1 #include <linux/module.h>
2 #include <linux/radix-tree.h>
5 #include "print-tree.h"
6 #include "transaction.h"
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
);
13 static int del_pending_extents(struct btrfs_trans_handle
*trans
, struct
14 btrfs_root
*extent_root
);
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
22 #define CTREE_EXTENT_PENDING_DEL 0
23 #define CTREE_EXTENT_PINNED 1
25 static int inc_block_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
28 struct btrfs_path path
;
32 struct btrfs_extent_item
*item
;
36 find_free_extent(trans
, root
->fs_info
->extent_root
, 0, 0, (u64
)-1,
38 btrfs_init_path(&path
);
39 key
.objectid
= blocknr
;
41 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
43 ret
= btrfs_search_slot(trans
, root
->fs_info
->extent_root
, &key
, &path
,
48 l
= btrfs_buffer_leaf(path
.nodes
[0]);
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);
52 mark_buffer_dirty(path
.nodes
[0]);
54 btrfs_release_path(root
->fs_info
->extent_root
, &path
);
55 finish_current_insert(trans
, root
->fs_info
->extent_root
);
56 del_pending_extents(trans
, root
->fs_info
->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
->fs_info
->extent_root
, &key
, &path
,
77 l
= btrfs_buffer_leaf(path
.nodes
[0]);
78 item
= btrfs_item_ptr(l
, path
.slots
[0], struct btrfs_extent_item
);
79 *refs
= btrfs_extent_refs(item
);
80 btrfs_release_path(root
->fs_info
->extent_root
, &path
);
84 int btrfs_inc_ref(struct btrfs_trans_handle
*trans
, struct btrfs_root
*root
,
85 struct buffer_head
*buf
)
88 struct btrfs_node
*buf_node
;
93 buf_node
= btrfs_buffer_node(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 struct buffer_head
*gang
[8];
113 ret
= radix_tree_gang_lookup_tag(&root
->fs_info
->pinned_radix
,
116 CTREE_EXTENT_PINNED
);
120 first
= gang
[0]->b_blocknr
;
121 for (i
= 0; i
< ret
; i
++) {
122 radix_tree_delete(&root
->fs_info
->pinned_radix
,
127 if (root
->fs_info
->last_insert
.objectid
> first
)
128 root
->fs_info
->last_insert
.objectid
= first
;
129 root
->fs_info
->last_insert
.offset
= 0;
133 static int finish_current_insert(struct btrfs_trans_handle
*trans
, struct
134 btrfs_root
*extent_root
)
136 struct btrfs_key ins
;
137 struct btrfs_extent_item extent_item
;
140 u64 super_blocks_used
;
141 struct btrfs_fs_info
*info
= extent_root
->fs_info
;
143 btrfs_set_extent_refs(&extent_item
, 1);
144 btrfs_set_extent_owner(&extent_item
,
145 btrfs_header_parentid(btrfs_buffer_header(extent_root
->node
)));
148 btrfs_set_key_type(&ins
, BTRFS_EXTENT_ITEM_KEY
);
150 for (i
= 0; i
< extent_root
->fs_info
->current_insert
.flags
; i
++) {
151 ins
.objectid
= extent_root
->fs_info
->current_insert
.objectid
+
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);
156 ret
= btrfs_insert_item(trans
, extent_root
, &ins
, &extent_item
,
157 sizeof(extent_item
));
160 extent_root
->fs_info
->current_insert
.offset
= 0;
164 static int pin_down_block(struct btrfs_root
*root
, u64 blocknr
, int tag
)
167 struct buffer_head
*bh
= sb_getblk(root
->fs_info
->sb
, blocknr
);
169 err
= radix_tree_insert(&root
->fs_info
->pinned_radix
,
174 radix_tree_tag_set(&root
->fs_info
->pinned_radix
, blocknr
,
