1	// SPDX-License-Identifier: GPL-2.0
2
3	#include "misc.h"
4	#include "ctree.h"
5	#include "space-info.h"
6	#include "sysfs.h"
7	#include "volumes.h"
8	#include "free-space-cache.h"
9	#include "ordered-data.h"
10	#include "transaction.h"
11	#include "block-group.h"
12	#include "fs.h"
13	#include "accessors.h"
14	#include "extent-tree.h"
15
16	/*
17	* HOW DOES SPACE RESERVATION WORK
18	*
19	* If you want to know about delalloc specifically, there is a separate comment
20	* for that with the delalloc code. This comment is about how the whole system
21	* works generally.
22	*
23	* BASIC CONCEPTS
24	*
25	* 1) space_info. This is the ultimate arbiter of how much space we can use.
26	* There's a description of the bytes_ fields with the struct declaration,
27	* refer to that for specifics on each field. Suffice it to say that for
28	* reservations we care about total_bytes - SUM(space_info->bytes_) when
29	* determining if there is space to make an allocation. There is a space_info
30	* for METADATA, SYSTEM, and DATA areas.
31	*
32	* 2) block_rsv's. These are basically buckets for every different type of
33	* metadata reservation we have. You can see the comment in the block_rsv
34	* code on the rules for each type, but generally block_rsv->reserved is how
35	* much space is accounted for in space_info->bytes_may_use.
36	*
37	* 3) btrfs_calc*_size. These are the worst case calculations we used based
38	* on the number of items we will want to modify. We have one for changing
39	* items, and one for inserting new items. Generally we use these helpers to
40	* determine the size of the block reserves, and then use the actual bytes
41	* values to adjust the space_info counters.
42	*
43	* MAKING RESERVATIONS, THE NORMAL CASE
44	*
45	* We call into either btrfs_reserve_data_bytes() or
46	* btrfs_reserve_metadata_bytes(), depending on which we're looking for, with
47	* num_bytes we want to reserve.
48	*
49	* ->reserve
50	* space_info->bytes_may_reserve += num_bytes
51	*
52	* ->extent allocation
53	* Call btrfs_add_reserved_bytes() which does
54	* space_info->bytes_may_reserve -= num_bytes
55	* space_info->bytes_reserved += extent_bytes
56	*
57	* ->insert reference
58	* Call btrfs_update_block_group() which does
59	* space_info->bytes_reserved -= extent_bytes
60	* space_info->bytes_used += extent_bytes
61	*
62	* MAKING RESERVATIONS, FLUSHING NORMALLY (non-priority)
63	*
64	* Assume we are unable to simply make the reservation because we do not have
65	* enough space
66	*
67	* -> __reserve_bytes
68	* create a reserve_ticket with ->bytes set to our reservation, add it to
69	* the tail of space_info->tickets, kick async flush thread
70	*
71	* ->handle_reserve_ticket
72	* wait on ticket->wait for ->bytes to be reduced to 0, or ->error to be set
73	* on the ticket.
74	*
75	* -> btrfs_async_reclaim_metadata_space/btrfs_async_reclaim_data_space
76	* Flushes various things attempting to free up space.
77	*
78	* -> btrfs_try_granting_tickets()
79	* This is called by anything that either subtracts space from
80	* space_info->bytes_may_use, ->bytes_pinned, etc, or adds to the
81	* space_info->total_bytes. This loops through the ->priority_tickets and
82	* then the ->tickets list checking to see if the reservation can be
83	* completed. If it can the space is added to space_info->bytes_may_use and
84	* the ticket is woken up.
85	*
86	* -> ticket wakeup
87	* Check if ->bytes == 0, if it does we got our reservation and we can carry
88	* on, if not return the appropriate error (ENOSPC, but can be EINTR if we
89	* were interrupted.)
90	*
91	* MAKING RESERVATIONS, FLUSHING HIGH PRIORITY
92	*
93	* Same as the above, except we add ourselves to the
94	* space_info->priority_tickets, and we do not use ticket->wait, we simply
95	* call flush_space() ourselves for the states that are safe for us to call
96	* without deadlocking and hope for the best.
97	*
98	* THE FLUSHING STATES
99	*
100	* Generally speaking we will have two cases for each state, a "nice" state
101	* and a "ALL THE THINGS" state. In btrfs we delay a lot of work in order to
102	* reduce the locking over head on the various trees, and even to keep from
103	* doing any work at all in the case of delayed refs. Each of these delayed
104	* things however hold reservations, and so letting them run allows us to
105	* reclaim space so we can make new reservations.
106	*
107	* FLUSH_DELAYED_ITEMS
108	* Every inode has a delayed item to update the inode. Take a simple write
109	* for example, we would update the inode item at write time to update the
110	* mtime, and then again at finish_ordered_io() time in order to update the
111	* isize or bytes. We keep these delayed items to coalesce these operations
112	* into a single operation done on demand. These are an easy way to reclaim
113	* metadata space.
114	*
115	* FLUSH_DELALLOC
116	* Look at the delalloc comment to get an idea of how much space is reserved
117	* for delayed allocation. We can reclaim some of this space simply by
118	* running delalloc, but usually we need to wait for ordered extents to
119	* reclaim the bulk of this space.
120	*
121	* FLUSH_DELAYED_REFS
122	* We have a block reserve for the outstanding delayed refs space, and every
123	* delayed ref operation holds a reservation. Running these is a quick way
124	* to reclaim space, but we want to hold this until the end because COW can
125	* churn a lot and we can avoid making some extent tree modifications if we
126	* are able to delay for as long as possible.
127	*
128	* ALLOC_CHUNK
129	* We will skip this the first time through space reservation, because of
130	* overcommit and we don't want to have a lot of useless metadata space when
131	* our worst case reservations will likely never come true.
132	*
133	* RUN_DELAYED_IPUTS
134	* If we're freeing inodes we're likely freeing checksums, file extent
135	* items, and extent tree items. Loads of space could be freed up by these
136	* operations, however they won't be usable until the transaction commits.
137	*
138	* COMMIT_TRANS
139	* This will commit the transaction. Historically we had a lot of logic
140	* surrounding whether or not we'd commit the transaction, but this waits born
141	* out of a pre-tickets era where we could end up committing the transaction
142	* thousands of times in a row without making progress. Now thanks to our
143	* ticketing system we know if we're not making progress and can error
144	* everybody out after a few commits rather than burning the disk hoping for
145	* a different answer.
146	*
147	* OVERCOMMIT
148	*
149	* Because we hold so many reservations for metadata we will allow you to
150	* reserve more space than is currently free in the currently allocate
151	* metadata space. This only happens with metadata, data does not allow
152	* overcommitting.
153	*
154	* You can see the current logic for when we allow overcommit in
155	* btrfs_can_overcommit(), but it only applies to unallocated space. If there
156	* is no unallocated space to be had, all reservations are kept within the
157	* free space in the allocated metadata chunks.
158	*
159	* Because of overcommitting, you generally want to use the
160	* btrfs_can_overcommit() logic for metadata allocations, as it does the right
161	* thing with or without extra unallocated space.
162	*/
163
164	u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
165	bool may_use_included)
166	{
167	ASSERT(s_info);
168	return s_info->bytes_used + s_info->bytes_reserved +
169	s_info->bytes_pinned + s_info->bytes_readonly +
170	s_info->bytes_zone_unusable +
171	(may_use_included ? s_info->bytes_may_use : 0);
172	}
173
174	/*
175	* after adding space to the filesystem, we need to clear the full flags
176	* on all the space infos.
177	*/
178	void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
179	{
180	struct list_head *head = &info->space_info;
181	struct btrfs_space_info *found;
182
183	list_for_each_entry(found, head, list)
184	found->full = 0;
185	}
186
187	/*
188	* Block groups with more than this value (percents) of unusable space will be
189	* scheduled for background reclaim.
190	*/
191	#define BTRFS_DEFAULT_ZONED_RECLAIM_THRESH (75)
192
193	/*
194	* Calculate chunk size depending on volume type (regular or zoned).
195	*/
196	static u64 calc_chunk_size(const struct btrfs_fs_info *fs_info, u64 flags)
197	{
198	if (btrfs_is_zoned(fs_info))
199	return fs_info->zone_size;
200
201	ASSERT(flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
202
203	if (flags & BTRFS_BLOCK_GROUP_DATA)
204	return BTRFS_MAX_DATA_CHUNK_SIZE;
205	else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
206	return SZ_32M;
207
208	/* Handle BTRFS_BLOCK_GROUP_METADATA */
209	if (fs_info->fs_devices->total_rw_bytes > 50ULL * SZ_1G)
210	return SZ_1G;
211
212	return SZ_256M;
213	}
214
215	/*
216	* Update default chunk size.
