xref: /openbmc/linux/fs/f2fs/gc.c (revision cb1aaebe)
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/backing-dev.h>
11 #include <linux/init.h>
12 #include <linux/f2fs_fs.h>
13 #include <linux/kthread.h>
14 #include <linux/delay.h>
15 #include <linux/freezer.h>
16 
17 #include "f2fs.h"
18 #include "node.h"
19 #include "segment.h"
20 #include "gc.h"
21 #include <trace/events/f2fs.h>
22 
23 static int gc_thread_func(void *data)
24 {
25 	struct f2fs_sb_info *sbi = data;
26 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
27 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
28 	unsigned int wait_ms;
29 
30 	wait_ms = gc_th->min_sleep_time;
31 
32 	set_freezable();
33 	do {
34 		wait_event_interruptible_timeout(*wq,
35 				kthread_should_stop() || freezing(current) ||
36 				gc_th->gc_wake,
37 				msecs_to_jiffies(wait_ms));
38 
39 		/* give it a try one time */
40 		if (gc_th->gc_wake)
41 			gc_th->gc_wake = 0;
42 
43 		if (try_to_freeze()) {
44 			stat_other_skip_bggc_count(sbi);
45 			continue;
46 		}
47 		if (kthread_should_stop())
48 			break;
49 
50 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
51 			increase_sleep_time(gc_th, &wait_ms);
52 			stat_other_skip_bggc_count(sbi);
53 			continue;
54 		}
55 
56 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
57 			f2fs_show_injection_info(FAULT_CHECKPOINT);
58 			f2fs_stop_checkpoint(sbi, false);
59 		}
60 
61 		if (!sb_start_write_trylock(sbi->sb)) {
62 			stat_other_skip_bggc_count(sbi);
63 			continue;
64 		}
65 
66 		/*
67 		 * [GC triggering condition]
68 		 * 0. GC is not conducted currently.
69 		 * 1. There are enough dirty segments.
70 		 * 2. IO subsystem is idle by checking the # of writeback pages.
71 		 * 3. IO subsystem is idle by checking the # of requests in
72 		 *    bdev's request list.
73 		 *
74 		 * Note) We have to avoid triggering GCs frequently.
75 		 * Because it is possible that some segments can be
76 		 * invalidated soon after by user update or deletion.
77 		 * So, I'd like to wait some time to collect dirty segments.
78 		 */
79 		if (sbi->gc_mode == GC_URGENT) {
80 			wait_ms = gc_th->urgent_sleep_time;
81 			mutex_lock(&sbi->gc_mutex);
82 			goto do_gc;
83 		}
84 
85 		if (!mutex_trylock(&sbi->gc_mutex)) {
86 			stat_other_skip_bggc_count(sbi);
87 			goto next;
88 		}
89 
90 		if (!is_idle(sbi, GC_TIME)) {
91 			increase_sleep_time(gc_th, &wait_ms);
92 			mutex_unlock(&sbi->gc_mutex);
93 			stat_io_skip_bggc_count(sbi);
94 			goto next;
95 		}
96 
97 		if (has_enough_invalid_blocks(sbi))
98 			decrease_sleep_time(gc_th, &wait_ms);
99 		else
100 			increase_sleep_time(gc_th, &wait_ms);
101 do_gc:
102 		stat_inc_bggc_count(sbi);
103 
104 		/* if return value is not zero, no victim was selected */
105 		if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true, NULL_SEGNO))
106 			wait_ms = gc_th->no_gc_sleep_time;
107 
108 		trace_f2fs_background_gc(sbi->sb, wait_ms,
109 				prefree_segments(sbi), free_segments(sbi));
110 
111 		/* balancing f2fs's metadata periodically */
112 		f2fs_balance_fs_bg(sbi);
113 next:
114 		sb_end_write(sbi->sb);
115 
116 	} while (!kthread_should_stop());
117 	return 0;
118 }
119 
120 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
121 {
122 	struct f2fs_gc_kthread *gc_th;
123 	dev_t dev = sbi->sb->s_bdev->bd_dev;
124 	int err = 0;
125 
126 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
127 	if (!gc_th) {
128 		err = -ENOMEM;
129 		goto out;
130 	}
131 
132 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
133 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
134 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
135 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
136 
137 	gc_th->gc_wake= 0;
138 
139 	sbi->gc_thread = gc_th;
140 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
141 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
142 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
143 	if (IS_ERR(gc_th->f2fs_gc_task)) {
144 		err = PTR_ERR(gc_th->f2fs_gc_task);
145 		kvfree(gc_th);
146 		sbi->gc_thread = NULL;
147 	}
148 out:
149 	return err;
150 }
151 
152 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
153 {
154 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
155 	if (!gc_th)
156 		return;
157 	kthread_stop(gc_th->f2fs_gc_task);
158 	kvfree(gc_th);
159 	sbi->gc_thread = NULL;
160 }
161 
162 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
163 {
164 	int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
