(trans, root, blocknr, num_blocks); | |
289 | pending_ret = del_pending_extents(trans, root->fs_info->extent_root); | |
fec577fb CM |
290 | return ret ? ret : pending_ret; |
291 | } | |
292 | ||
293 | /* | |
294 | * walks the btree of allocated extents and find a hole of a given size. | |
295 | * The key ins is changed to record the hole: | |
296 | * ins->objectid == block start | |
62e2749e | 297 | * ins->flags = BTRFS_EXTENT_ITEM_KEY |
fec577fb CM |
298 | * ins->offset == number of blocks |
299 | * Any available blocks before search_start are skipped. | |
300 | */ | |
e089f05c CM |
301 | static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
302 | *orig_root, u64 num_blocks, u64 search_start, u64 | |
303 | search_end, struct btrfs_key *ins) | |
fec577fb | 304 | { |
234b63a0 | 305 | struct btrfs_path path; |
e2fa7227 | 306 | struct btrfs_key key; |
fec577fb CM |
307 | int ret; |
308 | u64 hole_size = 0; | |
309 | int slot = 0; | |
e20d96d6 | 310 | u64 last_block = 0; |
037e6390 | 311 | u64 test_block; |
fec577fb | 312 | int start_found; |
234b63a0 | 313 | struct btrfs_leaf *l; |
9f5fae2f | 314 | struct btrfs_root * root = orig_root->fs_info->extent_root; |
0579da42 | 315 | int total_needed = num_blocks; |
e20d96d6 | 316 | int level; |
fec577fb | 317 | |
e20d96d6 CM |
318 | level = btrfs_header_level(btrfs_buffer_header(root->node)); |
319 | total_needed += (level + 1) * 3; | |
9f5fae2f CM |
320 | if (root->fs_info->last_insert.objectid > search_start) |
321 | search_start = root->fs_info->last_insert.objectid; | |
62e2749e CM |
322 | |
323 | ins->flags = 0; | |
324 | btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY); | |
325 | ||
fec577fb | 326 | check_failed: |
234b63a0 | 327 | btrfs_init_path(&path); |
fec577fb CM |
328 | ins->objectid = search_start; |
329 | ins->offset = 0; | |
fec577fb | 330 | start_found = 0; |
e089f05c | 331 | ret = btrfs_search_slot(trans, root, ins, &path, 0, 0); |
0f70abe2 CM |
332 | if (ret < 0) |
333 | goto error; | |
aa5d6bed | 334 | |
0579da42 CM |
335 | if (path.slots[0] > 0) |
336 | path.slots[0]--; | |
337 | ||
fec577fb | 338 | while (1) { |
e20d96d6 | 339 | l = btrfs_buffer_leaf(path.nodes[0]); |
fec577fb | 340 | slot = path.slots[0]; |
7518a238 | 341 | if (slot >= btrfs_header_nritems(&l->header)) { |
234b63a0 | 342 | ret = btrfs_next_leaf(root, &path); |
fec577fb CM |
343 | if (ret == 0) |
344 | continue; | |
0f70abe2 CM |
345 | if (ret < 0) |
346 | goto error; | |
fec577fb CM |
347 | if (!start_found) { |
348 | ins->objectid = search_start; | |
037e6390 | 349 | ins->offset = (u64)-1; |
fec577fb CM |
350 | start_found = 1; |
351 | goto check_pending; | |
352 | } | |
353 | ins->objectid = last_block > search_start ? | |
354 | last_block : search_start; | |
037e6390 | 355 | ins->offset = (u64)-1; |
fec577fb CM |
356 | goto check_pending; |
357 | } | |
e2fa7227 CM |
358 | btrfs_disk_key_to_cpu(&key, &l->items[slot].key); |
359 | if (key.objectid >= search_start) { | |
fec577fb | 360 | if (start_found) { |
0579da42 CM |
361 | if (last_block < search_start) |
362 | last_block = search_start; | |
e2fa7227 | 363 | hole_size = key.objectid - last_block; |
