xref: /openbmc/linux/fs/btrfs/inode-item.c (revision d5e09e38)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #include "ctree.h"
7 #include "fs.h"
8 #include "messages.h"
9 #include "inode-item.h"
10 #include "disk-io.h"
11 #include "transaction.h"
12 #include "print-tree.h"
13 #include "space-info.h"
14 #include "accessors.h"
15 #include "extent-tree.h"
16 #include "file-item.h"
17 
btrfs_find_name_in_backref(struct extent_buffer * leaf,int slot,const struct fscrypt_str * name)18 struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
19 						   int slot,
20 						   const struct fscrypt_str *name)
21 {
22 	struct btrfs_inode_ref *ref;
23 	unsigned long ptr;
24 	unsigned long name_ptr;
25 	u32 item_size;
26 	u32 cur_offset = 0;
27 	int len;
28 
29 	item_size = btrfs_item_size(leaf, slot);
30 	ptr = btrfs_item_ptr_offset(leaf, slot);
31 	while (cur_offset < item_size) {
32 		ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
33 		len = btrfs_inode_ref_name_len(leaf, ref);
34 		name_ptr = (unsigned long)(ref + 1);
35 		cur_offset += len + sizeof(*ref);
36 		if (len != name->len)
37 			continue;
38 		if (memcmp_extent_buffer(leaf, name->name, name_ptr,
39 					 name->len) == 0)
40 			return ref;
41 	}
42 	return NULL;
43 }
44 
btrfs_find_name_in_ext_backref(struct extent_buffer * leaf,int slot,u64 ref_objectid,const struct fscrypt_str * name)45 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
46 		struct extent_buffer *leaf, int slot, u64 ref_objectid,
47 		const struct fscrypt_str *name)
48 {
49 	struct btrfs_inode_extref *extref;
50 	unsigned long ptr;
51 	unsigned long name_ptr;
52 	u32 item_size;
53 	u32 cur_offset = 0;
54 	int ref_name_len;
55 
56 	item_size = btrfs_item_size(leaf, slot);
57 	ptr = btrfs_item_ptr_offset(leaf, slot);
58 
59 	/*
60 	 * Search all extended backrefs in this item. We're only
61 	 * looking through any collisions so most of the time this is
62 	 * just going to compare against one buffer. If all is well,
63 	 * we'll return success and the inode ref object.
64 	 */
65 	while (cur_offset < item_size) {
66 		extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
67 		name_ptr = (unsigned long)(&extref->name);
68 		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
69 
70 		if (ref_name_len == name->len &&
71 		    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
72 		    (memcmp_extent_buffer(leaf, name->name, name_ptr,
73 					  name->len) == 0))
74 			return extref;
75 
76 		cur_offset += ref_name_len + sizeof(*extref);
77 	}
78 	return NULL;
79 }
80 
81 /* Returns NULL if no extref found */
82 struct btrfs_inode_extref *
btrfs_lookup_inode_extref(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,const struct fscrypt_str * name,u64 inode_objectid,u64 ref_objectid,int ins_len,int cow)83 btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
84 			  struct btrfs_root *root,
85 			  struct btrfs_path *path,
86 			  const struct fscrypt_str *name,
87 			  u64 inode_objectid, u64 ref_objectid, int ins_len,
88 			  int cow)
89 {
90 	int ret;
91 	struct btrfs_key key;
92 
93 	key.objectid = inode_objectid;
94 	key.type = BTRFS_INODE_EXTREF_KEY;
95 	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
96 
97 	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
98 	if (ret < 0)
99 		return ERR_PTR(ret);
100 	if (ret > 0)
101 		return NULL;
102 	return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
103 					      ref_objectid, name);
104 
105 }
106 
btrfs_del_inode_extref(struct btrfs_trans_handle * trans,struct btrfs_root * root,const struct fscrypt_str * name,u64 inode_objectid,u64 ref_objectid,u64 * index)107 static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
108 				  struct btrfs_root *root,
109 				  const struct fscrypt_str *name,
110 				  u64 inode_objectid, u64 ref_objectid,
111 				  u64 *index)
112 {
113 	struct btrfs_path *path;
114 	struct btrfs_key key;
115 	struct btrfs_inode_extref *extref;
116 	struct extent_buffer *leaf;
117 	int ret;
118 	int del_len = name->len + sizeof(*extref);
119 	unsigned long ptr;
120 	unsigned long item_start;
121 	u32 item_size;
122 
123 	key.objectid = inode_objectid;
124 	key.type = BTRFS_INODE_EXTREF_KEY;
125 	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
126 
127 	path = btrfs_alloc_path();
128 	if (!path)
129 		return -ENOMEM;
130 
131 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
132 	if (ret > 0)
133 		ret = -ENOENT;
134 	if (ret < 0)
135 		goto out;
136 
137 	/*
138 	 * Sanity check - did we find the right item for this name?
