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1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/jiffies.h>
4#include <linux/kernel.h>
5#include <linux/ktime.h>
6#include <linux/list.h>
7#include <linux/math64.h>
8#include <linux/sizes.h>
9#include <linux/workqueue.h>
10#include "ctree.h"
11#include "block-group.h"
12#include "discard.h"
13#include "free-space-cache.h"
14
15/*
16 * This contains the logic to handle async discard.
17 *
18 * Async discard manages trimming of free space outside of transaction commit.
19 * Discarding is done by managing the block_groups on a LRU list based on free
20 * space recency. Two passes are used to first prioritize discarding extents
21 * and then allow for trimming in the bitmap the best opportunity to coalesce.
22 * The block_groups are maintained on multiple lists to allow for multiple
23 * passes with different discard filter requirements. A delayed work item is
24 * used to manage discarding with timeout determined by a max of the delay
25 * incurred by the iops rate limit, the byte rate limit, and the max delay of
26 * BTRFS_DISCARD_MAX_DELAY.
27 *
28 * Note, this only keeps track of block_groups that are explicitly for data.
29 * Mixed block_groups are not supported.
30 *
31 * The first list is special to manage discarding of fully free block groups.
32 * This is necessary because we issue a final trim for a full free block group
33 * after forgetting it. When a block group becomes unused, instead of directly
34 * being added to the unused_bgs list, we add it to this first list. Then
35 * from there, if it becomes fully discarded, we place it onto the unused_bgs
36 * list.
37 *
38 * The in-memory free space cache serves as the backing state for discard.
39 * Consequently this means there is no persistence. We opt to load all the
40 * block groups in as not discarded, so the mount case degenerates to the
41 * crashing case.
42 *
43 * As the free space cache uses bitmaps, there exists a tradeoff between
44 * ease/efficiency for find_free_extent() and the accuracy of discard state.
45 * Here we opt to let untrimmed regions merge with everything while only letting
46 * trimmed regions merge with other trimmed regions. This can cause
47 * overtrimming, but the coalescing benefit seems to be worth it. Additionally,
48 * bitmap state is tracked as a whole. If we're able to fully trim a bitmap,
49 * the trimmed flag is set on the bitmap. Otherwise, if an allocation comes in,
50 * this resets the state and we will retry trimming the whole bitmap. This is a
51 * tradeoff between discard state accuracy and the cost of accounting.
52 */
53
54/* This is an initial delay to give some chance for block reuse */
55#define BTRFS_DISCARD_DELAY (120ULL * NSEC_PER_SEC)
56#define BTRFS_DISCARD_UNUSED_DELAY (10ULL * NSEC_PER_SEC)
57
58/* Target completion latency of discarding all discardable extents */
59#define BTRFS_DISCARD_TARGET_MSEC (6 * 60 * 60UL * MSEC_PER_SEC)
60#define BTRFS_DISCARD_MIN_DELAY_MSEC (1UL)
61#define BTRFS_DISCARD_MAX_DELAY_MSEC (1000UL)
62#define BTRFS_DISCARD_MAX_IOPS (10U)
63
64/* Montonically decreasing minimum length filters after index 0 */
65static int discard_minlen[BTRFS_NR_DISCARD_LISTS] = {
66 0,
67 BTRFS_ASYNC_DISCARD_MAX_FILTER,
68 BTRFS_ASYNC_DISCARD_MIN_FILTER
69};
70
71static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl,
72 struct btrfs_block_group *block_group)
73{
74 return &discard_ctl->discard_list[block_group->discard_index];
75}
76
77static void __add_to_discard_list(struct btrfs_discard_ctl *discard_ctl,
78 struct btrfs_block_group *block_group)
79{
80 if (!btrfs_run_discard_work(discard_ctl))
81 return;
82
83 if (list_empty(&block_group->discard_list) ||
84 block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED) {
85 if (block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED)
86 block_group->discard_index = BTRFS_DISCARD_INDEX_START;
87 block_group->discard_eligible_time = (ktime_get_ns() +
88 BTRFS_DISCARD_DELAY);
89 block_group->discard_state = BTRFS_DISCARD_RESET_CURSOR;
90 }
91
92 list_move_tail(&block_group->discard_list,
93 get_discard_list(discard_ctl, block_group));
94}
95
96static void add_to_discard_list(struct btrfs_discard_ctl *discard_ctl,
97 struct btrfs_block_group *block_group)
98{
99 if (!btrfs_is_block_group_data_only(block_group))
100 return;
101
102 spin_lock(&discard_ctl->lock);
103 __add_to_discard_list(discard_ctl, block_group);
104 spin_unlock(&discard_ctl->lock);
105}
106
