3 #include "kerncompat.h"
4 #include "radix-tree.h"
7 #include "print-tree.h"
8 #include "transaction.h"
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
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
25 #define CTREE_EXTENT_PENDING_DEL 0
27 static int inc_block_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
30 struct btrfs_path path
;
34 struct btrfs_extent_item
*item
;
38 find_free_extent(trans
, root
->extent_root
, 0, 0, (u64
)-1, &ins
);
39 btrfs_init_path(&path
);
40 key
.objectid
= blocknr
;
42 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
44 ret
= btrfs_search_slot(trans
, root
->extent_root
, &key
, &path
, 0, 1);
48 l
= &path
.nodes
[0]->leaf
;
49 item
= btrfs_item_ptr(l
, path
.slots
[0], struct btrfs_extent_item
);
50 refs
= btrfs_extent_refs(item
);
51 btrfs_set_extent_refs(item
, refs
+ 1);
53 BUG_ON(list_empty(&path
.nodes
[0]->dirty
));
54 btrfs_release_path(root
->extent_root
, &path
);
55 finish_current_insert(trans
, root
->extent_root
);
56 run_pending(trans
, root
->extent_root
);
60 static int lookup_block_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
61 *root
, u64 blocknr
, u32
*refs
)
63 struct btrfs_path path
;
67 struct btrfs_extent_item
*item
;
68 btrfs_init_path(&path
);
69 key
.objectid
= blocknr
;
72 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
73 ret
= btrfs_search_slot(trans
, root
->extent_root
, &key
, &path
, 0, 0);
76 l
= &path
.nodes
[0]->leaf
;
77 item
= btrfs_item_ptr(l
, path
.slots
[0], struct btrfs_extent_item
);
78 *refs
= btrfs_extent_refs(item
);
79 btrfs_release_path(root
->extent_root
, &path
);
83 int btrfs_inc_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
84 struct btrfs_buffer
*buf
)
91 if (btrfs_is_leaf(&buf
->node
))
94 for (i
= 0; i
< btrfs_header_nritems(&buf
->node
.header
); i
++) {
95 blocknr
= btrfs_node_blockptr(&buf
->node
, i
);
96 inc_block_ref(trans
, root
, blocknr
);
101 int btrfs_finish_extent_commit(struct btrfs_trans_handle
*trans
, struct
104 unsigned long gang
[8];
110 ret
= radix_tree_gang_lookup(&root
->pinned_radix
,
117 for (i
= 0; i
< ret
; i
++) {
118 radix_tree_delete(&root
->pinned_radix
, gang
[i
]);
121 root
->last_insert
.objectid
= first
;
122 root
->last_insert
.offset
= 0;
126 static int finish_current_insert(struct btrfs_trans_handle
*trans
, struct
127 btrfs_root
*extent_root
)
129 struct btrfs_key ins
;
130 struct btrfs_extent_item extent_item
;
134 btrfs_set_extent_refs(&extent_item
, 1);
135 btrfs_set_extent_owner(&extent_item
,
136 btrfs_header_parentid(&extent_root
->node
->node
.header
));
139 btrfs_set_key_type(&ins
, BTRFS_EXTENT_ITEM_KEY
);
141 for (i
= 0; i
< extent_root
->current_insert
.flags
; i
++) {
142 ins
.objectid
= extent_root
->current_insert
.objectid
+ i
;
143 ret
= btrfs_insert_item(trans
, extent_root
, &ins
, &extent_item
,
144 sizeof(extent_item
));
147 extent_root
->current_insert
.offset
= 0;
152 * remove an extent from the root, returns 0 on success
154 static int __free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
155 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
157 struct btrfs_path path
;
158 struct btrfs_key key
;
159 struct btrfs_root
*extent_root
= root
->extent_root
;
161 struct btrfs_extent_item
*ei
;
162 struct btrfs_key ins
;
165 BUG_ON(pin
&& num_blocks
!= 1);
166 key
.objectid
= blocknr
;
168 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
169 key
.offset
= num_blocks
;
171 find_free_extent(trans
, root
, 0, 0, (u64
)-1, &ins
);
172 btrfs_init_path(&path
);
173 ret
= btrfs_search_slot(trans
, extent_root
, &key
, &path
, -1, 1);
175 printf("failed to find %Lu\n", key
.objectid
);
176 btrfs_print_tree(extent_root
, extent_root
->node
);
177 printf("failed to find %Lu\n", key
.objectid
);
180 ei
= btrfs_item_ptr(&path
.nodes
[0]->leaf
, path
.slots
[0],
181 struct btrfs_extent_item
);
182 BUG_ON(ei
->refs
== 0);
183 refs
= btrfs_extent_refs(ei
) - 1;
184 btrfs_set_extent_refs(ei
