xref: /openbmc/linux/fs/btrfs/inode.c (revision 49eb7e46d47ea72a9bd2a5f8cedb04f5159cc277)
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 #include <linux/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
23 #include <linux/fs.h>
24 #include <linux/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/smp_lock.h>
30 #include <linux/backing-dev.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/bit_spinlock.h>
37 #include <linux/version.h>
38 #include <linux/xattr.h>
39 #include <linux/posix_acl.h>
40 #include "ctree.h"
41 #include "disk-io.h"
42 #include "transaction.h"
43 #include "btrfs_inode.h"
44 #include "ioctl.h"
45 #include "print-tree.h"
46 #include "volumes.h"
47 #include "ordered-data.h"
48 #include "xattr.h"
49 #include "compat.h"
50 #include "tree-log.h"
51 
52 struct btrfs_iget_args {
53 	u64 ino;
54 	struct btrfs_root *root;
55 };
56 
57 static struct inode_operations btrfs_dir_inode_operations;
58 static struct inode_operations btrfs_symlink_inode_operations;
59 static struct inode_operations btrfs_dir_ro_inode_operations;
60 static struct inode_operations btrfs_special_inode_operations;
61 static struct inode_operations btrfs_file_inode_operations;
62 static struct address_space_operations btrfs_aops;
63 static struct address_space_operations btrfs_symlink_aops;
64 static struct file_operations btrfs_dir_file_operations;
65 static struct extent_io_ops btrfs_extent_io_ops;
66 
67 static struct kmem_cache *btrfs_inode_cachep;
68 struct kmem_cache *btrfs_trans_handle_cachep;
69 struct kmem_cache *btrfs_transaction_cachep;
70 struct kmem_cache *btrfs_bit_radix_cachep;
71 struct kmem_cache *btrfs_path_cachep;
72 
73 #define S_SHIFT 12
74 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
75 	[S_IFREG >> S_SHIFT]	= BTRFS_FT_REG_FILE,
76 	[S_IFDIR >> S_SHIFT]	= BTRFS_FT_DIR,
77 	[S_IFCHR >> S_SHIFT]	= BTRFS_FT_CHRDEV,
78 	[S_IFBLK >> S_SHIFT]	= BTRFS_FT_BLKDEV,
79 	[S_IFIFO >> S_SHIFT]	= BTRFS_FT_FIFO,
80 	[S_IFSOCK >> S_SHIFT]	= BTRFS_FT_SOCK,
81 	[S_IFLNK >> S_SHIFT]	= BTRFS_FT_SYMLINK,
82 };
83 
84 static void btrfs_truncate(struct inode *inode);
85 
86 int btrfs_check_free_space(struct btrfs_root *root, u64 num_required,
87 			   int for_del)
88 {
89 	u64 total;
90 	u64 used;
91 	u64 thresh;
92 	unsigned long flags;
93 	int ret = 0;
94 
95 	spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
96 	total = btrfs_super_total_bytes(&root->fs_info->super_copy);
97 	used = btrfs_super_bytes_used(&root->fs_info->super_copy);
98 	if (for_del)
99 		thresh = total * 90;
100 	else
101 		thresh = total * 85;
102 
103 	do_div(thresh, 100);
104 
105 	if (used + root->fs_info->delalloc_bytes + num_required > thresh)
106 		ret = -ENOSPC;
107 	spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);
108 	return ret;
109 }
110 
111 static int cow_file_range(struct inode *inode, u64 start, u64 end)
112 {
113 	struct btrfs_root *root = BTRFS_I(inode)->root;
114 	struct btrfs_trans_handle *trans;
115 	u64 alloc_hint = 0;
116 	u64 num_bytes;
117 	u64 cur_alloc_size;
118 	u64 blocksize = root->sectorsize;
119 	u64 orig_num_bytes;
120 	struct btrfs_key ins;
121 	struct extent_map *em;
122 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
123 	int ret = 0;
124 
125 	trans = btrfs_join_transaction(root, 1);
126 	BUG_ON(!trans);
127 	btrfs_set_trans_block_group(trans, inode);
128 
129 	num_bytes = (end - start + blocksize) & ~(blocksize - 1);
130 	num_bytes = max(blocksize,  num_bytes);
131 	orig_num_bytes = num_bytes;
132 
133 	if (alloc_hint == EXTENT_MAP_INLINE)
134 		goto out;
135 
136 	BUG_ON(num_bytes > btrfs_super_total_bytes(&root->fs_info->super_copy));
137 	mutex_lock(&BTRFS_I(inode)->extent_mutex);
138 	btrfs_drop_extent_cache(inode, start, start + num_bytes - 1);
139 	mutex_unlock(&BTRFS_I(inode)->extent_mutex);
140 
141 	while(num_bytes > 0) {
142 		cur_alloc_size = min(num_bytes, root->fs_info->max_extent);
143 		ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
144 					   root->sectorsize, 0, 0,
145 					   (u64)-1, &ins, 1);
146 		if (ret) {
147 			WARN_ON(1);
148 			goto out;
149 		}
150 		em = alloc_extent_map(GFP_NOFS);
151 		em->start = start;
152 		em->len = ins.offset;
153 		em->block_start = ins.objectid;
154 		em->bdev = root->fs_info->fs_devices->latest_bdev;
155 		mutex_lock(&BTRFS_I(inode)->extent_mutex);
156 		set_bit(EXTENT_FLAG_PINNED, &em->flags);
157 		while(1) {
158 			spin_lock(&em_tree->lock);
159 			ret = add_extent_mapping(em_tree, em);
160 			spin_unlock(&em_tree->lock);
161 			if (ret != -EEXIST) {
162 				free_extent_map(em);
163 				break;
164 			}
165 			btrfs_drop_extent_cache(inode, start,
166 						start + ins.offset - 1);
167 		}
168 		mutex_unlock(&BTRFS_I(inode)->extent_mutex);
169 
170 		cur_alloc_size = ins.offset;
171 		ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
172 					       ins.offset, 0);
173 		BUG_ON(ret);
174 		if (num_bytes < cur_alloc_size) {
175 			printk("num_bytes %Lu cur_alloc %Lu\n", num_bytes,
176 			       cur_alloc_size);
177 			break;
178 		}
179 		num_bytes -= cur_alloc_size;
180 		alloc_hint = ins.objectid + ins.offset;
181 		start += cur_alloc_size;
182 	}
183 out:
184 	btrfs_end_transaction(trans, root);
185 	return ret;
186 }
187 
188 static int run_delalloc_nocow(struct inode *inode, u64 start, u64 end)
189 {
190 	u64 extent_start;
191 	u64 extent_end;
192 	u64 bytenr;
193 	u64 loops = 0;
194 	u64 total_fs_bytes;
195 	struct btrfs_root *root = BTRFS_I(inode)->root;
196 	struct btrfs_block_group_cache *block_group;
197 	struct btrfs_trans_handle *trans;
198 	struct extent_buffer *leaf;
199 	int found_type;
200 	struct btrfs_path *path;
201 	struct btrfs_file_extent_item *item;
202 	int ret;
203 	int err = 0;
204 	struct btrfs_key found_key;
205 
206 	total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
207 	path = btrfs_alloc_path();
208 	BUG_ON(!path);
209 	trans = btrfs_join_transaction(root, 1);
210 	BUG_ON(!trans);
211 again:
212 	ret = btrfs_lookup_file_extent(NULL, root, path,
213 				       inode->i_ino, start, 0);
214 	if (ret < 0) {
215 		err = ret;
216 		goto out;
217 	}
218 
219 	if (ret != 0) {
220 		if (path->slots[0] == 0)
221 			goto not_found;
222 		path->slots[0]--;
223 	}
224 
225 	leaf = path->nodes[0];
226 	item = btrfs_item_ptr(leaf, path->slots[0],
227 			      struct btrfs_file_extent_item);
228 
229 	/* are we inside the extent that was found? */
230 	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
231 	found_type = btrfs_key_type(&found_key);
232 	if (found_key.objectid != inode->i_ino ||
233 	    found_type != BTRFS_EXTENT_DATA_KEY)
234 		goto not_found;
235 
236 	found_type = btrfs_file_extent_type(leaf, item);
237 	extent_start = found_key.offset;
238 	if (found_type == BTRFS_FILE_EXTENT_REG) {
239 		u64 extent_num_bytes;
240 
241 		extent_num_bytes = btrfs_file_extent_num_bytes(leaf, item);
242 		extent_end = extent_start + extent_num_bytes;
243 		err = 0;
244 
245 		if (loops && start != extent_start)
246 			goto not_found;
247 
248 		if (start < extent_start || start >= extent_end)
249 			goto not_found;
250 
251 		bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
252 		if (bytenr == 0)
253 			goto not_found;
254 
255 		if (btrfs_cross_ref_exists(trans, root, &found_key, bytenr))
256 			goto not_found;
257 		/*
258 		 * we may be called by the resizer, make sure we're inside
259 		 * the limits of the FS
260 		 */
261 		block_group = btrfs_lookup_block_group(root->fs_info,
262 						       bytenr);
263 		if (!block_group || block_group->ro)
264 			goto not_found;
265 
266 		bytenr += btrfs_file_extent_offset(leaf, item);
267 		extent_num_bytes = min(end + 1, extent_end) - start;
268 		ret = btrfs_add_ordered_extent(inode, start, bytenr,
269 						extent_num_bytes, 1);
270 		if (ret) {
271 			err = ret;
272 			goto out;
273 		}
274 
275 		btrfs_release_path(root, path);
276 		start = extent_end;
277 		if (start <= end) {
278 			loops++;
279 			goto again;
280 		}
281 	} else {
282 not_found:
283 		btrfs_end_transaction(trans, root);
284 		btrfs_free_path(path);
285 		return cow_file_range(inode, start, end);
286 	}
287 out:
288 	WARN_ON(err);
289 	btrfs_end_transaction(trans, root);
290 	btrfs_free_path(path);
291 	return err;
292 }
293 
294 static int run_delalloc_range(struct inode *inode, u64 start, u64 end)
295 {
296 	struct btrfs_root *root = BTRFS_I(inode)->root;
297 	int ret;
298 
299 	if (btrfs_test_opt(root, NODATACOW) ||
300 	    btrfs_test_flag(inode, NODATACOW))
301 		ret = run_delalloc_nocow(inode, start, end);
302 	else
303 		ret = cow_file_range(inode, start, end);
304 
305 	return ret;
306 }
307 
308 int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
309 		       unsigned long old, unsigned long bits)
310 {
311 	unsigned long flags;
312 	if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
313 		struct btrfs_root *root = BTRFS_I(inode)->root;
314 		spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
315 		BTRFS_I(inode)->delalloc_bytes += end - start + 1;
316 		root->fs_info->delalloc_bytes += end - start + 1;
317 		if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
318 			list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
319 				      &root->fs_info->delalloc_inodes);
320 		}
321 		spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);
322 	}
323 	return 0;
324 }
325 
326 int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end,
327 			 unsigned long old, unsigned long bits)
328 {
329 	if ((old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
330 		struct btrfs_root *root = BTRFS_I(inode)->root;
331 		unsigned long flags;
332 
333 		spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
334 		if (end - start + 1 > root->fs_info->delalloc_bytes) {
335 			printk("warning: delalloc account %Lu %Lu\n",
336 			       end - start + 1, root->fs_info->delalloc_bytes);
337 			root->fs_info->delalloc_bytes = 0;
338 			BTRFS_I(inode)->delalloc_bytes = 0;
339 		} else {
340 			root->fs_info->delalloc_bytes -= end - start + 1;
341 			BTRFS_I(inode)->delalloc_bytes -= end - start + 1;
342 		}
343 		if (BTRFS_I(inode)->delalloc_bytes == 0 &&
344 		    !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
345 			list_del_init(&BTRFS_I(inode)->delalloc_inodes);
346 		}
347 		spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);
348 	}
349 	return 0;
350 }
351 
352 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
353 			 size_t size, struct bio *bio)
354 {
355 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
356 	struct btrfs_mapping_tree *map_tree;
357 	u64 logical = bio->bi_sector << 9;
358 	u64 length = 0;
359 	u64 map_length;
360 	int ret;
361 
362 	length = bio->bi_size;
363 	map_tree = &root->fs_info->mapping_tree;
364 	map_length = length;
365 	ret = btrfs_map_block(map_tree, READ, logical,
366 			      &map_length, NULL, 0);
367 
368 	if (map_length < length + size) {
369 		return 1;
370 	}
371 	return 0;
372 }
373 
374 int __btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
375 			  int mirror_num)
376 {
377 	struct btrfs_root *root = BTRFS_I(inode)->root;
378 	int ret = 0;
379 
380 	ret = btrfs_csum_one_bio(root, inode, bio);
381 	BUG_ON(ret);
382 
383 	return btrfs_map_bio(root, rw, bio, mirror_num, 1);
384 }
385 
386 int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
387 			  int mirror_num)
388 {
389 	struct btrfs_root *root = BTRFS_I(inode)->root;
390 	int ret = 0;
391 
392 	ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
393 	BUG_ON(ret);
394 
395 	if (btrfs_test_opt(root, NODATASUM) ||
396 	    btrfs_test_flag(inode, NODATASUM)) {
397 		goto mapit;
398 	}
399 
400 	if (!(rw & (1 << BIO_RW))) {
401 		btrfs_lookup_bio_sums(root, inode, bio);
402 		goto mapit;
403 	}
404 	return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
405 				   inode, rw, bio, mirror_num,
406 				   __btrfs_submit_bio_hook);
407 mapit:
408 	return btrfs_map_bio(root, rw, bio, mirror_num, 0);
409 }
410 
411 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
412 			     struct inode *inode, u64 file_offset,
413 			     struct list_head *list)
414 {
415 	struct list_head *cur;
416 	struct btrfs_ordered_sum *sum;
417 
418 	btrfs_set_trans_block_group(trans, inode);
419 	list_for_each(cur, list) {
420 		sum = list_entry(cur, struct btrfs_ordered_sum, list);
421 		btrfs_csum_file_blocks(trans, BTRFS_I(inode)->root,
422 				       inode, sum);
423 	}
424 	return 0;
425 }
426 
427 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end)
428 {
429 	return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
430 				   GFP_NOFS);
431 }
432 
433 struct btrfs_writepage_fixup {
434 	struct page *page;
435 	struct btrfs_work work;
436 };
437 
438 /* see btrfs_writepage_start_hook for details on why this is required */
439 void btrfs_writepage_fixup_worker(struct btrfs_work *work)
440 {
441 	struct btrfs_writepage_fixup *fixup;
442 	struct btrfs_ordered_extent *ordered;
443 	struct page *page;
444 	struct inode *inode;
445 	u64 page_start;
446 	u64 page_end;
447 
448 	fixup = container_of(work, struct btrfs_writepage_fixup, work);
449 	page = fixup->page;
450 again:
451 	lock_page(page);
452 	if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
453 		ClearPageChecked(page);
454 		goto out_page;
455 	}
456 
457 	inode = page->mapping->host;
458 	page_start = page_offset(page);
459 	page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
460 
461 	lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
462 
463 	/* already ordered? We're done */
464 	if (test_range_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
465 			     EXTENT_ORDERED, 0)) {
466 		goto out;
467 	}
468 
469 	ordered = btrfs_lookup_ordered_extent(inode, page_start);
470 	if (ordered) {
471 		unlock_extent(&BTRFS_I(inode)->io_tree, page_start,
472 			      page_end, GFP_NOFS);
473 		unlock_page(page);
474 		btrfs_start_ordered_extent(inode, ordered, 1);
475 		goto again;
476 	}
477 
478 	btrfs_set_extent_delalloc(inode, page_start, page_end);
479 	ClearPageChecked(page);
480 out:
481 	unlock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
482 out_page:
483 	unlock_page(page);
484 	page_cache_release(page);
485 }
486 
487 /*
488  * There are a few paths in the higher layers of the kernel that directly
489  * set the page dirty bit without asking the filesystem if it is a
490  * good idea.  This causes problems because we want to make sure COW
491  * properly happens and the data=ordered rules are followed.
492  *
493  * In our case any range that doesn't have the EXTENT_ORDERED bit set
494  * hasn't been properly setup for IO.  We kick off an async process
495  * to fix it up.  The async helper will wait for ordered extents, set
496  * the delalloc bit and make it safe to write the page.