139 	 * This should always succeed so error here will make the FS
140 	 * readonly.
141 	 */
142 	extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
143 						ref_objectid, name);
144 	if (!extref) {
145 		btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
146 		ret = -EROFS;
147 		goto out;
148 	}
149 
150 	leaf = path->nodes[0];
151 	item_size = btrfs_item_size(leaf, path->slots[0]);
152 	if (index)
153 		*index = btrfs_inode_extref_index(leaf, extref);
154 
155 	if (del_len == item_size) {
156 		/*
157 		 * Common case only one ref in the item, remove the
158 		 * whole item.
159 		 */
160 		ret = btrfs_del_item(trans, root, path);
161 		goto out;
162 	}
163 
164 	ptr = (unsigned long)extref;
165 	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
166 
167 	memmove_extent_buffer(leaf, ptr, ptr + del_len,
168 			      item_size - (ptr + del_len - item_start));
169 
170 	btrfs_truncate_item(trans, path, item_size - del_len, 1);
171 
172 out:
173 	btrfs_free_path(path);
174 
175 	return ret;
176 }
177 
btrfs_del_inode_ref(struct btrfs_trans_handle * trans,struct btrfs_root * root,const struct fscrypt_str * name,u64 inode_objectid,u64 ref_objectid,u64 * index)178 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
179 			struct btrfs_root *root, const struct fscrypt_str *name,
180 			u64 inode_objectid, u64 ref_objectid, u64 *index)
181 {
182 	struct btrfs_path *path;
183 	struct btrfs_key key;
184 	struct btrfs_inode_ref *ref;
185 	struct extent_buffer *leaf;
186 	unsigned long ptr;
187 	unsigned long item_start;
188 	u32 item_size;
189 	u32 sub_item_len;
190 	int ret;
191 	int search_ext_refs = 0;
192 	int del_len = name->len + sizeof(*ref);
193 
194 	key.objectid = inode_objectid;
195 	key.offset = ref_objectid;
196 	key.type = BTRFS_INODE_REF_KEY;
197 
198 	path = btrfs_alloc_path();
199 	if (!path)
200 		return -ENOMEM;
201 
202 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
203 	if (ret > 0) {
204 		ret = -ENOENT;
205 		search_ext_refs = 1;
206 		goto out;
207 	} else if (ret < 0) {
208 		goto out;
209 	}
210 
211 	ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name);
212 	if (!ref) {
213 		ret = -ENOENT;
214 		search_ext_refs = 1;
215 		goto out;
216 	}
217 	leaf = path->nodes[0];
218 	item_size = btrfs_item_size(leaf, path->slots[0]);
219 
220 	if (index)
221 		*index = btrfs_inode_ref_index(leaf, ref);
222 
223 	if (del_len == item_size) {
224 		ret = btrfs_del_item(trans, root, path);
225 		goto out;
226 	}
227 	ptr = (unsigned long)ref;
228 	sub_item_len = name->len + sizeof(*ref);
229 	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
230 	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
231 			      item_size - (ptr + sub_item_len - item_start));
232 	btrfs_truncate_item(trans, path, item_size - sub_item_len, 1);
233 out:
234 	btrfs_free_path(path);
235 
236 	if (search_ext_refs) {
237 		/*
238 		 * No refs were found, or we could not find the
239 		 * name in our ref array. Find and remove the extended
240 		 * inode ref then.
241 		 */
242 		return btrfs_del_inode_extref(trans, root, name,
243 					      inode_objectid, ref_objectid, index);
244 	}
245 
246 	return ret;
247 }
248 
249 /*
250  * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
251  *
252  * The caller must have checked against BTRFS_LINK_MAX already.