, refs
);
188 radix_tree_preload(GFP_KERNEL
);
189 err
= radix_tree_insert(&extent_root
->pinned_radix
,
190 blocknr
, (void *)blocknr
);
192 radix_tree_preload_end();
194 ret
= btrfs_del_item(trans
, extent_root
, &path
);
195 if (!pin
&& extent_root
->last_insert
.objectid
> blocknr
)
196 extent_root
->last_insert
.objectid
= blocknr
;
200 btrfs_release_path(extent_root
, &path
);
201 finish_current_insert(trans
, extent_root
);
206 * find all the blocks marked as pending in the radix tree and remove
207 * them from the extent map
209 static int del_pending_extents(struct btrfs_trans_handle
*trans
, struct
210 btrfs_root
*extent_root
)
213 struct btrfs_buffer
*gang
[4];
217 ret
= radix_tree_gang_lookup_tag(&extent_root
->cache_radix
,
220 CTREE_EXTENT_PENDING_DEL
);
223 for (i
= 0; i
< ret
; i
++) {
224 ret
= __free_extent(trans
, extent_root
,
225 gang
[i
]->blocknr
, 1, 1);
226 radix_tree_tag_clear(&extent_root
->cache_radix
,
228 CTREE_EXTENT_PENDING_DEL
);
229 btrfs_block_release(extent_root
, gang
[i
]);
235 static int run_pending(struct btrfs_trans_handle
*trans
, struct btrfs_root
238 while(radix_tree_tagged(&extent_root
->cache_radix
,
239 CTREE_EXTENT_PENDING_DEL
))
240 del_pending_extents(trans
, extent_root
);
246 * remove an extent from the root, returns 0 on success
248 int btrfs_free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
249 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
251 struct btrfs_root
*extent_root
= root
->extent_root
;
252 struct btrfs_buffer
*t
;
256 if (root
== extent_root
) {
257 t
= find_tree_block(root
, blocknr
);
258 radix_tree_tag_set(&root
->cache_radix
, blocknr
,
259 CTREE_EXTENT_PENDING_DEL
);
262 ret
= __free_extent(trans
, root
, blocknr
, num_blocks
, pin
);
263 pending_ret
= run_pending(trans
, root
->extent_root
);
264 return ret
? ret
: pending_ret
;
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
271 * ins->flags = BTRFS_EXTENT_ITEM_KEY
272 * ins->offset == number of blocks
273 * Any available blocks before search_start are skipped.
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
)
279 struct btrfs_path path
;
280 struct btrfs_key key
;
287 struct btrfs_leaf
*l
;
288 struct btrfs_root
* root
= orig_root
->extent_root
;
289 int total_needed
= num_blocks
;
291 total_needed
+= (btrfs_header_level(&root
->node
->node
.header
) + 1) * 3;
292 if (root
->last_insert
.objectid
> search_start
)
293 search_start
= root
->last_insert
.objectid
;
296 btrfs_set_key_type(ins
, BTRFS_EXTENT_ITEM_KEY
);
299 btrfs_init_path(&path
);
300 ins
->objectid
= search_start
;
303 ret
= btrfs_search_slot(trans
, root
, ins
, &path
, 0, 0);
307 if (path
.slots
[0] > 0)
311 l
= &path
.nodes
[0]->leaf
;
312 slot
= path
.slots
[0];
313 if (slot
>= btrfs_header_nritems(&l
->header
)) {
314 ret
= btrfs_next_leaf(root
, &path
);
320 ins
->objectid
= search_start
;
321 ins
->offset
= (u64
)-1;
325 ins
->objectid
= last_block
> search_start
?
326 last_block
: search_start
;
327 ins
->offset
= (u64
)-1;
330 btrfs_disk_key_to_cpu(&key
, &l
->items
[slot
].key
);
331 if (key
.objectid
>= search_start
) {
333 if (last_block
< search_start
)
334 last_block
= search_start
;
335 hole_size
= key
.objectid
- last_block
;
336 if (hole_size
> total_needed
) {
337 ins
->objectid
= last_block
;
338 ins
->offset
= hole_size
;
344 last_block
= key
.objectid
+ key
.offset
;
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
352 btrfs_release_path(root
, &path
);
353 BUG_ON(ins
->objectid
< search_start
);
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;
361 BUG_ON(root
->current_insert
.offset
);
362 root
->current_insert
.offset
= total_needed
- num_blocks
;
363 root
->current_insert
.objectid
= ins
->objectid
+ num_blocks
;
364 root
->current_insert
.flags
= 0;
365 root
->last_insert
.objectid
= ins
->objectid
;
366 ins
->offset
= num_blocks
;
369 btrfs_release_path(root
, &path
);
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.