217	*/
218	void btrfs_update_space_info_chunk_size(struct btrfs_space_info *space_info,
219	u64 chunk_size)
220	{
221	WRITE_ONCE(space_info->chunk_size, chunk_size);
222	}
223
224	static int create_space_info(struct btrfs_fs_info *info, u64 flags)
225	{
226
227	struct btrfs_space_info *space_info;
228	int i;
229	int ret;
230
231	space_info = kzalloc(size: sizeof(*space_info), GFP_NOFS);
232	if (!space_info)
233	return -ENOMEM;
234
235	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
236	INIT_LIST_HEAD(list: &space_info->block_groups[i]);
237	init_rwsem(&space_info->groups_sem);
238	spin_lock_init(&space_info->lock);
239	space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
240	space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
241	INIT_LIST_HEAD(list: &space_info->ro_bgs);
242	INIT_LIST_HEAD(list: &space_info->tickets);
243	INIT_LIST_HEAD(list: &space_info->priority_tickets);
244	space_info->clamp = 1;
245	btrfs_update_space_info_chunk_size(space_info, chunk_size: calc_chunk_size(fs_info: info, flags));
246
247	if (btrfs_is_zoned(fs_info: info))
248	space_info->bg_reclaim_threshold = BTRFS_DEFAULT_ZONED_RECLAIM_THRESH;
249
250	ret = btrfs_sysfs_add_space_info_type(fs_info: info, space_info);
251	if (ret)
252	return ret;
253
254	list_add(new: &space_info->list, head: &info->space_info);
255	if (flags & BTRFS_BLOCK_GROUP_DATA)
256	info->data_sinfo = space_info;
257
258	return ret;
259	}
260
261	int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
262	{
263	struct btrfs_super_block *disk_super;
264	u64 features;
265	u64 flags;
266	int mixed = 0;
267	int ret;
268
269	disk_super = fs_info->super_copy;
270	if (!btrfs_super_root(s: disk_super))
271	return -EINVAL;
272
273	features = btrfs_super_incompat_flags(s: disk_super);
274	if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
275	mixed = 1;
276
277	flags = BTRFS_BLOCK_GROUP_SYSTEM;
278	ret = create_space_info(info: fs_info, flags);
279	if (ret)
280	goto out;
281
282	if (mixed) {
283	flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
284	ret = create_space_info(info: fs_info, flags);
285	} else {
286	flags = BTRFS_BLOCK_GROUP_METADATA;
287	ret = create_space_info(info: fs_info, flags);
288	if (ret)
289	goto out;
290
291	flags = BTRFS_BLOCK_GROUP_DATA;
292	ret = create_space_info(info: fs_info, flags);
293	}
294	out:
295	return ret;
296	}
297
298	void btrfs_add_bg_to_space_info(struct btrfs_fs_info *info,
299	struct btrfs_block_group *block_group)
300	{
301	struct btrfs_space_info *found;
302	int factor, index;
303
304	factor = btrfs_bg_type_to_factor(flags: block_group->flags);
305
306	found = btrfs_find_space_info(info, flags: block_group->flags);
307	ASSERT(found);
308	spin_lock(lock: &found->lock);
309	found->total_bytes += block_group->length;
310	found->disk_total += block_group->length * factor;
311	found->bytes_used += block_group->used;
312	found->disk_used += block_group->used * factor;
313	found->bytes_readonly += block_group->bytes_super;
314	found->bytes_zone_unusable += block_group->zone_unusable;
315	if (block_group->length > 0)
316	found->full = 0;
317	btrfs_try_granting_tickets(fs_info: info, space_info: found);
318	spin_unlock(lock: &found->lock);
319
320	block_group->space_info = found;
321
322	index = btrfs_bg_flags_to_raid_index(flags: block_group->flags);
323	down_write(sem: &found->groups_sem);
324	list_add_tail(new: &block_group->list, head: &found->block_groups[index]);
325	up_write(sem: &found->groups_sem);
326	}
327
328	struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
329	u64 flags)
330	{
331	struct list_head *head = &info->space_info;
332	struct btrfs_space_info *found;
333
334	flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
335
336	list_for_each_entry(found, head, list) {
337	if (found->flags & flags)
338	return found;
339	}
340	return NULL;
341	}
342
343	static u64 calc_available_free_space(struct btrfs_fs_info *fs_info,
344	struct btrfs_space_info *space_info,
345	enum btrfs_reserve_flush_enum flush)
346	{
347	struct btrfs_space_info *data_sinfo;
348	u64 profile;
349	u64 avail;
350	u64 data_chunk_size;
351	int factor;
352
353	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
354	profile = btrfs_system_alloc_profile(fs_info);
355	else
356	profile = btrfs_metadata_alloc_profile(fs_info);
357
358	avail = atomic64_read(v: &fs_info->free_chunk_space);
359
360	/*
361	* If we have dup, raid1 or raid10 then only half of the free
362	* space is actually usable. For raid56, the space info used
363	* doesn't include the parity drive, so we don't have to
364	* change the math
365	*/
366	factor = btrfs_bg_type_to_factor(flags: profile);
367	avail = div_u64(dividend: avail, divisor: factor);
368	if (avail == 0)
369	return 0;
370
371	/*
372	* Calculate the data_chunk_size, space_info->chunk_size is the
373	* "optimal" chunk size based on the fs size. However when we actually
374	* allocate the chunk we will strip this down further, making it no more
375	* than 10% of the disk or 1G, whichever is smaller.
376	*/
377	data_sinfo = btrfs_find_space_info(info: fs_info, BTRFS_BLOCK_GROUP_DATA);
378	data_chunk_size = min(data_sinfo->chunk_size,
379	mult_perc(fs_info->fs_devices->total_rw_bytes, 10));
380	data_chunk_size = min_t(u64, data_chunk_size, SZ_1G);
381
382	/*
383	* Since data allocations immediately use block groups as part of the
384	* reservation, because we assume that data reservations will == actual
385	* usage, we could potentially overcommit and then immediately have that
386	* available space used by a data allocation, which could put us in a
387	* bind when we get close to filling the file system.
388	*
389	* To handle this simply remove the data_chunk_size from the available
390	* space. If we are relatively empty this won't affect our ability to
391	* overcommit much, and if we're very close to full it'll keep us from
392	* getting into a position where we've given ourselves very little
393	* metadata wiggle room.
394	*/
395	if (avail <= data_chunk_size)
396	return 0;
397	avail -= data_chunk_size;
398
399	/*
400	* If we aren't flushing all things, let us overcommit up to
401	* 1/2th of the space. If we can flush, don't let us overcommit
402	* too much, let it overcommit up to 1/8 of the space.
403	*/
404	if (flush == BTRFS_RESERVE_FLUSH_ALL)
405	avail >>= 3;
406	else
407	avail >>= 1;
408	return avail;
409	}
410
411	int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
412	struct btrfs_space_info *space_info, u64 bytes,
413	enum btrfs_reserve_flush_enum flush)
414	{
415	u64 avail;
416	u64 used;
417
418	/* Don't overcommit when in mixed mode */
419	if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
420	return 0;
421
422	used = btrfs_space_info_used(s_info: space_info, may_use_included: true);
423	avail = calc_available_free_space(fs_info, space_info, flush);
424
425	if (used + bytes < space_info->total_bytes + avail)
426	return 1;
427	return 0;
428	}
429
430	static void remove_ticket(struct btrfs_space_info *space_info,
431	struct reserve_ticket *ticket)
432	{
433	if (!list_empty(head: &ticket->list)) {
434	list_del_init(entry: &ticket->list);
435	ASSERT(space_info->reclaim_size >= ticket->bytes);
436	space_info->reclaim_size -= ticket->bytes;
437	}
438	}
439
440	/*
441	* This is for space we already have accounted in space_info->bytes_may_use, so
442	* basically when we're returning space from block_rsv's.