107static void add_to_discard_unused_list(struct btrfs_discard_ctl *discard_ctl,
108 struct btrfs_block_group *block_group)
109{
110 spin_lock(&discard_ctl->lock);
111
112 if (!btrfs_run_discard_work(discard_ctl)) {
113 spin_unlock(&discard_ctl->lock);
114 return;
115 }
116
117 list_del_init(&block_group->discard_list);
118
119 block_group->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
120 block_group->discard_eligible_time = (ktime_get_ns() +
121 BTRFS_DISCARD_UNUSED_DELAY);
122 block_group->discard_state = BTRFS_DISCARD_RESET_CURSOR;
123 list_add_tail(&block_group->discard_list,
124 &discard_ctl->discard_list[BTRFS_DISCARD_INDEX_UNUSED]);
125
126 spin_unlock(&discard_ctl->lock);
127}
128
129static bool remove_from_discard_list(struct btrfs_discard_ctl *discard_ctl,
130 struct btrfs_block_group *block_group)
131{
132 bool running = false;
133
134 spin_lock(&discard_ctl->lock);
135
136 if (block_group == discard_ctl->block_group) {
137 running = true;
138 discard_ctl->block_group = NULL;
139 }
140
141 block_group->discard_eligible_time = 0;
142 list_del_init(&block_group->discard_list);
143
144 spin_unlock(&discard_ctl->lock);
145
146 return running;
147}
148
149/**
150 * find_next_block_group - find block_group that's up next for discarding
151 * @discard_ctl: discard control
152 * @now: current time
153 *
154 * Iterate over the discard lists to find the next block_group up for
155 * discarding checking the discard_eligible_time of block_group.
156 */
157static struct btrfs_block_group *find_next_block_group(
158 struct btrfs_discard_ctl *discard_ctl,
159 u64 now)
160{
161 struct btrfs_block_group *ret_block_group = NULL, *block_group;
162 int i;
163
164 for (i = 0; i < BTRFS_NR_DISCARD_LISTS; i++) {
165 struct list_head *discard_list = &discard_ctl->discard_list[i];
166
167 if (!list_empty(discard_list)) {
168 block_group = list_first_entry(discard_list,
169 struct btrfs_block_group,
170 discard_list);
171
172 if (!ret_block_group)
173 ret_block_group = block_group;
174
175 if (ret_block_group->discard_eligible_time < now)
176 break;
177
178 if (ret_block_group->discard_eligible_time >
179 block_group->discard_eligible_time)
180 ret_block_group = block_group;
181 }
182 }
183
184 return ret_block_group;
185}
186
187/**
188 * peek_discard_list - wrap find_next_block_group()
189 * @discard_ctl: discard control
190 * @discard_state: the discard_state of the block_group after state management
191 * @discard_index: the discard_index of the block_group after state management
192 *
193 * This wraps find_next_block_group() and sets the block_group to be in use.
194 * discard_state's control flow is managed here. Variables related to
195 * discard_state are reset here as needed (eg discard_cursor). @discard_state
196 * and @discard_index are remembered as it may change while we're discarding,
197 * but we want the discard to execute in the context determined here.
198 */
199static struct btrfs_block_group *peek_discard_list(
200 struct btrfs_discard_ctl *discard_ctl,
201 enum btrfs_discard_state *discard_state,
202 int *discard_index)
203{
204 struct btrfs_block_group *block_group;
205 const u64 now = ktime_get_ns();
206
207 spin_lock(&discard_ctl->lock);
208again:
209 block_group = find_next_block_group(discard_ctl, now);
210
211 if (block_group && now > block_group->discard_eligible_time) {
212 if (block_group->discard_index == BTRFS_DISCARD_INDEX_UNUSED &&
213 block_group->used != 0) {
214 if (btrfs_is_block_group_data_only(block_group))
215 __add_to_discard_list(discard_ctl, block_group);
216 else
217 list_del_init(&block_group->discard_list);
218 goto again;
219 }
220 if (block_group->discard_state == BTRFS_DISCARD_RESET_CURSOR) {
221 block_group->discard_cursor = block_group->start;
222 block_group->discard_state = BTRFS_DISCARD_EXTENTS;
223 }
224 discard_ctl->block_group = block_group;
225 *discard_state = block_group->discard_state;
226 *discard_index = block_group->discard_index;
227 } else {
228 block_group = NULL;
229 }
230
231 spin_unlock(&discard_ctl->lock);
232
233 return block_group;
234}
235
236/**
237 * btrfs_discard_check_filter - updates a block groups filters
238 * @block_group: block group of interest
239 * @bytes: recently freed region size after coalescing
240 *
241 * Async discard maintains multiple lists with progressively smaller filters
242 * to prioritize discarding based on size. Should a free space that matches
243 * a larger filter be returned to the free_space_cache, prioritize that discard
244 * by moving @block_group to the proper filter.