180 * remove an extent from the root, returns 0 on success
182 static int __free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
183 *root
, u64 blocknr
, u64 num_blocks
)
185 struct btrfs_path path
;
186 struct btrfs_key key
;
187 struct btrfs_fs_info
*info
= root
->fs_info
;
188 struct btrfs_root
*extent_root
= info
->extent_root
;
190 struct btrfs_extent_item
*ei
;
191 struct btrfs_key ins
;
194 key
.objectid
= blocknr
;
196 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
197 key
.offset
= num_blocks
;
199 find_free_extent(trans
, root
, 0, 0, (u64
)-1, &ins
);
200 btrfs_init_path(&path
);
201 ret
= btrfs_search_slot(trans
, extent_root
, &key
, &path
, -1, 1);
203 printk("failed to find %Lu\n", key
.objectid
);
204 btrfs_print_tree(extent_root
, extent_root
->node
);
205 printk("failed to find %Lu\n", key
.objectid
);
208 ei
= btrfs_item_ptr(btrfs_buffer_leaf(path
.nodes
[0]), path
.slots
[0],
209 struct btrfs_extent_item
);
210 BUG_ON(ei
->refs
== 0);
211 refs
= btrfs_extent_refs(ei
) - 1;
212 btrfs_set_extent_refs(ei
, refs
);
214 u64 super_blocks_used
;
215 super_blocks_used
= btrfs_super_blocks_used(info
->disk_super
);
216 btrfs_set_super_blocks_used(info
->disk_super
,
217 super_blocks_used
- num_blocks
);
218 ret
= btrfs_del_item(trans
, extent_root
, &path
);
219 if (extent_root
->fs_info
->last_insert
.objectid
>
221 extent_root
->fs_info
->last_insert
.objectid
= blocknr
;
225 mark_buffer_dirty(path
.nodes
[0]);
226 btrfs_release_path(extent_root
, &path
);
227 finish_current_insert(trans
, extent_root
);
232 * find all the blocks marked as pending in the radix tree and remove
233 * them from the extent map
235 static int del_pending_extents(struct btrfs_trans_handle
*trans
, struct
236 btrfs_root
*extent_root
)
241 struct buffer_head
*gang
[4];
243 struct radix_tree_root
*radix
= &extent_root
->fs_info
->pinned_radix
;
246 ret
= radix_tree_gang_lookup_tag(
247 &extent_root
->fs_info
->pinned_radix
,
250 CTREE_EXTENT_PENDING_DEL
);
253 for (i
= 0; i
< ret
; i
++) {
254 radix_tree_tag_set(radix
, gang
[i
]->b_blocknr
,
255 CTREE_EXTENT_PINNED
);
256 radix_tree_tag_clear(radix
, gang
[i
]->b_blocknr
,
257 CTREE_EXTENT_PENDING_DEL
);
258 wret
= __free_extent(trans
, extent_root
,
259 gang
[i
]->b_blocknr
, 1);
268 * remove an extent from the root, returns 0 on success
270 int btrfs_free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
271 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
273 struct btrfs_root
*extent_root
= root
->fs_info
->extent_root
;
274 struct buffer_head
*t
;
278 if (root
== extent_root
) {
279 t
= find_tree_block(root
, blocknr
);
280 pin_down_block(root
, blocknr
, CTREE_EXTENT_PENDING_DEL
);
284 ret
= pin_down_block(root
, blocknr
, CTREE_EXTENT_PINNED
);
287 ret
= __free_extent(trans
, root
, blocknr
, num_blocks
);
288 pending_ret
= del_pending_extents(trans
, root
->fs_info
->extent_root
);
289 return ret
? ret
: pending_ret
;
293 * walks the btree of allocated extents and find a hole of a given size.
294 * The key ins is changed to record the hole:
295 * ins->objectid == block start
296 * ins->flags = BTRFS_EXTENT_ITEM_KEY
297 * ins->offset == number of blocks
298 * Any available blocks before search_start are skipped.
