xref: /openbmc/linux/fs/f2fs/gc.c (revision ff7b437f)
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;
315 	unsigned int nsearched = 0;
316 
317 	mutex_lock(&dirty_i->seglist_lock);
318 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
319 
320 	p.alloc_mode = alloc_mode;
321 	select_policy(sbi, gc_type, type, &p);
322 
323 	p.min_segno = NULL_SEGNO;
324 	p.min_cost = get_max_cost(sbi, &p);
325 
326 	if (*result != NULL_SEGNO) {
327 		if (get_valid_blocks(sbi, *result, false) &&
328 			!sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
329 			p.min_segno = *result;
330 		goto out;
331 	}
332 
333 	if (p.max_search == 0)
334 		goto out;
335 
336 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
337 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
338 			p.min_segno = sbi->next_victim_seg[BG_GC];
339 			*result = p.min_segno;
340 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
341 			goto got_result;
342 		}
343 		if (gc_type == FG_GC &&
344 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
345 			p.min_segno = sbi->next_victim_seg[FG_GC];
346 			*result = p.min_segno;
347 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
348 			goto got_result;
349 		}
350 	}
351 
352 	last_victim = sm->last_victim[p.gc_mode];
353 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
354 		p.min_segno = check_bg_victims(sbi);
355 		if (p.min_segno != NULL_SEGNO)
356 			goto got_it;
357 	}
358 
359 	while (1) {
360 		unsigned long cost;
361 		unsigned int segno;
362 
363 		segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
364 		if (segno >= last_segment) {
365 			if (sm->last_victim[p.gc_mode]) {
366 				last_segment =
367 					sm->last_victim[p.gc_mode];
368 				sm->last_victim[p.gc_mode] = 0;
369 				p.offset = 0;
370 				continue;
371 			}
372 			break;
373 		}
374 
375 		p.offset = segno + p.ofs_unit;
376 		if (p.ofs_unit > 1) {
377 			p.offset -= segno % p.ofs_unit;
378 			nsearched += count_bits(p.dirty_segmap,
379 						p.offset - p.ofs_unit,
380 						p.ofs_unit);
381 		} else {
382 			nsearched++;
383 		}
384 
385 #ifdef CONFIG_F2FS_CHECK_FS
386 		/*
387 		 * skip selecting the invalid segno (that is failed due to block
388 		 * validity check failure during GC) to avoid endless GC loop in
389 		 * such cases.
390 		 */
391 		if (test_bit(segno, sm->invalid_segmap))
392 			goto next;
393 #endif
394 
395 		secno = GET_SEC_FROM_SEG(sbi, segno);
396 
397 		if (sec_usage_check(sbi, secno))
398 			goto next;
399 		/* Don't touch checkpointed data */
400 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
401 					get_ckpt_valid_blocks(sbi, segno) &&
402 					p.alloc_mode != SSR))
403 			goto next;
404 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
405 			goto next;
406 
407 		cost = get_gc_cost(sbi, segno, &p);
408 
409 		if (p.min_cost > cost) {
410 			p.min_segno = segno;
411 			p.min_cost = cost;
412 		}
413 next:
414 		if (nsearched >= p.max_search) {
415 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
416 				sm->last_victim[p.gc_mode] = last_victim + 1;
417 			else
418 				sm->last_victim[p.gc_mode] = segno + 1;
419 			sm->last_victim[p.gc_mode] %=
420 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
421 			break;
422 		}
423 	}
424 	if (p.min_segno != NULL_SEGNO) {
425 got_it:
426 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
427 got_result:
428 		if (p.alloc_mode == LFS) {
429 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
430 			if (gc_type == FG_GC)
431 				sbi->cur_victim_sec = secno;
432 			else
433 				set_bit(secno, dirty_i->victim_secmap);
434 		}
435 
436 	}
437 out:
438 	if (p.min_segno != NULL_SEGNO)
439 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
440 				sbi->cur_victim_sec,
441 				prefree_segments(sbi), free_segments(sbi));
442 	mutex_unlock(&dirty_i->seglist_lock);
443 
444 	return (p.min_segno == NULL_SEGNO) ? 0 : 1;
445 }
446 
447 static const struct victim_selection default_v_ops = {
448 	.get_victim = get_victim_by_default,
449 };
450 
451 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
452 {
453 	struct inode_entry *ie;
454 
455 	ie = radix_tree_lookup(&gc_list->iroot, ino);
456 	if (ie)
457 		return ie->inode;
458 	return NULL;
459 }
460 
461 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
462 {
463 	struct inode_entry *new_ie;
464 
465 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
466 		iput(inode);
467 		return;
468 	}
469 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
470 	new_ie->inode = inode;
471 
472 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
473 	list_add_tail(&new_ie->list, &gc_list->ilist);
474 }
475 
476 static void put_gc_inode(struct gc_inode_list *gc_list)
477 {
478 	struct inode_entry *ie, *next_ie;
479 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
480 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
481 		iput(ie->inode);
482 		list_del(&ie->list);
483 		kmem_cache_free(f2fs_inode_entry_slab, ie);
484 	}
485 }
486 
487 static int check_valid_map(struct f2fs_sb_info *sbi,
488 				unsigned int segno, int offset)
489 {
490 	struct sit_info *sit_i = SIT_I(sbi);
491 	struct seg_entry *sentry;
492 	int ret;
493 
494 	down_read(&sit_i->sentry_lock);
495 	sentry = get_seg_entry(sbi, segno);
496 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
497 	up_read(&sit_i->sentry_lock);
498 	return ret;
499 }
500 
501 /*
502  * This function compares node address got in summary with that in NAT.