037e6390 | 364 | if (hole_size > total_needed) { |
fec577fb | 365 | ins->objectid = last_block; |
037e6390 | 366 | ins->offset = hole_size; |
fec577fb CM |
367 | goto check_pending; |
368 | } | |
0579da42 | 369 | } |
fec577fb | 370 | } |
0579da42 | 371 | start_found = 1; |
e2fa7227 | 372 | last_block = key.objectid + key.offset; |
fec577fb CM |
373 | path.slots[0]++; |
374 | } | |
375 | // FIXME -ENOSPC | |
376 | check_pending: | |
377 | /* we have to make sure we didn't find an extent that has already | |
378 | * been allocated by the map tree or the original allocation | |
379 | */ | |
234b63a0 | 380 | btrfs_release_path(root, &path); |
fec577fb | 381 | BUG_ON(ins->objectid < search_start); |
037e6390 CM |
382 | for (test_block = ins->objectid; |
383 | test_block < ins->objectid + total_needed; test_block++) { | |
9f5fae2f CM |
384 | if (radix_tree_lookup(&root->fs_info->pinned_radix, |
385 | test_block)) { | |
037e6390 | 386 | search_start = test_block + 1; |
fec577fb CM |
387 | goto check_failed; |
388 | } | |
389 | } | |
9f5fae2f CM |
390 | BUG_ON(root->fs_info->current_insert.offset); |
391 | root->fs_info->current_insert.offset = total_needed - num_blocks; | |
392 | root->fs_info->current_insert.objectid = ins->objectid + num_blocks; | |
393 | root->fs_info->current_insert.flags = 0; | |
394 | root->fs_info->last_insert.objectid = ins->objectid; | |
037e6390 | 395 | ins->offset = num_blocks; |
fec577fb | 396 | return 0; |
0f70abe2 | 397 | error: |
234b63a0 | 398 | btrfs_release_path(root, &path); |
0f70abe2 | 399 | return ret; |
fec577fb CM |
400 | } |
401 | ||
fec577fb CM |
402 | /* |
403 | * finds a free extent and does all the dirty work required for allocation | |
404 | * returns the key for the extent through ins, and a tree buffer for | |
405 | * the first block of the extent through buf. | |
406 | * | |
407 | * returns 0 if everything worked, non-zero otherwise. | |
408 | */ | |
e089f05c CM |
409 | static int alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root |
410 | *root, u64 num_blocks, u64 search_start, u64 | |
411 | search_end, u64 owner, struct btrfs_key *ins) | |
fec577fb CM |
412 | { |
413 | int ret; | |
414 | int pending_ret; | |
1261ec42 CM |
415 | u64 super_blocks_used; |
416 | struct btrfs_fs_info *info = root->fs_info; | |
417 | struct btrfs_root *extent_root = info->extent_root; | |
234b63a0 | 418 | struct btrfs_extent_item extent_item; |
037e6390 | 419 | |
cf27e1ee CM |
420 | btrfs_set_extent_refs(&extent_item, 1); |
421 | btrfs_set_extent_owner(&extent_item, owner); | |
fec577fb | 422 | |
037e6390 | 423 | if (root == extent_root) { |
9f5fae2f | 424 | BUG_ON(extent_root->fs_info->current_insert.offset == 0); |
037e6390 | 425 | BUG_ON(num_blocks != 1); |
9f5fae2f CM |
426 | BUG_ON(extent_root->fs_info->current_insert.flags == |
427 | extent_root->fs_info->current_insert.offset); | |
037e6390 | 428 | ins->offset = 1; |
9f5fae2f CM |
429 | ins->objectid = extent_root->fs_info->current_insert.objectid + |
430 | extent_root->fs_info->current_insert.flags++; | |
fec577fb CM |
431 | return 0; |
432 | } | |
e089f05c | 433 | ret = find_free_extent(trans, root, num_blocks, search_start, |
