xref: /openbmc/linux/fs/f2fs/gc.c (revision dd21bfa4)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * fs/f2fs/gc.c
4  *
5  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
6  *             http://www.samsung.com/
7  */
8 #include <linux/fs.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/f2fs_fs.h>
12 #include <linux/kthread.h>
13 #include <linux/delay.h>
14 #include <linux/freezer.h>
15 #include <linux/sched/signal.h>
16 #include <linux/random.h>
17 #include <linux/sched/mm.h>
18 
19 #include "f2fs.h"
20 #include "node.h"
21 #include "segment.h"
22 #include "gc.h"
23 #include "iostat.h"
24 #include <trace/events/f2fs.h>
25 
26 static struct kmem_cache *victim_entry_slab;
27 
28 static unsigned int count_bits(const unsigned long *addr,
29 				unsigned int offset, unsigned int len);
30 
31 static int gc_thread_func(void *data)
32 {
33 	struct f2fs_sb_info *sbi = data;
34 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
35 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
36 	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
37 	unsigned int wait_ms;
38 
39 	wait_ms = gc_th->min_sleep_time;
40 
41 	set_freezable();
42 	do {
43 		bool sync_mode, foreground = false;
44 
45 		wait_event_interruptible_timeout(*wq,
46 				kthread_should_stop() || freezing(current) ||
47 				waitqueue_active(fggc_wq) ||
48 				gc_th->gc_wake,
49 				msecs_to_jiffies(wait_ms));
50 
51 		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
52 			foreground = true;
53 
54 		/* give it a try one time */
55 		if (gc_th->gc_wake)
56 			gc_th->gc_wake = 0;
57 
58 		if (try_to_freeze()) {
59 			stat_other_skip_bggc_count(sbi);
60 			continue;
61 		}
62 		if (kthread_should_stop())
63 			break;
64 
65 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
66 			increase_sleep_time(gc_th, &wait_ms);
67 			stat_other_skip_bggc_count(sbi);
68 			continue;
69 		}
70 
71 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
72 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
73 			f2fs_stop_checkpoint(sbi, false);
74 		}
75 
76 		if (!sb_start_write_trylock(sbi->sb)) {
77 			stat_other_skip_bggc_count(sbi);
78 			continue;
79 		}
80 
81 		/*
82 		 * [GC triggering condition]
83 		 * 0. GC is not conducted currently.
84 		 * 1. There are enough dirty segments.
85 		 * 2. IO subsystem is idle by checking the # of writeback pages.
86 		 * 3. IO subsystem is idle by checking the # of requests in
87 		 *    bdev's request list.
88 		 *
89 		 * Note) We have to avoid triggering GCs frequently.
90 		 * Because it is possible that some segments can be
91 		 * invalidated soon after by user update or deletion.
92 		 * So, I'd like to wait some time to collect dirty segments.
93 		 */
94 		if (sbi->gc_mode == GC_URGENT_HIGH) {
95 			spin_lock(&sbi->gc_urgent_high_lock);
96 			if (sbi->gc_urgent_high_limited) {
97 				if (!sbi->gc_urgent_high_remaining) {
98 					sbi->gc_urgent_high_limited = false;
99 					spin_unlock(&sbi->gc_urgent_high_lock);
100 					sbi->gc_mode = GC_NORMAL;
101 					continue;
102 				}
103 				sbi->gc_urgent_high_remaining--;
104 			}
105 			spin_unlock(&sbi->gc_urgent_high_lock);
106 
107 			wait_ms = gc_th->urgent_sleep_time;
108 			down_write(&sbi->gc_lock);
109 			goto do_gc;
110 		}
111 
112 		if (foreground) {
113 			down_write(&sbi->gc_lock);
114 			goto do_gc;
115 		} else if (!down_write_trylock(&sbi->gc_lock)) {
116 			stat_other_skip_bggc_count(sbi);
117 			goto next;
118 		}
119 
120 		if (!is_idle(sbi, GC_TIME)) {
121 			increase_sleep_time(gc_th, &wait_ms);
122 			up_write(&sbi->gc_lock);
123 			stat_io_skip_bggc_count(sbi);
124 			goto next;
125 		}
126 
127 		if (has_enough_invalid_blocks(sbi))
128 			decrease_sleep_time(gc_th, &wait_ms);
129 		else
130 			increase_sleep_time(gc_th, &wait_ms);
131 do_gc:
132 		if (!foreground)
133 			stat_inc_bggc_count(sbi->stat_info);
134 
135 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
136 
137 		/* foreground GC was been triggered via f2fs_balance_fs() */
138 		if (foreground)
139 			sync_mode = false;
140 
141 		/* if return value is not zero, no victim was selected */
142 		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO))
143 			wait_ms = gc_th->no_gc_sleep_time;
144 
145 		if (foreground)
146 			wake_up_all(&gc_th->fggc_wq);
147 
148 		trace_f2fs_background_gc(sbi->sb, wait_ms,
149 				prefree_segments(sbi), free_segments(sbi));
150 
151 		/* balancing f2fs's metadata periodically */
152 		f2fs_balance_fs_bg(sbi, true);
153 next:
154 		sb_end_write(sbi->sb);
155 
156 	} while (!kthread_should_stop());
157 	return 0;
158 }
159 
160 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
161 {
162 	struct f2fs_gc_kthread *gc_th;
163 	dev_t dev = sbi->sb->s_bdev->bd_dev;
164 	int err = 0;
165 
166 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
167 	if (!gc_th) {
168 		err = -ENOMEM;
169 		goto out;
170 	}
171 
172 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
173 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
174 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
175 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
176 
177 	gc_th->gc_wake = 0;
178 
179 	sbi->gc_thread = gc_th;
180 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
181 	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
182 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
183 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
184 	if (IS_ERR(gc_th->f2fs_gc_task)) {
185 		err = PTR_ERR(gc_th->f2fs_gc_task);
186 		kfree(gc_th);
187 		sbi->gc_thread = NULL;
188 	}
189 out:
190 	return err;
191 }
192 
193 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
194 {
195 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
196 
197 	if (!gc_th)
198 		return;
199 	kthread_stop(gc_th->f2fs_gc_task);
200 	wake_up_all(&gc_th->fggc_wq);
201 	kfree(gc_th);
202 	sbi->gc_thread = NULL;
203 }
204 
205 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
206 {
207 	int gc_mode;
208 
209 	if (gc_type == BG_GC) {
210 		if (sbi->am.atgc_enabled)
211 			gc_mode = GC_AT;
212 		else
213 			gc_mode = GC_CB;
214 	} else {
215 		gc_mode = GC_GREEDY;
216 	}
217 
218 	switch (sbi->gc_mode) {
219 	case GC_IDLE_CB:
220 		gc_mode = GC_CB;
221 		break;
222 	case GC_IDLE_GREEDY:
223 	case GC_URGENT_HIGH:
224 		gc_mode = GC_GREEDY;
225 		break;
226 	case GC_IDLE_AT:
227 		gc_mode = GC_AT;
228 		break;
229 	}
230 
231 	return gc_mode;
232 }
233 
234 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
235 			int type, struct victim_sel_policy *p)
236 {
237 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
238 
239 	if (p->alloc_mode == SSR) {
240 		p->gc_mode = GC_GREEDY;
241 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
242 		p->max_search = dirty_i->nr_dirty[type];
243 		p->ofs_unit = 1;
244 	} else if (p->alloc_mode == AT_SSR) {
245 		p->gc_mode = GC_GREEDY;
246 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
247 		p->max_search = dirty_i->nr_dirty[type];
248 		p->ofs_unit = 1;
249 	} else {
250 		p->gc_mode = select_gc_type(sbi, gc_type);
251 		p->ofs_unit = sbi->segs_per_sec;
252 		if (__is_large_section(sbi)) {
253 			p->dirty_bitmap = dirty_i->dirty_secmap;
254 			p->max_search = count_bits(p->dirty_bitmap,
255 						0, MAIN_SECS(sbi));
256 		} else {
257 			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
258 			p->max_search = dirty_i->nr_dirty[DIRTY];
259 		}
260 	}
261 
262 	/*
263 	 * adjust candidates range, should select all dirty segments for
264 	 * foreground GC and urgent GC cases.