443	*/
444	void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
445	struct btrfs_space_info *space_info)
446	{
447	struct list_head *head;
448	enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
449
450	lockdep_assert_held(&space_info->lock);
451
452	head = &space_info->priority_tickets;
453	again:
454	while (!list_empty(head)) {
455	struct reserve_ticket *ticket;
456	u64 used = btrfs_space_info_used(s_info: space_info, may_use_included: true);
457
458	ticket = list_first_entry(head, struct reserve_ticket, list);
459
460	/* Check and see if our ticket can be satisfied now. */
461	if ((used + ticket->bytes <= space_info->total_bytes) ||
462	btrfs_can_overcommit(fs_info, space_info, bytes: ticket->bytes,
463	flush)) {
464	btrfs_space_info_update_bytes_may_use(fs_info,
465	sinfo: space_info,
466	bytes: ticket->bytes);
467	remove_ticket(space_info, ticket);
468	ticket->bytes = 0;
469	space_info->tickets_id++;
470	wake_up(&ticket->wait);
471	} else {
472	break;
473	}
474	}
475
476	if (head == &space_info->priority_tickets) {
477	head = &space_info->tickets;
478	flush = BTRFS_RESERVE_FLUSH_ALL;
479	goto again;
480	}
481	}
482
483	#define DUMP_BLOCK_RSV(fs_info, rsv_name) \
484	do { \
485	struct btrfs_block_rsv *__rsv = &(fs_info)->rsv_name; \
486	spin_lock(&__rsv->lock); \
487	btrfs_info(fs_info, #rsv_name ": size %llu reserved %llu", \
488	__rsv->size, __rsv->reserved); \
489	spin_unlock(&__rsv->lock); \
490	} while (0)
491
492	static const char *space_info_flag_to_str(const struct btrfs_space_info *space_info)
493	{
494	switch (space_info->flags) {
495	case BTRFS_BLOCK_GROUP_SYSTEM:
496	return "SYSTEM";
497	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
498	return "DATA+METADATA";
499	case BTRFS_BLOCK_GROUP_DATA:
500	return "DATA";
501	case BTRFS_BLOCK_GROUP_METADATA:
502	return "METADATA";
503	default:
504	return "UNKNOWN";
505	}
506	}
507
508	static void dump_global_block_rsv(struct btrfs_fs_info *fs_info)
509	{
510	DUMP_BLOCK_RSV(fs_info, global_block_rsv);
511	DUMP_BLOCK_RSV(fs_info, trans_block_rsv);
512	DUMP_BLOCK_RSV(fs_info, chunk_block_rsv);
513	DUMP_BLOCK_RSV(fs_info, delayed_block_rsv);
514	DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv);
515	}
516
517	static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
518	struct btrfs_space_info *info)
519	{
520	const char *flag_str = space_info_flag_to_str(space_info: info);
521	lockdep_assert_held(&info->lock);
522
523	/* The free space could be negative in case of overcommit */
524	btrfs_info(fs_info, "space_info %s has %lld free, is %sfull",
525	flag_str,
526	(s64)(info->total_bytes - btrfs_space_info_used(info, true)),
527	info->full ? "" : "not ");
528	btrfs_info(fs_info,
529	"space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu zone_unusable=%llu",
530	info->total_bytes, info->bytes_used, info->bytes_pinned,
531	info->bytes_reserved, info->bytes_may_use,
532	info->bytes_readonly, info->bytes_zone_unusable);
533	}
534
535	void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
536	struct btrfs_space_info *info, u64 bytes,
537	int dump_block_groups)
538	{
539	struct btrfs_block_group *cache;
540	u64 total_avail = 0;
541	int index = 0;
542
543	spin_lock(lock: &info->lock);
544	__btrfs_dump_space_info(fs_info, info);
545	dump_global_block_rsv(fs_info);
546	spin_unlock(lock: &info->lock);
547
548	if (!dump_block_groups)
549	return;
550
551	down_read(sem: &info->groups_sem);
552	again:
553	list_for_each_entry(cache, &info->block_groups[index], list) {
554	u64 avail;
555
556	spin_lock(lock: &cache->lock);
557	avail = cache->length - cache->used - cache->pinned -
558	cache->reserved - cache->delalloc_bytes -
559	cache->bytes_super - cache->zone_unusable;
560	btrfs_info(fs_info,
561	"block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %llu delalloc %llu super %llu zone_unusable (%llu bytes available) %s",
562	cache->start, cache->length, cache->used, cache->pinned,
563	cache->reserved, cache->delalloc_bytes,
564	cache->bytes_super, cache->zone_unusable,
565	avail, cache->ro ? "[readonly]" : "");
566	spin_unlock(lock: &cache->lock);
567	btrfs_dump_free_space(block_group: cache, bytes);
568	total_avail += avail;
569	}
570	if (++index < BTRFS_NR_RAID_TYPES)
571	goto again;
572	up_read(sem: &info->groups_sem);
573
574	btrfs_info(fs_info, "%llu bytes available across all block groups", total_avail);
575	}
576
577	static inline u64 calc_reclaim_items_nr(const struct btrfs_fs_info *fs_info,
578	u64 to_reclaim)
579	{
580	u64 bytes;
581	u64 nr;
582
583	bytes = btrfs_calc_insert_metadata_size(fs_info, num_items: 1);
584	nr = div64_u64(dividend: to_reclaim, divisor: bytes);
585	if (!nr)
586	nr = 1;
587	return nr;
588	}
589
590	#define EXTENT_SIZE_PER_ITEM SZ_256K
591
592	/*
593	* shrink metadata reservation for delalloc
594	*/
595	static void shrink_delalloc(struct btrfs_fs_info *fs_info,
596	struct btrfs_space_info *space_info,
597	u64 to_reclaim, bool wait_ordered,
598	bool for_preempt)
599	{
600	struct btrfs_trans_handle *trans;
601	u64 delalloc_bytes;
602	u64 ordered_bytes;
603	u64 items;
604	long time_left;
605	int loops;
606
607	delalloc_bytes = percpu_counter_sum_positive(fbc: &fs_info->delalloc_bytes);
608	ordered_bytes = percpu_counter_sum_positive(fbc: &fs_info->ordered_bytes);
609	if (delalloc_bytes == 0 && ordered_bytes == 0)
610	return;
611
612	/* Calc the number of the pages we need flush for space reservation */
613	if (to_reclaim == U64_MAX) {
614	items = U64_MAX;
615	} else {
616	/*
617	* to_reclaim is set to however much metadata we need to
618	* reclaim, but reclaiming that much data doesn't really track
619	* exactly. What we really want to do is reclaim full inode's
620	* worth of reservations, however that's not available to us
621	* here. We will take a fraction of the delalloc bytes for our
622	* flushing loops and hope for the best. Delalloc will expand
623	* the amount we write to cover an entire dirty extent, which
624	* will reclaim the metadata reservation for that range. If
625	* it's not enough subsequent flush stages will be more
626	* aggressive.
627	*/
628	to_reclaim = max(to_reclaim, delalloc_bytes >> 3);
629	items = calc_reclaim_items_nr(fs_info, to_reclaim) * 2;
630	}
631
632	trans = current->journal_info;
633
634	/*
635	* If we are doing more ordered than delalloc we need to just wait on
636	* ordered extents, otherwise we'll waste time trying to flush delalloc
637	* that likely won't give us the space back we need.
638	*/
639	if (ordered_bytes > delalloc_bytes && !for_preempt)
640	wait_ordered = true;
641
642	loops = 0;
643	while ((delalloc_bytes || ordered_bytes) && loops < 3) {
644	u64 temp = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT;
645	long nr_pages = min_t(u64, temp, LONG_MAX);
646	int async_pages;
647
648	btrfs_start_delalloc_roots(fs_info, nr: nr_pages, in_reclaim_context: true);
649
650	/*
651	* We need to make sure any outstanding async pages are now
652	* processed before we continue. This is because things like
653	* sync_inode() try to be smart and skip writing if the inode is
654	* marked clean. We don't use filemap_fwrite for flushing
655	* because we want to control how many pages we write out at a
656	* time, thus this is the only safe way to make sure we've
657	* waited for outstanding compressed workers to have started
658	* their jobs and thus have ordered extents set up properly.
659	*
660	* This exists because we do not want to wait for each
661	* individual inode to finish its async work, we simply want to
662	* start the IO on everybody, and then come back here and wait
663	* for all of the async work to catch up. Once we're done with
664	* that we know we'll have ordered extents for everything and we
665	* can decide if we wait for that or not.
666	*
667	* If we choose to replace this in the future, make absolutely
668	* sure that the proper waiting is being done in the async case,
669	* as there have been bugs in that area before.
670	*/
671	async_pages = atomic_read(v: &fs_info->async_delalloc_pages);
672	if (!async_pages)
673	goto skip_async;
674
675	/*
676	* We don't want to wait forever, if we wrote less pages in this
677	* loop than we have outstanding, only wait for that number of
678	* pages, otherwise we can wait for all async pages to finish
679	* before continuing.
680	*/
681	if (async_pages > nr_pages)
682	async_pages -= nr_pages;
683	else
684	async_pages = 0;
685	wait_event(fs_info->async_submit_wait,
686	atomic_read(&fs_info->async_delalloc_pages) <=
687	async_pages);
688	skip_async:
689	loops++;
690	if (wait_ordered && !trans) {
691	btrfs_wait_ordered_roots(fs_info, nr: items, range_start: 0, range_len: (u64)-1);
692	} else {
693	time_left = schedule_timeout_killable(timeout: 1);
694	if (time_left)
695	break;
696	}
697
698	/*
699	* If we are for preemption we just want a one-shot of delalloc
700	* flushing so we can stop flushing if we decide we don't need
701	* to anymore.
702	*/
703	if (for_preempt)
704	break;
705
706	spin_lock(lock: &space_info->lock);
707	if (list_empty(head: &space_info->tickets) &&
708	list_empty(head: &space_info->priority_tickets)) {
709	spin_unlock(lock: &space_info->lock);
710	break;
711	}
712	spin_unlock(lock: &space_info->lock);
713
714	delalloc_bytes = percpu_counter_sum_positive(
715	fbc: &fs_info->delalloc_bytes);
716	ordered_bytes = percpu_counter_sum_positive(
717	fbc: &fs_info->ordered_bytes);
718	}
719	}
720
721	/*
722	* Try to flush some data based on policy set by @state. This is only advisory
723	* and may fail for various reasons. The caller is supposed to examine the
724	* state of @space_info to detect the outcome.