300 static int find_free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
301 *orig_root
, u64 num_blocks
, u64 search_start
, u64
302 search_end
, struct btrfs_key
*ins
)
304 struct btrfs_path path
;
305 struct btrfs_key key
;
312 struct btrfs_leaf
*l
;
313 struct btrfs_root
* root
= orig_root
->fs_info
->extent_root
;
314 int total_needed
= num_blocks
;
317 level
= btrfs_header_level(btrfs_buffer_header(root
->node
));
318 total_needed
+= (level
+ 1) * 3;
319 if (root
->fs_info
->last_insert
.objectid
> search_start
)
320 search_start
= root
->fs_info
->last_insert
.objectid
;
323 btrfs_set_key_type(ins
, BTRFS_EXTENT_ITEM_KEY
);
326 btrfs_init_path(&path
);
327 ins
->objectid
= search_start
;
330 ret
= btrfs_search_slot(trans
, root
, ins
, &path
, 0, 0);
334 if (path
.slots
[0] > 0)
338 l
= btrfs_buffer_leaf(path
.nodes
[0]);
339 slot
= path
.slots
[0];
340 if (slot
>= btrfs_header_nritems(&l
->header
)) {
341 ret
= btrfs_next_leaf(root
, &path
);
347 ins
->objectid
= search_start
;
348 ins
->offset
= (u64
)-1;
352 ins
->objectid
= last_block
> search_start
?
353 last_block
: search_start
;
354 ins
->offset
= (u64
)-1;
357 btrfs_disk_key_to_cpu(&key
, &l
->items
[slot
].key
);
358 if (key
.objectid
>= search_start
) {
360 if (last_block
< search_start
)
361 last_block
= search_start
;
362 hole_size
= key
.objectid
- last_block
;
363 if (hole_size
> total_needed
) {
364 ins
->objectid
= last_block
;
365 ins
->offset
= hole_size
;
371 last_block
= key
.objectid
+ key
.offset
;
376 /* we have to make sure we didn't find an extent that has already
377 * been allocated by the map tree or the original allocation
379 btrfs_release_path(root
, &path
);
380 BUG_ON(ins
->objectid
< search_start
);
381 for (test_block
= ins
->objectid
;
382 test_block
< ins
->objectid
+ total_needed
; test_block
++) {
383 if (radix_tree_lookup(&root
->fs_info
->pinned_radix
,
385 search_start
= test_block
+ 1;
389 BUG_ON(root
->fs_info
->current_insert
.offset
);
390 root
->fs_info
->current_insert
.offset
= total_needed
- num_blocks
;
391 root
->fs_info
->current_insert
.objectid
= ins
->objectid
+ num_blocks
;
392 root
->fs_info
->current_insert
.flags
= 0;
393 root
->fs_info
->last_insert
.objectid
= ins
->objectid
;
394 ins
->offset
= num_blocks
;
397 btrfs_release_path(root
, &path
);
402 * finds a free extent and does all the dirty work required for allocation
403 * returns the key for the extent through ins, and a tree buffer for
404 * the first block of the extent through buf.
406 * returns 0 if everything worked, non-zero otherwise.
408 static int alloc_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
409 *root
, u64 num_blocks
, u64 search_start
, u64
410 search_end
, u64 owner
, struct btrfs_key
*ins
)
414 u64 super_blocks_used
;
415 struct btrfs_fs_info
*info
= root
->fs_info
;
416 struct btrfs_root
*extent_root
= info
->extent_root
;
417 struct btrfs_extent_item extent_item
;
419 btrfs_set_extent_refs(&extent_item
, 1);
420 btrfs_set_extent_owner(&extent_item
, owner
);
422 if (root
== extent_root
) {
423 BUG_ON(extent_root
->fs_info
->current_insert
.offset
== 0);
424 BUG_ON(num_blocks
!= 1);
425 BUG_ON(extent_root
->fs_info
->current_insert
.flags
==
426 extent_root
->fs_info
->current_insert
.offset
);
428 ins
->objectid
= extent_root
->fs_info
->current_insert
.objectid
+
429 extent_root
->fs_info
->current_insert
.flags
++;
432 ret
= find_free_extent(trans
, root
, num_blocks
, search_start
,
437 super_blocks_used
= btrfs_super_blocks_used(info
->disk_super
);
438 btrfs_set_super_blocks_used(info
->disk_super
, super_blocks_used
+
440 ret
= btrfs_insert_item(trans
, extent_root
, ins
, &extent_item
,
441 sizeof(extent_item
));
443 finish_current_insert(trans
, extent_root
);
444 pending_ret
= del_pending_extents(trans
, extent_root
);
453 * helper function to allocate a block for a given tree
454 * returns the tree buffer or NULL.