265 	 */
266 	if (gc_type != FG_GC &&
267 			(sbi->gc_mode != GC_URGENT_HIGH) &&
268 			(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
269 			p->max_search > sbi->max_victim_search)
270 		p->max_search = sbi->max_victim_search;
271 
272 	/* let's select beginning hot/small space first in no_heap mode*/
273 	if (f2fs_need_rand_seg(sbi))
274 		p->offset = prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec);
275 	else if (test_opt(sbi, NOHEAP) &&
276 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
277 		p->offset = 0;
278 	else
279 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
280 }
281 
282 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
283 				struct victim_sel_policy *p)
284 {
285 	/* SSR allocates in a segment unit */
286 	if (p->alloc_mode == SSR)
287 		return sbi->blocks_per_seg;
288 	else if (p->alloc_mode == AT_SSR)
289 		return UINT_MAX;
290 
291 	/* LFS */
292 	if (p->gc_mode == GC_GREEDY)
293 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
294 	else if (p->gc_mode == GC_CB)
295 		return UINT_MAX;
296 	else if (p->gc_mode == GC_AT)
297 		return UINT_MAX;
298 	else /* No other gc_mode */
299 		return 0;
300 }
301 
302 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
303 {
304 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
305 	unsigned int secno;
306 
307 	/*
308 	 * If the gc_type is FG_GC, we can select victim segments
309 	 * selected by background GC before.
310 	 * Those segments guarantee they have small valid blocks.
311 	 */
312 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
313 		if (sec_usage_check(sbi, secno))
314 			continue;
315 		clear_bit(secno, dirty_i->victim_secmap);
316 		return GET_SEG_FROM_SEC(sbi, secno);
317 	}
318 	return NULL_SEGNO;
319 }
320 
321 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
322 {
323 	struct sit_info *sit_i = SIT_I(sbi);
324 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
325 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
326 	unsigned long long mtime = 0;
327 	unsigned int vblocks;
328 	unsigned char age = 0;
329 	unsigned char u;
330 	unsigned int i;
331 	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
332 
333 	for (i = 0; i < usable_segs_per_sec; i++)
334 		mtime += get_seg_entry(sbi, start + i)->mtime;
335 	vblocks = get_valid_blocks(sbi, segno, true);
336 
337 	mtime = div_u64(mtime, usable_segs_per_sec);
338 	vblocks = div_u64(vblocks, usable_segs_per_sec);
339 
340 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
341 
342 	/* Handle if the system time has changed by the user */
343 	if (mtime < sit_i->min_mtime)
344 		sit_i->min_mtime = mtime;
345 	if (mtime > sit_i->max_mtime)
346 		sit_i->max_mtime = mtime;
347 	if (sit_i->max_mtime != sit_i->min_mtime)
348 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
349 				sit_i->max_mtime - sit_i->min_mtime);
350 
351 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
352 }
353 
354 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
355 			unsigned int segno, struct victim_sel_policy *p)
356 {
357 	if (p->alloc_mode == SSR)
358 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
359 
360 	/* alloc_mode == LFS */
361 	if (p->gc_mode == GC_GREEDY)
362 		return get_valid_blocks(sbi, segno, true);
363 	else if (p->gc_mode == GC_CB)
364 		return get_cb_cost(sbi, segno);
365 
366 	f2fs_bug_on(sbi, 1);
367 	return 0;
368 }
369 
370 static unsigned int count_bits(const unsigned long *addr,
371 				unsigned int offset, unsigned int len)
372 {
373 	unsigned int end = offset + len, sum = 0;
374 
375 	while (offset < end) {
376 		if (test_bit(offset++, addr))
377 			++sum;
378 	}
379 	return sum;
380 }
381 
382 static struct victim_entry *attach_victim_entry(struct f2fs_sb_info *sbi,
383 				unsigned long long mtime, unsigned int segno,
384 				struct rb_node *parent, struct rb_node **p,
385 				bool left_most)
386 {
387 	struct atgc_management *am = &sbi->am;
388 	struct victim_entry *ve;
389 
390 	ve =  f2fs_kmem_cache_alloc(victim_entry_slab,
391 				GFP_NOFS, true, NULL);
392 
393 	ve->mtime = mtime;
394 	ve->segno = segno;
395 
396 	rb_link_node(&ve->rb_node, parent, p);
397 	rb_insert_color_cached(&ve->rb_node, &am->root, left_most);
398 
399 	list_add_tail(&ve->list, &am->victim_list);
400 
401 	am->victim_count++;
402 
403 	return ve;
404 }
405 
406 static void insert_victim_entry(struct f2fs_sb_info *sbi,
407 				unsigned long long mtime, unsigned int segno)
408 {
409 	struct atgc_management *am = &sbi->am;
410 	struct rb_node **p;
411 	struct rb_node *parent = NULL;
412 	bool left_most = true;
413 
414 	p = f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, mtime, &left_most);
415 	attach_victim_entry(sbi, mtime, segno, parent, p, left_most);
416 }
417 
418 static void add_victim_entry(struct f2fs_sb_info *sbi,
419 				struct victim_sel_policy *p, unsigned int segno)
420 {
421 	struct sit_info *sit_i = SIT_I(sbi);
422 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
423 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
424 	unsigned long long mtime = 0;
425 	unsigned int i;
426 
427 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
428 		if (p->gc_mode == GC_AT &&
429 			get_valid_blocks(sbi, segno, true) == 0)
430 			return;
431 	}
432 
433 	for (i = 0; i < sbi->segs_per_sec; i++)
434 		mtime += get_seg_entry(sbi, start + i)->mtime;
435 	mtime = div_u64(mtime, sbi->segs_per_sec);
436 
437 	/* Handle if the system time has changed by the user */
438 	if (mtime < sit_i->min_mtime)
439 		sit_i->min_mtime = mtime;
440 	if (mtime > sit_i->max_mtime)
441 		sit_i->max_mtime = mtime;
442 	if (mtime < sit_i->dirty_min_mtime)
443 		sit_i->dirty_min_mtime = mtime;
444 	if (mtime > sit_i->dirty_max_mtime)
445 		sit_i->dirty_max_mtime = mtime;
446 
447 	/* don't choose young section as candidate */
448 	if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
449 		return;
450 
451 	insert_victim_entry(sbi, mtime, segno);
452 }
453 
454 static struct rb_node *lookup_central_victim(struct f2fs_sb_info *sbi,
455 						struct victim_sel_policy *p)
456 {
457 	struct atgc_management *am = &sbi->am;
458 	struct rb_node *parent = NULL;
459 	bool left_most;
460 
461 	f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, p->age, &left_most);
462 
463 	return parent;
464 }
465 
466 static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
467 						struct victim_sel_policy *p)
468 {
469 	struct sit_info *sit_i = SIT_I(sbi);
470 	struct atgc_management *am = &sbi->am;
471 	struct rb_root_cached *root = &am->root;
472 	struct rb_node *node;
473 	struct rb_entry *re;
474 	struct victim_entry *ve;
475 	unsigned long long total_time;
476 	unsigned long long age, u, accu;
477 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
478 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
479 	unsigned int sec_blocks = BLKS_PER_SEC(sbi);
480 	unsigned int vblocks;
481 	unsigned int dirty_threshold = max(am->max_candidate_count,
482 					am->candidate_ratio *
483 					am->victim_count / 100);
484 	unsigned int age_weight = am->age_weight;
485 	unsigned int cost;
486 	unsigned int iter = 0;
487 
488 	if (max_mtime < min_mtime)
489 		return;
490 
491 	max_mtime += 1;
492 	total_time = max_mtime - min_mtime;
493 
494 	accu = div64_u64(ULLONG_MAX, total_time);
495 	accu = min_t(unsigned long long, div_u64(accu, 100),
496 					DEFAULT_ACCURACY_CLASS);
497 
498 	node = rb_first_cached(root);
499 next:
500 	re = rb_entry_safe(node, struct rb_entry, rb_node);
501 	if (!re)
502 		return;
503 