037e6390 CM |
434 | search_end, ins); |
435 | if (ret) | |
436 | return ret; | |
fec577fb | 437 | |
1261ec42 CM |
438 | super_blocks_used = btrfs_super_blocks_used(info->disk_super); |
439 | btrfs_set_super_blocks_used(info->disk_super, super_blocks_used + | |
440 | num_blocks); | |
e089f05c CM |
441 | ret = btrfs_insert_item(trans, extent_root, ins, &extent_item, |
442 | sizeof(extent_item)); | |
037e6390 | 443 | |
e089f05c | 444 | finish_current_insert(trans, extent_root); |
e20d96d6 | 445 | pending_ret = del_pending_extents(trans, extent_root); |
037e6390 CM |
446 | if (ret) |
447 | return ret; | |
448 | if (pending_ret) | |
449 | return pending_ret; | |
450 | return 0; | |
fec577fb CM |
451 | } |
452 | ||
453 | /* | |
454 | * helper function to allocate a block for a given tree | |
455 | * returns the tree buffer or NULL. | |
456 | */ | |
e20d96d6 | 457 | struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans, |
e089f05c | 458 | struct btrfs_root *root) |
fec577fb | 459 | { |
e2fa7227 | 460 | struct btrfs_key ins; |
fec577fb | 461 | int ret; |
e20d96d6 | 462 | struct buffer_head *buf; |
fec577fb | 463 | |
e089f05c | 464 | ret = alloc_extent(trans, root, 1, 0, (unsigned long)-1, |
e20d96d6 | 465 | btrfs_header_parentid(btrfs_buffer_header(root->node)), &ins); |
fec577fb CM |
466 | if (ret) { |
467 | BUG(); | |
468 | return NULL; | |
469 | } | |
037e6390 | 470 | buf = find_tree_block(root, ins.objectid); |
df2ce34c | 471 | set_buffer_uptodate(buf); |
fec577fb CM |
472 | return buf; |
473 | } | |
a28ec197 | 474 | |
9aca1d51 CM |
475 | /* |
476 | * helper function for drop_snapshot, this walks down the tree dropping ref | |
477 | * counts as it goes. | |
478 | */ | |
e089f05c CM |
479 | static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root |
480 | *root, struct btrfs_path *path, int *level) | |
20524f02 | 481 | { |
e20d96d6 CM |
482 | struct buffer_head *next; |
483 | struct buffer_head *cur; | |
20524f02 CM |
484 | u64 blocknr; |
485 | int ret; | |
486 | u32 refs; | |
487 | ||
e20d96d6 | 488 | ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr, |
e089f05c | 489 | &refs); |
20524f02 CM |
490 | BUG_ON(ret); |
491 | if (refs > 1) | |
492 | goto out; | |
9aca1d51 CM |
493 | /* |
494 | * walk down to the last node level and free all the leaves | |
495 | */ | |
20524f02 CM |
496 | while(*level > 0) { |
497 | cur = path->nodes[*level]; | |
7518a238 | 498 | if (path->slots[*level] >= |
e20d96d6 | 499 | btrfs_header_nritems(btrfs_buffer_header(cur))) |
20524f02 | 500 | break; |
e20d96d6 CM |
501 | blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur), |
502 | path->slots[*level]); | |
e089f05c | 503 | ret = lookup_block_ref(trans, root, blocknr, &refs); |
20524f02 CM |
504 | if (refs != 1 || *level == 1) { |
505 | path->slots[*level]++; | |
e089f05c | 506 | ret = btrfs_free_extent(trans, root, blocknr, 1, 1); |
20524f02 CM |
507 | BUG_ON(ret); |
508 | continue; | |
509 | } | |
510 | BUG_ON(ret); | |
511 | next = read_tree_block(root, blocknr); | |
83e15a28 | 512 | if (path->nodes[*level-1]) |
234b63a0 | 513 | btrfs_block_release(root, path->nodes[*level-1]); |
