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
;
137 u64 super_blocks_used
;
138 struct btrfs_fs_info
*info
= extent_root
->fs_info
;
140 btrfs_set_extent_refs(&extent_item
, 1);
141 btrfs_set_extent_owner(&extent_item
,
142 btrfs_header_parentid(&extent_root
->node
->node
.header
));
145 btrfs_set_key_type(&ins
, BTRFS_EXTENT_ITEM_KEY
);
147 for (i
= 0; i
< extent_root
->fs_info
->current_insert
.flags
; i
++) {
148 ins
.objectid
= extent_root
->fs_info
->current_insert
.objectid
+
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);
153 ret
= btrfs_insert_item(trans
, extent_root
, &ins
, &extent_item
,
154 sizeof(extent_item
));
157 extent_root
->fs_info
->current_insert
.offset
= 0;
162 * remove an extent from the root, returns 0 on success
164 static int __free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
165 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
167 struct btrfs_path path
;
168 struct btrfs_key key
;
169 struct btrfs_fs_info
*info
= root
->fs_info
;
170 struct btrfs_root
*extent_root
= info
->extent_root
;
172 struct btrfs_extent_item
*ei
;
173 struct btrfs_key ins
;
176 BUG_ON(pin
&& num_blocks
!= 1);
177 key
.objectid
= blocknr
;
179 btrfs_set_key_type(&key
, BTRFS_EXTENT_ITEM_KEY
);
180 key
.offset
= num_blocks
;
182 find_free_extent(trans
, root
, 0, 0, (u64
)-1, &ins
);
183 btrfs_init_path(&path
);
184 ret
= btrfs_search_slot(trans
, extent_root
, &key
, &path
, -1, 1);
186 printf("failed to find %Lu\n", key
.objectid
);
187 btrfs_print_tree(extent_root
, extent_root
->node
);
188 printf("failed to find %Lu\n", key
.objectid
);
191 ei
= btrfs_item_ptr(&path
.nodes
[0]->leaf
, path
.slots
[0],
192 struct btrfs_extent_item
);
193 BUG_ON(ei
->refs
== 0);
194 refs
= btrfs_extent_refs(ei
) - 1;
195 btrfs_set_extent_refs(ei
, refs
);
197 u64 super_blocks_used
;
200 radix_tree_preload(GFP_KERNEL
);
201 err
= radix_tree_insert(&info
->pinned_radix
,
202 blocknr
, (void *)blocknr
);
204 radix_tree_preload_end();
206 super_blocks_used
= btrfs_super_blocks_used(info
->disk_super
);
207 btrfs_set_super_blocks_used(info
->disk_super
,
208 super_blocks_used
- num_blocks
);
209 ret
= btrfs_del_item(trans
, extent_root
, &path
);
210 if (!pin
&& extent_root
->fs_info
->last_insert
.objectid
>
212 extent_root
->fs_info
->last_insert
.objectid
= blocknr
;
216 btrfs_release_path(extent_root
, &path
);
217 finish_current_insert(trans
, extent_root
);
222 * find all the blocks marked as pending in the radix tree and remove
223 * them from the extent map
225 static int del_pending_extents(struct btrfs_trans_handle
*trans
, struct
226 btrfs_root
*extent_root
)
229 struct btrfs_buffer
*gang
[4];
233 ret
= radix_tree_gang_lookup_tag(
234 &extent_root
->fs_info
->cache_radix
,
237 CTREE_EXTENT_PENDING_DEL
);
240 for (i
= 0; i
< ret
; i
++) {
241 ret
= __free_extent(trans
, extent_root
,
242 gang
[i
]->blocknr
, 1, 1);
243 radix_tree_tag_clear(&extent_root
->fs_info
->cache_radix
,
245 CTREE_EXTENT_PENDING_DEL
);
246 btrfs_block_release(extent_root
, gang
[i
]);
252 static int run_pending(struct btrfs_trans_handle
*trans
, struct btrfs_root
255 while(radix_tree_tagged(&extent_root
->fs_info
->cache_radix
,
256 CTREE_EXTENT_PENDING_DEL
))
257 del_pending_extents(trans
, extent_root
);
263 * remove an extent from the root, returns 0 on success
265 int btrfs_free_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
266 *root
, u64 blocknr
, u64 num_blocks
, int pin
)
268 struct btrfs_root
*extent_root
= root
->fs_info
->extent_root
;
269 struct btrfs_buffer
*t
;
273 if (root
== extent_root
) {
274 t
= find_tree_block(root
, blocknr
);
275 radix_tree_tag_set(&root
->fs_info
->cache_radix
, blocknr
,
276 CTREE_EXTENT_PENDING_DEL
);
279 ret
= __free_extent(trans
, root
, blocknr
, num_blocks
, pin
);
280 pending_ret
= run_pending(trans
, root
->fs_info
->extent_root
);
281 return ret
? ret
: pending_ret
;
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
288 * ins->flags = BTRFS_EXTENT_ITEM_KEY
289 * ins->offset == number of blocks
290 * Any available blocks before search_start are skipped.