245 */
246void btrfs_discard_check_filter(struct btrfs_block_group *block_group,
247 u64 bytes)
248{
249 struct btrfs_discard_ctl *discard_ctl;
250
251 if (!block_group ||
252 !btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
253 return;
254
255 discard_ctl = &block_group->fs_info->discard_ctl;
256
257 if (block_group->discard_index > BTRFS_DISCARD_INDEX_START &&
258 bytes >= discard_minlen[block_group->discard_index - 1]) {
259 int i;
260
261 remove_from_discard_list(discard_ctl, block_group);
262
263 for (i = BTRFS_DISCARD_INDEX_START; i < BTRFS_NR_DISCARD_LISTS;
264 i++) {
265 if (bytes >= discard_minlen[i]) {
266 block_group->discard_index = i;
267 add_to_discard_list(discard_ctl, block_group);
268 break;
269 }
270 }
271 }
272}
273
274/**
275 * btrfs_update_discard_index - moves a block group along the discard lists
276 * @discard_ctl: discard control
277 * @block_group: block_group of interest
278 *
279 * Increment @block_group's discard_index. If it falls of the list, let it be.
280 * Otherwise add it back to the appropriate list.
281 */
282static void btrfs_update_discard_index(struct btrfs_discard_ctl *discard_ctl,
283 struct btrfs_block_group *block_group)
284{
285 block_group->discard_index++;
286 if (block_group->discard_index == BTRFS_NR_DISCARD_LISTS) {
287 block_group->discard_index = 1;
288 return;
289 }
290
291 add_to_discard_list(discard_ctl, block_group);
292}
293
294/**
295 * btrfs_discard_cancel_work - remove a block_group from the discard lists
296 * @discard_ctl: discard control
297 * @block_group: block_group of interest
298 *
299 * This removes @block_group from the discard lists. If necessary, it waits on
300 * the current work and then reschedules the delayed work.
301 */
302void btrfs_discard_cancel_work(struct btrfs_discard_ctl *discard_ctl,
303 struct btrfs_block_group *block_group)
304{
305 if (remove_from_discard_list(discard_ctl, block_group)) {
306 cancel_delayed_work_sync(&discard_ctl->work);
307 btrfs_discard_schedule_work(discard_ctl, true);
308 }
309}
310
311/**
312 * btrfs_discard_queue_work - handles queuing the block_groups
313 * @discard_ctl: discard control
314 * @block_group: block_group of interest
315 *
316 * This maintains the LRU order of the discard lists.
317 */
318void btrfs_discard_queue_work(struct btrfs_discard_ctl *discard_ctl,
319 struct btrfs_block_group *block_group)
320{
321 if (!block_group || !btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
322 return;
323
324 if (block_group->used == 0)
325 add_to_discard_unused_list(discard_ctl, block_group);
326 else
327 add_to_discard_list(discard_ctl, block_group);
328
329 if (!delayed_work_pending(&discard_ctl->work))
330 btrfs_discard_schedule_work(discard_ctl, false);
331}
332
333/**
334 * btrfs_discard_schedule_work - responsible for scheduling the discard work
335 * @discard_ctl: discard control
336 * @override: override the current timer
337 *
338 * Discards are issued by a delayed workqueue item. @override is used to
339 * update the current delay as the baseline delay interval is reevaluated on
340 * transaction commit. This is also maxed with any other rate limit.
341 */
342void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl,
343 bool override)
344{
345 struct btrfs_block_group *block_group;
346 const u64 now = ktime_get_ns();
347
348 spin_lock(&discard_ctl->lock);
349
350 if (!btrfs_run_discard_work(discard_ctl))
351 goto out;
352
353 if (!override && delayed_work_pending(&discard_ctl->work))
354 goto out;
355
356 block_group = find_next_block_group(discard_ctl, now);
357 if (block_group) {
358 unsigned long delay = discard_ctl->delay;
359 u32 kbps_limit = READ_ONCE(discard_ctl->kbps_limit);
360
361 /*
362 * A single delayed workqueue item is responsible for
363 * discarding, so we can manage the bytes rate limit by keeping
364 * track of the previous discard.
