xref: /openbmc/linux/fs/f2fs/gc.c (revision 455f9726)
1 /*
2  * fs/f2fs/gc.c
3  *
4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5  *             http://www.samsung.com/
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #include <linux/fs.h>
12 #include <linux/module.h>
13 #include <linux/backing-dev.h>
14 #include <linux/init.h>
15 #include <linux/f2fs_fs.h>
16 #include <linux/kthread.h>
17 #include <linux/delay.h>
18 #include <linux/freezer.h>
19 #include <linux/blkdev.h>
20 
21 #include "f2fs.h"
22 #include "node.h"
23 #include "segment.h"
24 #include "gc.h"
25 #include <trace/events/f2fs.h>
26 
27 static struct kmem_cache *winode_slab;
28 
29 static int gc_thread_func(void *data)
30 {
31 	struct f2fs_sb_info *sbi = data;
32 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
33 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
34 	long wait_ms;
35 
36 	wait_ms = gc_th->min_sleep_time;
37 
38 	do {
39 		if (try_to_freeze())
40 			continue;
41 		else
42 			wait_event_interruptible_timeout(*wq,
43 						kthread_should_stop(),
44 						msecs_to_jiffies(wait_ms));
45 		if (kthread_should_stop())
46 			break;
47 
48 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
49 			wait_ms = increase_sleep_time(gc_th, wait_ms);
50 			continue;
51 		}
52 
53 		/*
54 		 * [GC triggering condition]
55 		 * 0. GC is not conducted currently.
56 		 * 1. There are enough dirty segments.
57 		 * 2. IO subsystem is idle by checking the # of writeback pages.
58 		 * 3. IO subsystem is idle by checking the # of requests in
59 		 *    bdev's request list.
60 		 *
61 		 * Note) We have to avoid triggering GCs too much frequently.
62 		 * Because it is possible that some segments can be
63 		 * invalidated soon after by user update or deletion.
64 		 * So, I'd like to wait some time to collect dirty segments.
65 		 */
66 		if (!mutex_trylock(&sbi->gc_mutex))
67 			continue;
68 
69 		if (!is_idle(sbi)) {
70 			wait_ms = increase_sleep_time(gc_th, wait_ms);
71 			mutex_unlock(&sbi->gc_mutex);
72 			continue;
73 		}
74 
75 		if (has_enough_invalid_blocks(sbi))
76 			wait_ms = decrease_sleep_time(gc_th, wait_ms);
77 		else
78 			wait_ms = increase_sleep_time(gc_th, wait_ms);
79 
80 		stat_inc_bggc_count(sbi);
81 
82 		/* if return value is not zero, no victim was selected */
83 		if (f2fs_gc(sbi))
84 			wait_ms = gc_th->no_gc_sleep_time;
85 
86 		/* balancing f2fs's metadata periodically */
87 		f2fs_balance_fs_bg(sbi);
88 
89 	} while (!kthread_should_stop());
90 	return 0;
91 }
92 
93 int start_gc_thread(struct f2fs_sb_info *sbi)
94 {
95 	struct f2fs_gc_kthread *gc_th;
96 	dev_t dev = sbi->sb->s_bdev->bd_dev;
97 	int err = 0;
98 
99 	if (!test_opt(sbi, BG_GC))
100 		goto out;
101 	gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
102 	if (!gc_th) {
103 		err = -ENOMEM;
104 		goto out;
105 	}
106 
107 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
108 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
109 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
110 
111 	gc_th->gc_idle = 0;
112 
113 	sbi->gc_thread = gc_th;
114 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
115 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
116 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
117 	if (IS_ERR(gc_th->f2fs_gc_task)) {
118 		err = PTR_ERR(gc_th->f2fs_gc_task);
119 		kfree(gc_th);
120 		sbi->gc_thread = NULL;
121 	}
122 out:
123 	return err;
124 }
125 
126 void stop_gc_thread(struct f2fs_sb_info *sbi)
127 {
128 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
129 	if (!gc_th)
130 		return;
131 	kthread_stop(gc_th->f2fs_gc_task);
132 	kfree(gc_th);
133 	sbi->gc_thread = NULL;
134 }
135 
136 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
137 {
138 	int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
139 
140 	if (gc_th && gc_th->gc_idle) {
141 		if (gc_th->gc_idle == 1)
142 			gc_mode = GC_CB;
143 		else if (gc_th->gc_idle == 2)
144 			gc_mode = GC_GREEDY;
145 	}
146 	return gc_mode;
147 }
148 
149 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
150 			int type, struct victim_sel_policy *p)
151 {
152 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
153 
154 	if (p->alloc_mode == SSR) {
155 		p->gc_mode = GC_GREEDY;
156 		p->dirty_segmap = dirty_i->dirty_segmap[type];
157 		p->max_search = dirty_i->nr_dirty[type];
158 		p->ofs_unit = 1;
159 	} else {
160 		p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
161 		p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
162 		p->max_search = dirty_i->nr_dirty[DIRTY];
163 		p->ofs_unit = sbi->segs_per_sec;
164 	}
165 
166 	if (p->max_search > sbi->max_victim_search)
167 		p->max_search = sbi->max_victim_search;
168 
169 	p->offset = sbi->last_victim[p->gc_mode];
170 }
171 
172 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
173 				struct victim_sel_policy *p)
174 {
175 	/* SSR allocates in a segment unit */
176 	if (p->alloc_mode == SSR)
177 		return 1 << sbi->log_blocks_per_seg;
178 	if (p->gc_mode == GC_GREEDY)
179 		return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
180 	else if (p->gc_mode == GC_CB)
181 		return UINT_MAX;
182 	else /* No other gc_mode */
183 		return 0;
184 }
185 
186 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
187 {
188 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
189 	unsigned int secno;
190 
191 	/*
192 	 * If the gc_type is FG_GC, we can select victim segments
193 	 * selected by background GC before.