504 	ve = (struct victim_entry *)re;
505 
506 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
507 		goto skip;
508 
509 	/* age = 10000 * x% * 60 */
510 	age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
511 								age_weight;
512 
513 	vblocks = get_valid_blocks(sbi, ve->segno, true);
514 	f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
515 
516 	/* u = 10000 * x% * 40 */
517 	u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
518 							(100 - age_weight);
519 
520 	f2fs_bug_on(sbi, age + u >= UINT_MAX);
521 
522 	cost = UINT_MAX - (age + u);
523 	iter++;
524 
525 	if (cost < p->min_cost ||
526 			(cost == p->min_cost && age > p->oldest_age)) {
527 		p->min_cost = cost;
528 		p->oldest_age = age;
529 		p->min_segno = ve->segno;
530 	}
531 skip:
532 	if (iter < dirty_threshold) {
533 		node = rb_next(node);
534 		goto next;
535 	}
536 }
537 
538 /*
539  * select candidates around source section in range of
540  * [target - dirty_threshold, target + dirty_threshold]
541  */
542 static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
543 						struct victim_sel_policy *p)
544 {
545 	struct sit_info *sit_i = SIT_I(sbi);
546 	struct atgc_management *am = &sbi->am;
547 	struct rb_node *node;
548 	struct rb_entry *re;
549 	struct victim_entry *ve;
550 	unsigned long long age;
551 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
552 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
553 	unsigned int seg_blocks = sbi->blocks_per_seg;
554 	unsigned int vblocks;
555 	unsigned int dirty_threshold = max(am->max_candidate_count,
556 					am->candidate_ratio *
557 					am->victim_count / 100);
558 	unsigned int cost;
559 	unsigned int iter = 0;
560 	int stage = 0;
561 
562 	if (max_mtime < min_mtime)
563 		return;
564 	max_mtime += 1;
565 next_stage:
566 	node = lookup_central_victim(sbi, p);
567 next_node:
568 	re = rb_entry_safe(node, struct rb_entry, rb_node);
569 	if (!re) {
570 		if (stage == 0)
571 			goto skip_stage;
572 		return;
573 	}
574 
575 	ve = (struct victim_entry *)re;
576 
577 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
578 		goto skip_node;
579 
580 	age = max_mtime - ve->mtime;
581 
582 	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
583 	f2fs_bug_on(sbi, !vblocks);
584 
585 	/* rare case */
586 	if (vblocks == seg_blocks)
587 		goto skip_node;
588 
589 	iter++;
590 
591 	age = max_mtime - abs(p->age - age);
592 	cost = UINT_MAX - vblocks;
593 
594 	if (cost < p->min_cost ||
595 			(cost == p->min_cost && age > p->oldest_age)) {
596 		p->min_cost = cost;
597 		p->oldest_age = age;
598 		p->min_segno = ve->segno;
599 	}
600 skip_node:
601 	if (iter < dirty_threshold) {
602 		if (stage == 0)
603 			node = rb_prev(node);
604 		else if (stage == 1)
605 			node = rb_next(node);
606 		goto next_node;
607 	}
608 skip_stage:
609 	if (stage < 1) {
610 		stage++;
611 		iter = 0;
612 		goto next_stage;
613 	}
614 }
615 static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
616 						struct victim_sel_policy *p)
617 {
618 	f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
619 						&sbi->am.root, true));
620 
621 	if (p->gc_mode == GC_AT)
622 		atgc_lookup_victim(sbi, p);
623 	else if (p->alloc_mode == AT_SSR)
624 		atssr_lookup_victim(sbi, p);
625 	else
626 		f2fs_bug_on(sbi, 1);
627 }
628 
629 static void release_victim_entry(struct f2fs_sb_info *sbi)
630 {
631 	struct atgc_management *am = &sbi->am;
632 	struct victim_entry *ve, *tmp;
633 
634 	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
635 		list_del(&ve->list);
636 		kmem_cache_free(victim_entry_slab, ve);
637 		am->victim_count--;
638 	}
639 
640 	am->root = RB_ROOT_CACHED;
641 
642 	f2fs_bug_on(sbi, am->victim_count);
643 	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
644 }
645 
646 /*
647  * This function is called from two paths.
648  * One is garbage collection and the other is SSR segment selection.
649  * When it is called during GC, it just gets a victim segment
650  * and it does not remove it from dirty seglist.
651  * When it is called from SSR segment selection, it finds a segment
652  * which has minimum valid blocks and removes it from dirty seglist.
653  */
654 static int get_victim_by_default(struct f2fs_sb_info *sbi,
655 			unsigned int *result, int gc_type, int type,
656 			char alloc_mode, unsigned long long age)
657 {
658 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
659 	struct sit_info *sm = SIT_I(sbi);
660 	struct victim_sel_policy p;
661 	unsigned int secno, last_victim;
662 	unsigned int last_segment;
663 	unsigned int nsearched;
664 	bool is_atgc;
665 	int ret = 0;
666 
667 	mutex_lock(&dirty_i->seglist_lock);
668 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
669 
670 	p.alloc_mode = alloc_mode;
671 	p.age = age;
672 	p.age_threshold = sbi->am.age_threshold;
673 
674 retry:
675 	select_policy(sbi, gc_type, type, &p);
676 	p.min_segno = NULL_SEGNO;
677 	p.oldest_age = 0;
678 	p.min_cost = get_max_cost(sbi, &p);
679 
680 	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
681 	nsearched = 0;
682 
683 	if (is_atgc)
684 		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
685 
686 	if (*result != NULL_SEGNO) {
687 		if (!get_valid_blocks(sbi, *result, false)) {
688 			ret = -ENODATA;
689 			goto out;
690 		}
691 
692 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
693 			ret = -EBUSY;
694 		else
695 			p.min_segno = *result;
696 		goto out;
697 	}
698 
699 	ret = -ENODATA;
700 	if (p.max_search == 0)
701 		goto out;
702 
703 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
704 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
705 			p.min_segno = sbi->next_victim_seg[BG_GC];
706 			*result = p.min_segno;
707 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
708 			goto got_result;
709 		}
710 		if (gc_type == FG_GC &&
711 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
712 			p.min_segno = sbi->next_victim_seg[FG_GC];
713 			*result = p.min_segno;
714 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
715 			goto got_result;
716 		}
717 	}
718 
719 	last_victim = sm->last_victim[p.gc_mode];
720 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
721 		p.min_segno = check_bg_victims(sbi);
722 		if (p.min_segno != NULL_SEGNO)
723 			goto got_it;
724 	}
725 
726 	while (1) {
727 		unsigned long cost, *dirty_bitmap;
728 		unsigned int unit_no, segno;
729 
730 		dirty_bitmap = p.dirty_bitmap;
731 		unit_no = find_next_bit(dirty_bitmap,
732 				last_segment / p.ofs_unit,
733 				p.offset / p.ofs_unit);
734 		segno = unit_no * p.ofs_unit;
735 		if (segno >= last_segment) {
736 			if (sm->last_victim[p.gc_mode]) {
737 				last_segment =
738 					sm->last_victim[p.gc_mode];
739 				sm->last_victim[p.gc_mode] = 0;
740 				p.offset = 0;
741 				continue;
742 			}
743 			break;
744 		}
745 
746 		p.offset = segno + p.ofs_unit;
747 		nsearched++;
748 
749 #ifdef CONFIG_F2FS_CHECK_FS
750 		/*
751 		 * skip selecting the invalid segno (that is failed due to block
752 		 * validity check failure during GC) to avoid endless GC loop in
753 		 * such cases.
754 		 */
755 		if (test_bit(segno, sm->invalid_segmap))
756 			goto next;
757 #endif
758 
759 		secno = GET_SEC_FROM_SEG(sbi, segno);
760 
761 		if (sec_usage_check(sbi, secno))
762 			goto next;
763 
764 		/* Don't touch checkpointed data */
765 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
766 			if (p.alloc_mode == LFS) {
767 				/*
768 				 * LFS is set to find source section during GC.
769 				 * The victim should have no checkpointed data.