497  */
498 int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
499 {
500 	struct inode *inode = page->mapping->host;
501 	struct btrfs_writepage_fixup *fixup;
502 	struct btrfs_root *root = BTRFS_I(inode)->root;
503 	int ret;
504 
505 	ret = test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
506 			     EXTENT_ORDERED, 0);
507 	if (ret)
508 		return 0;
509 
510 	if (PageChecked(page))
511 		return -EAGAIN;
512 
513 	fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
514 	if (!fixup)
515 		return -EAGAIN;
516 
517 	SetPageChecked(page);
518 	page_cache_get(page);
519 	fixup->work.func = btrfs_writepage_fixup_worker;
520 	fixup->page = page;
521 	btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
522 	return -EAGAIN;
523 }
524 
525 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
526 {
527 	struct btrfs_root *root = BTRFS_I(inode)->root;
528 	struct btrfs_trans_handle *trans;
529 	struct btrfs_ordered_extent *ordered_extent;
530 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
531 	u64 alloc_hint = 0;
532 	struct list_head list;
533 	struct btrfs_key ins;
534 	int ret;
535 
536 	ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
537 	if (!ret)
538 		return 0;
539 
540 	trans = btrfs_join_transaction(root, 1);
541 
542 	ordered_extent = btrfs_lookup_ordered_extent(inode, start);
543 	BUG_ON(!ordered_extent);
544 	if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
545 		goto nocow;
546 
547 	lock_extent(io_tree, ordered_extent->file_offset,
548 		    ordered_extent->file_offset + ordered_extent->len - 1,
549 		    GFP_NOFS);
550 
551 	INIT_LIST_HEAD(&list);
552 
553 	ins.objectid = ordered_extent->start;
554 	ins.offset = ordered_extent->len;
555 	ins.type = BTRFS_EXTENT_ITEM_KEY;
556 
557 	ret = btrfs_alloc_reserved_extent(trans, root, root->root_key.objectid,
558 					  trans->transid, inode->i_ino,
559 					  ordered_extent->file_offset, &ins);
560 	BUG_ON(ret);
561 
562 	mutex_lock(&BTRFS_I(inode)->extent_mutex);
563 
564 	ret = btrfs_drop_extents(trans, root, inode,
565 				 ordered_extent->file_offset,
566 				 ordered_extent->file_offset +
567 				 ordered_extent->len,
568 				 ordered_extent->file_offset, &alloc_hint);
569 	BUG_ON(ret);
570 	ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
571 				       ordered_extent->file_offset,
572 				       ordered_extent->start,
573 				       ordered_extent->len,
574 				       ordered_extent->len, 0);
575 	BUG_ON(ret);
576 
577 	btrfs_drop_extent_cache(inode, ordered_extent->file_offset,
578 				ordered_extent->file_offset +
579 				ordered_extent->len - 1);
580 	mutex_unlock(&BTRFS_I(inode)->extent_mutex);
581 
582 	inode->i_blocks += ordered_extent->len >> 9;
583 	unlock_extent(io_tree, ordered_extent->file_offset,
584 		    ordered_extent->file_offset + ordered_extent->len - 1,
585 		    GFP_NOFS);
586 nocow:
587 	add_pending_csums(trans, inode, ordered_extent->file_offset,
588 			  &ordered_extent->list);
589 
590 	btrfs_ordered_update_i_size(inode, ordered_extent);
591 	btrfs_update_inode(trans, root, inode);
592 	btrfs_remove_ordered_extent(inode, ordered_extent);
593 
594 	/* once for us */
595 	btrfs_put_ordered_extent(ordered_extent);
596 	/* once for the tree */
597 	btrfs_put_ordered_extent(ordered_extent);
598 
599 	btrfs_end_transaction(trans, root);
600 	return 0;
601 }
602 
603 int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
604 				struct extent_state *state, int uptodate)
605 {
606 	return btrfs_finish_ordered_io(page->mapping->host, start, end);
607 }
608 
609 struct io_failure_record {
610 	struct page *page;
611 	u64 start;
612 	u64 len;
613 	u64 logical;
614 	int last_mirror;
615 };
616 
617 int btrfs_io_failed_hook(struct bio *failed_bio,
618 			 struct page *page, u64 start, u64 end,
619 			 struct extent_state *state)
620 {
621 	struct io_failure_record *failrec = NULL;
622 	u64 private;
623 	struct extent_map *em;
624 	struct inode *inode = page->mapping->host;
625 	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
626 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
627 	struct bio *bio;
628 	int num_copies;
629 	int ret;
630 	int rw;
631 	u64 logical;
632 
633 	ret = get_state_private(failure_tree, start, &private);
634 	if (ret) {
635 		failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
636 		if (!failrec)
637 			return -ENOMEM;
638 		failrec->start = start;
639 		failrec->len = end - start + 1;
640 		failrec->last_mirror = 0;
641 
642 		spin_lock(&em_tree->lock);
643 		em = lookup_extent_mapping(em_tree, start, failrec->len);
644 		if (em->start > start || em->start + em->len < start) {
645 			free_extent_map(em);
646 			em = NULL;
647 		}
648 		spin_unlock(&em_tree->lock);
649 
650 		if (!em || IS_ERR(em)) {
651 			kfree(failrec);
652 			return -EIO;
653 		}
654 		logical = start - em->start;
655 		logical = em->block_start + logical;
656 		failrec->logical = logical;
657 		free_extent_map(em);
658 		set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
659 				EXTENT_DIRTY, GFP_NOFS);
660 		set_state_private(failure_tree, start,
661 				 (u64)(unsigned long)failrec);
662 	} else {
663 		failrec = (struct io_failure_record *)(unsigned long)private;
664 	}
665 	num_copies = btrfs_num_copies(
666 			      &BTRFS_I(inode)->root->fs_info->mapping_tree,
667 			      failrec->logical, failrec->len);
668 	failrec->last_mirror++;
669 	if (!state) {
670 		spin_lock_irq(&BTRFS_I(inode)->io_tree.lock);
671 		state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
672 						    failrec->start,
673 						    EXTENT_LOCKED);
674 		if (state && state->start != failrec->start)
675 			state = NULL;
676 		spin_unlock_irq(&BTRFS_I(inode)->io_tree.lock);
677 	}
678 	if (!state || failrec->last_mirror > num_copies) {
679 		set_state_private(failure_tree, failrec->start, 0);
680 		clear_extent_bits(failure_tree, failrec->start,
681 				  failrec->start + failrec->len - 1,
682 				  EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
683 		kfree(failrec);
684 		return -EIO;
685 	}
686 	bio = bio_alloc(GFP_NOFS, 1);
687 	bio->bi_private = state;
688 	bio->bi_end_io = failed_bio->bi_end_io;
689 	bio->bi_sector = failrec->logical >> 9;
690 	bio->bi_bdev = failed_bio->bi_bdev;
691 	bio->bi_size = 0;
692 	bio_add_page(bio, page, failrec->len, start - page_offset(page));
693 	if (failed_bio->bi_rw & (1 << BIO_RW))
694 		rw = WRITE;
695 	else
696 		rw = READ;
697 
698 	BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
699 						      failrec->last_mirror);
700 	return 0;
701 }
702 
703 int btrfs_clean_io_failures(struct inode *inode, u64 start)
704 {
705 	u64 private;
706 	u64 private_failure;
707 	struct io_failure_record *failure;
708 	int ret;
709 
710 	private = 0;
711 	if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
712 			     (u64)-1, 1, EXTENT_DIRTY)) {
713 		ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
714 					start, &private_failure);
715 		if (ret == 0) {
716 			failure = (struct io_failure_record *)(unsigned long)
717 				   private_failure;
718 			set_state_private(&BTRFS_I(inode)->io_failure_tree,
719 					  failure->start, 0);
720 			clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
721 					  failure->start,
722 					  failure->start + failure->len - 1,
723 					  EXTENT_DIRTY | EXTENT_LOCKED,
724 					  GFP_NOFS);
725 			kfree(failure);
726 		}
727 	}
728 	return 0;
729 }
730 
731 int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
732 			       struct extent_state *state)
733 {
734 	size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
735 	struct inode *inode = page->mapping->host;
736 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
737 	char *kaddr;
738 	u64 private = ~(u32)0;
739 	int ret;
740 	struct btrfs_root *root = BTRFS_I(inode)->root;
741 	u32 csum = ~(u32)0;
742 	unsigned long flags;
743 
744 	if (btrfs_test_opt(root, NODATASUM) ||
745 	    btrfs_test_flag(inode, NODATASUM))
746 		return 0;
747 	if (state && state->start == start) {
748 		private = state->private;
749 		ret = 0;
750 	} else {
751 		ret = get_state_private(io_tree, start, &private);
752 	}
753 	local_irq_save(flags);
754 	kaddr = kmap_atomic(page, KM_IRQ0);
755 	if (ret) {
756 		goto zeroit;
757 	}
758 	csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
759 	btrfs_csum_final(csum, (char *)&csum);
760 	if (csum != private) {
761 		goto zeroit;
762 	}
763 	kunmap_atomic(kaddr, KM_IRQ0);
764 	local_irq_restore(flags);
765 
766 	/* if the io failure tree for this inode is non-empty,
767 	 * check to see if we've recovered from a failed IO
768 	 */
769 	btrfs_clean_io_failures(inode, start);
770 	return 0;
771 
772 zeroit:
773 	printk("btrfs csum failed ino %lu off %llu csum %u private %Lu\n",
774 	       page->mapping->host->i_ino, (unsigned long long)start, csum,
775 	       private);
776 	memset(kaddr + offset, 1, end - start + 1);
777 	flush_dcache_page(page);
778 	kunmap_atomic(kaddr, KM_IRQ0);
779 	local_irq_restore(flags);
780 	if (private == 0)
781 		return 0;
782 	return -EIO;
783 }
784 
785 /*
786  * This creates an orphan entry for the given inode in case something goes
787  * wrong in the middle of an unlink/truncate.
788  */
789 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
790 {
791 	struct btrfs_root *root = BTRFS_I(inode)->root;
792 	int ret = 0;
793 
794 	spin_lock(&root->list_lock);
795 
796 	/* already on the orphan list, we're good */
797 	if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
798 		spin_unlock(&root->list_lock);
799 		return 0;
800 	}
801 
802 	list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
803 
804 	spin_unlock(&root->list_lock);
805 
806 	/*
807 	 * insert an orphan item to track this unlinked/truncated file
808 	 */
809 	ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
810 
811 	return ret;
812 }
813 
814 /*
815  * We have done the truncate/delete so we can go ahead and remove the orphan
816  * item for this particular inode.
817  */
818 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
819 {
820 	struct btrfs_root *root = BTRFS_I(inode)->root;
821 	int ret = 0;
822 
823 	spin_lock(&root->list_lock);
824 
825 	if (list_empty(&BTRFS_I(inode)->i_orphan)) {
826 		spin_unlock(&root->list_lock);
827 		return 0;
828 	}
829 
830 	list_del_init(&BTRFS_I(inode)->i_orphan);
831 	if (!trans) {
832 		spin_unlock(&root->list_lock);
833 		return 0;
834 	}
835 
836 	spin_unlock(&root->list_lock);
837 
838 	ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
839 
840 	return ret;
841 }
842 
843 /*
844  * this cleans up any orphans that may be left on the list from the last use
845  * of this root.
846  */
847 void btrfs_orphan_cleanup(struct btrfs_root *root)
848 {
849 	struct btrfs_path *path;
850 	struct extent_buffer *leaf;
851 	struct btrfs_item *item;
852 	struct btrfs_key key, found_key;
853 	struct btrfs_trans_handle *trans;
854 	struct inode *inode;
855 	int ret = 0, nr_unlink = 0, nr_truncate = 0;
856 
857 	/* don't do orphan cleanup if the fs is readonly. */
858 	if (root->inode->i_sb->s_flags & MS_RDONLY)
859 		return;
860 
861 	path = btrfs_alloc_path();
862 	if (!path)
863 		return;
864 	path->reada = -1;
865 
866 	key.objectid = BTRFS_ORPHAN_OBJECTID;
867 	btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
868 	key.offset = (u64)-1;
869 
870 	trans = btrfs_start_transaction(root, 1);
871 	btrfs_set_trans_block_group(trans, root->inode);
872 
873 	while (1) {
874 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
875 		if (ret < 0) {
876 			printk(KERN_ERR "Error searching slot for orphan: %d"
877 			       "\n", ret);
878 			break;
879 		}
880 
881 		/*
882 		 * if ret == 0 means we found what we were searching for, which
883 		 * is weird, but possible, so only screw with path if we didnt
884 		 * find the key and see if we have stuff that matches
885 		 */
886 		if (ret > 0) {
887 			if (path->slots[0] == 0)
888 				break;
889 			path->slots[0]--;
890 		}
891 
892 		/* pull out the item */
893 		leaf = path->nodes[0];
894 		item = btrfs_item_nr(leaf, path->slots[0]);
895 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
896 
897 		/* make sure the item matches what we want */
898 		if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
899 			break;
900 		if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
901 			break;
902 
903 		/* release the path since we're done with it */
904 		btrfs_release_path(root, path);
905 
906 		/*
907 		 * this is where we are basically btrfs_lookup, without the
908 		 * crossing root thing.  we store the inode number in the
909 		 * offset of the orphan item.
