1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* Copyright (C) 2007 Oracle. All rights reserved.
4	*/
5
6	#include <linux/sched.h>
7	#include <linux/sched/signal.h>
8	#include <linux/pagemap.h>
9	#include <linux/writeback.h>
10	#include <linux/blkdev.h>
11	#include <linux/sort.h>
12	#include <linux/rcupdate.h>
13	#include <linux/kthread.h>
14	#include <linux/slab.h>
15	#include <linux/ratelimit.h>
16	#include <linux/percpu_counter.h>
17	#include <linux/lockdep.h>
18	#include <linux/crc32c.h>
19	#include "ctree.h"
20	#include "extent-tree.h"
21	#include "tree-log.h"
22	#include "disk-io.h"
23	#include "print-tree.h"
24	#include "volumes.h"
25	#include "raid56.h"
26	#include "locking.h"
27	#include "free-space-cache.h"
28	#include "free-space-tree.h"
29	#include "sysfs.h"
30	#include "qgroup.h"
31	#include "ref-verify.h"
32	#include "space-info.h"
33	#include "block-rsv.h"
34	#include "delalloc-space.h"
35	#include "discard.h"
36	#include "rcu-string.h"
37	#include "zoned.h"
38	#include "dev-replace.h"
39	#include "fs.h"
40	#include "accessors.h"
41	#include "root-tree.h"
42	#include "file-item.h"
43	#include "orphan.h"
44	#include "tree-checker.h"
45	#include "raid-stripe-tree.h"
46
47	#undef SCRAMBLE_DELAYED_REFS
48
49
50	static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
51	struct btrfs_delayed_ref_head *href,
52	struct btrfs_delayed_ref_node *node, u64 parent,
53	u64 root_objectid, u64 owner_objectid,
54	u64 owner_offset,
55	struct btrfs_delayed_extent_op *extra_op);
56	static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
57	struct extent_buffer *leaf,
58	struct btrfs_extent_item *ei);
59	static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
60	u64 parent, u64 root_objectid,
61	u64 flags, u64 owner, u64 offset,
62	struct btrfs_key *ins, int ref_mod, u64 oref_root);
63	static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
64	struct btrfs_delayed_ref_node *node,
65	struct btrfs_delayed_extent_op *extent_op);
66	static int find_next_key(struct btrfs_path *path, int level,
67	struct btrfs_key *key);
68
69	static int block_group_bits(struct btrfs_block_group *cache, u64 bits)
70	{
71	return (cache->flags & bits) == bits;
72	}
73
74	/* simple helper to search for an existing data extent at a given offset */
75	int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
76	{
77	struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr: start);
78	int ret;
79	struct btrfs_key key;
80	struct btrfs_path *path;
81
82	path = btrfs_alloc_path();
83	if (!path)
84	return -ENOMEM;
85
86	key.objectid = start;
87	key.offset = len;
88	key.type = BTRFS_EXTENT_ITEM_KEY;
89	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
90	btrfs_free_path(p: path);
91	return ret;
92	}
93
94	/*
95	* helper function to lookup reference count and flags of a tree block.
96	*
97	* the head node for delayed ref is used to store the sum of all the
98	* reference count modifications queued up in the rbtree. the head
99	* node may also store the extent flags to set. This way you can check
100	* to see what the reference count and extent flags would be if all of
101	* the delayed refs are not processed.
102	*/
103	int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
104	struct btrfs_fs_info *fs_info, u64 bytenr,
105	u64 offset, int metadata, u64 *refs, u64 *flags)
106	{
107	struct btrfs_root *extent_root;
108	struct btrfs_delayed_ref_head *head;
109	struct btrfs_delayed_ref_root *delayed_refs;
110	struct btrfs_path *path;
111	struct btrfs_extent_item *ei;
112	struct extent_buffer *leaf;
113	struct btrfs_key key;
114	u32 item_size;
115	u64 num_refs;
116	u64 extent_flags;
117	int ret;
118
119	/*
120	* If we don't have skinny metadata, don't bother doing anything
121	* different
122	*/
123	if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
124	offset = fs_info->nodesize;
125	metadata = 0;
126	}
127
128	path = btrfs_alloc_path();
129	if (!path)
130	return -ENOMEM;
131
132	if (!trans) {
133	path->skip_locking = 1;
134	path->search_commit_root = 1;
135	}
136
137	search_again:
138	key.objectid = bytenr;
139	key.offset = offset;
140	if (metadata)
141	key.type = BTRFS_METADATA_ITEM_KEY;
142	else
143	key.type = BTRFS_EXTENT_ITEM_KEY;
144
145	extent_root = btrfs_extent_root(fs_info, bytenr);
146	ret = btrfs_search_slot(NULL, root: extent_root, key: &key, p: path, ins_len: 0, cow: 0);
147	if (ret < 0)
148	goto out_free;
149
150	if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
151	if (path->slots[0]) {
152	path->slots[0]--;
153	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key,
154	nr: path->slots[0]);
155	if (key.objectid == bytenr &&
156	key.type == BTRFS_EXTENT_ITEM_KEY &&
157	key.offset == fs_info->nodesize)
158	ret = 0;
159	}
160	}
161
162	if (ret == 0) {
163	leaf = path->nodes[0];
164	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
165	if (item_size >= sizeof(*ei)) {
166	ei = btrfs_item_ptr(leaf, path->slots[0],
167	struct btrfs_extent_item);
168	num_refs = btrfs_extent_refs(eb: leaf, s: ei);
169	extent_flags = btrfs_extent_flags(eb: leaf, s: ei);
170	} else {
171	ret = -EUCLEAN;
172	btrfs_err(fs_info,
173	"unexpected extent item size, has %u expect >= %zu",
174	item_size, sizeof(*ei));
175	if (trans)
176	btrfs_abort_transaction(trans, ret);
177	else
178	btrfs_handle_fs_error(fs_info, ret, NULL);
179
180	goto out_free;
181	}
182
183	BUG_ON(num_refs == 0);
184	} else {
185	num_refs = 0;
186	extent_flags = 0;
187	ret = 0;
188	}
189
190	if (!trans)
191	goto out;
192
193	delayed_refs = &trans->transaction->delayed_refs;
194	spin_lock(lock: &delayed_refs->lock);
195	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
196	if (head) {
197	if (!mutex_trylock(lock: &head->mutex)) {
198	refcount_inc(r: &head->refs);
199	spin_unlock(lock: &delayed_refs->lock);
200
201	btrfs_release_path(p: path);
202
203	/*
204	* Mutex was contended, block until it's released and try
205	* again
206	*/
207	mutex_lock(&head->mutex);
208	mutex_unlock(lock: &head->mutex);
209	btrfs_put_delayed_ref_head(head);
210	goto search_again;
211	}
212	spin_lock(lock: &head->lock);
213	if (head->extent_op && head->extent_op->update_flags)
214	extent_flags |= head->extent_op->flags_to_set;
215	else
216	BUG_ON(num_refs == 0);
217
218	num_refs += head->ref_mod;
219	spin_unlock(lock: &head->lock);
220	mutex_unlock(lock: &head->mutex);
221	}
222	spin_unlock(lock: &delayed_refs->lock);
223	out:
224	WARN_ON(num_refs == 0);
225	if (refs)
226	*refs = num_refs;
227	if (flags)
228	*flags = extent_flags;
229	out_free:
230	btrfs_free_path(p: path);
231	return ret;
232	}
233
234	/*
235	* Back reference rules. Back refs have three main goals:
236	*
237	* 1) differentiate between all holders of references to an extent so that
238	* when a reference is dropped we can make sure it was a valid reference
239	* before freeing the extent.
240	*
241	* 2) Provide enough information to quickly find the holders of an extent
242	* if we notice a given block is corrupted or bad.
243	*
244	* 3) Make it easy to migrate blocks for FS shrinking or storage pool
245	* maintenance. This is actually the same as #2, but with a slightly
246	* different use case.
247	*
248	* There are two kinds of back refs. The implicit back refs is optimized
249	* for pointers in non-shared tree blocks. For a given pointer in a block,
250	* back refs of this kind provide information about the block's owner tree
251	* and the pointer's key. These information allow us to find the block by
252	* b-tree searching. The full back refs is for pointers in tree blocks not
253	* referenced by their owner trees. The location of tree block is recorded
254	* in the back refs. Actually the full back refs is generic, and can be
255	* used in all cases the implicit back refs is used. The major shortcoming
256	* of the full back refs is its overhead. Every time a tree block gets
257	* COWed, we have to update back refs entry for all pointers in it.
258	*
259	* For a newly allocated tree block, we use implicit back refs for
260	* pointers in it. This means most tree related operations only involve
261	* implicit back refs. For a tree block created in old transaction, the
262	* only way to drop a reference to it is COW it. So we can detect the
263	* event that tree block loses its owner tree's reference and do the
264	* back refs conversion.
265	*
266	* When a tree block is COWed through a tree, there are four cases:
267	*
268	* The reference count of the block is one and the tree is the block's
269	* owner tree. Nothing to do in this case.
270	*
271	* The reference count of the block is one and the tree is not the
272	* block's owner tree. In this case, full back refs is used for pointers
273	* in the block. Remove these full back refs, add implicit back refs for
274	* every pointers in the new block.
275	*
276	* The reference count of the block is greater than one and the tree is
277	* the block's owner tree. In this case, implicit back refs is used for
278	* pointers in the block. Add full back refs for every pointers in the
279	* block, increase lower level extents' reference counts. The original
280	* implicit back refs are entailed to the new block.
281	*
282	* The reference count of the block is greater than one and the tree is
283	* not the block's owner tree. Add implicit back refs for every pointer in
284	* the new block, increase lower level extents' reference count.
285	*
286	* Back Reference Key composing:
287	*
288	* The key objectid corresponds to the first byte in the extent,
289	* The key type is used to differentiate between types of back refs.
290	* There are different meanings of the key offset for different types
291	* of back refs.
292	*
293	* File extents can be referenced by:
294	*
295	* - multiple snapshots, subvolumes, or different generations in one subvol
296	* - different files inside a single subvolume
297	* - different offsets inside a file (bookend extents in file.c)
298	*
299	* The extent ref structure for the implicit back refs has fields for:
300	*
301	* - Objectid of the subvolume root
302	* - objectid of the file holding the reference
303	* - original offset in the file
304	* - how many bookend extents
305	*
306	* The key offset for the implicit back refs is hash of the first
307	* three fields.
308	*
309	* The extent ref structure for the full back refs has field for:
310	*
311	* - number of pointers in the tree leaf
312	*
313	* The key offset for the implicit back refs is the first byte of
314	* the tree leaf
315	*
316	* When a file extent is allocated, The implicit back refs is used.
317	* the fields are filled in:
318	*
319	* (root_key.objectid, inode objectid, offset in file, 1)
320	*
321	* When a file extent is removed file truncation, we find the
322	* corresponding implicit back refs and check the following fields:
323	*
324	* (btrfs_header_owner(leaf), inode objectid, offset in file)
325	*
326	* Btree extents can be referenced by:
327	*
328	* - Different subvolumes
329	*
330	* Both the implicit back refs and the full back refs for tree blocks
331	* only consist of key. The key offset for the implicit back refs is
332	* objectid of block's owner tree. The key offset for the full back refs
333	* is the first byte of parent block.
334	*
335	* When implicit back refs is used, information about the lowest key and
336	* level of the tree block are required. These information are stored in
337	* tree block info structure.
338	*/
339
340	/*
341	* is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
342	* is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
343	* is_data == BTRFS_REF_TYPE_ANY, either type is OK.
344	*/
345	int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
346	struct btrfs_extent_inline_ref *iref,
347	enum btrfs_inline_ref_type is_data)
348	{
349	struct btrfs_fs_info *fs_info = eb->fs_info;
350	int type = btrfs_extent_inline_ref_type(eb, s: iref);
351	u64 offset = btrfs_extent_inline_ref_offset(eb, s: iref);
352
353	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
354	ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
355	return type;
356	}
357
358	if (type == BTRFS_TREE_BLOCK_REF_KEY ||
359	type == BTRFS_SHARED_BLOCK_REF_KEY ||
360	type == BTRFS_SHARED_DATA_REF_KEY ||
361	type == BTRFS_EXTENT_DATA_REF_KEY) {
362	if (is_data == BTRFS_REF_TYPE_BLOCK) {
363	if (type == BTRFS_TREE_BLOCK_REF_KEY)
364	return type;
365	if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
366	ASSERT(fs_info);
367	/*
368	* Every shared one has parent tree block,
369	* which must be aligned to sector size.
370	*/
371	if (offset && IS_ALIGNED(offset, fs_info->sectorsize))
372	return type;
373	}
374	} else if (is_data == BTRFS_REF_TYPE_DATA) {
375	if (type == BTRFS_EXTENT_DATA_REF_KEY)
376	return type;
377	if (type == BTRFS_SHARED_DATA_REF_KEY) {
378	ASSERT(fs_info);
379	/*
380	* Every shared one has parent tree block,
381	* which must be aligned to sector size.
382	*/
383	if (offset &&
384	IS_ALIGNED(offset, fs_info->sectorsize))
385	return type;
386	}
387	} else {
388	ASSERT(is_data == BTRFS_REF_TYPE_ANY);
389	return type;
390	}
391	}
392
393	WARN_ON(1);
394	btrfs_print_leaf(l: eb);
395	btrfs_err(fs_info,
396	"eb %llu iref 0x%lx invalid extent inline ref type %d",
397	eb->start, (unsigned long)iref, type);
398
399	return BTRFS_REF_TYPE_INVALID;
400	}
401
402	u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
403	{
404	u32 high_crc = ~(u32)0;
405	u32 low_crc = ~(u32)0;
406	__le64 lenum;
407
408	lenum = cpu_to_le64(root_objectid);
409	high_crc = crc32c(crc: high_crc, address: &lenum, length: sizeof(lenum));
410	lenum = cpu_to_le64(owner);
411	low_crc = crc32c(crc: low_crc, address: &lenum, length: sizeof(lenum));
412	lenum = cpu_to_le64(offset);
413	low_crc = crc32c(crc: low_crc, address: &lenum, length: sizeof(lenum));
414
415	return ((u64)high_crc << 31) ^ (u64)low_crc;
416	}
417
418	static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
419	struct btrfs_extent_data_ref *ref)
420	{
421	return hash_extent_data_ref(root_objectid: btrfs_extent_data_ref_root(eb: leaf, s: ref),
422	owner: btrfs_extent_data_ref_objectid(eb: leaf, s: ref),
423	offset: btrfs_extent_data_ref_offset(eb: leaf, s: ref));
424	}
425
426	static int match_extent_data_ref(struct extent_buffer *leaf,
427	struct btrfs_extent_data_ref *ref,
428	u64 root_objectid, u64 owner, u64 offset)
429	{
430	if (btrfs_extent_data_ref_root(eb: leaf, s: ref) != root_objectid ||
431	btrfs_extent_data_ref_objectid(eb: leaf, s: ref) != owner ||
432	btrfs_extent_data_ref_offset(eb: leaf, s: ref) != offset)
433	return 0;
434	return 1;
435	}
436
437	static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
438	struct btrfs_path *path,
439	u64 bytenr, u64 parent,
440	u64 root_objectid,
441	u64 owner, u64 offset)
442	{
443	struct btrfs_root *root = btrfs_extent_root(fs_info: trans->fs_info, bytenr);
444	struct btrfs_key key;
445	struct btrfs_extent_data_ref *ref;
446	struct extent_buffer *leaf;
447	u32 nritems;
448	int ret;
449	int recow;
450	int err = -ENOENT;
451
452	key.objectid = bytenr;
453	if (parent) {
454	key.type = BTRFS_SHARED_DATA_REF_KEY;
455	key.offset = parent;
456	} else {
457	key.type = BTRFS_EXTENT_DATA_REF_KEY;
458	key.offset = hash_extent_data_ref(root_objectid,
459	owner, offset);
460	}
461	again:
462	recow = 0;
463	ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1);
464	if (ret < 0) {
465	err = ret;
466	goto fail;
467	}
468
469	if (parent) {
470	if (!ret)
471	return 0;
472	goto fail;
473	}
474
475	leaf = path->nodes[0];
476	nritems = btrfs_header_nritems(eb: leaf);
477	while (1) {
478	if (path->slots[0] >= nritems) {
479	ret = btrfs_next_leaf(root, path);
480	if (ret < 0)
481	err = ret;
482	if (ret)
483	goto fail;
484
485	leaf = path->nodes[0];
486	nritems = btrfs_header_nritems(eb: leaf);
487	recow = 1;
488	}
489
490	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
491	if (key.objectid != bytenr ||
492	key.type != BTRFS_EXTENT_DATA_REF_KEY)
493	goto fail;
494
495	ref = btrfs_item_ptr(leaf, path->slots[0],
496	struct btrfs_extent_data_ref);
497
498	if (match_extent_data_ref(leaf, ref, root_objectid,
499	owner, offset)) {
500	if (recow) {
501	btrfs_release_path(p: path);
502	goto again;
503	}
504	err = 0;
505	break;
506	}
507	path->slots[0]++;
508	}
509	fail:
510	return err;
511	}
512
513	static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
514	struct btrfs_path *path,
515	u64 bytenr, u64 parent,
516	u64 root_objectid, u64 owner,
517	u64 offset, int refs_to_add)
518	{
519	struct btrfs_root *root = btrfs_extent_root(fs_info: trans->fs_info, bytenr);
520	struct btrfs_key key;
521	struct extent_buffer *leaf;
522	u32 size;
523	u32 num_refs;
524	int ret;
525
526	key.objectid = bytenr;
527	if (parent) {
528	key.type = BTRFS_SHARED_DATA_REF_KEY;
529	key.offset = parent;
530	size = sizeof(struct btrfs_shared_data_ref);
531	} else {
532	key.type = BTRFS_EXTENT_DATA_REF_KEY;
533	key.offset = hash_extent_data_ref(root_objectid,
534	owner, offset);
535	size = sizeof(struct btrfs_extent_data_ref);
536	}
537
538	ret = btrfs_insert_empty_item(trans, root, path, key: &key, data_size: size);
539	if (ret && ret != -EEXIST)
540	goto fail;
541
542	leaf = path->nodes[0];
543	if (parent) {
544	struct btrfs_shared_data_ref *ref;
545	ref = btrfs_item_ptr(leaf, path->slots[0],
546	struct btrfs_shared_data_ref);
547	if (ret == 0) {
548	btrfs_set_shared_data_ref_count(eb: leaf, s: ref, val: refs_to_add);
549	} else {
550	num_refs = btrfs_shared_data_ref_count(eb: leaf, s: ref);
551	num_refs += refs_to_add;
552	btrfs_set_shared_data_ref_count(eb: leaf, s: ref, val: num_refs);
553	}
554	} else {
555	struct btrfs_extent_data_ref *ref;
556	while (ret == -EEXIST) {
557	ref = btrfs_item_ptr(leaf, path->slots[0],
558	struct btrfs_extent_data_ref);
559	if (match_extent_data_ref(leaf, ref, root_objectid,
560	owner, offset))
561	break;
562	btrfs_release_path(p: path);
563	key.offset++;
564	ret = btrfs_insert_empty_item(trans, root, path, key: &key,
565	data_size: size);
566	if (ret && ret != -EEXIST)
567	goto fail;
568
569	leaf = path->nodes[0];
570	}
571	ref = btrfs_item_ptr(leaf, path->slots[0],
572	struct btrfs_extent_data_ref);
573	if (ret == 0) {
574	btrfs_set_extent_data_ref_root(eb: leaf, s: ref,
575	val: root_objectid);
576	btrfs_set_extent_data_ref_objectid(eb: leaf, s: ref, val: owner);
577	btrfs_set_extent_data_ref_offset(eb: leaf, s: ref, val: offset);
578	btrfs_set_extent_data_ref_count(eb: leaf, s: ref, val: refs_to_add);
579	} else {
580	num_refs = btrfs_extent_data_ref_count(eb: leaf, s: ref);
581	num_refs += refs_to_add;
582	btrfs_set_extent_data_ref_count(eb: leaf, s: ref, val: num_refs);
583	}
584	}
585	btrfs_mark_buffer_dirty(trans, buf: leaf);
586	ret = 0;
587	fail:
588	btrfs_release_path(p: path);
589	return ret;
590	}
591
592	static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
593	struct btrfs_root *root,
594	struct btrfs_path *path,
595	int refs_to_drop)
596	{
597	struct btrfs_key key;
598	struct btrfs_extent_data_ref *ref1 = NULL;
599	struct btrfs_shared_data_ref *ref2 = NULL;
600	struct extent_buffer *leaf;
601	u32 num_refs = 0;
602	int ret = 0;
603
604	leaf = path->nodes[0];
605	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
606
607	if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
608	ref1 = btrfs_item_ptr(leaf, path->slots[0],
609	struct btrfs_extent_data_ref);
610	num_refs = btrfs_extent_data_ref_count(eb: leaf, s: ref1);
611	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
612	ref2 = btrfs_item_ptr(leaf, path->slots[0],
613	struct btrfs_shared_data_ref);
614	num_refs = btrfs_shared_data_ref_count(eb: leaf, s: ref2);
615	} else {
616	btrfs_err(trans->fs_info,
617	"unrecognized backref key (%llu %u %llu)",
618	key.objectid, key.type, key.offset);
619	btrfs_abort_transaction(trans, -EUCLEAN);
620	return -EUCLEAN;
621	}
622
623	BUG_ON(num_refs < refs_to_drop);
624	num_refs -= refs_to_drop;
625
626	if (num_refs == 0) {
627	ret = btrfs_del_item(trans, root, path);
628	} else {
629	if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
630	btrfs_set_extent_data_ref_count(eb: leaf, s: ref1, val: num_refs);
631	else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
632	btrfs_set_shared_data_ref_count(eb: leaf, s: ref2, val: num_refs);
633	btrfs_mark_buffer_dirty(trans, buf: leaf);
634	}
635	return ret;
636	}
637
638	static noinline u32 extent_data_ref_count(struct btrfs_path *path,
639	struct btrfs_extent_inline_ref *iref)
640	{
641	struct btrfs_key key;
642	struct extent_buffer *leaf;
643	struct btrfs_extent_data_ref *ref1;
644	struct btrfs_shared_data_ref *ref2;
645	u32 num_refs = 0;
646	int type;
647
648	leaf = path->nodes[0];
649	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
650
651	if (iref) {
652	/*
653	* If type is invalid, we should have bailed out earlier than
654	* this call.
655	*/
656	type = btrfs_get_extent_inline_ref_type(eb: leaf, iref, is_data: BTRFS_REF_TYPE_DATA);
657	ASSERT(type != BTRFS_REF_TYPE_INVALID);
658	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
659	ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
660	num_refs = btrfs_extent_data_ref_count(eb: leaf, s: ref1);
661	} else {
662	ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
663	num_refs = btrfs_shared_data_ref_count(eb: leaf, s: ref2);
664	}
665	} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
666	ref1 = btrfs_item_ptr(leaf, path->slots[0],
667	struct btrfs_extent_data_ref);
668	num_refs = btrfs_extent_data_ref_count(eb: leaf, s: ref1);
669	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
670	ref2 = btrfs_item_ptr(leaf, path->slots[0],
671	struct btrfs_shared_data_ref);
672	num_refs = btrfs_shared_data_ref_count(eb: leaf, s: ref2);
673	} else {
674	WARN_ON(1);
675	}
676	return num_refs;
677	}
678
679	static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
680	struct btrfs_path *path,
681	u64 bytenr, u64 parent,
682	u64 root_objectid)
683	{
684	struct btrfs_root *root = btrfs_extent_root(fs_info: trans->fs_info, bytenr);
685	struct btrfs_key key;
686	int ret;
687
688	key.objectid = bytenr;
689	if (parent) {
690	key.type = BTRFS_SHARED_BLOCK_REF_KEY;
691	key.offset = parent;
692	} else {
693	key.type = BTRFS_TREE_BLOCK_REF_KEY;
694	key.offset = root_objectid;
695	}
696
697	ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1);
698	if (ret > 0)
699	ret = -ENOENT;
700	return ret;
701	}
702
703	static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
704	struct btrfs_path *path,
705	u64 bytenr, u64 parent,
706	u64 root_objectid)
707	{
708	struct btrfs_root *root = btrfs_extent_root(fs_info: trans->fs_info, bytenr);
709	struct btrfs_key key;
710	int ret;
711
712	key.objectid = bytenr;
713	if (parent) {
714	key.type = BTRFS_SHARED_BLOCK_REF_KEY;
715	key.offset = parent;
716	} else {
717	key.type = BTRFS_TREE_BLOCK_REF_KEY;
718	key.offset = root_objectid;
719	}
720
721	ret = btrfs_insert_empty_item(trans, root, path, key: &key, data_size: 0);
722	btrfs_release_path(p: path);
723	return ret;
724	}
725
726	static inline int extent_ref_type(u64 parent, u64 owner)
727	{
728	int type;
729	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
730	if (parent > 0)
731	type = BTRFS_SHARED_BLOCK_REF_KEY;
732	else
733	type = BTRFS_TREE_BLOCK_REF_KEY;
734	} else {
735	if (parent > 0)
736	type = BTRFS_SHARED_DATA_REF_KEY;
737	else
738	type = BTRFS_EXTENT_DATA_REF_KEY;
739	}
740	return type;
741	}
742
743	static int find_next_key(struct btrfs_path *path, int level,
744	struct btrfs_key *key)
745
746	{
747	for (; level < BTRFS_MAX_LEVEL; level++) {
748	if (!path->nodes[level])
749	break;
750	if (path->slots[level] + 1 >=
751	btrfs_header_nritems(eb: path->nodes[level]))
752	continue;
753	if (level == 0)
754	btrfs_item_key_to_cpu(eb: path->nodes[level], cpu_key: key,
755	nr: path->slots[level] + 1);
756	else
757	btrfs_node_key_to_cpu(eb: path->nodes[level], cpu_key: key,
758	nr: path->slots[level] + 1);
759	return 0;
760	}
761	return 1;
762	}
763
764	/*
765	* look for inline back ref. if back ref is found, *ref_ret is set
766	* to the address of inline back ref, and 0 is returned.
767	*
768	* if back ref isn't found, *ref_ret is set to the address where it
769	* should be inserted, and -ENOENT is returned.
770	*
771	* if insert is true and there are too many inline back refs, the path
772	* points to the extent item, and -EAGAIN is returned.
773	*
774	* NOTE: inline back refs are ordered in the same way that back ref
775	* items in the tree are ordered.
776	*/
777	static noinline_for_stack
778	int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
779	struct btrfs_path *path,
780	struct btrfs_extent_inline_ref **ref_ret,
781	u64 bytenr, u64 num_bytes,
782	u64 parent, u64 root_objectid,
783	u64 owner, u64 offset, int insert)
784	{
785	struct btrfs_fs_info *fs_info = trans->fs_info;
786	struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr);
787	struct btrfs_key key;
788	struct extent_buffer *leaf;
789	struct btrfs_extent_item *ei;
790	struct btrfs_extent_inline_ref *iref;
791	u64 flags;
792	u64 item_size;
793	unsigned long ptr;
794	unsigned long end;
795	int extra_size;
796	int type;
797	int want;
798	int ret;
799	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
800	int needed;
801
802	key.objectid = bytenr;
803	key.type = BTRFS_EXTENT_ITEM_KEY;
804	key.offset = num_bytes;
805
806	want = extent_ref_type(parent, owner);
807	if (insert) {
808	extra_size = btrfs_extent_inline_ref_size(type: want);
809	path->search_for_extension = 1;
810	path->keep_locks = 1;
811	} else
812	extra_size = -1;
813
814	/*
815	* Owner is our level, so we can just add one to get the level for the
816	* block we are interested in.
817	*/
818	if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
819	key.type = BTRFS_METADATA_ITEM_KEY;
820	key.offset = owner;
821	}
822
823	again:
824	ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: extra_size, cow: 1);
825	if (ret < 0)
826	goto out;
827
828	/*
829	* We may be a newly converted file system which still has the old fat
830	* extent entries for metadata, so try and see if we have one of those.