725	*/
726	static void flush_space(struct btrfs_fs_info *fs_info,
727	struct btrfs_space_info *space_info, u64 num_bytes,
728	enum btrfs_flush_state state, bool for_preempt)
729	{
730	struct btrfs_root *root = fs_info->tree_root;
731	struct btrfs_trans_handle *trans;
732	int nr;
733	int ret = 0;
734
735	switch (state) {
736	case FLUSH_DELAYED_ITEMS_NR:
737	case FLUSH_DELAYED_ITEMS:
738	if (state == FLUSH_DELAYED_ITEMS_NR)
739	nr = calc_reclaim_items_nr(fs_info, to_reclaim: num_bytes) * 2;
740	else
741	nr = -1;
742
743	trans = btrfs_join_transaction_nostart(root);
744	if (IS_ERR(ptr: trans)) {
745	ret = PTR_ERR(ptr: trans);
746	if (ret == -ENOENT)
747	ret = 0;
748	break;
749	}
750	ret = btrfs_run_delayed_items_nr(trans, nr);
751	btrfs_end_transaction(trans);
752	break;
753	case FLUSH_DELALLOC:
754	case FLUSH_DELALLOC_WAIT:
755	case FLUSH_DELALLOC_FULL:
756	if (state == FLUSH_DELALLOC_FULL)
757	num_bytes = U64_MAX;
758	shrink_delalloc(fs_info, space_info, to_reclaim: num_bytes,
759	wait_ordered: state != FLUSH_DELALLOC, for_preempt);
760	break;
761	case FLUSH_DELAYED_REFS_NR:
762	case FLUSH_DELAYED_REFS:
763	trans = btrfs_join_transaction_nostart(root);
764	if (IS_ERR(ptr: trans)) {
765	ret = PTR_ERR(ptr: trans);
766	if (ret == -ENOENT)
767	ret = 0;
768	break;
769	}
770	if (state == FLUSH_DELAYED_REFS_NR)
771	btrfs_run_delayed_refs(trans, min_bytes: num_bytes);
772	else
773	btrfs_run_delayed_refs(trans, min_bytes: 0);
774	btrfs_end_transaction(trans);
775	break;
776	case ALLOC_CHUNK:
777	case ALLOC_CHUNK_FORCE:
778	trans = btrfs_join_transaction(root);
779	if (IS_ERR(ptr: trans)) {
780	ret = PTR_ERR(ptr: trans);
781	break;
782	}
783	ret = btrfs_chunk_alloc(trans,
784	flags: btrfs_get_alloc_profile(fs_info, orig_flags: space_info->flags),
785	force: (state == ALLOC_CHUNK) ? CHUNK_ALLOC_NO_FORCE :
786	CHUNK_ALLOC_FORCE);
787	btrfs_end_transaction(trans);
788
789	if (ret > 0 || ret == -ENOSPC)
790	ret = 0;
791	break;
792	case RUN_DELAYED_IPUTS:
793	/*
794	* If we have pending delayed iputs then we could free up a
795	* bunch of pinned space, so make sure we run the iputs before
796	* we do our pinned bytes check below.
797	*/
798	btrfs_run_delayed_iputs(fs_info);
799	btrfs_wait_on_delayed_iputs(fs_info);
800	break;
801	case COMMIT_TRANS:
802	ASSERT(current->journal_info == NULL);
803	/*
804	* We don't want to start a new transaction, just attach to the
805	* current one or wait it fully commits in case its commit is
806	* happening at the moment. Note: we don't use a nostart join
807	* because that does not wait for a transaction to fully commit
808	* (only for it to be unblocked, state TRANS_STATE_UNBLOCKED).
809	*/
810	trans = btrfs_attach_transaction_barrier(root);
811	if (IS_ERR(ptr: trans)) {
812	ret = PTR_ERR(ptr: trans);
813	if (ret == -ENOENT)
814	ret = 0;
815	break;
816	}
817	ret = btrfs_commit_transaction(trans);
818	break;
819	default:
820	ret = -ENOSPC;
821	break;
822	}
823
824	trace_btrfs_flush_space(fs_info, flags: space_info->flags, num_bytes, state,
825	ret, for_preempt);
826	return;
827	}
828
829	static inline u64
830	btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
831	struct btrfs_space_info *space_info)
832	{
833	u64 used;
834	u64 avail;
835	u64 to_reclaim = space_info->reclaim_size;
836
837	lockdep_assert_held(&space_info->lock);
838
839	avail = calc_available_free_space(fs_info, space_info,
840	flush: BTRFS_RESERVE_FLUSH_ALL);
841	used = btrfs_space_info_used(s_info: space_info, may_use_included: true);
842
843	/*
844	* We may be flushing because suddenly we have less space than we had
845	* before, and now we're well over-committed based on our current free
846	* space. If that's the case add in our overage so we make sure to put
847	* appropriate pressure on the flushing state machine.
848	*/
849	if (space_info->total_bytes + avail < used)
850	to_reclaim += used - (space_info->total_bytes + avail);
851
852	return to_reclaim;
853	}
854
855	static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info,
856	struct btrfs_space_info *space_info)
857	{
858	const u64 global_rsv_size = btrfs_block_rsv_reserved(rsv: &fs_info->global_block_rsv);
859	u64 ordered, delalloc;
860	u64 thresh;
861	u64 used;
862
863	thresh = mult_perc(num: space_info->total_bytes, percent: 90);
864
865	lockdep_assert_held(&space_info->lock);
866
867	/* If we're just plain full then async reclaim just slows us down. */
868	if ((space_info->bytes_used + space_info->bytes_reserved +
869	global_rsv_size) >= thresh)
870	return false;
871
872	used = space_info->bytes_may_use + space_info->bytes_pinned;
873
874	/* The total flushable belongs to the global rsv, don't flush. */
875	if (global_rsv_size >= used)
876	return false;
877
878	/*
879	* 128MiB is 1/4 of the maximum global rsv size. If we have less than
880	* that devoted to other reservations then there's no sense in flushing,
881	* we don't have a lot of things that need flushing.
882	*/
883	if (used - global_rsv_size <= SZ_128M)
884	return false;
885
886	/*
887	* We have tickets queued, bail so we don't compete with the async
888	* flushers.
889	*/
890	if (space_info->reclaim_size)
891	return false;
892
893	/*
894	* If we have over half of the free space occupied by reservations or
895	* pinned then we want to start flushing.
896	*
897	* We do not do the traditional thing here, which is to say
898	*
899	* if (used >= ((total_bytes + avail) / 2))
900	* return 1;
901	*
902	* because this doesn't quite work how we want. If we had more than 50%
903	* of the space_info used by bytes_used and we had 0 available we'd just
904	* constantly run the background flusher. Instead we want it to kick in
905	* if our reclaimable space exceeds our clamped free space.
906	*
907	* Our clamping range is 2^1 -> 2^8. Practically speaking that means
908	* the following:
909	*
910	* Amount of RAM Minimum threshold Maximum threshold
911	*
912	* 256GiB 1GiB 128GiB
913	* 128GiB 512MiB 64GiB
914	* 64GiB 256MiB 32GiB
915	* 32GiB 128MiB 16GiB
916	* 16GiB 64MiB 8GiB
917	*
918	* These are the range our thresholds will fall in, corresponding to how
919	* much delalloc we need for the background flusher to kick in.
920	*/
921
922	thresh = calc_available_free_space(fs_info, space_info,
923	flush: BTRFS_RESERVE_FLUSH_ALL);
924	used = space_info->bytes_used + space_info->bytes_reserved +
925	space_info->bytes_readonly + global_rsv_size;
926	if (used < space_info->total_bytes)
927	thresh += space_info->total_bytes - used;
928	thresh >>= space_info->clamp;
929
930	used = space_info->bytes_pinned;
931
932	/*
933	* If we have more ordered bytes than delalloc bytes then we're either
934	* doing a lot of DIO, or we simply don't have a lot of delalloc waiting
935	* around. Preemptive flushing is only useful in that it can free up
936	* space before tickets need to wait for things to finish. In the case
937	* of ordered extents, preemptively waiting on ordered extents gets us
938	* nothing, if our reservations are tied up in ordered extents we'll
939	* simply have to slow down writers by forcing them to wait on ordered
940	* extents.
941	*
942	* In the case that ordered is larger than delalloc, only include the
943	* block reserves that we would actually be able to directly reclaim
944	* from. In this case if we're heavy on metadata operations this will
945	* clearly be heavy enough to warrant preemptive flushing. In the case
946	* of heavy DIO or ordered reservations, preemptive flushing will just
947	* waste time and cause us to slow down.
948	*
949	* We want to make sure we truly are maxed out on ordered however, so
950	* cut ordered in half, and if it's still higher than delalloc then we
951	* can keep flushing. This is to avoid the case where we start
952	* flushing, and now delalloc == ordered and we stop preemptively
953	* flushing when we could still have several gigs of delalloc to flush.
954	*/
955	ordered = percpu_counter_read_positive(fbc: &fs_info->ordered_bytes) >> 1;
956	delalloc = percpu_counter_read_positive(fbc: &fs_info->delalloc_bytes);
957	if (ordered >= delalloc)
958	used += btrfs_block_rsv_reserved(rsv: &fs_info->delayed_refs_rsv) +
959	btrfs_block_rsv_reserved(rsv: &fs_info->delayed_block_rsv);
960	else
961	used += space_info->bytes_may_use - global_rsv_size;
962
963	return (used >= thresh && !btrfs_fs_closing(fs_info) &&
964	!test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
965	}
966
967	static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info,
968	struct btrfs_space_info *space_info,
969	struct reserve_ticket *ticket)
970	{
971	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
972	u64 min_bytes;
973
974	if (!ticket->steal)
975	return false;
976
977	if (global_rsv->space_info != space_info)
978	return false;
979
980	spin_lock(lock: &global_rsv->lock);
981	min_bytes = mult_perc(num: global_rsv->size, percent: 10);
982	if (global_rsv->reserved < min_bytes + ticket->bytes) {
983	spin_unlock(lock: &global_rsv->lock);
984	return false;
985	}
986	global_rsv->reserved -= ticket->bytes;
987	remove_ticket(space_info, ticket);
988	ticket->bytes = 0;
989	wake_up(&ticket->wait);
990	space_info->tickets_id++;
991	if (global_rsv->reserved < global_rsv->size)
992	global_rsv->full = 0;
993	spin_unlock(lock: &global_rsv->lock);
994
995	return true;
996	}
997
998	/*
999	* We've exhausted our flushing, start failing tickets.