165 
166 	switch (sbi->gc_mode) {
167 	case GC_IDLE_CB:
168 		gc_mode = GC_CB;
169 		break;
170 	case GC_IDLE_GREEDY:
171 	case GC_URGENT:
172 		gc_mode = GC_GREEDY;
173 		break;
174 	}
175 	return gc_mode;
176 }
177 
178 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
179 			int type, struct victim_sel_policy *p)
180 {
181 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
182 
183 	if (p->alloc_mode == SSR) {
184 		p->gc_mode = GC_GREEDY;
185 		p->dirty_segmap = dirty_i->dirty_segmap[type];
186 		p->max_search = dirty_i->nr_dirty[type];
187 		p->ofs_unit = 1;
188 	} else {
189 		p->gc_mode = select_gc_type(sbi, gc_type);
190 		p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
191 		p->max_search = dirty_i->nr_dirty[DIRTY];
192 		p->ofs_unit = sbi->segs_per_sec;
193 	}
194 
195 	/* we need to check every dirty segments in the FG_GC case */
196 	if (gc_type != FG_GC &&
197 			(sbi->gc_mode != GC_URGENT) &&
198 			p->max_search > sbi->max_victim_search)
199 		p->max_search = sbi->max_victim_search;
200 
201 	/* let's select beginning hot/small space first in no_heap mode*/
202 	if (test_opt(sbi, NOHEAP) &&
203 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
204 		p->offset = 0;
205 	else
206 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
207 }
208 
209 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
210 				struct victim_sel_policy *p)
211 {
212 	/* SSR allocates in a segment unit */
213 	if (p->alloc_mode == SSR)
214 		return sbi->blocks_per_seg;
215 	if (p->gc_mode == GC_GREEDY)
216 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
217 	else if (p->gc_mode == GC_CB)
218 		return UINT_MAX;
219 	else /* No other gc_mode */
220 		return 0;
221 }
222 
223 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
224 {
225 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
226 	unsigned int secno;
227 
228 	/*
229 	 * If the gc_type is FG_GC, we can select victim segments
230 	 * selected by background GC before.
231 	 * Those segments guarantee they have small valid blocks.
232 	 */
233 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
234 		if (sec_usage_check(sbi, secno))
235 			continue;
236 		clear_bit(secno, dirty_i->victim_secmap);
237 		return GET_SEG_FROM_SEC(sbi, secno);
238 	}
239 	return NULL_SEGNO;
240 }
241 
242 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
243 {
244 	struct sit_info *sit_i = SIT_I(sbi);
245 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
246 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
247 	unsigned long long mtime = 0;
248 	unsigned int vblocks;
249 	unsigned char age = 0;
250 	unsigned char u;
251 	unsigned int i;
252 
253 	for (i = 0; i < sbi->segs_per_sec; i++)
254 		mtime += get_seg_entry(sbi, start + i)->mtime;
255 	vblocks = get_valid_blocks(sbi, segno, true);
256 
257 	mtime = div_u64(mtime, sbi->segs_per_sec);
258 	vblocks = div_u64(vblocks, sbi->segs_per_sec);
259 
260 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
261 
262 	/* Handle if the system time has changed by the user */
263 	if (mtime < sit_i->min_mtime)
264 		sit_i->min_mtime = mtime;
265 	if (mtime > sit_i->max_mtime)
266 		sit_i->max_mtime = mtime;
267 	if (sit_i->max_mtime != sit_i->min_mtime)
268 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
269 				sit_i->max_mtime - sit_i->min_mtime);
270 
271 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
272 }
273 
274 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
275 			unsigned int segno, struct victim_sel_policy *p)
276 {
277 	if (p->alloc_mode == SSR)
278 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
279 
280 	/* alloc_mode == LFS */
281 	if (p->gc_mode == GC_GREEDY)
282 		return get_valid_blocks(sbi, segno, true);
283 	else
284 		return get_cb_cost(sbi, segno);
285 }
286 
287 static unsigned int count_bits(const unsigned long *addr,
288 				unsigned int offset, unsigned int len)
289 {
290 	unsigned int end = offset + len, sum = 0;
291 
292 	while (offset < end) {
293 		if (test_bit(offset++, addr))
294 			++sum;
295 	}
296 	return sum;
297 }
298 
299 /*
300  * This function is called from two paths.
301  * One is garbage collection and the other is SSR segment selection.
302  * When it is called during GC, it just gets a victim segment
303  * and it does not remove it from dirty seglist.
304  * When it is called from SSR segment selection, it finds a segment
305  * which has minimum valid blocks and removes it from dirty seglist.