253  */
btrfs_insert_inode_extref(struct btrfs_trans_handle * trans,struct btrfs_root * root,const struct fscrypt_str * name,u64 inode_objectid,u64 ref_objectid,u64 index)254 static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
255 				     struct btrfs_root *root,
256 				     const struct fscrypt_str *name,
257 				     u64 inode_objectid, u64 ref_objectid,
258 				     u64 index)
259 {
260 	struct btrfs_inode_extref *extref;
261 	int ret;
262 	int ins_len = name->len + sizeof(*extref);
263 	unsigned long ptr;
264 	struct btrfs_path *path;
265 	struct btrfs_key key;
266 	struct extent_buffer *leaf;
267 
268 	key.objectid = inode_objectid;
269 	key.type = BTRFS_INODE_EXTREF_KEY;
270 	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
271 
272 	path = btrfs_alloc_path();
273 	if (!path)
274 		return -ENOMEM;
275 
276 	ret = btrfs_insert_empty_item(trans, root, path, &key,
277 				      ins_len);
278 	if (ret == -EEXIST) {
279 		if (btrfs_find_name_in_ext_backref(path->nodes[0],
280 						   path->slots[0],
281 						   ref_objectid,
282 						   name))
283 			goto out;
284 
285 		btrfs_extend_item(trans, path, ins_len);
286 		ret = 0;
287 	}
288 	if (ret < 0)
289 		goto out;
290 
291 	leaf = path->nodes[0];
292 	ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
293 	ptr += btrfs_item_size(leaf, path->slots[0]) - ins_len;
294 	extref = (struct btrfs_inode_extref *)ptr;
295 
296 	btrfs_set_inode_extref_name_len(path->nodes[0], extref, name->len);
297 	btrfs_set_inode_extref_index(path->nodes[0], extref, index);
298 	btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
299 
300 	ptr = (unsigned long)&extref->name;
301 	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
302 	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
303 
304 out:
305 	btrfs_free_path(path);
306 	return ret;
307 }
308 
309 /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
btrfs_insert_inode_ref(struct btrfs_trans_handle * trans,struct btrfs_root * root,const struct fscrypt_str * name,u64 inode_objectid,u64 ref_objectid,u64 index)310 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
311 			   struct btrfs_root *root, const struct fscrypt_str *name,
312 			   u64 inode_objectid, u64 ref_objectid, u64 index)
313 {
314 	struct btrfs_fs_info *fs_info = root->fs_info;
315 	struct btrfs_path *path;
316 	struct btrfs_key key;
317 	struct btrfs_inode_ref *ref;
318 	unsigned long ptr;
319 	int ret;
320 	int ins_len = name->len + sizeof(*ref);
321 
322 	key.objectid = inode_objectid;
323 	key.offset = ref_objectid;
324 	key.type = BTRFS_INODE_REF_KEY;
325 
326 	path = btrfs_alloc_path();
327 	if (!path)
328 		return -ENOMEM;
329 
330 	path->skip_release_on_error = 1;
331 	ret = btrfs_insert_empty_item(trans, root, path, &key,
332 				      ins_len);
333 	if (ret == -EEXIST) {
334 		u32 old_size;
335 		ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
336 						 name);
337 		if (ref)
338 			goto out;
339 
340 		old_size = btrfs_item_size(path->nodes[0], path->slots[0]);
341 		btrfs_extend_item(trans, path, ins_len);
342 		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
343 				     struct btrfs_inode_ref);
344 		ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
345 		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
346 		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
347 		ptr = (unsigned long)(ref + 1);
348 		ret = 0;
349 	} else if (ret < 0) {
350 		if (ret == -EOVERFLOW) {
351 			if (btrfs_find_name_in_backref(path->nodes[0],
352 						       path->slots[0],
353 						       name))
354 				ret = -EEXIST;
355 			else
356 				ret = -EMLINK;
357 		}
358 		goto out;
359 	} else {
360 		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
361 				     struct btrfs_inode_ref);
362 		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
363 		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
364 		ptr = (unsigned long)(ref + 1);
365 	}
366 	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
367 	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
368 
369 out:
370 	btrfs_free_path(path);
371 
372 	if (ret == -EMLINK) {
373 		struct btrfs_super_block *disk_super = fs_info->super_copy;
374 		/* We ran out of space in the ref array. Need to
375 		 * add an extended ref. */
376 		if (btrfs_super_incompat_flags(disk_super)