365 */
366 if (kbps_limit && discard_ctl->prev_discard) {
367 u64 bps_limit = ((u64)kbps_limit) * SZ_1K;
368 u64 bps_delay = div64_u64(discard_ctl->prev_discard *
369 MSEC_PER_SEC, bps_limit);
370
371 delay = max(delay, msecs_to_jiffies(bps_delay));
372 }
373
374 /*
375 * This timeout is to hopefully prevent immediate discarding
376 * in a recently allocated block group.
377 */
378 if (now < block_group->discard_eligible_time) {
379 u64 bg_timeout = block_group->discard_eligible_time - now;
380
381 delay = max(delay, nsecs_to_jiffies(bg_timeout));
382 }
383
384 mod_delayed_work(discard_ctl->discard_workers,
385 &discard_ctl->work, delay);
386 }
387out:
388 spin_unlock(&discard_ctl->lock);
389}
390
391/**
392 * btrfs_finish_discard_pass - determine next step of a block_group
393 * @discard_ctl: discard control
394 * @block_group: block_group of interest
395 *
396 * This determines the next step for a block group after it's finished going
397 * through a pass on a discard list. If it is unused and fully trimmed, we can
398 * mark it unused and send it to the unused_bgs path. Otherwise, pass it onto
399 * the appropriate filter list or let it fall off.
400 */
401static void btrfs_finish_discard_pass(struct btrfs_discard_ctl *discard_ctl,
402 struct btrfs_block_group *block_group)
403{
404 remove_from_discard_list(discard_ctl, block_group);
405
406 if (block_group->used == 0) {
407 if (btrfs_is_free_space_trimmed(block_group))
408 btrfs_mark_bg_unused(block_group);
409 else
410 add_to_discard_unused_list(discard_ctl, block_group);
411 } else {
412 btrfs_update_discard_index(discard_ctl, block_group);
413 }
414}
415
416/**
417 * btrfs_discard_workfn - discard work function
418 * @work: work
419 *
420 * This finds the next block_group to start discarding and then discards a
421 * single region. It does this in a two-pass fashion: first extents and second
422 * bitmaps. Completely discarded block groups are sent to the unused_bgs path.
423 */
424static void btrfs_discard_workfn(struct work_struct *work)
425{
426 struct btrfs_discard_ctl *discard_ctl;
427 struct btrfs_block_group *block_group;
428 enum btrfs_discard_state discard_state;
429 int discard_index = 0;
430 u64 trimmed = 0;
431 u64 minlen = 0;
432
433 discard_ctl = container_of(work, struct btrfs_discard_ctl, work.work);
434
435 block_group = peek_discard_list(discard_ctl, &discard_state,
436 &discard_index);
437 if (!block_group || !btrfs_run_discard_work(discard_ctl))
438 return;
439
440 /* Perform discarding */
441 minlen = discard_minlen[discard_index];
442
443 if (discard_state == BTRFS_DISCARD_BITMAPS) {
444 u64 maxlen = 0;
445
446 /*
447 * Use the previous levels minimum discard length as the max
448 * length filter. In the case something is added to make a
449 * region go beyond the max filter, the entire bitmap is set
450 * back to BTRFS_TRIM_STATE_UNTRIMMED.
451 */
452 if (discard_index != BTRFS_DISCARD_INDEX_UNUSED)
453 maxlen = discard_minlen[discard_index - 1];
454
455 btrfs_trim_block_group_bitmaps(block_group, &trimmed,
456 block_group->discard_cursor,
457 btrfs_block_group_end(block_group),
458 minlen, maxlen, true);
459 discard_ctl->discard_bitmap_bytes += trimmed;
460 } else {
461 btrfs_trim_block_group_extents(block_group, &trimmed,
462 block_group->discard_cursor,
463 btrfs_block_group_end(block_group),
464 minlen, true);
465 discard_ctl->discard_extent_bytes += trimmed;
466 }
467
468 discard_ctl->prev_discard = trimmed;
469
470 /* Determine next steps for a block_group */
471 if (block_group->discard_cursor >= btrfs_block_group_end(block_group)) {
472 if (discard_state == BTRFS_DISCARD_BITMAPS) {
473 btrfs_finish_discard_pass(discard_ctl, block_group);
474 } else {
475 block_group->discard_cursor = block_group->start;
476 spin_lock(&discard_ctl->lock);
477 if (block_group->discard_state !=
478 BTRFS_DISCARD_RESET_CURSOR)
479 block_group->discard_state =
480 BTRFS_DISCARD_BITMAPS;
481 spin_unlock(&discard_ctl->lock);
482 }
483 }
484
485 spin_lock(&discard_ctl->lock);
486 discard_ctl->block_group = NULL;
487 spin_unlock(&discard_ctl->lock);
488
489 btrfs_discard_schedule_work(discard_ctl, false);
490}
491
492/**
493 * btrfs_run_discard_work - determines if async discard should be running
494 * @discard_ctl: discard control
495 *
496 * Checks if the file system is writeable and BTRFS_FS_DISCARD_RUNNING is set.