20524f02 | 514 | path->nodes[*level-1] = next; |
e20d96d6 | 515 | *level = btrfs_header_level(btrfs_buffer_header(next)); |
20524f02 CM |
516 | path->slots[*level] = 0; |
517 | } | |
518 | out: | |
e20d96d6 CM |
519 | ret = btrfs_free_extent(trans, root, path->nodes[*level]->b_blocknr, |
520 | 1, 1); | |
234b63a0 | 521 | btrfs_block_release(root, path->nodes[*level]); |
20524f02 CM |
522 | path->nodes[*level] = NULL; |
523 | *level += 1; | |
524 | BUG_ON(ret); | |
525 | return 0; | |
526 | } | |
527 | ||
9aca1d51 CM |
528 | /* |
529 | * helper for dropping snapshots. This walks back up the tree in the path | |
530 | * to find the first node higher up where we haven't yet gone through | |
531 | * all the slots | |
532 | */ | |
e089f05c CM |
533 | static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root |
534 | *root, struct btrfs_path *path, int *level) | |
20524f02 CM |
535 | { |
536 | int i; | |
537 | int slot; | |
538 | int ret; | |
234b63a0 | 539 | for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) { |
20524f02 | 540 | slot = path->slots[i]; |
e20d96d6 CM |
541 | if (slot < btrfs_header_nritems( |
542 | btrfs_buffer_header(path->nodes[i])) - 1) { | |
20524f02 CM |
543 | path->slots[i]++; |
544 | *level = i; | |
545 | return 0; | |
546 | } else { | |
e089f05c | 547 | ret = btrfs_free_extent(trans, root, |
e20d96d6 | 548 | path->nodes[*level]->b_blocknr, |
e089f05c | 549 | 1, 1); |
234b63a0 | 550 | btrfs_block_release(root, path->nodes[*level]); |
83e15a28 | 551 | path->nodes[*level] = NULL; |
20524f02 CM |
552 | *level = i + 1; |
553 | BUG_ON(ret); | |
554 | } | |
555 | } | |
556 | return 1; | |
557 | } | |
558 | ||
9aca1d51 CM |
559 | /* |
560 | * drop the reference count on the tree rooted at 'snap'. This traverses | |
561 | * the tree freeing any blocks that have a ref count of zero after being | |
562 | * decremented. | |
563 | */ | |
e089f05c | 564 | int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root |
e20d96d6 | 565 | *root, struct buffer_head *snap) |
20524f02 | 566 | { |
3768f368 | 567 | int ret = 0; |
9aca1d51 | 568 | int wret; |
20524f02 | 569 | int level; |
234b63a0 | 570 | struct btrfs_path path; |
20524f02 CM |
571 | int i; |
572 | int orig_level; | |
573 | ||
234b63a0 | 574 | btrfs_init_path(&path); |
20524f02 | 575 | |
e20d96d6 | 576 | level = btrfs_header_level(btrfs_buffer_header(snap)); |
20524f02 CM |
577 | orig_level = level; |
578 | path.nodes[level] = snap; | |
579 | path.slots[level] = 0; | |
580 | while(1) { | |
e089f05c | 581 | wret = walk_down_tree(trans, root, &path, &level); |
9aca1d51 | 582 | if (wret > 0) |
20524f02 | 583 | break; |
9aca1d51 CM |
584 | if (wret < 0) |
585 | ret = wret; | |
586 | ||
e089f05c | 587 | wret = walk_up_tree(trans, root, &path, &level); |
9aca1d51 | 588 | if (wret > 0) |
20524f02 | 589 | break; |
9aca1d51 CM |
590 | if (wret < 0) |
591 | ret = wret; | |
20524f02 | 592 | } |
83e15a28 CM |
593 | for (i = 0; i <= orig_level; i++) { |
594 | if (path.nodes[i]) { | |
234b63a0 | 595 | btrfs_block_release(root, path.nodes[i]); |
83e15a28 | 596 | } |
20524f02 | 597 | } |
9aca1d51 | 598 | return ret; |
20524f02 | 599 | } |