377 		    & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
378 			ret = btrfs_insert_inode_extref(trans, root, name,
379 							inode_objectid,
380 							ref_objectid, index);
381 	}
382 
383 	return ret;
384 }
385 
btrfs_insert_empty_inode(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 objectid)386 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
387 			     struct btrfs_root *root,
388 			     struct btrfs_path *path, u64 objectid)
389 {
390 	struct btrfs_key key;
391 	int ret;
392 	key.objectid = objectid;
393 	key.type = BTRFS_INODE_ITEM_KEY;
394 	key.offset = 0;
395 
396 	ret = btrfs_insert_empty_item(trans, root, path, &key,
397 				      sizeof(struct btrfs_inode_item));
398 	return ret;
399 }
400 
btrfs_lookup_inode(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,struct btrfs_key * location,int mod)401 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
402 		       *root, struct btrfs_path *path,
403 		       struct btrfs_key *location, int mod)
404 {
405 	int ins_len = mod < 0 ? -1 : 0;
406 	int cow = mod != 0;
407 	int ret;
408 	int slot;
409 	struct extent_buffer *leaf;
410 	struct btrfs_key found_key;
411 
412 	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
413 	if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
414 	    location->offset == (u64)-1 && path->slots[0] != 0) {
415 		slot = path->slots[0] - 1;
416 		leaf = path->nodes[0];
417 		btrfs_item_key_to_cpu(leaf, &found_key, slot);
418 		if (found_key.objectid == location->objectid &&
419 		    found_key.type == location->type) {
420 			path->slots[0]--;
421 			return 0;
422 		}
423 	}
424 	return ret;
425 }
426 
btrfs_trace_truncate(struct btrfs_inode * inode,struct extent_buffer * leaf,struct btrfs_file_extent_item * fi,u64 offset,int extent_type,int slot)427 static inline void btrfs_trace_truncate(struct btrfs_inode *inode,
428 					struct extent_buffer *leaf,
429 					struct btrfs_file_extent_item *fi,
430 					u64 offset, int extent_type, int slot)
431 {
432 	if (!inode)
433 		return;
434 	if (extent_type == BTRFS_FILE_EXTENT_INLINE)
435 		trace_btrfs_truncate_show_fi_inline(inode, leaf, fi, slot,
436 						    offset);
437 	else
438 		trace_btrfs_truncate_show_fi_regular(inode, leaf, fi, offset);
439 }
440 
441 /*
442  * Remove inode items from a given root.
443  *
444  * @trans:		A transaction handle.
445  * @root:		The root from which to remove items.
446  * @inode:		The inode whose items we want to remove.
447  * @control:		The btrfs_truncate_control to control how and what we
448  *			are truncating.
449  *
450  * Remove all keys associated with the inode from the given root that have a key
451  * with a type greater than or equals to @min_type. When @min_type has a value of
452  * BTRFS_EXTENT_DATA_KEY, only remove file extent items that have an offset value
453  * greater than or equals to @new_size. If a file extent item that starts before
454  * @new_size and ends after it is found, its length is adjusted.
455  *
456  * Returns: 0 on success, < 0 on error and NEED_TRUNCATE_BLOCK when @min_type is
457  * BTRFS_EXTENT_DATA_KEY and the caller must truncate the last block.
458  */
btrfs_truncate_inode_items(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_truncate_control * control)459 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
460 			       struct btrfs_root *root,
461 			       struct btrfs_truncate_control *control)
462 {
463 	struct btrfs_fs_info *fs_info = root->fs_info;
464 	struct btrfs_path *path;
465 	struct extent_buffer *leaf;
466 	struct btrfs_file_extent_item *fi;
467 	struct btrfs_key key;
468 	struct btrfs_key found_key;
469 	u64 new_size = control->new_size;
470 	u64 extent_num_bytes = 0;
471 	u64 extent_offset = 0;
472 	u64 item_end = 0;
473 	u32 found_type = (u8)-1;
474 	int del_item;
475 	int pending_del_nr = 0;
476 	int pending_del_slot = 0;
477 	int extent_type = -1;
478 	int ret;
479 	u64 bytes_deleted = 0;
480 	bool be_nice = false;
481 
482 	ASSERT(control->inode || !control->clear_extent_range);
483 	ASSERT(new_size == 0 || control->min_type == BTRFS_EXTENT_DATA_KEY);
484 
485 	control->last_size = new_size;
486 	control->sub_bytes = 0;
487 
488 	/*
489 	 * For shareable roots we want to back off from time to time, this turns
490 	 * out to be subvolume roots, reloc roots, and data reloc roots.