910 		 */
911 		inode = btrfs_iget_locked(root->inode->i_sb,
912 					  found_key.offset, root);
913 		if (!inode)
914 			break;
915 
916 		if (inode->i_state & I_NEW) {
917 			BTRFS_I(inode)->root = root;
918 
919 			/* have to set the location manually */
920 			BTRFS_I(inode)->location.objectid = inode->i_ino;
921 			BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
922 			BTRFS_I(inode)->location.offset = 0;
923 
924 			btrfs_read_locked_inode(inode);
925 			unlock_new_inode(inode);
926 		}
927 
928 		/*
929 		 * add this inode to the orphan list so btrfs_orphan_del does
930 		 * the proper thing when we hit it
931 		 */
932 		spin_lock(&root->list_lock);
933 		list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
934 		spin_unlock(&root->list_lock);
935 
936 		/*
937 		 * if this is a bad inode, means we actually succeeded in
938 		 * removing the inode, but not the orphan record, which means
939 		 * we need to manually delete the orphan since iput will just
940 		 * do a destroy_inode
941 		 */
942 		if (is_bad_inode(inode)) {
943 			btrfs_orphan_del(trans, inode);
944 			iput(inode);
945 			continue;
946 		}
947 
948 		/* if we have links, this was a truncate, lets do that */
949 		if (inode->i_nlink) {
950 			nr_truncate++;
951 			btrfs_truncate(inode);
952 		} else {
953 			nr_unlink++;
954 		}
955 
956 		/* this will do delete_inode and everything for us */
957 		iput(inode);
958 	}
959 
960 	if (nr_unlink)
961 		printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
962 	if (nr_truncate)
963 		printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
964 
965 	btrfs_free_path(path);
966 	btrfs_end_transaction(trans, root);
967 }
968 
969 void btrfs_read_locked_inode(struct inode *inode)
970 {
971 	struct btrfs_path *path;
972 	struct extent_buffer *leaf;
973 	struct btrfs_inode_item *inode_item;
974 	struct btrfs_timespec *tspec;
975 	struct btrfs_root *root = BTRFS_I(inode)->root;
976 	struct btrfs_key location;
977 	u64 alloc_group_block;
978 	u32 rdev;
979 	int ret;
980 
981 	path = btrfs_alloc_path();
982 	BUG_ON(!path);
983 	memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
984 
985 	ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
986 	if (ret)
987 		goto make_bad;
988 
989 	leaf = path->nodes[0];
990 	inode_item = btrfs_item_ptr(leaf, path->slots[0],
991 				    struct btrfs_inode_item);
992 
993 	inode->i_mode = btrfs_inode_mode(leaf, inode_item);
994 	inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
995 	inode->i_uid = btrfs_inode_uid(leaf, inode_item);
996 	inode->i_gid = btrfs_inode_gid(leaf, inode_item);
997 	btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
998 
999 	tspec = btrfs_inode_atime(inode_item);
1000 	inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
1001 	inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
1002 
1003 	tspec = btrfs_inode_mtime(inode_item);
1004 	inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
1005 	inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
1006 
1007 	tspec = btrfs_inode_ctime(inode_item);
1008 	inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
1009 	inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
1010 
1011 	inode->i_blocks = btrfs_inode_nblocks(leaf, inode_item);
1012 	BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
1013 	inode->i_generation = BTRFS_I(inode)->generation;
1014 	inode->i_rdev = 0;
1015 	rdev = btrfs_inode_rdev(leaf, inode_item);
1016 
1017 	BTRFS_I(inode)->index_cnt = (u64)-1;
1018 
1019 	alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
1020 	BTRFS_I(inode)->block_group = btrfs_lookup_block_group(root->fs_info,
1021 						       alloc_group_block);
1022 	BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
1023 	if (!BTRFS_I(inode)->block_group) {
1024 		BTRFS_I(inode)->block_group = btrfs_find_block_group(root,
1025 						 NULL, 0,
1026 						 BTRFS_BLOCK_GROUP_METADATA, 0);
1027 	}
1028 	btrfs_free_path(path);
1029 	inode_item = NULL;
1030 
1031 	switch (inode->i_mode & S_IFMT) {
1032 	case S_IFREG:
1033 		inode->i_mapping->a_ops = &btrfs_aops;
1034 		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
1035 		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
1036 		inode->i_fop = &btrfs_file_operations;
1037 		inode->i_op = &btrfs_file_inode_operations;
1038 		break;
1039 	case S_IFDIR:
1040 		inode->i_fop = &btrfs_dir_file_operations;
1041 		if (root == root->fs_info->tree_root)
1042 			inode->i_op = &btrfs_dir_ro_inode_operations;
1043 		else
1044 			inode->i_op = &btrfs_dir_inode_operations;
1045 		break;
1046 	case S_IFLNK:
1047 		inode->i_op = &btrfs_symlink_inode_operations;
1048 		inode->i_mapping->a_ops = &btrfs_symlink_aops;
1049 		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
1050 		break;
1051 	default:
1052 		init_special_inode(inode, inode->i_mode, rdev);
1053 		break;
1054 	}
1055 	return;
1056 
1057 make_bad:
1058 	btrfs_free_path(path);
1059 	make_bad_inode(inode);
1060 }
1061 
1062 static void fill_inode_item(struct btrfs_trans_handle *trans,
1063 			    struct extent_buffer *leaf,
1064 			    struct btrfs_inode_item *item,
1065 			    struct inode *inode)
1066 {
1067 	btrfs_set_inode_uid(leaf, item, inode->i_uid);
1068 	btrfs_set_inode_gid(leaf, item, inode->i_gid);
1069 	btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
1070 	btrfs_set_inode_mode(leaf, item, inode->i_mode);
1071 	btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
1072 
1073 	btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
1074 			       inode->i_atime.tv_sec);
1075 	btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
1076 				inode->i_atime.tv_nsec);
1077 
1078 	btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
1079 			       inode->i_mtime.tv_sec);
1080 	btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
1081 				inode->i_mtime.tv_nsec);
1082 
1083 	btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
1084 			       inode->i_ctime.tv_sec);
1085 	btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
1086 				inode->i_ctime.tv_nsec);
1087 
1088 	btrfs_set_inode_nblocks(leaf, item, inode->i_blocks);
1089 	btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
1090 	btrfs_set_inode_transid(leaf, item, trans->transid);
1091 	btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
1092 	btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
1093 	btrfs_set_inode_block_group(leaf, item,
1094 				    BTRFS_I(inode)->block_group->key.objectid);
1095 }
1096 
1097 int noinline btrfs_update_inode(struct btrfs_trans_handle *trans,
1098 			      struct btrfs_root *root,
1099 			      struct inode *inode)
1100 {
1101 	struct btrfs_inode_item *inode_item;
1102 	struct btrfs_path *path;
1103 	struct extent_buffer *leaf;
1104 	int ret;
1105 
1106 	path = btrfs_alloc_path();
1107 	BUG_ON(!path);
1108 	ret = btrfs_lookup_inode(trans, root, path,
1109 				 &BTRFS_I(inode)->location, 1);
1110 	if (ret) {
1111 		if (ret > 0)
1112 			ret = -ENOENT;
1113 		goto failed;
1114 	}
1115 
1116 	leaf = path->nodes[0];
1117 	inode_item = btrfs_item_ptr(leaf, path->slots[0],
1118 				  struct btrfs_inode_item);
1119 
1120 	fill_inode_item(trans, leaf, inode_item, inode);
1121 	btrfs_mark_buffer_dirty(leaf);
1122 	btrfs_set_inode_last_trans(trans, inode);
1123 	ret = 0;
1124 failed:
1125 	btrfs_free_path(path);
1126 	return ret;
1127 }
1128 
1129 
1130 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
1131 		       struct btrfs_root *root,
1132 		       struct inode *dir, struct inode *inode,
1133 		       const char *name, int name_len)
1134 {
1135 	struct btrfs_path *path;
1136 	int ret = 0;
1137 	struct extent_buffer *leaf;
1138 	struct btrfs_dir_item *di;
1139 	struct btrfs_key key;
1140 	u64 index;
1141 
1142 	path = btrfs_alloc_path();
1143 	if (!path) {
1144 		ret = -ENOMEM;
1145 		goto err;
1146 	}
1147 
1148 	di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
1149 				    name, name_len, -1);
1150 	if (IS_ERR(di)) {
1151 		ret = PTR_ERR(di);
1152 		goto err;
1153 	}
1154 	if (!di) {
1155 		ret = -ENOENT;
1156 		goto err;
1157 	}
1158 	leaf = path->nodes[0];
1159 	btrfs_dir_item_key_to_cpu(leaf, di, &key);
1160 	ret = btrfs_delete_one_dir_name(trans, root, path, di);
1161 	if (ret)
1162 		goto err;
1163 	btrfs_release_path(root, path);
1164 
1165 	ret = btrfs_del_inode_ref(trans, root, name, name_len,
1166 				  inode->i_ino,
1167 				  dir->i_ino, &index);
1168 	if (ret) {
1169 		printk("failed to delete reference to %.*s, "
1170 		       "inode %lu parent %lu\n", name_len, name,
1171 		       inode->i_ino, dir->i_ino);
1172 		goto err;
1173 	}
1174 
1175 	di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
1176 					 index, name, name_len, -1);
1177 	if (IS_ERR(di)) {
1178 		ret = PTR_ERR(di);
1179 		goto err;
1180 	}
1181 	if (!di) {
1182 		ret = -ENOENT;
1183 		goto err;
1184 	}
1185 	ret = btrfs_delete_one_dir_name(trans, root, path, di);
1186 	btrfs_release_path(root, path);
1187 
1188 	ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
1189 					 inode, dir->i_ino);
1190 	BUG_ON(ret != 0 && ret != -ENOENT);
1191 	if (ret != -ENOENT)
1192 		BTRFS_I(dir)->log_dirty_trans = trans->transid;
1193 
1194 	ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
1195 					   dir, index);
1196 	BUG_ON(ret);
1197 err:
1198 	btrfs_free_path(path);
1199 	if (ret)
1200 		goto out;
1201 
1202 	btrfs_i_size_write(dir, dir->i_size - name_len * 2);
1203 	inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
1204 	btrfs_update_inode(trans, root, dir);
1205 	btrfs_drop_nlink(inode);
1206 	ret = btrfs_update_inode(trans, root, inode);
1207 	dir->i_sb->s_dirt = 1;
1208 out:
1209 	return ret;
1210 }
1211 
1212 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
1213 {
1214 	struct btrfs_root *root;
1215 	struct btrfs_trans_handle *trans;
1216 	struct inode *inode = dentry->d_inode;
1217 	int ret;
1218 	unsigned long nr = 0;
1219 
1220 	root = BTRFS_I(dir)->root;
1221 
1222 	ret = btrfs_check_free_space(root, 1, 1);
1223 	if (ret)
1224 		goto fail;
1225 
1226 	trans = btrfs_start_transaction(root, 1);
1227 
1228 	btrfs_set_trans_block_group(trans, dir);
1229 	ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
1230 				 dentry->d_name.name, dentry->d_name.len);
1231 
1232 	if (inode->i_nlink == 0)
1233 		ret = btrfs_orphan_add(trans, inode);
1234 
1235 	nr = trans->blocks_used;
1236 
1237 	btrfs_end_transaction_throttle(trans, root);
1238 fail:
1239 	btrfs_btree_balance_dirty(root, nr);
1240 	return ret;
1241 }
1242 
1243 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
1244 {
1245 	struct inode *inode = dentry->d_inode;
1246 	int err = 0;
1247 	int ret;
1248 	struct btrfs_root *root = BTRFS_I(dir)->root;
1249 	struct btrfs_trans_handle *trans;
1250 	unsigned long nr = 0;
1251 
1252 	if (inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
1253 		return -ENOTEMPTY;
1254 	}
1255 
1256 	ret = btrfs_check_free_space(root, 1, 1);
1257 	if (ret)
1258 		goto fail;
1259 
1260 	trans = btrfs_start_transaction(root, 1);
1261 	btrfs_set_trans_block_group(trans, dir);
1262 
1263 	err = btrfs_orphan_add(trans, inode);
1264 	if (err)
1265 		goto fail_trans;
1266 
1267 	/* now the directory is empty */
1268 	err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
1269 				 dentry->d_name.name, dentry->d_name.len);
1270 	if (!err) {
1271 		btrfs_i_size_write(inode, 0);
1272 	}
1273 
1274 fail_trans:
1275 	nr = trans->blocks_used;
1276 	ret = btrfs_end_transaction_throttle(trans, root);
1277 fail:
1278 	btrfs_btree_balance_dirty(root, nr);
1279 
1280 	if (ret && !err)
1281 		err = ret;
1282 	return err;
1283 }
1284 
1285 /*
1286  * this can truncate away extent items, csum items and directory items.
1287  * It starts at a high offset and removes keys until it can't find
1288  * any higher than i_size.
1289  *
1290  * csum items that cross the new i_size are truncated to the new size
1291  * as well.
1292  *
1293  * min_type is the minimum key type to truncate down to.  If set to 0, this
1294  * will kill all the items on this inode, including the INODE_ITEM_KEY.
1295  */
1296 noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
1297 					struct btrfs_root *root,
1298 					struct inode *inode,
1299 					u64 new_size, u32 min_type)
1300 {
1301 	int ret;
1302 	struct btrfs_path *path;
1303 	struct btrfs_key key;
1304 	struct btrfs_key found_key;
1305 	u32 found_type;
1306 	struct extent_buffer *leaf;
1307 	struct btrfs_file_extent_item *fi;
1308 	u64 extent_start = 0;
1309 	u64 extent_num_bytes = 0;
1310 	u64 item_end = 0;
1311 	u64 root_gen = 0;
1312 	u64 root_owner = 0;
1313 	int found_extent;
1314 	int del_item;
1315 	int pending_del_nr = 0;
1316 	int pending_del_slot = 0;
1317 	int extent_type = -1;
1318 	u64 mask = root->sectorsize - 1;
1319 
1320 	if (root->ref_cows)
1321 		btrfs_drop_extent_cache(inode,
1322 					new_size & (~mask), (u64)-1);
1323 	path = btrfs_alloc_path();
1324 	path->reada = -1;
1325 	BUG_ON(!path);
1326 
1327 	/* FIXME, add redo link to tree so we don't leak on crash */
1328 	key.objectid = inode->i_ino;
1329 	key.offset = (u64)-1;
1330 	key.type = (u8)-1;
1331 
1332 	btrfs_init_path(path);
1333 search_again:
1334 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1335 	if (ret < 0) {
1336 		goto error;
1337 	}
1338 	if (ret > 0) {
1339 		/* there are no items in the tree for us to truncate, we're
1340 		 * done
1341 		 */
1342 		if (path->slots[0] == 0) {
1343 			ret = 0;
1344 			goto error;
1345 		}
1346 		path->slots[0]--;
1347 	}
1348 
1349 	while(1) {
1350 		fi = NULL;
1351 		leaf = path->nodes[0];
1352 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1353 		found_type = btrfs_key_type(&found_key);
1354 
1355 		if (found_key.objectid != inode->i_ino)
1356 			break;
1357 
1358 		if (found_type < min_type)
1359 			break;
1360 
1361 		item_end = found_key.offset;
1362 		if (found_type == BTRFS_EXTENT_DATA_KEY) {
1363 			fi = btrfs_item_ptr(leaf, path->slots[0],
1364 					    struct btrfs_file_extent_item);
1365 			extent_type = btrfs_file_extent_type(leaf, fi);
1366 			if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
1367 				item_end +=
1368 				    btrfs_file_extent_num_bytes(leaf, fi);
1369 			} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1370 				struct btrfs_item *item = btrfs_item_nr(leaf,
1371 							        path->slots[0]);
1372 				item_end += btrfs_file_extent_inline_len(leaf,
1373 									 item);
1374 			}
1375 			item_end--;
1376 		}
1377 		if (found_type == BTRFS_CSUM_ITEM_KEY) {
1378 			ret = btrfs_csum_truncate(trans, root, path,
1379 						  new_size);
1380 			BUG_ON(ret);
1381 		}
1382 		if (item_end < new_size) {
1383 			if (found_type == BTRFS_DIR_ITEM_KEY) {
1384 				found_type = BTRFS_INODE_ITEM_KEY;
1385 			} else if (found_type == BTRFS_EXTENT_ITEM_KEY) {
1386 				found_type = BTRFS_CSUM_ITEM_KEY;
1387 			} else if (found_type == BTRFS_EXTENT_DATA_KEY) {
1388 				found_type = BTRFS_XATTR_ITEM_KEY;
1389 			} else if (found_type == BTRFS_XATTR_ITEM_KEY) {
1390 				found_type = BTRFS_INODE_REF_KEY;
1391 			} else if (found_type) {
1392 				found_type--;
1393 			} else {
1394 				break;
1395 			}
1396 			btrfs_set_key_type(&key, found_type);
1397 			goto next;
1398 		}
1399 		if (found_key.offset >= new_size)
1400 			del_item = 1;
1401 		else
1402 			del_item = 0;
1403 		found_extent = 0;
1404 
1405 		/* FIXME, shrink the extent if the ref count is only 1 */
1406 		if (found_type != BTRFS_EXTENT_DATA_KEY)
1407 			goto delete;
1408 
1409 		if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
1410 			u64 num_dec;
1411 			extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
1412 			if (!del_item) {
1413 				u64 orig_num_bytes =
1414 					btrfs_file_extent_num_bytes(leaf, fi);
1415 				extent_num_bytes = new_size -
1416 					found_key.offset + root->sectorsize - 1;
1417 				extent_num_bytes = extent_num_bytes &
1418 					~((u64)root->sectorsize - 1);
1419 				btrfs_set_file_extent_num_bytes(leaf, fi,
1420 							 extent_num_bytes);
1421 				num_dec = (orig_num_bytes -
1422 					   extent_num_bytes);
1423 				if (root->ref_cows && extent_start != 0)
1424 					dec_i_blocks(inode, num_dec);
1425 				btrfs_mark_buffer_dirty(leaf);
1426 			} else {
1427 				extent_num_bytes =
1428 					btrfs_file_extent_disk_num_bytes(leaf,
1429 									 fi);
1430 				/* FIXME blocksize != 4096 */
1431 				num_dec = btrfs_file_extent_num_bytes(leaf, fi);
1432 				if (extent_start != 0) {
1433 					found_extent = 1;
1434 					if (root->ref_cows)
1435 						dec_i_blocks(inode, num_dec);
1436 				}
1437 				if (root->ref_cows) {
1438 					root_gen =
1439 						btrfs_header_generation(leaf);
1440 				}
1441 				root_owner = btrfs_header_owner(leaf);
1442 			}
1443 		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1444 			if (!del_item) {
1445 				u32 size = new_size - found_key.offset;
1446 
1447 				if (root->ref_cows) {
1448 					dec_i_blocks(inode, item_end + 1 -
1449 						    found_key.offset - size);
1450 				}
1451 				size =
1452 				    btrfs_file_extent_calc_inline_size(size);
1453 				ret = btrfs_truncate_item(trans, root, path,
1454 							  size, 1);
1455 				BUG_ON(ret);
1456 			} else if (root->ref_cows) {
1457 				dec_i_blocks(inode, item_end + 1 -
1458 					     found_key.offset);
1459 			}
1460 		}
1461 delete:
1462 		if (del_item) {
1463 			if (!pending_del_nr) {
1464 				/* no pending yet, add ourselves */
1465 				pending_del_slot = path->slots[0];
1466 				pending_del_nr = 1;
1467 			} else if (pending_del_nr &&
1468 				   path->slots[0] + 1 == pending_del_slot) {
1469 				/* hop on the pending chunk */
1470 				pending_del_nr++;
1471 				pending_del_slot = path->slots[0];
1472 			} else {
1473 				printk("bad pending slot %d pending_del_nr %d pending_del_slot %d\n", path->slots[0], pending_del_nr, pending_del_slot);
1474 			}
1475 		} else {
1476 			break;
1477 		}
1478 		if (found_extent) {
1479 			ret = btrfs_free_extent(trans, root, extent_start,
1480 						extent_num_bytes,
1481 						root_owner,
1482 						root_gen, inode->i_ino,
1483 						found_key.offset, 0);
1484 			BUG_ON(ret);
1485 		}
1486 next:
1487 		if (path->slots[0] == 0) {
1488 			if (pending_del_nr)
1489 				goto del_pending;
1490 			btrfs_release_path(root, path);
1491 			goto search_again;
1492 		}
1493 
1494 		path->slots[0]--;
1495 		if (pending_del_nr &&
1496 		    path->slots[0] + 1 != pending_del_slot) {
1497 			struct btrfs_key debug;
1498 del_pending:
1499 			btrfs_item_key_to_cpu(path->nodes[0], &debug,
1500 					      pending_del_slot);
1501 			ret = btrfs_del_items(trans, root, path,
1502 					      pending_del_slot,
1503 					      pending_del_nr);
1504 			BUG_ON(ret);
1505 			pending_del_nr = 0;
1506 			btrfs_release_path(root, path);
1507 			goto search_again;
1508 		}
1509 	}
1510 	ret = 0;
1511 error:
1512 	if (pending_del_nr) {
1513 		ret = btrfs_del_items(trans, root, path, pending_del_slot,
1514 				      pending_del_nr);
1515 	}
1516 	btrfs_free_path(path);
1517 	inode->i_sb->s_dirt = 1;
1518 	return ret;
1519 }
1520 
1521 /*
1522  * taken from block_truncate_page, but does cow as it zeros out
1523  * any bytes left in the last page in the file.