1000	*
1001	* @fs_info - fs_info for this fs
1002	* @space_info - the space info we were flushing
1003	*
1004	* We call this when we've exhausted our flushing ability and haven't made
1005	* progress in satisfying tickets. The reservation code handles tickets in
1006	* order, so if there is a large ticket first and then smaller ones we could
1007	* very well satisfy the smaller tickets. This will attempt to wake up any
1008	* tickets in the list to catch this case.
1009	*
1010	* This function returns true if it was able to make progress by clearing out
1011	* other tickets, or if it stumbles across a ticket that was smaller than the
1012	* first ticket.
1013	*/
1014	static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
1015	struct btrfs_space_info *space_info)
1016	{
1017	struct reserve_ticket *ticket;
1018	u64 tickets_id = space_info->tickets_id;
1019	const bool aborted = BTRFS_FS_ERROR(fs_info);
1020
1021	trace_btrfs_fail_all_tickets(fs_info, sinfo: space_info);
1022
1023	if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1024	btrfs_info(fs_info, "cannot satisfy tickets, dumping space info");
1025	__btrfs_dump_space_info(fs_info, info: space_info);
1026	}
1027
1028	while (!list_empty(head: &space_info->tickets) &&
1029	tickets_id == space_info->tickets_id) {
1030	ticket = list_first_entry(&space_info->tickets,
1031	struct reserve_ticket, list);
1032
1033	if (!aborted && steal_from_global_rsv(fs_info, space_info, ticket))
1034	return true;
1035
1036	if (!aborted && btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1037	btrfs_info(fs_info, "failing ticket with %llu bytes",
1038	ticket->bytes);
1039
1040	remove_ticket(space_info, ticket);
1041	if (aborted)
1042	ticket->error = -EIO;
1043	else
1044	ticket->error = -ENOSPC;
1045	wake_up(&ticket->wait);
1046
1047	/*
1048	* We're just throwing tickets away, so more flushing may not
1049	* trip over btrfs_try_granting_tickets, so we need to call it
1050	* here to see if we can make progress with the next ticket in
1051	* the list.
1052	*/
1053	if (!aborted)
1054	btrfs_try_granting_tickets(fs_info, space_info);
1055	}
1056	return (tickets_id != space_info->tickets_id);
1057	}
1058
1059	/*
1060	* This is for normal flushers, we can wait all goddamned day if we want to. We
1061	* will loop and continuously try to flush as long as we are making progress.
1062	* We count progress as clearing off tickets each time we have to loop.
1063	*/
1064	static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
1065	{
1066	struct btrfs_fs_info *fs_info;
1067	struct btrfs_space_info *space_info;
1068	u64 to_reclaim;
1069	enum btrfs_flush_state flush_state;
1070	int commit_cycles = 0;
1071	u64 last_tickets_id;
1072
1073	fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
1074	space_info = btrfs_find_space_info(info: fs_info, BTRFS_BLOCK_GROUP_METADATA);
1075
1076	spin_lock(lock: &space_info->lock);
1077	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
1078	if (!to_reclaim) {
1079	space_info->flush = 0;
1080	spin_unlock(lock: &space_info->lock);
1081	return;
1082	}
1083	last_tickets_id = space_info->tickets_id;
1084	spin_unlock(lock: &space_info->lock);
1085
1086	flush_state = FLUSH_DELAYED_ITEMS_NR;
1087	do {
1088	flush_space(fs_info, space_info, num_bytes: to_reclaim, state: flush_state, for_preempt: false);
1089	spin_lock(lock: &space_info->lock);
1090	if (list_empty(head: &space_info->tickets)) {
1091	space_info->flush = 0;
1092	spin_unlock(lock: &space_info->lock);
1093	return;
1094	}
1095	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
1096	space_info);
1097	if (last_tickets_id == space_info->tickets_id) {
1098	flush_state++;
1099	} else {
1100	last_tickets_id = space_info->tickets_id;
1101	flush_state = FLUSH_DELAYED_ITEMS_NR;
1102	if (commit_cycles)
1103	commit_cycles--;
1104	}
1105
1106	/*
1107	* We do not want to empty the system of delalloc unless we're
1108	* under heavy pressure, so allow one trip through the flushing
1109	* logic before we start doing a FLUSH_DELALLOC_FULL.
1110	*/
1111	if (flush_state == FLUSH_DELALLOC_FULL && !commit_cycles)
1112	flush_state++;
1113
1114	/*
1115	* We don't want to force a chunk allocation until we've tried
1116	* pretty hard to reclaim space. Think of the case where we
1117	* freed up a bunch of space and so have a lot of pinned space
1118	* to reclaim. We would rather use that than possibly create a
1119	* underutilized metadata chunk. So if this is our first run
1120	* through the flushing state machine skip ALLOC_CHUNK_FORCE and
1121	* commit the transaction. If nothing has changed the next go
1122	* around then we can force a chunk allocation.
1123	*/
1124	if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
1125	flush_state++;
1126
1127	if (flush_state > COMMIT_TRANS) {
1128	commit_cycles++;
1129	if (commit_cycles > 2) {
1130	if (maybe_fail_all_tickets(fs_info, space_info)) {
1131	flush_state = FLUSH_DELAYED_ITEMS_NR;
1132	commit_cycles--;
1133	} else {
1134	space_info->flush = 0;
1135	}
1136	} else {
1137	flush_state = FLUSH_DELAYED_ITEMS_NR;
1138	}
1139	}
1140	spin_unlock(lock: &space_info->lock);
1141	} while (flush_state <= COMMIT_TRANS);
1142	}
1143
1144	/*
1145	* This handles pre-flushing of metadata space before we get to the point that
1146	* we need to start blocking threads on tickets. The logic here is different
1147	* from the other flush paths because it doesn't rely on tickets to tell us how
1148	* much we need to flush, instead it attempts to keep us below the 80% full
1149	* watermark of space by flushing whichever reservation pool is currently the
1150	* largest.
1151	*/
1152	static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
1153	{
1154	struct btrfs_fs_info *fs_info;
1155	struct btrfs_space_info *space_info;
1156	struct btrfs_block_rsv *delayed_block_rsv;
1157	struct btrfs_block_rsv *delayed_refs_rsv;
1158	struct btrfs_block_rsv *global_rsv;
1159	struct btrfs_block_rsv *trans_rsv;
1160	int loops = 0;
1161
1162	fs_info = container_of(work, struct btrfs_fs_info,
1163	preempt_reclaim_work);
1164	space_info = btrfs_find_space_info(info: fs_info, BTRFS_BLOCK_GROUP_METADATA);
1165	delayed_block_rsv = &fs_info->delayed_block_rsv;
1166	delayed_refs_rsv = &fs_info->delayed_refs_rsv;
1167	global_rsv = &fs_info->global_block_rsv;
1168	trans_rsv = &fs_info->trans_block_rsv;
1169
1170	spin_lock(lock: &space_info->lock);
1171	while (need_preemptive_reclaim(fs_info, space_info)) {
1172	enum btrfs_flush_state flush;
1173	u64 delalloc_size = 0;
1174	u64 to_reclaim, block_rsv_size;
1175	const u64 global_rsv_size = btrfs_block_rsv_reserved(rsv: global_rsv);
1176
1177	loops++;
1178
1179	/*
1180	* We don't have a precise counter for the metadata being
1181	* reserved for delalloc, so we'll approximate it by subtracting
1182	* out the block rsv's space from the bytes_may_use. If that
1183	* amount is higher than the individual reserves, then we can
1184	* assume it's tied up in delalloc reservations.
1185	*/
1186	block_rsv_size = global_rsv_size +
1187	btrfs_block_rsv_reserved(rsv: delayed_block_rsv) +
1188	btrfs_block_rsv_reserved(rsv: delayed_refs_rsv) +
1189	btrfs_block_rsv_reserved(rsv: trans_rsv);
1190	if (block_rsv_size < space_info->bytes_may_use)
1191	delalloc_size = space_info->bytes_may_use - block_rsv_size;
1192
1193	/*
1194	* We don't want to include the global_rsv in our calculation,
1195	* because that's space we can't touch. Subtract it from the
1196	* block_rsv_size for the next checks.
1197	*/
1198	block_rsv_size -= global_rsv_size;
1199
1200	/*
1201	* We really want to avoid flushing delalloc too much, as it
1202	* could result in poor allocation patterns, so only flush it if
1203	* it's larger than the rest of the pools combined.