194 	 * Those segments guarantee they have small valid blocks.
195 	 */
196 	for_each_set_bit(secno, dirty_i->victim_secmap, TOTAL_SECS(sbi)) {
197 		if (sec_usage_check(sbi, secno))
198 			continue;
199 		clear_bit(secno, dirty_i->victim_secmap);
200 		return secno * sbi->segs_per_sec;
201 	}
202 	return NULL_SEGNO;
203 }
204 
205 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
206 {
207 	struct sit_info *sit_i = SIT_I(sbi);
208 	unsigned int secno = GET_SECNO(sbi, segno);
209 	unsigned int start = secno * sbi->segs_per_sec;
210 	unsigned long long mtime = 0;
211 	unsigned int vblocks;
212 	unsigned char age = 0;
213 	unsigned char u;
214 	unsigned int i;
215 
216 	for (i = 0; i < sbi->segs_per_sec; i++)
217 		mtime += get_seg_entry(sbi, start + i)->mtime;
218 	vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
219 
220 	mtime = div_u64(mtime, sbi->segs_per_sec);
221 	vblocks = div_u64(vblocks, sbi->segs_per_sec);
222 
223 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
224 
225 	/* Handle if the system time is changed by user */
226 	if (mtime < sit_i->min_mtime)
227 		sit_i->min_mtime = mtime;
228 	if (mtime > sit_i->max_mtime)
229 		sit_i->max_mtime = mtime;
230 	if (sit_i->max_mtime != sit_i->min_mtime)
231 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
232 				sit_i->max_mtime - sit_i->min_mtime);
233 
234 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
235 }
236 
237 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
238 			unsigned int segno, struct victim_sel_policy *p)
239 {
240 	if (p->alloc_mode == SSR)
241 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
242 
243 	/* alloc_mode == LFS */
244 	if (p->gc_mode == GC_GREEDY)
245 		return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
246 	else
247 		return get_cb_cost(sbi, segno);
248 }
249 
250 /*
251  * This function is called from two paths.
252  * One is garbage collection and the other is SSR segment selection.
253  * When it is called during GC, it just gets a victim segment
254  * and it does not remove it from dirty seglist.
255  * When it is called from SSR segment selection, it finds a segment
256  * which has minimum valid blocks and removes it from dirty seglist.