1524  */
1525 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
1526 {
1527 	struct inode *inode = mapping->host;
1528 	struct btrfs_root *root = BTRFS_I(inode)->root;
1529 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1530 	struct btrfs_ordered_extent *ordered;
1531 	char *kaddr;
1532 	u32 blocksize = root->sectorsize;
1533 	pgoff_t index = from >> PAGE_CACHE_SHIFT;
1534 	unsigned offset = from & (PAGE_CACHE_SIZE-1);
1535 	struct page *page;
1536 	int ret = 0;
1537 	u64 page_start;
1538 	u64 page_end;
1539 
1540 	if ((offset & (blocksize - 1)) == 0)
1541 		goto out;
1542 
1543 	ret = -ENOMEM;
1544 again:
1545 	page = grab_cache_page(mapping, index);
1546 	if (!page)
1547 		goto out;
1548 
1549 	page_start = page_offset(page);
1550 	page_end = page_start + PAGE_CACHE_SIZE - 1;
1551 
1552 	if (!PageUptodate(page)) {
1553 		ret = btrfs_readpage(NULL, page);
1554 		lock_page(page);
1555 		if (page->mapping != mapping) {
1556 			unlock_page(page);
1557 			page_cache_release(page);
1558 			goto again;
1559 		}
1560 		if (!PageUptodate(page)) {
1561 			ret = -EIO;
1562 			goto out_unlock;
1563 		}
1564 	}
1565 	wait_on_page_writeback(page);
1566 
1567 	lock_extent(io_tree, page_start, page_end, GFP_NOFS);
1568 	set_page_extent_mapped(page);
1569 
1570 	ordered = btrfs_lookup_ordered_extent(inode, page_start);
1571 	if (ordered) {
1572 		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
1573 		unlock_page(page);
1574 		page_cache_release(page);
1575 		btrfs_start_ordered_extent(inode, ordered, 1);
1576 		btrfs_put_ordered_extent(ordered);
1577 		goto again;
1578 	}
1579 
1580 	btrfs_set_extent_delalloc(inode, page_start, page_end);
1581 	ret = 0;
1582 	if (offset != PAGE_CACHE_SIZE) {
1583 		kaddr = kmap(page);
1584 		memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
1585 		flush_dcache_page(page);
1586 		kunmap(page);
1587 	}
1588 	ClearPageChecked(page);
1589 	set_page_dirty(page);
1590 	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
1591 
1592 out_unlock:
1593 	unlock_page(page);
1594 	page_cache_release(page);
1595 out:
1596 	return ret;
1597 }
1598 
1599 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
1600 {
1601 	struct inode *inode = dentry->d_inode;
1602 	int err;
1603 
1604 	err = inode_change_ok(inode, attr);
1605 	if (err)
1606 		return err;
1607 
1608 	if (S_ISREG(inode->i_mode) &&
1609 	    attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
1610 		struct btrfs_trans_handle *trans;
1611 		struct btrfs_root *root = BTRFS_I(inode)->root;
1612 		struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1613 
1614 		u64 mask = root->sectorsize - 1;
1615 		u64 hole_start = (inode->i_size + mask) & ~mask;
1616 		u64 block_end = (attr->ia_size + mask) & ~mask;
1617 		u64 hole_size;
1618 		u64 alloc_hint = 0;
1619 
1620 		if (attr->ia_size <= hole_start)
1621 			goto out;
1622 
1623 		err = btrfs_check_free_space(root, 1, 0);
1624 		if (err)
1625 			goto fail;
1626 
1627 		btrfs_truncate_page(inode->i_mapping, inode->i_size);
1628 
1629 		hole_size = block_end - hole_start;
1630 		while(1) {
1631 			struct btrfs_ordered_extent *ordered;
1632 			btrfs_wait_ordered_range(inode, hole_start, hole_size);
1633 
1634 			lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
1635 			ordered = btrfs_lookup_ordered_extent(inode, hole_start);
1636 			if (ordered) {
1637 				unlock_extent(io_tree, hole_start,
1638 					      block_end - 1, GFP_NOFS);
1639 				btrfs_put_ordered_extent(ordered);
1640 			} else {
1641 				break;
1642 			}
1643 		}
1644 
1645 		trans = btrfs_start_transaction(root, 1);
1646 		btrfs_set_trans_block_group(trans, inode);
1647 		mutex_lock(&BTRFS_I(inode)->extent_mutex);
1648 		err = btrfs_drop_extents(trans, root, inode,
1649 					 hole_start, block_end, hole_start,
1650 					 &alloc_hint);
1651 
1652 		if (alloc_hint != EXTENT_MAP_INLINE) {
1653 			err = btrfs_insert_file_extent(trans, root,
1654 						       inode->i_ino,
1655 						       hole_start, 0, 0,
1656 						       hole_size, 0);
1657 			btrfs_drop_extent_cache(inode, hole_start,
1658 						(u64)-1);
1659 			btrfs_check_file(root, inode);
1660 		}
1661 		mutex_unlock(&BTRFS_I(inode)->extent_mutex);
1662 		btrfs_end_transaction(trans, root);
1663 		unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
1664 		if (err)
1665 			return err;
1666 	}
1667 out:
1668 	err = inode_setattr(inode, attr);
1669 
1670 	if (!err && ((attr->ia_valid & ATTR_MODE)))
1671 		err = btrfs_acl_chmod(inode);
1672 fail:
1673 	return err;
1674 }
1675 
1676 void btrfs_delete_inode(struct inode *inode)
1677 {
1678 	struct btrfs_trans_handle *trans;
1679 	struct btrfs_root *root = BTRFS_I(inode)->root;
1680 	unsigned long nr;
1681 	int ret;
1682 
1683 	truncate_inode_pages(&inode->i_data, 0);
1684 	if (is_bad_inode(inode)) {
1685 		btrfs_orphan_del(NULL, inode);
1686 		goto no_delete;
1687 	}
1688 	btrfs_wait_ordered_range(inode, 0, (u64)-1);
1689 
1690 	btrfs_i_size_write(inode, 0);
1691 	trans = btrfs_start_transaction(root, 1);
1692 
1693 	btrfs_set_trans_block_group(trans, inode);
1694 	ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size, 0);
1695 	if (ret) {
1696 		btrfs_orphan_del(NULL, inode);
1697 		goto no_delete_lock;
1698 	}
1699 
1700 	btrfs_orphan_del(trans, inode);
1701 
1702 	nr = trans->blocks_used;
1703 	clear_inode(inode);
1704 
1705 	btrfs_end_transaction(trans, root);
1706 	btrfs_btree_balance_dirty(root, nr);
1707 	return;
1708 
1709 no_delete_lock:
1710 	nr = trans->blocks_used;
1711 	btrfs_end_transaction(trans, root);
1712 	btrfs_btree_balance_dirty(root, nr);
1713 no_delete:
1714 	clear_inode(inode);
1715 }
1716 
1717 /*
1718  * this returns the key found in the dir entry in the location pointer.
1719  * If no dir entries were found, location->objectid is 0.
1720  */
1721 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
1722 			       struct btrfs_key *location)
1723 {
1724 	const char *name = dentry->d_name.name;
1725 	int namelen = dentry->d_name.len;
1726 	struct btrfs_dir_item *di;
1727 	struct btrfs_path *path;
1728 	struct btrfs_root *root = BTRFS_I(dir)->root;
1729 	int ret = 0;
1730 
1731 	path = btrfs_alloc_path();
1732 	BUG_ON(!path);
1733 
1734 	di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
1735 				    namelen, 0);
1736 	if (IS_ERR(di))
1737 		ret = PTR_ERR(di);
1738 	if (!di || IS_ERR(di)) {
1739 		goto out_err;
1740 	}
1741 	btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
1742 out:
1743 	btrfs_free_path(path);
1744 	return ret;
1745 out_err:
1746 	location->objectid = 0;
1747 	goto out;
1748 }
1749 
1750 /*
1751  * when we hit a tree root in a directory, the btrfs part of the inode
1752  * needs to be changed to reflect the root directory of the tree root.  This
1753  * is kind of like crossing a mount point.
1754  */
1755 static int fixup_tree_root_location(struct btrfs_root *root,
1756 			     struct btrfs_key *location,
1757 			     struct btrfs_root **sub_root,
1758 			     struct dentry *dentry)
1759 {
1760 	struct btrfs_root_item *ri;
1761 
1762 	if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
1763 		return 0;
1764 	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1765 		return 0;
1766 
1767 	*sub_root = btrfs_read_fs_root(root->fs_info, location,
1768 					dentry->d_name.name,
1769 					dentry->d_name.len);
1770 	if (IS_ERR(*sub_root))
1771 		return PTR_ERR(*sub_root);
1772 
1773 	ri = &(*sub_root)->root_item;
1774 	location->objectid = btrfs_root_dirid(ri);
1775 	btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
1776 	location->offset = 0;
1777 
1778 	return 0;
1779 }
1780 
1781 static noinline void init_btrfs_i(struct inode *inode)
1782 {
1783 	struct btrfs_inode *bi = BTRFS_I(inode);
1784 
1785 	bi->i_acl = NULL;
1786 	bi->i_default_acl = NULL;
1787 
1788 	bi->generation = 0;
1789 	bi->last_trans = 0;
1790 	bi->logged_trans = 0;
1791 	bi->delalloc_bytes = 0;
1792 	bi->disk_i_size = 0;
1793 	bi->flags = 0;
1794 	bi->index_cnt = (u64)-1;
1795 	bi->log_dirty_trans = 0;
1796 	extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
1797 	extent_io_tree_init(&BTRFS_I(inode)->io_tree,
1798 			     inode->i_mapping, GFP_NOFS);
1799 	extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
1800 			     inode->i_mapping, GFP_NOFS);
1801 	INIT_LIST_HEAD(&BTRFS_I(inode)->delalloc_inodes);
1802 	btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
1803 	mutex_init(&BTRFS_I(inode)->csum_mutex);
1804 	mutex_init(&BTRFS_I(inode)->extent_mutex);
1805 	mutex_init(&BTRFS_I(inode)->log_mutex);
1806 }
1807 
1808 static int btrfs_init_locked_inode(struct inode *inode, void *p)
1809 {
1810 	struct btrfs_iget_args *args = p;
1811 	inode->i_ino = args->ino;
1812 	init_btrfs_i(inode);
1813 	BTRFS_I(inode)->root = args->root;
1814 	return 0;
1815 }
1816 
1817 static int btrfs_find_actor(struct inode *inode, void *opaque)
1818 {
1819 	struct btrfs_iget_args *args = opaque;
1820 	return (args->ino == inode->i_ino &&
1821 		args->root == BTRFS_I(inode)->root);
1822 }
1823 
1824 struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
1825 				struct btrfs_root *root)
1826 {
1827 	struct inode *inode;
1828 	struct btrfs_iget_args args;
1829 	args.ino = objectid;
1830 	args.root = root;
1831 
1832 	inode = iget5_locked(s, objectid, btrfs_find_actor,
1833 			     btrfs_init_locked_inode,
1834 			     (void *)&args);
1835 	return inode;
1836 }
1837 
1838 /* Get an inode object given its location and corresponding root.