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
)
296 struct btrfs_path path
;
297 struct btrfs_key key
;
304 struct btrfs_leaf
*l
;
305 struct btrfs_root
* root
= orig_root
->fs_info
->extent_root
;
306 int total_needed
= num_blocks
;
308 total_needed
+= (btrfs_header_level(&root
->node
->node
.header
) + 1) * 3;
309 if (root
->fs_info
->last_insert
.objectid
> search_start
)
310 search_start
= root
->fs_info
->last_insert
.objectid
;
313 btrfs_set_key_type(ins
, BTRFS_EXTENT_ITEM_KEY
);
316 btrfs_init_path(&path
);
317 ins
->objectid
= search_start
;
320 ret
= btrfs_search_slot(trans
, root
, ins
, &path
, 0, 0);
324 if (path
.slots
[0] > 0)
328 l
= &path
.nodes
[0]->leaf
;
329 slot
= path
.slots
[0];
330 if (slot
>= btrfs_header_nritems(&l
->header
)) {
331 ret
= btrfs_next_leaf(root
, &path
);
337 ins
->objectid
= search_start
;
338 ins
->offset
= (u64
)-1;
342 ins
->objectid
= last_block
> search_start
?
343 last_block
: search_start
;
344 ins
->offset
= (u64
)-1;
347 btrfs_disk_key_to_cpu(&key
, &l
->items
[slot
].key
);
348 if (key
.objectid
>= search_start
) {
350 if (last_block
< search_start
)
351 last_block
= search_start
;
352 hole_size
= key
.objectid
- last_block
;
353 if (hole_size
> total_needed
) {
354 ins
->objectid
= last_block
;
355 ins
->offset
= hole_size
;
361 last_block
= key
.objectid
+ key
.offset
;
366 /* we have to make sure we didn't find an extent that has already
367 * been allocated by the map tree or the original allocation
369 btrfs_release_path(root
, &path
);
370 BUG_ON(ins
->objectid
< search_start
);
371 for (test_block
= ins
->objectid
;
372 test_block
< ins
->objectid
+ total_needed
; test_block
++) {
373 if (radix_tree_lookup(&root
->fs_info
->pinned_radix
,
375 search_start
= test_block
+ 1;
379 BUG_ON(root
->fs_info
->current_insert
.offset
);
380 root
->fs_info
->current_insert
.offset
= total_needed
- num_blocks
;
381 root
->fs_info
->current_insert
.objectid
= ins
->objectid
+ num_blocks
;
382 root
->fs_info
->current_insert
.flags
= 0;
383 root
->fs_info
->last_insert
.objectid
= ins
->objectid
;
384 ins
->offset
= num_blocks
;
387 btrfs_release_path(root
, &path
);
392 * finds a free extent and does all the dirty work required for allocation
393 * returns the key for the extent through ins, and a tree buffer for
394 * the first block of the extent through buf.
396 * returns 0 if everything worked, non-zero otherwise.