1204	*/
1205	if (delalloc_size > block_rsv_size) {
1206	to_reclaim = delalloc_size;
1207	flush = FLUSH_DELALLOC;
1208	} else if (space_info->bytes_pinned >
1209	(btrfs_block_rsv_reserved(rsv: delayed_block_rsv) +
1210	btrfs_block_rsv_reserved(rsv: delayed_refs_rsv))) {
1211	to_reclaim = space_info->bytes_pinned;
1212	flush = COMMIT_TRANS;
1213	} else if (btrfs_block_rsv_reserved(rsv: delayed_block_rsv) >
1214	btrfs_block_rsv_reserved(rsv: delayed_refs_rsv)) {
1215	to_reclaim = btrfs_block_rsv_reserved(rsv: delayed_block_rsv);
1216	flush = FLUSH_DELAYED_ITEMS_NR;
1217	} else {
1218	to_reclaim = btrfs_block_rsv_reserved(rsv: delayed_refs_rsv);
1219	flush = FLUSH_DELAYED_REFS_NR;
1220	}
1221
1222	spin_unlock(lock: &space_info->lock);
1223
1224	/*
1225	* We don't want to reclaim everything, just a portion, so scale
1226	* down the to_reclaim by 1/4. If it takes us down to 0,
1227	* reclaim 1 items worth.
1228	*/
1229	to_reclaim >>= 2;
1230	if (!to_reclaim)
1231	to_reclaim = btrfs_calc_insert_metadata_size(fs_info, num_items: 1);
1232	flush_space(fs_info, space_info, num_bytes: to_reclaim, state: flush, for_preempt: true);
1233	cond_resched();
1234	spin_lock(lock: &space_info->lock);
1235	}
1236
1237	/* We only went through once, back off our clamping. */
1238	if (loops == 1 && !space_info->reclaim_size)
1239	space_info->clamp = max(1, space_info->clamp - 1);
1240	trace_btrfs_done_preemptive_reclaim(fs_info, sinfo: space_info);
1241	spin_unlock(lock: &space_info->lock);
1242	}
1243
1244	/*
1245	* FLUSH_DELALLOC_WAIT:
1246	* Space is freed from flushing delalloc in one of two ways.
1247	*
1248	* 1) compression is on and we allocate less space than we reserved
1249	* 2) we are overwriting existing space
1250	*
1251	* For #1 that extra space is reclaimed as soon as the delalloc pages are
1252	* COWed, by way of btrfs_add_reserved_bytes() which adds the actual extent
1253	* length to ->bytes_reserved, and subtracts the reserved space from
1254	* ->bytes_may_use.
1255	*
1256	* For #2 this is trickier. Once the ordered extent runs we will drop the
1257	* extent in the range we are overwriting, which creates a delayed ref for
1258	* that freed extent. This however is not reclaimed until the transaction
1259	* commits, thus the next stages.
1260	*
1261	* RUN_DELAYED_IPUTS
1262	* If we are freeing inodes, we want to make sure all delayed iputs have
1263	* completed, because they could have been on an inode with i_nlink == 0, and
1264	* thus have been truncated and freed up space. But again this space is not
1265	* immediately re-usable, it comes in the form of a delayed ref, which must be
1266	* run and then the transaction must be committed.
1267	*
1268	* COMMIT_TRANS
1269	* This is where we reclaim all of the pinned space generated by running the
1270	* iputs
1271	*
1272	* ALLOC_CHUNK_FORCE
1273	* For data we start with alloc chunk force, however we could have been full
1274	* before, and then the transaction commit could have freed new block groups,
1275	* so if we now have space to allocate do the force chunk allocation.
1276	*/
1277	static const enum btrfs_flush_state data_flush_states[] = {
1278	FLUSH_DELALLOC_FULL,
1279	RUN_DELAYED_IPUTS,
1280	COMMIT_TRANS,
1281	ALLOC_CHUNK_FORCE,
1282	};
1283
1284	static void btrfs_async_reclaim_data_space(struct work_struct *work)
1285	{
1286	struct btrfs_fs_info *fs_info;
1287	struct btrfs_space_info *space_info;
1288	u64 last_tickets_id;
1289	enum btrfs_flush_state flush_state = 0;
1290
1291	fs_info = container_of(work, struct btrfs_fs_info, async_data_reclaim_work);
1292	space_info = fs_info->data_sinfo;
1293
1294	spin_lock(lock: &space_info->lock);
1295	if (list_empty(head: &space_info->tickets)) {
1296	space_info->flush = 0;
1297	spin_unlock(lock: &space_info->lock);
1298	return;
1299	}
1300	last_tickets_id = space_info->tickets_id;
1301	spin_unlock(lock: &space_info->lock);
1302
1303	while (!space_info->full) {
1304	flush_space(fs_info, space_info, U64_MAX, state: ALLOC_CHUNK_FORCE, for_preempt: false);
1305	spin_lock(lock: &space_info->lock);
1306	if (list_empty(head: &space_info->tickets)) {
1307	space_info->flush = 0;
1308	spin_unlock(lock: &space_info->lock);
1309	return;
1310	}
1311
1312	/* Something happened, fail everything and bail. */
1313	if (BTRFS_FS_ERROR(fs_info))
1314	goto aborted_fs;
1315	last_tickets_id = space_info->tickets_id;
1316	spin_unlock(lock: &space_info->lock);
1317	}
1318
1319	while (flush_state < ARRAY_SIZE(data_flush_states)) {
1320	flush_space(fs_info, space_info, U64_MAX,
1321	state: data_flush_states[flush_state], for_preempt: false);
1322	spin_lock(lock: &space_info->lock);
1323	if (list_empty(head: &space_info->tickets)) {
1324	space_info->flush = 0;
1325	spin_unlock(lock: &space_info->lock);
1326	return;
1327	}
1328
1329	if (last_tickets_id == space_info->tickets_id) {
1330	flush_state++;
1331	} else {
1332	last_tickets_id = space_info->tickets_id;
1333	flush_state = 0;
1334	}
1335
1336	if (flush_state >= ARRAY_SIZE(data_flush_states)) {
1337	if (space_info->full) {
1338	if (maybe_fail_all_tickets(fs_info, space_info))
1339	flush_state = 0;
1340	else
1341	space_info->flush = 0;
1342	} else {
1343	flush_state = 0;
1344	}
1345
1346	/* Something happened, fail everything and bail. */
1347	if (BTRFS_FS_ERROR(fs_info))
1348	goto aborted_fs;
1349
1350	}
1351	spin_unlock(lock: &space_info->lock);
1352	}
1353	return;
1354
1355	aborted_fs:
1356	maybe_fail_all_tickets(fs_info, space_info);
1357	space_info->flush = 0;
1358	spin_unlock(lock: &space_info->lock);
1359	}
1360
1361	void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info)
1362	{
1363	INIT_WORK(&fs_info->async_reclaim_work, btrfs_async_reclaim_metadata_space);
1364	INIT_WORK(&fs_info->async_data_reclaim_work, btrfs_async_reclaim_data_space);
1365	INIT_WORK(&fs_info->preempt_reclaim_work,
1366	btrfs_preempt_reclaim_metadata_space);
1367	}
1368
1369	static const enum btrfs_flush_state priority_flush_states[] = {
1370	FLUSH_DELAYED_ITEMS_NR,
1371	FLUSH_DELAYED_ITEMS,
1372	ALLOC_CHUNK,
1373	};
1374
1375	static const enum btrfs_flush_state evict_flush_states[] = {
1376	FLUSH_DELAYED_ITEMS_NR,
1377	FLUSH_DELAYED_ITEMS,
1378	FLUSH_DELAYED_REFS_NR,
1379	FLUSH_DELAYED_REFS,
1380	FLUSH_DELALLOC,
1381	FLUSH_DELALLOC_WAIT,
1382	FLUSH_DELALLOC_FULL,
1383	ALLOC_CHUNK,
1384	COMMIT_TRANS,
1385	};
1386
1387	static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
1388	struct btrfs_space_info *space_info,
1389	struct reserve_ticket *ticket,
1390	const enum btrfs_flush_state *states,
1391	int states_nr)
1392	{
1393	u64 to_reclaim;
1394	int flush_state = 0;
1395
1396	spin_lock(lock: &space_info->lock);
1397	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
1398	/*
1399	* This is the priority reclaim path, so to_reclaim could be >0 still
1400	* because we may have only satisfied the priority tickets and still
1401	* left non priority tickets on the list. We would then have
1402	* to_reclaim but ->bytes == 0.
1403	*/
1404	if (ticket->bytes == 0) {
1405	spin_unlock(lock: &space_info->lock);
1406	return;
1407	}
1408
1409	while (flush_state < states_nr) {
1410	spin_unlock(lock: &space_info->lock);
1411	flush_space(fs_info, space_info, num_bytes: to_reclaim, state: states[flush_state],
1412	for_preempt: false);
1413	flush_state++;
1414	spin_lock(lock: &space_info->lock);
1415	if (ticket->bytes == 0) {
1416	spin_unlock(lock: &space_info->lock);
1417	return;
1418	}
1419	}
1420
1421	/*
1422	* Attempt to steal from the global rsv if we can, except if the fs was
1423	* turned into error mode due to a transaction abort when flushing space
1424	* above, in that case fail with the abort error instead of returning
1425	* success to the caller if we can steal from the global rsv - this is
1426	* just to have caller fail immeditelly instead of later when trying to
1427	* modify the fs, making it easier to debug -ENOSPC problems.