831	*/
832	if (ret > 0 && skinny_metadata) {
833	skinny_metadata = false;
834	if (path->slots[0]) {
835	path->slots[0]--;
836	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key,
837	nr: path->slots[0]);
838	if (key.objectid == bytenr &&
839	key.type == BTRFS_EXTENT_ITEM_KEY &&
840	key.offset == num_bytes)
841	ret = 0;
842	}
843	if (ret) {
844	key.objectid = bytenr;
845	key.type = BTRFS_EXTENT_ITEM_KEY;
846	key.offset = num_bytes;
847	btrfs_release_path(p: path);
848	goto again;
849	}
850	}
851
852	if (ret && !insert) {
853	ret = -ENOENT;
854	goto out;
855	} else if (WARN_ON(ret)) {
856	btrfs_print_leaf(l: path->nodes[0]);
857	btrfs_err(fs_info,
858	"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",
859	bytenr, num_bytes, parent, root_objectid, owner,
860	offset);
861	ret = -EUCLEAN;
862	goto out;
863	}
864
865	leaf = path->nodes[0];
866	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
867	if (unlikely(item_size < sizeof(*ei))) {
868	ret = -EUCLEAN;
869	btrfs_err(fs_info,
870	"unexpected extent item size, has %llu expect >= %zu",
871	item_size, sizeof(*ei));
872	btrfs_abort_transaction(trans, ret);
873	goto out;
874	}
875
876	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
877	flags = btrfs_extent_flags(eb: leaf, s: ei);
878
879	ptr = (unsigned long)(ei + 1);
880	end = (unsigned long)ei + item_size;
881
882	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
883	ptr += sizeof(struct btrfs_tree_block_info);
884	BUG_ON(ptr > end);
885	}
886
887	if (owner >= BTRFS_FIRST_FREE_OBJECTID)
888	needed = BTRFS_REF_TYPE_DATA;
889	else
890	needed = BTRFS_REF_TYPE_BLOCK;
891
892	ret = -ENOENT;
893	while (ptr < end) {
894	iref = (struct btrfs_extent_inline_ref *)ptr;
895	type = btrfs_get_extent_inline_ref_type(eb: leaf, iref, is_data: needed);
896	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
897	ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
898	ptr += btrfs_extent_inline_ref_size(type);
899	continue;
900	}
901	if (type == BTRFS_REF_TYPE_INVALID) {
902	ret = -EUCLEAN;
903	goto out;
904	}
905
906	if (want < type)
907	break;
908	if (want > type) {
909	ptr += btrfs_extent_inline_ref_size(type);
910	continue;
911	}
912
913	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
914	struct btrfs_extent_data_ref *dref;
915	dref = (struct btrfs_extent_data_ref *)(&iref->offset);
916	if (match_extent_data_ref(leaf, ref: dref, root_objectid,
917	owner, offset)) {
918	ret = 0;
919	break;
920	}
921	if (hash_extent_data_ref_item(leaf, ref: dref) <
922	hash_extent_data_ref(root_objectid, owner, offset))
923	break;
924	} else {
925	u64 ref_offset;
926	ref_offset = btrfs_extent_inline_ref_offset(eb: leaf, s: iref);
927	if (parent > 0) {
928	if (parent == ref_offset) {
929	ret = 0;
930	break;
931	}
932	if (ref_offset < parent)
933	break;
934	} else {
935	if (root_objectid == ref_offset) {
936	ret = 0;
937	break;
938	}
939	if (ref_offset < root_objectid)
940	break;
941	}
942	}
943	ptr += btrfs_extent_inline_ref_size(type);
944	}
945
946	if (unlikely(ptr > end)) {
947	ret = -EUCLEAN;
948	btrfs_print_leaf(l: path->nodes[0]);
949	btrfs_crit(fs_info,
950	"overrun extent record at slot %d while looking for inline extent for root %llu owner %llu offset %llu parent %llu",
951	path->slots[0], root_objectid, owner, offset, parent);
952	goto out;
953	}
954
955	if (ret == -ENOENT && insert) {
956	if (item_size + extra_size >=
957	BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
958	ret = -EAGAIN;
959	goto out;
960	}
961	/*
962	* To add new inline back ref, we have to make sure
963	* there is no corresponding back ref item.
964	* For simplicity, we just do not add new inline back
965	* ref if there is any kind of item for this block
966	*/
967	if (find_next_key(path, level: 0, key: &key) == 0 &&
968	key.objectid == bytenr &&
969	key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
970	ret = -EAGAIN;
971	goto out;
972	}
973	}
974	*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
975	out:
976	if (insert) {
977	path->keep_locks = 0;
978	path->search_for_extension = 0;
979	btrfs_unlock_up_safe(path, level: 1);
980	}
981	return ret;
982	}
983
984	/*
985	* helper to add new inline back ref
986	*/
987	static noinline_for_stack
988	void setup_inline_extent_backref(struct btrfs_trans_handle *trans,
989	struct btrfs_path *path,
990	struct btrfs_extent_inline_ref *iref,
991	u64 parent, u64 root_objectid,
992	u64 owner, u64 offset, int refs_to_add,
993	struct btrfs_delayed_extent_op *extent_op)
994	{
995	struct extent_buffer *leaf;
996	struct btrfs_extent_item *ei;
997	unsigned long ptr;
998	unsigned long end;
999	unsigned long item_offset;
1000	u64 refs;
1001	int size;
1002	int type;
1003
1004	leaf = path->nodes[0];
1005	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1006	item_offset = (unsigned long)iref - (unsigned long)ei;
1007
1008	type = extent_ref_type(parent, owner);
1009	size = btrfs_extent_inline_ref_size(type);
1010
1011	btrfs_extend_item(trans, path, data_size: size);
1012
1013	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1014	refs = btrfs_extent_refs(eb: leaf, s: ei);
1015	refs += refs_to_add;
1016	btrfs_set_extent_refs(eb: leaf, s: ei, val: refs);
1017	if (extent_op)
1018	__run_delayed_extent_op(extent_op, leaf, ei);
1019
1020	ptr = (unsigned long)ei + item_offset;
1021	end = (unsigned long)ei + btrfs_item_size(eb: leaf, slot: path->slots[0]);
1022	if (ptr < end - size)
1023	memmove_extent_buffer(dst: leaf, dst_offset: ptr + size, src_offset: ptr,
1024	len: end - size - ptr);
1025
1026	iref = (struct btrfs_extent_inline_ref *)ptr;
1027	btrfs_set_extent_inline_ref_type(eb: leaf, s: iref, val: type);
1028	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1029	struct btrfs_extent_data_ref *dref;
1030	dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1031	btrfs_set_extent_data_ref_root(eb: leaf, s: dref, val: root_objectid);
1032	btrfs_set_extent_data_ref_objectid(eb: leaf, s: dref, val: owner);
1033	btrfs_set_extent_data_ref_offset(eb: leaf, s: dref, val: offset);
1034	btrfs_set_extent_data_ref_count(eb: leaf, s: dref, val: refs_to_add);
1035	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1036	struct btrfs_shared_data_ref *sref;
1037	sref = (struct btrfs_shared_data_ref *)(iref + 1);
1038	btrfs_set_shared_data_ref_count(eb: leaf, s: sref, val: refs_to_add);
1039	btrfs_set_extent_inline_ref_offset(eb: leaf, s: iref, val: parent);
1040	} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1041	btrfs_set_extent_inline_ref_offset(eb: leaf, s: iref, val: parent);
1042	} else {
1043	btrfs_set_extent_inline_ref_offset(eb: leaf, s: iref, val: root_objectid);
1044	}
1045	btrfs_mark_buffer_dirty(trans, buf: leaf);
1046	}
1047
1048	static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1049	struct btrfs_path *path,
1050	struct btrfs_extent_inline_ref **ref_ret,
1051	u64 bytenr, u64 num_bytes, u64 parent,
1052	u64 root_objectid, u64 owner, u64 offset)
1053	{
1054	int ret;
1055
1056	ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1057	num_bytes, parent, root_objectid,
1058	owner, offset, insert: 0);
1059	if (ret != -ENOENT)
1060	return ret;
1061
1062	btrfs_release_path(p: path);
1063	*ref_ret = NULL;
1064
1065	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1066	ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1067	root_objectid);
1068	} else {
1069	ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1070	root_objectid, owner, offset);
1071	}
1072	return ret;
1073	}
1074
1075	/*
1076	* helper to update/remove inline back ref
1077	*/
1078	static noinline_for_stack int update_inline_extent_backref(
1079	struct btrfs_trans_handle *trans,
1080	struct btrfs_path *path,
1081	struct btrfs_extent_inline_ref *iref,
1082	int refs_to_mod,
1083	struct btrfs_delayed_extent_op *extent_op)
1084	{
1085	struct extent_buffer *leaf = path->nodes[0];
1086	struct btrfs_fs_info *fs_info = leaf->fs_info;
1087	struct btrfs_extent_item *ei;
1088	struct btrfs_extent_data_ref *dref = NULL;
1089	struct btrfs_shared_data_ref *sref = NULL;
1090	unsigned long ptr;
1091	unsigned long end;
1092	u32 item_size;
1093	int size;
1094	int type;
1095	u64 refs;
1096
1097	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1098	refs = btrfs_extent_refs(eb: leaf, s: ei);
1099	if (unlikely(refs_to_mod < 0 && refs + refs_to_mod <= 0)) {
1100	struct btrfs_key key;
1101	u32 extent_size;
1102
1103	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
1104	if (key.type == BTRFS_METADATA_ITEM_KEY)
1105	extent_size = fs_info->nodesize;
1106	else
1107	extent_size = key.offset;
1108	btrfs_print_leaf(l: leaf);
1109	btrfs_err(fs_info,
1110	"invalid refs_to_mod for extent %llu num_bytes %u, has %d expect >= -%llu",
1111	key.objectid, extent_size, refs_to_mod, refs);
1112	return -EUCLEAN;
1113	}
1114	refs += refs_to_mod;
1115	btrfs_set_extent_refs(eb: leaf, s: ei, val: refs);
1116	if (extent_op)
1117	__run_delayed_extent_op(extent_op, leaf, ei);
1118
1119	type = btrfs_get_extent_inline_ref_type(eb: leaf, iref, is_data: BTRFS_REF_TYPE_ANY);
1120	/*
1121	* Function btrfs_get_extent_inline_ref_type() has already printed
1122	* error messages.
1123	*/
1124	if (unlikely(type == BTRFS_REF_TYPE_INVALID))
1125	return -EUCLEAN;
1126
1127	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1128	dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1129	refs = btrfs_extent_data_ref_count(eb: leaf, s: dref);
1130	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1131	sref = (struct btrfs_shared_data_ref *)(iref + 1);
1132	refs = btrfs_shared_data_ref_count(eb: leaf, s: sref);
1133	} else {
1134	refs = 1;
1135	/*
1136	* For tree blocks we can only drop one ref for it, and tree
1137	* blocks should not have refs > 1.
1138	*
1139	* Furthermore if we're inserting a new inline backref, we
1140	* won't reach this path either. That would be
1141	* setup_inline_extent_backref().
1142	*/
1143	if (unlikely(refs_to_mod != -1)) {
1144	struct btrfs_key key;
1145
1146	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
1147
1148	btrfs_print_leaf(l: leaf);
1149	btrfs_err(fs_info,
1150	"invalid refs_to_mod for tree block %llu, has %d expect -1",
1151	key.objectid, refs_to_mod);
1152	return -EUCLEAN;
1153	}
1154	}
1155
1156	if (unlikely(refs_to_mod < 0 && refs < -refs_to_mod)) {
1157	struct btrfs_key key;
1158	u32 extent_size;
1159
1160	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
1161	if (key.type == BTRFS_METADATA_ITEM_KEY)
1162	extent_size = fs_info->nodesize;
1163	else
1164	extent_size = key.offset;
1165	btrfs_print_leaf(l: leaf);
1166	btrfs_err(fs_info,
1167	"invalid refs_to_mod for backref entry, iref %lu extent %llu num_bytes %u, has %d expect >= -%llu",
1168	(unsigned long)iref, key.objectid, extent_size,
1169	refs_to_mod, refs);
1170	return -EUCLEAN;
1171	}
1172	refs += refs_to_mod;
1173
1174	if (refs > 0) {
1175	if (type == BTRFS_EXTENT_DATA_REF_KEY)
1176	btrfs_set_extent_data_ref_count(eb: leaf, s: dref, val: refs);
1177	else
1178	btrfs_set_shared_data_ref_count(eb: leaf, s: sref, val: refs);
1179	} else {
1180	size = btrfs_extent_inline_ref_size(type);
1181	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
1182	ptr = (unsigned long)iref;
1183	end = (unsigned long)ei + item_size;
1184	if (ptr + size < end)
1185	memmove_extent_buffer(dst: leaf, dst_offset: ptr, src_offset: ptr + size,
1186	len: end - ptr - size);
1187	item_size -= size;
1188	btrfs_truncate_item(trans, path, new_size: item_size, from_end: 1);
1189	}
1190	btrfs_mark_buffer_dirty(trans, buf: leaf);
1191	return 0;
1192	}
1193
1194	static noinline_for_stack
1195	int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1196	struct btrfs_path *path,
1197	u64 bytenr, u64 num_bytes, u64 parent,
1198	u64 root_objectid, u64 owner,
1199	u64 offset, int refs_to_add,
1200	struct btrfs_delayed_extent_op *extent_op)
1201	{
1202	struct btrfs_extent_inline_ref *iref;
1203	int ret;
1204
1205	ret = lookup_inline_extent_backref(trans, path, ref_ret: &iref, bytenr,
1206	num_bytes, parent, root_objectid,
1207	owner, offset, insert: 1);
1208	if (ret == 0) {
1209	/*
1210	* We're adding refs to a tree block we already own, this
1211	* should not happen at all.
1212	*/
1213	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1214	btrfs_print_leaf(l: path->nodes[0]);
1215	btrfs_crit(trans->fs_info,
1216	"adding refs to an existing tree ref, bytenr %llu num_bytes %llu root_objectid %llu slot %u",
1217	bytenr, num_bytes, root_objectid, path->slots[0]);
1218	return -EUCLEAN;
1219	}
1220	ret = update_inline_extent_backref(trans, path, iref,
1221	refs_to_mod: refs_to_add, extent_op);
1222	} else if (ret == -ENOENT) {
1223	setup_inline_extent_backref(trans, path, iref, parent,
1224	root_objectid, owner, offset,
1225	refs_to_add, extent_op);
1226	ret = 0;
1227	}
1228	return ret;
1229	}
1230
1231	static int remove_extent_backref(struct btrfs_trans_handle *trans,
1232	struct btrfs_root *root,
1233	struct btrfs_path *path,
1234	struct btrfs_extent_inline_ref *iref,
1235	int refs_to_drop, int is_data)
1236	{
1237	int ret = 0;
1238
1239	BUG_ON(!is_data && refs_to_drop != 1);
1240	if (iref)
1241	ret = update_inline_extent_backref(trans, path, iref,
1242	refs_to_mod: -refs_to_drop, NULL);
1243	else if (is_data)
1244	ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1245	else
1246	ret = btrfs_del_item(trans, root, path);
1247	return ret;
1248	}
1249
1250	static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1251	u64 *discarded_bytes)
1252	{
1253	int j, ret = 0;
1254	u64 bytes_left, end;
1255	u64 aligned_start = ALIGN(start, 1 << SECTOR_SHIFT);
1256
1257	if (WARN_ON(start != aligned_start)) {
1258	len -= aligned_start - start;
1259	len = round_down(len, 1 << SECTOR_SHIFT);
1260	start = aligned_start;
1261	}
1262
1263	*discarded_bytes = 0;
1264
1265	if (!len)
1266	return 0;
1267
1268	end = start + len;
1269	bytes_left = len;
1270
1271	/* Skip any superblocks on this device. */
1272	for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1273	u64 sb_start = btrfs_sb_offset(mirror: j);
1274	u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1275	u64 size = sb_start - start;
1276
1277	if (!in_range(sb_start, start, bytes_left) &&
1278	!in_range(sb_end, start, bytes_left) &&
1279	!in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1280	continue;
1281
1282	/*
1283	* Superblock spans beginning of range. Adjust start and
1284	* try again.
1285	*/
1286	if (sb_start <= start) {
1287	start += sb_end - start;
1288	if (start > end) {
1289	bytes_left = 0;
1290	break;
1291	}
1292	bytes_left = end - start;
1293	continue;
1294	}
1295
1296	if (size) {
1297	ret = blkdev_issue_discard(bdev, sector: start >> SECTOR_SHIFT,
1298	nr_sects: size >> SECTOR_SHIFT,
1299	GFP_NOFS);
1300	if (!ret)
1301	*discarded_bytes += size;
1302	else if (ret != -EOPNOTSUPP)
1303	return ret;
1304	}
1305
1306	start = sb_end;
1307	if (start > end) {
1308	bytes_left = 0;
1309	break;
1310	}
1311	bytes_left = end - start;
1312	}
1313
1314	if (bytes_left) {
1315	ret = blkdev_issue_discard(bdev, sector: start >> SECTOR_SHIFT,
1316	nr_sects: bytes_left >> SECTOR_SHIFT,
1317	GFP_NOFS);
1318	if (!ret)
1319	*discarded_bytes += bytes_left;
1320	}
1321	return ret;
1322	}
1323
1324	static int do_discard_extent(struct btrfs_discard_stripe *stripe, u64 *bytes)
1325	{
1326	struct btrfs_device *dev = stripe->dev;
1327	struct btrfs_fs_info *fs_info = dev->fs_info;
1328	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1329	u64 phys = stripe->physical;
1330	u64 len = stripe->length;
1331	u64 discarded = 0;
1332	int ret = 0;
1333
1334	/* Zone reset on a zoned filesystem */
1335	if (btrfs_can_zone_reset(device: dev, physical: phys, length: len)) {
1336	u64 src_disc;
1337
1338	ret = btrfs_reset_device_zone(device: dev, physical: phys, length: len, bytes: &discarded);
1339	if (ret)
1340	goto out;
1341
1342	if (!btrfs_dev_replace_is_ongoing(dev_replace) ||
1343	dev != dev_replace->srcdev)
1344	goto out;
1345
1346	src_disc = discarded;
1347
1348	/* Send to replace target as well */
1349	ret = btrfs_reset_device_zone(device: dev_replace->tgtdev, physical: phys, length: len,
1350	bytes: &discarded);
1351	discarded += src_disc;
1352	} else if (bdev_max_discard_sectors(bdev: stripe->dev->bdev)) {
1353	ret = btrfs_issue_discard(bdev: dev->bdev, start: phys, len, discarded_bytes: &discarded);
1354	} else {
1355	ret = 0;
1356	*bytes = 0;
1357	}
1358
1359	out:
1360	*bytes = discarded;
1361	return ret;
1362	}
1363
1364	int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1365	u64 num_bytes, u64 *actual_bytes)
1366	{
1367	int ret = 0;
1368	u64 discarded_bytes = 0;
1369	u64 end = bytenr + num_bytes;
1370	u64 cur = bytenr;
1371
1372	/*
1373	* Avoid races with device replace and make sure the devices in the
1374	* stripes don't go away while we are discarding.
1375	*/
1376	btrfs_bio_counter_inc_blocked(fs_info);
1377	while (cur < end) {
1378	struct btrfs_discard_stripe *stripes;
1379	unsigned int num_stripes;
1380	int i;
1381
1382	num_bytes = end - cur;
1383	stripes = btrfs_map_discard(fs_info, logical: cur, length_ret: &num_bytes, num_stripes: &num_stripes);
1384	if (IS_ERR(ptr: stripes)) {
1385	ret = PTR_ERR(ptr: stripes);
1386	if (ret == -EOPNOTSUPP)
1387	ret = 0;
1388	break;
1389	}
1390
1391	for (i = 0; i < num_stripes; i++) {
1392	struct btrfs_discard_stripe *stripe = stripes + i;
1393	u64 bytes;
1394
1395	if (!stripe->dev->bdev) {
1396	ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1397	continue;
1398	}
1399
1400	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE,
1401	&stripe->dev->dev_state))
1402	continue;
1403
1404	ret = do_discard_extent(stripe, bytes: &bytes);
1405	if (ret) {
1406	/*
1407	* Keep going if discard is not supported by the
1408	* device.
1409	*/
1410	if (ret != -EOPNOTSUPP)
1411	break;
1412	ret = 0;
1413	} else {
1414	discarded_bytes += bytes;
1415	}
1416	}
1417	kfree(objp: stripes);
1418	if (ret)
1419	break;
1420	cur += num_bytes;
1421	}
1422	btrfs_bio_counter_dec(fs_info);
1423	if (actual_bytes)
1424	*actual_bytes = discarded_bytes;
1425	return ret;
1426	}
1427
1428	/* Can return -ENOMEM */
1429	int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1430	struct btrfs_ref *generic_ref)
1431	{
1432	struct btrfs_fs_info *fs_info = trans->fs_info;
1433	int ret;
1434
1435	ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
1436	generic_ref->action);
1437	BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
1438	generic_ref->tree_ref.ref_root == BTRFS_TREE_LOG_OBJECTID);
1439
1440	if (generic_ref->type == BTRFS_REF_METADATA)
1441	ret = btrfs_add_delayed_tree_ref(trans, generic_ref, NULL);
1442	else
1443	ret = btrfs_add_delayed_data_ref(trans, generic_ref, reserved: 0);
1444
1445	btrfs_ref_tree_mod(fs_info, generic_ref);
1446
1447	return ret;
1448	}
1449
1450	/*
1451	* Insert backreference for a given extent.
1452	*
1453	* The counterpart is in __btrfs_free_extent(), with examples and more details
1454	* how it works.
1455	*
1456	* @trans: Handle of transaction
1457	*
1458	* @node: The delayed ref node used to get the bytenr/length for
1459	* extent whose references are incremented.
1460	*
1461	* @parent: If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
1462	* BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
1463	* bytenr of the parent block. Since new extents are always
1464	* created with indirect references, this will only be the case
1465	* when relocating a shared extent. In that case, root_objectid
1466	* will be BTRFS_TREE_RELOC_OBJECTID. Otherwise, parent must
1467	* be 0
1468	*
1469	* @root_objectid: The id of the root where this modification has originated,
1470	* this can be either one of the well-known metadata trees or
1471	* the subvolume id which references this extent.
1472	*
1473	* @owner: For data extents it is the inode number of the owning file.
1474	* For metadata extents this parameter holds the level in the
1475	* tree of the extent.
1476	*
1477	* @offset: For metadata extents the offset is ignored and is currently
1478	* always passed as 0. For data extents it is the fileoffset
1479	* this extent belongs to.
1480	*
1481	* @extent_op Pointer to a structure, holding information necessary when
1482	* updating a tree block's flags
1483	*
1484	*/
1485	static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1486	struct btrfs_delayed_ref_node *node,
1487	u64 parent, u64 root_objectid,
1488	u64 owner, u64 offset,
1489	struct btrfs_delayed_extent_op *extent_op)
1490	{
1491	struct btrfs_path *path;
1492	struct extent_buffer *leaf;
1493	struct btrfs_extent_item *item;
1494	struct btrfs_key key;
1495	u64 bytenr = node->bytenr;
1496	u64 num_bytes = node->num_bytes;
1497	u64 refs;
1498	int refs_to_add = node->ref_mod;
1499	int ret;
1500
1501	path = btrfs_alloc_path();
1502	if (!path)
1503	return -ENOMEM;
1504
1505	/* this will setup the path even if it fails to insert the back ref */
1506	ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
1507	parent, root_objectid, owner,
1508	offset, refs_to_add, extent_op);
1509	if ((ret < 0 && ret != -EAGAIN) || !ret)
1510	goto out;
1511
1512	/*
1513	* Ok we had -EAGAIN which means we didn't have space to insert and
1514	* inline extent ref, so just update the reference count and add a
1515	* normal backref.
1516	*/
1517	leaf = path->nodes[0];
1518	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
1519	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1520	refs = btrfs_extent_refs(eb: leaf, s: item);
1521	btrfs_set_extent_refs(eb: leaf, s: item, val: refs + refs_to_add);
1522	if (extent_op)
1523	__run_delayed_extent_op(extent_op, leaf, ei: item);
1524
1525	btrfs_mark_buffer_dirty(trans, buf: leaf);
1526	btrfs_release_path(p: path);
1527
1528	/* now insert the actual backref */
1529	if (owner < BTRFS_FIRST_FREE_OBJECTID)
1530	ret = insert_tree_block_ref(trans, path, bytenr, parent,
1531	root_objectid);
1532	else
1533	ret = insert_extent_data_ref(trans, path, bytenr, parent,
1534	root_objectid, owner, offset,
1535	refs_to_add);
1536
1537	if (ret)
1538	btrfs_abort_transaction(trans, ret);
1539	out:
1540	btrfs_free_path(p: path);
1541	return ret;
1542	}
1543
1544	static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1545	struct btrfs_delayed_ref_head *href,
1546	struct btrfs_delayed_ref_node *node,
1547	struct btrfs_delayed_extent_op *extent_op,
1548	bool insert_reserved)
1549	{
1550	int ret = 0;
1551	struct btrfs_delayed_data_ref *ref;
1552	u64 parent = 0;
1553	u64 flags = 0;
1554
1555	ref = btrfs_delayed_node_to_data_ref(node);
1556	trace_run_delayed_data_ref(fs_info: trans->fs_info, ref: node, full_ref: ref, action: node->action);
1557
1558	if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1559	parent = ref->parent;
1560
1561	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1562	struct btrfs_key key;
1563	struct btrfs_squota_delta delta = {
1564	.root = href->owning_root,
1565	.num_bytes = node->num_bytes,
1566	.rsv_bytes = href->reserved_bytes,
1567	.is_data = true,
1568	.is_inc = true,
1569	.generation = trans->transid,
1570	};
1571
1572	if (extent_op)
1573	flags |= extent_op->flags_to_set;
1574
1575	key.objectid = node->bytenr;
1576	key.type = BTRFS_EXTENT_ITEM_KEY;
1577	key.offset = node->num_bytes;
1578
1579	ret = alloc_reserved_file_extent(trans, parent, root_objectid: ref->root,
1580	flags, owner: ref->objectid,
1581	offset: ref->offset, ins: &key,
1582	ref_mod: node->ref_mod, oref_root: href->owning_root);
1583	if (!ret)
1584	ret = btrfs_record_squota_delta(fs_info: trans->fs_info, delta: &delta);
1585	else
1586	btrfs_qgroup_free_refroot(fs_info: trans->fs_info, ref_root: delta.root,
1587	num_bytes: delta.rsv_bytes, type: BTRFS_QGROUP_RSV_DATA);
1588	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
1589	ret = __btrfs_inc_extent_ref(trans, node, parent, root_objectid: ref->root,
1590	owner: ref->objectid, offset: ref->offset,
1591	extent_op);
1592	} else if (node->action == BTRFS_DROP_DELAYED_REF) {
1593	ret = __btrfs_free_extent(trans, href, node, parent,
1594	root_objectid: ref->root, owner_objectid: ref->objectid,
1595	owner_offset: ref->offset, extra_op: extent_op);
1596	} else {
1597	BUG();
1598	}
1599	return ret;
1600	}
1601
1602	static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1603	struct extent_buffer *leaf,
1604	struct btrfs_extent_item *ei)
1605	{
1606	u64 flags = btrfs_extent_flags(eb: leaf, s: ei);
1607	if (extent_op->update_flags) {
1608	flags |= extent_op->flags_to_set;
1609	btrfs_set_extent_flags(eb: leaf, s: ei, val: flags);
1610	}
1611
1612	if (extent_op->update_key) {
1613	struct btrfs_tree_block_info *bi;
1614	BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1615	bi = (struct btrfs_tree_block_info *)(ei + 1);
1616	btrfs_set_tree_block_key(eb: leaf, item: bi, key: &extent_op->key);
1617	}
1618	}
1619
1620	static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1621	struct btrfs_delayed_ref_head *head,
1622	struct btrfs_delayed_extent_op *extent_op)
1623	{
1624	struct btrfs_fs_info *fs_info = trans->fs_info;
1625	struct btrfs_root *root;
1626	struct btrfs_key key;
1627	struct btrfs_path *path;
1628	struct btrfs_extent_item *ei;
1629	struct extent_buffer *leaf;
1630	u32 item_size;
1631	int ret;
1632	int metadata = 1;
1633
1634	if (TRANS_ABORTED(trans))
1635	return 0;
1636
1637	if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1638	metadata = 0;
1639
1640	path = btrfs_alloc_path();
1641	if (!path)
1642	return -ENOMEM;
1643
1644	key.objectid = head->bytenr;
1645
1646	if (metadata) {
1647	key.type = BTRFS_METADATA_ITEM_KEY;
1648	key.offset = extent_op->level;
1649	} else {
1650	key.type = BTRFS_EXTENT_ITEM_KEY;
1651	key.offset = head->num_bytes;
1652	}
1653
1654	root = btrfs_extent_root(fs_info, bytenr: key.objectid);
1655	again:
1656	ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: 0, cow: 1);
1657	if (ret < 0) {
1658	goto out;
1659	} else if (ret > 0) {
1660	if (metadata) {
1661	if (path->slots[0] > 0) {
1662	path->slots[0]--;
1663	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key,
1664	nr: path->slots[0]);
1665	if (key.objectid == head->bytenr &&
1666	key.type == BTRFS_EXTENT_ITEM_KEY &&
1667	key.offset == head->num_bytes)
1668	ret = 0;
1669	}
1670	if (ret > 0) {
1671	btrfs_release_path(p: path);
1672	metadata = 0;
1673
1674	key.objectid = head->bytenr;
1675	key.offset = head->num_bytes;
1676	key.type = BTRFS_EXTENT_ITEM_KEY;
1677	goto again;
1678	}
1679	} else {
1680	ret = -EUCLEAN;
1681	btrfs_err(fs_info,
1682	"missing extent item for extent %llu num_bytes %llu level %d",
1683	head->bytenr, head->num_bytes, extent_op->level);
1684	goto out;
1685	}
1686	}
1687
1688	leaf = path->nodes[0];
1689	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
1690
1691	if (unlikely(item_size < sizeof(*ei))) {
1692	ret = -EUCLEAN;
1693	btrfs_err(fs_info,
1694	"unexpected extent item size, has %u expect >= %zu",
1695	item_size, sizeof(*ei));
1696	btrfs_abort_transaction(trans, ret);
1697	goto out;
1698	}
1699
1700	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1701	__run_delayed_extent_op(extent_op, leaf, ei);
1702
1703	btrfs_mark_buffer_dirty(trans, buf: leaf);
1704	out:
1705	btrfs_free_path(p: path);
1706	return ret;
1707	}
1708
1709	static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1710	struct btrfs_delayed_ref_head *href,
1711	struct btrfs_delayed_ref_node *node,
1712	struct btrfs_delayed_extent_op *extent_op,
1713	bool insert_reserved)
1714	{
1715	int ret = 0;
1716	struct btrfs_fs_info *fs_info = trans->fs_info;
1717	struct btrfs_delayed_tree_ref *ref;
1718	u64 parent = 0;
1719	u64 ref_root = 0;
1720
1721	ref = btrfs_delayed_node_to_tree_ref(node);
1722	trace_run_delayed_tree_ref(fs_info: trans->fs_info, ref: node, full_ref: ref, action: node->action);
1723
1724	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1725	parent = ref->parent;
1726	ref_root = ref->root;
1727
1728	if (unlikely(node->ref_mod != 1)) {
1729	btrfs_err(trans->fs_info,
1730	"btree block %llu has %d references rather than 1: action %d ref_root %llu parent %llu",
1731	node->bytenr, node->ref_mod, node->action, ref_root,
1732	parent);
1733	return -EUCLEAN;
1734	}
1735	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1736	struct btrfs_squota_delta delta = {
1737	.root = href->owning_root,
1738	.num_bytes = fs_info->nodesize,
1739	.rsv_bytes = 0,
1740	.is_data = false,
1741	.is_inc = true,
1742	.generation = trans->transid,
1743	};
1744
1745	BUG_ON(!extent_op || !extent_op->update_flags);
1746	ret = alloc_reserved_tree_block(trans, node, extent_op);
1747	if (!ret)
1748	btrfs_record_squota_delta(fs_info, delta: &delta);
1749	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
1750	ret = __btrfs_inc_extent_ref(trans, node, parent, root_objectid: ref_root,
1751	owner: ref->level, offset: 0, extent_op);
1752	} else if (node->action == BTRFS_DROP_DELAYED_REF) {
1753	ret = __btrfs_free_extent(trans, href, node, parent, root_objectid: ref_root,
1754	owner_objectid: ref->level, owner_offset: 0, extra_op: extent_op);
1755	} else {
1756	BUG();
1757	}
1758	return ret;
1759	}
1760
1761	/* helper function to actually process a single delayed ref entry */
1762	static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1763	struct btrfs_delayed_ref_head *href,
1764	struct btrfs_delayed_ref_node *node,
1765	struct btrfs_delayed_extent_op *extent_op,
1766	bool insert_reserved)
1767	{
1768	int ret = 0;
1769
1770	if (TRANS_ABORTED(trans)) {
1771	if (insert_reserved)
1772	btrfs_pin_extent(trans, bytenr: node->bytenr, num: node->num_bytes, reserved: 1);
1773	return 0;
1774	}
1775
1776	if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1777	node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1778	ret = run_delayed_tree_ref(trans, href, node, extent_op,
1779	insert_reserved);
1780	else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1781	node->type == BTRFS_SHARED_DATA_REF_KEY)
1782	ret = run_delayed_data_ref(trans, href, node, extent_op,
1783	insert_reserved);
1784	else if (node->type == BTRFS_EXTENT_OWNER_REF_KEY)
1785	ret = 0;
1786	else
1787	BUG();
1788	if (ret && insert_reserved)
1789	btrfs_pin_extent(trans, bytenr: node->bytenr, num: node->num_bytes, reserved: 1);
1790	if (ret < 0)
1791	btrfs_err(trans->fs_info,
1792	"failed to run delayed ref for logical %llu num_bytes %llu type %u action %u ref_mod %d: %d",
1793	node->bytenr, node->num_bytes, node->type,
1794	node->action, node->ref_mod, ret);
1795	return ret;
1796	}
1797
1798	static inline struct btrfs_delayed_ref_node *
1799	select_delayed_ref(struct btrfs_delayed_ref_head *head)
1800	{
1801	struct btrfs_delayed_ref_node *ref;
1802
1803	if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
1804	return NULL;
1805
1806	/*
1807	* Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
1808	* This is to prevent a ref count from going down to zero, which deletes
1809	* the extent item from the extent tree, when there still are references
1810	* to add, which would fail because they would not find the extent item.