491 	 */
492 	if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
493 		be_nice = true;
494 
495 	path = btrfs_alloc_path();
496 	if (!path)
497 		return -ENOMEM;
498 	path->reada = READA_BACK;
499 
500 	key.objectid = control->ino;
501 	key.offset = (u64)-1;
502 	key.type = (u8)-1;
503 
504 search_again:
505 	/*
506 	 * With a 16K leaf size and 128MiB extents, you can actually queue up a
507 	 * huge file in a single leaf.  Most of the time that bytes_deleted is
508 	 * > 0, it will be huge by the time we get here
509 	 */
510 	if (be_nice && bytes_deleted > SZ_32M &&
511 	    btrfs_should_end_transaction(trans)) {
512 		ret = -EAGAIN;
513 		goto out;
514 	}
515 
516 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
517 	if (ret < 0)
518 		goto out;
519 
520 	if (ret > 0) {
521 		ret = 0;
522 		/* There are no items in the tree for us to truncate, we're done */
523 		if (path->slots[0] == 0)
524 			goto out;
525 		path->slots[0]--;
526 	}
527 
528 	while (1) {
529 		u64 clear_start = 0, clear_len = 0, extent_start = 0;
530 		bool refill_delayed_refs_rsv = false;
531 
532 		fi = NULL;
533 		leaf = path->nodes[0];
534 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
535 		found_type = found_key.type;
536 
537 		if (found_key.objectid != control->ino)
538 			break;
539 
540 		if (found_type < control->min_type)
541 			break;
542 
543 		item_end = found_key.offset;
544 		if (found_type == BTRFS_EXTENT_DATA_KEY) {
545 			fi = btrfs_item_ptr(leaf, path->slots[0],
546 					    struct btrfs_file_extent_item);
547 			extent_type = btrfs_file_extent_type(leaf, fi);
548 			if (extent_type != BTRFS_FILE_EXTENT_INLINE)
549 				item_end +=
550 				    btrfs_file_extent_num_bytes(leaf, fi);
551 			else if (extent_type == BTRFS_FILE_EXTENT_INLINE)
552 				item_end += btrfs_file_extent_ram_bytes(leaf, fi);
553 
554 			btrfs_trace_truncate(control->inode, leaf, fi,
555 					     found_key.offset, extent_type,
556 					     path->slots[0]);
557 			item_end--;
558 		}
559 		if (found_type > control->min_type) {
560 			del_item = 1;
561 		} else {
562 			if (item_end < new_size)
563 				break;
564 			if (found_key.offset >= new_size)
565 				del_item = 1;
566 			else
567 				del_item = 0;
568 		}
569 
570 		/* FIXME, shrink the extent if the ref count is only 1 */
571 		if (found_type != BTRFS_EXTENT_DATA_KEY)
572 			goto delete;
573 
574 		control->extents_found++;
575 
576 		if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
577 			u64 num_dec;
578 
579 			clear_start = found_key.offset;
580 			extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
581 			if (!del_item) {
582 				u64 orig_num_bytes =
583 					btrfs_file_extent_num_bytes(leaf, fi);
584 				extent_num_bytes = ALIGN(new_size -
585 						found_key.offset,
586 						fs_info->sectorsize);
587 				clear_start = ALIGN(new_size, fs_info->sectorsize);
588 
589 				btrfs_set_file_extent_num_bytes(leaf, fi,
590 							 extent_num_bytes);
591 				num_dec = (orig_num_bytes - extent_num_bytes);
592 				if (extent_start != 0)
593 					control->sub_bytes += num_dec;
594 				btrfs_mark_buffer_dirty(trans, leaf);
595 			} else {
596 				extent_num_bytes =
597 					btrfs_file_extent_disk_num_bytes(leaf, fi);
598 				extent_offset = found_key.offset -
599 					btrfs_file_extent_offset(leaf, fi);
600 
601 				/* FIXME blocksize != 4096 */
602 				num_dec = btrfs_file_extent_num_bytes(leaf, fi);
603 				if (extent_start != 0)
604 					control->sub_bytes += num_dec;
605 			}
606 			clear_len = num_dec;
607 		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
608 			/*
609 			 * We can't truncate inline items that have had
610 			 * special encodings
611 			 */
612 			if (!del_item &&
613 			    btrfs_file_extent_encryption(leaf, fi) == 0 &&
614 			    btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
615 			    btrfs_file_extent_compression(leaf, fi) == 0) {
616 				u32 size = (u32)(new_size - found_key.offset);
617 
618 				btrfs_set_file_extent_ram_bytes(leaf, fi, size);
619 				size = btrfs_file_extent_calc_inline_size(size);
620 				btrfs_truncate_item(trans, path, size, 1);
621 			} else if (!del_item) {
622 				/*
623 				 * We have to bail so the last_size is set to
624 				 * just before this extent.