456 struct buffer_head
*btrfs_alloc_free_block(struct btrfs_trans_handle
*trans
,
457 struct btrfs_root
*root
)
459 struct btrfs_key ins
;
461 struct buffer_head
*buf
;
463 ret
= alloc_extent(trans
, root
, 1, 0, (unsigned long)-1,
464 btrfs_header_parentid(btrfs_buffer_header(root
->node
)), &ins
);
469 buf
= find_tree_block(root
, ins
.objectid
);
470 dirty_tree_block(trans
, root
, buf
);
475 * helper function for drop_snapshot, this walks down the tree dropping ref
478 static int walk_down_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
479 *root
, struct btrfs_path
*path
, int *level
)
481 struct buffer_head
*next
;
482 struct buffer_head
*cur
;
487 ret
= lookup_block_ref(trans
, root
, path
->nodes
[*level
]->b_blocknr
,
493 * walk down to the last node level and free all the leaves
496 cur
= path
->nodes
[*level
];
497 if (path
->slots
[*level
] >=
498 btrfs_header_nritems(btrfs_buffer_header(cur
)))
500 blocknr
= btrfs_node_blockptr(btrfs_buffer_node(cur
),
501 path
->slots
[*level
]);
502 ret
= lookup_block_ref(trans
, root
, blocknr
, &refs
);
503 if (refs
!= 1 || *level
== 1) {
504 path
->slots
[*level
]++;
505 ret
= btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
510 next
= read_tree_block(root
, blocknr
);
511 if (path
->nodes
[*level
-1])
512 btrfs_block_release(root
, path
->nodes
[*level
-1]);
513 path
->nodes
[*level
-1] = next
;
514 *level
= btrfs_header_level(btrfs_buffer_header(next
));
515 path
->slots
[*level
] = 0;
518 ret
= btrfs_free_extent(trans
, root
, path
->nodes
[*level
]->b_blocknr
,
520 btrfs_block_release(root
, path
->nodes
[*level
]);
521 path
->nodes
[*level
] = NULL
;
528 * helper for dropping snapshots. This walks back up the tree in the path
529 * to find the first node higher up where we haven't yet gone through
532 static int walk_up_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
533 *root
, struct btrfs_path
*path
, int *level
)
538 for(i
= *level
; i
< BTRFS_MAX_LEVEL
- 1 && path
->nodes
[i
]; i
++) {
539 slot
= path
->slots
[i
];
540 if (slot
< btrfs_header_nritems(
541 btrfs_buffer_header(path
->nodes
[i
])) - 1) {
546 ret
= btrfs_free_extent(trans
, root
,
547 path
->nodes
[*level
]->b_blocknr
,
549 btrfs_block_release(root
, path
->nodes
[*level
]);
550 path
->nodes
[*level
] = NULL
;
559 * drop the reference count on the tree rooted at 'snap'. This traverses
560 * the tree freeing any blocks that have a ref count of zero after being
563 int btrfs_drop_snapshot(struct btrfs_trans_handle
*trans
, struct btrfs_root
564 *root
, struct buffer_head
*snap
)
569 struct btrfs_path path
;
573 btrfs_init_path(&path
);
575 level
= btrfs_header_level(btrfs_buffer_header(snap
));
577 path
.nodes
[level
] = snap
;
578 path
.slots
[level
] = 0;
580 wret
= walk_down_tree(trans
, root
, &path
, &level
);
586 wret
= walk_up_tree(trans
, root
, &path
, &level
);
592 for (i
= 0; i
<= orig_level
; i
++) {
594 btrfs_block_release(root
, path
.nodes
[i
]);