378 * returns 0 if everything worked, non-zero otherwise.
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
)
386 struct btrfs_root
*extent_root
= root
->extent_root
;
387 struct btrfs_extent_item extent_item
;
389 btrfs_set_extent_refs(&extent_item
, 1);
390 btrfs_set_extent_owner(&extent_item
, owner
);
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
);
398 ins
->objectid
= extent_root
->current_insert
.objectid
+
399 extent_root
->current_insert
.flags
++;
402 ret
= find_free_extent(trans
, root
, num_blocks
, search_start
,
407 ret
= btrfs_insert_item(trans
, extent_root
, ins
, &extent_item
,
408 sizeof(extent_item
));
410 finish_current_insert(trans
, extent_root
);
411 pending_ret
= run_pending(trans
, extent_root
);
420 * helper function to allocate a block for a given tree
421 * returns the tree buffer or NULL.
423 struct btrfs_buffer
*btrfs_alloc_free_block(struct btrfs_trans_handle
*trans
,
424 struct btrfs_root
*root
)
426 struct btrfs_key ins
;
428 struct btrfs_buffer
*buf
;
430 ret
= alloc_extent(trans
, root
, 1, 0, (unsigned long)-1,
431 btrfs_header_parentid(&root
->node
->node
.header
),
437 buf
= find_tree_block(root
, ins
.objectid
);
438 dirty_tree_block(trans
, root
, buf
);
443 * helper function for drop_snapshot, this walks down the tree dropping ref
446 static int walk_down_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
447 *root
, struct btrfs_path
*path
, int *level
)
449 struct btrfs_buffer
*next
;
450 struct btrfs_buffer
*cur
;
455 ret
= lookup_block_ref(trans
, root
, path
->nodes
[*level
]->blocknr
,
461 * walk down to the last node level and free all the leaves
464 cur
= path
->nodes
[*level
];
465 if (path
->slots
[*level
] >=
466 btrfs_header_nritems(&cur
->node
.header
))
468 blocknr
= btrfs_node_blockptr(&cur
->node
, path
->slots
[*level
]);
469 ret
= lookup_block_ref(trans
, root
, blocknr
, &refs
);
470 if (refs
!= 1 || *level
== 1) {
471 path
->slots
[*level
]++;
472 ret
= btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
477 next
= read_tree_block(root
, blocknr
);
478 if (path
->nodes
[*level
-1])
479 btrfs_block_release(root
, path
->nodes
[*level
-1]);
480 path
->nodes
[*level
-1] = next
;
481 *level
= btrfs_header_level(&next
->node
.header
);
482 path
->slots
[*level
] = 0;
485 ret
= btrfs_free_extent(trans
, root
, path
->nodes
[*level
]->blocknr
, 1,
487 btrfs_block_release(root
, path
->nodes
[*level
]);
488 path
->nodes
[*level
] = NULL
;
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
499 static int walk_up_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
500 *root
, struct btrfs_path
*path
, int *level
)
505 for(i
= *level
; i
< BTRFS_MAX_LEVEL
- 1 && path
->nodes
[i
]; i
++) {
506 slot
= path
->slots
[i
];
508 btrfs_header_nritems(&path
->nodes
[i
]->node
.header
)- 1) {
513 ret
= btrfs_free_extent(trans
, root
,
514 path
->nodes
[*level
]->blocknr
,
516 btrfs_block_release(root
, path
->nodes
[*level
]);
517 path
->nodes
[*level
] = NULL
;
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
530 int btrfs_drop_snapshot(struct btrfs_trans_handle
*trans
, struct btrfs_root
531 *root
, struct btrfs_buffer
*snap
)
536 struct btrfs_path path
;
540 btrfs_init_path(&path
);
542 level
= btrfs_header_level(&snap
->node
.header
);
544 path
.nodes
[level
] = snap
;
545 path
.slots
[level
] = 0;
547 wret
= walk_down_tree(trans
, root
, &path
, &level
);
553 wret
= walk_up_tree(trans
, root
, &path
, &level
);
559 for (i
= 0; i
<= orig_level
; i
++) {
561 btrfs_block_release(root
, path
.nodes
[i
]);