1428	*/
1429	if (BTRFS_FS_ERROR(fs_info)) {
1430	ticket->error = BTRFS_FS_ERROR(fs_info);
1431	remove_ticket(space_info, ticket);
1432	} else if (!steal_from_global_rsv(fs_info, space_info, ticket)) {
1433	ticket->error = -ENOSPC;
1434	remove_ticket(space_info, ticket);
1435	}
1436
1437	/*
1438	* We must run try_granting_tickets here because we could be a large
1439	* ticket in front of a smaller ticket that can now be satisfied with
1440	* the available space.
1441	*/
1442	btrfs_try_granting_tickets(fs_info, space_info);
1443	spin_unlock(lock: &space_info->lock);
1444	}
1445
1446	static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info,
1447	struct btrfs_space_info *space_info,
1448	struct reserve_ticket *ticket)
1449	{
1450	spin_lock(lock: &space_info->lock);
1451
1452	/* We could have been granted before we got here. */
1453	if (ticket->bytes == 0) {
1454	spin_unlock(lock: &space_info->lock);
1455	return;
1456	}
1457
1458	while (!space_info->full) {
1459	spin_unlock(lock: &space_info->lock);
1460	flush_space(fs_info, space_info, U64_MAX, state: ALLOC_CHUNK_FORCE, for_preempt: false);
1461	spin_lock(lock: &space_info->lock);
1462	if (ticket->bytes == 0) {
1463	spin_unlock(lock: &space_info->lock);
1464	return;
1465	}
1466	}
1467
1468	ticket->error = -ENOSPC;
1469	remove_ticket(space_info, ticket);
1470	btrfs_try_granting_tickets(fs_info, space_info);
1471	spin_unlock(lock: &space_info->lock);
1472	}
1473
1474	static void wait_reserve_ticket(struct btrfs_fs_info *fs_info,
1475	struct btrfs_space_info *space_info,
1476	struct reserve_ticket *ticket)
1477
1478	{
1479	DEFINE_WAIT(wait);
1480	int ret = 0;
1481
1482	spin_lock(lock: &space_info->lock);
1483	while (ticket->bytes > 0 && ticket->error == 0) {
1484	ret = prepare_to_wait_event(wq_head: &ticket->wait, wq_entry: &wait, TASK_KILLABLE);
1485	if (ret) {
1486	/*
1487	* Delete us from the list. After we unlock the space
1488	* info, we don't want the async reclaim job to reserve
1489	* space for this ticket. If that would happen, then the
1490	* ticket's task would not known that space was reserved
1491	* despite getting an error, resulting in a space leak
1492	* (bytes_may_use counter of our space_info).
1493	*/
1494	remove_ticket(space_info, ticket);
1495	ticket->error = -EINTR;
1496	break;
1497	}
1498	spin_unlock(lock: &space_info->lock);
1499
1500	schedule();
1501
1502	finish_wait(wq_head: &ticket->wait, wq_entry: &wait);
1503	spin_lock(lock: &space_info->lock);
1504	}
1505	spin_unlock(lock: &space_info->lock);
1506	}
1507
1508	/*
1509	* Do the appropriate flushing and waiting for a ticket.
1510	*
1511	* @fs_info: the filesystem
1512	* @space_info: space info for the reservation
1513	* @ticket: ticket for the reservation
1514	* @start_ns: timestamp when the reservation started
1515	* @orig_bytes: amount of bytes originally reserved
1516	* @flush: how much we can flush
1517	*
1518	* This does the work of figuring out how to flush for the ticket, waiting for
1519	* the reservation, and returning the appropriate error if there is one.
1520	*/
1521	static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
1522	struct btrfs_space_info *space_info,
1523	struct reserve_ticket *ticket,
1524	u64 start_ns, u64 orig_bytes,
1525	enum btrfs_reserve_flush_enum flush)
1526	{
1527	int ret;
1528
1529	switch (flush) {
1530	case BTRFS_RESERVE_FLUSH_DATA:
1531	case BTRFS_RESERVE_FLUSH_ALL:
1532	case BTRFS_RESERVE_FLUSH_ALL_STEAL:
1533	wait_reserve_ticket(fs_info, space_info, ticket);
1534	break;
1535	case BTRFS_RESERVE_FLUSH_LIMIT:
1536	priority_reclaim_metadata_space(fs_info, space_info, ticket,
1537	states: priority_flush_states,
1538	ARRAY_SIZE(priority_flush_states));
1539	break;
1540	case BTRFS_RESERVE_FLUSH_EVICT:
1541	priority_reclaim_metadata_space(fs_info, space_info, ticket,
1542	states: evict_flush_states,
1543	ARRAY_SIZE(evict_flush_states));
1544	break;
1545	case BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE:
1546	priority_reclaim_data_space(fs_info, space_info, ticket);
1547	break;
1548	default:
1549	ASSERT(0);
1550	break;
1551	}
1552
1553	ret = ticket->error;
1554	ASSERT(list_empty(&ticket->list));
1555	/*
1556	* Check that we can't have an error set if the reservation succeeded,
1557	* as that would confuse tasks and lead them to error out without
1558	* releasing reserved space (if an error happens the expectation is that
1559	* space wasn't reserved at all).
1560	*/
1561	ASSERT(!(ticket->bytes == 0 && ticket->error));
1562	trace_btrfs_reserve_ticket(fs_info, flags: space_info->flags, bytes: orig_bytes,
1563	start_ns, flush, error: ticket->error);
1564	return ret;
1565	}
1566
1567	/*
1568	* This returns true if this flush state will go through the ordinary flushing
1569	* code.
1570	*/
1571	static inline bool is_normal_flushing(enum btrfs_reserve_flush_enum flush)
1572	{
1573	return (flush == BTRFS_RESERVE_FLUSH_ALL) ||
1574	(flush == BTRFS_RESERVE_FLUSH_ALL_STEAL);
1575	}
1576
1577	static inline void maybe_clamp_preempt(struct btrfs_fs_info *fs_info,
1578	struct btrfs_space_info *space_info)
1579	{
1580	u64 ordered = percpu_counter_sum_positive(fbc: &fs_info->ordered_bytes);
1581	u64 delalloc = percpu_counter_sum_positive(fbc: &fs_info->delalloc_bytes);
1582
1583	/*
1584	* If we're heavy on ordered operations then clamping won't help us. We
1585	* need to clamp specifically to keep up with dirty'ing buffered
1586	* writers, because there's not a 1:1 correlation of writing delalloc
1587	* and freeing space, like there is with flushing delayed refs or
1588	* delayed nodes. If we're already more ordered than delalloc then
1589	* we're keeping up, otherwise we aren't and should probably clamp.
1590	*/
1591	if (ordered < delalloc)
1592	space_info->clamp = min(space_info->clamp + 1, 8);
1593	}
1594
1595	static inline bool can_steal(enum btrfs_reserve_flush_enum flush)
1596	{
1597	return (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL ||
1598	flush == BTRFS_RESERVE_FLUSH_EVICT);
1599	}
1600
1601	/*
1602	* NO_FLUSH and FLUSH_EMERGENCY don't want to create a ticket, they just want to
1603	* fail as quickly as possible.
1604	*/
1605	static inline bool can_ticket(enum btrfs_reserve_flush_enum flush)
1606	{
1607	return (flush != BTRFS_RESERVE_NO_FLUSH &&
1608	flush != BTRFS_RESERVE_FLUSH_EMERGENCY);
1609	}
1610
1611	/*
1612	* Try to reserve bytes from the block_rsv's space.
1613	*
1614	* @fs_info: the filesystem
1615	* @space_info: space info we want to allocate from
1616	* @orig_bytes: number of bytes we want
1617	* @flush: whether or not we can flush to make our reservation
1618	*
1619	* This will reserve orig_bytes number of bytes from the space info associated
1620	* with the block_rsv. If there is not enough space it will make an attempt to
1621	* flush out space to make room. It will do this by flushing delalloc if
1622	* possible or committing the transaction. If flush is 0 then no attempts to
1623	* regain reservations will be made and this will fail if there is not enough
1624	* space already.
1625	*/
1626	static int __reserve_bytes(struct btrfs_fs_info *fs_info,
1627	struct btrfs_space_info *space_info, u64 orig_bytes,
1628	enum btrfs_reserve_flush_enum flush)
1629	{
1630	struct work_struct *async_work;
1631	struct reserve_ticket ticket;
1632	u64 start_ns = 0;
1633	u64 used;
1634	int ret = -ENOSPC;
1635	bool pending_tickets;
1636
1637	ASSERT(orig_bytes);
1638	/*
1639	* If have a transaction handle (current->journal_info != NULL), then
1640	* the flush method can not be neither BTRFS_RESERVE_FLUSH_ALL* nor
1641	* BTRFS_RESERVE_FLUSH_EVICT, as we could deadlock because those
1642	* flushing methods can trigger transaction commits.