770 				 */
771 				if (get_ckpt_valid_blocks(sbi, segno, true))
772 					goto next;
773 			} else {
774 				/*
775 				 * SSR | AT_SSR are set to find target segment
776 				 * for writes which can be full by checkpointed
777 				 * and newly written blocks.
778 				 */
779 				if (!f2fs_segment_has_free_slot(sbi, segno))
780 					goto next;
781 			}
782 		}
783 
784 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
785 			goto next;
786 
787 		if (is_atgc) {
788 			add_victim_entry(sbi, &p, segno);
789 			goto next;
790 		}
791 
792 		cost = get_gc_cost(sbi, segno, &p);
793 
794 		if (p.min_cost > cost) {
795 			p.min_segno = segno;
796 			p.min_cost = cost;
797 		}
798 next:
799 		if (nsearched >= p.max_search) {
800 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
801 				sm->last_victim[p.gc_mode] =
802 					last_victim + p.ofs_unit;
803 			else
804 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
805 			sm->last_victim[p.gc_mode] %=
806 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
807 			break;
808 		}
809 	}
810 
811 	/* get victim for GC_AT/AT_SSR */
812 	if (is_atgc) {
813 		lookup_victim_by_age(sbi, &p);
814 		release_victim_entry(sbi);
815 	}
816 
817 	if (is_atgc && p.min_segno == NULL_SEGNO &&
818 			sm->elapsed_time < p.age_threshold) {
819 		p.age_threshold = 0;
820 		goto retry;
821 	}
822 
823 	if (p.min_segno != NULL_SEGNO) {
824 got_it:
825 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
826 got_result:
827 		if (p.alloc_mode == LFS) {
828 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
829 			if (gc_type == FG_GC)
830 				sbi->cur_victim_sec = secno;
831 			else
832 				set_bit(secno, dirty_i->victim_secmap);
833 		}
834 		ret = 0;
835 
836 	}
837 out:
838 	if (p.min_segno != NULL_SEGNO)
839 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
840 				sbi->cur_victim_sec,
841 				prefree_segments(sbi), free_segments(sbi));
842 	mutex_unlock(&dirty_i->seglist_lock);
843 
844 	return ret;
845 }
846 
847 static const struct victim_selection default_v_ops = {
848 	.get_victim = get_victim_by_default,
849 };
850 
851 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
852 {
853 	struct inode_entry *ie;
854 
855 	ie = radix_tree_lookup(&gc_list->iroot, ino);
856 	if (ie)
857 		return ie->inode;
858 	return NULL;
859 }
860 
861 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
862 {
863 	struct inode_entry *new_ie;
864 
865 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
866 		iput(inode);
867 		return;
868 	}
869 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
870 					GFP_NOFS, true, NULL);
871 	new_ie->inode = inode;
872 
873 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
874 	list_add_tail(&new_ie->list, &gc_list->ilist);
875 }
876 
877 static void put_gc_inode(struct gc_inode_list *gc_list)
878 {
879 	struct inode_entry *ie, *next_ie;
880 
881 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
882 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
883 		iput(ie->inode);
884 		list_del(&ie->list);
885 		kmem_cache_free(f2fs_inode_entry_slab, ie);
886 	}
887 }
888 
889 static int check_valid_map(struct f2fs_sb_info *sbi,
890 				unsigned int segno, int offset)
891 {
892 	struct sit_info *sit_i = SIT_I(sbi);
893 	struct seg_entry *sentry;
894 	int ret;
895 
896 	down_read(&sit_i->sentry_lock);
897 	sentry = get_seg_entry(sbi, segno);
898 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
899 	up_read(&sit_i->sentry_lock);
900 	return ret;
901 }
902 
903 /*
904  * This function compares node address got in summary with that in NAT.
905  * On validity, copy that node with cold status, otherwise (invalid node)
906  * ignore that.
907  */
908 static int gc_node_segment(struct f2fs_sb_info *sbi,
909 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
910 {
911 	struct f2fs_summary *entry;
912 	block_t start_addr;
913 	int off;
914 	int phase = 0;
915 	bool fggc = (gc_type == FG_GC);
916 	int submitted = 0;
917 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
918 
919 	start_addr = START_BLOCK(sbi, segno);
920 
921 next_step:
922 	entry = sum;
923 
924 	if (fggc && phase == 2)
925 		atomic_inc(&sbi->wb_sync_req[NODE]);
926 
927 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
928 		nid_t nid = le32_to_cpu(entry->nid);
929 		struct page *node_page;
930 		struct node_info ni;
931 		int err;
932 
933 		/* stop BG_GC if there is not enough free sections. */
934 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
935 			return submitted;
936 
937 		if (check_valid_map(sbi, segno, off) == 0)
938 			continue;
939 
940 		if (phase == 0) {
941 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
942 							META_NAT, true);
943 			continue;
944 		}
945 
946 		if (phase == 1) {
947 			f2fs_ra_node_page(sbi, nid);
948 			continue;
949 		}
950 
951 		/* phase == 2 */
952 		node_page = f2fs_get_node_page(sbi, nid);
953 		if (IS_ERR(node_page))
954 			continue;
955 
956 		/* block may become invalid during f2fs_get_node_page */
957 		if (check_valid_map(sbi, segno, off) == 0) {
958 			f2fs_put_page(node_page, 1);
959 			continue;
960 		}
961 
962 		if (f2fs_get_node_info(sbi, nid, &ni, false)) {
963 			f2fs_put_page(node_page, 1);
964 			continue;
965 		}
966 
967 		if (ni.blk_addr != start_addr + off) {
968 			f2fs_put_page(node_page, 1);
969 			continue;
970 		}
971 
972 		err = f2fs_move_node_page(node_page, gc_type);
973 		if (!err && gc_type == FG_GC)
974 			submitted++;
975 		stat_inc_node_blk_count(sbi, 1, gc_type);
976 	}
977 
978 	if (++phase < 3)
979 		goto next_step;
980 
981 	if (fggc)
982 		atomic_dec(&sbi->wb_sync_req[NODE]);
983 	return submitted;
984 }
985 
986 /*
987  * Calculate start block index indicating the given node offset.
988  * Be careful, caller should give this node offset only indicating direct node
989  * blocks. If any node offsets, which point the other types of node blocks such
990  * as indirect or double indirect node blocks, are given, it must be a caller's
991  * bug.
