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
->fs_info
->extent_root
, 0, 0, (u64
)-1,
40 btrfs_init_path(&path
);
41 key
.objectid
= blocknr
;
43 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
45 ret
= btrfs_search_slot(trans
, root
->fs_info
->extent_root
, &key
, &path
,
50 l
= &path
.nodes
[0]->leaf
;
51 item
= btrfs_item_ptr(l
, path
.slots
[0], struct btrfs_extent_item
);
52 refs
= btrfs_extent_refs(item
);
53 btrfs_set_extent_refs(item
, refs
+ 1);
55 BUG_ON(list_empty(&path
.nodes
[0]->dirty
));
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
);
62 static int lookup_block_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
63 *root
, u64 blocknr
, u32
*refs
)
65 struct btrfs_path path
;
69 struct btrfs_extent_item
*item
;
70 btrfs_init_path(&path
);
71 key
.objectid
= blocknr
;
74 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
75 ret
= btrfs_search_slot(trans
, root
->fs_info
->extent_root
, &key
, &path
,
79 l
= &path
.nodes
[0]->leaf
;
80 item
= btrfs_item_ptr(l
, path
.slots
[0], struct btrfs_extent_item
);
81 *refs
= btrfs_extent_refs(item
);
82 btrfs_release_path(root
->fs_info
->extent_root
, &path
);
86 int btrfs_inc_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
87 struct btrfs_buffer
*buf
)
94 if (btrfs_is_leaf(&buf
->node
))
97 for (i
= 0; i
< btrfs_header_nritems(&buf
->node
.header
); i
++) {
98 blocknr
= btrfs_node_blockptr(&buf
->node
, i
);
99 inc_block_ref(trans
, root
, blocknr
);
104 int btrfs_finish_extent_commit(struct btrfs_trans_handle
*trans
, struct
107 unsigned long gang
[8];
113 ret
= radix_tree_gang_lookup(&root
->fs_info
->pinned_radix
,
120 for (i
= 0; i
< ret
; i
++) {
121 radix_tree_delete(&root
->fs_info
->pinned_radix
,
125 root
->fs_info
->last_insert
.objectid
= first
;
126 root
->fs_info
->last_insert
.offset
= 0;
130 static int finish_current_insert(struct btrfs_trans_handle
*trans
, struct
131 btrfs_root
*extent_root
)
133 struct btrfs_key ins
;
134 struct btrfs_extent_item extent_item
;
138 btrfs_set_extent_refs(&extent_item
, 1);
139 btrfs_set_extent_owner(&extent_item
,
140 btrfs_header_parentid(&extent_root
->node
->node
.header
));
143 btrfs_set_key_type(&ins
, BTRFS_EXTENT_ITEM_KEY
);
145 for (i
= 0; i
< extent_root
->fs_info
->current_insert
.flags
; i
++) {
146 ins
.objectid
= extent_root
->fs_info
->current_insert
.objectid
+
148 ret
= btrfs_insert_item(trans
, extent_root
, &ins
, &extent_item
,
149 sizeof(extent_item
));
152 extent_root
->fs_info
->current_insert
.offset
= 0;
157 * remove an extent from the root, returns 0 on success
159 static int __free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
160 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
162 struct btrfs_path path
;
163 struct btrfs_key key
;
164 struct btrfs_root
*extent_root
= root
->fs_info
->extent_root
;
166 struct btrfs_extent_item
*ei
;
167 struct btrfs_key ins
;
170 BUG_ON(pin
&& num_blocks
!= 1);
171 key
.objectid
= blocknr
;
173 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
174 key
.offset
= num_blocks
;
176 find_free_extent(trans
, root
, 0, 0, (u64
)-1, &ins
);
177 btrfs_init_path(&path
);
178 ret
= btrfs_search_slot(trans
, extent_root
, &key
, &path
, -1, 1);
180 printf("failed to find %Lu\n", key
.objectid
);
181 btrfs_print_tree(extent_root
, extent_root
->node
);
182 printf("failed to find %Lu\n", key
.objectid
);
185 ei
= btrfs_item_ptr(&path
.nodes
[0]->leaf
, path
.slots
[0],
186 struct btrfs_extent_item
);
187 BUG_ON(ei
->refs
== 0);
188 refs
= btrfs_extent_refs(ei
) - 1;
189 btrfs_set_extent_refs(ei
, refs
);
193 radix_tree_preload(GFP_KERNEL
);
194 err
= radix_tree_insert(
195 &extent_root
->fs_info
->pinned_radix
,
196 blocknr
, (void *)blocknr
);
198 radix_tree_preload_end();
200 ret
= btrfs_del_item(trans