1839  * Returns in *is_new if the inode was read from disk
1840  */
1841 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
1842 			 struct btrfs_root *root, int *is_new)
1843 {
1844 	struct inode *inode;
1845 
1846 	inode = btrfs_iget_locked(s, location->objectid, root);
1847 	if (!inode)
1848 		return ERR_PTR(-EACCES);
1849 
1850 	if (inode->i_state & I_NEW) {
1851 		BTRFS_I(inode)->root = root;
1852 		memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
1853 		btrfs_read_locked_inode(inode);
1854 		unlock_new_inode(inode);
1855 		if (is_new)
1856 			*is_new = 1;
1857 	} else {
1858 		if (is_new)
1859 			*is_new = 0;
1860 	}
1861 
1862 	return inode;
1863 }
1864 
1865 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
1866 				   struct nameidata *nd)
1867 {
1868 	struct inode * inode;
1869 	struct btrfs_inode *bi = BTRFS_I(dir);
1870 	struct btrfs_root *root = bi->root;
1871 	struct btrfs_root *sub_root = root;
1872 	struct btrfs_key location;
1873 	int ret, new, do_orphan = 0;
1874 
1875 	if (dentry->d_name.len > BTRFS_NAME_LEN)
1876 		return ERR_PTR(-ENAMETOOLONG);
1877 
1878 	ret = btrfs_inode_by_name(dir, dentry, &location);
1879 
1880 	if (ret < 0)
1881 		return ERR_PTR(ret);
1882 
1883 	inode = NULL;
1884 	if (location.objectid) {
1885 		ret = fixup_tree_root_location(root, &location, &sub_root,
1886 						dentry);
1887 		if (ret < 0)
1888 			return ERR_PTR(ret);
1889 		if (ret > 0)
1890 			return ERR_PTR(-ENOENT);
1891 		inode = btrfs_iget(dir->i_sb, &location, sub_root, &new);
1892 		if (IS_ERR(inode))
1893 			return ERR_CAST(inode);
1894 
1895 		/* the inode and parent dir are two different roots */
1896 		if (new && root != sub_root) {
1897 			igrab(inode);
1898 			sub_root->inode = inode;
1899 			do_orphan = 1;
1900 		}
1901 	}
1902 
1903 	if (unlikely(do_orphan))
1904 		btrfs_orphan_cleanup(sub_root);
1905 
1906 	return d_splice_alias(inode, dentry);
1907 }
1908 
1909 static unsigned char btrfs_filetype_table[] = {
1910 	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
1911 };
1912 
1913 static int btrfs_real_readdir(struct file *filp, void *dirent,
1914 			      filldir_t filldir)
1915 {
1916 	struct inode *inode = filp->f_dentry->d_inode;
1917 	struct btrfs_root *root = BTRFS_I(inode)->root;
1918 	struct btrfs_item *item;
1919 	struct btrfs_dir_item *di;
1920 	struct btrfs_key key;
1921 	struct btrfs_key found_key;
1922 	struct btrfs_path *path;
1923 	int ret;
1924 	u32 nritems;
1925 	struct extent_buffer *leaf;
1926 	int slot;
1927 	int advance;
1928 	unsigned char d_type;
1929 	int over = 0;
1930 	u32 di_cur;
1931 	u32 di_total;
1932 	u32 di_len;
1933 	int key_type = BTRFS_DIR_INDEX_KEY;
1934 	char tmp_name[32];
1935 	char *name_ptr;
1936 	int name_len;
1937 
1938 	/* FIXME, use a real flag for deciding about the key type */
1939 	if (root->fs_info->tree_root == root)
1940 		key_type = BTRFS_DIR_ITEM_KEY;
1941 
1942 	/* special case for "." */
1943 	if (filp->f_pos == 0) {
1944 		over = filldir(dirent, ".", 1,
1945 			       1, inode->i_ino,
1946 			       DT_DIR);
1947 		if (over)
1948 			return 0;
1949 		filp->f_pos = 1;
1950 	}
1951 	/* special case for .., just use the back ref */
1952 	if (filp->f_pos == 1) {
1953 		u64 pino = parent_ino(filp->f_path.dentry);
1954 		over = filldir(dirent, "..", 2,
1955 			       2, pino, DT_DIR);
1956 		if (over)
1957 			return 0;
1958 		filp->f_pos = 2;
1959 	}
1960 
1961 	path = btrfs_alloc_path();
1962 	path->reada = 2;
1963 
1964 	btrfs_set_key_type(&key, key_type);
1965 	key.offset = filp->f_pos;
1966 	key.objectid = inode->i_ino;
1967 
1968 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1969 	if (ret < 0)
1970 		goto err;
1971 	advance = 0;
1972 
1973 	while (1) {
1974 		leaf = path->nodes[0];
1975 		nritems = btrfs_header_nritems(leaf);
1976 		slot = path->slots[0];
1977 		if (advance || slot >= nritems) {
1978 			if (slot >= nritems - 1) {
1979 				ret = btrfs_next_leaf(root, path);
1980 				if (ret)
1981 					break;
1982 				leaf = path->nodes[0];
1983 				nritems = btrfs_header_nritems(leaf);
1984 				slot = path->slots[0];
1985 			} else {
1986 				slot++;
1987 				path->slots[0]++;
1988 			}
1989 		}
1990 		advance = 1;
1991 		item = btrfs_item_nr(leaf, slot);
1992 		btrfs_item_key_to_cpu(leaf, &found_key, slot);
1993 
1994 		if (found_key.objectid != key.objectid)
1995 			break;
1996 		if (btrfs_key_type(&found_key) != key_type)
1997 			break;
1998 		if (found_key.offset < filp->f_pos)
1999 			continue;
2000 
2001 		filp->f_pos = found_key.offset;
2002 
2003 		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
2004 		di_cur = 0;
2005 		di_total = btrfs_item_size(leaf, item);
2006 
2007 		while (di_cur < di_total) {
2008 			struct btrfs_key location;
2009 
2010 			name_len = btrfs_dir_name_len(leaf, di);
2011 			if (name_len <= sizeof(tmp_name)) {
2012 				name_ptr = tmp_name;
2013 			} else {
2014 				name_ptr = kmalloc(name_len, GFP_NOFS);
2015 				if (!name_ptr) {
2016 					ret = -ENOMEM;
2017 					goto err;
2018 				}
2019 			}
2020 			read_extent_buffer(leaf, name_ptr,
2021 					   (unsigned long)(di + 1), name_len);
2022 
2023 			d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
2024 			btrfs_dir_item_key_to_cpu(leaf, di, &location);
2025 			over = filldir(dirent, name_ptr, name_len,
2026 				       found_key.offset, location.objectid,
2027 				       d_type);
2028 
2029 			if (name_ptr != tmp_name)
2030 				kfree(name_ptr);
2031 
2032 			if (over)
2033 				goto nopos;
2034 
2035 			di_len = btrfs_dir_name_len(leaf, di) +
2036 				 btrfs_dir_data_len(leaf, di) + sizeof(*di);
2037 			di_cur += di_len;
2038 			di = (struct btrfs_dir_item *)((char *)di + di_len);
2039 		}
2040 	}
2041 
2042 	/* Reached end of directory/root. Bump pos past the last item. */
2043 	if (key_type == BTRFS_DIR_INDEX_KEY)
2044 		filp->f_pos = INT_LIMIT(typeof(filp->f_pos));
2045 	else
2046 		filp->f_pos++;
2047 nopos:
2048 	ret = 0;
2049 err:
2050 	btrfs_free_path(path);
2051 	return ret;
2052 }
2053 
2054 /* Kernels earlier than 2.6.28 still have the NFS deadlock where nfsd
2055    will call the file system's ->lookup() method from within its
2056    filldir callback, which in turn was called from the file system's
2057    ->readdir() method. And will deadlock for many file systems. */
2058 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
2059 
2060 struct nfshack_dirent {
2061 	u64		ino;
2062 	loff_t		offset;
2063 	int		namlen;
2064 	unsigned int	d_type;
2065 	char		name[];
2066 };
2067 
2068 struct nfshack_readdir {
2069 	char		*dirent;
2070 	size_t		used;
2071 	int		full;
2072 };
2073 
2074 
2075 
2076 static int btrfs_nfshack_filldir(void *__buf, const char *name, int namlen,
2077 			      loff_t offset, u64 ino, unsigned int d_type)
2078 {
2079 	struct nfshack_readdir *buf = __buf;
2080 	struct nfshack_dirent *de = (void *)(buf->dirent + buf->used);
2081 	unsigned int reclen;
2082 
2083 	reclen = ALIGN(sizeof(struct nfshack_dirent) + namlen, sizeof(u64));
2084 	if (buf->used + reclen > PAGE_SIZE) {
2085 		buf->full = 1;
2086 		return -EINVAL;
2087 	}
2088 
2089 	de->namlen = namlen;
2090 	de->offset = offset;
2091 	de->ino = ino;
2092 	de->d_type = d_type;
2093 	memcpy(de->name, name, namlen);
2094 	buf->used += reclen;
2095 
2096 	return 0;
2097 }
2098 
2099 static int btrfs_nfshack_readdir(struct file *file, void *dirent,
2100 				 filldir_t filldir)
2101 {
2102 	struct nfshack_readdir buf;
2103 	struct nfshack_dirent *de;
2104 	int err;
2105 	int size;
2106 	loff_t offset;
2107 
2108 	buf.dirent = (void *)__get_free_page(GFP_KERNEL);
2109 	if (!buf.dirent)
2110 		return -ENOMEM;
2111 
2112 	offset = file->f_pos;
2113 
2114 	do {
2115 		unsigned int reclen;
2116 
2117 		buf.used = 0;
2118 		buf.full = 0;
2119 		err = btrfs_real_readdir(file, &buf, btrfs_nfshack_filldir);
2120 		if (err)
2121 			break;
2122 
2123 		size = buf.used;
2124 
2125 		if (!size)
2126 			break;
2127 
2128 		de = (struct nfshack_dirent *)buf.dirent;
2129 		while (size > 0) {
2130 			offset = de->offset;
2131 
2132 			if (filldir(dirent, de->name, de->namlen, de->offset,
2133 				    de->ino, de->d_type))
2134 				goto done;
2135 			offset = file->f_pos;
2136 
2137 			reclen = ALIGN(sizeof(*de) + de->namlen,
2138 				       sizeof(u64));
2139 			size -= reclen;
2140 			de = (struct nfshack_dirent *)((char *)de + reclen);
2141 		}
2142 	} while (buf.full);
2143 
2144  done:
2145 	free_page((unsigned long)buf.dirent);
2146 	file->f_pos = offset;
2147 
2148 	return err;
2149 }
2150 #endif
2151 
2152 int btrfs_write_inode(struct inode *inode, int wait)
2153 {
2154 	struct btrfs_root *root = BTRFS_I(inode)->root;
2155 	struct btrfs_trans_handle *trans;
2156 	int ret = 0;
2157 
2158 	if (root->fs_info->closing > 1)
2159 		return 0;
2160 
2161 	if (wait) {
2162 		trans = btrfs_join_transaction(root, 1);
2163 		btrfs_set_trans_block_group(trans, inode);
2164 		ret = btrfs_commit_transaction(trans, root);
2165 	}
2166 	return ret;
2167 }
2168 
2169 /*
2170  * This is somewhat expensive, updating the tree every time the
2171  * inode changes.  But, it is most likely to find the inode in cache.
2172  * FIXME, needs more benchmarking...there are no reasons other than performance
2173  * to keep or drop this code.
2174  */
2175 void btrfs_dirty_inode(struct inode *inode)
2176 {
2177 	struct btrfs_root *root = BTRFS_I(inode)->root;
2178 	struct btrfs_trans_handle *trans;
2179 
2180 	trans = btrfs_join_transaction(root, 1);
2181 	btrfs_set_trans_block_group(trans, inode);
2182 	btrfs_update_inode(trans, root, inode);
2183 	btrfs_end_transaction(trans, root);
2184 }
2185 
2186 static int btrfs_set_inode_index_count(struct inode *inode)
2187 {
2188 	struct btrfs_root *root = BTRFS_I(inode)->root;
2189 	struct btrfs_key key, found_key;
2190 	struct btrfs_path *path;
2191 	struct extent_buffer *leaf;
2192 	int ret;
2193 
2194 	key.objectid = inode->i_ino;
2195 	btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
2196 	key.offset = (u64)-1;
2197 
2198 	path = btrfs_alloc_path();
2199 	if (!path)
2200 		return -ENOMEM;
2201 
2202 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2203 	if (ret < 0)
2204 		goto out;
2205 	/* FIXME: we should be able to handle this */
2206 	if (ret == 0)
2207 		goto out;
2208 	ret = 0;
2209 
2210 	/*
2211 	 * MAGIC NUMBER EXPLANATION:
2212 	 * since we search a directory based on f_pos we have to start at 2
2213 	 * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
2214 	 * else has to start at 2
2215 	 */
2216 	if (path->slots[0] == 0) {
2217 		BTRFS_I(inode)->index_cnt = 2;
2218 		goto out;
2219 	}
2220 
2221 	path->slots[0]--;
2222 
2223 	leaf = path->nodes[0];
2224 	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2225 
2226 	if (found_key.objectid != inode->i_ino ||
2227 	    btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
2228 		BTRFS_I(inode)->index_cnt = 2;
2229 		goto out;
2230 	}
2231 
2232 	BTRFS_I(inode)->index_cnt = found_key.offset + 1;
2233 out:
2234 	btrfs_free_path(path);
2235 	return ret;
2236 }
2237 
2238 static int btrfs_set_inode_index(struct inode *dir, struct inode *inode,
2239 				 u64 *index)
2240 {
2241 	int ret = 0;
2242 
2243 	if (BTRFS_I(dir)->index_cnt == (u64)-1) {
2244 		ret = btrfs_set_inode_index_count(dir);
2245 		if (ret) {
2246 			return ret;
2247 		}
2248 	}
2249 
2250 	*index = BTRFS_I(dir)->index_cnt;
2251 	BTRFS_I(dir)->index_cnt++;
2252 
2253 	return ret;
2254 }
2255 
2256 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
2257 				     struct btrfs_root *root,
2258 				     struct inode *dir,
2259 				     const char *name, int name_len,
2260 				     u64 ref_objectid,
2261 				     u64 objectid,
2262 				     struct btrfs_block_group_cache *group,
2263 				     int mode, u64 *index)
2264 {
2265 	struct inode *inode;
2266 	struct btrfs_inode_item *inode_item;
2267 	struct btrfs_block_group_cache *new_inode_group;
2268 	struct btrfs_key *location;
2269 	struct btrfs_path *path;
2270 	struct btrfs_inode_ref *ref;
2271 	struct btrfs_key key[2];
2272 	u32 sizes[2];
2273 	unsigned long ptr;
2274 	int ret;
2275 	int owner;
2276 
2277 	path = btrfs_alloc_path();
2278 	BUG_ON(!path);
2279 
2280 	inode = new_inode(root->fs_info->sb);
2281 	if (!inode)
2282 		return ERR_PTR(-ENOMEM);
2283 
2284 	if (dir) {
2285 		ret = btrfs_set_inode_index(dir, inode, index);
2286 		if (ret)
2287 			return ERR_PTR(ret);
2288 	}
2289 	/*
2290 	 * index_cnt is ignored for everything but a dir,
2291 	 * btrfs_get_inode_index_count has an explanation for the magic
2292 	 * number
2293 	 */
2294 	init_btrfs_i(inode);
2295 	BTRFS_I(inode)->index_cnt = 2;
2296 	BTRFS_I(inode)->root = root;
2297 	BTRFS_I(inode)->generation = trans->transid;
2298 
2299 	if (mode & S_IFDIR)
2300 		owner = 0;
2301 	else
2302 		owner = 1;
2303 	new_inode_group = btrfs_find_block_group(root, group, 0,
2304 				       BTRFS_BLOCK_GROUP_METADATA, owner);
2305 	if (!new_inode_group) {
2306 		printk("find_block group failed\n");
2307 		new_inode_group = group;
2308 	}
2309 	BTRFS_I(inode)->block_group = new_inode_group;
2310 
2311 	key[0].objectid = objectid;
2312 	btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
2313 	key[0].offset = 0;
2314 
2315 	key[1].objectid = objectid;
2316 	btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
2317 	key[1].offset = ref_objectid;
2318 
2319 	sizes[0] = sizeof(struct btrfs_inode_item);
2320 	sizes[1] = name_len + sizeof(*ref);
2321 
2322 	ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
2323 	if (ret != 0)
2324 		goto fail;
2325 
2326 	if (objectid > root->highest_inode)
2327 		root->highest_inode = objectid;
2328 
2329 	inode->i_uid = current->fsuid;
2330 	inode->i_gid = current->fsgid;
2331 	inode->i_mode = mode;
2332 	inode->i_ino = objectid;
2333 	inode->i_blocks = 0;