503  * On validity, copy that node with cold status, otherwise (invalid node)
504  * ignore that.
505  */
506 static int gc_node_segment(struct f2fs_sb_info *sbi,
507 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
508 {
509 	struct f2fs_summary *entry;
510 	block_t start_addr;
511 	int off;
512 	int phase = 0;
513 	bool fggc = (gc_type == FG_GC);
514 	int submitted = 0;
515 
516 	start_addr = START_BLOCK(sbi, segno);
517 
518 next_step:
519 	entry = sum;
520 
521 	if (fggc && phase == 2)
522 		atomic_inc(&sbi->wb_sync_req[NODE]);
523 
524 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
525 		nid_t nid = le32_to_cpu(entry->nid);
526 		struct page *node_page;
527 		struct node_info ni;
528 		int err;
529 
530 		/* stop BG_GC if there is not enough free sections. */
531 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
532 			return submitted;
533 
534 		if (check_valid_map(sbi, segno, off) == 0)
535 			continue;
536 
537 		if (phase == 0) {
538 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
539 							META_NAT, true);
540 			continue;
541 		}
542 
543 		if (phase == 1) {
544 			f2fs_ra_node_page(sbi, nid);
545 			continue;
546 		}
547 
548 		/* phase == 2 */
549 		node_page = f2fs_get_node_page(sbi, nid);
550 		if (IS_ERR(node_page))
551 			continue;
552 
553 		/* block may become invalid during f2fs_get_node_page */
554 		if (check_valid_map(sbi, segno, off) == 0) {
555 			f2fs_put_page(node_page, 1);
556 			continue;
557 		}
558 
559 		if (f2fs_get_node_info(sbi, nid, &ni)) {
560 			f2fs_put_page(node_page, 1);
561 			continue;
562 		}
563 
564 		if (ni.blk_addr != start_addr + off) {
565 			f2fs_put_page(node_page, 1);
566 			continue;
567 		}
568 
569 		err = f2fs_move_node_page(node_page, gc_type);
570 		if (!err && gc_type == FG_GC)
571 			submitted++;
572 		stat_inc_node_blk_count(sbi, 1, gc_type);
573 	}
574 
575 	if (++phase < 3)
576 		goto next_step;
577 
578 	if (fggc)
579 		atomic_dec(&sbi->wb_sync_req[NODE]);
580 	return submitted;
581 }
582 
583 /*
584  * Calculate start block index indicating the given node offset.
585  * Be careful, caller should give this node offset only indicating direct node
586  * blocks. If any node offsets, which point the other types of node blocks such
587  * as indirect or double indirect node blocks, are given, it must be a caller's
588  * bug.