625 				 */
626 				ret = BTRFS_NEED_TRUNCATE_BLOCK;
627 				break;
628 			} else {
629 				/*
630 				 * Inline extents are special, we just treat
631 				 * them as a full sector worth in the file
632 				 * extent tree just for simplicity sake.
633 				 */
634 				clear_len = fs_info->sectorsize;
635 			}
636 
637 			control->sub_bytes += item_end + 1 - new_size;
638 		}
639 delete:
640 		/*
641 		 * We only want to clear the file extent range if we're
642 		 * modifying the actual inode's mapping, which is just the
643 		 * normal truncate path.
644 		 */
645 		if (control->clear_extent_range) {
646 			ret = btrfs_inode_clear_file_extent_range(control->inode,
647 						  clear_start, clear_len);
648 			if (ret) {
649 				btrfs_abort_transaction(trans, ret);
650 				break;
651 			}
652 		}
653 
654 		if (del_item) {
655 			ASSERT(!pending_del_nr ||
656 			       ((path->slots[0] + 1) == pending_del_slot));
657 
658 			control->last_size = found_key.offset;
659 			if (!pending_del_nr) {
660 				/* No pending yet, add ourselves */
661 				pending_del_slot = path->slots[0];
662 				pending_del_nr = 1;
663 			} else if (path->slots[0] + 1 == pending_del_slot) {
664 				/* Hop on the pending chunk */
665 				pending_del_nr++;
666 				pending_del_slot = path->slots[0];
667 			}
668 		} else {
669 			control->last_size = new_size;
670 			break;
671 		}
672 
673 		if (del_item && extent_start != 0 && !control->skip_ref_updates) {
674 			struct btrfs_ref ref = { 0 };
675 
676 			bytes_deleted += extent_num_bytes;
677 
678 			btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF,
679 					extent_start, extent_num_bytes, 0);
680 			btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
681 					control->ino, extent_offset,
682 					root->root_key.objectid, false);
683 			ret = btrfs_free_extent(trans, &ref);
684 			if (ret) {
685 				btrfs_abort_transaction(trans, ret);
686 				break;
687 			}
688 			if (be_nice && btrfs_check_space_for_delayed_refs(fs_info))
689 				refill_delayed_refs_rsv = true;
690 		}
691 
692 		if (found_type == BTRFS_INODE_ITEM_KEY)
693 			break;
694 
695 		if (path->slots[0] == 0 ||
696 		    path->slots[0] != pending_del_slot ||
697 		    refill_delayed_refs_rsv) {
698 			if (pending_del_nr) {
699 				ret = btrfs_del_items(trans, root, path,
700 						pending_del_slot,
701 						pending_del_nr);
702 				if (ret) {
703 					btrfs_abort_transaction(trans, ret);
704 					break;
705 				}
706 				pending_del_nr = 0;
707 			}
708 			btrfs_release_path(path);
709 
710 			/*
711 			 * We can generate a lot of delayed refs, so we need to
712 			 * throttle every once and a while and make sure we're
713 			 * adding enough space to keep up with the work we are
714 			 * generating.  Since we hold a transaction here we
715 			 * can't flush, and we don't want to FLUSH_LIMIT because
716 			 * we could have generated too many delayed refs to
717 			 * actually allocate, so just bail if we're short and
718 			 * let the normal reservation dance happen higher up.
719 			 */
720 			if (refill_delayed_refs_rsv) {
721 				ret = btrfs_delayed_refs_rsv_refill(fs_info,
722 							BTRFS_RESERVE_NO_FLUSH);
723 				if (ret) {
724 					ret = -EAGAIN;
725 					break;
726 				}
727 			}
728 			goto search_again;
729 		} else {
730 			path->slots[0]--;
731 		}
732 	}
733 out:
734 	if (ret >= 0 && pending_del_nr) {
735 		int err;
736 
737 		err = btrfs_del_items(trans, root, path, pending_del_slot,
738 				      pending_del_nr);
739 		if (err) {
740 			btrfs_abort_transaction(trans, err);
741 			ret = err;
742 		}
743 	}
744 
745 	ASSERT(control->last_size >= new_size);
746 	if (!ret && control->last_size > new_size)
747 		control->last_size = new_size;
748 
749 	btrfs_free_path(path);
750 	return ret;
751 }
752