257  */
258 static int get_victim_by_default(struct f2fs_sb_info *sbi,
259 		unsigned int *result, int gc_type, int type, char alloc_mode)
260 {
261 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
262 	struct victim_sel_policy p;
263 	unsigned int secno, max_cost;
264 	int nsearched = 0;
265 
266 	p.alloc_mode = alloc_mode;
267 	select_policy(sbi, gc_type, type, &p);
268 
269 	p.min_segno = NULL_SEGNO;
270 	p.min_cost = max_cost = get_max_cost(sbi, &p);
271 
272 	mutex_lock(&dirty_i->seglist_lock);
273 
274 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
275 		p.min_segno = check_bg_victims(sbi);
276 		if (p.min_segno != NULL_SEGNO)
277 			goto got_it;
278 	}
279 
280 	while (1) {
281 		unsigned long cost;
282 		unsigned int segno;
283 
284 		segno = find_next_bit(p.dirty_segmap,
285 						TOTAL_SEGS(sbi), p.offset);
286 		if (segno >= TOTAL_SEGS(sbi)) {
287 			if (sbi->last_victim[p.gc_mode]) {
288 				sbi->last_victim[p.gc_mode] = 0;
289 				p.offset = 0;
290 				continue;
291 			}
292 			break;
293 		}
294 
295 		p.offset = segno + p.ofs_unit;
296 		if (p.ofs_unit > 1)
297 			p.offset -= segno % p.ofs_unit;
298 
299 		secno = GET_SECNO(sbi, segno);
300 
301 		if (sec_usage_check(sbi, secno))
302 			continue;
303 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
304 			continue;
305 
306 		cost = get_gc_cost(sbi, segno, &p);
307 
308 		if (p.min_cost > cost) {
309 			p.min_segno = segno;
310 			p.min_cost = cost;
311 		} else if (unlikely(cost == max_cost)) {
312 			continue;
313 		}
314 
315 		if (nsearched++ >= p.max_search) {
316 			sbi->last_victim[p.gc_mode] = segno;
317 			break;
318 		}
319 	}
320 	if (p.min_segno != NULL_SEGNO) {
321 got_it:
322 		if (p.alloc_mode == LFS) {
323 			secno = GET_SECNO(sbi, p.min_segno);
324 			if (gc_type == FG_GC)
325 				sbi->cur_victim_sec = secno;
326 			else
327 				set_bit(secno, dirty_i->victim_secmap);
328 		}
329 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
330 
331 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
332 				sbi->cur_victim_sec,
333 				prefree_segments(sbi), free_segments(sbi));
334 	}
335 	mutex_unlock(&dirty_i->seglist_lock);
336 
337 	return (p.min_segno == NULL_SEGNO) ? 0 : 1;
338 }
339 
340 static const struct victim_selection default_v_ops = {
341 	.get_victim = get_victim_by_default,
342 };
343 
344 static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
345 {
346 	struct inode_entry *ie;
347 
348 	list_for_each_entry(ie, ilist, list)
349 		if (ie->inode->i_ino == ino)
350 			return ie->inode;
351 	return NULL;
352 }
353 
354 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
355 {
356 	struct inode_entry *new_ie;
357 
358 	if (inode == find_gc_inode(inode->i_ino, ilist)) {
359 		iput(inode);
360 		return;
361 	}
362 
363 	new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
364 	new_ie->inode = inode;
365 	list_add_tail(&new_ie->list, ilist);
366 }
367 
368 static void put_gc_inode(struct list_head *ilist)
369 {
370 	struct inode_entry *ie, *next_ie;
371 	list_for_each_entry_safe(ie, next_ie, ilist, list) {
372 		iput(ie->inode);
373 		list_del(&ie->list);
374 		kmem_cache_free(winode_slab, ie);
375 	}
376 }
377 
378 static int check_valid_map(struct f2fs_sb_info *sbi,
379 				unsigned int segno, int offset)
380 {
381 	struct sit_info *sit_i = SIT_I(sbi);
382 	struct seg_entry *sentry;
383 	int ret;
384 
385 	mutex_lock(&sit_i->sentry_lock);
386 	sentry = get_seg_entry(sbi, segno);
387 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
388 	mutex_unlock(&sit_i->sentry_lock);
389 	return ret;
390 }
391 
392 /*
393  * This function compares node address got in summary with that in NAT.
394  * On validity, copy that node with cold status, otherwise (invalid node)
395  * ignore that.
396  */
397 static void gc_node_segment(struct f2fs_sb_info *sbi,
398 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
399 {
400 	bool initial = true;
401 	struct f2fs_summary *entry;
402 	int off;
403 
404 next_step:
405 	entry = sum;
406 
407 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
408 		nid_t nid = le32_to_cpu(entry->nid);
409 		struct page *node_page;
410 
411 		/* stop BG_GC if there is not enough free sections. */
412 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
413 			return;
414 
415 		if (check_valid_map(sbi, segno, off) == 0)
416 			continue;
417 
418 		if (initial) {
419 			ra_node_page(sbi, nid);
420 			continue;
421 		}
422 		node_page = get_node_page(sbi, nid);
423 		if (IS_ERR(node_page))
424 			continue;
425 
426 		/* set page dirty and write it */
427 		if (gc_type == FG_GC) {
428 			f2fs_wait_on_page_writeback(node_page, NODE);
429 			set_page_dirty(node_page);
430 		} else {
431 			if (!PageWriteback(node_page))
432 				set_page_dirty(node_page);
433 		}
434 		f2fs_put_page(node_page, 1);
435 		stat_inc_node_blk_count(sbi, 1);
436 	}
437 
438 	if (initial) {
439 		initial = false;
440 		goto next_step;
441 	}
442 
443 	if (gc_type == FG_GC) {
444 		struct writeback_control wbc = {
445 			.sync_mode = WB_SYNC_ALL,
446 			.nr_to_write = LONG_MAX,
447 			.for_reclaim = 0,
448 		};
449 		sync_node_pages(sbi, 0, &wbc);
450 
451 		/*
452 		 * In the case of FG_GC, it'd be better to reclaim this victim
453 		 * completely.