589  */
590 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
591 {
592 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
593 	unsigned int bidx;
594 
595 	if (node_ofs == 0)
596 		return 0;
597 
598 	if (node_ofs <= 2) {
599 		bidx = node_ofs - 1;
600 	} else if (node_ofs <= indirect_blks) {
601 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
602 		bidx = node_ofs - 2 - dec;
603 	} else {
604 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
605 		bidx = node_ofs - 5 - dec;
606 	}
607 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
608 }
609 
610 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
611 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
612 {
613 	struct page *node_page;
614 	nid_t nid;
615 	unsigned int ofs_in_node;
616 	block_t source_blkaddr;
617 
618 	nid = le32_to_cpu(sum->nid);
619 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
620 
621 	node_page = f2fs_get_node_page(sbi, nid);
622 	if (IS_ERR(node_page))
623 		return false;
624 
625 	if (f2fs_get_node_info(sbi, nid, dni)) {
626 		f2fs_put_page(node_page, 1);
627 		return false;
628 	}
629 
630 	if (sum->version != dni->version) {
631 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
632 			  __func__);
633 		set_sbi_flag(sbi, SBI_NEED_FSCK);
634 	}
635 
636 	*nofs = ofs_of_node(node_page);
637 	source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
638 	f2fs_put_page(node_page, 1);
639 
640 	if (source_blkaddr != blkaddr) {
641 #ifdef CONFIG_F2FS_CHECK_FS
642 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
643 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
644 
645 		if (unlikely(check_valid_map(sbi, segno, offset))) {
646 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
647 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u\n",
648 						blkaddr, source_blkaddr, segno);
649 				f2fs_bug_on(sbi, 1);
650 			}
651 		}
652 #endif
653 		return false;
654 	}
655 	return true;
656 }
657 
658 static int ra_data_block(struct inode *inode, pgoff_t index)
659 {
660 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
661 	struct address_space *mapping = inode->i_mapping;
662 	struct dnode_of_data dn;
663 	struct page *page;
664 	struct extent_info ei = {0, 0, 0};
665 	struct f2fs_io_info fio = {
666 		.sbi = sbi,
667 		.ino = inode->i_ino,
668 		.type = DATA,
669 		.temp = COLD,
670 		.op = REQ_OP_READ,
671 		.op_flags = 0,
672 		.encrypted_page = NULL,
673 		.in_list = false,
674 		.retry = false,
675 	};
676 	int err;
677 
678 	page = f2fs_grab_cache_page(mapping, index, true);
679 	if (!page)
680 		return -ENOMEM;
681 
682 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
683 		dn.data_blkaddr = ei.blk + index - ei.fofs;
684 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
685 						DATA_GENERIC_ENHANCE_READ))) {
686 			err = -EFSCORRUPTED;
687 			goto put_page;
688 		}
689 		goto got_it;
690 	}
691 
692 	set_new_dnode(&dn, inode, NULL, NULL, 0);
693 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
694 	if (err)
695 		goto put_page;
696 	f2fs_put_dnode(&dn);
697 
698 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
699 		err = -ENOENT;
700 		goto put_page;
701 	}
702 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
703 						DATA_GENERIC_ENHANCE))) {
704 		err = -EFSCORRUPTED;
705 		goto put_page;
706 	}
707 got_it:
708 	/* read page */
709 	fio.page = page;
710 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
711 
712 	/*
713 	 * don't cache encrypted data into meta inode until previous dirty
714 	 * data were writebacked to avoid racing between GC and flush.
715 	 */
716 	f2fs_wait_on_page_writeback(page, DATA, true, true);
717 
718 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
719 
720 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
721 					dn.data_blkaddr,
722 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
723 	if (!fio.encrypted_page) {
724 		err = -ENOMEM;
725 		goto put_page;
726 	}
727 
728 	err = f2fs_submit_page_bio(&fio);
729 	if (err)
730 		goto put_encrypted_page;
731 	f2fs_put_page(fio.encrypted_page, 0);
732 	f2fs_put_page(page, 1);
733 	return 0;
734 put_encrypted_page:
735 	f2fs_put_page(fio.encrypted_page, 1);
736 put_page:
737 	f2fs_put_page(page, 1);
738 	return err;
739 }
740 
741 /*
742  * Move data block via META_MAPPING while keeping locked data page.
743  * This can be used to move blocks, aka LBAs, directly on disk.
744  */
745 static int move_data_block(struct inode *inode, block_t bidx,
746 				int gc_type, unsigned int segno, int off)
747 {
748 	struct f2fs_io_info fio = {
749 		.sbi = F2FS_I_SB(inode),
750 		.ino = inode->i_ino,
751 		.type = DATA,
752 		.temp = COLD,
753 		.op = REQ_OP_READ,
754 		.op_flags = 0,
755 		.encrypted_page = NULL,
756 		.in_list = false,
757 		.retry = false,
758 	};
759 	struct dnode_of_data dn;
760 	struct f2fs_summary sum;
761 	struct node_info ni;
762 	struct page *page, *mpage;
763 	block_t newaddr;
764 	int err = 0;
765 	bool lfs_mode = test_opt(fio.sbi, LFS);
766 
767 	/* do not read out */
768 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
769 	if (!page)
770 		return -ENOMEM;
771 
772 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
773 		err = -ENOENT;
774 		goto out;
775 	}
776 
777 	if (f2fs_is_atomic_file(inode)) {
778 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
779 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
780 		err = -EAGAIN;
781 		goto out;
782 	}
783 
784 	if (f2fs_is_pinned_file(inode)) {
785 		f2fs_pin_file_control(inode, true);
786 		err = -EAGAIN;
787 		goto out;
788 	}
789 
790 	set_new_dnode(&dn, inode, NULL, NULL, 0);
791 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
792 	if (err)
793 		goto out;
794 
795 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
796 		ClearPageUptodate(page);
797 		err = -ENOENT;
798 		goto put_out;
799 	}
800 
801 	/*
802 	 * don't cache encrypted data into meta inode until previous dirty
803 	 * data were writebacked to avoid racing between GC and flush.