1811	*/
1812	if (!list_empty(head: &head->ref_add_list))
1813	return list_first_entry(&head->ref_add_list,
1814	struct btrfs_delayed_ref_node, add_list);
1815
1816	ref = rb_entry(rb_first_cached(&head->ref_tree),
1817	struct btrfs_delayed_ref_node, ref_node);
1818	ASSERT(list_empty(&ref->add_list));
1819	return ref;
1820	}
1821
1822	static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
1823	struct btrfs_delayed_ref_head *head)
1824	{
1825	spin_lock(lock: &delayed_refs->lock);
1826	head->processing = false;
1827	delayed_refs->num_heads_ready++;
1828	spin_unlock(lock: &delayed_refs->lock);
1829	btrfs_delayed_ref_unlock(head);
1830	}
1831
1832	static struct btrfs_delayed_extent_op *cleanup_extent_op(
1833	struct btrfs_delayed_ref_head *head)
1834	{
1835	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
1836
1837	if (!extent_op)
1838	return NULL;
1839
1840	if (head->must_insert_reserved) {
1841	head->extent_op = NULL;
1842	btrfs_free_delayed_extent_op(op: extent_op);
1843	return NULL;
1844	}
1845	return extent_op;
1846	}
1847
1848	static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
1849	struct btrfs_delayed_ref_head *head)
1850	{
1851	struct btrfs_delayed_extent_op *extent_op;
1852	int ret;
1853
1854	extent_op = cleanup_extent_op(head);
1855	if (!extent_op)
1856	return 0;
1857	head->extent_op = NULL;
1858	spin_unlock(lock: &head->lock);
1859	ret = run_delayed_extent_op(trans, head, extent_op);
1860	btrfs_free_delayed_extent_op(op: extent_op);
1861	return ret ? ret : 1;
1862	}
1863
1864	u64 btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
1865	struct btrfs_delayed_ref_root *delayed_refs,
1866	struct btrfs_delayed_ref_head *head)
1867	{
1868	/*
1869	* We had csum deletions accounted for in our delayed refs rsv, we need
1870	* to drop the csum leaves for this update from our delayed_refs_rsv.
1871	*/
1872	if (head->total_ref_mod < 0 && head->is_data) {
1873	int nr_csums;
1874
1875	spin_lock(lock: &delayed_refs->lock);
1876	delayed_refs->pending_csums -= head->num_bytes;
1877	spin_unlock(lock: &delayed_refs->lock);
1878	nr_csums = btrfs_csum_bytes_to_leaves(fs_info, csum_bytes: head->num_bytes);
1879
1880	btrfs_delayed_refs_rsv_release(fs_info, nr_refs: 0, nr_csums);
1881
1882	return btrfs_calc_delayed_ref_csum_bytes(fs_info, num_csum_items: nr_csums);
1883	}
1884	if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE &&
1885	head->must_insert_reserved && head->is_data)
1886	btrfs_qgroup_free_refroot(fs_info, ref_root: head->owning_root,
1887	num_bytes: head->reserved_bytes, type: BTRFS_QGROUP_RSV_DATA);
1888
1889	return 0;
1890	}
1891
1892	static int cleanup_ref_head(struct btrfs_trans_handle *trans,
1893	struct btrfs_delayed_ref_head *head,
1894	u64 *bytes_released)
1895	{
1896
1897	struct btrfs_fs_info *fs_info = trans->fs_info;
1898	struct btrfs_delayed_ref_root *delayed_refs;
1899	int ret;
1900
1901	delayed_refs = &trans->transaction->delayed_refs;
1902
1903	ret = run_and_cleanup_extent_op(trans, head);
1904	if (ret < 0) {
1905	unselect_delayed_ref_head(delayed_refs, head);
1906	btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
1907	return ret;
1908	} else if (ret) {
1909	return ret;
1910	}
1911
1912	/*
1913	* Need to drop our head ref lock and re-acquire the delayed ref lock
1914	* and then re-check to make sure nobody got added.
1915	*/
1916	spin_unlock(lock: &head->lock);
1917	spin_lock(lock: &delayed_refs->lock);
1918	spin_lock(lock: &head->lock);
1919	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
1920	spin_unlock(lock: &head->lock);
1921	spin_unlock(lock: &delayed_refs->lock);
1922	return 1;
1923	}
1924	btrfs_delete_ref_head(delayed_refs, head);
1925	spin_unlock(lock: &head->lock);
1926	spin_unlock(lock: &delayed_refs->lock);
1927
1928	if (head->must_insert_reserved) {
1929	btrfs_pin_extent(trans, bytenr: head->bytenr, num: head->num_bytes, reserved: 1);
1930	if (head->is_data) {
1931	struct btrfs_root *csum_root;
1932
1933	csum_root = btrfs_csum_root(fs_info, bytenr: head->bytenr);
1934	ret = btrfs_del_csums(trans, root: csum_root, bytenr: head->bytenr,
1935	len: head->num_bytes);
1936	}
1937	}
1938
1939	*bytes_released += btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
1940
1941	trace_run_delayed_ref_head(fs_info, head_ref: head, action: 0);
1942	btrfs_delayed_ref_unlock(head);
1943	btrfs_put_delayed_ref_head(head);
1944	return ret;
1945	}
1946
1947	static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
1948	struct btrfs_trans_handle *trans)
1949	{
1950	struct btrfs_delayed_ref_root *delayed_refs =
1951	&trans->transaction->delayed_refs;
1952	struct btrfs_delayed_ref_head *head = NULL;
1953	int ret;
1954
1955	spin_lock(lock: &delayed_refs->lock);
1956	head = btrfs_select_ref_head(delayed_refs);
1957	if (!head) {
1958	spin_unlock(lock: &delayed_refs->lock);
1959	return head;
1960	}
1961
1962	/*
1963	* Grab the lock that says we are going to process all the refs for
1964	* this head
1965	*/
1966	ret = btrfs_delayed_ref_lock(delayed_refs, head);
1967	spin_unlock(lock: &delayed_refs->lock);
1968
1969	/*
1970	* We may have dropped the spin lock to get the head mutex lock, and
1971	* that might have given someone else time to free the head. If that's
1972	* true, it has been removed from our list and we can move on.
1973	*/
1974	if (ret == -EAGAIN)
1975	head = ERR_PTR(error: -EAGAIN);
1976
1977	return head;
1978	}
1979
1980	static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
1981	struct btrfs_delayed_ref_head *locked_ref,
1982	u64 *bytes_released)
1983	{
1984	struct btrfs_fs_info *fs_info = trans->fs_info;
1985	struct btrfs_delayed_ref_root *delayed_refs;
1986	struct btrfs_delayed_extent_op *extent_op;
1987	struct btrfs_delayed_ref_node *ref;
1988	bool must_insert_reserved;
1989	int ret;
1990
1991	delayed_refs = &trans->transaction->delayed_refs;
1992
1993	lockdep_assert_held(&locked_ref->mutex);
1994	lockdep_assert_held(&locked_ref->lock);
1995
1996	while ((ref = select_delayed_ref(head: locked_ref))) {
1997	if (ref->seq &&
1998	btrfs_check_delayed_seq(fs_info, seq: ref->seq)) {
1999	spin_unlock(lock: &locked_ref->lock);
2000	unselect_delayed_ref_head(delayed_refs, head: locked_ref);
2001	return -EAGAIN;
2002	}
2003
2004	rb_erase_cached(node: &ref->ref_node, root: &locked_ref->ref_tree);
2005	RB_CLEAR_NODE(&ref->ref_node);
2006	if (!list_empty(head: &ref->add_list))
2007	list_del(entry: &ref->add_list);
2008	/*
2009	* When we play the delayed ref, also correct the ref_mod on
2010	* head
2011	*/
2012	switch (ref->action) {
2013	case BTRFS_ADD_DELAYED_REF:
2014	case BTRFS_ADD_DELAYED_EXTENT:
2015	locked_ref->ref_mod -= ref->ref_mod;
2016	break;
2017	case BTRFS_DROP_DELAYED_REF:
2018	locked_ref->ref_mod += ref->ref_mod;
2019	break;
2020	default:
2021	WARN_ON(1);
2022	}
2023	atomic_dec(v: &delayed_refs->num_entries);
2024
2025	/*
2026	* Record the must_insert_reserved flag before we drop the
2027	* spin lock.
2028	*/
2029	must_insert_reserved = locked_ref->must_insert_reserved;
2030	locked_ref->must_insert_reserved = false;
2031
2032	extent_op = locked_ref->extent_op;
2033	locked_ref->extent_op = NULL;
2034	spin_unlock(lock: &locked_ref->lock);
2035
2036	ret = run_one_delayed_ref(trans, href: locked_ref, node: ref, extent_op,
2037	insert_reserved: must_insert_reserved);
2038	btrfs_delayed_refs_rsv_release(fs_info, nr_refs: 1, nr_csums: 0);
2039	*bytes_released += btrfs_calc_delayed_ref_bytes(fs_info, num_delayed_refs: 1);
2040
2041	btrfs_free_delayed_extent_op(op: extent_op);
2042	if (ret) {
2043	unselect_delayed_ref_head(delayed_refs, head: locked_ref);
2044	btrfs_put_delayed_ref(ref);
2045	return ret;
2046	}
2047
2048	btrfs_put_delayed_ref(ref);
2049	cond_resched();
2050
2051	spin_lock(lock: &locked_ref->lock);
2052	btrfs_merge_delayed_refs(fs_info, delayed_refs, head: locked_ref);
2053	}
2054
2055	return 0;
2056	}
2057
2058	/*
2059	* Returns 0 on success or if called with an already aborted transaction.
2060	* Returns -ENOMEM or -EIO on failure and will abort the transaction.
2061	*/
2062	static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2063	u64 min_bytes)
2064	{
2065	struct btrfs_fs_info *fs_info = trans->fs_info;
2066	struct btrfs_delayed_ref_root *delayed_refs;
2067	struct btrfs_delayed_ref_head *locked_ref = NULL;
2068	int ret;
2069	unsigned long count = 0;
2070	unsigned long max_count = 0;
2071	u64 bytes_processed = 0;
2072
2073	delayed_refs = &trans->transaction->delayed_refs;
2074	if (min_bytes == 0) {
2075	max_count = delayed_refs->num_heads_ready;
2076	min_bytes = U64_MAX;
2077	}
2078
2079	do {
2080	if (!locked_ref) {
2081	locked_ref = btrfs_obtain_ref_head(trans);
2082	if (IS_ERR_OR_NULL(ptr: locked_ref)) {
2083	if (PTR_ERR(ptr: locked_ref) == -EAGAIN) {
2084	continue;
2085	} else {
2086	break;
2087	}
2088	}
2089	count++;
2090	}
2091	/*
2092	* We need to try and merge add/drops of the same ref since we
2093	* can run into issues with relocate dropping the implicit ref
2094	* and then it being added back again before the drop can
2095	* finish. If we merged anything we need to re-loop so we can
2096	* get a good ref.
2097	* Or we can get node references of the same type that weren't
2098	* merged when created due to bumps in the tree mod seq, and
2099	* we need to merge them to prevent adding an inline extent
2100	* backref before dropping it (triggering a BUG_ON at
2101	* insert_inline_extent_backref()).
2102	*/
2103	spin_lock(lock: &locked_ref->lock);
2104	btrfs_merge_delayed_refs(fs_info, delayed_refs, head: locked_ref);
2105
2106	ret = btrfs_run_delayed_refs_for_head(trans, locked_ref, bytes_released: &bytes_processed);
2107	if (ret < 0 && ret != -EAGAIN) {
2108	/*
2109	* Error, btrfs_run_delayed_refs_for_head already
2110	* unlocked everything so just bail out
2111	*/
2112	return ret;
2113	} else if (!ret) {
2114	/*
2115	* Success, perform the usual cleanup of a processed
2116	* head
2117	*/
2118	ret = cleanup_ref_head(trans, head: locked_ref, bytes_released: &bytes_processed);
2119	if (ret > 0 ) {
2120	/* We dropped our lock, we need to loop. */
2121	ret = 0;
2122	continue;
2123	} else if (ret) {
2124	return ret;
2125	}
2126	}
2127
2128	/*
2129	* Either success case or btrfs_run_delayed_refs_for_head
2130	* returned -EAGAIN, meaning we need to select another head
2131	*/
2132
2133	locked_ref = NULL;
2134	cond_resched();
2135	} while ((min_bytes != U64_MAX && bytes_processed < min_bytes) ||
2136	(max_count > 0 && count < max_count) ||
2137	locked_ref);
2138
2139	return 0;
2140	}
2141
2142	#ifdef SCRAMBLE_DELAYED_REFS
2143	/*
2144	* Normally delayed refs get processed in ascending bytenr order. This
2145	* correlates in most cases to the order added. To expose dependencies on this
2146	* order, we start to process the tree in the middle instead of the beginning
2147	*/
2148	static u64 find_middle(struct rb_root *root)
2149	{
2150	struct rb_node *n = root->rb_node;
2151	struct btrfs_delayed_ref_node *entry;
2152	int alt = 1;
2153	u64 middle;
2154	u64 first = 0, last = 0;
2155
2156	n = rb_first(root);
2157	if (n) {
2158	entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2159	first = entry->bytenr;
2160	}
2161	n = rb_last(root);
2162	if (n) {
2163	entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2164	last = entry->bytenr;
2165	}
2166	n = root->rb_node;
2167
2168	while (n) {
2169	entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2170	WARN_ON(!entry->in_tree);
2171
2172	middle = entry->bytenr;
2173
2174	if (alt)
2175	n = n->rb_left;
2176	else
2177	n = n->rb_right;
2178
2179	alt = 1 - alt;
2180	}
2181	return middle;
2182	}
2183	#endif
2184
2185	/*
2186	* Start processing the delayed reference count updates and extent insertions
2187	* we have queued up so far.
2188	*
2189	* @trans: Transaction handle.
2190	* @min_bytes: How many bytes of delayed references to process. After this
2191	* many bytes we stop processing delayed references if there are
2192	* any more. If 0 it means to run all existing delayed references,
2193	* but not new ones added after running all existing ones.
2194	* Use (u64)-1 (U64_MAX) to run all existing delayed references
2195	* plus any new ones that are added.
2196	*
2197	* Returns 0 on success or if called with an aborted transaction
2198	* Returns <0 on error and aborts the transaction
2199	*/
2200	int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, u64 min_bytes)
2201	{
2202	struct btrfs_fs_info *fs_info = trans->fs_info;
2203	struct btrfs_delayed_ref_root *delayed_refs;
2204	int ret;
2205
2206	/* We'll clean this up in btrfs_cleanup_transaction */
2207	if (TRANS_ABORTED(trans))
2208	return 0;
2209
2210	if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2211	return 0;
2212
2213	delayed_refs = &trans->transaction->delayed_refs;
2214	again:
2215	#ifdef SCRAMBLE_DELAYED_REFS
2216	delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2217	#endif
2218	ret = __btrfs_run_delayed_refs(trans, min_bytes);
2219	if (ret < 0) {
2220	btrfs_abort_transaction(trans, ret);
2221	return ret;
2222	}
2223
2224	if (min_bytes == U64_MAX) {
2225	btrfs_create_pending_block_groups(trans);
2226
2227	spin_lock(lock: &delayed_refs->lock);
2228	if (RB_EMPTY_ROOT(&delayed_refs->href_root.rb_root)) {
2229	spin_unlock(lock: &delayed_refs->lock);
2230	return 0;
2231	}
2232	spin_unlock(lock: &delayed_refs->lock);
2233
2234	cond_resched();
2235	goto again;
2236	}
2237
2238	return 0;
2239	}
2240
2241	int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2242	struct extent_buffer *eb, u64 flags)
2243	{
2244	struct btrfs_delayed_extent_op *extent_op;
2245	int level = btrfs_header_level(eb);
2246	int ret;
2247
2248	extent_op = btrfs_alloc_delayed_extent_op();
2249	if (!extent_op)
2250	return -ENOMEM;
2251
2252	extent_op->flags_to_set = flags;
2253	extent_op->update_flags = true;
2254	extent_op->update_key = false;
2255	extent_op->level = level;
2256
2257	ret = btrfs_add_delayed_extent_op(trans, bytenr: eb->start, num_bytes: eb->len, extent_op);
2258	if (ret)
2259	btrfs_free_delayed_extent_op(op: extent_op);
2260	return ret;
2261	}
2262
2263	static noinline int check_delayed_ref(struct btrfs_root *root,
2264	struct btrfs_path *path,
2265	u64 objectid, u64 offset, u64 bytenr)
2266	{
2267	struct btrfs_delayed_ref_head *head;
2268	struct btrfs_delayed_ref_node *ref;
2269	struct btrfs_delayed_data_ref *data_ref;
2270	struct btrfs_delayed_ref_root *delayed_refs;
2271	struct btrfs_transaction *cur_trans;
2272	struct rb_node *node;
2273	int ret = 0;
2274
2275	spin_lock(lock: &root->fs_info->trans_lock);
2276	cur_trans = root->fs_info->running_transaction;
2277	if (cur_trans)
2278	refcount_inc(r: &cur_trans->use_count);
2279	spin_unlock(lock: &root->fs_info->trans_lock);
2280	if (!cur_trans)
2281	return 0;
2282
2283	delayed_refs = &cur_trans->delayed_refs;
2284	spin_lock(lock: &delayed_refs->lock);
2285	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
2286	if (!head) {
2287	spin_unlock(lock: &delayed_refs->lock);
2288	btrfs_put_transaction(transaction: cur_trans);
2289	return 0;
2290	}
2291
2292	if (!mutex_trylock(lock: &head->mutex)) {
2293	if (path->nowait) {
2294	spin_unlock(lock: &delayed_refs->lock);
2295	btrfs_put_transaction(transaction: cur_trans);
2296	return -EAGAIN;
2297	}
2298
2299	refcount_inc(r: &head->refs);
2300	spin_unlock(lock: &delayed_refs->lock);
2301
2302	btrfs_release_path(p: path);
2303
2304	/*
2305	* Mutex was contended, block until it's released and let
2306	* caller try again
2307	*/
2308	mutex_lock(&head->mutex);
2309	mutex_unlock(lock: &head->mutex);
2310	btrfs_put_delayed_ref_head(head);
2311	btrfs_put_transaction(transaction: cur_trans);
2312	return -EAGAIN;
2313	}
2314	spin_unlock(lock: &delayed_refs->lock);
2315
2316	spin_lock(lock: &head->lock);
2317	/*
2318	* XXX: We should replace this with a proper search function in the
2319	* future.
2320	*/
2321	for (node = rb_first_cached(&head->ref_tree); node;
2322	node = rb_next(node)) {
2323	ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
2324	/* If it's a shared ref we know a cross reference exists */
2325	if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2326	ret = 1;
2327	break;
2328	}
2329
2330	data_ref = btrfs_delayed_node_to_data_ref(node: ref);
2331
2332	/*
2333	* If our ref doesn't match the one we're currently looking at
2334	* then we have a cross reference.
2335	*/
2336	if (data_ref->root != root->root_key.objectid ||
2337	data_ref->objectid != objectid ||
2338	data_ref->offset != offset) {
2339	ret = 1;
2340	break;
2341	}
2342	}
2343	spin_unlock(lock: &head->lock);
2344	mutex_unlock(lock: &head->mutex);
2345	btrfs_put_transaction(transaction: cur_trans);
2346	return ret;
2347	}
2348
2349	static noinline int check_committed_ref(struct btrfs_root *root,
2350	struct btrfs_path *path,
2351	u64 objectid, u64 offset, u64 bytenr,
2352	bool strict)
2353	{
2354	struct btrfs_fs_info *fs_info = root->fs_info;
2355	struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);
2356	struct extent_buffer *leaf;
2357	struct btrfs_extent_data_ref *ref;
2358	struct btrfs_extent_inline_ref *iref;
2359	struct btrfs_extent_item *ei;
2360	struct btrfs_key key;
2361	u32 item_size;
2362	u32 expected_size;
2363	int type;
2364	int ret;
2365
2366	key.objectid = bytenr;
2367	key.offset = (u64)-1;
2368	key.type = BTRFS_EXTENT_ITEM_KEY;
2369
2370	ret = btrfs_search_slot(NULL, root: extent_root, key: &key, p: path, ins_len: 0, cow: 0);
2371	if (ret < 0)
2372	goto out;
2373	BUG_ON(ret == 0); /* Corruption */
2374
2375	ret = -ENOENT;
2376	if (path->slots[0] == 0)
2377	goto out;
2378
2379	path->slots[0]--;
2380	leaf = path->nodes[0];
2381	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
2382
2383	if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2384	goto out;
2385
2386	ret = 1;
2387	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
2388	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2389	expected_size = sizeof(*ei) + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY);
2390
2391	/* No inline refs; we need to bail before checking for owner ref. */
2392	if (item_size == sizeof(*ei))
2393	goto out;
2394
2395	/* Check for an owner ref; skip over it to the real inline refs. */
2396	iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2397	type = btrfs_get_extent_inline_ref_type(eb: leaf, iref, is_data: BTRFS_REF_TYPE_DATA);
2398	if (btrfs_fs_incompat(fs_info, SIMPLE_QUOTA) && type == BTRFS_EXTENT_OWNER_REF_KEY) {
2399	expected_size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
2400	iref = (struct btrfs_extent_inline_ref *)(iref + 1);
2401	}
2402
2403	/* If extent item has more than 1 inline ref then it's shared */
2404	if (item_size != expected_size)
2405	goto out;
2406
2407	/*
2408	* If extent created before last snapshot => it's shared unless the
2409	* snapshot has been deleted. Use the heuristic if strict is false.