992  */
993 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
994 {
995 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
996 	unsigned int bidx;
997 
998 	if (node_ofs == 0)
999 		return 0;
1000 
1001 	if (node_ofs <= 2) {
1002 		bidx = node_ofs - 1;
1003 	} else if (node_ofs <= indirect_blks) {
1004 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
1005 
1006 		bidx = node_ofs - 2 - dec;
1007 	} else {
1008 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
1009 
1010 		bidx = node_ofs - 5 - dec;
1011 	}
1012 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
1013 }
1014 
1015 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1016 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
1017 {
1018 	struct page *node_page;
1019 	nid_t nid;
1020 	unsigned int ofs_in_node;
1021 	block_t source_blkaddr;
1022 
1023 	nid = le32_to_cpu(sum->nid);
1024 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
1025 
1026 	node_page = f2fs_get_node_page(sbi, nid);
1027 	if (IS_ERR(node_page))
1028 		return false;
1029 
1030 	if (f2fs_get_node_info(sbi, nid, dni, false)) {
1031 		f2fs_put_page(node_page, 1);
1032 		return false;
1033 	}
1034 
1035 	if (sum->version != dni->version) {
1036 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
1037 			  __func__);
1038 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1039 	}
1040 
1041 	if (f2fs_check_nid_range(sbi, dni->ino))
1042 		return false;
1043 
1044 	*nofs = ofs_of_node(node_page);
1045 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
1046 	f2fs_put_page(node_page, 1);
1047 
1048 	if (source_blkaddr != blkaddr) {
1049 #ifdef CONFIG_F2FS_CHECK_FS
1050 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
1051 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
1052 
1053 		if (unlikely(check_valid_map(sbi, segno, offset))) {
1054 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
1055 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
1056 					 blkaddr, source_blkaddr, segno);
1057 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1058 			}
1059 		}
1060 #endif
1061 		return false;
1062 	}
1063 	return true;
1064 }
1065 
1066 static int ra_data_block(struct inode *inode, pgoff_t index)
1067 {
1068 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1069 	struct address_space *mapping = inode->i_mapping;
1070 	struct dnode_of_data dn;
1071 	struct page *page;
1072 	struct extent_info ei = {0, 0, 0};
1073 	struct f2fs_io_info fio = {
1074 		.sbi = sbi,
1075 		.ino = inode->i_ino,
1076 		.type = DATA,
1077 		.temp = COLD,
1078 		.op = REQ_OP_READ,
1079 		.op_flags = 0,
1080 		.encrypted_page = NULL,
1081 		.in_list = false,
1082 		.retry = false,
1083 	};
1084 	int err;
1085 
1086 	page = f2fs_grab_cache_page(mapping, index, true);
1087 	if (!page)
1088 		return -ENOMEM;
1089 
1090 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
1091 		dn.data_blkaddr = ei.blk + index - ei.fofs;
1092 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1093 						DATA_GENERIC_ENHANCE_READ))) {
1094 			err = -EFSCORRUPTED;
1095 			goto put_page;
1096 		}
1097 		goto got_it;
1098 	}
1099 
1100 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1101 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1102 	if (err)
1103 		goto put_page;
1104 	f2fs_put_dnode(&dn);
1105 
1106 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1107 		err = -ENOENT;
1108 		goto put_page;
1109 	}
1110 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1111 						DATA_GENERIC_ENHANCE))) {
1112 		err = -EFSCORRUPTED;
1113 		goto put_page;
1114 	}
1115 got_it:
1116 	/* read page */
1117 	fio.page = page;
1118 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1119 
1120 	/*
1121 	 * don't cache encrypted data into meta inode until previous dirty
1122 	 * data were writebacked to avoid racing between GC and flush.
1123 	 */
1124 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1125 
1126 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1127 
1128 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1129 					dn.data_blkaddr,
1130 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1131 	if (!fio.encrypted_page) {
1132 		err = -ENOMEM;
1133 		goto put_page;
1134 	}
1135 
1136 	err = f2fs_submit_page_bio(&fio);
1137 	if (err)
1138 		goto put_encrypted_page;
1139 	f2fs_put_page(fio.encrypted_page, 0);
1140 	f2fs_put_page(page, 1);
1141 
1142 	f2fs_update_iostat(sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
1143 	f2fs_update_iostat(sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1144 
1145 	return 0;
1146 put_encrypted_page:
1147 	f2fs_put_page(fio.encrypted_page, 1);
1148 put_page:
1149 	f2fs_put_page(page, 1);
1150 	return err;
1151 }
1152 
1153 /*
1154  * Move data block via META_MAPPING while keeping locked data page.
1155  * This can be used to move blocks, aka LBAs, directly on disk.
1156  */
1157 static int move_data_block(struct inode *inode, block_t bidx,
1158 				int gc_type, unsigned int segno, int off)
1159 {
1160 	struct f2fs_io_info fio = {
1161 		.sbi = F2FS_I_SB(inode),
1162 		.ino = inode->i_ino,
1163 		.type = DATA,
1164 		.temp = COLD,
1165 		.op = REQ_OP_READ,
1166 		.op_flags = 0,
1167 		.encrypted_page = NULL,
1168 		.in_list = false,
1169 		.retry = false,
1170 	};
1171 	struct dnode_of_data dn;
1172 	struct f2fs_summary sum;
1173 	struct node_info ni;
1174 	struct page *page, *mpage;
1175 	block_t newaddr;
1176 	int err = 0;
1177 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1178 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1179 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1180 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1181 
1182 	/* do not read out */
1183 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
1184 	if (!page)
1185 		return -ENOMEM;
1186 
1187 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1188 		err = -ENOENT;
1189 		goto out;
1190 	}
1191 
1192 	if (f2fs_is_atomic_file(inode)) {
1193 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
1194 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
1195 		err = -EAGAIN;
1196 		goto out;
1197 	}
1198 
1199 	if (f2fs_is_pinned_file(inode)) {
1200 		f2fs_pin_file_control(inode, true);
1201 		err = -EAGAIN;
1202 		goto out;
1203 	}
1204 
1205 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1206 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1207 	if (err)
1208 		goto out;
1209 
1210 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1211 		ClearPageUptodate(page);
1212 		err = -ENOENT;
1213 		goto put_out;
1214 	}
1215 
1216 	/*
1217 	 * don't cache encrypted data into meta inode until previous dirty
1218 	 * data were writebacked to avoid racing between GC and flush.
1219 	 */
1220 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1221 
1222 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1223 
1224 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni, false);
1225 	if (err)
1226 		goto put_out;
1227 
1228 	/* read page */
1229 	fio.page = page;
1230 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1231 
1232 	if (lfs_mode)
1233 		down_write(&fio.sbi->io_order_lock);
1234 
1235 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1236 					fio.old_blkaddr, false);
1237 	if (!mpage) {
1238 		err = -ENOMEM;
1239 		goto up_out;
1240 	}
1241 
1242 	fio.encrypted_page = mpage;
1243 
1244 	/* read source block in mpage */
1245 	if (!PageUptodate(mpage)) {
1246 		err = f2fs_submit_page_bio(&fio);
1247 		if (err) {
1248 			f2fs_put_page(mpage, 1);
1249 			goto up_out;
1250 		}
1251 
1252 		f2fs_update_iostat(fio.sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
1253 		f2fs_update_iostat(fio.sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1254 
1255 		lock_page(mpage);
1256 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1257 						!PageUptodate(mpage))) {
1258 			err = -EIO;
1259 			f2fs_put_page(mpage, 1);
1260 			goto up_out;
1261 		}
1262 	}
1263 
1264 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1265 
1266 	/* allocate block address */
1267 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1268 				&sum, type, NULL);
1269 
1270 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
1271 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
1272 	if (!fio.encrypted_page) {
1273 		err = -ENOMEM;
1274 		f2fs_put_page(mpage, 1);
1275 		goto recover_block;
1276 	}
1277 
1278 	/* write target block */
1279 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
1280 	memcpy(page_address(fio.encrypted_page),
1281 				page_address(mpage), PAGE_SIZE);
1282 	f2fs_put_page(mpage, 1);
1283 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
1284 				fio.old_blkaddr, fio.old_blkaddr);
1285 	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
1286 
1287 	set_page_dirty(fio.encrypted_page);
1288 	if (clear_page_dirty_for_io(fio.encrypted_page))
1289 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1290 
1291 	set_page_writeback(fio.encrypted_page);
1292 	ClearPageError(page);
1293 
1294 	fio.op = REQ_OP_WRITE;
1295 	fio.op_flags = REQ_SYNC;
1296 	fio.new_blkaddr = newaddr;
1297 	f2fs_submit_page_write(&fio);
1298 	if (fio.retry) {
1299 		err = -EAGAIN;
1300 		if (PageWriteback(fio.encrypted_page))
1301 			end_page_writeback(fio.encrypted_page);
1302 		goto put_page_out;
1303 	}
1304 
1305 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
1306 
1307 	f2fs_update_data_blkaddr(&dn, newaddr);
1308 	set_inode_flag(inode, FI_APPEND_WRITE);
1309 	if (page->index == 0)
1310 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1311 put_page_out:
1312 	f2fs_put_page(fio.encrypted_page, 1);
1313 recover_block:
1314 	if (err)
1315 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1316 							true, true, true);
1317 up_out:
1318 	if (lfs_mode)
1319 		up_write(&fio.sbi->io_order_lock);
1320 put_out:
1321 	f2fs_put_dnode(&dn);
1322 out:
1323 	f2fs_put_page(page, 1);
1324 	return err;
1325 }
1326 
1327 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1328 							unsigned int segno, int off)
1329 {
1330 	struct page *page;
1331 	int err = 0;
1332 
1333 	page = f2fs_get_lock_data_page(inode, bidx, true);
1334 	if (IS_ERR(page))
1335 		return PTR_ERR(page);
1336 
1337 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1338 		err = -ENOENT;
1339 		goto out;
1340 	}
1341 
1342 	if (f2fs_is_atomic_file(inode)) {
1343 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
1344 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
1345 		err = -EAGAIN;
1346 		goto out;
1347 	}
1348 	if (f2fs_is_pinned_file(inode)) {
1349 		if (gc_type == FG_GC)
1350 			f2fs_pin_file_control(inode, true);
1351 		err = -EAGAIN;
1352 		goto out;
1353 	}
1354 
1355 	if (gc_type == BG_GC) {
1356 		if (PageWriteback(page)) {
1357 			err = -EAGAIN;
1358 			goto out;
1359 		}
1360 		set_page_dirty(page);
1361 		set_page_private_gcing(page);
1362 	} else {
1363 		struct f2fs_io_info fio = {
1364 			.sbi = F2FS_I_SB(inode),
1365 			.ino = inode->i_ino,
1366 			.type = DATA,
1367 			.temp = COLD,
1368 			.op = REQ_OP_WRITE,
1369 			.op_flags = REQ_SYNC,
1370 			.old_blkaddr = NULL_ADDR,
1371 			.page = page,
1372 			.encrypted_page = NULL,
1373 			.need_lock = LOCK_REQ,
1374 			.io_type = FS_GC_DATA_IO,
1375 		};
1376 		bool is_dirty = PageDirty(page);
1377 
1378 retry:
1379 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1380 
1381 		set_page_dirty(page);
1382 		if (clear_page_dirty_for_io(page)) {
1383 			inode_dec_dirty_pages(inode);
1384 			f2fs_remove_dirty_inode(inode);
1385 		}
1386 
1387 		set_page_private_gcing(page);
1388 
1389 		err = f2fs_do_write_data_page(&fio);
1390 		if (err) {
1391 			clear_page_private_gcing(page);
1392 			if (err == -ENOMEM) {
1393 				memalloc_retry_wait(GFP_NOFS);
1394 				goto retry;
1395 			}
1396 			if (is_dirty)
1397 				set_page_dirty(page);
1398 		}
1399 	}
1400 out:
1401 	f2fs_put_page(page, 1);
1402 	return err;
1403 }
1404 
1405 /*
1406  * This function tries to get parent node of victim data block, and identifies
1407  * data block validity. If the block is valid, copy that with cold status and
1408  * modify parent node.