804 	 */
805 	f2fs_wait_on_page_writeback(page, DATA, true, true);
806 
807 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
808 
809 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
810 	if (err)
811 		goto put_out;
812 
813 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
814 
815 	/* read page */
816 	fio.page = page;
817 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
818 
819 	if (lfs_mode)
820 		down_write(&fio.sbi->io_order_lock);
821 
822 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
823 					fio.old_blkaddr, false);
824 	if (!mpage)
825 		goto up_out;
826 
827 	fio.encrypted_page = mpage;
828 
829 	/* read source block in mpage */
830 	if (!PageUptodate(mpage)) {
831 		err = f2fs_submit_page_bio(&fio);
832 		if (err) {
833 			f2fs_put_page(mpage, 1);
834 			goto up_out;
835 		}
836 		lock_page(mpage);
837 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
838 						!PageUptodate(mpage))) {
839 			err = -EIO;
840 			f2fs_put_page(mpage, 1);
841 			goto up_out;
842 		}
843 	}
844 
845 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
846 					&sum, CURSEG_COLD_DATA, NULL, false);
847 
848 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
849 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
850 	if (!fio.encrypted_page) {
851 		err = -ENOMEM;
852 		f2fs_put_page(mpage, 1);
853 		goto recover_block;
854 	}
855 
856 	/* write target block */
857 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
858 	memcpy(page_address(fio.encrypted_page),
859 				page_address(mpage), PAGE_SIZE);
860 	f2fs_put_page(mpage, 1);
861 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
862 				fio.old_blkaddr, fio.old_blkaddr);
863 
864 	set_page_dirty(fio.encrypted_page);
865 	if (clear_page_dirty_for_io(fio.encrypted_page))
866 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
867 
868 	set_page_writeback(fio.encrypted_page);
869 	ClearPageError(page);
870 
871 	/* allocate block address */
872 	f2fs_wait_on_page_writeback(dn.node_page, NODE, true, true);
873 
874 	fio.op = REQ_OP_WRITE;
875 	fio.op_flags = REQ_SYNC;
876 	fio.new_blkaddr = newaddr;
877 	f2fs_submit_page_write(&fio);
878 	if (fio.retry) {
879 		err = -EAGAIN;
880 		if (PageWriteback(fio.encrypted_page))
881 			end_page_writeback(fio.encrypted_page);
882 		goto put_page_out;
883 	}
884 
885 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
886 
887 	f2fs_update_data_blkaddr(&dn, newaddr);
888 	set_inode_flag(inode, FI_APPEND_WRITE);
889 	if (page->index == 0)
890 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
891 put_page_out:
892 	f2fs_put_page(fio.encrypted_page, 1);
893 recover_block:
894 	if (err)
895 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
896 								true, true);
897 up_out:
898 	if (lfs_mode)
899 		up_write(&fio.sbi->io_order_lock);
900 put_out:
901 	f2fs_put_dnode(&dn);
902 out:
903 	f2fs_put_page(page, 1);
904 	return err;
905 }
906 
907 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
908 							unsigned int segno, int off)
909 {
910 	struct page *page;
911 	int err = 0;
912 
913 	page = f2fs_get_lock_data_page(inode, bidx, true);
914 	if (IS_ERR(page))
915 		return PTR_ERR(page);
916 
917 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
918 		err = -ENOENT;
919 		goto out;
920 	}
921 
922 	if (f2fs_is_atomic_file(inode)) {
923 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
924 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
925 		err = -EAGAIN;
926 		goto out;
927 	}
928 	if (f2fs_is_pinned_file(inode)) {
929 		if (gc_type == FG_GC)
930 			f2fs_pin_file_control(inode, true);
931 		err = -EAGAIN;
932 		goto out;
933 	}
934 
935 	if (gc_type == BG_GC) {
936 		if (PageWriteback(page)) {
937 			err = -EAGAIN;
938 			goto out;
939 		}
940 		set_page_dirty(page);
941 		set_cold_data(page);
942 	} else {
943 		struct f2fs_io_info fio = {
944 			.sbi = F2FS_I_SB(inode),
945 			.ino = inode->i_ino,
946 			.type = DATA,
947 			.temp = COLD,
948 			.op = REQ_OP_WRITE,
949 			.op_flags = REQ_SYNC,
950 			.old_blkaddr = NULL_ADDR,
951 			.page = page,
952 			.encrypted_page = NULL,
953 			.need_lock = LOCK_REQ,
954 			.io_type = FS_GC_DATA_IO,
955 		};
956 		bool is_dirty = PageDirty(page);
957 
958 retry:
959 		f2fs_wait_on_page_writeback(page, DATA, true, true);
960 
961 		set_page_dirty(page);
962 		if (clear_page_dirty_for_io(page)) {
963 			inode_dec_dirty_pages(inode);
964 			f2fs_remove_dirty_inode(inode);
965 		}
966 
967 		set_cold_data(page);
968 
969 		err = f2fs_do_write_data_page(&fio);
970 		if (err) {
971 			clear_cold_data(page);
972 			if (err == -ENOMEM) {
973 				congestion_wait(BLK_RW_ASYNC, HZ/50);
974 				goto retry;
975 			}
976 			if (is_dirty)
977 				set_page_dirty(page);
978 		}
979 	}
980 out:
981 	f2fs_put_page(page, 1);
982 	return err;
983 }
984 
985 /*
986  * This function tries to get parent node of victim data block, and identifies
987  * data block validity. If the block is valid, copy that with cold status and
988  * modify parent node.