306  */
307 static int get_victim_by_default(struct f2fs_sb_info *sbi,
308 		unsigned int *result, int gc_type, int type, char alloc_mode)
309 {
310 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
311 	struct sit_info *sm = SIT_I(sbi);
312 	struct victim_sel_policy p;
313 	unsigned int secno, last_victim;
314 	unsigned int last_segment = MAIN_SEGS(sbi);
315 	unsigned int nsearched = 0;
316 
317 	mutex_lock(&dirty_i->seglist_lock);
318 
319 	p.alloc_mode = alloc_mode;
320 	select_policy(sbi, gc_type, type, &p);
321 
322 	p.min_segno = NULL_SEGNO;
323 	p.min_cost = get_max_cost(sbi, &p);
324 
325 	if (*result != NULL_SEGNO) {
326 		if (get_valid_blocks(sbi, *result, false) &&
327 			!sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
328 			p.min_segno = *result;
329 		goto out;
330 	}
331 
332 	if (p.max_search == 0)
333 		goto out;
334 
335 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
336 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
337 			p.min_segno = sbi->next_victim_seg[BG_GC];
338 			*result = p.min_segno;
339 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
340 			goto got_result;
341 		}
342 		if (gc_type == FG_GC &&
343 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
344 			p.min_segno = sbi->next_victim_seg[FG_GC];
345 			*result = p.min_segno;
346 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
347 			goto got_result;
348 		}
349 	}
350 
351 	last_victim = sm->last_victim[p.gc_mode];
352 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
353 		p.min_segno = check_bg_victims(sbi);
354 		if (p.min_segno != NULL_SEGNO)
355 			goto got_it;
356 	}
357 
358 	while (1) {
359 		unsigned long cost;
360 		unsigned int segno;
361 
362 		segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
363 		if (segno >= last_segment) {
364 			if (sm->last_victim[p.gc_mode]) {
365 				last_segment =
366 					sm->last_victim[p.gc_mode];
367 				sm->last_victim[p.gc_mode] = 0;
368 				p.offset = 0;
369 				continue;
370 			}
371 			break;
372 		}
373 
374 		p.offset = segno + p.ofs_unit;
375 		if (p.ofs_unit > 1) {
376 			p.offset -= segno % p.ofs_unit;
377 			nsearched += count_bits(p.dirty_segmap,
378 						p.offset - p.ofs_unit,
379 						p.ofs_unit);
380 		} else {
381 			nsearched++;
382 		}
383 
384 		secno = GET_SEC_FROM_SEG(sbi, segno);
385 
386 		if (sec_usage_check(sbi, secno))
387 			goto next;
388 		/* Don't touch checkpointed data */
389 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
390 					get_ckpt_valid_blocks(sbi, segno)))
391 			goto next;
392 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
393 			goto next;
394 
395 		cost = get_gc_cost(sbi, segno, &p);
396 
397 		if (p.min_cost > cost) {
398 			p.min_segno = segno;
399 			p.min_cost = cost;
400 		}
401 next:
402 		if (nsearched >= p.max_search) {
403 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
404 				sm->last_victim[p.gc_mode] = last_victim + 1;
405 			else
406 				sm->last_victim[p.gc_mode] = segno + 1;
407 			sm->last_victim[p.gc_mode] %= MAIN_SEGS(sbi);
408 			break;
409 		}
410 	}
411 	if (p.min_segno != NULL_SEGNO) {
412 got_it:
413 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
414 got_result:
415 		if (p.alloc_mode == LFS) {
416 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
417 			if (gc_type == FG_GC)
418 				sbi->cur_victim_sec = secno;
419 			else
420 				set_bit(secno, dirty_i->victim_secmap);
421 		}
422 
423 	}
424 out:
425 	if (p.min_segno != NULL_SEGNO)
426 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
427 				sbi->cur_victim_sec,
428 				prefree_segments(sbi), free_segments(sbi));
429 	mutex_unlock(&dirty_i->seglist_lock);
430 
431 	return (p.min_segno == NULL_SEGNO) ? 0 : 1;
432 }
433 
434 static const struct victim_selection default_v_ops = {
435 	.get_victim = get_victim_by_default,
436 };
437 
438 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
439 {
440 	struct inode_entry *ie;
441 
442 	ie = radix_tree_lookup(&gc_list->iroot, ino);
443 	if (ie)
444 		return ie->inode;
445 	return NULL;
446 }
447 
448 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
449 {
450 	struct inode_entry *new_ie;
451 
452 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
453 		iput(inode);
454 		return;
455 	}
456 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
457 	new_ie->inode = inode;
458 
459 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
460 	list_add_tail(&new_ie->list, &gc_list->ilist);
461 }
462 
463 static void put_gc_inode(struct gc_inode_list *gc_list)
464 {
465 	struct inode_entry *ie, *next_ie;
466 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
467 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
468 		iput(ie->inode);
469 		list_del(&ie->list);
470 		kmem_cache_free(f2fs_inode_entry_slab, ie);
471 	}
472 }
473 
474 static int check_valid_map(struct f2fs_sb_info *sbi,
475 				unsigned int segno, int offset)
476 {
477 	struct sit_info *sit_i = SIT_I(sbi);
478 	struct seg_entry *sentry;
479 	int ret;
480 
481 	down_read(&sit_i->sentry_lock);
482 	sentry = get_seg_entry(sbi, segno);
483 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
484 	up_read(&sit_i->sentry_lock);
485 	return ret;
486 }
487 
488 /*
489  * This function compares node address got in summary with that in NAT.
490  * On validity, copy that node with cold status, otherwise (invalid node)
491  * ignore that.