454 		 */
455 		if (get_valid_blocks(sbi, segno, 1) != 0)
456 			goto next_step;
457 	}
458 }
459 
460 /*
461  * Calculate start block index indicating the given node offset.
462  * Be careful, caller should give this node offset only indicating direct node
463  * blocks. If any node offsets, which point the other types of node blocks such
464  * as indirect or double indirect node blocks, are given, it must be a caller's
465  * bug.
466  */
467 block_t start_bidx_of_node(unsigned int node_ofs, struct f2fs_inode_info *fi)
468 {
469 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
470 	unsigned int bidx;
471 
472 	if (node_ofs == 0)
473 		return 0;
474 
475 	if (node_ofs <= 2) {
476 		bidx = node_ofs - 1;
477 	} else if (node_ofs <= indirect_blks) {
478 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
479 		bidx = node_ofs - 2 - dec;
480 	} else {
481 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
482 		bidx = node_ofs - 5 - dec;
483 	}
484 	return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi);
485 }
486 
487 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
488 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
489 {
490 	struct page *node_page;
491 	nid_t nid;
492 	unsigned int ofs_in_node;
493 	block_t source_blkaddr;
494 
495 	nid = le32_to_cpu(sum->nid);
496 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
497 
498 	node_page = get_node_page(sbi, nid);
499 	if (IS_ERR(node_page))
500 		return 0;
501 
502 	get_node_info(sbi, nid, dni);
503 
504 	if (sum->version != dni->version) {
505 		f2fs_put_page(node_page, 1);
506 		return 0;
507 	}
508 
509 	*nofs = ofs_of_node(node_page);
510 	source_blkaddr = datablock_addr(node_page, ofs_in_node);
511 	f2fs_put_page(node_page, 1);
512 
513 	if (source_blkaddr != blkaddr)
514 		return 0;
515 	return 1;
516 }
517 
518 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
519 {
520 	struct f2fs_io_info fio = {
521 		.type = DATA,
522 		.rw = WRITE_SYNC,
523 	};
524 
525 	if (gc_type == BG_GC) {
526 		if (PageWriteback(page))
527 			goto out;
528 		set_page_dirty(page);
529 		set_cold_data(page);
530 	} else {
531 		f2fs_wait_on_page_writeback(page, DATA);
532 
533 		if (clear_page_dirty_for_io(page))
534 			inode_dec_dirty_dents(inode);
535 		set_cold_data(page);
536 		do_write_data_page(page, &fio);
537 		clear_cold_data(page);
538 	}
539 out:
540 	f2fs_put_page(page, 1);
541 }
542 
543 /*
544  * This function tries to get parent node of victim data block, and identifies
545  * data block validity. If the block is valid, copy that with cold status and
546  * modify parent node.
547  * If the parent node is not valid or the data block address is different,
548  * the victim data block is ignored.