989  * If the parent node is not valid or the data block address is different,
990  * the victim data block is ignored.
991  */
992 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
993 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
994 {
995 	struct super_block *sb = sbi->sb;
996 	struct f2fs_summary *entry;
997 	block_t start_addr;
998 	int off;
999 	int phase = 0;
1000 	int submitted = 0;
1001 
1002 	start_addr = START_BLOCK(sbi, segno);
1003 
1004 next_step:
1005 	entry = sum;
1006 
1007 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
1008 		struct page *data_page;
1009 		struct inode *inode;
1010 		struct node_info dni; /* dnode info for the data */
1011 		unsigned int ofs_in_node, nofs;
1012 		block_t start_bidx;
1013 		nid_t nid = le32_to_cpu(entry->nid);
1014 
1015 		/* stop BG_GC if there is not enough free sections. */
1016 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
1017 			return submitted;
1018 
1019 		if (check_valid_map(sbi, segno, off) == 0)
1020 			continue;
1021 
1022 		if (phase == 0) {
1023 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1024 							META_NAT, true);
1025 			continue;
1026 		}
1027 
1028 		if (phase == 1) {
1029 			f2fs_ra_node_page(sbi, nid);
1030 			continue;
1031 		}
1032 
1033 		/* Get an inode by ino with checking validity */
1034 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1035 			continue;
1036 
1037 		if (phase == 2) {
1038 			f2fs_ra_node_page(sbi, dni.ino);
1039 			continue;
1040 		}
1041 
1042 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1043 
1044 		if (phase == 3) {
1045 			inode = f2fs_iget(sb, dni.ino);
1046 			if (IS_ERR(inode) || is_bad_inode(inode))
1047 				continue;
1048 
1049 			if (!down_write_trylock(
1050 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1051 				iput(inode);
1052 				sbi->skipped_gc_rwsem++;
1053 				continue;
1054 			}
1055 
1056 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1057 								ofs_in_node;
1058 
1059 			if (f2fs_post_read_required(inode)) {
1060 				int err = ra_data_block(inode, start_bidx);
1061 
1062 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1063 				if (err) {
1064 					iput(inode);
1065 					continue;
1066 				}
1067 				add_gc_inode(gc_list, inode);
1068 				continue;
1069 			}
1070 
1071 			data_page = f2fs_get_read_data_page(inode,
1072 						start_bidx, REQ_RAHEAD, true);
1073 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1074 			if (IS_ERR(data_page)) {
1075 				iput(inode);
1076 				continue;
1077 			}
1078 
1079 			f2fs_put_page(data_page, 0);
1080 			add_gc_inode(gc_list, inode);
1081 			continue;
1082 		}
1083 
1084 		/* phase 4 */
1085 		inode = find_gc_inode(gc_list, dni.ino);
1086 		if (inode) {
1087 			struct f2fs_inode_info *fi = F2FS_I(inode);
1088 			bool locked = false;
1089 			int err;
1090 
1091 			if (S_ISREG(inode->i_mode)) {
1092 				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1093 					continue;
1094 				if (!down_write_trylock(
1095 						&fi->i_gc_rwsem[WRITE])) {
1096 					sbi->skipped_gc_rwsem++;
1097 					up_write(&fi->i_gc_rwsem[READ]);
1098 					continue;
1099 				}
1100 				locked = true;
1101 
1102 				/* wait for all inflight aio data */
1103 				inode_dio_wait(inode);
1104 			}
1105 
1106 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1107 								+ ofs_in_node;
1108 			if (f2fs_post_read_required(inode))
1109 				err = move_data_block(inode, start_bidx,
1110 							gc_type, segno, off);
1111 			else
1112 				err = move_data_page(inode, start_bidx, gc_type,
1113 								segno, off);
1114 
1115 			if (!err && (gc_type == FG_GC ||
1116 					f2fs_post_read_required(inode)))
1117 				submitted++;
1118 
1119 			if (locked) {
1120 				up_write(&fi->i_gc_rwsem[WRITE]);
1121 				up_write(&fi->i_gc_rwsem[READ]);
1122 			}
1123 
1124 			stat_inc_data_blk_count(sbi, 1, gc_type);
1125 		}
1126 	}
1127 
1128 	if (++phase < 5)
1129 		goto next_step;
1130 
1131 	return submitted;
1132 }
1133 
1134 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1135 			int gc_type)
1136 {
1137 	struct sit_info *sit_i = SIT_I(sbi);
1138 	int ret;
1139 
1140 	down_write(&sit_i->sentry_lock);
1141 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1142 					      NO_CHECK_TYPE, LFS);
1143 	up_write(&sit_i->sentry_lock);
1144 	return ret;
1145 }
1146 
1147 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1148 				unsigned int start_segno,
1149 				struct gc_inode_list *gc_list, int gc_type)
1150 {
1151 	struct page *sum_page;
1152 	struct f2fs_summary_block *sum;
1153 	struct blk_plug plug;
1154 	unsigned int segno = start_segno;