492  */
493 static int gc_node_segment(struct f2fs_sb_info *sbi,
494 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
495 {
496 	struct f2fs_summary *entry;
497 	block_t start_addr;
498 	int off;
499 	int phase = 0;
500 	bool fggc = (gc_type == FG_GC);
501 	int submitted = 0;
502 
503 	start_addr = START_BLOCK(sbi, segno);
504 
505 next_step:
506 	entry = sum;
507 
508 	if (fggc && phase == 2)
509 		atomic_inc(&sbi->wb_sync_req[NODE]);
510 
511 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
512 		nid_t nid = le32_to_cpu(entry->nid);
513 		struct page *node_page;
514 		struct node_info ni;
515 		int err;
516 
517 		/* stop BG_GC if there is not enough free sections. */
518 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
519 			return submitted;
520 
521 		if (check_valid_map(sbi, segno, off) == 0)
522 			continue;
523 
524 		if (phase == 0) {
525 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
526 							META_NAT, true);
527 			continue;
528 		}
529 
530 		if (phase == 1) {
531 			f2fs_ra_node_page(sbi, nid);
532 			continue;
533 		}
534 
535 		/* phase == 2 */
536 		node_page = f2fs_get_node_page(sbi, nid);
537 		if (IS_ERR(node_page))
538 			continue;
539 
540 		/* block may become invalid during f2fs_get_node_page */
541 		if (check_valid_map(sbi, segno, off) == 0) {
542 			f2fs_put_page(node_page, 1);
543 			continue;
544 		}
545 
546 		if (f2fs_get_node_info(sbi, nid, &ni)) {
547 			f2fs_put_page(node_page, 1);
548 			continue;
549 		}
550 
551 		if (ni.blk_addr != start_addr + off) {
552 			f2fs_put_page(node_page, 1);
553 			continue;
554 		}
555 
556 		err = f2fs_move_node_page(node_page, gc_type);
557 		if (!err && gc_type == FG_GC)
558 			submitted++;
559 		stat_inc_node_blk_count(sbi, 1, gc_type);
560 	}
561 
562 	if (++phase < 3)
563 		goto next_step;
564 
565 	if (fggc)
566 		atomic_dec(&sbi->wb_sync_req[NODE]);
567 	return submitted;
568 }
569 
570 /*
571  * Calculate start block index indicating the given node offset.
572  * Be careful, caller should give this node offset only indicating direct node
573  * blocks. If any node offsets, which point the other types of node blocks such
574  * as indirect or double indirect node blocks, are given, it must be a caller's
575  * bug.
576  */
577 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
578 {
579 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
580 	unsigned int bidx;
581 
582 	if (node_ofs == 0)
583 		return 0;
584 
585 	if (node_ofs <= 2) {
586 		bidx = node_ofs - 1;
587 	} else if (node_ofs <= indirect_blks) {
588 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
589 		bidx = node_ofs - 2 - dec;
590 	} else {
591 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
592 		bidx = node_ofs - 5 - dec;
593 	}
594 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
595 }
596 
597 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
598 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
599 {
600 	struct page *node_page;
601 	nid_t nid;
602 	unsigned int ofs_in_node;
603 	block_t source_blkaddr;
604 
605 	nid = le32_to_cpu(sum->nid);
606 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
607 
608 	node_page = f2fs_get_node_page(sbi, nid);
609 	if (IS_ERR(node_page))
610 		return false;
611 
612 	if (f2fs_get_node_info(sbi, nid, dni)) {
613 		f2fs_put_page(node_page, 1);
614 		return false;
615 	}
616 
617 	if (sum->version != dni->version) {
618 		f2fs_msg(sbi->sb, KERN_WARNING,
619 				"%s: valid data with mismatched node version.",
620 				__func__);
621 		set_sbi_flag(sbi, SBI_NEED_FSCK);
622 	}
623 
624 	*nofs = ofs_of_node(node_page);
625 	source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
626 	f2fs_put_page(node_page, 1);
627 
628 	if (source_blkaddr != blkaddr)
629 		return false;
630 	return true;
631 }
632 
633 static int ra_data_block(struct inode *inode, pgoff_t index)
634 {
635 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
636 	struct address_space *mapping = inode->i_mapping;
637 	struct dnode_of_data dn;
638 	struct page *page;
639 	struct extent_info ei = {0, 0, 0};
640 	struct f2fs_io_info fio = {
641 		.sbi = sbi,
642 		.ino = inode->i_ino,
643 		.type = DATA,
644 		.temp = COLD,
645 		.op = REQ_OP_READ,
646 		.op_flags = 0,
647 		.encrypted_page = NULL,
648 		.in_list = false,
649 		.retry = false,
650 	};
651 	int err;
652 
653 	page = f2fs_grab_cache_page(mapping, index, true);
654 	if (!page)
655 		return -ENOMEM;
656 
657 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
658 		dn.data_blkaddr = ei.blk + index - ei.fofs;
659 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
660 						DATA_GENERIC_ENHANCE_READ))) {
661 			err = -EFAULT;
662 			goto put_page;
663 		}
664 		goto got_it;
665 	}
666 
667 	set_new_dnode(&dn, inode, NULL, NULL, 0);
668 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
669 	if (err)
670 		goto put_page;
671 	f2fs_put_dnode(&dn);
672 
673 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
674 		err = -ENOENT;
675 		goto put_page;
676 	}
677 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
678 						DATA_GENERIC_ENHANCE))) {
679 		err = -EFAULT;
680 		goto put_page;
681 	}
682 got_it:
683 	/* read page */
684 	fio.page = page;
685 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
686 
687 	/*
688 	 * don't cache encrypted data into meta inode until previous dirty
689 	 * data were writebacked to avoid racing between GC and flush.