1643	*/
1644	if (current->journal_info) {
1645	/* One assert per line for easier debugging. */
1646	ASSERT(flush != BTRFS_RESERVE_FLUSH_ALL);
1647	ASSERT(flush != BTRFS_RESERVE_FLUSH_ALL_STEAL);
1648	ASSERT(flush != BTRFS_RESERVE_FLUSH_EVICT);
1649	}
1650
1651	if (flush == BTRFS_RESERVE_FLUSH_DATA)
1652	async_work = &fs_info->async_data_reclaim_work;
1653	else
1654	async_work = &fs_info->async_reclaim_work;
1655
1656	spin_lock(lock: &space_info->lock);
1657	used = btrfs_space_info_used(s_info: space_info, may_use_included: true);
1658
1659	/*
1660	* We don't want NO_FLUSH allocations to jump everybody, they can
1661	* generally handle ENOSPC in a different way, so treat them the same as
1662	* normal flushers when it comes to skipping pending tickets.
1663	*/
1664	if (is_normal_flushing(flush) || (flush == BTRFS_RESERVE_NO_FLUSH))
1665	pending_tickets = !list_empty(head: &space_info->tickets) ||
1666	!list_empty(head: &space_info->priority_tickets);
1667	else
1668	pending_tickets = !list_empty(head: &space_info->priority_tickets);
1669
1670	/*
1671	* Carry on if we have enough space (short-circuit) OR call
1672	* can_overcommit() to ensure we can overcommit to continue.
1673	*/
1674	if (!pending_tickets &&
1675	((used + orig_bytes <= space_info->total_bytes) ||
1676	btrfs_can_overcommit(fs_info, space_info, bytes: orig_bytes, flush))) {
1677	btrfs_space_info_update_bytes_may_use(fs_info, sinfo: space_info,
1678	bytes: orig_bytes);
1679	ret = 0;
1680	}
1681
1682	/*
1683	* Things are dire, we need to make a reservation so we don't abort. We
1684	* will let this reservation go through as long as we have actual space
1685	* left to allocate for the block.
1686	*/
1687	if (ret && unlikely(flush == BTRFS_RESERVE_FLUSH_EMERGENCY)) {
1688	used = btrfs_space_info_used(s_info: space_info, may_use_included: false);
1689	if (used + orig_bytes <= space_info->total_bytes) {
1690	btrfs_space_info_update_bytes_may_use(fs_info, sinfo: space_info,
1691	bytes: orig_bytes);
1692	ret = 0;
1693	}
1694	}
1695
1696	/*
1697	* If we couldn't make a reservation then setup our reservation ticket
1698	* and kick the async worker if it's not already running.
1699	*
1700	* If we are a priority flusher then we just need to add our ticket to
1701	* the list and we will do our own flushing further down.
1702	*/
1703	if (ret && can_ticket(flush)) {
1704	ticket.bytes = orig_bytes;
1705	ticket.error = 0;
1706	space_info->reclaim_size += ticket.bytes;
1707	init_waitqueue_head(&ticket.wait);
1708	ticket.steal = can_steal(flush);
1709	if (trace_btrfs_reserve_ticket_enabled())
1710	start_ns = ktime_get_ns();
1711
1712	if (flush == BTRFS_RESERVE_FLUSH_ALL ||
1713	flush == BTRFS_RESERVE_FLUSH_ALL_STEAL ||
1714	flush == BTRFS_RESERVE_FLUSH_DATA) {
1715	list_add_tail(new: &ticket.list, head: &space_info->tickets);
1716	if (!space_info->flush) {
1717	/*
1718	* We were forced to add a reserve ticket, so
1719	* our preemptive flushing is unable to keep
1720	* up. Clamp down on the threshold for the
1721	* preemptive flushing in order to keep up with
1722	* the workload.
1723	*/
1724	maybe_clamp_preempt(fs_info, space_info);
1725
1726	space_info->flush = 1;
1727	trace_btrfs_trigger_flush(fs_info,
1728	flags: space_info->flags,
1729	bytes: orig_bytes, flush,
1730	reason: "enospc");
1731	queue_work(wq: system_unbound_wq, work: async_work);
1732	}
1733	} else {
1734	list_add_tail(new: &ticket.list,
1735	head: &space_info->priority_tickets);
1736	}
1737	} else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
1738	/*
1739	* We will do the space reservation dance during log replay,
1740	* which means we won't have fs_info->fs_root set, so don't do
1741	* the async reclaim as we will panic.
1742	*/
1743	if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
1744	!work_busy(work: &fs_info->preempt_reclaim_work) &&
1745	need_preemptive_reclaim(fs_info, space_info)) {
1746	trace_btrfs_trigger_flush(fs_info, flags: space_info->flags,
1747	bytes: orig_bytes, flush, reason: "preempt");
1748	queue_work(wq: system_unbound_wq,
1749	work: &fs_info->preempt_reclaim_work);
1750	}
1751	}
1752	spin_unlock(lock: &space_info->lock);
1753	if (!ret || !can_ticket(flush))
1754	return ret;
1755
1756	return handle_reserve_ticket(fs_info, space_info, ticket: &ticket, start_ns,
1757	orig_bytes, flush);
1758	}
1759
1760	/*
1761	* Try to reserve metadata bytes from the block_rsv's space.
1762	*
1763	* @fs_info: the filesystem
1764	* @space_info: the space_info we're allocating for
1765	* @orig_bytes: number of bytes we want
1766	* @flush: whether or not we can flush to make our reservation
1767	*
1768	* This will reserve orig_bytes number of bytes from the space info associated
1769	* with the block_rsv. If there is not enough space it will make an attempt to
1770	* flush out space to make room. It will do this by flushing delalloc if
1771	* possible or committing the transaction. If flush is 0 then no attempts to
1772	* regain reservations will be made and this will fail if there is not enough
1773	* space already.
1774	*/
1775	int btrfs_reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
1776	struct btrfs_space_info *space_info,
1777	u64 orig_bytes,
1778	enum btrfs_reserve_flush_enum flush)
1779	{
1780	int ret;
1781
1782	ret = __reserve_bytes(fs_info, space_info, orig_bytes, flush);
1783	if (ret == -ENOSPC) {
1784	trace_btrfs_space_reservation(fs_info, type: "space_info:enospc",
1785	val: space_info->flags, bytes: orig_bytes, reserve: 1);
1786
1787	if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1788	btrfs_dump_space_info(fs_info, info: space_info, bytes: orig_bytes, dump_block_groups: 0);
1789	}
1790	return ret;
1791	}
1792
1793	/*
1794	* Try to reserve data bytes for an allocation.
1795	*
1796	* @fs_info: the filesystem
1797	* @bytes: number of bytes we need
1798	* @flush: how we are allowed to flush
1799	*
1800	* This will reserve bytes from the data space info. If there is not enough
1801	* space then we will attempt to flush space as specified by flush.
1802	*/
1803	int btrfs_reserve_data_bytes(struct btrfs_fs_info *fs_info, u64 bytes,
1804	enum btrfs_reserve_flush_enum flush)
1805	{
1806	struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
1807	int ret;
1808
1809	ASSERT(flush == BTRFS_RESERVE_FLUSH_DATA ||
1810	flush == BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE ||
1811	flush == BTRFS_RESERVE_NO_FLUSH);
1812	ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_DATA);
1813
1814	ret = __reserve_bytes(fs_info, space_info: data_sinfo, orig_bytes: bytes, flush);
1815	if (ret == -ENOSPC) {
1816	trace_btrfs_space_reservation(fs_info, type: "space_info:enospc",
1817	val: data_sinfo->flags, bytes, reserve: 1);
1818	if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1819	btrfs_dump_space_info(fs_info, info: data_sinfo, bytes, dump_block_groups: 0);
1820	}
1821	return ret;
1822	}
1823
1824	/* Dump all the space infos when we abort a transaction due to ENOSPC. */
1825	__cold void btrfs_dump_space_info_for_trans_abort(struct btrfs_fs_info *fs_info)
1826	{
1827	struct btrfs_space_info *space_info;
1828
1829	btrfs_info(fs_info, "dumping space info:");
1830	list_for_each_entry(space_info, &fs_info->space_info, list) {
1831	spin_lock(lock: &space_info->lock);
1832	__btrfs_dump_space_info(fs_info, info: space_info);
1833	spin_unlock(lock: &space_info->lock);
1834	}
1835	dump_global_block_rsv(fs_info);
1836	}
1837
1838	/*
1839	* Account the unused space of all the readonly block group in the space_info.
1840	* takes mirrors into account.
1841	*/
1842	u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
1843	{
1844	struct btrfs_block_group *block_group;
1845	u64 free_bytes = 0;
1846	int factor;
1847
1848	/* It's df, we don't care if it's racy */
1849	if (list_empty(head: &sinfo->ro_bgs))
1850	return 0;
1851
1852	spin_lock(lock: &sinfo->lock);
1853	list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
1854	spin_lock(lock: &block_group->lock);
1855
1856	if (!block_group->ro) {
1857	spin_unlock(lock: &block_group->lock);
1858	continue;
1859	}
1860
1861	factor = btrfs_bg_type_to_factor(flags: block_group->flags);
1862	free_bytes += (block_group->length -
1863	block_group->used) * factor;
1864
1865	spin_unlock(lock: &block_group->lock);
1866	}
1867	spin_unlock(lock: &sinfo->lock);
1868
1869	return free_bytes;
1870	}
1871