1155 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1156 	int seg_freed = 0, migrated = 0;
1157 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1158 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1159 	int submitted = 0;
1160 
1161 	if (__is_large_section(sbi))
1162 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1163 
1164 	/* readahead multi ssa blocks those have contiguous address */
1165 	if (__is_large_section(sbi))
1166 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1167 					end_segno - segno, META_SSA, true);
1168 
1169 	/* reference all summary page */
1170 	while (segno < end_segno) {
1171 		sum_page = f2fs_get_sum_page(sbi, segno++);
1172 		if (IS_ERR(sum_page)) {
1173 			int err = PTR_ERR(sum_page);
1174 
1175 			end_segno = segno - 1;
1176 			for (segno = start_segno; segno < end_segno; segno++) {
1177 				sum_page = find_get_page(META_MAPPING(sbi),
1178 						GET_SUM_BLOCK(sbi, segno));
1179 				f2fs_put_page(sum_page, 0);
1180 				f2fs_put_page(sum_page, 0);
1181 			}
1182 			return err;
1183 		}
1184 		unlock_page(sum_page);
1185 	}
1186 
1187 	blk_start_plug(&plug);
1188 
1189 	for (segno = start_segno; segno < end_segno; segno++) {
1190 
1191 		/* find segment summary of victim */
1192 		sum_page = find_get_page(META_MAPPING(sbi),
1193 					GET_SUM_BLOCK(sbi, segno));
1194 		f2fs_put_page(sum_page, 0);
1195 
1196 		if (get_valid_blocks(sbi, segno, false) == 0)
1197 			goto freed;
1198 		if (__is_large_section(sbi) &&
1199 				migrated >= sbi->migration_granularity)
1200 			goto skip;
1201 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1202 			goto skip;
1203 
1204 		sum = page_address(sum_page);
1205 		if (type != GET_SUM_TYPE((&sum->footer))) {
1206 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1207 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1208 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1209 			f2fs_stop_checkpoint(sbi, false);
1210 			goto skip;
1211 		}
1212 
1213 		/*
1214 		 * this is to avoid deadlock:
1215 		 * - lock_page(sum_page)         - f2fs_replace_block
1216 		 *  - check_valid_map()            - down_write(sentry_lock)
1217 		 *   - down_read(sentry_lock)     - change_curseg()
1218 		 *                                  - lock_page(sum_page)
1219 		 */
1220 		if (type == SUM_TYPE_NODE)
1221 			submitted += gc_node_segment(sbi, sum->entries, segno,
1222 								gc_type);
1223 		else
1224 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1225 							segno, gc_type);
1226 
1227 		stat_inc_seg_count(sbi, type, gc_type);
1228 
1229 freed:
1230 		if (gc_type == FG_GC &&
1231 				get_valid_blocks(sbi, segno, false) == 0)
1232 			seg_freed++;
1233 		migrated++;
1234 
1235 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1236 			sbi->next_victim_seg[gc_type] = segno + 1;
1237 skip:
1238 		f2fs_put_page(sum_page, 0);
1239 	}
1240 
1241 	if (submitted)
1242 		f2fs_submit_merged_write(sbi,
1243 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1244 
1245 	blk_finish_plug(&plug);
1246 
1247 	stat_inc_call_count(sbi->stat_info);
1248 
1249 	return seg_freed;
1250 }
1251 
1252 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1253 			bool background, unsigned int segno)
1254 {
1255 	int gc_type = sync ? FG_GC : BG_GC;
1256 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1257 	int ret = 0;
1258 	struct cp_control cpc;
1259 	unsigned int init_segno = segno;
1260 	struct gc_inode_list gc_list = {
1261 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1262 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1263 	};
1264 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1265 	unsigned long long first_skipped;
1266 	unsigned int skipped_round = 0, round = 0;
1267 
1268 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1269 				get_pages(sbi, F2FS_DIRTY_NODES),
1270 				get_pages(sbi, F2FS_DIRTY_DENTS),
1271 				get_pages(sbi, F2FS_DIRTY_IMETA),
1272 				free_sections(sbi),
1273 				free_segments(sbi),
1274 				reserved_segments(sbi),
1275 				prefree_segments(sbi));
1276 
1277 	cpc.reason = __get_cp_reason(sbi);
1278 	sbi->skipped_gc_rwsem = 0;
1279 	first_skipped = last_skipped;
1280 gc_more:
1281 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1282 		ret = -EINVAL;
1283 		goto stop;
1284 	}
1285 	if (unlikely(f2fs_cp_error(sbi))) {
1286 		ret = -EIO;
1287 		goto stop;
1288 	}
1289 
1290 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1291 		/*
1292 		 * For example, if there are many prefree_segments below given
1293 		 * threshold, we can make them free by checkpoint. Then, we
1294 		 * secure free segments which doesn't need fggc any more.