2334 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2335 	inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2336 				  struct btrfs_inode_item);
2337 	fill_inode_item(trans, path->nodes[0], inode_item, inode);
2338 
2339 	ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2340 			     struct btrfs_inode_ref);
2341 	btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
2342 	btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
2343 	ptr = (unsigned long)(ref + 1);
2344 	write_extent_buffer(path->nodes[0], name, ptr, name_len);
2345 
2346 	btrfs_mark_buffer_dirty(path->nodes[0]);
2347 	btrfs_free_path(path);
2348 
2349 	location = &BTRFS_I(inode)->location;
2350 	location->objectid = objectid;
2351 	location->offset = 0;
2352 	btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
2353 
2354 	insert_inode_hash(inode);
2355 	return inode;
2356 fail:
2357 	if (dir)
2358 		BTRFS_I(dir)->index_cnt--;
2359 	btrfs_free_path(path);
2360 	return ERR_PTR(ret);
2361 }
2362 
2363 static inline u8 btrfs_inode_type(struct inode *inode)
2364 {
2365 	return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
2366 }
2367 
2368 int btrfs_add_link(struct btrfs_trans_handle *trans,
2369 		   struct inode *parent_inode, struct inode *inode,
2370 		   const char *name, int name_len, int add_backref, u64 index)
2371 {
2372 	int ret;
2373 	struct btrfs_key key;
2374 	struct btrfs_root *root = BTRFS_I(parent_inode)->root;
2375 
2376 	key.objectid = inode->i_ino;
2377 	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
2378 	key.offset = 0;
2379 
2380 	ret = btrfs_insert_dir_item(trans, root, name, name_len,
2381 				    parent_inode->i_ino,
2382 				    &key, btrfs_inode_type(inode),
2383 				    index);
2384 	if (ret == 0) {
2385 		if (add_backref) {
2386 			ret = btrfs_insert_inode_ref(trans, root,
2387 						     name, name_len,
2388 						     inode->i_ino,
2389 						     parent_inode->i_ino,
2390 						     index);
2391 		}
2392 		btrfs_i_size_write(parent_inode, parent_inode->i_size +
2393 				   name_len * 2);
2394 		parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
2395 		ret = btrfs_update_inode(trans, root, parent_inode);
2396 	}
2397 	return ret;
2398 }
2399 
2400 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
2401 			    struct dentry *dentry, struct inode *inode,
2402 			    int backref, u64 index)
2403 {
2404 	int err = btrfs_add_link(trans, dentry->d_parent->d_inode,
2405 				 inode, dentry->d_name.name,
2406 				 dentry->d_name.len, backref, index);
2407 	if (!err) {
2408 		d_instantiate(dentry, inode);
2409 		return 0;
2410 	}
2411 	if (err > 0)
2412 		err = -EEXIST;
2413 	return err;
2414 }
2415 
2416 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
2417 			int mode, dev_t rdev)
2418 {
2419 	struct btrfs_trans_handle *trans;
2420 	struct btrfs_root *root = BTRFS_I(dir)->root;
2421 	struct inode *inode = NULL;
2422 	int err;
2423 	int drop_inode = 0;
2424 	u64 objectid;
2425 	unsigned long nr = 0;
2426 	u64 index = 0;
2427 
2428 	if (!new_valid_dev(rdev))
2429 		return -EINVAL;
2430 
2431 	err = btrfs_check_free_space(root, 1, 0);
2432 	if (err)
2433 		goto fail;
2434 
2435 	trans = btrfs_start_transaction(root, 1);
2436 	btrfs_set_trans_block_group(trans, dir);
2437 
2438 	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
2439 	if (err) {
2440 		err = -ENOSPC;
2441 		goto out_unlock;
2442 	}
2443 
2444 	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
2445 				dentry->d_name.len,
2446 				dentry->d_parent->d_inode->i_ino, objectid,
2447 				BTRFS_I(dir)->block_group, mode, &index);
2448 	err = PTR_ERR(inode);
2449 	if (IS_ERR(inode))
2450 		goto out_unlock;
2451 
2452 	err = btrfs_init_acl(inode, dir);
2453 	if (err) {
2454 		drop_inode = 1;
2455 		goto out_unlock;
2456 	}
2457 
2458 	btrfs_set_trans_block_group(trans, inode);
2459 	err = btrfs_add_nondir(trans, dentry, inode, 0, index);
2460 	if (err)
2461 		drop_inode = 1;
2462 	else {
2463 		inode->i_op = &btrfs_special_inode_operations;
2464 		init_special_inode(inode, inode->i_mode, rdev);
2465 		btrfs_update_inode(trans, root, inode);
2466 	}
2467 	dir->i_sb->s_dirt = 1;
2468 	btrfs_update_inode_block_group(trans, inode);
2469 	btrfs_update_inode_block_group(trans, dir);
2470 out_unlock:
2471 	nr = trans->blocks_used;
2472 	btrfs_end_transaction_throttle(trans, root);
2473 fail:
2474 	if (drop_inode) {
2475 		inode_dec_link_count(inode);
2476 		iput(inode);
2477 	}
2478 	btrfs_btree_balance_dirty(root, nr);
2479 	return err;
2480 }
2481 
2482 static int btrfs_create(struct inode *dir, struct dentry *dentry,
2483 			int mode, struct nameidata *nd)
2484 {
2485 	struct btrfs_trans_handle *trans;
2486 	struct btrfs_root *root = BTRFS_I(dir)->root;
2487 	struct inode *inode = NULL;
2488 	int err;
2489 	int drop_inode = 0;
2490 	unsigned long nr = 0;
2491 	u64 objectid;
2492 	u64 index = 0;
2493 
2494 	err = btrfs_check_free_space(root, 1, 0);
2495 	if (err)
2496 		goto fail;
2497 	trans = btrfs_start_transaction(root, 1);
2498 	btrfs_set_trans_block_group(trans, dir);
2499 
2500 	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
2501 	if (err) {
2502 		err = -ENOSPC;
2503 		goto out_unlock;
2504 	}
2505 
2506 	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
2507 				dentry->d_name.len,
2508 				dentry->d_parent->d_inode->i_ino,
2509 				objectid, BTRFS_I(dir)->block_group, mode,
2510 				&index);
2511 	err = PTR_ERR(inode);
2512 	if (IS_ERR(inode))
2513 		goto out_unlock;
2514 
2515 	err = btrfs_init_acl(inode, dir);
2516 	if (err) {
2517 		drop_inode = 1;
2518 		goto out_unlock;
2519 	}
2520 
2521 	btrfs_set_trans_block_group(trans, inode);
2522 	err = btrfs_add_nondir(trans, dentry, inode, 0, index);
2523 	if (err)
2524 		drop_inode = 1;
2525 	else {
2526 		inode->i_mapping->a_ops = &btrfs_aops;
2527 		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2528 		inode->i_fop = &btrfs_file_operations;
2529 		inode->i_op = &btrfs_file_inode_operations;
2530 		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2531 	}
2532 	dir->i_sb->s_dirt = 1;
2533 	btrfs_update_inode_block_group(trans, inode);
2534 	btrfs_update_inode_block_group(trans, dir);
2535 out_unlock:
2536 	nr = trans->blocks_used;
2537 	btrfs_end_transaction_throttle(trans, root);
2538 fail:
2539 	if (drop_inode) {
2540 		inode_dec_link_count(inode);
2541 		iput(inode);
2542 	}
2543 	btrfs_btree_balance_dirty(root, nr);
2544 	return err;
2545 }
2546 
2547 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
2548 		      struct dentry *dentry)
2549 {
2550 	struct btrfs_trans_handle *trans;
2551 	struct btrfs_root *root = BTRFS_I(dir)->root;
2552 	struct inode *inode = old_dentry->d_inode;
2553 	u64 index;
2554 	unsigned long nr = 0;
2555 	int err;
2556 	int drop_inode = 0;
2557 
2558 	if (inode->i_nlink == 0)
2559 		return -ENOENT;
2560 
2561 	btrfs_inc_nlink(inode);
2562 	err = btrfs_check_free_space(root, 1, 0);
2563 	if (err)
2564 		goto fail;
2565 	err = btrfs_set_inode_index(dir, inode, &index);
2566 	if (err)
2567 		goto fail;
2568 
2569 	trans = btrfs_start_transaction(root, 1);
2570 
2571 	btrfs_set_trans_block_group(trans, dir);
2572 	atomic_inc(&inode->i_count);
2573 
2574 	err = btrfs_add_nondir(trans, dentry, inode, 1, index);
2575 
2576 	if (err)
2577 		drop_inode = 1;
2578 
2579 	dir->i_sb->s_dirt = 1;
2580 	btrfs_update_inode_block_group(trans, dir);
2581 	err = btrfs_update_inode(trans, root, inode);
2582 
2583 	if (err)
2584 		drop_inode = 1;
2585 
2586 	nr = trans->blocks_used;
2587 	btrfs_end_transaction_throttle(trans, root);
2588 fail:
2589 	if (drop_inode) {
2590 		inode_dec_link_count(inode);
2591 		iput(inode);
2592 	}
2593 	btrfs_btree_balance_dirty(root, nr);
2594 	return err;
2595 }
2596 
2597 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
2598 {
2599 	struct inode *inode = NULL;
2600 	struct btrfs_trans_handle *trans;
2601 	struct btrfs_root *root = BTRFS_I(dir)->root;
2602 	int err = 0;
2603 	int drop_on_err = 0;
2604 	u64 objectid = 0;
2605 	u64 index = 0;
2606 	unsigned long nr = 1;
2607 
2608 	err = btrfs_check_free_space(root, 1, 0);
2609 	if (err)
2610 		goto out_unlock;
2611 
2612 	trans = btrfs_start_transaction(root, 1);
2613 	btrfs_set_trans_block_group(trans, dir);
2614 
2615 	if (IS_ERR(trans)) {
2616 		err = PTR_ERR(trans);
2617 		goto out_unlock;
2618 	}
2619 
2620 	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
2621 	if (err) {
2622 		err = -ENOSPC;
2623 		goto out_unlock;
2624 	}
2625 
2626 	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
2627 				dentry->d_name.len,
2628 				dentry->d_parent->d_inode->i_ino, objectid,
2629 				BTRFS_I(dir)->block_group, S_IFDIR | mode,
2630 				&index);
2631 	if (IS_ERR(inode)) {
2632 		err = PTR_ERR(inode);
2633 		goto out_fail;
2634 	}
2635 
2636 	drop_on_err = 1;
2637 
2638 	err = btrfs_init_acl(inode, dir);
2639 	if (err)
2640 		goto out_fail;
2641 
2642 	inode->i_op = &btrfs_dir_inode_operations;
2643 	inode->i_fop = &btrfs_dir_file_operations;
2644 	btrfs_set_trans_block_group(trans, inode);
2645 
2646 	btrfs_i_size_write(inode, 0);
2647 	err = btrfs_update_inode(trans, root, inode);
2648 	if (err)
2649 		goto out_fail;
2650 
2651 	err = btrfs_add_link(trans, dentry->d_parent->d_inode,
2652 				 inode, dentry->d_name.name,
2653 				 dentry->d_name.len, 0, index);
2654 	if (err)
2655 		goto out_fail;
2656 
2657 	d_instantiate(dentry, inode);
2658 	drop_on_err = 0;
2659 	dir->i_sb->s_dirt = 1;
2660 	btrfs_update_inode_block_group(trans, inode);
2661 	btrfs_update_inode_block_group(trans, dir);
2662 
2663 out_fail:
2664 	nr = trans->blocks_used;
2665 	btrfs_end_transaction_throttle(trans, root);
2666 
2667 out_unlock:
2668 	if (drop_on_err)
2669 		iput(inode);
2670 	btrfs_btree_balance_dirty(root, nr);
2671 	return err;
2672 }
2673 
2674 static int merge_extent_mapping(struct extent_map_tree *em_tree,
2675 				struct extent_map *existing,
2676 				struct extent_map *em,
2677 				u64 map_start, u64 map_len)
2678 {
2679 	u64 start_diff;
2680 
2681 	BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
2682 	start_diff = map_start - em->start;
2683 	em->start = map_start;
2684 	em->len = map_len;
2685 	if (em->block_start < EXTENT_MAP_LAST_BYTE)
2686 		em->block_start += start_diff;
2687 	return add_extent_mapping(em_tree, em);
2688 }
2689 
2690 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
2691 				    size_t pg_offset, u64 start, u64 len,
2692 				    int create)
2693 {
2694 	int ret;
2695 	int err = 0;
2696 	u64 bytenr;
2697 	u64 extent_start = 0;
2698 	u64 extent_end = 0;
2699 	u64 objectid = inode->i_ino;
2700 	u32 found_type;
2701 	struct btrfs_path *path = NULL;
2702 	struct btrfs_root *root = BTRFS_I(inode)->root;
2703 	struct btrfs_file_extent_item *item;
2704 	struct extent_buffer *leaf;
2705 	struct btrfs_key found_key;
2706 	struct extent_map *em = NULL;
2707 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2708 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2709 	struct btrfs_trans_handle *trans = NULL;
2710 
2711 again:
2712 	spin_lock(&em_tree->lock);
2713 	em = lookup_extent_mapping(em_tree, start, len);
2714 	if (em)
2715 		em->bdev = root->fs_info->fs_devices->latest_bdev;
2716 	spin_unlock(&em_tree->lock);
2717 
2718 	if (em) {
2719 		if (em->start > start || em->start + em->len <= start)
2720 			free_extent_map(em);
2721 		else if (em->block_start == EXTENT_MAP_INLINE && page)
2722 			free_extent_map(em);
2723 		else
2724 			goto out;
2725 	}
2726 	em = alloc_extent_map(GFP_NOFS);
2727 	if (!em) {
2728 		err = -ENOMEM;
2729 		goto out;
2730 	}
2731 	em->bdev = root->fs_info->fs_devices->latest_bdev;
2732 	em->start = EXTENT_MAP_HOLE;
2733 	em->len = (u64)-1;
2734 
2735 	if (!path) {
2736 		path = btrfs_alloc_path();
2737 		BUG_ON(!path);
2738 	}
2739 
2740 	ret = btrfs_lookup_file_extent(trans, root, path,
2741 				       objectid, start, trans != NULL);
2742 	if (ret < 0) {
2743 		err = ret;
2744 		goto out;
2745 	}
2746 
2747 	if (ret != 0) {
2748 		if (path->slots[0] == 0)
2749 			goto not_found;
2750 		path->slots[0]--;
2751 	}
2752 
2753 	leaf = path->nodes[0];
2754 	item = btrfs_item_ptr(leaf, path->slots[0],
2755 			      struct btrfs_file_extent_item);
2756 	/* are we inside the extent that was found? */
2757 	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2758 	found_type = btrfs_key_type(&found_key);
2759 	if (found_key.objectid != objectid ||
2760 	    found_type != BTRFS_EXTENT_DATA_KEY) {
2761 		goto not_found;
2762 	}
2763 
2764 	found_type = btrfs_file_extent_type(leaf, item);
2765 	extent_start = found_key.offset;
2766 	if (found_type == BTRFS_FILE_EXTENT_REG) {
2767 		extent_end = extent_start +
2768 		       btrfs_file_extent_num_bytes(leaf, item);
2769 		err = 0;
2770 		if (start < extent_start || start >= extent_end) {
2771 			em->start = start;
2772 			if (start < extent_start) {
2773 				if (start + len <= extent_start)
2774 					goto not_found;
2775 				em->len = extent_end - extent_start;
2776 			} else {
2777 				em->len = len;
2778 			}
2779 			goto not_found_em;
2780 		}
2781 		bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
2782 		if (bytenr == 0) {
2783 			em->start = extent_start;
2784 			em->len = extent_end - extent_start;
2785 			em->block_start = EXTENT_MAP_HOLE;
2786 			goto insert;
2787 		}
2788 		bytenr += btrfs_file_extent_offset(leaf, item);
2789 		em->block_start = bytenr;
2790 		em->start = extent_start;
2791 		em->len = extent_end - extent_start;
2792 		goto insert;
2793 	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
2794 		u64 page_start;
2795 		unsigned long ptr;
2796 		char *map;
2797 		size_t size;
2798 		size_t extent_offset;
2799 		size_t copy_size;
2800 
2801 		size = btrfs_file_extent_inline_len(leaf, btrfs_item_nr(leaf,
2802 						    path->slots[0]));