690 	 */
691 	f2fs_wait_on_page_writeback(page, DATA, true, true);
692 
693 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
694 
695 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
696 					dn.data_blkaddr,
697 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
698 	if (!fio.encrypted_page) {
699 		err = -ENOMEM;
700 		goto put_page;
701 	}
702 
703 	err = f2fs_submit_page_bio(&fio);
704 	if (err)
705 		goto put_encrypted_page;
706 	f2fs_put_page(fio.encrypted_page, 0);
707 	f2fs_put_page(page, 1);
708 	return 0;
709 put_encrypted_page:
710 	f2fs_put_page(fio.encrypted_page, 1);
711 put_page:
712 	f2fs_put_page(page, 1);
713 	return err;
714 }
715 
716 /*
717  * Move data block via META_MAPPING while keeping locked data page.
718  * This can be used to move blocks, aka LBAs, directly on disk.
719  */
720 static int move_data_block(struct inode *inode, block_t bidx,
721 				int gc_type, unsigned int segno, int off)
722 {
723 	struct f2fs_io_info fio = {
724 		.sbi = F2FS_I_SB(inode),
725 		.ino = inode->i_ino,
726 		.type = DATA,
727 		.temp = COLD,
728 		.op = REQ_OP_READ,
729 		.op_flags = 0,
730 		.encrypted_page = NULL,
731 		.in_list = false,
732 		.retry = false,
733 	};
734 	struct dnode_of_data dn;
735 	struct f2fs_summary sum;
736 	struct node_info ni;
737 	struct page *page, *mpage;
738 	block_t newaddr;
739 	int err = 0;
740 	bool lfs_mode = test_opt(fio.sbi, LFS);
741 
742 	/* do not read out */
743 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
744 	if (!page)
745 		return -ENOMEM;
746 
747 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
748 		err = -ENOENT;
749 		goto out;
750 	}
751 
752 	if (f2fs_is_atomic_file(inode)) {
753 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
754 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
755 		err = -EAGAIN;
756 		goto out;
757 	}
758 
759 	if (f2fs_is_pinned_file(inode)) {
760 		f2fs_pin_file_control(inode, true);
761 		err = -EAGAIN;
762 		goto out;
763 	}
764 
765 	set_new_dnode(&dn, inode, NULL, NULL, 0);
766 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
767 	if (err)
768 		goto out;
769 
770 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
771 		ClearPageUptodate(page);
772 		err = -ENOENT;
773 		goto put_out;
774 	}
775 
776 	/*
777 	 * don't cache encrypted data into meta inode until previous dirty
778 	 * data were writebacked to avoid racing between GC and flush.
779 	 */
780 	f2fs_wait_on_page_writeback(page, DATA, true, true);
781 
782 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
783 
784 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
785 	if (err)
786 		goto put_out;
787 
788 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
789 
790 	/* read page */
791 	fio.page = page;
792 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
793 
794 	if (lfs_mode)
795 		down_write(&fio.sbi->io_order_lock);
796 
797 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
798 					&sum, CURSEG_COLD_DATA, NULL, false);
799 
800 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
801 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
802 	if (!fio.encrypted_page) {
803 		err = -ENOMEM;
804 		goto recover_block;
805 	}
806 
807 	mpage = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
808 					fio.old_blkaddr, FGP_LOCK, GFP_NOFS);
809 	if (mpage) {
810 		bool updated = false;
811 
812 		if (PageUptodate(mpage)) {
813 			memcpy(page_address(fio.encrypted_page),
814 					page_address(mpage), PAGE_SIZE);
815 			updated = true;
816 		}
817 		f2fs_put_page(mpage, 1);
818 		invalidate_mapping_pages(META_MAPPING(fio.sbi),
819 					fio.old_blkaddr, fio.old_blkaddr);
820 		if (updated)
821 			goto write_page;
822 	}
823 
824 	err = f2fs_submit_page_bio(&fio);
825 	if (err)
826 		goto put_page_out;
827 
828 	/* write page */
829 	lock_page(fio.encrypted_page);
830 
831 	if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
832 		err = -EIO;
833 		goto put_page_out;
834 	}
835 	if (unlikely(!PageUptodate(fio.encrypted_page))) {
836 		err = -EIO;
837 		goto put_page_out;
838 	}
839 
840 write_page:
841 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
842 	set_page_dirty(fio.encrypted_page);
843 	if (clear_page_dirty_for_io(fio.encrypted_page))
844 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
845 
846 	set_page_writeback(fio.encrypted_page);
847 	ClearPageError(page);
848 
849 	/* allocate block address */
850 	f2fs_wait_on_page_writeback(dn.node_page, NODE, true, true);
851 
852 	fio.op = REQ_OP_WRITE;
853 	fio.op_flags = REQ_SYNC;
854 	fio.new_blkaddr = newaddr;
855 	f2fs_submit_page_write(&fio);
856 	if (fio.retry) {
857 		err = -EAGAIN;
858 		if (PageWriteback(fio.encrypted_page))
859 			end_page_writeback(fio.encrypted_page);
860 		goto put_page_out;
861 	}
862 
863 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
864 