1409  * If the parent node is not valid or the data block address is different,
1410  * the victim data block is ignored.
1411  */
1412 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1413 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1414 		bool force_migrate)
1415 {
1416 	struct super_block *sb = sbi->sb;
1417 	struct f2fs_summary *entry;
1418 	block_t start_addr;
1419 	int off;
1420 	int phase = 0;
1421 	int submitted = 0;
1422 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1423 
1424 	start_addr = START_BLOCK(sbi, segno);
1425 
1426 next_step:
1427 	entry = sum;
1428 
1429 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1430 		struct page *data_page;
1431 		struct inode *inode;
1432 		struct node_info dni; /* dnode info for the data */
1433 		unsigned int ofs_in_node, nofs;
1434 		block_t start_bidx;
1435 		nid_t nid = le32_to_cpu(entry->nid);
1436 
1437 		/*
1438 		 * stop BG_GC if there is not enough free sections.
1439 		 * Or, stop GC if the segment becomes fully valid caused by
1440 		 * race condition along with SSR block allocation.
1441 		 */
1442 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1443 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1444 							BLKS_PER_SEC(sbi)))
1445 			return submitted;
1446 
1447 		if (check_valid_map(sbi, segno, off) == 0)
1448 			continue;
1449 
1450 		if (phase == 0) {
1451 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1452 							META_NAT, true);
1453 			continue;
1454 		}
1455 
1456 		if (phase == 1) {
1457 			f2fs_ra_node_page(sbi, nid);
1458 			continue;
1459 		}
1460 
1461 		/* Get an inode by ino with checking validity */
1462 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1463 			continue;
1464 
1465 		if (phase == 2) {
1466 			f2fs_ra_node_page(sbi, dni.ino);
1467 			continue;
1468 		}
1469 
1470 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1471 
1472 		if (phase == 3) {
1473 			inode = f2fs_iget(sb, dni.ino);
1474 			if (IS_ERR(inode) || is_bad_inode(inode) ||
1475 					special_file(inode->i_mode))
1476 				continue;
1477 
1478 			if (!down_write_trylock(
1479 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1480 				iput(inode);
1481 				sbi->skipped_gc_rwsem++;
1482 				continue;
1483 			}
1484 
1485 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1486 								ofs_in_node;
1487 
1488 			if (f2fs_post_read_required(inode)) {
1489 				int err = ra_data_block(inode, start_bidx);
1490 
1491 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1492 				if (err) {
1493 					iput(inode);
1494 					continue;
1495 				}
1496 				add_gc_inode(gc_list, inode);
1497 				continue;
1498 			}
1499 
1500 			data_page = f2fs_get_read_data_page(inode,
1501 						start_bidx, REQ_RAHEAD, true);
1502 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1503 			if (IS_ERR(data_page)) {
1504 				iput(inode);
1505 				continue;
1506 			}
1507 
1508 			f2fs_put_page(data_page, 0);
1509 			add_gc_inode(gc_list, inode);
1510 			continue;
1511 		}
1512 
1513 		/* phase 4 */
1514 		inode = find_gc_inode(gc_list, dni.ino);
1515 		if (inode) {
1516 			struct f2fs_inode_info *fi = F2FS_I(inode);
1517 			bool locked = false;
1518 			int err;
1519 
1520 			if (S_ISREG(inode->i_mode)) {
1521 				if (!down_write_trylock(&fi->i_gc_rwsem[READ])) {
1522 					sbi->skipped_gc_rwsem++;
1523 					continue;
1524 				}
1525 				if (!down_write_trylock(
1526 						&fi->i_gc_rwsem[WRITE])) {
1527 					sbi->skipped_gc_rwsem++;
1528 					up_write(&fi->i_gc_rwsem[READ]);
1529 					continue;
1530 				}
1531 				locked = true;
1532 
1533 				/* wait for all inflight aio data */
1534 				inode_dio_wait(inode);
1535 			}
1536 
1537 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1538 								+ ofs_in_node;
1539 			if (f2fs_post_read_required(inode))
1540 				err = move_data_block(inode, start_bidx,
1541 							gc_type, segno, off);
1542 			else
1543 				err = move_data_page(inode, start_bidx, gc_type,
1544 								segno, off);
1545 
1546 			if (!err && (gc_type == FG_GC ||
1547 					f2fs_post_read_required(inode)))
1548 				submitted++;
1549 
1550 			if (locked) {
1551 				up_write(&fi->i_gc_rwsem[WRITE]);
1552 				up_write(&fi->i_gc_rwsem[READ]);
1553 			}
1554 
1555 			stat_inc_data_blk_count(sbi, 1, gc_type);
1556 		}
1557 	}
1558 
1559 	if (++phase < 5)
1560 		goto next_step;
1561 
1562 	return submitted;
1563 }
1564 
1565 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1566 			int gc_type)
1567 {
1568 	struct sit_info *sit_i = SIT_I(sbi);
1569 	int ret;
1570 
1571 	down_write(&sit_i->sentry_lock);
1572 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1573 					      NO_CHECK_TYPE, LFS, 0);
1574 	up_write(&sit_i->sentry_lock);
1575 	return ret;
1576 }
1577 
1578 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1579 				unsigned int start_segno,
1580 				struct gc_inode_list *gc_list, int gc_type,
1581 				bool force_migrate)
1582 {
1583 	struct page *sum_page;
1584 	struct f2fs_summary_block *sum;
1585 	struct blk_plug plug;
1586 	unsigned int segno = start_segno;
1587 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1588 	int seg_freed = 0, migrated = 0;
1589 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1590 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1591 	int submitted = 0;
1592 
1593 	if (__is_large_section(sbi))
1594 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1595 
1596 	/*
1597 	 * zone-capacity can be less than zone-size in zoned devices,
1598 	 * resulting in less than expected usable segments in the zone,
1599 	 * calculate the end segno in the zone which can be garbage collected
1600 	 */
1601 	if (f2fs_sb_has_blkzoned(sbi))
1602 		end_segno -= sbi->segs_per_sec -
1603 					f2fs_usable_segs_in_sec(sbi, segno);
1604 
1605 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1606 
1607 	/* readahead multi ssa blocks those have contiguous address */
1608 	if (__is_large_section(sbi))
1609 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1610 					end_segno - segno, META_SSA, true);
1611 
1612 	/* reference all summary page */
1613 	while (segno < end_segno) {
1614 		sum_page = f2fs_get_sum_page(sbi, segno++);
1615 		if (IS_ERR(sum_page)) {
1616 			int err = PTR_ERR(sum_page);
1617 
1618 			end_segno = segno - 1;
1619 			for (segno = start_segno; segno < end_segno; segno++) {
1620 				sum_page = find_get_page(META_MAPPING(sbi),
1621 						GET_SUM_BLOCK(sbi, segno));
1622 				f2fs_put_page(sum_page, 0);
1623 				f2fs_put_page(sum_page, 0);
1624 			}
1625 			return err;
1626 		}
1627 		unlock_page(sum_page);
1628 	}
1629 
1630 	blk_start_plug(&plug);
1631 
1632 	for (segno = start_segno; segno < end_segno; segno++) {
1633 
1634 		/* find segment summary of victim */
1635 		sum_page = find_get_page(META_MAPPING(sbi),
1636 					GET_SUM_BLOCK(sbi, segno));
1637 		f2fs_put_page(sum_page, 0);
1638 
1639 		if (get_valid_blocks(sbi, segno, false) == 0)
1640 			goto freed;
1641 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1642 				migrated >= sbi->migration_granularity)
1643 			goto skip;
1644 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1645 			goto skip;
1646 
1647 		sum = page_address(sum_page);
1648 		if (type != GET_SUM_TYPE((&sum->footer))) {