497 */
498bool btrfs_run_discard_work(struct btrfs_discard_ctl *discard_ctl)
499{
500 struct btrfs_fs_info *fs_info = container_of(discard_ctl,
501 struct btrfs_fs_info,
502 discard_ctl);
503
504 return (!(fs_info->sb->s_flags & SB_RDONLY) &&
505 test_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags));
506}
507
508/**
509 * btrfs_discard_calc_delay - recalculate the base delay
510 * @discard_ctl: discard control
511 *
512 * Recalculate the base delay which is based off the total number of
513 * discardable_extents. Clamp this between the lower_limit (iops_limit or 1ms)
514 * and the upper_limit (BTRFS_DISCARD_MAX_DELAY_MSEC).
515 */
516void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl)
517{
518 s32 discardable_extents;
519 s64 discardable_bytes;
520 u32 iops_limit;
521 unsigned long delay;
522 unsigned long lower_limit = BTRFS_DISCARD_MIN_DELAY_MSEC;
523
524 discardable_extents = atomic_read(&discard_ctl->discardable_extents);
525 if (!discardable_extents)
526 return;
527
528 spin_lock(&discard_ctl->lock);
529
530 /*
531 * The following is to fix a potential -1 discrepenancy that we're not
532 * sure how to reproduce. But given that this is the only place that
533 * utilizes these numbers and this is only called by from
534 * btrfs_finish_extent_commit() which is synchronized, we can correct
535 * here.
536 */
537 if (discardable_extents < 0)
538 atomic_add(-discardable_extents,
539 &discard_ctl->discardable_extents);
540
541 discardable_bytes = atomic64_read(&discard_ctl->discardable_bytes);
542 if (discardable_bytes < 0)
543 atomic64_add(-discardable_bytes,
544 &discard_ctl->discardable_bytes);
545
546 if (discardable_extents <= 0) {
547 spin_unlock(&discard_ctl->lock);
548 return;
549 }
550
551 iops_limit = READ_ONCE(discard_ctl->iops_limit);
552 if (iops_limit)
553 lower_limit = max_t(unsigned long, lower_limit,
554 MSEC_PER_SEC / iops_limit);
555
556 delay = BTRFS_DISCARD_TARGET_MSEC / discardable_extents;
557 delay = clamp(delay, lower_limit, BTRFS_DISCARD_MAX_DELAY_MSEC);
558 discard_ctl->delay = msecs_to_jiffies(delay);
559
560 spin_unlock(&discard_ctl->lock);
561}
562
563/**
564 * btrfs_discard_update_discardable - propagate discard counters
565 * @block_group: block_group of interest
566 * @ctl: free_space_ctl of @block_group
567 *
568 * This propagates deltas of counters up to the discard_ctl. It maintains a
569 * current counter and a previous counter passing the delta up to the global
570 * stat. Then the current counter value becomes the previous counter value.