549  */
550 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
551 		struct list_head *ilist, unsigned int segno, int gc_type)
552 {
553 	struct super_block *sb = sbi->sb;
554 	struct f2fs_summary *entry;
555 	block_t start_addr;
556 	int off;
557 	int phase = 0;
558 
559 	start_addr = START_BLOCK(sbi, segno);
560 
561 next_step:
562 	entry = sum;
563 
564 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
565 		struct page *data_page;
566 		struct inode *inode;
567 		struct node_info dni; /* dnode info for the data */
568 		unsigned int ofs_in_node, nofs;
569 		block_t start_bidx;
570 
571 		/* stop BG_GC if there is not enough free sections. */
572 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
573 			return;
574 
575 		if (check_valid_map(sbi, segno, off) == 0)
576 			continue;
577 
578 		if (phase == 0) {
579 			ra_node_page(sbi, le32_to_cpu(entry->nid));
580 			continue;
581 		}
582 
583 		/* Get an inode by ino with checking validity */
584 		if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
585 			continue;
586 
587 		if (phase == 1) {
588 			ra_node_page(sbi, dni.ino);
589 			continue;
590 		}
591 
592 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
593 
594 		if (phase == 2) {
595 			inode = f2fs_iget(sb, dni.ino);
596 			if (IS_ERR(inode))
597 				continue;
598 
599 			start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
600 
601 			data_page = find_data_page(inode,
602 					start_bidx + ofs_in_node, false);
603 			if (IS_ERR(data_page))
604 				goto next_iput;
605 
606 			f2fs_put_page(data_page, 0);
607 			add_gc_inode(inode, ilist);
608 		} else {
609 			inode = find_gc_inode(dni.ino, ilist);
610 			if (inode) {
611 				start_bidx = start_bidx_of_node(nofs,
612 								F2FS_I(inode));
613 				data_page = get_lock_data_page(inode,
614 						start_bidx + ofs_in_node);
615 				if (IS_ERR(data_page))
616 					continue;
617 				move_data_page(inode, data_page, gc_type);
618 				stat_inc_data_blk_count(sbi, 1);
619 			}
620 		}
621 		continue;
622 next_iput:
623 		iput(inode);
624 	}
625 
626 	if (++phase < 4)
627 		goto next_step;
628 
629 	if (gc_type == FG_GC) {
630 		f2fs_submit_merged_bio(sbi, DATA, WRITE);
631 
632 		/*
633 		 * In the case of FG_GC, it'd be better to reclaim this victim
634 		 * completely.
635 		 */
636 		if (get_valid_blocks(sbi, segno, 1) != 0) {
637 			phase = 2;
638 			goto next_step;
639 		}
640 	}
641 }
642 
643 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
644 						int gc_type, int type)
645 {
646 	struct sit_info *sit_i = SIT_I(sbi);
647 	int ret;
648 	mutex_lock(&sit_i->sentry_lock);
649 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
650 	mutex_unlock(&sit_i->sentry_lock);
651 	return ret;
652 }
653 
654 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
655 				struct list_head *ilist, int gc_type)
656 {
657 	struct page *sum_page;
658 	struct f2fs_summary_block *sum;
659 	struct blk_plug plug;
660 
661 	/* read segment summary of victim */
662 	sum_page = get_sum_page(sbi, segno);
663 
664 	blk_start_plug(&plug);
665 
666 	sum = page_address(sum_page);
667 
668 	switch (GET_SUM_TYPE((&sum->footer))) {
669 	case SUM_TYPE_NODE:
670 		gc_node_segment(sbi, sum->entries, segno, gc_type);
671 		break;
672 	case SUM_TYPE_DATA:
673 		gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
674 		break;
675 	}
676 	blk_finish_plug(&plug);
677 
678 	stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
679 	stat_inc_call_count(sbi->stat_info);
680 
681 	f2fs_put_page(sum_page, 1);
682 }
683 
684 int f2fs_gc(struct f2fs_sb_info *sbi)
685 {
686 	struct list_head ilist;
687 	unsigned int segno, i;
688 	int gc_type = BG_GC;
689 	int nfree = 0;
690 	int ret = -1;
691 
692 	INIT_LIST_HEAD(&ilist);
693 gc_more:
694 	if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
695 		goto stop;
696 	if (unlikely(is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)))
697 		goto stop;
698 
699 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
700 		gc_type = FG_GC;
701 		write_checkpoint(sbi, false);
702 	}
703 
704 	if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
705 		goto stop;
706 	ret = 0;
707 
708 	/* readahead multi ssa blocks those have contiguous address */
709 	if (sbi->segs_per_sec > 1)
710 		ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
711 								META_SSA);
712 
713 	for (i = 0; i < sbi->segs_per_sec; i++)
714 		do_garbage_collect(sbi, segno + i, &ilist, gc_type);
715 
716 	if (gc_type == FG_GC) {
717 		sbi->cur_victim_sec = NULL_SEGNO;
718 		nfree++;
719 		WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
720 	}
721 
722 	if (has_not_enough_free_secs(sbi, nfree))
723 		goto gc_more;
724 
725 	if (gc_type == FG_GC)
726 		write_checkpoint(sbi, false);
727 stop:
728 	mutex_unlock(&sbi->gc_mutex);
729 
730 	put_gc_inode(&ilist);
731 	return ret;
732 }
733 
734 void build_gc_manager(struct f2fs_sb_info *sbi)
735 {
736 	DIRTY_I(sbi)->v_ops = &default_v_ops;
737 }
738 
739 int __init create_gc_caches(void)
740 {
741 	winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
742 			sizeof(struct inode_entry));
743 	if (!winode_slab)
744 		return -ENOMEM;
745 	return 0;
746 }
747 
748 void destroy_gc_caches(void)
749 {
750 	kmem_cache_destroy(winode_slab);
751 }
752