2410	*/
2411	if (!strict &&
2412	(btrfs_extent_generation(eb: leaf, s: ei) <=
2413	btrfs_root_last_snapshot(s: &root->root_item)))
2414	goto out;
2415
2416	/* If this extent has SHARED_DATA_REF then it's shared */
2417	type = btrfs_get_extent_inline_ref_type(eb: leaf, iref, is_data: BTRFS_REF_TYPE_DATA);
2418	if (type != BTRFS_EXTENT_DATA_REF_KEY)
2419	goto out;
2420
2421	ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2422	if (btrfs_extent_refs(eb: leaf, s: ei) !=
2423	btrfs_extent_data_ref_count(eb: leaf, s: ref) ||
2424	btrfs_extent_data_ref_root(eb: leaf, s: ref) !=
2425	root->root_key.objectid ||
2426	btrfs_extent_data_ref_objectid(eb: leaf, s: ref) != objectid ||
2427	btrfs_extent_data_ref_offset(eb: leaf, s: ref) != offset)
2428	goto out;
2429
2430	ret = 0;
2431	out:
2432	return ret;
2433	}
2434
2435	int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
2436	u64 bytenr, bool strict, struct btrfs_path *path)
2437	{
2438	int ret;
2439
2440	do {
2441	ret = check_committed_ref(root, path, objectid,
2442	offset, bytenr, strict);
2443	if (ret && ret != -ENOENT)
2444	goto out;
2445
2446	ret = check_delayed_ref(root, path, objectid, offset, bytenr);
2447	} while (ret == -EAGAIN);
2448
2449	out:
2450	btrfs_release_path(p: path);
2451	if (btrfs_is_data_reloc_root(root))
2452	WARN_ON(ret > 0);
2453	return ret;
2454	}
2455
2456	static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2457	struct btrfs_root *root,
2458	struct extent_buffer *buf,
2459	int full_backref, int inc)
2460	{
2461	struct btrfs_fs_info *fs_info = root->fs_info;
2462	u64 bytenr;
2463	u64 num_bytes;
2464	u64 parent;
2465	u64 ref_root;
2466	u32 nritems;
2467	struct btrfs_key key;
2468	struct btrfs_file_extent_item *fi;
2469	struct btrfs_ref generic_ref = { 0 };
2470	bool for_reloc = btrfs_header_flag(eb: buf, BTRFS_HEADER_FLAG_RELOC);
2471	int i;
2472	int action;
2473	int level;
2474	int ret = 0;
2475
2476	if (btrfs_is_testing(fs_info))
2477	return 0;
2478
2479	ref_root = btrfs_header_owner(eb: buf);
2480	nritems = btrfs_header_nritems(eb: buf);
2481	level = btrfs_header_level(eb: buf);
2482
2483	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)
2484	return 0;
2485
2486	if (full_backref)
2487	parent = buf->start;
2488	else
2489	parent = 0;
2490	if (inc)
2491	action = BTRFS_ADD_DELAYED_REF;
2492	else
2493	action = BTRFS_DROP_DELAYED_REF;
2494
2495	for (i = 0; i < nritems; i++) {
2496	if (level == 0) {
2497	btrfs_item_key_to_cpu(eb: buf, cpu_key: &key, nr: i);
2498	if (key.type != BTRFS_EXTENT_DATA_KEY)
2499	continue;
2500	fi = btrfs_item_ptr(buf, i,
2501	struct btrfs_file_extent_item);
2502	if (btrfs_file_extent_type(eb: buf, s: fi) ==
2503	BTRFS_FILE_EXTENT_INLINE)
2504	continue;
2505	bytenr = btrfs_file_extent_disk_bytenr(eb: buf, s: fi);
2506	if (bytenr == 0)
2507	continue;
2508
2509	num_bytes = btrfs_file_extent_disk_num_bytes(eb: buf, s: fi);
2510	key.offset -= btrfs_file_extent_offset(eb: buf, s: fi);
2511	btrfs_init_generic_ref(generic_ref: &generic_ref, action, bytenr,
2512	len: num_bytes, parent, owning_root: ref_root);
2513	btrfs_init_data_ref(generic_ref: &generic_ref, ref_root, ino: key.objectid,
2514	offset: key.offset, mod_root: root->root_key.objectid,
2515	skip_qgroup: for_reloc);
2516	if (inc)
2517	ret = btrfs_inc_extent_ref(trans, generic_ref: &generic_ref);
2518	else
2519	ret = btrfs_free_extent(trans, ref: &generic_ref);
2520	if (ret)
2521	goto fail;
2522	} else {
2523	bytenr = btrfs_node_blockptr(eb: buf, nr: i);
2524	num_bytes = fs_info->nodesize;
2525	/* We don't know the owning_root, use 0. */
2526	btrfs_init_generic_ref(generic_ref: &generic_ref, action, bytenr,
2527	len: num_bytes, parent, owning_root: 0);
2528	btrfs_init_tree_ref(generic_ref: &generic_ref, level: level - 1, root: ref_root,
2529	mod_root: root->root_key.objectid, skip_qgroup: for_reloc);
2530	if (inc)
2531	ret = btrfs_inc_extent_ref(trans, generic_ref: &generic_ref);
2532	else
2533	ret = btrfs_free_extent(trans, ref: &generic_ref);
2534	if (ret)
2535	goto fail;
2536	}
2537	}
2538	return 0;
2539	fail:
2540	return ret;
2541	}
2542
2543	int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2544	struct extent_buffer *buf, int full_backref)
2545	{
2546	return __btrfs_mod_ref(trans, root, buf, full_backref, inc: 1);
2547	}
2548
2549	int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2550	struct extent_buffer *buf, int full_backref)
2551	{
2552	return __btrfs_mod_ref(trans, root, buf, full_backref, inc: 0);
2553	}
2554
2555	static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
2556	{
2557	struct btrfs_fs_info *fs_info = root->fs_info;
2558	u64 flags;
2559	u64 ret;
2560
2561	if (data)
2562	flags = BTRFS_BLOCK_GROUP_DATA;
2563	else if (root == fs_info->chunk_root)
2564	flags = BTRFS_BLOCK_GROUP_SYSTEM;
2565	else
2566	flags = BTRFS_BLOCK_GROUP_METADATA;
2567
2568	ret = btrfs_get_alloc_profile(fs_info, orig_flags: flags);
2569	return ret;
2570	}
2571
2572	static u64 first_logical_byte(struct btrfs_fs_info *fs_info)
2573	{
2574	struct rb_node *leftmost;
2575	u64 bytenr = 0;
2576
2577	read_lock(&fs_info->block_group_cache_lock);
2578	/* Get the block group with the lowest logical start address. */
2579	leftmost = rb_first_cached(&fs_info->block_group_cache_tree);
2580	if (leftmost) {
2581	struct btrfs_block_group *bg;
2582
2583	bg = rb_entry(leftmost, struct btrfs_block_group, cache_node);
2584	bytenr = bg->start;
2585	}
2586	read_unlock(&fs_info->block_group_cache_lock);
2587
2588	return bytenr;
2589	}
2590
2591	static int pin_down_extent(struct btrfs_trans_handle *trans,
2592	struct btrfs_block_group *cache,
2593	u64 bytenr, u64 num_bytes, int reserved)
2594	{
2595	struct btrfs_fs_info *fs_info = cache->fs_info;
2596
2597	spin_lock(lock: &cache->space_info->lock);
2598	spin_lock(lock: &cache->lock);
2599	cache->pinned += num_bytes;
2600	btrfs_space_info_update_bytes_pinned(fs_info, sinfo: cache->space_info,
2601	bytes: num_bytes);
2602	if (reserved) {
2603	cache->reserved -= num_bytes;
2604	cache->space_info->bytes_reserved -= num_bytes;
2605	}
2606	spin_unlock(lock: &cache->lock);
2607	spin_unlock(lock: &cache->space_info->lock);
2608
2609	set_extent_bit(tree: &trans->transaction->pinned_extents, start: bytenr,
2610	end: bytenr + num_bytes - 1, bits: EXTENT_DIRTY, NULL);
2611	return 0;
2612	}
2613
2614	int btrfs_pin_extent(struct btrfs_trans_handle *trans,
2615	u64 bytenr, u64 num_bytes, int reserved)
2616	{
2617	struct btrfs_block_group *cache;
2618
2619	cache = btrfs_lookup_block_group(info: trans->fs_info, bytenr);
2620	BUG_ON(!cache); /* Logic error */
2621
2622	pin_down_extent(trans, cache, bytenr, num_bytes, reserved);
2623
2624	btrfs_put_block_group(cache);
2625	return 0;
2626	}
2627
2628	int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
2629	const struct extent_buffer *eb)
2630	{
2631	struct btrfs_block_group *cache;
2632	int ret;
2633
2634	cache = btrfs_lookup_block_group(info: trans->fs_info, bytenr: eb->start);
2635	if (!cache)
2636	return -EINVAL;
2637
2638	/*
2639	* Fully cache the free space first so that our pin removes the free space
2640	* from the cache.
2641	*/
2642	ret = btrfs_cache_block_group(cache, wait: true);
2643	if (ret)
2644	goto out;
2645
2646	pin_down_extent(trans, cache, bytenr: eb->start, num_bytes: eb->len, reserved: 0);
2647
2648	/* remove us from the free space cache (if we're there at all) */
2649	ret = btrfs_remove_free_space(block_group: cache, bytenr: eb->start, size: eb->len);
2650	out:
2651	btrfs_put_block_group(cache);
2652	return ret;
2653	}
2654
2655	static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
2656	u64 start, u64 num_bytes)
2657	{
2658	int ret;
2659	struct btrfs_block_group *block_group;
2660
2661	block_group = btrfs_lookup_block_group(info: fs_info, bytenr: start);
2662	if (!block_group)
2663	return -EINVAL;
2664
2665	ret = btrfs_cache_block_group(cache: block_group, wait: true);
2666	if (ret)
2667	goto out;
2668
2669	ret = btrfs_remove_free_space(block_group, bytenr: start, size: num_bytes);
2670	out:
2671	btrfs_put_block_group(cache: block_group);
2672	return ret;
2673	}
2674
2675	int btrfs_exclude_logged_extents(struct extent_buffer *eb)
2676	{
2677	struct btrfs_fs_info *fs_info = eb->fs_info;
2678	struct btrfs_file_extent_item *item;
2679	struct btrfs_key key;
2680	int found_type;
2681	int i;
2682	int ret = 0;
2683
2684	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
2685	return 0;
2686
2687	for (i = 0; i < btrfs_header_nritems(eb); i++) {
2688	btrfs_item_key_to_cpu(eb, cpu_key: &key, nr: i);
2689	if (key.type != BTRFS_EXTENT_DATA_KEY)
2690	continue;
2691	item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
2692	found_type = btrfs_file_extent_type(eb, s: item);
2693	if (found_type == BTRFS_FILE_EXTENT_INLINE)
2694	continue;
2695	if (btrfs_file_extent_disk_bytenr(eb, s: item) == 0)
2696	continue;
2697	key.objectid = btrfs_file_extent_disk_bytenr(eb, s: item);
2698	key.offset = btrfs_file_extent_disk_num_bytes(eb, s: item);
2699	ret = __exclude_logged_extent(fs_info, start: key.objectid, num_bytes: key.offset);
2700	if (ret)
2701	break;
2702	}
2703
2704	return ret;
2705	}
2706
2707	static void
2708	btrfs_inc_block_group_reservations(struct btrfs_block_group *bg)
2709	{
2710	atomic_inc(v: &bg->reservations);
2711	}
2712
2713	/*
2714	* Returns the free cluster for the given space info and sets empty_cluster to
2715	* what it should be based on the mount options.
2716	*/
2717	static struct btrfs_free_cluster *
2718	fetch_cluster_info(struct btrfs_fs_info *fs_info,
2719	struct btrfs_space_info *space_info, u64 *empty_cluster)
2720	{
2721	struct btrfs_free_cluster *ret = NULL;
2722
2723	*empty_cluster = 0;
2724	if (btrfs_mixed_space_info(space_info))
2725	return ret;
2726
2727	if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
2728	ret = &fs_info->meta_alloc_cluster;
2729	if (btrfs_test_opt(fs_info, SSD))
2730	*empty_cluster = SZ_2M;
2731	else
2732	*empty_cluster = SZ_64K;
2733	} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
2734	btrfs_test_opt(fs_info, SSD_SPREAD)) {
2735	*empty_cluster = SZ_2M;
2736	ret = &fs_info->data_alloc_cluster;
2737	}
2738
2739	return ret;
2740	}
2741
2742	static int unpin_extent_range(struct btrfs_fs_info *fs_info,
2743	u64 start, u64 end,
2744	const bool return_free_space)
2745	{
2746	struct btrfs_block_group *cache = NULL;
2747	struct btrfs_space_info *space_info;
2748	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
2749	struct btrfs_free_cluster *cluster = NULL;
2750	u64 len;
2751	u64 total_unpinned = 0;
2752	u64 empty_cluster = 0;
2753	bool readonly;
2754
2755	while (start <= end) {
2756	readonly = false;
2757	if (!cache ||
2758	start >= cache->start + cache->length) {
2759	if (cache)
2760	btrfs_put_block_group(cache);
2761	total_unpinned = 0;
2762	cache = btrfs_lookup_block_group(info: fs_info, bytenr: start);
2763	BUG_ON(!cache); /* Logic error */
2764
2765	cluster = fetch_cluster_info(fs_info,
2766	space_info: cache->space_info,
2767	empty_cluster: &empty_cluster);
2768	empty_cluster <<= 1;
2769	}
2770
2771	len = cache->start + cache->length - start;
2772	len = min(len, end + 1 - start);
2773
2774	if (return_free_space)
2775	btrfs_add_free_space(block_group: cache, bytenr: start, size: len);
2776
2777	start += len;
2778	total_unpinned += len;
2779	space_info = cache->space_info;
2780
2781	/*
2782	* If this space cluster has been marked as fragmented and we've
2783	* unpinned enough in this block group to potentially allow a
2784	* cluster to be created inside of it go ahead and clear the
2785	* fragmented check.
2786	*/
2787	if (cluster && cluster->fragmented &&
2788	total_unpinned > empty_cluster) {
2789	spin_lock(lock: &cluster->lock);
2790	cluster->fragmented = 0;
2791	spin_unlock(lock: &cluster->lock);
2792	}
2793
2794	spin_lock(lock: &space_info->lock);
2795	spin_lock(lock: &cache->lock);
2796	cache->pinned -= len;
2797	btrfs_space_info_update_bytes_pinned(fs_info, sinfo: space_info, bytes: -len);
2798	space_info->max_extent_size = 0;
2799	if (cache->ro) {
2800	space_info->bytes_readonly += len;
2801	readonly = true;
2802	} else if (btrfs_is_zoned(fs_info)) {
2803	/* Need reset before reusing in a zoned block group */
2804	space_info->bytes_zone_unusable += len;
2805	readonly = true;
2806	}
2807	spin_unlock(lock: &cache->lock);
2808	if (!readonly && return_free_space &&
2809	global_rsv->space_info == space_info) {
2810	spin_lock(lock: &global_rsv->lock);
2811	if (!global_rsv->full) {
2812	u64 to_add = min(len, global_rsv->size -
2813	global_rsv->reserved);
2814
2815	global_rsv->reserved += to_add;
2816	btrfs_space_info_update_bytes_may_use(fs_info,
2817	sinfo: space_info, bytes: to_add);
2818	if (global_rsv->reserved >= global_rsv->size)
2819	global_rsv->full = 1;
2820	len -= to_add;
2821	}
2822	spin_unlock(lock: &global_rsv->lock);
2823	}
2824	/* Add to any tickets we may have */
2825	if (!readonly && return_free_space && len)
2826	btrfs_try_granting_tickets(fs_info, space_info);
2827	spin_unlock(lock: &space_info->lock);
2828	}
2829
2830	if (cache)
2831	btrfs_put_block_group(cache);
2832	return 0;
2833	}
2834
2835	int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
2836	{
2837	struct btrfs_fs_info *fs_info = trans->fs_info;
2838	struct btrfs_block_group *block_group, *tmp;
2839	struct list_head *deleted_bgs;
2840	struct extent_io_tree *unpin;
2841	u64 start;
2842	u64 end;
2843	int ret;
2844
2845	unpin = &trans->transaction->pinned_extents;
2846
2847	while (!TRANS_ABORTED(trans)) {
2848	struct extent_state *cached_state = NULL;
2849
2850	mutex_lock(&fs_info->unused_bg_unpin_mutex);
2851	if (!find_first_extent_bit(tree: unpin, start: 0, start_ret: &start, end_ret: &end,
2852	bits: EXTENT_DIRTY, cached_state: &cached_state)) {
2853	mutex_unlock(lock: &fs_info->unused_bg_unpin_mutex);
2854	break;
2855	}
2856
2857	if (btrfs_test_opt(fs_info, DISCARD_SYNC))
2858	ret = btrfs_discard_extent(fs_info, bytenr: start,
2859	num_bytes: end + 1 - start, NULL);
2860
2861	clear_extent_dirty(tree: unpin, start, end, cached: &cached_state);
2862	unpin_extent_range(fs_info, start, end, return_free_space: true);
2863	mutex_unlock(lock: &fs_info->unused_bg_unpin_mutex);
2864	free_extent_state(state: cached_state);
2865	cond_resched();
2866	}
2867
2868	if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
2869	btrfs_discard_calc_delay(discard_ctl: &fs_info->discard_ctl);
2870	btrfs_discard_schedule_work(discard_ctl: &fs_info->discard_ctl, override: true);
2871	}
2872
2873	/*
2874	* Transaction is finished. We don't need the lock anymore. We
2875	* do need to clean up the block groups in case of a transaction
2876	* abort.
2877	*/
2878	deleted_bgs = &trans->transaction->deleted_bgs;
2879	list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
2880	u64 trimmed = 0;
2881
2882	ret = -EROFS;
2883	if (!TRANS_ABORTED(trans))
2884	ret = btrfs_discard_extent(fs_info,
2885	bytenr: block_group->start,
2886	num_bytes: block_group->length,
2887	actual_bytes: &trimmed);
2888
2889	list_del_init(entry: &block_group->bg_list);
2890	btrfs_unfreeze_block_group(cache: block_group);
2891	btrfs_put_block_group(cache: block_group);
2892
2893	if (ret) {
2894	const char *errstr = btrfs_decode_error(error: ret);
2895	btrfs_warn(fs_info,
2896	"discard failed while removing blockgroup: errno=%d %s",
2897	ret, errstr);
2898	}
2899	}
2900
2901	return 0;
2902	}
2903
2904	/*
2905	* Parse an extent item's inline extents looking for a simple quotas owner ref.
2906	*
2907	* @fs_info: the btrfs_fs_info for this mount
2908	* @leaf: a leaf in the extent tree containing the extent item
2909	* @slot: the slot in the leaf where the extent item is found
2910	*
2911	* Returns the objectid of the root that originally allocated the extent item
2912	* if the inline owner ref is expected and present, otherwise 0.
2913	*
2914	* If an extent item has an owner ref item, it will be the first inline ref
2915	* item. Therefore the logic is to check whether there are any inline ref
2916	* items, then check the type of the first one.
2917	*/
2918	u64 btrfs_get_extent_owner_root(struct btrfs_fs_info *fs_info,
2919	struct extent_buffer *leaf, int slot)
2920	{
2921	struct btrfs_extent_item *ei;
2922	struct btrfs_extent_inline_ref *iref;
2923	struct btrfs_extent_owner_ref *oref;
2924	unsigned long ptr;
2925	unsigned long end;
2926	int type;
2927
2928	if (!btrfs_fs_incompat(fs_info, SIMPLE_QUOTA))
2929	return 0;
2930
2931	ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
2932	ptr = (unsigned long)(ei + 1);
2933	end = (unsigned long)ei + btrfs_item_size(eb: leaf, slot);
2934
2935	/* No inline ref items of any kind, can't check type. */
2936	if (ptr == end)
2937	return 0;
2938
2939	iref = (struct btrfs_extent_inline_ref *)ptr;
2940	type = btrfs_get_extent_inline_ref_type(eb: leaf, iref, is_data: BTRFS_REF_TYPE_ANY);
2941
2942	/* We found an owner ref, get the root out of it. */
2943	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
2944	oref = (struct btrfs_extent_owner_ref *)(&iref->offset);
2945	return btrfs_extent_owner_ref_root_id(eb: leaf, s: oref);
2946	}
2947
2948	/* We have inline refs, but not an owner ref. */
2949	return 0;
2950	}
2951
2952	static int do_free_extent_accounting(struct btrfs_trans_handle *trans,
2953	u64 bytenr, struct btrfs_squota_delta *delta)
2954	{
2955	int ret;
2956	u64 num_bytes = delta->num_bytes;
2957
2958	if (delta->is_data) {
2959	struct btrfs_root *csum_root;
2960
2961	csum_root = btrfs_csum_root(fs_info: trans->fs_info, bytenr);
2962	ret = btrfs_del_csums(trans, root: csum_root, bytenr, len: num_bytes);
2963	if (ret) {
2964	btrfs_abort_transaction(trans, ret);
2965	return ret;
2966	}
2967
2968	ret = btrfs_delete_raid_extent(trans, start: bytenr, length: num_bytes);
2969	if (ret) {
2970	btrfs_abort_transaction(trans, ret);
2971	return ret;
2972	}
2973	}
2974
2975	ret = btrfs_record_squota_delta(fs_info: trans->fs_info, delta);
2976	if (ret) {
2977	btrfs_abort_transaction(trans, ret);
2978	return ret;
2979	}
2980
2981	ret = add_to_free_space_tree(trans, start: bytenr, size: num_bytes);
2982	if (ret) {
2983	btrfs_abort_transaction(trans, ret);
2984	return ret;
2985	}
2986
2987	ret = btrfs_update_block_group(trans, bytenr, num_bytes, alloc: false);
2988	if (ret)
2989	btrfs_abort_transaction(trans, ret);
2990
2991	return ret;
2992	}
2993
2994	#define abort_and_dump(trans, path, fmt, args...) \
2995	({ \
2996	btrfs_abort_transaction(trans, -EUCLEAN); \
2997	btrfs_print_leaf(path->nodes[0]); \
2998	btrfs_crit(trans->fs_info, fmt, ##args); \
2999	})
3000
3001	/*
3002	* Drop one or more refs of @node.
3003	*
3004	* 1. Locate the extent refs.
3005	* It's either inline in EXTENT/METADATA_ITEM or in keyed SHARED_* item.
3006	* Locate it, then reduce the refs number or remove the ref line completely.
3007	*
3008	* 2. Update the refs count in EXTENT/METADATA_ITEM
3009	*
3010	* Inline backref case:
3011	*
3012	* in extent tree we have:
3013	*
3014	* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
3015	* refs 2 gen 6 flags DATA
3016	* extent data backref root FS_TREE objectid 258 offset 0 count 1
3017	* extent data backref root FS_TREE objectid 257 offset 0 count 1
3018	*
3019	* This function gets called with:
3020	*
3021	* node->bytenr = 13631488
3022	* node->num_bytes = 1048576
3023	* root_objectid = FS_TREE
3024	* owner_objectid = 257
3025	* owner_offset = 0
3026	* refs_to_drop = 1
3027	*
3028	* Then we should get some like:
3029	*
3030	* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
3031	* refs 1 gen 6 flags DATA
3032	* extent data backref root FS_TREE objectid 258 offset 0 count 1
3033	*
3034	* Keyed backref case:
3035	*
3036	* in extent tree we have:
3037	*
3038	* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
3039	* refs 754 gen 6 flags DATA
3040	* [...]
3041	* item 2 key (13631488 EXTENT_DATA_REF <HASH>) itemoff 3915 itemsize 28
3042	* extent data backref root FS_TREE objectid 866 offset 0 count 1
3043	*
3044	* This function get called with:
3045	*
3046	* node->bytenr = 13631488
3047	* node->num_bytes = 1048576
3048	* root_objectid = FS_TREE
3049	* owner_objectid = 866
3050	* owner_offset = 0
3051	* refs_to_drop = 1
3052	*
3053	* Then we should get some like:
3054	*
3055	* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
3056	* refs 753 gen 6 flags DATA
3057	*
3058	* And that (13631488 EXTENT_DATA_REF <HASH>) gets removed.
3059	*/
3060	static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
3061	struct btrfs_delayed_ref_head *href,
3062	struct btrfs_delayed_ref_node *node, u64 parent,
3063	u64 root_objectid, u64 owner_objectid,
3064	u64 owner_offset,
3065	struct btrfs_delayed_extent_op *extent_op)
3066	{
3067	struct btrfs_fs_info *info = trans->fs_info;
3068	struct btrfs_key key;
3069	struct btrfs_path *path;
3070	struct btrfs_root *extent_root;
3071	struct extent_buffer *leaf;
3072	struct btrfs_extent_item *ei;
3073	struct btrfs_extent_inline_ref *iref;
3074	int ret;
3075	int is_data;
3076	int extent_slot = 0;
3077	int found_extent = 0;
3078	int num_to_del = 1;
3079	int refs_to_drop = node->ref_mod;
3080	u32 item_size;
3081	u64 refs;
3082	u64 bytenr = node->bytenr;
3083	u64 num_bytes = node->num_bytes;
3084	bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
3085	u64 delayed_ref_root = href->owning_root;
3086
3087	extent_root = btrfs_extent_root(fs_info: info, bytenr);
3088	ASSERT(extent_root);
3089
3090	path = btrfs_alloc_path();
3091	if (!path)
3092	return -ENOMEM;
3093
3094	is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
3095
3096	if (!is_data && refs_to_drop != 1) {
3097	btrfs_crit(info,
3098	"invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u",
3099	node->bytenr, refs_to_drop);
3100	ret = -EINVAL;
3101	btrfs_abort_transaction(trans, ret);
3102	goto out;
3103	}
3104
3105	if (is_data)
3106	skinny_metadata = false;
3107
3108	ret = lookup_extent_backref(trans, path, ref_ret: &iref, bytenr, num_bytes,
3109	parent, root_objectid, owner: owner_objectid,
3110	offset: owner_offset);
3111	if (ret == 0) {
3112	/*
3113	* Either the inline backref or the SHARED_DATA_REF/
3114	* SHARED_BLOCK_REF is found
3115	*
3116	* Here is a quick path to locate EXTENT/METADATA_ITEM.
3117	* It's possible the EXTENT/METADATA_ITEM is near current slot.
3118	*/
3119	extent_slot = path->slots[0];
3120	while (extent_slot >= 0) {
3121	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key,
3122	nr: extent_slot);
3123	if (key.objectid != bytenr)
3124	break;
3125	if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3126	key.offset == num_bytes) {
3127	found_extent = 1;
3128	break;
3129	}
3130	if (key.type == BTRFS_METADATA_ITEM_KEY &&
3131	key.offset == owner_objectid) {
3132	found_extent = 1;
3133	break;
3134	}
3135
3136	/* Quick path didn't find the EXTEMT/METADATA_ITEM */
3137	if (path->slots[0] - extent_slot > 5)
3138	break;
3139	extent_slot--;
3140	}
3141
3142	if (!found_extent) {
3143	if (iref) {
3144	abort_and_dump(trans, path,
3145	"invalid iref slot %u, no EXTENT/METADATA_ITEM found but has inline extent ref",
3146	path->slots[0]);
3147	ret = -EUCLEAN;
3148	goto out;
3149	}
3150	/* Must be SHARED_* item, remove the backref first */
3151	ret = remove_extent_backref(trans, root: extent_root, path,
3152	NULL, refs_to_drop, is_data);
3153	if (ret) {
3154	btrfs_abort_transaction(trans, ret);
3155	goto out;
3156	}
3157	btrfs_release_path(p: path);
3158
3159	/* Slow path to locate EXTENT/METADATA_ITEM */
3160	key.objectid = bytenr;
3161	key.type = BTRFS_EXTENT_ITEM_KEY;
3162	key.offset = num_bytes;
3163
3164	if (!is_data && skinny_metadata) {
3165	key.type = BTRFS_METADATA_ITEM_KEY;
3166	key.offset = owner_objectid;
3167	}
3168
3169	ret = btrfs_search_slot(trans, root: extent_root,
3170	key: &key, p: path, ins_len: -1, cow: 1);
3171	if (ret > 0 && skinny_metadata && path->slots[0]) {
3172	/*
3173	* Couldn't find our skinny metadata item,
3174	* see if we have ye olde extent item.