2803 		extent_end = (extent_start + size + root->sectorsize - 1) &
2804 			~((u64)root->sectorsize - 1);
2805 		if (start < extent_start || start >= extent_end) {
2806 			em->start = start;
2807 			if (start < extent_start) {
2808 				if (start + len <= extent_start)
2809 					goto not_found;
2810 				em->len = extent_end - extent_start;
2811 			} else {
2812 				em->len = len;
2813 			}
2814 			goto not_found_em;
2815 		}
2816 		em->block_start = EXTENT_MAP_INLINE;
2817 
2818 		if (!page) {
2819 			em->start = extent_start;
2820 			em->len = size;
2821 			goto out;
2822 		}
2823 
2824 		page_start = page_offset(page) + pg_offset;
2825 		extent_offset = page_start - extent_start;
2826 		copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
2827 				size - extent_offset);
2828 		em->start = extent_start + extent_offset;
2829 		em->len = (copy_size + root->sectorsize - 1) &
2830 			~((u64)root->sectorsize - 1);
2831 		map = kmap(page);
2832 		ptr = btrfs_file_extent_inline_start(item) + extent_offset;
2833 		if (create == 0 && !PageUptodate(page)) {
2834 			read_extent_buffer(leaf, map + pg_offset, ptr,
2835 					   copy_size);
2836 			flush_dcache_page(page);
2837 		} else if (create && PageUptodate(page)) {
2838 			if (!trans) {
2839 				kunmap(page);
2840 				free_extent_map(em);
2841 				em = NULL;
2842 				btrfs_release_path(root, path);
2843 				trans = btrfs_join_transaction(root, 1);
2844 				goto again;
2845 			}
2846 			write_extent_buffer(leaf, map + pg_offset, ptr,
2847 					    copy_size);
2848 			btrfs_mark_buffer_dirty(leaf);
2849 		}
2850 		kunmap(page);
2851 		set_extent_uptodate(io_tree, em->start,
2852 				    extent_map_end(em) - 1, GFP_NOFS);
2853 		goto insert;
2854 	} else {
2855 		printk("unkknown found_type %d\n", found_type);
2856 		WARN_ON(1);
2857 	}
2858 not_found:
2859 	em->start = start;
2860 	em->len = len;
2861 not_found_em:
2862 	em->block_start = EXTENT_MAP_HOLE;
2863 insert:
2864 	btrfs_release_path(root, path);
2865 	if (em->start > start || extent_map_end(em) <= start) {
2866 		printk("bad extent! em: [%Lu %Lu] passed [%Lu %Lu]\n", em->start, em->len, start, len);
2867 		err = -EIO;
2868 		goto out;
2869 	}
2870 
2871 	err = 0;
2872 	spin_lock(&em_tree->lock);
2873 	ret = add_extent_mapping(em_tree, em);
2874 	/* it is possible that someone inserted the extent into the tree
2875 	 * while we had the lock dropped.  It is also possible that
2876 	 * an overlapping map exists in the tree
2877 	 */
2878 	if (ret == -EEXIST) {
2879 		struct extent_map *existing;
2880 
2881 		ret = 0;
2882 
2883 		existing = lookup_extent_mapping(em_tree, start, len);
2884 		if (existing && (existing->start > start ||
2885 		    existing->start + existing->len <= start)) {
2886 			free_extent_map(existing);
2887 			existing = NULL;
2888 		}
2889 		if (!existing) {
2890 			existing = lookup_extent_mapping(em_tree, em->start,
2891 							 em->len);
2892 			if (existing) {
2893 				err = merge_extent_mapping(em_tree, existing,
2894 							   em, start,
2895 							   root->sectorsize);
2896 				free_extent_map(existing);
2897 				if (err) {
2898 					free_extent_map(em);
2899 					em = NULL;
2900 				}
2901 			} else {
2902 				err = -EIO;
2903 				printk("failing to insert %Lu %Lu\n",
2904 				       start, len);
2905 				free_extent_map(em);
2906 				em = NULL;
2907 			}
2908 		} else {
2909 			free_extent_map(em);
2910 			em = existing;
2911 			err = 0;
2912 		}
2913 	}
2914 	spin_unlock(&em_tree->lock);
2915 out:
2916 	if (path)
2917 		btrfs_free_path(path);
2918 	if (trans) {
2919 		ret = btrfs_end_transaction(trans, root);
2920 		if (!err) {
2921 			err = ret;
2922 		}
2923 	}
2924 	if (err) {
2925 		free_extent_map(em);
2926 		WARN_ON(1);
2927 		return ERR_PTR(err);
2928 	}
2929 	return em;
2930 }
2931 
2932 #if 0 /* waiting for O_DIRECT reads */
2933 static int btrfs_get_block(struct inode *inode, sector_t iblock,
2934 			struct buffer_head *bh_result, int create)
2935 {
2936 	struct extent_map *em;
2937 	u64 start = (u64)iblock << inode->i_blkbits;
2938 	struct btrfs_multi_bio *multi = NULL;
2939 	struct btrfs_root *root = BTRFS_I(inode)->root;
2940 	u64 len;
2941 	u64 logical;
2942 	u64 map_length;
2943 	int ret = 0;
2944 
2945 	em = btrfs_get_extent(inode, NULL, 0, start, bh_result->b_size, 0);
2946 
2947 	if (!em || IS_ERR(em))
2948 		goto out;
2949 
2950 	if (em->start > start || em->start + em->len <= start) {
2951 	    goto out;
2952 	}
2953 
2954 	if (em->block_start == EXTENT_MAP_INLINE) {
2955 		ret = -EINVAL;
2956 		goto out;
2957 	}
2958 
2959 	len = em->start + em->len - start;
2960 	len = min_t(u64, len, INT_LIMIT(typeof(bh_result->b_size)));
2961 
2962 	if (em->block_start == EXTENT_MAP_HOLE ||
2963 	    em->block_start == EXTENT_MAP_DELALLOC) {
2964 		bh_result->b_size = len;
2965 		goto out;
2966 	}
2967 
2968 	logical = start - em->start;
2969 	logical = em->block_start + logical;
2970 
2971 	map_length = len;
2972 	ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
2973 			      logical, &map_length, &multi, 0);
2974 	BUG_ON(ret);
2975 	bh_result->b_blocknr = multi->stripes[0].physical >> inode->i_blkbits;
2976 	bh_result->b_size = min(map_length, len);
2977 
2978 	bh_result->b_bdev = multi->stripes[0].dev->bdev;
2979 	set_buffer_mapped(bh_result);
2980 	kfree(multi);
2981 out:
2982 	free_extent_map(em);
2983 	return ret;
2984 }
2985 #endif
2986 
2987 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
2988 			const struct iovec *iov, loff_t offset,
2989 			unsigned long nr_segs)
2990 {
2991 	return -EINVAL;
2992 #if 0
2993 	struct file *file = iocb->ki_filp;
2994 	struct inode *inode = file->f_mapping->host;
2995 
2996 	if (rw == WRITE)
2997 		return -EINVAL;
2998 
2999 	return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
3000 				  offset, nr_segs, btrfs_get_block, NULL);
3001 #endif
3002 }
3003 
3004 static sector_t btrfs_bmap(struct address_space *mapping, sector_t iblock)
3005 {
3006 	return extent_bmap(mapping, iblock, btrfs_get_extent);
3007 }
3008 
3009 int btrfs_readpage(struct file *file, struct page *page)
3010 {
3011 	struct extent_io_tree *tree;
3012 	tree = &BTRFS_I(page->mapping->host)->io_tree;
3013 	return extent_read_full_page(tree, page, btrfs_get_extent);
3014 }
3015 
3016 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
3017 {
3018 	struct extent_io_tree *tree;
3019 
3020 
3021 	if (current->flags & PF_MEMALLOC) {
3022 		redirty_page_for_writepage(wbc, page);
3023 		unlock_page(page);
3024 		return 0;
3025 	}
3026 	tree = &BTRFS_I(page->mapping->host)->io_tree;
3027 	return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
3028 }
3029 
3030 int btrfs_writepages(struct address_space *mapping,
3031 		     struct writeback_control *wbc)
3032 {
3033 	struct extent_io_tree *tree;
3034 	tree = &BTRFS_I(mapping->host)->io_tree;
3035 	return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
3036 }
3037 
3038 static int
3039 btrfs_readpages(struct file *file, struct address_space *mapping,
3040 		struct list_head *pages, unsigned nr_pages)
3041 {
3042 	struct extent_io_tree *tree;
3043 	tree = &BTRFS_I(mapping->host)->io_tree;
3044 	return extent_readpages(tree, mapping, pages, nr_pages,
3045 				btrfs_get_extent);
3046 }
3047 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
3048 {
3049 	struct extent_io_tree *tree;
3050 	struct extent_map_tree *map;
3051 	int ret;
3052 
3053 	tree = &BTRFS_I(page->mapping->host)->io_tree;
3054 	map = &BTRFS_I(page->mapping->host)->extent_tree;
3055 	ret = try_release_extent_mapping(map, tree, page, gfp_flags);
3056 	if (ret == 1) {
3057 		ClearPagePrivate(page);
3058 		set_page_private(page, 0);
3059 		page_cache_release(page);
3060 	}
3061 	return ret;
3062 }
3063 
3064 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
3065 {
3066 	if (PageWriteback(page) || PageDirty(page))
3067 		return 0;
3068 	return __btrfs_releasepage(page, gfp_flags);
3069 }
3070 
3071 static void btrfs_invalidatepage(struct page *page, unsigned long offset)
3072 {
3073 	struct extent_io_tree *tree;
3074 	struct btrfs_ordered_extent *ordered;
3075 	u64 page_start = page_offset(page);
3076 	u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
3077 
3078 	wait_on_page_writeback(page);
3079 	tree = &BTRFS_I(page->mapping->host)->io_tree;
3080 	if (offset) {
3081 		btrfs_releasepage(page, GFP_NOFS);
3082 		return;
3083 	}
3084 
3085 	lock_extent(tree, page_start, page_end, GFP_NOFS);
3086 	ordered = btrfs_lookup_ordered_extent(page->mapping->host,
3087 					   page_offset(page));
3088 	if (ordered) {
3089 		/*
3090 		 * IO on this page will never be started, so we need
3091 		 * to account for any ordered extents now
3092 		 */
3093 		clear_extent_bit(tree, page_start, page_end,
3094 				 EXTENT_DIRTY | EXTENT_DELALLOC |
3095 				 EXTENT_LOCKED, 1, 0, GFP_NOFS);
3096 		btrfs_finish_ordered_io(page->mapping->host,
3097 					page_start, page_end);
3098 		btrfs_put_ordered_extent(ordered);
3099 		lock_extent(tree, page_start, page_end, GFP_NOFS);
3100 	}
3101 	clear_extent_bit(tree, page_start, page_end,
3102 		 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
3103 		 EXTENT_ORDERED,
3104 		 1, 1, GFP_NOFS);
3105 	__btrfs_releasepage(page, GFP_NOFS);
3106 
3107 	ClearPageChecked(page);
3108 	if (PagePrivate(page)) {
3109 		ClearPagePrivate(page);
3110 		set_page_private(page, 0);
3111 		page_cache_release(page);
3112 	}
3113 }
3114 
3115 /*
3116  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
3117  * called from a page fault handler when a page is first dirtied. Hence we must
3118  * be careful to check for EOF conditions here. We set the page up correctly
3119  * for a written page which means we get ENOSPC checking when writing into
3120  * holes and correct delalloc and unwritten extent mapping on filesystems that
3121  * support these features.
3122  *
3123  * We are not allowed to take the i_mutex here so we have to play games to
3124  * protect against truncate races as the page could now be beyond EOF.  Because
3125  * vmtruncate() writes the inode size before removing pages, once we have the
3126  * page lock we can determine safely if the page is beyond EOF. If it is not
3127  * beyond EOF, then the page is guaranteed safe against truncation until we
3128  * unlock the page.
3129  */
3130 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
3131 {
3132 	struct inode *inode = fdentry(vma->vm_file)->d_inode;
3133 	struct btrfs_root *root = BTRFS_I(inode)->root;
3134 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3135 	struct btrfs_ordered_extent *ordered;
3136 	char *kaddr;
3137 	unsigned long zero_start;
3138 	loff_t size;
3139 	int ret;
3140 	u64 page_start;
3141 	u64 page_end;
3142 
3143 	ret = btrfs_check_free_space(root, PAGE_CACHE_SIZE, 0);
3144 	if (ret)
3145 		goto out;
3146 
3147 	ret = -EINVAL;
3148 again:
3149 	lock_page(page);
3150 	size = i_size_read(inode);
3151 	page_start = page_offset(page);
3152 	page_end = page_start + PAGE_CACHE_SIZE - 1;
3153 
3154 	if ((page->mapping != inode->i_mapping) ||
3155 	    (page_start >= size)) {
3156 		/* page got truncated out from underneath us */
3157 		goto out_unlock;
3158 	}
3159 	wait_on_page_writeback(page);
3160 
3161 	lock_extent(io_tree, page_start, page_end, GFP_NOFS);
3162 	set_page_extent_mapped(page);
3163 
3164 	/*
3165 	 * we can't set the delalloc bits if there are pending ordered
3166 	 * extents.  Drop our locks and wait for them to finish
3167 	 */
3168 	ordered = btrfs_lookup_ordered_extent(inode, page_start);
3169 	if (ordered) {
3170 		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3171 		unlock_page(page);
3172 		btrfs_start_ordered_extent(inode, ordered, 1);
3173 		btrfs_put_ordered_extent(ordered);
3174 		goto again;
3175 	}
3176 
3177 	btrfs_set_extent_delalloc(inode, page_start, page_end);
3178 	ret = 0;
3179 
3180 	/* page is wholly or partially inside EOF */
3181 	if (page_start + PAGE_CACHE_SIZE > size)
3182 		zero_start = size & ~PAGE_CACHE_MASK;
3183 	else
3184 		zero_start = PAGE_CACHE_SIZE;
3185 
3186 	if (zero_start != PAGE_CACHE_SIZE) {
3187 		kaddr = kmap(page);
3188 		memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
3189 		flush_dcache_page(page);
3190 		kunmap(page);
3191 	}
3192 	ClearPageChecked(page);
3193 	set_page_dirty(page);
3194 	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3195 
3196 out_unlock:
3197 	unlock_page(page);
3198 out:
3199 	return ret;
3200 }
3201 
3202 static void btrfs_truncate(struct inode *inode)
3203 {
3204 	struct btrfs_root *root = BTRFS_I(inode)->root;
3205 	int ret;
3206 	struct btrfs_trans_handle *trans;
3207 	unsigned long nr;
3208 	u64 mask = root->sectorsize - 1;
3209 
3210 	if (!S_ISREG(inode->i_mode))
3211 		return;
3212 	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
3213 		return;
3214 
3215 	btrfs_truncate_page(inode->i_mapping, inode->i_size);
3216 	btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
3217 
3218 	trans = btrfs_start_transaction(root, 1);
3219 	btrfs_set_trans_block_group(trans, inode);
3220 	btrfs_i_size_write(inode, inode->i_size);
3221 
3222 	ret = btrfs_orphan_add(trans, inode);
3223 	if (ret)
3224 		goto out;
3225 	/* FIXME, add redo link to tree so we don't leak on crash */
3226 	ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size,
3227 				      BTRFS_EXTENT_DATA_KEY);
3228 	btrfs_update_inode(trans, root, inode);
3229 
3230 	ret = btrfs_orphan_del(trans, inode);
3231 	BUG_ON(ret);
3232 
3233 out:
3234 	nr = trans->blocks_used;
3235 	ret = btrfs_end_transaction_throttle(trans, root);
3236 	BUG_ON(ret);
3237 	btrfs_btree_balance_dirty(root, nr);
3238 }
3239 
3240 /*
3241  * Invalidate a single dcache entry at the root of the filesystem.
3242  * Needed after creation of snapshot or subvolume.