571 */
572void btrfs_discard_update_discardable(struct btrfs_block_group *block_group,
573 struct btrfs_free_space_ctl *ctl)
574{
575 struct btrfs_discard_ctl *discard_ctl;
576 s32 extents_delta;
577 s64 bytes_delta;
578
579 if (!block_group ||
580 !btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC) ||
581 !btrfs_is_block_group_data_only(block_group))
582 return;
583
584 discard_ctl = &block_group->fs_info->discard_ctl;
585
586 extents_delta = ctl->discardable_extents[BTRFS_STAT_CURR] -
587 ctl->discardable_extents[BTRFS_STAT_PREV];
588 if (extents_delta) {
589 atomic_add(extents_delta, &discard_ctl->discardable_extents);
590 ctl->discardable_extents[BTRFS_STAT_PREV] =
591 ctl->discardable_extents[BTRFS_STAT_CURR];
592 }
593
594 bytes_delta = ctl->discardable_bytes[BTRFS_STAT_CURR] -
595 ctl->discardable_bytes[BTRFS_STAT_PREV];
596 if (bytes_delta) {
597 atomic64_add(bytes_delta, &discard_ctl->discardable_bytes);
598 ctl->discardable_bytes[BTRFS_STAT_PREV] =
599 ctl->discardable_bytes[BTRFS_STAT_CURR];
600 }
601}
602
603/**
604 * btrfs_discard_punt_unused_bgs_list - punt unused_bgs list to discard lists
605 * @fs_info: fs_info of interest
606 *
607 * The unused_bgs list needs to be punted to the discard lists because the
608 * order of operations is changed. In the normal sychronous discard path, the
609 * block groups are trimmed via a single large trim in transaction commit. This
610 * is ultimately what we are trying to avoid with asynchronous discard. Thus,
611 * it must be done before going down the unused_bgs path.
612 */
613void btrfs_discard_punt_unused_bgs_list(struct btrfs_fs_info *fs_info)
614{
615 struct btrfs_block_group *block_group, *next;
616
617 spin_lock(&fs_info->unused_bgs_lock);
618 /* We enabled async discard, so punt all to the queue */
619 list_for_each_entry_safe(block_group, next, &fs_info->unused_bgs,
620 bg_list) {
621 list_del_init(&block_group->bg_list);
622 btrfs_put_block_group(block_group);
623 btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
624 }
625 spin_unlock(&fs_info->unused_bgs_lock);
626}
627
628/**
629 * btrfs_discard_purge_list - purge discard lists
630 * @discard_ctl: discard control
631 *
632 * If we are disabling async discard, we may have intercepted block groups that
633 * are completely free and ready for the unused_bgs path. As discarding will
634 * now happen in transaction commit or not at all, we can safely mark the
635 * corresponding block groups as unused and they will be sent on their merry
636 * way to the unused_bgs list.
637 */
638static void btrfs_discard_purge_list(struct btrfs_discard_ctl *discard_ctl)
639{
640 struct btrfs_block_group *block_group, *next;
641 int i;
642
643 spin_lock(&discard_ctl->lock);
644 for (i = 0; i < BTRFS_NR_DISCARD_LISTS; i++) {
645 list_for_each_entry_safe(block_group, next,
646 &discard_ctl->discard_list[i],
647 discard_list) {
648 list_del_init(&block_group->discard_list);
649 spin_unlock(&discard_ctl->lock);
650 if (block_group->used == 0)
651 btrfs_mark_bg_unused(block_group);
652 spin_lock(&discard_ctl->lock);
653 }
654 }
655 spin_unlock(&discard_ctl->lock);
656}
657
658void btrfs_discard_resume(struct btrfs_fs_info *fs_info)
659{
660 if (!btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
661 btrfs_discard_cleanup(fs_info);
662 return;
663 }
664
665 btrfs_discard_punt_unused_bgs_list(fs_info);
666
667 set_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags);
668}
669
670void btrfs_discard_stop(struct btrfs_fs_info *fs_info)
671{
672 clear_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags);
673}
674
675void btrfs_discard_init(struct btrfs_fs_info *fs_info)
676{
677 struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
678 int i;
679
680 spin_lock_init(&discard_ctl->lock);
681 INIT_DELAYED_WORK(&discard_ctl->work, btrfs_discard_workfn);
682
683 for (i = 0; i < BTRFS_NR_DISCARD_LISTS; i++)
684 INIT_LIST_HEAD(&discard_ctl->discard_list[i]);
685
686 discard_ctl->prev_discard = 0;
687 atomic_set(&discard_ctl->discardable_extents, 0);
688 atomic64_set(&discard_ctl->discardable_bytes, 0);
689 discard_ctl->max_discard_size = BTRFS_ASYNC_DISCARD_DEFAULT_MAX_SIZE;
690 discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY_MSEC;
691 discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS;
692 discard_ctl->kbps_limit = 0;
693 discard_ctl->discard_extent_bytes = 0;
694 discard_ctl->discard_bitmap_bytes = 0;
695 atomic64_set(&discard_ctl->discard_bytes_saved, 0);
696}
697
698void btrfs_discard_cleanup(struct btrfs_fs_info *fs_info)
699{
700 btrfs_discard_stop(fs_info);
701 cancel_delayed_work_sync(&fs_info->discard_ctl.work);
702 btrfs_discard_purge_list(&fs_info->discard_ctl);
703}