3175	*/
3176	path->slots[0]--;
3177	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key,
3178	nr: path->slots[0]);
3179	if (key.objectid == bytenr &&
3180	key.type == BTRFS_EXTENT_ITEM_KEY &&
3181	key.offset == num_bytes)
3182	ret = 0;
3183	}
3184
3185	if (ret > 0 && skinny_metadata) {
3186	skinny_metadata = false;
3187	key.objectid = bytenr;
3188	key.type = BTRFS_EXTENT_ITEM_KEY;
3189	key.offset = num_bytes;
3190	btrfs_release_path(p: path);
3191	ret = btrfs_search_slot(trans, root: extent_root,
3192	key: &key, p: path, ins_len: -1, cow: 1);
3193	}
3194
3195	if (ret) {
3196	if (ret > 0)
3197	btrfs_print_leaf(l: path->nodes[0]);
3198	btrfs_err(info,
3199	"umm, got %d back from search, was looking for %llu, slot %d",
3200	ret, bytenr, path->slots[0]);
3201	}
3202	if (ret < 0) {
3203	btrfs_abort_transaction(trans, ret);
3204	goto out;
3205	}
3206	extent_slot = path->slots[0];
3207	}
3208	} else if (WARN_ON(ret == -ENOENT)) {
3209	abort_and_dump(trans, path,
3210	"unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu slot %d",
3211	bytenr, parent, root_objectid, owner_objectid,
3212	owner_offset, path->slots[0]);
3213	goto out;
3214	} else {
3215	btrfs_abort_transaction(trans, ret);
3216	goto out;
3217	}
3218
3219	leaf = path->nodes[0];
3220	item_size = btrfs_item_size(eb: leaf, slot: extent_slot);
3221	if (unlikely(item_size < sizeof(*ei))) {
3222	ret = -EUCLEAN;
3223	btrfs_err(trans->fs_info,
3224	"unexpected extent item size, has %u expect >= %zu",
3225	item_size, sizeof(*ei));
3226	btrfs_abort_transaction(trans, ret);
3227	goto out;
3228	}
3229	ei = btrfs_item_ptr(leaf, extent_slot,
3230	struct btrfs_extent_item);
3231	if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
3232	key.type == BTRFS_EXTENT_ITEM_KEY) {
3233	struct btrfs_tree_block_info *bi;
3234
3235	if (item_size < sizeof(*ei) + sizeof(*bi)) {
3236	abort_and_dump(trans, path,
3237	"invalid extent item size for key (%llu, %u, %llu) slot %u owner %llu, has %u expect >= %zu",
3238	key.objectid, key.type, key.offset,
3239	path->slots[0], owner_objectid, item_size,
3240	sizeof(*ei) + sizeof(*bi));
3241	ret = -EUCLEAN;
3242	goto out;
3243	}
3244	bi = (struct btrfs_tree_block_info *)(ei + 1);
3245	WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
3246	}
3247
3248	refs = btrfs_extent_refs(eb: leaf, s: ei);
3249	if (refs < refs_to_drop) {
3250	abort_and_dump(trans, path,
3251	"trying to drop %d refs but we only have %llu for bytenr %llu slot %u",
3252	refs_to_drop, refs, bytenr, path->slots[0]);
3253	ret = -EUCLEAN;
3254	goto out;
3255	}
3256	refs -= refs_to_drop;
3257
3258	if (refs > 0) {
3259	if (extent_op)
3260	__run_delayed_extent_op(extent_op, leaf, ei);
3261	/*
3262	* In the case of inline back ref, reference count will
3263	* be updated by remove_extent_backref
3264	*/
3265	if (iref) {
3266	if (!found_extent) {
3267	abort_and_dump(trans, path,
3268	"invalid iref, got inlined extent ref but no EXTENT/METADATA_ITEM found, slot %u",
3269	path->slots[0]);
3270	ret = -EUCLEAN;
3271	goto out;
3272	}
3273	} else {
3274	btrfs_set_extent_refs(eb: leaf, s: ei, val: refs);
3275	btrfs_mark_buffer_dirty(trans, buf: leaf);
3276	}
3277	if (found_extent) {
3278	ret = remove_extent_backref(trans, root: extent_root, path,
3279	iref, refs_to_drop, is_data);
3280	if (ret) {
3281	btrfs_abort_transaction(trans, ret);
3282	goto out;
3283	}
3284	}
3285	} else {
3286	struct btrfs_squota_delta delta = {
3287	.root = delayed_ref_root,
3288	.num_bytes = num_bytes,
3289	.rsv_bytes = 0,
3290	.is_data = is_data,
3291	.is_inc = false,
3292	.generation = btrfs_extent_generation(eb: leaf, s: ei),
3293	};
3294
3295	/* In this branch refs == 1 */
3296	if (found_extent) {
3297	if (is_data && refs_to_drop !=
3298	extent_data_ref_count(path, iref)) {
3299	abort_and_dump(trans, path,
3300	"invalid refs_to_drop, current refs %u refs_to_drop %u slot %u",
3301	extent_data_ref_count(path, iref),
3302	refs_to_drop, path->slots[0]);
3303	ret = -EUCLEAN;
3304	goto out;
3305	}
3306	if (iref) {
3307	if (path->slots[0] != extent_slot) {
3308	abort_and_dump(trans, path,
3309	"invalid iref, extent item key (%llu %u %llu) slot %u doesn't have wanted iref",
3310	key.objectid, key.type,
3311	key.offset, path->slots[0]);
3312	ret = -EUCLEAN;
3313	goto out;
3314	}
3315	} else {
3316	/*
3317	* No inline ref, we must be at SHARED_* item,
3318	* And it's single ref, it must be:
3319	* | extent_slot ||extent_slot + 1|
3320	* [ EXTENT/METADATA_ITEM ][ SHARED_* ITEM ]
3321	*/
3322	if (path->slots[0] != extent_slot + 1) {
3323	abort_and_dump(trans, path,
3324	"invalid SHARED_* item slot %u, previous item is not EXTENT/METADATA_ITEM",
3325	path->slots[0]);
3326	ret = -EUCLEAN;
3327	goto out;
3328	}
3329	path->slots[0] = extent_slot;
3330	num_to_del = 2;
3331	}
3332	}
3333	/*
3334	* We can't infer the data owner from the delayed ref, so we need
3335	* to try to get it from the owning ref item.
3336	*
3337	* If it is not present, then that extent was not written under
3338	* simple quotas mode, so we don't need to account for its deletion.
3339	*/
3340	if (is_data)
3341	delta.root = btrfs_get_extent_owner_root(fs_info: trans->fs_info,
3342	leaf, slot: extent_slot);
3343
3344	ret = btrfs_del_items(trans, root: extent_root, path, slot: path->slots[0],
3345	nr: num_to_del);
3346	if (ret) {
3347	btrfs_abort_transaction(trans, ret);
3348	goto out;
3349	}
3350	btrfs_release_path(p: path);
3351
3352	ret = do_free_extent_accounting(trans, bytenr, delta: &delta);
3353	}
3354	btrfs_release_path(p: path);
3355
3356	out:
3357	btrfs_free_path(p: path);
3358	return ret;
3359	}
3360
3361	/*
3362	* when we free an block, it is possible (and likely) that we free the last
3363	* delayed ref for that extent as well. This searches the delayed ref tree for
3364	* a given extent, and if there are no other delayed refs to be processed, it
3365	* removes it from the tree.
3366	*/
3367	static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
3368	u64 bytenr)
3369	{
3370	struct btrfs_delayed_ref_head *head;
3371	struct btrfs_delayed_ref_root *delayed_refs;
3372	int ret = 0;
3373
3374	delayed_refs = &trans->transaction->delayed_refs;
3375	spin_lock(lock: &delayed_refs->lock);
3376	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3377	if (!head)
3378	goto out_delayed_unlock;
3379
3380	spin_lock(lock: &head->lock);
3381	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
3382	goto out;
3383
3384	if (cleanup_extent_op(head) != NULL)
3385	goto out;
3386
3387	/*
3388	* waiting for the lock here would deadlock. If someone else has it
3389	* locked they are already in the process of dropping it anyway
3390	*/
3391	if (!mutex_trylock(lock: &head->mutex))
3392	goto out;
3393
3394	btrfs_delete_ref_head(delayed_refs, head);
3395	head->processing = false;
3396
3397	spin_unlock(lock: &head->lock);
3398	spin_unlock(lock: &delayed_refs->lock);
3399
3400	BUG_ON(head->extent_op);
3401	if (head->must_insert_reserved)
3402	ret = 1;
3403
3404	btrfs_cleanup_ref_head_accounting(fs_info: trans->fs_info, delayed_refs, head);
3405	mutex_unlock(lock: &head->mutex);
3406	btrfs_put_delayed_ref_head(head);
3407	return ret;
3408	out:
3409	spin_unlock(lock: &head->lock);
3410
3411	out_delayed_unlock:
3412	spin_unlock(lock: &delayed_refs->lock);
3413	return 0;
3414	}
3415
3416	void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
3417	u64 root_id,
3418	struct extent_buffer *buf,
3419	u64 parent, int last_ref)
3420	{
3421	struct btrfs_fs_info *fs_info = trans->fs_info;
3422	struct btrfs_ref generic_ref = { 0 };
3423	int ret;
3424
3425	btrfs_init_generic_ref(generic_ref: &generic_ref, action: BTRFS_DROP_DELAYED_REF,
3426	bytenr: buf->start, len: buf->len, parent, owning_root: btrfs_header_owner(eb: buf));
3427	btrfs_init_tree_ref(generic_ref: &generic_ref, level: btrfs_header_level(eb: buf),
3428	root: root_id, mod_root: 0, skip_qgroup: false);
3429
3430	if (root_id != BTRFS_TREE_LOG_OBJECTID) {
3431	btrfs_ref_tree_mod(fs_info, generic_ref: &generic_ref);
3432	ret = btrfs_add_delayed_tree_ref(trans, generic_ref: &generic_ref, NULL);
3433	BUG_ON(ret); /* -ENOMEM */
3434	}
3435
3436	if (last_ref && btrfs_header_generation(eb: buf) == trans->transid) {
3437	struct btrfs_block_group *cache;
3438	bool must_pin = false;
3439
3440	if (root_id != BTRFS_TREE_LOG_OBJECTID) {
3441	ret = check_ref_cleanup(trans, bytenr: buf->start);
3442	if (!ret) {
3443	btrfs_redirty_list_add(trans: trans->transaction, eb: buf);
3444	goto out;
3445	}
3446	}
3447
3448	cache = btrfs_lookup_block_group(info: fs_info, bytenr: buf->start);
3449
3450	if (btrfs_header_flag(eb: buf, BTRFS_HEADER_FLAG_WRITTEN)) {
3451	pin_down_extent(trans, cache, bytenr: buf->start, num_bytes: buf->len, reserved: 1);
3452	btrfs_put_block_group(cache);
3453	goto out;
3454	}
3455
3456	/*
3457	* If there are tree mod log users we may have recorded mod log
3458	* operations for this node. If we re-allocate this node we
3459	* could replay operations on this node that happened when it
3460	* existed in a completely different root. For example if it
3461	* was part of root A, then was reallocated to root B, and we
3462	* are doing a btrfs_old_search_slot(root b), we could replay
3463	* operations that happened when the block was part of root A,
3464	* giving us an inconsistent view of the btree.
3465	*
3466	* We are safe from races here because at this point no other
3467	* node or root points to this extent buffer, so if after this
3468	* check a new tree mod log user joins we will not have an
3469	* existing log of operations on this node that we have to
3470	* contend with.
3471	*/
3472	if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
3473	must_pin = true;
3474
3475	if (must_pin || btrfs_is_zoned(fs_info)) {
3476	btrfs_redirty_list_add(trans: trans->transaction, eb: buf);
3477	pin_down_extent(trans, cache, bytenr: buf->start, num_bytes: buf->len, reserved: 1);
3478	btrfs_put_block_group(cache);
3479	goto out;
3480	}
3481
3482	WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
3483
3484	btrfs_add_free_space(block_group: cache, bytenr: buf->start, size: buf->len);
3485	btrfs_free_reserved_bytes(cache, num_bytes: buf->len, delalloc: 0);
3486	btrfs_put_block_group(cache);
3487	trace_btrfs_reserved_extent_free(fs_info, start: buf->start, len: buf->len);
3488	}
3489	out:
3490	if (last_ref) {
3491	/*
3492	* Deleting the buffer, clear the corrupt flag since it doesn't
3493	* matter anymore.
3494	*/
3495	clear_bit(nr: EXTENT_BUFFER_CORRUPT, addr: &buf->bflags);
3496	}
3497	}
3498
3499	/* Can return -ENOMEM */
3500	int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
3501	{
3502	struct btrfs_fs_info *fs_info = trans->fs_info;
3503	int ret;
3504
3505	if (btrfs_is_testing(fs_info))
3506	return 0;
3507
3508	/*
3509	* tree log blocks never actually go into the extent allocation
3510	* tree, just update pinning info and exit early.
3511	*/
3512	if ((ref->type == BTRFS_REF_METADATA &&
3513	ref->tree_ref.ref_root == BTRFS_TREE_LOG_OBJECTID) ||
3514	(ref->type == BTRFS_REF_DATA &&
3515	ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
3516	btrfs_pin_extent(trans, bytenr: ref->bytenr, num_bytes: ref->len, reserved: 1);
3517	ret = 0;
3518	} else if (ref->type == BTRFS_REF_METADATA) {
3519	ret = btrfs_add_delayed_tree_ref(trans, generic_ref: ref, NULL);
3520	} else {
3521	ret = btrfs_add_delayed_data_ref(trans, generic_ref: ref, reserved: 0);
3522	}
3523
3524	if (!((ref->type == BTRFS_REF_METADATA &&
3525	ref->tree_ref.ref_root == BTRFS_TREE_LOG_OBJECTID) ||
3526	(ref->type == BTRFS_REF_DATA &&
3527	ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
3528	btrfs_ref_tree_mod(fs_info, generic_ref: ref);
3529
3530	return ret;
3531	}
3532
3533	enum btrfs_loop_type {
3534	/*
3535	* Start caching block groups but do not wait for progress or for them
3536	* to be done.
3537	*/
3538	LOOP_CACHING_NOWAIT,
3539
3540	/*
3541	* Wait for the block group free_space >= the space we're waiting for if
3542	* the block group isn't cached.
3543	*/
3544	LOOP_CACHING_WAIT,
3545
3546	/*
3547	* Allow allocations to happen from block groups that do not yet have a
3548	* size classification.
3549	*/
3550	LOOP_UNSET_SIZE_CLASS,
3551
3552	/*
3553	* Allocate a chunk and then retry the allocation.
3554	*/
3555	LOOP_ALLOC_CHUNK,
3556
3557	/*
3558	* Ignore the size class restrictions for this allocation.
3559	*/
3560	LOOP_WRONG_SIZE_CLASS,
3561
3562	/*
3563	* Ignore the empty size, only try to allocate the number of bytes
3564	* needed for this allocation.
3565	*/
3566	LOOP_NO_EMPTY_SIZE,
3567	};
3568
3569	static inline void
3570	btrfs_lock_block_group(struct btrfs_block_group *cache,
3571	int delalloc)
3572	{
3573	if (delalloc)
3574	down_read(sem: &cache->data_rwsem);
3575	}
3576
3577	static inline void btrfs_grab_block_group(struct btrfs_block_group *cache,
3578	int delalloc)
3579	{
3580	btrfs_get_block_group(cache);
3581	if (delalloc)
3582	down_read(sem: &cache->data_rwsem);
3583	}
3584
3585	static struct btrfs_block_group *btrfs_lock_cluster(
3586	struct btrfs_block_group *block_group,
3587	struct btrfs_free_cluster *cluster,
3588	int delalloc)
3589	__acquires(&cluster->refill_lock)
3590	{
3591	struct btrfs_block_group *used_bg = NULL;
3592
3593	spin_lock(lock: &cluster->refill_lock);
3594	while (1) {
3595	used_bg = cluster->block_group;
3596	if (!used_bg)
3597	return NULL;
3598
3599	if (used_bg == block_group)
3600	return used_bg;
3601
3602	btrfs_get_block_group(cache: used_bg);
3603
3604	if (!delalloc)
3605	return used_bg;
3606
3607	if (down_read_trylock(sem: &used_bg->data_rwsem))
3608	return used_bg;
3609
3610	spin_unlock(lock: &cluster->refill_lock);
3611
3612	/* We should only have one-level nested. */
3613	down_read_nested(sem: &used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
3614
3615	spin_lock(lock: &cluster->refill_lock);
3616	if (used_bg == cluster->block_group)
3617	return used_bg;
3618
3619	up_read(sem: &used_bg->data_rwsem);
3620	btrfs_put_block_group(cache: used_bg);
3621	}
3622	}
3623
3624	static inline void
3625	btrfs_release_block_group(struct btrfs_block_group *cache,
3626	int delalloc)
3627	{
3628	if (delalloc)
3629	up_read(sem: &cache->data_rwsem);
3630	btrfs_put_block_group(cache);
3631	}
3632
3633	/*
3634	* Helper function for find_free_extent().
3635	*
3636	* Return -ENOENT to inform caller that we need fallback to unclustered mode.
3637	* Return >0 to inform caller that we find nothing
3638	* Return 0 means we have found a location and set ffe_ctl->found_offset.
3639	*/
3640	static int find_free_extent_clustered(struct btrfs_block_group *bg,
3641	struct find_free_extent_ctl *ffe_ctl,
3642	struct btrfs_block_group **cluster_bg_ret)
3643	{
3644	struct btrfs_block_group *cluster_bg;
3645	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3646	u64 aligned_cluster;
3647	u64 offset;
3648	int ret;
3649
3650	cluster_bg = btrfs_lock_cluster(block_group: bg, cluster: last_ptr, delalloc: ffe_ctl->delalloc);
3651	if (!cluster_bg)
3652	goto refill_cluster;
3653	if (cluster_bg != bg && (cluster_bg->ro ||
3654	!block_group_bits(cache: cluster_bg, bits: ffe_ctl->flags)))
3655	goto release_cluster;
3656
3657	offset = btrfs_alloc_from_cluster(block_group: cluster_bg, cluster: last_ptr,
3658	bytes: ffe_ctl->num_bytes, min_start: cluster_bg->start,
3659	max_extent_size: &ffe_ctl->max_extent_size);
3660	if (offset) {
3661	/* We have a block, we're done */
3662	spin_unlock(lock: &last_ptr->refill_lock);
3663	trace_btrfs_reserve_extent_cluster(block_group: cluster_bg, ffe_ctl);
3664	*cluster_bg_ret = cluster_bg;
3665	ffe_ctl->found_offset = offset;
3666	return 0;
3667	}
3668	WARN_ON(last_ptr->block_group != cluster_bg);
3669
3670	release_cluster:
3671	/*
3672	* If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
3673	* lets just skip it and let the allocator find whatever block it can
3674	* find. If we reach this point, we will have tried the cluster
3675	* allocator plenty of times and not have found anything, so we are
3676	* likely way too fragmented for the clustering stuff to find anything.
3677	*
3678	* However, if the cluster is taken from the current block group,
3679	* release the cluster first, so that we stand a better chance of
3680	* succeeding in the unclustered allocation.
3681	*/
3682	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
3683	spin_unlock(lock: &last_ptr->refill_lock);
3684	btrfs_release_block_group(cache: cluster_bg, delalloc: ffe_ctl->delalloc);
3685	return -ENOENT;
3686	}
3687
3688	/* This cluster didn't work out, free it and start over */
3689	btrfs_return_cluster_to_free_space(NULL, cluster: last_ptr);
3690
3691	if (cluster_bg != bg)
3692	btrfs_release_block_group(cache: cluster_bg, delalloc: ffe_ctl->delalloc);
3693
3694	refill_cluster:
3695	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
3696	spin_unlock(lock: &last_ptr->refill_lock);
3697	return -ENOENT;
3698	}
3699
3700	aligned_cluster = max_t(u64,
3701	ffe_ctl->empty_cluster + ffe_ctl->empty_size,
3702	bg->full_stripe_len);
3703	ret = btrfs_find_space_cluster(block_group: bg, cluster: last_ptr, offset: ffe_ctl->search_start,
3704	bytes: ffe_ctl->num_bytes, empty_size: aligned_cluster);
3705	if (ret == 0) {
3706	/* Now pull our allocation out of this cluster */
3707	offset = btrfs_alloc_from_cluster(block_group: bg, cluster: last_ptr,
3708	bytes: ffe_ctl->num_bytes, min_start: ffe_ctl->search_start,
3709	max_extent_size: &ffe_ctl->max_extent_size);
3710	if (offset) {
3711	/* We found one, proceed */
3712	spin_unlock(lock: &last_ptr->refill_lock);
3713	ffe_ctl->found_offset = offset;
3714	trace_btrfs_reserve_extent_cluster(block_group: bg, ffe_ctl);
3715	return 0;
3716	}
3717	}
3718	/*
3719	* At this point we either didn't find a cluster or we weren't able to
3720	* allocate a block from our cluster. Free the cluster we've been
3721	* trying to use, and go to the next block group.
3722	*/
3723	btrfs_return_cluster_to_free_space(NULL, cluster: last_ptr);
3724	spin_unlock(lock: &last_ptr->refill_lock);
3725	return 1;
3726	}
3727
3728	/*
3729	* Return >0 to inform caller that we find nothing
3730	* Return 0 when we found an free extent and set ffe_ctrl->found_offset
3731	*/
3732	static int find_free_extent_unclustered(struct btrfs_block_group *bg,
3733	struct find_free_extent_ctl *ffe_ctl)
3734	{
3735	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3736	u64 offset;
3737
3738	/*
3739	* We are doing an unclustered allocation, set the fragmented flag so
3740	* we don't bother trying to setup a cluster again until we get more
3741	* space.
3742	*/
3743	if (unlikely(last_ptr)) {
3744	spin_lock(lock: &last_ptr->lock);
3745	last_ptr->fragmented = 1;
3746	spin_unlock(lock: &last_ptr->lock);
3747	}
3748	if (ffe_ctl->cached) {
3749	struct btrfs_free_space_ctl *free_space_ctl;
3750
3751	free_space_ctl = bg->free_space_ctl;
3752	spin_lock(lock: &free_space_ctl->tree_lock);
3753	if (free_space_ctl->free_space <
3754	ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
3755	ffe_ctl->empty_size) {
3756	ffe_ctl->total_free_space = max_t(u64,
3757	ffe_ctl->total_free_space,
3758	free_space_ctl->free_space);
3759	spin_unlock(lock: &free_space_ctl->tree_lock);
3760	return 1;
3761	}
3762	spin_unlock(lock: &free_space_ctl->tree_lock);
3763	}
3764
3765	offset = btrfs_find_space_for_alloc(block_group: bg, offset: ffe_ctl->search_start,
3766	bytes: ffe_ctl->num_bytes, empty_size: ffe_ctl->empty_size,
3767	max_extent_size: &ffe_ctl->max_extent_size);
3768	if (!offset)
3769	return 1;
3770	ffe_ctl->found_offset = offset;
3771	return 0;
3772	}
3773
3774	static int do_allocation_clustered(struct btrfs_block_group *block_group,
3775	struct find_free_extent_ctl *ffe_ctl,
3776	struct btrfs_block_group **bg_ret)
3777	{
3778	int ret;
3779
3780	/* We want to try and use the cluster allocator, so lets look there */
3781	if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) {
3782	ret = find_free_extent_clustered(bg: block_group, ffe_ctl, cluster_bg_ret: bg_ret);
3783	if (ret >= 0)
3784	return ret;
3785	/* ret == -ENOENT case falls through */
3786	}
3787
3788	return find_free_extent_unclustered(bg: block_group, ffe_ctl);
3789	}
3790
3791	/*
3792	* Tree-log block group locking
3793	* ============================
3794	*
3795	* fs_info::treelog_bg_lock protects the fs_info::treelog_bg which
3796	* indicates the starting address of a block group, which is reserved only
3797	* for tree-log metadata.
3798	*
3799	* Lock nesting
3800	* ============
3801	*
3802	* space_info::lock
3803	* block_group::lock
3804	* fs_info::treelog_bg_lock
3805	*/
3806
3807	/*
3808	* Simple allocator for sequential-only block group. It only allows sequential
3809	* allocation. No need to play with trees. This function also reserves the
3810	* bytes as in btrfs_add_reserved_bytes.
3811	*/
3812	static int do_allocation_zoned(struct btrfs_block_group *block_group,
3813	struct find_free_extent_ctl *ffe_ctl,
3814	struct btrfs_block_group **bg_ret)
3815	{
3816	struct btrfs_fs_info *fs_info = block_group->fs_info;
3817	struct btrfs_space_info *space_info = block_group->space_info;
3818	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3819	u64 start = block_group->start;
3820	u64 num_bytes = ffe_ctl->num_bytes;
3821	u64 avail;
3822	u64 bytenr = block_group->start;
3823	u64 log_bytenr;
3824	u64 data_reloc_bytenr;
3825	int ret = 0;
3826	bool skip = false;
3827
3828	ASSERT(btrfs_is_zoned(block_group->fs_info));
3829
3830	/*
3831	* Do not allow non-tree-log blocks in the dedicated tree-log block
3832	* group, and vice versa.
3833	*/
3834	spin_lock(lock: &fs_info->treelog_bg_lock);
3835	log_bytenr = fs_info->treelog_bg;
3836	if (log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||
3837	(!ffe_ctl->for_treelog && bytenr == log_bytenr)))
3838	skip = true;
3839	spin_unlock(lock: &fs_info->treelog_bg_lock);
3840	if (skip)
3841	return 1;
3842
3843	/*
3844	* Do not allow non-relocation blocks in the dedicated relocation block
3845	* group, and vice versa.
3846	*/
3847	spin_lock(lock: &fs_info->relocation_bg_lock);
3848	data_reloc_bytenr = fs_info->data_reloc_bg;
3849	if (data_reloc_bytenr &&
3850	((ffe_ctl->for_data_reloc && bytenr != data_reloc_bytenr) ||
3851	(!ffe_ctl->for_data_reloc && bytenr == data_reloc_bytenr)))
3852	skip = true;
3853	spin_unlock(lock: &fs_info->relocation_bg_lock);
3854	if (skip)
3855	return 1;
3856
3857	/* Check RO and no space case before trying to activate it */
3858	spin_lock(lock: &block_group->lock);
3859	if (block_group->ro || btrfs_zoned_bg_is_full(bg: block_group)) {
3860	ret = 1;
3861	/*
3862	* May need to clear fs_info->{treelog,data_reloc}_bg.
3863	* Return the error after taking the locks.
3864	*/
3865	}
3866	spin_unlock(lock: &block_group->lock);
3867
3868	/* Metadata block group is activated at write time. */
3869	if (!ret && (block_group->flags & BTRFS_BLOCK_GROUP_DATA) &&
3870	!btrfs_zone_activate(block_group)) {
3871	ret = 1;
3872	/*
3873	* May need to clear fs_info->{treelog,data_reloc}_bg.
3874	* Return the error after taking the locks.
3875	*/
3876	}
3877
3878	spin_lock(lock: &space_info->lock);
3879	spin_lock(lock: &block_group->lock);
3880	spin_lock(lock: &fs_info->treelog_bg_lock);
3881	spin_lock(lock: &fs_info->relocation_bg_lock);
3882
3883	if (ret)
3884	goto out;
3885
3886	ASSERT(!ffe_ctl->for_treelog ||
3887	block_group->start == fs_info->treelog_bg ||
3888	fs_info->treelog_bg == 0);
3889	ASSERT(!ffe_ctl->for_data_reloc ||
3890	block_group->start == fs_info->data_reloc_bg ||
3891	fs_info->data_reloc_bg == 0);
3892
3893	if (block_group->ro ||
3894	(!ffe_ctl->for_data_reloc &&
3895	test_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags))) {
3896	ret = 1;
3897	goto out;
3898	}
3899
3900	/*
3901	* Do not allow currently using block group to be tree-log dedicated
3902	* block group.
3903	*/
3904	if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&
3905	(block_group->used || block_group->reserved)) {
3906	ret = 1;
3907	goto out;
3908	}
3909
3910	/*
3911	* Do not allow currently used block group to be the data relocation
3912	* dedicated block group.
3913	*/
3914	if (ffe_ctl->for_data_reloc && !fs_info->data_reloc_bg &&
3915	(block_group->used || block_group->reserved)) {
3916	ret = 1;
3917	goto out;
3918	}
3919
3920	WARN_ON_ONCE(block_group->alloc_offset > block_group->zone_capacity);
3921	avail = block_group->zone_capacity - block_group->alloc_offset;
3922	if (avail < num_bytes) {
3923	if (ffe_ctl->max_extent_size < avail) {
3924	/*
3925	* With sequential allocator, free space is always
3926	* contiguous
3927	*/
3928	ffe_ctl->max_extent_size = avail;
3929	ffe_ctl->total_free_space = avail;
3930	}
3931	ret = 1;
3932	goto out;
3933	}
3934
3935	if (ffe_ctl->for_treelog && !fs_info->treelog_bg)
3936	fs_info->treelog_bg = block_group->start;
3937
3938	if (ffe_ctl->for_data_reloc) {
3939	if (!fs_info->data_reloc_bg)
3940	fs_info->data_reloc_bg = block_group->start;
3941	/*
3942	* Do not allow allocations from this block group, unless it is
3943	* for data relocation. Compared to increasing the ->ro, setting
3944	* the ->zoned_data_reloc_ongoing flag still allows nocow
3945	* writers to come in. See btrfs_inc_nocow_writers().
3946	*
3947	* We need to disable an allocation to avoid an allocation of
3948	* regular (non-relocation data) extent. With mix of relocation
3949	* extents and regular extents, we can dispatch WRITE commands
3950	* (for relocation extents) and ZONE APPEND commands (for
3951	* regular extents) at the same time to the same zone, which
3952	* easily break the write pointer.
3953	*
3954	* Also, this flag avoids this block group to be zone finished.
3955	*/
3956	set_bit(nr: BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, addr: &block_group->runtime_flags);
3957	}
3958
3959	ffe_ctl->found_offset = start + block_group->alloc_offset;
3960	block_group->alloc_offset += num_bytes;
3961	spin_lock(lock: &ctl->tree_lock);
3962	ctl->free_space -= num_bytes;
3963	spin_unlock(lock: &ctl->tree_lock);
3964
3965	/*
3966	* We do not check if found_offset is aligned to stripesize. The
3967	* address is anyway rewritten when using zone append writing.