1295 		 */
1296 		if (prefree_segments(sbi) &&
1297 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1298 			ret = f2fs_write_checkpoint(sbi, &cpc);
1299 			if (ret)
1300 				goto stop;
1301 		}
1302 		if (has_not_enough_free_secs(sbi, 0, 0))
1303 			gc_type = FG_GC;
1304 	}
1305 
1306 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1307 	if (gc_type == BG_GC && !background) {
1308 		ret = -EINVAL;
1309 		goto stop;
1310 	}
1311 	if (!__get_victim(sbi, &segno, gc_type)) {
1312 		ret = -ENODATA;
1313 		goto stop;
1314 	}
1315 
1316 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1317 	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1318 		sec_freed++;
1319 	total_freed += seg_freed;
1320 
1321 	if (gc_type == FG_GC) {
1322 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1323 						sbi->skipped_gc_rwsem)
1324 			skipped_round++;
1325 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1326 		round++;
1327 	}
1328 
1329 	if (gc_type == FG_GC && seg_freed)
1330 		sbi->cur_victim_sec = NULL_SEGNO;
1331 
1332 	if (sync)
1333 		goto stop;
1334 
1335 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1336 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1337 					skipped_round * 2 < round) {
1338 			segno = NULL_SEGNO;
1339 			goto gc_more;
1340 		}
1341 
1342 		if (first_skipped < last_skipped &&
1343 				(last_skipped - first_skipped) >
1344 						sbi->skipped_gc_rwsem) {
1345 			f2fs_drop_inmem_pages_all(sbi, true);
1346 			segno = NULL_SEGNO;
1347 			goto gc_more;
1348 		}
1349 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1350 			ret = f2fs_write_checkpoint(sbi, &cpc);
1351 	}
1352 stop:
1353 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1354 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1355 
1356 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1357 				get_pages(sbi, F2FS_DIRTY_NODES),
1358 				get_pages(sbi, F2FS_DIRTY_DENTS),
1359 				get_pages(sbi, F2FS_DIRTY_IMETA),
1360 				free_sections(sbi),
1361 				free_segments(sbi),
1362 				reserved_segments(sbi),
1363 				prefree_segments(sbi));
1364 
1365 	mutex_unlock(&sbi->gc_mutex);
1366 
1367 	put_gc_inode(&gc_list);
1368 
1369 	if (sync && !ret)
1370 		ret = sec_freed ? 0 : -EAGAIN;
1371 	return ret;
1372 }
1373 
1374 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1375 {
1376 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1377 
1378 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1379 
1380 	/* give warm/cold data area from slower device */
1381 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1382 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1383 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1384 }
1385 
1386 static int free_segment_range(struct f2fs_sb_info *sbi, unsigned int start,
1387 							unsigned int end)
1388 {
1389 	int type;
1390 	unsigned int segno, next_inuse;
1391 	int err = 0;
1392 
1393 	/* Move out cursegs from the target range */
1394 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
1395 		allocate_segment_for_resize(sbi, type, start, end);
1396 
1397 	/* do GC to move out valid blocks in the range */
1398 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1399 		struct gc_inode_list gc_list = {
1400 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1401 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1402 		};
1403 
1404 		mutex_lock(&sbi->gc_mutex);
1405 		do_garbage_collect(sbi, segno, &gc_list, FG_GC);
1406 		mutex_unlock(&sbi->gc_mutex);
1407 		put_gc_inode(&gc_list);
1408 
1409 		if (get_valid_blocks(sbi, segno, true))
1410 			return -EAGAIN;
1411 	}
1412 
1413 	err = f2fs_sync_fs(sbi->sb, 1);
1414 	if (err)
1415 		return err;
1416 
1417 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1418 	if (next_inuse <= end) {
1419 		f2fs_err(sbi, "segno %u should be free but still inuse!",
1420 			 next_inuse);
1421 		f2fs_bug_on(sbi, 1);
1422 	}
1423 	return err;
1424 }
1425 
1426 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1427 {
1428 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1429 	int section_count = le32_to_cpu(raw_sb->section_count);
1430 	int segment_count = le32_to_cpu(raw_sb->segment_count);