865 	f2fs_update_data_blkaddr(&dn, newaddr);
866 	set_inode_flag(inode, FI_APPEND_WRITE);
867 	if (page->index == 0)
868 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
869 put_page_out:
870 	f2fs_put_page(fio.encrypted_page, 1);
871 recover_block:
872 	if (lfs_mode)
873 		up_write(&fio.sbi->io_order_lock);
874 	if (err)
875 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
876 								true, true);
877 put_out:
878 	f2fs_put_dnode(&dn);
879 out:
880 	f2fs_put_page(page, 1);
881 	return err;
882 }
883 
884 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
885 							unsigned int segno, int off)
886 {
887 	struct page *page;
888 	int err = 0;
889 
890 	page = f2fs_get_lock_data_page(inode, bidx, true);
891 	if (IS_ERR(page))
892 		return PTR_ERR(page);
893 
894 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
895 		err = -ENOENT;
896 		goto out;
897 	}
898 
899 	if (f2fs_is_atomic_file(inode)) {
900 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
901 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
902 		err = -EAGAIN;
903 		goto out;
904 	}
905 	if (f2fs_is_pinned_file(inode)) {
906 		if (gc_type == FG_GC)
907 			f2fs_pin_file_control(inode, true);
908 		err = -EAGAIN;
909 		goto out;
910 	}
911 
912 	if (gc_type == BG_GC) {
913 		if (PageWriteback(page)) {
914 			err = -EAGAIN;
915 			goto out;
916 		}
917 		set_page_dirty(page);
918 		set_cold_data(page);
919 	} else {
920 		struct f2fs_io_info fio = {
921 			.sbi = F2FS_I_SB(inode),
922 			.ino = inode->i_ino,
923 			.type = DATA,
924 			.temp = COLD,
925 			.op = REQ_OP_WRITE,
926 			.op_flags = REQ_SYNC,
927 			.old_blkaddr = NULL_ADDR,
928 			.page = page,
929 			.encrypted_page = NULL,
930 			.need_lock = LOCK_REQ,
931 			.io_type = FS_GC_DATA_IO,
932 		};
933 		bool is_dirty = PageDirty(page);
934 
935 retry:
936 		f2fs_wait_on_page_writeback(page, DATA, true, true);
937 
938 		set_page_dirty(page);
939 		if (clear_page_dirty_for_io(page)) {
940 			inode_dec_dirty_pages(inode);
941 			f2fs_remove_dirty_inode(inode);
942 		}
943 
944 		set_cold_data(page);
945 
946 		err = f2fs_do_write_data_page(&fio);
947 		if (err) {
948 			clear_cold_data(page);
949 			if (err == -ENOMEM) {
950 				congestion_wait(BLK_RW_ASYNC, HZ/50);
951 				goto retry;
952 			}
953 			if (is_dirty)
954 				set_page_dirty(page);
955 		}
956 	}
957 out:
958 	f2fs_put_page(page, 1);
959 	return err;
960 }
961 
962 /*
963  * This function tries to get parent node of victim data block, and identifies
964  * data block validity. If the block is valid, copy that with cold status and
965  * modify parent node.
966  * If the parent node is not valid or the data block address is different,
967  * the victim data block is ignored.
968  */
969 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
970 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
971 {
972 	struct super_block *sb = sbi->sb;
973 	struct f2fs_summary *entry;
974 	block_t start_addr;
975 	int off;
976 	int phase = 0;
977 	int submitted = 0;
978 
979 	start_addr = START_BLOCK(sbi, segno);
980 
981 next_step:
982 	entry = sum;
983 
984 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
985 		struct page *data_page;
986 		struct inode *inode;
987 		struct node_info dni; /* dnode info for the data */
988 		unsigned int ofs_in_node, nofs;
989 		block_t start_bidx;
990 		nid_t nid = le32_to_cpu(entry->nid);
991 
992 		/* stop BG_GC if there is not enough free sections. */
993 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
994 			return submitted;
995 
996 		if (check_valid_map(sbi, segno, off) == 0)
997 			continue;
998 
999 		if (phase == 0) {
1000 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1001 							META_NAT, true);
1002 			continue;
1003 		}
1004 
1005 		if (phase == 1) {
1006 			f2fs_ra_node_page(sbi, nid);
1007 			continue;
1008 		}
1009 
1010 		/* Get an inode by ino with checking validity */
1011 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1012 			continue;
1013 
1014 		if (phase == 2) {
1015 			f2fs_ra_node_page(sbi, dni.ino);
1016 			continue;
1017 		}
1018 
1019 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1020 
1021 		if (phase == 3) {
1022 			inode = f2fs_iget(sb, dni.ino);
1023 			if (IS_ERR(inode) || is_bad_inode(inode))
1024 				continue;
1025 
1026 			if (!down_write_trylock(
1027 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1028 				iput(inode);
1029 				sbi->skipped_gc_rwsem++;
1030 				continue;
1031 			}
1032 
1033 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1034 								ofs_in_node;
1035 
1036 			if (f2fs_post_read_required(inode)) {
1037 				int err = ra_data_block(inode, start_bidx);
1038 
1039 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1040 				if (err) {
1041 					iput(inode);
1042 					continue;
1043 				}
1044 				add_gc_inode(gc_list, inode);
1045 				continue;