, extent_root
, &path
);
201 if (!pin
&& extent_root
->fs_info
->last_insert
.objectid
>
203 extent_root
->fs_info
->last_insert
.objectid
= blocknr
;
207 btrfs_release_path(extent_root
, &path
);
208 finish_current_insert(trans
, extent_root
);
213 * find all the blocks marked as pending in the radix tree and remove
214 * them from the extent map
216 static int del_pending_extents(struct btrfs_trans_handle
*trans
, struct
217 btrfs_root
*extent_root
)
220 struct btrfs_buffer
*gang
[4];
224 ret
= radix_tree_gang_lookup_tag(
225 &extent_root
->fs_info
->cache_radix
,
228 CTREE_EXTENT_PENDING_DEL
);
231 for (i
= 0; i
< ret
; i
++) {
232 ret
= __free_extent(trans
, extent_root
,
233 gang
[i
]->blocknr
, 1, 1);
234 radix_tree_tag_clear(&extent_root
->fs_info
->cache_radix
,
236 CTREE_EXTENT_PENDING_DEL
);
237 btrfs_block_release(extent_root
, gang
[i
]);
243 static int run_pending(struct btrfs_trans_handle
*trans
, struct btrfs_root
246 while(radix_tree_tagged(&extent_root
->fs_info
->cache_radix
,
247 CTREE_EXTENT_PENDING_DEL
))
248 del_pending_extents(trans
, extent_root
);
254 * remove an extent from the root, returns 0 on success
256 int btrfs_free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
257 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
259 struct btrfs_root
*extent_root
= root
->fs_info
->extent_root
;
260 struct btrfs_buffer
*t
;
264 if (root
== extent_root
) {
265 t
= find_tree_block(root
, blocknr
);
266 radix_tree_tag_set(&root
->fs_info
->cache_radix
, blocknr
,
267 CTREE_EXTENT_PENDING_DEL
);
270 ret
= __free_extent(trans
, root
, blocknr
, num_blocks
, pin
);
271 pending_ret
= run_pending(trans
, root
->fs_info
->extent_root
);
272 return ret
? ret
: pending_ret
;
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
279 * ins->flags = BTRFS_EXTENT_ITEM_KEY
280 * ins->offset == number of blocks
281 * Any available blocks before search_start are skipped.
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
)
287 struct btrfs_path path
;
288 struct btrfs_key key
;
295 struct btrfs_leaf
*l
;
296 struct btrfs_root
* root
= orig_root
->fs_info
->extent_root
;
297 int total_needed
= num_blocks
;
299 total_needed
+= (btrfs_header_level(&root
->node
->node
.header
) + 1) * 3;
300 if (root
->fs_info
->last_insert
.objectid
> search_start
)
301 search_start
= root
->fs_info
->last_insert
.objectid
;
304 btrfs_set_key_type(ins
, BTRFS_EXTENT_ITEM_KEY
);
307 btrfs_init_path(&path
);
308 ins
->objectid
= search_start
;
311 ret
= btrfs_search_slot(trans
, root
, ins
, &path
, 0, 0);
315 if (path
.slots
[0] > 0)
319 l
= &path
.nodes
[0]->leaf
;
320 slot
= path
.slots
[0];
321 if (slot
>= btrfs_header_nritems(&l
->header
)) {
322 ret
= btrfs_next_leaf(root
, &path
);
328 ins
->objectid
= search_start
;
329 ins
->offset
= (u64
)-1;
333 ins
->objectid
= last_block
> search_start
?
334 last_block
: search_start
;
335 ins
->offset
= (u64
)-1;
338 btrfs_disk_key_to_cpu(&key
, &l
->items
[slot
].key
);
339 if (key
.objectid
>= search_start
) {
341 if (last_block
< search_start
)
342 last_block
= search_start
;
343 hole_size
= key
.objectid
- last_block
;
344 if (hole_size
> total_needed
) {
345 ins
->objectid
= last_block
;
346 ins
->offset
= hole_size
;
352 last_block
= key
.objectid
+ key
.offset
;
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
360 btrfs_release_path(root
, &path
);
361 BUG_ON(ins
->objectid
< search_start
);
362 for (test_block
= ins
->objectid
;
363 test_block
< ins
->objectid
+ total_needed
; test_block
++) {
364 if (radix_tree_lookup(&root
->fs_info
->pinned_radix
,
366 search_start
= test_block
+ 1;
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
;
375 ins
->offset
= num_blocks
;
378 btrfs_release_path(root
, &path
);
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.