3968	*/
3969
3970	ffe_ctl->search_start = ffe_ctl->found_offset;
3971
3972	out:
3973	if (ret && ffe_ctl->for_treelog)
3974	fs_info->treelog_bg = 0;
3975	if (ret && ffe_ctl->for_data_reloc)
3976	fs_info->data_reloc_bg = 0;
3977	spin_unlock(lock: &fs_info->relocation_bg_lock);
3978	spin_unlock(lock: &fs_info->treelog_bg_lock);
3979	spin_unlock(lock: &block_group->lock);
3980	spin_unlock(lock: &space_info->lock);
3981	return ret;
3982	}
3983
3984	static int do_allocation(struct btrfs_block_group *block_group,
3985	struct find_free_extent_ctl *ffe_ctl,
3986	struct btrfs_block_group **bg_ret)
3987	{
3988	switch (ffe_ctl->policy) {
3989	case BTRFS_EXTENT_ALLOC_CLUSTERED:
3990	return do_allocation_clustered(block_group, ffe_ctl, bg_ret);
3991	case BTRFS_EXTENT_ALLOC_ZONED:
3992	return do_allocation_zoned(block_group, ffe_ctl, bg_ret);
3993	default:
3994	BUG();
3995	}
3996	}
3997
3998	static void release_block_group(struct btrfs_block_group *block_group,
3999	struct find_free_extent_ctl *ffe_ctl,
4000	int delalloc)
4001	{
4002	switch (ffe_ctl->policy) {
4003	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4004	ffe_ctl->retry_uncached = false;
4005	break;
4006	case BTRFS_EXTENT_ALLOC_ZONED:
4007	/* Nothing to do */
4008	break;
4009	default:
4010	BUG();
4011	}
4012
4013	BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
4014	ffe_ctl->index);
4015	btrfs_release_block_group(cache: block_group, delalloc);
4016	}
4017
4018	static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl,
4019	struct btrfs_key *ins)
4020	{
4021	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
4022
4023	if (!ffe_ctl->use_cluster && last_ptr) {
4024	spin_lock(lock: &last_ptr->lock);
4025	last_ptr->window_start = ins->objectid;
4026	spin_unlock(lock: &last_ptr->lock);
4027	}
4028	}
4029
4030	static void found_extent(struct find_free_extent_ctl *ffe_ctl,
4031	struct btrfs_key *ins)
4032	{
4033	switch (ffe_ctl->policy) {
4034	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4035	found_extent_clustered(ffe_ctl, ins);
4036	break;
4037	case BTRFS_EXTENT_ALLOC_ZONED:
4038	/* Nothing to do */
4039	break;
4040	default:
4041	BUG();
4042	}
4043	}
4044
4045	static int can_allocate_chunk_zoned(struct btrfs_fs_info *fs_info,
4046	struct find_free_extent_ctl *ffe_ctl)
4047	{
4048	/* Block group's activeness is not a requirement for METADATA block groups. */
4049	if (!(ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA))
4050	return 0;
4051
4052	/* If we can activate new zone, just allocate a chunk and use it */
4053	if (btrfs_can_activate_zone(fs_devices: fs_info->fs_devices, flags: ffe_ctl->flags))
4054	return 0;
4055
4056	/*
4057	* We already reached the max active zones. Try to finish one block
4058	* group to make a room for a new block group. This is only possible
4059	* for a data block group because btrfs_zone_finish() may need to wait
4060	* for a running transaction which can cause a deadlock for metadata
4061	* allocation.
4062	*/
4063	if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {
4064	int ret = btrfs_zone_finish_one_bg(fs_info);
4065
4066	if (ret == 1)
4067	return 0;
4068	else if (ret < 0)
4069	return ret;
4070	}
4071
4072	/*
4073	* If we have enough free space left in an already active block group
4074	* and we can't activate any other zone now, do not allow allocating a
4075	* new chunk and let find_free_extent() retry with a smaller size.
4076	*/
4077	if (ffe_ctl->max_extent_size >= ffe_ctl->min_alloc_size)
4078	return -ENOSPC;
4079
4080	/*
4081	* Even min_alloc_size is not left in any block groups. Since we cannot
4082	* activate a new block group, allocating it may not help. Let's tell a
4083	* caller to try again and hope it progress something by writing some
4084	* parts of the region. That is only possible for data block groups,
4085	* where a part of the region can be written.
4086	*/
4087	if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA)
4088	return -EAGAIN;
4089
4090	/*
4091	* We cannot activate a new block group and no enough space left in any
4092	* block groups. So, allocating a new block group may not help. But,
4093	* there is nothing to do anyway, so let's go with it.
4094	*/
4095	return 0;
4096	}
4097
4098	static int can_allocate_chunk(struct btrfs_fs_info *fs_info,
4099	struct find_free_extent_ctl *ffe_ctl)
4100	{
4101	switch (ffe_ctl->policy) {
4102	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4103	return 0;
4104	case BTRFS_EXTENT_ALLOC_ZONED:
4105	return can_allocate_chunk_zoned(fs_info, ffe_ctl);
4106	default:
4107	BUG();
4108	}
4109	}
4110
4111	/*
4112	* Return >0 means caller needs to re-search for free extent
4113	* Return 0 means we have the needed free extent.
4114	* Return <0 means we failed to locate any free extent.
4115	*/
4116	static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
4117	struct btrfs_key *ins,
4118	struct find_free_extent_ctl *ffe_ctl,
4119	bool full_search)
4120	{
4121	struct btrfs_root *root = fs_info->chunk_root;
4122	int ret;
4123
4124	if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
4125	ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
4126	ffe_ctl->orig_have_caching_bg = true;
4127
4128	if (ins->objectid) {
4129	found_extent(ffe_ctl, ins);
4130	return 0;
4131	}
4132
4133	if (ffe_ctl->loop >= LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
4134	return 1;
4135
4136	ffe_ctl->index++;
4137	if (ffe_ctl->index < BTRFS_NR_RAID_TYPES)
4138	return 1;
4139
4140	/* See the comments for btrfs_loop_type for an explanation of the phases. */
4141	if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
4142	ffe_ctl->index = 0;
4143	/*
4144	* We want to skip the LOOP_CACHING_WAIT step if we don't have
4145	* any uncached bgs and we've already done a full search
4146	* through.
4147	*/
4148	if (ffe_ctl->loop == LOOP_CACHING_NOWAIT &&
4149	(!ffe_ctl->orig_have_caching_bg && full_search))
4150	ffe_ctl->loop++;
4151	ffe_ctl->loop++;
4152
4153	if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
4154	struct btrfs_trans_handle *trans;
4155	int exist = 0;
4156
4157	/* Check if allocation policy allows to create a new chunk */
4158	ret = can_allocate_chunk(fs_info, ffe_ctl);
4159	if (ret)
4160	return ret;
4161
4162	trans = current->journal_info;
4163	if (trans)
4164	exist = 1;
4165	else
4166	trans = btrfs_join_transaction(root);
4167
4168	if (IS_ERR(ptr: trans)) {
4169	ret = PTR_ERR(ptr: trans);
4170	return ret;
4171	}
4172
4173	ret = btrfs_chunk_alloc(trans, flags: ffe_ctl->flags,
4174	force: CHUNK_ALLOC_FORCE_FOR_EXTENT);
4175
4176	/* Do not bail out on ENOSPC since we can do more. */
4177	if (ret == -ENOSPC) {
4178	ret = 0;
4179	ffe_ctl->loop++;
4180	}
4181	else if (ret < 0)
4182	btrfs_abort_transaction(trans, ret);
4183	else
4184	ret = 0;
4185	if (!exist)
4186	btrfs_end_transaction(trans);
4187	if (ret)
4188	return ret;
4189	}
4190
4191	if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
4192	if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED)
4193	return -ENOSPC;
4194
4195	/*
4196	* Don't loop again if we already have no empty_size and
4197	* no empty_cluster.
4198	*/
4199	if (ffe_ctl->empty_size == 0 &&
4200	ffe_ctl->empty_cluster == 0)
4201	return -ENOSPC;
4202	ffe_ctl->empty_size = 0;
4203	ffe_ctl->empty_cluster = 0;
4204	}
4205	return 1;
4206	}
4207	return -ENOSPC;
4208	}
4209
4210	static bool find_free_extent_check_size_class(struct find_free_extent_ctl *ffe_ctl,
4211	struct btrfs_block_group *bg)
4212	{
4213	if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED)
4214	return true;
4215	if (!btrfs_block_group_should_use_size_class(bg))
4216	return true;
4217	if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS)
4218	return true;
4219	if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS &&
4220	bg->size_class == BTRFS_BG_SZ_NONE)
4221	return true;
4222	return ffe_ctl->size_class == bg->size_class;
4223	}
4224
4225	static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info,
4226	struct find_free_extent_ctl *ffe_ctl,
4227	struct btrfs_space_info *space_info,
4228	struct btrfs_key *ins)
4229	{
4230	/*
4231	* If our free space is heavily fragmented we may not be able to make
4232	* big contiguous allocations, so instead of doing the expensive search
4233	* for free space, simply return ENOSPC with our max_extent_size so we
4234	* can go ahead and search for a more manageable chunk.
4235	*
4236	* If our max_extent_size is large enough for our allocation simply
4237	* disable clustering since we will likely not be able to find enough
4238	* space to create a cluster and induce latency trying.
4239	*/
4240	if (space_info->max_extent_size) {
4241	spin_lock(lock: &space_info->lock);
4242	if (space_info->max_extent_size &&
4243	ffe_ctl->num_bytes > space_info->max_extent_size) {
4244	ins->offset = space_info->max_extent_size;
4245	spin_unlock(lock: &space_info->lock);
4246	return -ENOSPC;
4247	} else if (space_info->max_extent_size) {
4248	ffe_ctl->use_cluster = false;
4249	}
4250	spin_unlock(lock: &space_info->lock);
4251	}
4252
4253	ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info,
4254	empty_cluster: &ffe_ctl->empty_cluster);
4255	if (ffe_ctl->last_ptr) {
4256	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
4257
4258	spin_lock(lock: &last_ptr->lock);
4259	if (last_ptr->block_group)
4260	ffe_ctl->hint_byte = last_ptr->window_start;
4261	if (last_ptr->fragmented) {
4262	/*
4263	* We still set window_start so we can keep track of the
4264	* last place we found an allocation to try and save
4265	* some time.
4266	*/
4267	ffe_ctl->hint_byte = last_ptr->window_start;
4268	ffe_ctl->use_cluster = false;
4269	}
4270	spin_unlock(lock: &last_ptr->lock);
4271	}
4272
4273	return 0;
4274	}
4275
4276	static int prepare_allocation(struct btrfs_fs_info *fs_info,
4277	struct find_free_extent_ctl *ffe_ctl,
4278	struct btrfs_space_info *space_info,
4279	struct btrfs_key *ins)
4280	{
4281	switch (ffe_ctl->policy) {
4282	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4283	return prepare_allocation_clustered(fs_info, ffe_ctl,
4284	space_info, ins);
4285	case BTRFS_EXTENT_ALLOC_ZONED:
4286	if (ffe_ctl->for_treelog) {
4287	spin_lock(lock: &fs_info->treelog_bg_lock);
4288	if (fs_info->treelog_bg)
4289	ffe_ctl->hint_byte = fs_info->treelog_bg;
4290	spin_unlock(lock: &fs_info->treelog_bg_lock);
4291	}
4292	if (ffe_ctl->for_data_reloc) {
4293	spin_lock(lock: &fs_info->relocation_bg_lock);
4294	if (fs_info->data_reloc_bg)
4295	ffe_ctl->hint_byte = fs_info->data_reloc_bg;
4296	spin_unlock(lock: &fs_info->relocation_bg_lock);
4297	}
4298	return 0;
4299	default:
4300	BUG();
4301	}
4302	}
4303
4304	/*
4305	* walks the btree of allocated extents and find a hole of a given size.
4306	* The key ins is changed to record the hole:
4307	* ins->objectid == start position
4308	* ins->flags = BTRFS_EXTENT_ITEM_KEY
4309	* ins->offset == the size of the hole.
4310	* Any available blocks before search_start are skipped.
4311	*
4312	* If there is no suitable free space, we will record the max size of
4313	* the free space extent currently.
4314	*
4315	* The overall logic and call chain:
4316	*
4317	* find_free_extent()
4318	* |- Iterate through all block groups
4319	* | |- Get a valid block group
4320	* | |- Try to do clustered allocation in that block group
4321	* | |- Try to do unclustered allocation in that block group
4322	* | |- Check if the result is valid
4323	* | | |- If valid, then exit
4324	* | |- Jump to next block group
4325	* |
4326	* |- Push harder to find free extents
4327	* |- If not found, re-iterate all block groups
4328	*/
4329	static noinline int find_free_extent(struct btrfs_root *root,
4330	struct btrfs_key *ins,
4331	struct find_free_extent_ctl *ffe_ctl)
4332	{
4333	struct btrfs_fs_info *fs_info = root->fs_info;
4334	int ret = 0;
4335	int cache_block_group_error = 0;
4336	struct btrfs_block_group *block_group = NULL;
4337	struct btrfs_space_info *space_info;
4338	bool full_search = false;
4339
4340	WARN_ON(ffe_ctl->num_bytes < fs_info->sectorsize);
4341
4342	ffe_ctl->search_start = 0;
4343	/* For clustered allocation */
4344	ffe_ctl->empty_cluster = 0;
4345	ffe_ctl->last_ptr = NULL;
4346	ffe_ctl->use_cluster = true;
4347	ffe_ctl->have_caching_bg = false;
4348	ffe_ctl->orig_have_caching_bg = false;
4349	ffe_ctl->index = btrfs_bg_flags_to_raid_index(flags: ffe_ctl->flags);
4350	ffe_ctl->loop = 0;
4351	ffe_ctl->retry_uncached = false;
4352	ffe_ctl->cached = 0;
4353	ffe_ctl->max_extent_size = 0;
4354	ffe_ctl->total_free_space = 0;
4355	ffe_ctl->found_offset = 0;
4356	ffe_ctl->policy = BTRFS_EXTENT_ALLOC_CLUSTERED;
4357	ffe_ctl->size_class = btrfs_calc_block_group_size_class(size: ffe_ctl->num_bytes);
4358
4359	if (btrfs_is_zoned(fs_info))
4360	ffe_ctl->policy = BTRFS_EXTENT_ALLOC_ZONED;
4361
4362	ins->type = BTRFS_EXTENT_ITEM_KEY;
4363	ins->objectid = 0;
4364	ins->offset = 0;
4365
4366	trace_find_free_extent(root, ffe_ctl);
4367
4368	space_info = btrfs_find_space_info(info: fs_info, flags: ffe_ctl->flags);
4369	if (!space_info) {
4370	btrfs_err(fs_info, "No space info for %llu", ffe_ctl->flags);
4371	return -ENOSPC;
4372	}
4373
4374	ret = prepare_allocation(fs_info, ffe_ctl, space_info, ins);
4375	if (ret < 0)
4376	return ret;
4377
4378	ffe_ctl->search_start = max(ffe_ctl->search_start,
4379	first_logical_byte(fs_info));
4380	ffe_ctl->search_start = max(ffe_ctl->search_start, ffe_ctl->hint_byte);
4381	if (ffe_ctl->search_start == ffe_ctl->hint_byte) {
4382	block_group = btrfs_lookup_block_group(info: fs_info,
4383	bytenr: ffe_ctl->search_start);
4384	/*
4385	* we don't want to use the block group if it doesn't match our
4386	* allocation bits, or if its not cached.
4387	*
4388	* However if we are re-searching with an ideal block group
4389	* picked out then we don't care that the block group is cached.
4390	*/
4391	if (block_group && block_group_bits(cache: block_group, bits: ffe_ctl->flags) &&
4392	block_group->cached != BTRFS_CACHE_NO) {
4393	down_read(sem: &space_info->groups_sem);
4394	if (list_empty(head: &block_group->list) ||
4395	block_group->ro) {
4396	/*
4397	* someone is removing this block group,
4398	* we can't jump into the have_block_group
4399	* target because our list pointers are not
4400	* valid
4401	*/
4402	btrfs_put_block_group(cache: block_group);
4403	up_read(sem: &space_info->groups_sem);
4404	} else {
4405	ffe_ctl->index = btrfs_bg_flags_to_raid_index(
4406	flags: block_group->flags);
4407	btrfs_lock_block_group(cache: block_group,
4408	delalloc: ffe_ctl->delalloc);
4409	ffe_ctl->hinted = true;
4410	goto have_block_group;
4411	}
4412	} else if (block_group) {
4413	btrfs_put_block_group(cache: block_group);
4414	}
4415	}
4416	search:
4417	trace_find_free_extent_search_loop(root, ffe_ctl);
4418	ffe_ctl->have_caching_bg = false;
4419	if (ffe_ctl->index == btrfs_bg_flags_to_raid_index(flags: ffe_ctl->flags) ||
4420	ffe_ctl->index == 0)
4421	full_search = true;
4422	down_read(sem: &space_info->groups_sem);
4423	list_for_each_entry(block_group,
4424	&space_info->block_groups[ffe_ctl->index], list) {
4425	struct btrfs_block_group *bg_ret;
4426
4427	ffe_ctl->hinted = false;
4428	/* If the block group is read-only, we can skip it entirely. */
4429	if (unlikely(block_group->ro)) {
4430	if (ffe_ctl->for_treelog)
4431	btrfs_clear_treelog_bg(bg: block_group);
4432	if (ffe_ctl->for_data_reloc)
4433	btrfs_clear_data_reloc_bg(bg: block_group);
4434	continue;
4435	}
4436
4437	btrfs_grab_block_group(cache: block_group, delalloc: ffe_ctl->delalloc);
4438	ffe_ctl->search_start = block_group->start;
4439
4440	/*
4441	* this can happen if we end up cycling through all the
4442	* raid types, but we want to make sure we only allocate
4443	* for the proper type.
4444	*/
4445	if (!block_group_bits(cache: block_group, bits: ffe_ctl->flags)) {
4446	u64 extra = BTRFS_BLOCK_GROUP_DUP |
4447	BTRFS_BLOCK_GROUP_RAID1_MASK |
4448	BTRFS_BLOCK_GROUP_RAID56_MASK |
4449	BTRFS_BLOCK_GROUP_RAID10;
4450
4451	/*
4452	* if they asked for extra copies and this block group
4453	* doesn't provide them, bail. This does allow us to
4454	* fill raid0 from raid1.
4455	*/
4456	if ((ffe_ctl->flags & extra) && !(block_group->flags & extra))
4457	goto loop;
4458
4459	/*
4460	* This block group has different flags than we want.
4461	* It's possible that we have MIXED_GROUP flag but no
4462	* block group is mixed. Just skip such block group.
4463	*/
4464	btrfs_release_block_group(cache: block_group, delalloc: ffe_ctl->delalloc);
4465	continue;
4466	}
4467
4468	have_block_group:
4469	trace_find_free_extent_have_block_group(root, ffe_ctl, block_group);
4470	ffe_ctl->cached = btrfs_block_group_done(cache: block_group);
4471	if (unlikely(!ffe_ctl->cached)) {
4472	ffe_ctl->have_caching_bg = true;
4473	ret = btrfs_cache_block_group(cache: block_group, wait: false);
4474
4475	/*
4476	* If we get ENOMEM here or something else we want to
4477	* try other block groups, because it may not be fatal.
4478	* However if we can't find anything else we need to
4479	* save our return here so that we return the actual
4480	* error that caused problems, not ENOSPC.
4481	*/
4482	if (ret < 0) {
4483	if (!cache_block_group_error)
4484	cache_block_group_error = ret;
4485	ret = 0;
4486	goto loop;
4487	}
4488	ret = 0;
4489	}
4490
4491	if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) {
4492	if (!cache_block_group_error)
4493	cache_block_group_error = -EIO;
4494	goto loop;
4495	}
4496
4497	if (!find_free_extent_check_size_class(ffe_ctl, bg: block_group))
4498	goto loop;
4499
4500	bg_ret = NULL;
4501	ret = do_allocation(block_group, ffe_ctl, bg_ret: &bg_ret);
4502	if (ret > 0)
4503	goto loop;
4504
4505	if (bg_ret && bg_ret != block_group) {
4506	btrfs_release_block_group(cache: block_group, delalloc: ffe_ctl->delalloc);
4507	block_group = bg_ret;
4508	}
4509
4510	/* Checks */
4511	ffe_ctl->search_start = round_up(ffe_ctl->found_offset,
4512	fs_info->stripesize);
4513
4514	/* move on to the next group */
4515	if (ffe_ctl->search_start + ffe_ctl->num_bytes >
4516	block_group->start + block_group->length) {
4517	btrfs_add_free_space_unused(block_group,
4518	bytenr: ffe_ctl->found_offset,
4519	size: ffe_ctl->num_bytes);
4520	goto loop;
4521	}
4522
4523	if (ffe_ctl->found_offset < ffe_ctl->search_start)
4524	btrfs_add_free_space_unused(block_group,
4525	bytenr: ffe_ctl->found_offset,
4526	size: ffe_ctl->search_start - ffe_ctl->found_offset);
4527
4528	ret = btrfs_add_reserved_bytes(cache: block_group, ram_bytes: ffe_ctl->ram_bytes,
4529	num_bytes: ffe_ctl->num_bytes,
4530	delalloc: ffe_ctl->delalloc,
4531	force_wrong_size_class: ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS);
4532	if (ret == -EAGAIN) {
4533	btrfs_add_free_space_unused(block_group,
4534	bytenr: ffe_ctl->found_offset,
4535	size: ffe_ctl->num_bytes);
4536	goto loop;
4537	}
4538	btrfs_inc_block_group_reservations(bg: block_group);
4539
4540	/* we are all good, lets return */
4541	ins->objectid = ffe_ctl->search_start;
4542	ins->offset = ffe_ctl->num_bytes;
4543
4544	trace_btrfs_reserve_extent(block_group, ffe_ctl);
4545	btrfs_release_block_group(cache: block_group, delalloc: ffe_ctl->delalloc);
4546	break;
4547	loop:
4548	if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
4549	!ffe_ctl->retry_uncached) {
4550	ffe_ctl->retry_uncached = true;
4551	btrfs_wait_block_group_cache_progress(cache: block_group,
4552	num_bytes: ffe_ctl->num_bytes +
4553	ffe_ctl->empty_cluster +
4554	ffe_ctl->empty_size);
4555	goto have_block_group;
4556	}
4557	release_block_group(block_group, ffe_ctl, delalloc: ffe_ctl->delalloc);
4558	cond_resched();
4559	}
4560	up_read(sem: &space_info->groups_sem);
4561
4562	ret = find_free_extent_update_loop(fs_info, ins, ffe_ctl, full_search);
4563	if (ret > 0)
4564	goto search;
4565
4566	if (ret == -ENOSPC && !cache_block_group_error) {
4567	/*
4568	* Use ffe_ctl->total_free_space as fallback if we can't find
4569	* any contiguous hole.
4570	*/
4571	if (!ffe_ctl->max_extent_size)
4572	ffe_ctl->max_extent_size = ffe_ctl->total_free_space;
4573	spin_lock(lock: &space_info->lock);
4574	space_info->max_extent_size = ffe_ctl->max_extent_size;
4575	spin_unlock(lock: &space_info->lock);
4576	ins->offset = ffe_ctl->max_extent_size;
4577	} else if (ret == -ENOSPC) {
4578	ret = cache_block_group_error;
4579	}
4580	return ret;
4581	}
4582
4583	/*
4584	* Entry point to the extent allocator. Tries to find a hole that is at least
4585	* as big as @num_bytes.
4586	*
4587	* @root - The root that will contain this extent
4588	*
4589	* @ram_bytes - The amount of space in ram that @num_bytes take. This
4590	* is used for accounting purposes. This value differs
4591	* from @num_bytes only in the case of compressed extents.
4592	*
4593	* @num_bytes - Number of bytes to allocate on-disk.
4594	*
4595	* @min_alloc_size - Indicates the minimum amount of space that the
4596	* allocator should try to satisfy. In some cases
4597	* @num_bytes may be larger than what is required and if
4598	* the filesystem is fragmented then allocation fails.
4599	* However, the presence of @min_alloc_size gives a
4600	* chance to try and satisfy the smaller allocation.
4601	*
4602	* @empty_size - A hint that you plan on doing more COW. This is the
4603	* size in bytes the allocator should try to find free
4604	* next to the block it returns. This is just a hint and
4605	* may be ignored by the allocator.
4606	*
4607	* @hint_byte - Hint to the allocator to start searching above the byte
4608	* address passed. It might be ignored.
4609	*
4610	* @ins - This key is modified to record the found hole. It will
4611	* have the following values:
4612	* ins->objectid == start position
4613	* ins->flags = BTRFS_EXTENT_ITEM_KEY
4614	* ins->offset == the size of the hole.
4615	*
4616	* @is_data - Boolean flag indicating whether an extent is
4617	* allocated for data (true) or metadata (false)
4618	*
4619	* @delalloc - Boolean flag indicating whether this allocation is for
4620	* delalloc or not. If 'true' data_rwsem of block groups
4621	* is going to be acquired.
4622	*
4623	*
4624	* Returns 0 when an allocation succeeded or < 0 when an error occurred. In
4625	* case -ENOSPC is returned then @ins->offset will contain the size of the
4626	* largest available hole the allocator managed to find.