1046 			}
1047 
1048 			data_page = f2fs_get_read_data_page(inode,
1049 						start_bidx, REQ_RAHEAD, true);
1050 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1051 			if (IS_ERR(data_page)) {
1052 				iput(inode);
1053 				continue;
1054 			}
1055 
1056 			f2fs_put_page(data_page, 0);
1057 			add_gc_inode(gc_list, inode);
1058 			continue;
1059 		}
1060 
1061 		/* phase 4 */
1062 		inode = find_gc_inode(gc_list, dni.ino);
1063 		if (inode) {
1064 			struct f2fs_inode_info *fi = F2FS_I(inode);
1065 			bool locked = false;
1066 			int err;
1067 
1068 			if (S_ISREG(inode->i_mode)) {
1069 				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1070 					continue;
1071 				if (!down_write_trylock(
1072 						&fi->i_gc_rwsem[WRITE])) {
1073 					sbi->skipped_gc_rwsem++;
1074 					up_write(&fi->i_gc_rwsem[READ]);
1075 					continue;
1076 				}
1077 				locked = true;
1078 
1079 				/* wait for all inflight aio data */
1080 				inode_dio_wait(inode);
1081 			}
1082 
1083 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1084 								+ ofs_in_node;
1085 			if (f2fs_post_read_required(inode))
1086 				err = move_data_block(inode, start_bidx,
1087 							gc_type, segno, off);
1088 			else
1089 				err = move_data_page(inode, start_bidx, gc_type,
1090 								segno, off);
1091 
1092 			if (!err && (gc_type == FG_GC ||
1093 					f2fs_post_read_required(inode)))
1094 				submitted++;
1095 
1096 			if (locked) {
1097 				up_write(&fi->i_gc_rwsem[WRITE]);
1098 				up_write(&fi->i_gc_rwsem[READ]);
1099 			}
1100 
1101 			stat_inc_data_blk_count(sbi, 1, gc_type);
1102 		}
1103 	}
1104 
1105 	if (++phase < 5)
1106 		goto next_step;
1107 
1108 	return submitted;
1109 }
1110 
1111 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1112 			int gc_type)
1113 {
1114 	struct sit_info *sit_i = SIT_I(sbi);
1115 	int ret;
1116 
1117 	down_write(&sit_i->sentry_lock);
1118 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1119 					      NO_CHECK_TYPE, LFS);
1120 	up_write(&sit_i->sentry_lock);
1121 	return ret;
1122 }
1123 
1124 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1125 				unsigned int start_segno,
1126 				struct gc_inode_list *gc_list, int gc_type)
1127 {
1128 	struct page *sum_page;
1129 	struct f2fs_summary_block *sum;
1130 	struct blk_plug plug;
1131 	unsigned int segno = start_segno;
1132 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1133 	int seg_freed = 0, migrated = 0;
1134 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1135 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1136 	int submitted = 0;
1137 
1138 	if (__is_large_section(sbi))
1139 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1140 
1141 	/* readahead multi ssa blocks those have contiguous address */
1142 	if (__is_large_section(sbi))
1143 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1144 					end_segno - segno, META_SSA, true);
1145 
1146 	/* reference all summary page */
1147 	while (segno < end_segno) {
1148 		sum_page = f2fs_get_sum_page(sbi, segno++);
1149 		if (IS_ERR(sum_page)) {
1150 			int err = PTR_ERR(sum_page);
1151 
1152 			end_segno = segno - 1;
1153 			for (segno = start_segno; segno < end_segno; segno++) {
1154 				sum_page = find_get_page(META_MAPPING(sbi),
1155 						GET_SUM_BLOCK(sbi, segno));
1156 				f2fs_put_page(sum_page, 0);
1157 				f2fs_put_page(sum_page, 0);
1158 			}
1159 			return err;
1160 		}
1161 		unlock_page(sum_page);
1162 	}
1163 
1164 	blk_start_plug(&plug);
1165 
1166 	for (segno = start_segno; segno < end_segno; segno++) {
1167 
1168 		/* find segment summary of victim */
1169 		sum_page = find_get_page(META_MAPPING(sbi),
1170 					GET_SUM_BLOCK(sbi, segno));
1171 		f2fs_put_page(sum_page, 0);
1172 
1173 		if (get_valid_blocks(sbi, segno, false) == 0)
1174 			goto freed;
1175 		if (__is_large_section(sbi) &&
1176 				migrated >= sbi->migration_granularity)
1177 			goto skip;
1178 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1179 			goto skip;
1180 
1181 		sum = page_address(sum_page);
1182 		if (type != GET_SUM_TYPE((&sum->footer))) {
1183 			f2fs_msg(sbi->sb, KERN_ERR, "Inconsistent segment (%u) "
1184 				"type [%d, %d] in SSA and SIT",
1185 				segno, type, GET_SUM_TYPE((&sum->footer)));
1186 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1187 			f2fs_stop_checkpoint(sbi, false);
1188 			goto skip;
1189 		}
1190 
1191 		/*
1192 		 * this is to avoid deadlock:
1193 		 * - lock_page(sum_page)         - f2fs_replace_block
1194 		 *  - check_valid_map()            - down_write(sentry_lock)
1195 		 *   - down_read(sentry_lock)     - change_curseg()
1196 		 *                                  - lock_page(sum_page)
1197 		 */
1198 		if (type == SUM_TYPE_NODE)
1199 			submitted += gc_node_segment(sbi, sum->entries, segno,
1200 								gc_type);
1201 		else
1202 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1203 							segno, gc_type);