387 * returns 0 if everything worked, non-zero otherwise.
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
)
395 struct btrfs_root
*extent_root
= root
->fs_info
->extent_root
;
396 struct btrfs_extent_item extent_item
;
398 btrfs_set_extent_refs(&extent_item
, 1);
399 btrfs_set_extent_owner(&extent_item
, owner
);
401 if (root
== extent_root
) {
402 BUG_ON(extent_root
->fs_info
->current_insert
.offset
== 0);
403 BUG_ON(num_blocks
!= 1);
404 BUG_ON(extent_root
->fs_info
->current_insert
.flags
==
405 extent_root
->fs_info
->current_insert
.offset
);
407 ins
->objectid
= extent_root
->fs_info
->current_insert
.objectid
+
408 extent_root
->fs_info
->current_insert
.flags
++;
411 ret
= find_free_extent(trans
, root
, num_blocks
, search_start
,
416 ret
= btrfs_insert_item(trans
, extent_root
, ins
, &extent_item
,
417 sizeof(extent_item
));
419 finish_current_insert(trans
, extent_root
);
420 pending_ret
= run_pending(trans
, extent_root
);
429 * helper function to allocate a block for a given tree
430 * returns the tree buffer or NULL.
432 struct btrfs_buffer
*btrfs_alloc_free_block(struct btrfs_trans_handle
*trans
,
433 struct btrfs_root
*root
)
435 struct btrfs_key ins
;
437 struct btrfs_buffer
*buf
;
439 ret
= alloc_extent(trans
, root
, 1, 0, (unsigned long)-1,
440 btrfs_header_parentid(&root
->node
->node
.header
),
446 buf
= find_tree_block(root
, ins
.objectid
);
447 dirty_tree_block(trans
, root
, buf
);
452 * helper function for drop_snapshot, this walks down the tree dropping ref
455 static int walk_down_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
456 *root
, struct btrfs_path
*path
, int *level
)
458 struct btrfs_buffer
*next
;
459 struct btrfs_buffer
*cur
;
464 ret
= lookup_block_ref(trans
, root
, path
->nodes
[*level
]->blocknr
,
470 * walk down to the last node level and free all the leaves
473 cur
= path
->nodes
[*level
];
474 if (path
->slots
[*level
] >=
475 btrfs_header_nritems(&cur
->node
.header
))
477 blocknr
= btrfs_node_blockptr(&cur
->node
, path
->slots
[*level
]);
478 ret
= lookup_block_ref(trans
, root
, blocknr
, &refs
);
479 if (refs
!= 1 || *level
== 1) {
480 path
->slots
[*level
]++;
481 ret
= btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
486 next
= read_tree_block(root
, blocknr
);
487 if (path
->nodes
[*level
-1])
488 btrfs_block_release(root
, path
->nodes
[*level
-1]);
489 path
->nodes
[*level
-1] = next
;
490 *level
= btrfs_header_level(&next
->node
.header
);
491 path
->slots
[*level
] = 0;
494 ret
= btrfs_free_extent(trans
, root
, path
->nodes
[*level
]->blocknr
, 1,
496 btrfs_block_release(root
, path
->nodes
[*level
]);
497 path
->nodes
[*level
] = NULL
;
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
508 static int walk_up_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
509 *root
, struct btrfs_path
*path
, int *level
)
514 for(i
= *level
; i
< BTRFS_MAX_LEVEL
- 1 && path
->nodes
[i
]; i
++) {
515 slot
= path
->slots
[i
];
517 btrfs_header_nritems(&path
->nodes
[i
]->node
.header
)- 1) {
522 ret
= btrfs_free_extent(trans
, root
,
523 path
->nodes
[*level
]->blocknr
,
525 btrfs_block_release(root
, path
->nodes
[*level
]);
526 path
->nodes
[*level
] = NULL
;
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
539 int btrfs_drop_snapshot(struct btrfs_trans_handle
*trans
, struct btrfs_root
540 *root
, struct btrfs_buffer
*snap
)
545 struct btrfs_path path
;
549 btrfs_init_path(&path
);
551 level
= btrfs_header_level(&snap
->node
.header
);
553 path
.nodes
[level
] = snap
;
554 path
.slots
[level
] = 0;
556 wret
= walk_down_tree(trans
, root
, &path
, &level
);
562 wret
= walk_up_tree(trans
, root
, &path
, &level
);
568 for (i
= 0; i
<= orig_level
; i
++) {
570 btrfs_block_release(root
, path
.nodes
[i
]);