1649 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1650 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1651 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1652 			f2fs_stop_checkpoint(sbi, false);
1653 			goto skip;
1654 		}
1655 
1656 		/*
1657 		 * this is to avoid deadlock:
1658 		 * - lock_page(sum_page)         - f2fs_replace_block
1659 		 *  - check_valid_map()            - down_write(sentry_lock)
1660 		 *   - down_read(sentry_lock)     - change_curseg()
1661 		 *                                  - lock_page(sum_page)
1662 		 */
1663 		if (type == SUM_TYPE_NODE)
1664 			submitted += gc_node_segment(sbi, sum->entries, segno,
1665 								gc_type);
1666 		else
1667 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1668 							segno, gc_type,
1669 							force_migrate);
1670 
1671 		stat_inc_seg_count(sbi, type, gc_type);
1672 		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
1673 		migrated++;
1674 
1675 freed:
1676 		if (gc_type == FG_GC &&
1677 				get_valid_blocks(sbi, segno, false) == 0)
1678 			seg_freed++;
1679 
1680 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1681 			sbi->next_victim_seg[gc_type] = segno + 1;
1682 skip:
1683 		f2fs_put_page(sum_page, 0);
1684 	}
1685 
1686 	if (submitted)
1687 		f2fs_submit_merged_write(sbi,
1688 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1689 
1690 	blk_finish_plug(&plug);
1691 
1692 	stat_inc_call_count(sbi->stat_info);
1693 
1694 	return seg_freed;
1695 }
1696 
1697 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1698 			bool background, bool force, unsigned int segno)
1699 {
1700 	int gc_type = sync ? FG_GC : BG_GC;
1701 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1702 	int ret = 0;
1703 	struct cp_control cpc;
1704 	unsigned int init_segno = segno;
1705 	struct gc_inode_list gc_list = {
1706 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1707 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1708 	};
1709 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1710 	unsigned long long first_skipped;
1711 	unsigned int skipped_round = 0, round = 0;
1712 
1713 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1714 				get_pages(sbi, F2FS_DIRTY_NODES),
1715 				get_pages(sbi, F2FS_DIRTY_DENTS),
1716 				get_pages(sbi, F2FS_DIRTY_IMETA),
1717 				free_sections(sbi),
1718 				free_segments(sbi),
1719 				reserved_segments(sbi),
1720 				prefree_segments(sbi));
1721 
1722 	cpc.reason = __get_cp_reason(sbi);
1723 	sbi->skipped_gc_rwsem = 0;
1724 	first_skipped = last_skipped;
1725 gc_more:
1726 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1727 		ret = -EINVAL;
1728 		goto stop;
1729 	}
1730 	if (unlikely(f2fs_cp_error(sbi))) {
1731 		ret = -EIO;
1732 		goto stop;
1733 	}
1734 
1735 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1736 		/*
1737 		 * For example, if there are many prefree_segments below given
1738 		 * threshold, we can make them free by checkpoint. Then, we
1739 		 * secure free segments which doesn't need fggc any more.
1740 		 */
1741 		if (prefree_segments(sbi) &&
1742 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1743 			ret = f2fs_write_checkpoint(sbi, &cpc);
1744 			if (ret)
1745 				goto stop;
1746 		}
1747 		if (has_not_enough_free_secs(sbi, 0, 0))
1748 			gc_type = FG_GC;
1749 	}
1750 
1751 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1752 	if (gc_type == BG_GC && !background) {
1753 		ret = -EINVAL;
1754 		goto stop;
1755 	}
1756 	ret = __get_victim(sbi, &segno, gc_type);
1757 	if (ret)
1758 		goto stop;
1759 
1760 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type, force);
1761 	if (gc_type == FG_GC &&
1762 		seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
1763 		sec_freed++;
1764 	total_freed += seg_freed;
1765 
1766 	if (gc_type == FG_GC) {
1767 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1768 						sbi->skipped_gc_rwsem)
1769 			skipped_round++;
1770 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1771 		round++;
1772 	}
1773 
1774 	if (gc_type == FG_GC)
1775 		sbi->cur_victim_sec = NULL_SEGNO;
1776 
1777 	if (sync)
1778 		goto stop;
1779 
1780 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1781 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1782 					skipped_round * 2 < round) {
1783 			segno = NULL_SEGNO;
1784 			goto gc_more;
1785 		}
1786 
1787 		if (first_skipped < last_skipped &&
1788 				(last_skipped - first_skipped) >
1789 						sbi->skipped_gc_rwsem) {
1790 			f2fs_drop_inmem_pages_all(sbi, true);
1791 			segno = NULL_SEGNO;
1792 			goto gc_more;
1793 		}
1794 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1795 			ret = f2fs_write_checkpoint(sbi, &cpc);
1796 	}
1797 stop:
1798 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1799 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1800 
1801 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1802 				get_pages(sbi, F2FS_DIRTY_NODES),
1803 				get_pages(sbi, F2FS_DIRTY_DENTS),
1804 				get_pages(sbi, F2FS_DIRTY_IMETA),
1805 				free_sections(sbi),
1806 				free_segments(sbi),
1807 				reserved_segments(sbi),
1808 				prefree_segments(sbi));
1809 
1810 	up_write(&sbi->gc_lock);
1811 
1812 	put_gc_inode(&gc_list);
1813 
1814 	if (sync && !ret)
1815 		ret = sec_freed ? 0 : -EAGAIN;
1816 	return ret;
1817 }
1818 
1819 int __init f2fs_create_garbage_collection_cache(void)
1820 {
1821 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1822 					sizeof(struct victim_entry));
1823 	if (!victim_entry_slab)
1824 		return -ENOMEM;
1825 	return 0;
1826 }
1827 
1828 void f2fs_destroy_garbage_collection_cache(void)
1829 {
1830 	kmem_cache_destroy(victim_entry_slab);
1831 }
1832 
1833 static void init_atgc_management(struct f2fs_sb_info *sbi)
1834 {
1835 	struct atgc_management *am = &sbi->am;
1836 
1837 	if (test_opt(sbi, ATGC) &&
1838 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1839 		am->atgc_enabled = true;
1840 
1841 	am->root = RB_ROOT_CACHED;
1842 	INIT_LIST_HEAD(&am->victim_list);
1843 	am->victim_count = 0;
1844 
1845 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1846 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1847 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1848 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1849 }
1850 
1851 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1852 {
1853 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1854 
1855 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1856 
1857 	/* give warm/cold data area from slower device */
1858 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1859 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1860 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1861 
1862 	init_atgc_management(sbi);
1863 }
1864 
1865 static int free_segment_range(struct f2fs_sb_info *sbi,
1866 				unsigned int secs, bool gc_only)
1867 {
1868 	unsigned int segno, next_inuse, start, end;
1869 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1870 	int gc_mode, gc_type;
1871 	int err = 0;
1872 	int type;
1873 
1874 	/* Force block allocation for GC */
1875 	MAIN_SECS(sbi) -= secs;
1876 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1877 	end = MAIN_SEGS(sbi) - 1;
1878 
1879 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1880 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1881 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1882 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1883 