4627	*/
4628	int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
4629	u64 num_bytes, u64 min_alloc_size,
4630	u64 empty_size, u64 hint_byte,
4631	struct btrfs_key *ins, int is_data, int delalloc)
4632	{
4633	struct btrfs_fs_info *fs_info = root->fs_info;
4634	struct find_free_extent_ctl ffe_ctl = {};
4635	bool final_tried = num_bytes == min_alloc_size;
4636	u64 flags;
4637	int ret;
4638	bool for_treelog = (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
4639	bool for_data_reloc = (btrfs_is_data_reloc_root(root) && is_data);
4640
4641	flags = get_alloc_profile_by_root(root, data: is_data);
4642	again:
4643	WARN_ON(num_bytes < fs_info->sectorsize);
4644
4645	ffe_ctl.ram_bytes = ram_bytes;
4646	ffe_ctl.num_bytes = num_bytes;
4647	ffe_ctl.min_alloc_size = min_alloc_size;
4648	ffe_ctl.empty_size = empty_size;
4649	ffe_ctl.flags = flags;
4650	ffe_ctl.delalloc = delalloc;
4651	ffe_ctl.hint_byte = hint_byte;
4652	ffe_ctl.for_treelog = for_treelog;
4653	ffe_ctl.for_data_reloc = for_data_reloc;
4654
4655	ret = find_free_extent(root, ins, ffe_ctl: &ffe_ctl);
4656	if (!ret && !is_data) {
4657	btrfs_dec_block_group_reservations(fs_info, start: ins->objectid);
4658	} else if (ret == -ENOSPC) {
4659	if (!final_tried && ins->offset) {
4660	num_bytes = min(num_bytes >> 1, ins->offset);
4661	num_bytes = round_down(num_bytes,
4662	fs_info->sectorsize);
4663	num_bytes = max(num_bytes, min_alloc_size);
4664	ram_bytes = num_bytes;
4665	if (num_bytes == min_alloc_size)
4666	final_tried = true;
4667	goto again;
4668	} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4669	struct btrfs_space_info *sinfo;
4670
4671	sinfo = btrfs_find_space_info(info: fs_info, flags);
4672	btrfs_err(fs_info,
4673	"allocation failed flags %llu, wanted %llu tree-log %d, relocation: %d",
4674	flags, num_bytes, for_treelog, for_data_reloc);
4675	if (sinfo)
4676	btrfs_dump_space_info(fs_info, info: sinfo,
4677	bytes: num_bytes, dump_block_groups: 1);
4678	}
4679	}
4680
4681	return ret;
4682	}
4683
4684	int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
4685	u64 start, u64 len, int delalloc)
4686	{
4687	struct btrfs_block_group *cache;
4688
4689	cache = btrfs_lookup_block_group(info: fs_info, bytenr: start);
4690	if (!cache) {
4691	btrfs_err(fs_info, "Unable to find block group for %llu",
4692	start);
4693	return -ENOSPC;
4694	}
4695
4696	btrfs_add_free_space(block_group: cache, bytenr: start, size: len);
4697	btrfs_free_reserved_bytes(cache, num_bytes: len, delalloc);
4698	trace_btrfs_reserved_extent_free(fs_info, start, len);
4699
4700	btrfs_put_block_group(cache);
4701	return 0;
4702	}
4703
4704	int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans,
4705	const struct extent_buffer *eb)
4706	{
4707	struct btrfs_block_group *cache;
4708	int ret = 0;
4709
4710	cache = btrfs_lookup_block_group(info: trans->fs_info, bytenr: eb->start);
4711	if (!cache) {
4712	btrfs_err(trans->fs_info, "unable to find block group for %llu",
4713	eb->start);
4714	return -ENOSPC;
4715	}
4716
4717	ret = pin_down_extent(trans, cache, bytenr: eb->start, num_bytes: eb->len, reserved: 1);
4718	btrfs_put_block_group(cache);
4719	return ret;
4720	}
4721
4722	static int alloc_reserved_extent(struct btrfs_trans_handle *trans, u64 bytenr,
4723	u64 num_bytes)
4724	{
4725	struct btrfs_fs_info *fs_info = trans->fs_info;
4726	int ret;
4727
4728	ret = remove_from_free_space_tree(trans, start: bytenr, size: num_bytes);
4729	if (ret)
4730	return ret;
4731
4732	ret = btrfs_update_block_group(trans, bytenr, num_bytes, alloc: true);
4733	if (ret) {
4734	ASSERT(!ret);
4735	btrfs_err(fs_info, "update block group failed for %llu %llu",
4736	bytenr, num_bytes);
4737	return ret;
4738	}
4739
4740	trace_btrfs_reserved_extent_alloc(fs_info, start: bytenr, len: num_bytes);
4741	return 0;
4742	}
4743
4744	static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4745	u64 parent, u64 root_objectid,
4746	u64 flags, u64 owner, u64 offset,
4747	struct btrfs_key *ins, int ref_mod, u64 oref_root)
4748	{
4749	struct btrfs_fs_info *fs_info = trans->fs_info;
4750	struct btrfs_root *extent_root;
4751	int ret;
4752	struct btrfs_extent_item *extent_item;
4753	struct btrfs_extent_owner_ref *oref;
4754	struct btrfs_extent_inline_ref *iref;
4755	struct btrfs_path *path;
4756	struct extent_buffer *leaf;
4757	int type;
4758	u32 size;
4759	const bool simple_quota = (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE);
4760
4761	if (parent > 0)
4762	type = BTRFS_SHARED_DATA_REF_KEY;
4763	else
4764	type = BTRFS_EXTENT_DATA_REF_KEY;
4765
4766	size = sizeof(*extent_item);
4767	if (simple_quota)
4768	size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
4769	size += btrfs_extent_inline_ref_size(type);
4770
4771	path = btrfs_alloc_path();
4772	if (!path)
4773	return -ENOMEM;
4774
4775	extent_root = btrfs_extent_root(fs_info, bytenr: ins->objectid);
4776	ret = btrfs_insert_empty_item(trans, root: extent_root, path, key: ins, data_size: size);
4777	if (ret) {
4778	btrfs_free_path(p: path);
4779	return ret;
4780	}
4781
4782	leaf = path->nodes[0];
4783	extent_item = btrfs_item_ptr(leaf, path->slots[0],
4784	struct btrfs_extent_item);
4785	btrfs_set_extent_refs(eb: leaf, s: extent_item, val: ref_mod);
4786	btrfs_set_extent_generation(eb: leaf, s: extent_item, val: trans->transid);
4787	btrfs_set_extent_flags(eb: leaf, s: extent_item,
4788	val: flags | BTRFS_EXTENT_FLAG_DATA);
4789
4790	iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4791	if (simple_quota) {
4792	btrfs_set_extent_inline_ref_type(eb: leaf, s: iref, BTRFS_EXTENT_OWNER_REF_KEY);
4793	oref = (struct btrfs_extent_owner_ref *)(&iref->offset);
4794	btrfs_set_extent_owner_ref_root_id(eb: leaf, s: oref, val: oref_root);
4795	iref = (struct btrfs_extent_inline_ref *)(oref + 1);
4796	}
4797	btrfs_set_extent_inline_ref_type(eb: leaf, s: iref, val: type);
4798
4799	if (parent > 0) {
4800	struct btrfs_shared_data_ref *ref;
4801	ref = (struct btrfs_shared_data_ref *)(iref + 1);
4802	btrfs_set_extent_inline_ref_offset(eb: leaf, s: iref, val: parent);
4803	btrfs_set_shared_data_ref_count(eb: leaf, s: ref, val: ref_mod);
4804	} else {
4805	struct btrfs_extent_data_ref *ref;
4806	ref = (struct btrfs_extent_data_ref *)(&iref->offset);
4807	btrfs_set_extent_data_ref_root(eb: leaf, s: ref, val: root_objectid);
4808	btrfs_set_extent_data_ref_objectid(eb: leaf, s: ref, val: owner);
4809	btrfs_set_extent_data_ref_offset(eb: leaf, s: ref, val: offset);
4810	btrfs_set_extent_data_ref_count(eb: leaf, s: ref, val: ref_mod);
4811	}
4812
4813	btrfs_mark_buffer_dirty(trans, buf: path->nodes[0]);
4814	btrfs_free_path(p: path);
4815
4816	return alloc_reserved_extent(trans, bytenr: ins->objectid, num_bytes: ins->offset);
4817	}
4818
4819	static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
4820	struct btrfs_delayed_ref_node *node,
4821	struct btrfs_delayed_extent_op *extent_op)
4822	{
4823	struct btrfs_fs_info *fs_info = trans->fs_info;
4824	struct btrfs_root *extent_root;
4825	int ret;
4826	struct btrfs_extent_item *extent_item;
4827	struct btrfs_key extent_key;
4828	struct btrfs_tree_block_info *block_info;
4829	struct btrfs_extent_inline_ref *iref;
4830	struct btrfs_path *path;
4831	struct extent_buffer *leaf;
4832	struct btrfs_delayed_tree_ref *ref;
4833	u32 size = sizeof(*extent_item) + sizeof(*iref);
4834	u64 flags = extent_op->flags_to_set;
4835	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4836
4837	ref = btrfs_delayed_node_to_tree_ref(node);
4838
4839	extent_key.objectid = node->bytenr;
4840	if (skinny_metadata) {
4841	extent_key.offset = ref->level;
4842	extent_key.type = BTRFS_METADATA_ITEM_KEY;
4843	} else {
4844	extent_key.offset = node->num_bytes;
4845	extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4846	size += sizeof(*block_info);
4847	}
4848
4849	path = btrfs_alloc_path();
4850	if (!path)
4851	return -ENOMEM;
4852
4853	extent_root = btrfs_extent_root(fs_info, bytenr: extent_key.objectid);
4854	ret = btrfs_insert_empty_item(trans, root: extent_root, path, key: &extent_key,
4855	data_size: size);
4856	if (ret) {
4857	btrfs_free_path(p: path);
4858	return ret;
4859	}
4860
4861	leaf = path->nodes[0];
4862	extent_item = btrfs_item_ptr(leaf, path->slots[0],
4863	struct btrfs_extent_item);
4864	btrfs_set_extent_refs(eb: leaf, s: extent_item, val: 1);
4865	btrfs_set_extent_generation(eb: leaf, s: extent_item, val: trans->transid);
4866	btrfs_set_extent_flags(eb: leaf, s: extent_item,
4867	val: flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
4868
4869	if (skinny_metadata) {
4870	iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4871	} else {
4872	block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
4873	btrfs_set_tree_block_key(eb: leaf, item: block_info, key: &extent_op->key);
4874	btrfs_set_tree_block_level(eb: leaf, s: block_info, val: ref->level);
4875	iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
4876	}
4877
4878	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
4879	btrfs_set_extent_inline_ref_type(eb: leaf, s: iref,
4880	BTRFS_SHARED_BLOCK_REF_KEY);
4881	btrfs_set_extent_inline_ref_offset(eb: leaf, s: iref, val: ref->parent);
4882	} else {
4883	btrfs_set_extent_inline_ref_type(eb: leaf, s: iref,
4884	BTRFS_TREE_BLOCK_REF_KEY);
4885	btrfs_set_extent_inline_ref_offset(eb: leaf, s: iref, val: ref->root);
4886	}
4887
4888	btrfs_mark_buffer_dirty(trans, buf: leaf);
4889	btrfs_free_path(p: path);
4890
4891	return alloc_reserved_extent(trans, bytenr: node->bytenr, num_bytes: fs_info->nodesize);
4892	}
4893
4894	int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4895	struct btrfs_root *root, u64 owner,
4896	u64 offset, u64 ram_bytes,
4897	struct btrfs_key *ins)
4898	{
4899	struct btrfs_ref generic_ref = { 0 };
4900	u64 root_objectid = root->root_key.objectid;
4901	u64 owning_root = root_objectid;
4902
4903	BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
4904
4905	if (btrfs_is_data_reloc_root(root) && is_fstree(rootid: root->relocation_src_root))
4906	owning_root = root->relocation_src_root;
4907
4908	btrfs_init_generic_ref(generic_ref: &generic_ref, action: BTRFS_ADD_DELAYED_EXTENT,
4909	bytenr: ins->objectid, len: ins->offset, parent: 0, owning_root);
4910	btrfs_init_data_ref(generic_ref: &generic_ref, ref_root: root_objectid, ino: owner,
4911	offset, mod_root: 0, skip_qgroup: false);
4912	btrfs_ref_tree_mod(fs_info: root->fs_info, generic_ref: &generic_ref);
4913
4914	return btrfs_add_delayed_data_ref(trans, generic_ref: &generic_ref, reserved: ram_bytes);
4915	}
4916
4917	/*
4918	* this is used by the tree logging recovery code. It records that
4919	* an extent has been allocated and makes sure to clear the free
4920	* space cache bits as well
4921	*/
4922	int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
4923	u64 root_objectid, u64 owner, u64 offset,
4924	struct btrfs_key *ins)
4925	{
4926	struct btrfs_fs_info *fs_info = trans->fs_info;
4927	int ret;
4928	struct btrfs_block_group *block_group;
4929	struct btrfs_space_info *space_info;
4930	struct btrfs_squota_delta delta = {
4931	.root = root_objectid,
4932	.num_bytes = ins->offset,
4933	.generation = trans->transid,
4934	.rsv_bytes = 0,
4935	.is_data = true,
4936	.is_inc = true,
4937	};
4938
4939	/*
4940	* Mixed block groups will exclude before processing the log so we only
4941	* need to do the exclude dance if this fs isn't mixed.
4942	*/
4943	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
4944	ret = __exclude_logged_extent(fs_info, start: ins->objectid,
4945	num_bytes: ins->offset);
4946	if (ret)
4947	return ret;
4948	}
4949
4950	block_group = btrfs_lookup_block_group(info: fs_info, bytenr: ins->objectid);
4951	if (!block_group)
4952	return -EINVAL;
4953
4954	space_info = block_group->space_info;
4955	spin_lock(lock: &space_info->lock);
4956	spin_lock(lock: &block_group->lock);
4957	space_info->bytes_reserved += ins->offset;
4958	block_group->reserved += ins->offset;
4959	spin_unlock(lock: &block_group->lock);
4960	spin_unlock(lock: &space_info->lock);
4961
4962	ret = alloc_reserved_file_extent(trans, parent: 0, root_objectid, flags: 0, owner,
4963	offset, ins, ref_mod: 1, oref_root: root_objectid);
4964	if (ret)
4965	btrfs_pin_extent(trans, bytenr: ins->objectid, num_bytes: ins->offset, reserved: 1);
4966	ret = btrfs_record_squota_delta(fs_info, delta: &delta);
4967	btrfs_put_block_group(cache: block_group);
4968	return ret;
4969	}
4970
4971	#ifdef CONFIG_BTRFS_DEBUG
4972	/*
4973	* Extra safety check in case the extent tree is corrupted and extent allocator
4974	* chooses to use a tree block which is already used and locked.
4975	*/
4976	static bool check_eb_lock_owner(const struct extent_buffer *eb)
4977	{
4978	if (eb->lock_owner == current->pid) {
4979	btrfs_err_rl(eb->fs_info,
4980	"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
4981	eb->start, btrfs_header_owner(eb), current->pid);
4982	return true;
4983	}
4984	return false;
4985	}
4986	#else
4987	static bool check_eb_lock_owner(struct extent_buffer *eb)
4988	{
4989	return false;
4990	}
4991	#endif
4992
4993	static struct extent_buffer *
4994	btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4995	u64 bytenr, int level, u64 owner,
4996	enum btrfs_lock_nesting nest)
4997	{
4998	struct btrfs_fs_info *fs_info = root->fs_info;
4999	struct extent_buffer *buf;
5000	u64 lockdep_owner = owner;
5001
5002	buf = btrfs_find_create_tree_block(fs_info, bytenr, owner_root: owner, level);
5003	if (IS_ERR(ptr: buf))
5004	return buf;
5005
5006	if (check_eb_lock_owner(eb: buf)) {
5007	free_extent_buffer(eb: buf);
5008	return ERR_PTR(error: -EUCLEAN);
5009	}
5010
5011	/*
5012	* The reloc trees are just snapshots, so we need them to appear to be
5013	* just like any other fs tree WRT lockdep.
5014	*
5015	* The exception however is in replace_path() in relocation, where we
5016	* hold the lock on the original fs root and then search for the reloc
5017	* root. At that point we need to make sure any reloc root buffers are
5018	* set to the BTRFS_TREE_RELOC_OBJECTID lockdep class in order to make
5019	* lockdep happy.
5020	*/
5021	if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID &&
5022	!test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
5023	lockdep_owner = BTRFS_FS_TREE_OBJECTID;
5024
5025	/* btrfs_clear_buffer_dirty() accesses generation field. */
5026	btrfs_set_header_generation(eb: buf, val: trans->transid);
5027
5028	/*
5029	* This needs to stay, because we could allocate a freed block from an
5030	* old tree into a new tree, so we need to make sure this new block is
5031	* set to the appropriate level and owner.
5032	*/
5033	btrfs_set_buffer_lockdep_class(objectid: lockdep_owner, eb: buf, level);
5034
5035	__btrfs_tree_lock(eb: buf, nest);
5036	btrfs_clear_buffer_dirty(trans, buf);
5037	clear_bit(nr: EXTENT_BUFFER_STALE, addr: &buf->bflags);
5038	clear_bit(nr: EXTENT_BUFFER_NO_CHECK, addr: &buf->bflags);
5039
5040	set_extent_buffer_uptodate(buf);
5041
5042	memzero_extent_buffer(eb: buf, start: 0, len: sizeof(struct btrfs_header));
5043	btrfs_set_header_level(eb: buf, val: level);
5044	btrfs_set_header_bytenr(eb: buf, val: buf->start);
5045	btrfs_set_header_generation(eb: buf, val: trans->transid);
5046	btrfs_set_header_backref_rev(eb: buf, BTRFS_MIXED_BACKREF_REV);
5047	btrfs_set_header_owner(eb: buf, val: owner);
5048	write_extent_buffer_fsid(eb: buf, fsid: fs_info->fs_devices->metadata_uuid);
5049	write_extent_buffer_chunk_tree_uuid(eb: buf, chunk_tree_uuid: fs_info->chunk_tree_uuid);
5050	if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5051	buf->log_index = root->log_transid % 2;
5052	/*
5053	* we allow two log transactions at a time, use different
5054	* EXTENT bit to differentiate dirty pages.
5055	*/
5056	if (buf->log_index == 0)
5057	set_extent_bit(tree: &root->dirty_log_pages, start: buf->start,
5058	end: buf->start + buf->len - 1,
5059	bits: EXTENT_DIRTY, NULL);
5060	else
5061	set_extent_bit(tree: &root->dirty_log_pages, start: buf->start,
5062	end: buf->start + buf->len - 1,
5063	bits: EXTENT_NEW, NULL);
5064	} else {
5065	buf->log_index = -1;
5066	set_extent_bit(tree: &trans->transaction->dirty_pages, start: buf->start,
5067	end: buf->start + buf->len - 1, bits: EXTENT_DIRTY, NULL);
5068	}
5069	/* this returns a buffer locked for blocking */
5070	return buf;
5071	}
5072
5073	/*
5074	* finds a free extent and does all the dirty work required for allocation
5075	* returns the tree buffer or an ERR_PTR on error.
5076	*/
5077	struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
5078	struct btrfs_root *root,
5079	u64 parent, u64 root_objectid,
5080	const struct btrfs_disk_key *key,
5081	int level, u64 hint,
5082	u64 empty_size,
5083	u64 reloc_src_root,
5084	enum btrfs_lock_nesting nest)
5085	{
5086	struct btrfs_fs_info *fs_info = root->fs_info;
5087	struct btrfs_key ins;
5088	struct btrfs_block_rsv *block_rsv;
5089	struct extent_buffer *buf;
5090	struct btrfs_delayed_extent_op *extent_op;
5091	struct btrfs_ref generic_ref = { 0 };
5092	u64 flags = 0;
5093	int ret;
5094	u32 blocksize = fs_info->nodesize;
5095	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
5096	u64 owning_root;
5097
5098	#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5099	if (btrfs_is_testing(fs_info)) {
5100	buf = btrfs_init_new_buffer(trans, root, bytenr: root->alloc_bytenr,
5101	level, owner: root_objectid, nest);
5102	if (!IS_ERR(ptr: buf))
5103	root->alloc_bytenr += blocksize;
5104	return buf;
5105	}
5106	#endif
5107
5108	block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
5109	if (IS_ERR(ptr: block_rsv))
5110	return ERR_CAST(ptr: block_rsv);
5111
5112	ret = btrfs_reserve_extent(root, ram_bytes: blocksize, num_bytes: blocksize, min_alloc_size: blocksize,
5113	empty_size, hint_byte: hint, ins: &ins, is_data: 0, delalloc: 0);
5114	if (ret)
5115	goto out_unuse;
5116
5117	buf = btrfs_init_new_buffer(trans, root, bytenr: ins.objectid, level,
5118	owner: root_objectid, nest);
5119	if (IS_ERR(ptr: buf)) {
5120	ret = PTR_ERR(ptr: buf);
5121	goto out_free_reserved;
5122	}
5123	owning_root = btrfs_header_owner(eb: buf);
5124
5125	if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
5126	if (parent == 0)
5127	parent = ins.objectid;
5128	flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
5129	owning_root = reloc_src_root;
5130	} else
5131	BUG_ON(parent > 0);
5132
5133	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
5134	extent_op = btrfs_alloc_delayed_extent_op();
5135	if (!extent_op) {
5136	ret = -ENOMEM;
5137	goto out_free_buf;
5138	}
5139	if (key)
5140	memcpy(&extent_op->key, key, sizeof(extent_op->key));
5141	else
5142	memset(&extent_op->key, 0, sizeof(extent_op->key));
5143	extent_op->flags_to_set = flags;
5144	extent_op->update_key = skinny_metadata ? false : true;
5145	extent_op->update_flags = true;
5146	extent_op->level = level;
5147
5148	btrfs_init_generic_ref(generic_ref: &generic_ref, action: BTRFS_ADD_DELAYED_EXTENT,
5149	bytenr: ins.objectid, len: ins.offset, parent, owning_root);
5150	btrfs_init_tree_ref(generic_ref: &generic_ref, level, root: root_objectid,
5151	mod_root: root->root_key.objectid, skip_qgroup: false);
5152	btrfs_ref_tree_mod(fs_info, generic_ref: &generic_ref);
5153	ret = btrfs_add_delayed_tree_ref(trans, generic_ref: &generic_ref, extent_op);
5154	if (ret)
5155	goto out_free_delayed;
5156	}
5157	return buf;
5158
5159	out_free_delayed:
5160	btrfs_free_delayed_extent_op(op: extent_op);
5161	out_free_buf:
5162	btrfs_tree_unlock(eb: buf);
5163	free_extent_buffer(eb: buf);
5164	out_free_reserved:
5165	btrfs_free_reserved_extent(fs_info, start: ins.objectid, len: ins.offset, delalloc: 0);
5166	out_unuse:
5167	btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
5168	return ERR_PTR(error: ret);
5169	}
5170
5171	struct walk_control {
5172	u64 refs[BTRFS_MAX_LEVEL];
5173	u64 flags[BTRFS_MAX_LEVEL];
5174	struct btrfs_key update_progress;
5175	struct btrfs_key drop_progress;
5176	int drop_level;
5177	int stage;
5178	int level;
5179	int shared_level;
5180	int update_ref;
5181	int keep_locks;
5182	int reada_slot;
5183	int reada_count;
5184	int restarted;
5185	};
5186
5187	#define DROP_REFERENCE 1
5188	#define UPDATE_BACKREF 2
5189
5190	static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5191	struct btrfs_root *root,
5192	struct walk_control *wc,
5193	struct btrfs_path *path)
5194	{
5195	struct btrfs_fs_info *fs_info = root->fs_info;
5196	u64 bytenr;
5197	u64 generation;
5198	u64 refs;
5199	u64 flags;
5200	u32 nritems;
5201	struct btrfs_key key;
5202	struct extent_buffer *eb;
5203	int ret;
5204	int slot;
5205	int nread = 0;
5206
5207	if (path->slots[wc->level] < wc->reada_slot) {
5208	wc->reada_count = wc->reada_count * 2 / 3;
5209	wc->reada_count = max(wc->reada_count, 2);
5210	} else {
5211	wc->reada_count = wc->reada_count * 3 / 2;
5212	wc->reada_count = min_t(int, wc->reada_count,
5213	BTRFS_NODEPTRS_PER_BLOCK(fs_info));
5214	}
5215
5216	eb = path->nodes[wc->level];
5217	nritems = btrfs_header_nritems(eb);
5218
5219	for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5220	if (nread >= wc->reada_count)
5221	break;
5222
5223	cond_resched();
5224	bytenr = btrfs_node_blockptr(eb, nr: slot);
5225	generation = btrfs_node_ptr_generation(eb, nr: slot);
5226
5227	if (slot == path->slots[wc->level])
5228	goto reada;
5229
5230	if (wc->stage == UPDATE_BACKREF &&
5231	generation <= root->root_key.offset)
5232	continue;
5233
5234	/* We don't lock the tree block, it's OK to be racy here */
5235	ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
5236	offset: wc->level - 1, metadata: 1, refs: &refs,
5237	flags: &flags);
5238	/* We don't care about errors in readahead. */
5239	if (ret < 0)
5240	continue;
5241	BUG_ON(refs == 0);
5242
5243	if (wc->stage == DROP_REFERENCE) {
5244	if (refs == 1)
5245	goto reada;
5246
5247	if (wc->level == 1 &&
5248	(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5249	continue;
5250	if (!wc->update_ref ||
5251	generation <= root->root_key.offset)
5252	continue;
5253	btrfs_node_key_to_cpu(eb, cpu_key: &key, nr: slot);
5254	ret = btrfs_comp_cpu_keys(k1: &key,
5255	k2: &wc->update_progress);
5256	if (ret < 0)
5257	continue;
5258	} else {
5259	if (wc->level == 1 &&
5260	(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5261	continue;
5262	}
5263	reada:
5264	btrfs_readahead_node_child(node: eb, slot);
5265	nread++;
5266	}
5267	wc->reada_slot = slot;
5268	}
5269
5270	/*
5271	* helper to process tree block while walking down the tree.
5272	*
5273	* when wc->stage == UPDATE_BACKREF, this function updates
5274	* back refs for pointers in the block.
5275	*
5276	* NOTE: return value 1 means we should stop walking down.
5277	*/
5278	static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5279	struct btrfs_root *root,
5280	struct btrfs_path *path,
5281	struct walk_control *wc, int lookup_info)
5282	{
5283	struct btrfs_fs_info *fs_info = root->fs_info;
5284	int level = wc->level;
5285	struct extent_buffer *eb = path->nodes[level];
5286	u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5287	int ret;
5288
5289	if (wc->stage == UPDATE_BACKREF &&
5290	btrfs_header_owner(eb) != root->root_key.objectid)
5291	return 1;
5292
5293	/*
5294	* when reference count of tree block is 1, it won't increase
5295	* again. once full backref flag is set, we never clear it.
5296	*/
5297	if (lookup_info &&
5298	((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5299	(wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5300	BUG_ON(!path->locks[level]);
5301	ret = btrfs_lookup_extent_info(trans, fs_info,
5302	bytenr: eb->start, offset: level, metadata: 1,
5303	refs: &wc->refs[level],
5304	flags: &wc->flags[level]);
5305	BUG_ON(ret == -ENOMEM);
5306	if (ret)
5307	return ret;
5308	BUG_ON(wc->refs[level] == 0);
5309	}
5310
5311	if (wc->stage == DROP_REFERENCE) {
5312	if (wc->refs[level] > 1)
5313	return 1;
5314
5315	if (path->locks[level] && !wc->keep_locks) {
5316	btrfs_tree_unlock_rw(eb, rw: path->locks[level]);
5317	path->locks[level] = 0;
5318	}
5319	return 0;
5320	}
5321
5322	/* wc->stage == UPDATE_BACKREF */
5323	if (!(wc->flags[level] & flag)) {
5324	BUG_ON(!path->locks[level]);
5325	ret = btrfs_inc_ref(trans, root, buf: eb, full_backref: 1);
5326	BUG_ON(ret); /* -ENOMEM */
5327	ret = btrfs_dec_ref(trans, root, buf: eb, full_backref: 0);
5328	BUG_ON(ret); /* -ENOMEM */
5329	ret = btrfs_set_disk_extent_flags(trans, eb, flags: flag);
5330	BUG_ON(ret); /* -ENOMEM */
5331	wc->flags[level] |= flag;
5332	}
5333
5334	/*
5335	* the block is shared by multiple trees, so it's not good to
5336	* keep the tree lock
5337	*/
5338	if (path->locks[level] && level > 0) {
5339	btrfs_tree_unlock_rw(eb, rw: path->locks[level]);
5340	path->locks[level] = 0;
5341	}
5342	return 0;
5343	}
5344
5345	/*
5346	* This is used to verify a ref exists for this root to deal with a bug where we
5347	* would have a drop_progress key that hadn't been updated properly.
5348	*/
5349	static int check_ref_exists(struct btrfs_trans_handle *trans,
5350	struct btrfs_root *root, u64 bytenr, u64 parent,
5351	int level)
5352	{
5353	struct btrfs_path *path;
5354	struct btrfs_extent_inline_ref *iref;
5355	int ret;
5356
5357	path = btrfs_alloc_path();
5358	if (!path)
5359	return -ENOMEM;
5360
5361	ret = lookup_extent_backref(trans, path, ref_ret: &iref, bytenr,
5362	num_bytes: root->fs_info->nodesize, parent,
5363	root_objectid: root->root_key.objectid, owner: level, offset: 0);
5364	btrfs_free_path(p: path);
5365	if (ret == -ENOENT)
5366	return 0;
5367	if (ret < 0)
5368	return ret;
5369	return 1;
5370	}
5371
5372	/*
5373	* helper to process tree block pointer.
5374	*
5375	* when wc->stage == DROP_REFERENCE, this function checks
5376	* reference count of the block pointed to. if the block
5377	* is shared and we need update back refs for the subtree
5378	* rooted at the block, this function changes wc->stage to
5379	* UPDATE_BACKREF. if the block is shared and there is no
5380	* need to update back, this function drops the reference
5381	* to the block.
5382	*
5383	* NOTE: return value 1 means we should stop walking down.
5384	*/
5385	static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5386	struct btrfs_root *root,
5387	struct btrfs_path *path,
5388	struct walk_control *wc, int *lookup_info)
5389	{
5390	struct btrfs_fs_info *fs_info = root->fs_info;
5391	u64 bytenr;
5392	u64 generation;
5393	u64 parent;
5394	struct btrfs_tree_parent_check check = { 0 };
5395	struct btrfs_key key;
5396	struct btrfs_ref ref = { 0 };
5397	struct extent_buffer *next;
5398	int level = wc->level;
5399	int reada = 0;
5400	int ret = 0;
5401	bool need_account = false;
5402
5403	generation = btrfs_node_ptr_generation(eb: path->nodes[level],
5404	nr: path->slots[level]);
5405	/*
5406	* if the lower level block was created before the snapshot
5407	* was created, we know there is no need to update back refs
5408	* for the subtree
5409	*/
5410	if (wc->stage == UPDATE_BACKREF &&
5411	generation <= root->root_key.offset) {
5412	*lookup_info = 1;
5413	return 1;
5414	}
5415
5416	bytenr = btrfs_node_blockptr(eb: path->nodes[level], nr: path->slots[level]);
5417
5418	check.level = level - 1;
5419	check.transid = generation;
5420	check.owner_root = root->root_key.objectid;
5421	check.has_first_key = true;
5422	btrfs_node_key_to_cpu(eb: path->nodes[level], cpu_key: &check.first_key,
5423	nr: path->slots[level]);
5424
5425	next = find_extent_buffer(fs_info, start: bytenr);
5426	if (!next) {
5427	next = btrfs_find_create_tree_block(fs_info, bytenr,
5428	owner_root: root->root_key.objectid, level: level - 1);
5429	if (IS_ERR(ptr: next))
5430	return PTR_ERR(ptr: next);
5431	reada = 1;
5432	}
5433	btrfs_tree_lock(eb: next);
5434
5435	ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, offset: level - 1, metadata: 1,
5436	refs: &wc->refs[level - 1],
5437	flags: &wc->flags[level - 1]);
5438	if (ret < 0)
5439	goto out_unlock;
5440
5441	if (unlikely(wc->refs[level - 1] == 0)) {
5442	btrfs_err(fs_info, "Missing references.");
5443	ret = -EIO;
5444	goto out_unlock;
5445	}
5446	*lookup_info = 0;
5447
5448	if (wc->stage == DROP_REFERENCE) {
5449	if (wc->refs[level - 1] > 1) {
5450	need_account = true;
5451	if (level == 1 &&
5452	(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5453	goto skip;
5454
5455	if (!wc->update_ref ||
5456	generation <= root->root_key.offset)
5457	goto skip;
5458
5459	btrfs_node_key_to_cpu(eb: path->nodes[level], cpu_key: &key,
5460	nr: path->slots[level]);
5461	ret = btrfs_comp_cpu_keys(k1: &key, k2: &wc->update_progress);
5462	if (ret < 0)
5463	goto skip;
5464
5465	wc->stage = UPDATE_BACKREF;
5466	wc->shared_level = level - 1;
5467	}
5468	} else {
5469	if (level == 1 &&
5470	(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5471	goto skip;
5472	}
5473
5474	if (!btrfs_buffer_uptodate(buf: next, parent_transid: generation, atomic: 0)) {
5475	btrfs_tree_unlock(eb: next);
5476	free_extent_buffer(eb: next);
5477	next = NULL;
5478	*lookup_info = 1;
5479	}
5480
5481	if (!next) {
5482	if (reada && level == 1)
5483	reada_walk_down(trans, root, wc, path);
5484	next = read_tree_block(fs_info, bytenr, check: &check);
5485	if (IS_ERR(ptr: next)) {
5486	return PTR_ERR(ptr: next);
5487	} else if (!extent_buffer_uptodate(eb: next)) {
5488	free_extent_buffer(eb: next);
5489	return -EIO;
5490	}
5491	btrfs_tree_lock(eb: next);
5492	}
5493
5494	level--;
5495	ASSERT(level == btrfs_header_level(next));
5496	if (level != btrfs_header_level(eb: next)) {
5497	btrfs_err(root->fs_info, "mismatched level");
5498	ret = -EIO;
5499	goto out_unlock;
5500	}
5501	path->nodes[level] = next;
5502	path->slots[level] = 0;
5503	path->locks[level] = BTRFS_WRITE_LOCK;
5504	wc->level = level;
5505	if (wc->level == 1)
5506	wc->reada_slot = 0;
5507	return 0;
5508	skip:
5509	wc->refs[level - 1] = 0;
5510	wc->flags[level - 1] = 0;
5511	if (wc->stage == DROP_REFERENCE) {
5512	if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
5513	parent = path->nodes[level]->start;
5514	} else {
5515	ASSERT(root->root_key.objectid ==
5516	btrfs_header_owner(path->nodes[level]));
5517	if (root->root_key.objectid !=
5518	btrfs_header_owner(eb: path->nodes[level])) {
5519	btrfs_err(root->fs_info,
5520	"mismatched block owner");
5521	ret = -EIO;
5522	goto out_unlock;
5523	}
5524	parent = 0;
5525	}
5526
5527	/*
5528	* If we had a drop_progress we need to verify the refs are set
5529	* as expected. If we find our ref then we know that from here
5530	* on out everything should be correct, and we can clear the
5531	* ->restarted flag.