1204 
1205 		stat_inc_seg_count(sbi, type, gc_type);
1206 
1207 freed:
1208 		if (gc_type == FG_GC &&
1209 				get_valid_blocks(sbi, segno, false) == 0)
1210 			seg_freed++;
1211 		migrated++;
1212 
1213 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1214 			sbi->next_victim_seg[gc_type] = segno + 1;
1215 skip:
1216 		f2fs_put_page(sum_page, 0);
1217 	}
1218 
1219 	if (submitted)
1220 		f2fs_submit_merged_write(sbi,
1221 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1222 
1223 	blk_finish_plug(&plug);
1224 
1225 	stat_inc_call_count(sbi->stat_info);
1226 
1227 	return seg_freed;
1228 }
1229 
1230 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1231 			bool background, unsigned int segno)
1232 {
1233 	int gc_type = sync ? FG_GC : BG_GC;
1234 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1235 	int ret = 0;
1236 	struct cp_control cpc;
1237 	unsigned int init_segno = segno;
1238 	struct gc_inode_list gc_list = {
1239 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1240 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1241 	};
1242 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1243 	unsigned long long first_skipped;
1244 	unsigned int skipped_round = 0, round = 0;
1245 
1246 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1247 				get_pages(sbi, F2FS_DIRTY_NODES),
1248 				get_pages(sbi, F2FS_DIRTY_DENTS),
1249 				get_pages(sbi, F2FS_DIRTY_IMETA),
1250 				free_sections(sbi),
1251 				free_segments(sbi),
1252 				reserved_segments(sbi),
1253 				prefree_segments(sbi));
1254 
1255 	cpc.reason = __get_cp_reason(sbi);
1256 	sbi->skipped_gc_rwsem = 0;
1257 	first_skipped = last_skipped;
1258 gc_more:
1259 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1260 		ret = -EINVAL;
1261 		goto stop;
1262 	}
1263 	if (unlikely(f2fs_cp_error(sbi))) {
1264 		ret = -EIO;
1265 		goto stop;
1266 	}
1267 
1268 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1269 		/*
1270 		 * For example, if there are many prefree_segments below given
1271 		 * threshold, we can make them free by checkpoint. Then, we
1272 		 * secure free segments which doesn't need fggc any more.
1273 		 */
1274 		if (prefree_segments(sbi) &&
1275 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1276 			ret = f2fs_write_checkpoint(sbi, &cpc);
1277 			if (ret)
1278 				goto stop;
1279 		}
1280 		if (has_not_enough_free_secs(sbi, 0, 0))
1281 			gc_type = FG_GC;
1282 	}
1283 
1284 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1285 	if (gc_type == BG_GC && !background) {
1286 		ret = -EINVAL;
1287 		goto stop;
1288 	}
1289 	if (!__get_victim(sbi, &segno, gc_type)) {
1290 		ret = -ENODATA;
1291 		goto stop;
1292 	}
1293 
1294 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1295 	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1296 		sec_freed++;
1297 	total_freed += seg_freed;
1298 
1299 	if (gc_type == FG_GC) {
1300 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1301 						sbi->skipped_gc_rwsem)
1302 			skipped_round++;
1303 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1304 		round++;
1305 	}
1306 
1307 	if (gc_type == FG_GC)
1308 		sbi->cur_victim_sec = NULL_SEGNO;
1309 
1310 	if (sync)
1311 		goto stop;
1312 
1313 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1314 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1315 					skipped_round * 2 < round) {
1316 			segno = NULL_SEGNO;
1317 			goto gc_more;
1318 		}
1319 
1320 		if (first_skipped < last_skipped &&
1321 				(last_skipped - first_skipped) >
1322 						sbi->skipped_gc_rwsem) {
1323 			f2fs_drop_inmem_pages_all(sbi, true);
1324 			segno = NULL_SEGNO;
1325 			goto gc_more;
1326 		}
1327 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1328 			ret = f2fs_write_checkpoint(sbi, &cpc);
1329 	}
1330 stop:
1331 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1332 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1333 
1334 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1335 				get_pages(sbi, F2FS_DIRTY_NODES),
1336 				get_pages(sbi, F2FS_DIRTY_DENTS),
1337 				get_pages(sbi, F2FS_DIRTY_IMETA),
1338 				free_sections(sbi),
1339 				free_segments(sbi),
1340 				reserved_segments(sbi),
1341 				prefree_segments(sbi));
1342 
1343 	mutex_unlock(&sbi->gc_mutex);
1344 
1345 	put_gc_inode(&gc_list);
1346 
1347 	if (sync && !ret)
1348 		ret = sec_freed ? 0 : -EAGAIN;
1349 	return ret;
1350 }
1351 
1352 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1353 {
1354 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1355 
1356 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1357 
1358 	/* give warm/cold data area from slower device */
1359 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1360 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1361 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1362 }
1363