3243  */
3244 void btrfs_invalidate_dcache_root(struct btrfs_root *root, char *name,
3245 				  int namelen)
3246 {
3247 	struct dentry *alias, *entry;
3248 	struct qstr qstr;
3249 
3250 	alias = d_find_alias(root->fs_info->sb->s_root->d_inode);
3251 	if (alias) {
3252 		qstr.name = name;
3253 		qstr.len = namelen;
3254 		/* change me if btrfs ever gets a d_hash operation */
3255 		qstr.hash = full_name_hash(qstr.name, qstr.len);
3256 		entry = d_lookup(alias, &qstr);
3257 		dput(alias);
3258 		if (entry) {
3259 			d_invalidate(entry);
3260 			dput(entry);
3261 		}
3262 	}
3263 }
3264 
3265 int btrfs_create_subvol_root(struct btrfs_root *new_root,
3266 		struct btrfs_trans_handle *trans, u64 new_dirid,
3267 		struct btrfs_block_group_cache *block_group)
3268 {
3269 	struct inode *inode;
3270 	u64 index = 0;
3271 
3272 	inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
3273 				new_dirid, block_group, S_IFDIR | 0700, &index);
3274 	if (IS_ERR(inode))
3275 		return PTR_ERR(inode);
3276 	inode->i_op = &btrfs_dir_inode_operations;
3277 	inode->i_fop = &btrfs_dir_file_operations;
3278 	new_root->inode = inode;
3279 
3280 	inode->i_nlink = 1;
3281 	btrfs_i_size_write(inode, 0);
3282 
3283 	return btrfs_update_inode(trans, new_root, inode);
3284 }
3285 
3286 unsigned long btrfs_force_ra(struct address_space *mapping,
3287 			      struct file_ra_state *ra, struct file *file,
3288 			      pgoff_t offset, pgoff_t last_index)
3289 {
3290 	pgoff_t req_size = last_index - offset + 1;
3291 
3292 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
3293 	offset = page_cache_readahead(mapping, ra, file, offset, req_size);
3294 	return offset;
3295 #else
3296 	page_cache_sync_readahead(mapping, ra, file, offset, req_size);
3297 	return offset + req_size;
3298 #endif
3299 }
3300 
3301 struct inode *btrfs_alloc_inode(struct super_block *sb)
3302 {
3303 	struct btrfs_inode *ei;
3304 
3305 	ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
3306 	if (!ei)
3307 		return NULL;
3308 	ei->last_trans = 0;
3309 	ei->logged_trans = 0;
3310 	btrfs_ordered_inode_tree_init(&ei->ordered_tree);
3311 	ei->i_acl = BTRFS_ACL_NOT_CACHED;
3312 	ei->i_default_acl = BTRFS_ACL_NOT_CACHED;
3313 	INIT_LIST_HEAD(&ei->i_orphan);
3314 	return &ei->vfs_inode;
3315 }
3316 
3317 void btrfs_destroy_inode(struct inode *inode)
3318 {
3319 	struct btrfs_ordered_extent *ordered;
3320 	WARN_ON(!list_empty(&inode->i_dentry));
3321 	WARN_ON(inode->i_data.nrpages);
3322 
3323 	if (BTRFS_I(inode)->i_acl &&
3324 	    BTRFS_I(inode)->i_acl != BTRFS_ACL_NOT_CACHED)
3325 		posix_acl_release(BTRFS_I(inode)->i_acl);
3326 	if (BTRFS_I(inode)->i_default_acl &&
3327 	    BTRFS_I(inode)->i_default_acl != BTRFS_ACL_NOT_CACHED)
3328 		posix_acl_release(BTRFS_I(inode)->i_default_acl);
3329 
3330 	spin_lock(&BTRFS_I(inode)->root->list_lock);
3331 	if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
3332 		printk(KERN_ERR "BTRFS: inode %lu: inode still on the orphan"
3333 		       " list\n", inode->i_ino);
3334 		dump_stack();
3335 	}
3336 	spin_unlock(&BTRFS_I(inode)->root->list_lock);
3337 
3338 	while(1) {
3339 		ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
3340 		if (!ordered)
3341 			break;
3342 		else {
3343 			printk("found ordered extent %Lu %Lu\n",
3344 			       ordered->file_offset, ordered->len);
3345 			btrfs_remove_ordered_extent(inode, ordered);
3346 			btrfs_put_ordered_extent(ordered);
3347 			btrfs_put_ordered_extent(ordered);
3348 		}
3349 	}
3350 	btrfs_drop_extent_cache(inode, 0, (u64)-1);
3351 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
3352 }
3353 
3354 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
3355 static void init_once(void *foo)
3356 #elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
3357 static void init_once(struct kmem_cache * cachep, void *foo)
3358 #else
3359 static void init_once(void * foo, struct kmem_cache * cachep,
3360 		      unsigned long flags)
3361 #endif
3362 {
3363 	struct btrfs_inode *ei = (struct btrfs_inode *) foo;
3364 
3365 	inode_init_once(&ei->vfs_inode);
3366 }
3367 
3368 void btrfs_destroy_cachep(void)
3369 {
3370 	if (btrfs_inode_cachep)
3371 		kmem_cache_destroy(btrfs_inode_cachep);
3372 	if (btrfs_trans_handle_cachep)
3373 		kmem_cache_destroy(btrfs_trans_handle_cachep);
3374 	if (btrfs_transaction_cachep)
3375 		kmem_cache_destroy(btrfs_transaction_cachep);
3376 	if (btrfs_bit_radix_cachep)
3377 		kmem_cache_destroy(btrfs_bit_radix_cachep);
3378 	if (btrfs_path_cachep)
3379 		kmem_cache_destroy(btrfs_path_cachep);
3380 }
3381 
3382 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
3383 				       unsigned long extra_flags,
3384 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
3385 				       void (*ctor)(void *)
3386 #elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
3387 				       void (*ctor)(struct kmem_cache *, void *)
3388 #else
3389 				       void (*ctor)(void *, struct kmem_cache *,
3390 						    unsigned long)
3391 #endif
3392 				     )
3393 {
3394 	return kmem_cache_create(name, size, 0, (SLAB_RECLAIM_ACCOUNT |
3395 				 SLAB_MEM_SPREAD | extra_flags), ctor
3396 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
3397 				 ,NULL
3398 #endif
3399 				);
3400 }
3401 
3402 int btrfs_init_cachep(void)
3403 {
3404 	btrfs_inode_cachep = btrfs_cache_create("btrfs_inode_cache",
3405 					  sizeof(struct btrfs_inode),
3406 					  0, init_once);
3407 	if (!btrfs_inode_cachep)
3408 		goto fail;
3409 	btrfs_trans_handle_cachep =
3410 			btrfs_cache_create("btrfs_trans_handle_cache",
3411 					   sizeof(struct btrfs_trans_handle),
3412 					   0, NULL);
3413 	if (!btrfs_trans_handle_cachep)
3414 		goto fail;
3415 	btrfs_transaction_cachep = btrfs_cache_create("btrfs_transaction_cache",
3416 					     sizeof(struct btrfs_transaction),
3417 					     0, NULL);
3418 	if (!btrfs_transaction_cachep)
3419 		goto fail;
3420 	btrfs_path_cachep = btrfs_cache_create("btrfs_path_cache",
3421 					 sizeof(struct btrfs_path),
3422 					 0, NULL);
3423 	if (!btrfs_path_cachep)
3424 		goto fail;
3425 	btrfs_bit_radix_cachep = btrfs_cache_create("btrfs_radix", 256,
3426 					      SLAB_DESTROY_BY_RCU, NULL);
3427 	if (!btrfs_bit_radix_cachep)
3428 		goto fail;
3429 	return 0;
3430 fail:
3431 	btrfs_destroy_cachep();
3432 	return -ENOMEM;
3433 }
3434 
3435 static int btrfs_getattr(struct vfsmount *mnt,
3436 			 struct dentry *dentry, struct kstat *stat)
3437 {
3438 	struct inode *inode = dentry->d_inode;
3439 	generic_fillattr(inode, stat);
3440 	stat->blksize = PAGE_CACHE_SIZE;
3441 	stat->blocks = inode->i_blocks + (BTRFS_I(inode)->delalloc_bytes >> 9);
3442 	return 0;
3443 }
3444 
3445 static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
3446 			   struct inode * new_dir,struct dentry *new_dentry)
3447 {
3448 	struct btrfs_trans_handle *trans;
3449 	struct btrfs_root *root = BTRFS_I(old_dir)->root;
3450 	struct inode *new_inode = new_dentry->d_inode;
3451 	struct inode *old_inode = old_dentry->d_inode;
3452 	struct timespec ctime = CURRENT_TIME;
3453 	u64 index = 0;
3454 	int ret;
3455 
3456 	if (S_ISDIR(old_inode->i_mode) && new_inode &&
3457 	    new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
3458 		return -ENOTEMPTY;
3459 	}
3460 
3461 	ret = btrfs_check_free_space(root, 1, 0);
3462 	if (ret)
3463 		goto out_unlock;
3464 
3465 	trans = btrfs_start_transaction(root, 1);
3466 
3467 	btrfs_set_trans_block_group(trans, new_dir);
3468 
3469 	btrfs_inc_nlink(old_dentry->d_inode);
3470 	old_dir->i_ctime = old_dir->i_mtime = ctime;
3471 	new_dir->i_ctime = new_dir->i_mtime = ctime;
3472 	old_inode->i_ctime = ctime;
3473 
3474 	ret = btrfs_unlink_inode(trans, root, old_dir, old_dentry->d_inode,
3475 				 old_dentry->d_name.name,
3476 				 old_dentry->d_name.len);
3477 	if (ret)
3478 		goto out_fail;
3479 
3480 	if (new_inode) {
3481 		new_inode->i_ctime = CURRENT_TIME;
3482 		ret = btrfs_unlink_inode(trans, root, new_dir,
3483 					 new_dentry->d_inode,
3484 					 new_dentry->d_name.name,
3485 					 new_dentry->d_name.len);
3486 		if (ret)
3487 			goto out_fail;
3488 		if (new_inode->i_nlink == 0) {
3489 			ret = btrfs_orphan_add(trans, new_dentry->d_inode);
3490 			if (ret)
3491 				goto out_fail;
3492 		}
3493 
3494 	}
3495 	ret = btrfs_set_inode_index(new_dir, old_inode, &index);
3496 	if (ret)
3497 		goto out_fail;
3498 
3499 	ret = btrfs_add_link(trans, new_dentry->d_parent->d_inode,
3500 			     old_inode, new_dentry->d_name.name,
3501 			     new_dentry->d_name.len, 1, index);
3502 	if (ret)
3503 		goto out_fail;
3504 
3505 out_fail:
3506 	btrfs_end_transaction_throttle(trans, root);
3507 out_unlock:
3508 	return ret;
3509 }
3510 
3511 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
3512 {
3513 	struct list_head *head = &root->fs_info->delalloc_inodes;
3514 	struct btrfs_inode *binode;
3515 	unsigned long flags;
3516 
3517 	spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
3518 	while(!list_empty(head)) {
3519 		binode = list_entry(head->next, struct btrfs_inode,
3520 				    delalloc_inodes);
3521 		atomic_inc(&binode->vfs_inode.i_count);
3522 		spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);
3523 		filemap_write_and_wait(binode->vfs_inode.i_mapping);
3524 		iput(&binode->vfs_inode);
3525 		spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
3526 	}
3527 	spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);
3528 	return 0;
3529 }
3530 
3531 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
3532 			 const char *symname)
3533 {
3534 	struct btrfs_trans_handle *trans;
3535 	struct btrfs_root *root = BTRFS_I(dir)->root;
3536 	struct btrfs_path *path;
3537 	struct btrfs_key key;
3538 	struct inode *inode = NULL;
3539 	int err;
3540 	int drop_inode = 0;
3541 	u64 objectid;
3542 	u64 index = 0 ;
3543 	int name_len;
3544 	int datasize;
3545 	unsigned long ptr;
3546 	struct btrfs_file_extent_item *ei;
3547 	struct extent_buffer *leaf;
3548 	unsigned long nr = 0;
3549 
3550 	name_len = strlen(symname) + 1;
3551 	if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
3552 		return -ENAMETOOLONG;
3553 
3554 	err = btrfs_check_free_space(root, 1, 0);
3555 	if (err)
3556 		goto out_fail;
3557 
3558 	trans = btrfs_start_transaction(root, 1);
3559 	btrfs_set_trans_block_group(trans, dir);
3560 
3561 	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
3562 	if (err) {
3563 		err = -ENOSPC;
3564 		goto out_unlock;
3565 	}
3566 
3567 	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
3568 				dentry->d_name.len,
3569 				dentry->d_parent->d_inode->i_ino, objectid,
3570 				BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
3571 				&index);
3572 	err = PTR_ERR(inode);
3573 	if (IS_ERR(inode))
3574 		goto out_unlock;
3575 
3576 	err = btrfs_init_acl(inode, dir);
3577 	if (err) {
3578 		drop_inode = 1;
3579 		goto out_unlock;
3580 	}
3581 
3582 	btrfs_set_trans_block_group(trans, inode);
3583 	err = btrfs_add_nondir(trans, dentry, inode, 0, index);
3584 	if (err)
3585 		drop_inode = 1;
3586 	else {
3587 		inode->i_mapping->a_ops = &btrfs_aops;
3588 		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3589 		inode->i_fop = &btrfs_file_operations;
3590 		inode->i_op = &btrfs_file_inode_operations;
3591 		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3592 	}
3593 	dir->i_sb->s_dirt = 1;
3594 	btrfs_update_inode_block_group(trans, inode);
3595 	btrfs_update_inode_block_group(trans, dir);
3596 	if (drop_inode)
3597 		goto out_unlock;
3598 
3599 	path = btrfs_alloc_path();
3600 	BUG_ON(!path);
3601 	key.objectid = inode->i_ino;
3602 	key.offset = 0;
3603 	btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
3604 	datasize = btrfs_file_extent_calc_inline_size(name_len);
3605 	err = btrfs_insert_empty_item(trans, root, path, &key,
3606 				      datasize);
3607 	if (err) {
3608 		drop_inode = 1;
3609 		goto out_unlock;
3610 	}
3611 	leaf = path->nodes[0];
3612 	ei = btrfs_item_ptr(leaf, path->slots[0],
3613 			    struct btrfs_file_extent_item);
3614 	btrfs_set_file_extent_generation(leaf, ei, trans->transid);
3615 	btrfs_set_file_extent_type(leaf, ei,
3616 				   BTRFS_FILE_EXTENT_INLINE);
3617 	ptr = btrfs_file_extent_inline_start(ei);
3618 	write_extent_buffer(leaf, symname, ptr, name_len);
3619 	btrfs_mark_buffer_dirty(leaf);
3620 	btrfs_free_path(path);
3621 
3622 	inode->i_op = &btrfs_symlink_inode_operations;
3623 	inode->i_mapping->a_ops = &btrfs_symlink_aops;
3624 	inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3625 	btrfs_i_size_write(inode, name_len - 1);
3626 	err = btrfs_update_inode(trans, root, inode);
3627 	if (err)
3628 		drop_inode = 1;
3629 
3630 out_unlock:
3631 	nr = trans->blocks_used;
3632 	btrfs_end_transaction_throttle(trans, root);
3633 out_fail:
3634 	if (drop_inode) {
3635 		inode_dec_link_count(inode);
3636 		iput(inode);
3637 	}
3638 	btrfs_btree_balance_dirty(root, nr);
3639 	return err;
3640 }
3641 
3642 static int btrfs_set_page_dirty(struct page *page)
3643 {
3644 	return __set_page_dirty_nobuffers(page);
3645 }
3646 
3647 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
3648 static int btrfs_permission(struct inode *inode, int mask)
3649 #else
3650 static int btrfs_permission(struct inode *inode, int mask,
3651 			    struct nameidata *nd)
3652 #endif
3653 {
3654 	if (btrfs_test_flag(inode, READONLY) && (mask & MAY_WRITE))
3655 		return -EACCES;
3656 	return generic_permission(inode, mask, btrfs_check_acl);
3657 }
3658 
3659 static struct inode_operations btrfs_dir_inode_operations = {
3660 	.lookup		= btrfs_lookup,
3661 	.create		= btrfs_create,
3662 	.unlink		= btrfs_unlink,
3663 	.link		= btrfs_link,
3664 	.mkdir		= btrfs_mkdir,
3665 	.rmdir		= btrfs_rmdir,
3666 	.rename		= btrfs_rename,
3667 	.symlink	= btrfs_symlink,
3668 	.setattr	= btrfs_setattr,
3669 	.mknod		= btrfs_mknod,
3670 	.setxattr	= btrfs_setxattr,
3671 	.getxattr	= btrfs_getxattr,
3672 	.listxattr	= btrfs_listxattr,
3673 	.removexattr	= btrfs_removexattr,
3674 	.permission	= btrfs_permission,
3675 };
3676 static struct inode_operations btrfs_dir_ro_inode_operations = {
3677 	.lookup		= btrfs_lookup,
3678 	.permission	= btrfs_permission,
3679 };
3680 static struct file_operations btrfs_dir_file_operations = {
3681 	.llseek		= generic_file_llseek,
3682 	.read		= generic_read_dir,
3683 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
3684 	.readdir	= btrfs_nfshack_readdir,
3685 #else /* NFSd readdir/lookup deadlock is fixed */
3686 	.readdir	= btrfs_real_readdir,
3687 #endif
3688 	.unlocked_ioctl	= btrfs_ioctl,
3689 #ifdef CONFIG_COMPAT
3690 	.compat_ioctl	= btrfs_ioctl,
3691 #endif
3692 	.release        = btrfs_release_file,
3693 	.fsync		= btrfs_sync_file,
3694 };
3695 
3696 static struct extent_io_ops btrfs_extent_io_ops = {
3697 	.fill_delalloc = run_delalloc_range,
3698 	.submit_bio_hook = btrfs_submit_bio_hook,
3699 	.merge_bio_hook = btrfs_merge_bio_hook,
3700 	.readpage_end_io_hook = btrfs_readpage_end_io_hook,
3701 	.writepage_end_io_hook = btrfs_writepage_end_io_hook,
3702 	.writepage_start_hook = btrfs_writepage_start_hook,
3703 	.readpage_io_failed_hook = btrfs_io_failed_hook,
3704 	.set_bit_hook = btrfs_set_bit_hook,
3705 	.clear_bit_hook = btrfs_clear_bit_hook,
3706 };
3707 
3708 static struct address_space_operations btrfs_aops = {
3709 	.readpage	= btrfs_readpage,
3710 	.writepage	= btrfs_writepage,
3711 	.writepages	= btrfs_writepages,
3712 	.readpages	= btrfs_readpages,
3713 	.sync_page	= block_sync_page,
3714 	.bmap		= btrfs_bmap,
3715 	.direct_IO	= btrfs_direct_IO,
3716 	.invalidatepage = btrfs_invalidatepage,
3717 	.releasepage	= btrfs_releasepage,
3718 	.set_page_dirty	= btrfs_set_page_dirty,
3719 };
3720 
3721 static struct address_space_operations btrfs_symlink_aops = {
3722 	.readpage	= btrfs_readpage,
3723 	.writepage	= btrfs_writepage,
3724 	.invalidatepage = btrfs_invalidatepage,
3725 	.releasepage	= btrfs_releasepage,
3726 };
3727 
3728 static struct inode_operations btrfs_file_inode_operations = {
3729 	.truncate	= btrfs_truncate,
3730 	.getattr	= btrfs_getattr,
3731 	.setattr	= btrfs_setattr,
3732 	.setxattr	= btrfs_setxattr,
3733 	.getxattr	= btrfs_getxattr,
3734 	.listxattr      = btrfs_listxattr,
3735 	.removexattr	= btrfs_removexattr,
3736 	.permission	= btrfs_permission,
3737 };
3738 static struct inode_operations btrfs_special_inode_operations = {
3739 	.getattr	= btrfs_getattr,
3740 	.setattr	= btrfs_setattr,
3741 	.permission	= btrfs_permission,
3742 	.setxattr	= btrfs_setxattr,
3743 	.getxattr	= btrfs_getxattr,
3744 	.listxattr	= btrfs_listxattr,
3745 	.removexattr	= btrfs_removexattr,
3746 };
3747 static struct inode_operations btrfs_symlink_inode_operations = {
3748 	.readlink	= generic_readlink,
3749 	.follow_link	= page_follow_link_light,
3750 	.put_link	= page_put_link,
3751 	.permission	= btrfs_permission,
3752 };
3753