1431 	int segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1432 	long long block_count = le64_to_cpu(raw_sb->block_count);
1433 	int segs = secs * sbi->segs_per_sec;
1434 
1435 	raw_sb->section_count = cpu_to_le32(section_count + secs);
1436 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1437 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1438 	raw_sb->block_count = cpu_to_le64(block_count +
1439 					(long long)segs * sbi->blocks_per_seg);
1440 }
1441 
1442 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1443 {
1444 	int segs = secs * sbi->segs_per_sec;
1445 	long long user_block_count =
1446 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1447 
1448 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1449 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1450 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1451 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1452 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count +
1453 					(long long)segs * sbi->blocks_per_seg);
1454 }
1455 
1456 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1457 {
1458 	__u64 old_block_count, shrunk_blocks;
1459 	unsigned int secs;
1460 	int gc_mode, gc_type;
1461 	int err = 0;
1462 	__u32 rem;
1463 
1464 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1465 	if (block_count > old_block_count)
1466 		return -EINVAL;
1467 
1468 	/* new fs size should align to section size */
1469 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1470 	if (rem)
1471 		return -EINVAL;
1472 
1473 	if (block_count == old_block_count)
1474 		return 0;
1475 
1476 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
1477 		f2fs_err(sbi, "Should run fsck to repair first.");
1478 		return -EFSCORRUPTED;
1479 	}
1480 
1481 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
1482 		f2fs_err(sbi, "Checkpoint should be enabled.");
1483 		return -EINVAL;
1484 	}
1485 
1486 	freeze_bdev(sbi->sb->s_bdev);
1487 
1488 	shrunk_blocks = old_block_count - block_count;
1489 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
1490 	spin_lock(&sbi->stat_lock);
1491 	if (shrunk_blocks + valid_user_blocks(sbi) +
1492 		sbi->current_reserved_blocks + sbi->unusable_block_count +
1493 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
1494 		err = -ENOSPC;
1495 	else
1496 		sbi->user_block_count -= shrunk_blocks;
1497 	spin_unlock(&sbi->stat_lock);
1498 	if (err) {
1499 		thaw_bdev(sbi->sb->s_bdev, sbi->sb);
1500 		return err;
1501 	}
1502 
1503 	mutex_lock(&sbi->resize_mutex);
1504 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
1505 
1506 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1507 
1508 	MAIN_SECS(sbi) -= secs;
1509 
1510 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1511 		if (SIT_I(sbi)->last_victim[gc_mode] >=
1512 					MAIN_SECS(sbi) * sbi->segs_per_sec)
1513 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1514 
1515 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1516 		if (sbi->next_victim_seg[gc_type] >=
1517 					MAIN_SECS(sbi) * sbi->segs_per_sec)
1518 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1519 
1520 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1521 
1522 	err = free_segment_range(sbi, MAIN_SECS(sbi) * sbi->segs_per_sec,
1523 			MAIN_SEGS(sbi) - 1);
1524 	if (err)
1525 		goto out;
1526 
1527 	update_sb_metadata(sbi, -secs);
1528 
1529 	err = f2fs_commit_super(sbi, false);
1530 	if (err) {
1531 		update_sb_metadata(sbi, secs);
1532 		goto out;
1533 	}
1534 
1535 	update_fs_metadata(sbi, -secs);
1536 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1537 	err = f2fs_sync_fs(sbi->sb, 1);
1538 	if (err) {
1539 		update_fs_metadata(sbi, secs);
1540 		update_sb_metadata(sbi, secs);
1541 		f2fs_commit_super(sbi, false);
1542 	}
1543 out:
1544 	if (err) {
1545 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1546 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
1547 
1548 		MAIN_SECS(sbi) += secs;
1549 		spin_lock(&sbi->stat_lock);
1550 		sbi->user_block_count += shrunk_blocks;
1551 		spin_unlock(&sbi->stat_lock);
1552 	}
1553 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1554 	mutex_unlock(&sbi->resize_mutex);
1555 	thaw_bdev(sbi->sb->s_bdev, sbi->sb);
1556 	return err;
1557 }
1558