1884 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1885 		if (sbi->next_victim_seg[gc_type] >= start)
1886 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1887 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1888 
1889 	/* Move out cursegs from the target range */
1890 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++)
1891 		f2fs_allocate_segment_for_resize(sbi, type, start, end);
1892 
1893 	/* do GC to move out valid blocks in the range */
1894 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1895 		struct gc_inode_list gc_list = {
1896 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1897 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1898 		};
1899 
1900 		do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
1901 		put_gc_inode(&gc_list);
1902 
1903 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
1904 			err = -EAGAIN;
1905 			goto out;
1906 		}
1907 		if (fatal_signal_pending(current)) {
1908 			err = -ERESTARTSYS;
1909 			goto out;
1910 		}
1911 	}
1912 	if (gc_only)
1913 		goto out;
1914 
1915 	err = f2fs_write_checkpoint(sbi, &cpc);
1916 	if (err)
1917 		goto out;
1918 
1919 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1920 	if (next_inuse <= end) {
1921 		f2fs_err(sbi, "segno %u should be free but still inuse!",
1922 			 next_inuse);
1923 		f2fs_bug_on(sbi, 1);
1924 	}
1925 out:
1926 	MAIN_SECS(sbi) += secs;
1927 	return err;
1928 }
1929 
1930 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1931 {
1932 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1933 	int section_count;
1934 	int segment_count;
1935 	int segment_count_main;
1936 	long long block_count;
1937 	int segs = secs * sbi->segs_per_sec;
1938 
1939 	down_write(&sbi->sb_lock);
1940 
1941 	section_count = le32_to_cpu(raw_sb->section_count);
1942 	segment_count = le32_to_cpu(raw_sb->segment_count);
1943 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1944 	block_count = le64_to_cpu(raw_sb->block_count);
1945 
1946 	raw_sb->section_count = cpu_to_le32(section_count + secs);
1947 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1948 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1949 	raw_sb->block_count = cpu_to_le64(block_count +
1950 					(long long)segs * sbi->blocks_per_seg);
1951 	if (f2fs_is_multi_device(sbi)) {
1952 		int last_dev = sbi->s_ndevs - 1;
1953 		int dev_segs =
1954 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
1955 
1956 		raw_sb->devs[last_dev].total_segments =
1957 						cpu_to_le32(dev_segs + segs);
1958 	}
1959 
1960 	up_write(&sbi->sb_lock);
1961 }
1962 
1963 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1964 {
1965 	int segs = secs * sbi->segs_per_sec;
1966 	long long blks = (long long)segs * sbi->blocks_per_seg;
1967 	long long user_block_count =
1968 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1969 
1970 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1971 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1972 	MAIN_SECS(sbi) += secs;
1973 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1974 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1975 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
1976 
1977 	if (f2fs_is_multi_device(sbi)) {
1978 		int last_dev = sbi->s_ndevs - 1;
1979 
1980 		FDEV(last_dev).total_segments =
1981 				(int)FDEV(last_dev).total_segments + segs;
1982 		FDEV(last_dev).end_blk =
1983 				(long long)FDEV(last_dev).end_blk + blks;
1984 #ifdef CONFIG_BLK_DEV_ZONED
1985 		FDEV(last_dev).nr_blkz = (int)FDEV(last_dev).nr_blkz +
1986 					(int)(blks >> sbi->log_blocks_per_blkz);
1987 #endif
1988 	}
1989 }
1990 
1991 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1992 {
1993 	__u64 old_block_count, shrunk_blocks;
1994 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1995 	unsigned int secs;
1996 	int err = 0;
1997 	__u32 rem;
1998 
1999 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
2000 	if (block_count > old_block_count)
2001 		return -EINVAL;
2002 
2003 	if (f2fs_is_multi_device(sbi)) {
2004 		int last_dev = sbi->s_ndevs - 1;
2005 		__u64 last_segs = FDEV(last_dev).total_segments;
2006 
2007 		if (block_count + last_segs * sbi->blocks_per_seg <=
2008 								old_block_count)
2009 			return -EINVAL;
2010 	}
2011 
2012 	/* new fs size should align to section size */
2013 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
2014 	if (rem)
2015 		return -EINVAL;
2016 
2017 	if (block_count == old_block_count)
2018 		return 0;
2019 
2020 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
2021 		f2fs_err(sbi, "Should run fsck to repair first.");
2022 		return -EFSCORRUPTED;
2023 	}
2024 
2025 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2026 		f2fs_err(sbi, "Checkpoint should be enabled.");
2027 		return -EINVAL;
2028 	}
2029 
2030 	shrunk_blocks = old_block_count - block_count;
2031 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2032 
2033 	/* stop other GC */
2034 	if (!down_write_trylock(&sbi->gc_lock))
2035 		return -EAGAIN;
2036 
2037 	/* stop CP to protect MAIN_SEC in free_segment_range */
2038 	f2fs_lock_op(sbi);
2039 
2040 	spin_lock(&sbi->stat_lock);
2041 	if (shrunk_blocks + valid_user_blocks(sbi) +
2042 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2043 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2044 		err = -ENOSPC;
2045 	spin_unlock(&sbi->stat_lock);
2046 
2047 	if (err)
2048 		goto out_unlock;
2049 
2050 	err = free_segment_range(sbi, secs, true);
2051 
2052 out_unlock:
2053 	f2fs_unlock_op(sbi);
2054 	up_write(&sbi->gc_lock);
2055 	if (err)
2056 		return err;
2057 
2058 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2059 
2060 	freeze_super(sbi->sb);
2061 	down_write(&sbi->gc_lock);
2062 	down_write(&sbi->cp_global_sem);
2063 
2064 	spin_lock(&sbi->stat_lock);
2065 	if (shrunk_blocks + valid_user_blocks(sbi) +
2066 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2067 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2068 		err = -ENOSPC;
2069 	else
2070 		sbi->user_block_count -= shrunk_blocks;
2071 	spin_unlock(&sbi->stat_lock);
2072 	if (err)
2073 		goto out_err;
2074 
2075 	err = free_segment_range(sbi, secs, false);
2076 	if (err)
2077 		goto recover_out;
2078 
2079 	update_sb_metadata(sbi, -secs);
2080 
2081 	err = f2fs_commit_super(sbi, false);
2082 	if (err) {
2083 		update_sb_metadata(sbi, secs);
2084 		goto recover_out;
2085 	}
2086 
2087 	update_fs_metadata(sbi, -secs);
2088 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2089 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2090 
2091 	err = f2fs_write_checkpoint(sbi, &cpc);
2092 	if (err) {
2093 		update_fs_metadata(sbi, secs);
2094 		update_sb_metadata(sbi, secs);
2095 		f2fs_commit_super(sbi, false);
2096 	}
2097 recover_out:
2098 	if (err) {
2099 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2100 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2101 
2102 		spin_lock(&sbi->stat_lock);
2103 		sbi->user_block_count += shrunk_blocks;
2104 		spin_unlock(&sbi->stat_lock);
2105 	}
2106 out_err:
2107 	up_write(&sbi->cp_global_sem);
2108 	up_write(&sbi->gc_lock);
2109 	thaw_super(sbi->sb);
2110 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2111 	return err;
2112 }
2113