398 static int alloc_extent(struct btrfs_trans_handle
*trans
, struct btrfs_root
399 *root
, u64 num_blocks
, u64 search_start
, u64
400 search_end
, u64 owner
, struct btrfs_key
*ins
)
404 u64 super_blocks_used
;
405 struct btrfs_fs_info
*info
= root
->fs_info
;
406 struct btrfs_root
*extent_root
= info
->extent_root
;
407 struct btrfs_extent_item extent_item
;
409 btrfs_set_extent_refs(&extent_item
, 1);
410 btrfs_set_extent_owner(&extent_item
, owner
);
412 if (root
== extent_root
) {
413 BUG_ON(extent_root
->fs_info
->current_insert
.offset
== 0);
414 BUG_ON(num_blocks
!= 1);
415 BUG_ON(extent_root
->fs_info
->current_insert
.flags
==
416 extent_root
->fs_info
->current_insert
.offset
);
418 ins
->objectid
= extent_root
->fs_info
->current_insert
.objectid
+
419 extent_root
->fs_info
->current_insert
.flags
++;
422 ret
= find_free_extent(trans
, root
, num_blocks
, search_start
,
427 super_blocks_used
= btrfs_super_blocks_used(info
->disk_super
);
428 btrfs_set_super_blocks_used(info
->disk_super
, super_blocks_used
+
430 ret
= btrfs_insert_item(trans
, extent_root
, ins
, &extent_item
,
431 sizeof(extent_item
));
433 finish_current_insert(trans
, extent_root
);
434 pending_ret
= run_pending(trans
, extent_root
);
443 * helper function to allocate a block for a given tree
444 * returns the tree buffer or NULL.
446 struct btrfs_buffer
*btrfs_alloc_free_block(struct btrfs_trans_handle
*trans
,
447 struct btrfs_root
*root
)
449 struct btrfs_key ins
;
451 struct btrfs_buffer
*buf
;
453 ret
= alloc_extent(trans
, root
, 1, 0, (unsigned long)-1,
454 btrfs_header_parentid(&root
->node
->node
.header
),
460 buf
= find_tree_block(root
, ins
.objectid
);
461 dirty_tree_block(trans
, root
, buf
);
462 btrfs_set_header_generation(&buf
->node
.header
,
463 root
->root_key
.offset
+ 1);
468 * helper function for drop_snapshot, this walks down the tree dropping ref
471 static int walk_down_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
472 *root
, struct btrfs_path
*path
, int *level
)
474 struct btrfs_buffer
*next
;
475 struct btrfs_buffer
*cur
;
480 ret
= lookup_block_ref(trans
, root
, path
->nodes
[*level
]->blocknr
,
486 * walk down to the last node level and free all the leaves
489 cur
= path
->nodes
[*level
];
490 if (path
->slots
[*level
] >=
491 btrfs_header_nritems(&cur
->node
.header
))
493 blocknr
= btrfs_node_blockptr(&cur
->node
, path
->slots
[*level
]);
494 ret
= lookup_block_ref(trans
, root
, blocknr
, &refs
);
495 if (refs
!= 1 || *level
== 1) {
496 path
->slots
[*level
]++;
497 ret
= btrfs_free_extent(trans
, root
, blocknr
, 1, 1);
502 next
= read_tree_block(root
, blocknr
);
503 if (path
->nodes
[*level
-1])
504 btrfs_block_release(root
, path
->nodes
[*level
-1]);
505 path
->nodes
[*level
-1] = next
;
506 *level
= btrfs_header_level(&next
->node
.header
);
507 path
->slots
[*level
] = 0;
510 ret
= btrfs_free_extent(trans
, root
, path
->nodes
[*level
]->blocknr
, 1,
512 btrfs_block_release(root
, path
->nodes
[*level
]);
513 path
->nodes
[*level
] = NULL
;
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
524 static int walk_up_tree(struct btrfs_trans_handle
*trans
, struct btrfs_root
525 *root
, struct btrfs_path
*path
, int *level
)
530 for(i
= *level
; i
< BTRFS_MAX_LEVEL
- 1 && path
->nodes
[i
]; i
++) {
531 slot
= path
->slots
[i
];
533 btrfs_header_nritems(&path
->nodes
[i
]->node
.header
)- 1) {
538 ret
= btrfs_free_extent(trans
, root
,
539 path
->nodes
[*level
]->blocknr
,
541 btrfs_block_release(root
, path
->nodes
[*level
]);
542 path
->nodes
[*level
] = NULL
;
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
555 int btrfs_drop_snapshot(struct btrfs_trans_handle
*trans
, struct btrfs_root
556 *root
, struct btrfs_buffer
*snap
)
561 struct btrfs_path path
;
565 btrfs_init_path(&path
);
567 level
= btrfs_header_level(&snap
->node
.header
);
569 path
.nodes
[level
] = snap
;
570 path
.slots
[level
] = 0;
572 wret
= walk_down_tree(trans
, root
, &path
, &level
);
578 wret
= walk_up_tree(trans
, root
, &path
, &level
);
584 for (i
= 0; i
<= orig_level
; i
++) {
586 btrfs_block_release(root
, path
.nodes
[i
]);