5532	*/
5533	if (wc->restarted) {
5534	ret = check_ref_exists(trans, root, bytenr, parent,
5535	level: level - 1);
5536	if (ret < 0)
5537	goto out_unlock;
5538	if (ret == 0)
5539	goto no_delete;
5540	ret = 0;
5541	wc->restarted = 0;
5542	}
5543
5544	/*
5545	* Reloc tree doesn't contribute to qgroup numbers, and we have
5546	* already accounted them at merge time (replace_path),
5547	* thus we could skip expensive subtree trace here.
5548	*/
5549	if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
5550	need_account) {
5551	ret = btrfs_qgroup_trace_subtree(trans, root_eb: next,
5552	root_gen: generation, root_level: level - 1);
5553	if (ret) {
5554	btrfs_err_rl(fs_info,
5555	"Error %d accounting shared subtree. Quota is out of sync, rescan required.",
5556	ret);
5557	}
5558	}
5559
5560	/*
5561	* We need to update the next key in our walk control so we can
5562	* update the drop_progress key accordingly. We don't care if
5563	* find_next_key doesn't find a key because that means we're at
5564	* the end and are going to clean up now.
5565	*/
5566	wc->drop_level = level;
5567	find_next_key(path, level, key: &wc->drop_progress);
5568
5569	btrfs_init_generic_ref(generic_ref: &ref, action: BTRFS_DROP_DELAYED_REF, bytenr,
5570	len: fs_info->nodesize, parent,
5571	owning_root: btrfs_header_owner(eb: next));
5572	btrfs_init_tree_ref(generic_ref: &ref, level: level - 1, root: root->root_key.objectid,
5573	mod_root: 0, skip_qgroup: false);
5574	ret = btrfs_free_extent(trans, ref: &ref);
5575	if (ret)
5576	goto out_unlock;
5577	}
5578	no_delete:
5579	*lookup_info = 1;
5580	ret = 1;
5581
5582	out_unlock:
5583	btrfs_tree_unlock(eb: next);
5584	free_extent_buffer(eb: next);
5585
5586	return ret;
5587	}
5588
5589	/*
5590	* helper to process tree block while walking up the tree.
5591	*
5592	* when wc->stage == DROP_REFERENCE, this function drops
5593	* reference count on the block.
5594	*
5595	* when wc->stage == UPDATE_BACKREF, this function changes
5596	* wc->stage back to DROP_REFERENCE if we changed wc->stage
5597	* to UPDATE_BACKREF previously while processing the block.
5598	*
5599	* NOTE: return value 1 means we should stop walking up.
5600	*/
5601	static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
5602	struct btrfs_root *root,
5603	struct btrfs_path *path,
5604	struct walk_control *wc)
5605	{
5606	struct btrfs_fs_info *fs_info = root->fs_info;
5607	int ret;
5608	int level = wc->level;
5609	struct extent_buffer *eb = path->nodes[level];
5610	u64 parent = 0;
5611
5612	if (wc->stage == UPDATE_BACKREF) {
5613	BUG_ON(wc->shared_level < level);
5614	if (level < wc->shared_level)
5615	goto out;
5616
5617	ret = find_next_key(path, level: level + 1, key: &wc->update_progress);
5618	if (ret > 0)
5619	wc->update_ref = 0;
5620
5621	wc->stage = DROP_REFERENCE;
5622	wc->shared_level = -1;
5623	path->slots[level] = 0;
5624
5625	/*
5626	* check reference count again if the block isn't locked.
5627	* we should start walking down the tree again if reference
5628	* count is one.
5629	*/
5630	if (!path->locks[level]) {
5631	BUG_ON(level == 0);
5632	btrfs_tree_lock(eb);
5633	path->locks[level] = BTRFS_WRITE_LOCK;
5634
5635	ret = btrfs_lookup_extent_info(trans, fs_info,
5636	bytenr: eb->start, offset: level, metadata: 1,
5637	refs: &wc->refs[level],
5638	flags: &wc->flags[level]);
5639	if (ret < 0) {
5640	btrfs_tree_unlock_rw(eb, rw: path->locks[level]);
5641	path->locks[level] = 0;
5642	return ret;
5643	}
5644	BUG_ON(wc->refs[level] == 0);
5645	if (wc->refs[level] == 1) {
5646	btrfs_tree_unlock_rw(eb, rw: path->locks[level]);
5647	path->locks[level] = 0;
5648	return 1;
5649	}
5650	}
5651	}
5652
5653	/* wc->stage == DROP_REFERENCE */
5654	BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5655
5656	if (wc->refs[level] == 1) {
5657	if (level == 0) {
5658	if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5659	ret = btrfs_dec_ref(trans, root, buf: eb, full_backref: 1);
5660	else
5661	ret = btrfs_dec_ref(trans, root, buf: eb, full_backref: 0);
5662	BUG_ON(ret); /* -ENOMEM */
5663	if (is_fstree(rootid: root->root_key.objectid)) {
5664	ret = btrfs_qgroup_trace_leaf_items(trans, eb);
5665	if (ret) {
5666	btrfs_err_rl(fs_info,
5667	"error %d accounting leaf items, quota is out of sync, rescan required",
5668	ret);
5669	}
5670	}
5671	}
5672	/* Make block locked assertion in btrfs_clear_buffer_dirty happy. */
5673	if (!path->locks[level]) {
5674	btrfs_tree_lock(eb);
5675	path->locks[level] = BTRFS_WRITE_LOCK;
5676	}
5677	btrfs_clear_buffer_dirty(trans, buf: eb);
5678	}
5679
5680	if (eb == root->node) {
5681	if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5682	parent = eb->start;
5683	else if (root->root_key.objectid != btrfs_header_owner(eb))
5684	goto owner_mismatch;
5685	} else {
5686	if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5687	parent = path->nodes[level + 1]->start;
5688	else if (root->root_key.objectid !=
5689	btrfs_header_owner(eb: path->nodes[level + 1]))
5690	goto owner_mismatch;
5691	}
5692
5693	btrfs_free_tree_block(trans, root_id: btrfs_root_id(root), buf: eb, parent,
5694	last_ref: wc->refs[level] == 1);
5695	out:
5696	wc->refs[level] = 0;
5697	wc->flags[level] = 0;
5698	return 0;
5699
5700	owner_mismatch:
5701	btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
5702	btrfs_header_owner(eb), root->root_key.objectid);
5703	return -EUCLEAN;
5704	}
5705
5706	static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5707	struct btrfs_root *root,
5708	struct btrfs_path *path,
5709	struct walk_control *wc)
5710	{
5711	int level = wc->level;
5712	int lookup_info = 1;
5713	int ret = 0;
5714
5715	while (level >= 0) {
5716	ret = walk_down_proc(trans, root, path, wc, lookup_info);
5717	if (ret)
5718	break;
5719
5720	if (level == 0)
5721	break;
5722
5723	if (path->slots[level] >=
5724	btrfs_header_nritems(eb: path->nodes[level]))
5725	break;
5726
5727	ret = do_walk_down(trans, root, path, wc, lookup_info: &lookup_info);
5728	if (ret > 0) {
5729	path->slots[level]++;
5730	continue;
5731	} else if (ret < 0)
5732	break;
5733	level = wc->level;
5734	}
5735	return (ret == 1) ? 0 : ret;
5736	}
5737
5738	static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5739	struct btrfs_root *root,
5740	struct btrfs_path *path,
5741	struct walk_control *wc, int max_level)
5742	{
5743	int level = wc->level;
5744	int ret;
5745
5746	path->slots[level] = btrfs_header_nritems(eb: path->nodes[level]);
5747	while (level < max_level && path->nodes[level]) {
5748	wc->level = level;
5749	if (path->slots[level] + 1 <
5750	btrfs_header_nritems(eb: path->nodes[level])) {
5751	path->slots[level]++;
5752	return 0;
5753	} else {
5754	ret = walk_up_proc(trans, root, path, wc);
5755	if (ret > 0)
5756	return 0;
5757	if (ret < 0)
5758	return ret;
5759
5760	if (path->locks[level]) {
5761	btrfs_tree_unlock_rw(eb: path->nodes[level],
5762	rw: path->locks[level]);
5763	path->locks[level] = 0;
5764	}
5765	free_extent_buffer(eb: path->nodes[level]);
5766	path->nodes[level] = NULL;
5767	level++;
5768	}
5769	}
5770	return 1;
5771	}
5772
5773	/*
5774	* drop a subvolume tree.
5775	*
5776	* this function traverses the tree freeing any blocks that only
5777	* referenced by the tree.
5778	*
5779	* when a shared tree block is found. this function decreases its
5780	* reference count by one. if update_ref is true, this function
5781	* also make sure backrefs for the shared block and all lower level
5782	* blocks are properly updated.
5783	*
5784	* If called with for_reloc == 0, may exit early with -EAGAIN
5785	*/
5786	int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
5787	{
5788	const bool is_reloc_root = (root->root_key.objectid ==
5789	BTRFS_TREE_RELOC_OBJECTID);
5790	struct btrfs_fs_info *fs_info = root->fs_info;
5791	struct btrfs_path *path;
5792	struct btrfs_trans_handle *trans;
5793	struct btrfs_root *tree_root = fs_info->tree_root;
5794	struct btrfs_root_item *root_item = &root->root_item;
5795	struct walk_control *wc;
5796	struct btrfs_key key;
5797	int err = 0;
5798	int ret;
5799	int level;
5800	bool root_dropped = false;
5801	bool unfinished_drop = false;
5802
5803	btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
5804
5805	path = btrfs_alloc_path();
5806	if (!path) {
5807	err = -ENOMEM;
5808	goto out;
5809	}
5810
5811	wc = kzalloc(size: sizeof(*wc), GFP_NOFS);
5812	if (!wc) {
5813	btrfs_free_path(p: path);
5814	err = -ENOMEM;
5815	goto out;
5816	}
5817
5818	/*
5819	* Use join to avoid potential EINTR from transaction start. See
5820	* wait_reserve_ticket and the whole reservation callchain.
5821	*/
5822	if (for_reloc)
5823	trans = btrfs_join_transaction(root: tree_root);
5824	else
5825	trans = btrfs_start_transaction(root: tree_root, num_items: 0);
5826	if (IS_ERR(ptr: trans)) {
5827	err = PTR_ERR(ptr: trans);
5828	goto out_free;
5829	}
5830
5831	err = btrfs_run_delayed_items(trans);
5832	if (err)
5833	goto out_end_trans;
5834
5835	/*
5836	* This will help us catch people modifying the fs tree while we're
5837	* dropping it. It is unsafe to mess with the fs tree while it's being
5838	* dropped as we unlock the root node and parent nodes as we walk down
5839	* the tree, assuming nothing will change. If something does change
5840	* then we'll have stale information and drop references to blocks we've
5841	* already dropped.
5842	*/
5843	set_bit(nr: BTRFS_ROOT_DELETING, addr: &root->state);
5844	unfinished_drop = test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
5845
5846	if (btrfs_disk_key_objectid(s: &root_item->drop_progress) == 0) {
5847	level = btrfs_header_level(eb: root->node);
5848	path->nodes[level] = btrfs_lock_root_node(root);
5849	path->slots[level] = 0;
5850	path->locks[level] = BTRFS_WRITE_LOCK;
5851	memset(&wc->update_progress, 0,
5852	sizeof(wc->update_progress));
5853	} else {
5854	btrfs_disk_key_to_cpu(cpu_key: &key, disk_key: &root_item->drop_progress);
5855	memcpy(&wc->update_progress, &key,
5856	sizeof(wc->update_progress));
5857
5858	level = btrfs_root_drop_level(s: root_item);
5859	BUG_ON(level == 0);
5860	path->lowest_level = level;
5861	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
5862	path->lowest_level = 0;
5863	if (ret < 0) {
5864	err = ret;
5865	goto out_end_trans;
5866	}
5867	WARN_ON(ret > 0);
5868
5869	/*
5870	* unlock our path, this is safe because only this
5871	* function is allowed to delete this snapshot
5872	*/
5873	btrfs_unlock_up_safe(path, level: 0);
5874
5875	level = btrfs_header_level(eb: root->node);
5876	while (1) {
5877	btrfs_tree_lock(eb: path->nodes[level]);
5878	path->locks[level] = BTRFS_WRITE_LOCK;
5879
5880	ret = btrfs_lookup_extent_info(trans, fs_info,
5881	bytenr: path->nodes[level]->start,
5882	offset: level, metadata: 1, refs: &wc->refs[level],
5883	flags: &wc->flags[level]);
5884	if (ret < 0) {
5885	err = ret;
5886	goto out_end_trans;
5887	}
5888	BUG_ON(wc->refs[level] == 0);
5889
5890	if (level == btrfs_root_drop_level(s: root_item))
5891	break;
5892
5893	btrfs_tree_unlock(eb: path->nodes[level]);
5894	path->locks[level] = 0;
5895	WARN_ON(wc->refs[level] != 1);
5896	level--;
5897	}
5898	}
5899
5900	wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
5901	wc->level = level;
5902	wc->shared_level = -1;
5903	wc->stage = DROP_REFERENCE;
5904	wc->update_ref = update_ref;
5905	wc->keep_locks = 0;
5906	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(info: fs_info);
5907
5908	while (1) {
5909
5910	ret = walk_down_tree(trans, root, path, wc);
5911	if (ret < 0) {
5912	btrfs_abort_transaction(trans, ret);
5913	err = ret;
5914	break;
5915	}
5916
5917	ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
5918	if (ret < 0) {
5919	btrfs_abort_transaction(trans, ret);
5920	err = ret;
5921	break;
5922	}
5923
5924	if (ret > 0) {
5925	BUG_ON(wc->stage != DROP_REFERENCE);
5926	break;
5927	}
5928
5929	if (wc->stage == DROP_REFERENCE) {
5930	wc->drop_level = wc->level;
5931	btrfs_node_key_to_cpu(eb: path->nodes[wc->drop_level],
5932	cpu_key: &wc->drop_progress,
5933	nr: path->slots[wc->drop_level]);
5934	}
5935	btrfs_cpu_key_to_disk(disk_key: &root_item->drop_progress,
5936	cpu_key: &wc->drop_progress);
5937	btrfs_set_root_drop_level(s: root_item, val: wc->drop_level);
5938
5939	BUG_ON(wc->level == 0);
5940	if (btrfs_should_end_transaction(trans) ||
5941	(!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
5942	ret = btrfs_update_root(trans, root: tree_root,
5943	key: &root->root_key,
5944	item: root_item);
5945	if (ret) {
5946	btrfs_abort_transaction(trans, ret);
5947	err = ret;
5948	goto out_end_trans;
5949	}
5950
5951	if (!is_reloc_root)
5952	btrfs_set_last_root_drop_gen(fs_info, gen: trans->transid);
5953
5954	btrfs_end_transaction_throttle(trans);
5955	if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
5956	btrfs_debug(fs_info,
5957	"drop snapshot early exit");
5958	err = -EAGAIN;
5959	goto out_free;
5960	}
5961
5962	/*
5963	* Use join to avoid potential EINTR from transaction
5964	* start. See wait_reserve_ticket and the whole
5965	* reservation callchain.
5966	*/
5967	if (for_reloc)
5968	trans = btrfs_join_transaction(root: tree_root);
5969	else
5970	trans = btrfs_start_transaction(root: tree_root, num_items: 0);
5971	if (IS_ERR(ptr: trans)) {
5972	err = PTR_ERR(ptr: trans);
5973	goto out_free;
5974	}
5975	}
5976	}
5977	btrfs_release_path(p: path);
5978	if (err)
5979	goto out_end_trans;
5980
5981	ret = btrfs_del_root(trans, key: &root->root_key);
5982	if (ret) {
5983	btrfs_abort_transaction(trans, ret);
5984	err = ret;
5985	goto out_end_trans;
5986	}
5987
5988	if (!is_reloc_root) {
5989	ret = btrfs_find_root(root: tree_root, search_key: &root->root_key, path,
5990	NULL, NULL);
5991	if (ret < 0) {
5992	btrfs_abort_transaction(trans, ret);
5993	err = ret;
5994	goto out_end_trans;
5995	} else if (ret > 0) {
5996	/* if we fail to delete the orphan item this time
5997	* around, it'll get picked up the next time.
5998	*
5999	* The most common failure here is just -ENOENT.
6000	*/
6001	btrfs_del_orphan_item(trans, root: tree_root,
6002	offset: root->root_key.objectid);
6003	}
6004	}
6005
6006	/*
6007	* This subvolume is going to be completely dropped, and won't be
6008	* recorded as dirty roots, thus pertrans meta rsv will not be freed at
6009	* commit transaction time. So free it here manually.
6010	*/
6011	btrfs_qgroup_convert_reserved_meta(root, INT_MAX);
6012	btrfs_qgroup_free_meta_all_pertrans(root);
6013
6014	if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state))
6015	btrfs_add_dropped_root(trans, root);
6016	else
6017	btrfs_put_root(root);
6018	root_dropped = true;
6019	out_end_trans:
6020	if (!is_reloc_root)
6021	btrfs_set_last_root_drop_gen(fs_info, gen: trans->transid);
6022
6023	btrfs_end_transaction_throttle(trans);
6024	out_free:
6025	kfree(objp: wc);
6026	btrfs_free_path(p: path);
6027	out:
6028	/*
6029	* We were an unfinished drop root, check to see if there are any
6030	* pending, and if not clear and wake up any waiters.
6031	*/
6032	if (!err && unfinished_drop)
6033	btrfs_maybe_wake_unfinished_drop(fs_info);
6034
6035	/*
6036	* So if we need to stop dropping the snapshot for whatever reason we
6037	* need to make sure to add it back to the dead root list so that we
6038	* keep trying to do the work later. This also cleans up roots if we
6039	* don't have it in the radix (like when we recover after a power fail
6040	* or unmount) so we don't leak memory.
6041	*/
6042	if (!for_reloc && !root_dropped)
6043	btrfs_add_dead_root(root);
6044	return err;
6045	}
6046
6047	/*
6048	* drop subtree rooted at tree block 'node'.
6049	*
6050	* NOTE: this function will unlock and release tree block 'node'
6051	* only used by relocation code
6052	*/
6053	int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6054	struct btrfs_root *root,
6055	struct extent_buffer *node,
6056	struct extent_buffer *parent)
6057	{
6058	struct btrfs_fs_info *fs_info = root->fs_info;
6059	struct btrfs_path *path;
6060	struct walk_control *wc;
6061	int level;
6062	int parent_level;
6063	int ret = 0;
6064	int wret;
6065
6066	BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6067
6068	path = btrfs_alloc_path();
6069	if (!path)
6070	return -ENOMEM;
6071
6072	wc = kzalloc(size: sizeof(*wc), GFP_NOFS);
6073	if (!wc) {
6074	btrfs_free_path(p: path);
6075	return -ENOMEM;
6076	}
6077
6078	btrfs_assert_tree_write_locked(eb: parent);
6079	parent_level = btrfs_header_level(eb: parent);
6080	atomic_inc(v: &parent->refs);
6081	path->nodes[parent_level] = parent;
6082	path->slots[parent_level] = btrfs_header_nritems(eb: parent);
6083
6084	btrfs_assert_tree_write_locked(eb: node);
6085	level = btrfs_header_level(eb: node);
6086	path->nodes[level] = node;
6087	path->slots[level] = 0;
6088	path->locks[level] = BTRFS_WRITE_LOCK;
6089
6090	wc->refs[parent_level] = 1;
6091	wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6092	wc->level = level;
6093	wc->shared_level = -1;
6094	wc->stage = DROP_REFERENCE;
6095	wc->update_ref = 0;
6096	wc->keep_locks = 1;
6097	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(info: fs_info);
6098
6099	while (1) {
6100	wret = walk_down_tree(trans, root, path, wc);
6101	if (wret < 0) {
6102	ret = wret;
6103	break;
6104	}
6105
6106	wret = walk_up_tree(trans, root, path, wc, max_level: parent_level);
6107	if (wret < 0)
6108	ret = wret;
6109	if (wret != 0)
6110	break;
6111	}
6112
6113	kfree(objp: wc);
6114	btrfs_free_path(p: path);
6115	return ret;
6116	}
6117
6118	int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
6119	u64 start, u64 end)
6120	{
6121	return unpin_extent_range(fs_info, start, end, return_free_space: false);
6122	}
6123
6124	/*
6125	* It used to be that old block groups would be left around forever.
6126	* Iterating over them would be enough to trim unused space. Since we
6127	* now automatically remove them, we also need to iterate over unallocated
6128	* space.
6129	*
6130	* We don't want a transaction for this since the discard may take a
6131	* substantial amount of time. We don't require that a transaction be
6132	* running, but we do need to take a running transaction into account
6133	* to ensure that we're not discarding chunks that were released or
6134	* allocated in the current transaction.
6135	*
6136	* Holding the chunks lock will prevent other threads from allocating
6137	* or releasing chunks, but it won't prevent a running transaction
6138	* from committing and releasing the memory that the pending chunks
6139	* list head uses. For that, we need to take a reference to the
6140	* transaction and hold the commit root sem. We only need to hold
6141	* it while performing the free space search since we have already
6142	* held back allocations.
6143	*/
6144	static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
6145	{
6146	u64 start = BTRFS_DEVICE_RANGE_RESERVED, len = 0, end = 0;
6147	int ret;
6148
6149	*trimmed = 0;
6150
6151	/* Discard not supported = nothing to do. */
6152	if (!bdev_max_discard_sectors(bdev: device->bdev))
6153	return 0;
6154
6155	/* Not writable = nothing to do. */
6156	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
6157	return 0;
6158
6159	/* No free space = nothing to do. */
6160	if (device->total_bytes <= device->bytes_used)
6161	return 0;
6162
6163	ret = 0;
6164
6165	while (1) {
6166	struct btrfs_fs_info *fs_info = device->fs_info;
6167	u64 bytes;
6168
6169	ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
6170	if (ret)
6171	break;
6172
6173	find_first_clear_extent_bit(tree: &device->alloc_state, start,
6174	start_ret: &start, end_ret: &end,
6175	CHUNK_TRIMMED | CHUNK_ALLOCATED);
6176
6177	/* Check if there are any CHUNK_* bits left */
6178	if (start > device->total_bytes) {
6179	WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
6180	btrfs_warn_in_rcu(fs_info,
6181	"ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",
6182	start, end - start + 1,
6183	btrfs_dev_name(device),
6184	device->total_bytes);
6185	mutex_unlock(lock: &fs_info->chunk_mutex);
6186	ret = 0;
6187	break;
6188	}
6189
6190	/* Ensure we skip the reserved space on each device. */
6191	start = max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED);
6192
6193	/*
6194	* If find_first_clear_extent_bit find a range that spans the
6195	* end of the device it will set end to -1, in this case it's up
6196	* to the caller to trim the value to the size of the device.
6197	*/
6198	end = min(end, device->total_bytes - 1);
6199
6200	len = end - start + 1;
6201
6202	/* We didn't find any extents */
6203	if (!len) {
6204	mutex_unlock(lock: &fs_info->chunk_mutex);
6205	ret = 0;
6206	break;
6207	}
6208
6209	ret = btrfs_issue_discard(bdev: device->bdev, start, len,
6210	discarded_bytes: &bytes);
6211	if (!ret)
6212	set_extent_bit(tree: &device->alloc_state, start,
6213	end: start + bytes - 1, CHUNK_TRIMMED, NULL);
6214	mutex_unlock(lock: &fs_info->chunk_mutex);
6215
6216	if (ret)
6217	break;
6218
6219	start += len;
6220	*trimmed += bytes;
6221
6222	if (fatal_signal_pending(current)) {
6223	ret = -ERESTARTSYS;
6224	break;
6225	}
6226
6227	cond_resched();
6228	}
6229
6230	return ret;
6231	}
6232
6233	/*
6234	* Trim the whole filesystem by:
6235	* 1) trimming the free space in each block group
6236	* 2) trimming the unallocated space on each device
6237	*
6238	* This will also continue trimming even if a block group or device encounters
6239	* an error. The return value will be the last error, or 0 if nothing bad
6240	* happens.
6241	*/
6242	int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
6243	{
6244	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6245	struct btrfs_block_group *cache = NULL;
6246	struct btrfs_device *device;
6247	u64 group_trimmed;
6248	u64 range_end = U64_MAX;
6249	u64 start;
6250	u64 end;
6251	u64 trimmed = 0;
6252	u64 bg_failed = 0;
6253	u64 dev_failed = 0;
6254	int bg_ret = 0;
6255	int dev_ret = 0;
6256	int ret = 0;
6257
6258	if (range->start == U64_MAX)
6259	return -EINVAL;
6260
6261	/*
6262	* Check range overflow if range->len is set.
6263	* The default range->len is U64_MAX.
6264	*/
6265	if (range->len != U64_MAX &&
6266	check_add_overflow(range->start, range->len, &range_end))
6267	return -EINVAL;
6268
6269	cache = btrfs_lookup_first_block_group(info: fs_info, bytenr: range->start);
6270	for (; cache; cache = btrfs_next_block_group(cache)) {
6271	if (cache->start >= range_end) {
6272	btrfs_put_block_group(cache);
6273	break;
6274	}
6275
6276	start = max(range->start, cache->start);
6277	end = min(range_end, cache->start + cache->length);
6278
6279	if (end - start >= range->minlen) {
6280	if (!btrfs_block_group_done(cache)) {
6281	ret = btrfs_cache_block_group(cache, wait: true);
6282	if (ret) {
6283	bg_failed++;
6284	bg_ret = ret;
6285	continue;
6286	}
6287	}
6288	ret = btrfs_trim_block_group(block_group: cache,
6289	trimmed: &group_trimmed,
6290	start,
6291	end,
6292	minlen: range->minlen);
6293
6294	trimmed += group_trimmed;
6295	if (ret) {
6296	bg_failed++;
6297	bg_ret = ret;
6298	continue;
6299	}
6300	}
6301	}
6302
6303	if (bg_failed)
6304	btrfs_warn(fs_info,
6305	"failed to trim %llu block group(s), last error %d",
6306	bg_failed, bg_ret);
6307
6308	mutex_lock(&fs_devices->device_list_mutex);
6309	list_for_each_entry(device, &fs_devices->devices, dev_list) {
6310	if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
6311	continue;
6312
6313	ret = btrfs_trim_free_extents(device, trimmed: &group_trimmed);
6314	if (ret) {
6315	dev_failed++;
6316	dev_ret = ret;
6317	break;
6318	}
6319
6320	trimmed += group_trimmed;
6321	}
6322	mutex_unlock(lock: &fs_devices->device_list_mutex);
6323
6324	if (dev_failed)
6325	btrfs_warn(fs_info,
6326	"failed to trim %llu device(s), last error %d",
6327	dev_failed, dev_ret);
6328	range->len = trimmed;
6329	if (bg_ret)
6330	return bg_ret;
6331	return dev_ret;
6332	}
6333