Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2253 insertions, 0 deletions

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
new file mode 100644
index 0000000000..f550cdeaa6
--- /dev/null
+++ b/fs/f2fs/gc.c
@@ -0,0 +1,2253 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/f2fs/gc.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ */
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/f2fs_fs.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/sched/signal.h>
+#include <linux/random.h>
+#include <linux/sched/mm.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include "segment.h"
+#include "gc.h"
+#include "iostat.h"
+#include <trace/events/f2fs.h>
+
+static struct kmem_cache *victim_entry_slab;
+
+static unsigned int count_bits(const unsigned long *addr,
+				unsigned int offset, unsigned int len);
+
+static int gc_thread_func(void *data)
+{
+	struct f2fs_sb_info *sbi = data;
+	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
+	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
+	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
+	unsigned int wait_ms;
+	struct f2fs_gc_control gc_control = {
+		.victim_segno = NULL_SEGNO,
+		.should_migrate_blocks = false,
+		.err_gc_skipped = false };
+
+	wait_ms = gc_th->min_sleep_time;
+
+	set_freezable();
+	do {
+		bool sync_mode, foreground = false;
+
+		wait_event_interruptible_timeout(*wq,
+				kthread_should_stop() || freezing(current) ||
+				waitqueue_active(fggc_wq) ||
+				gc_th->gc_wake,
+				msecs_to_jiffies(wait_ms));
+
+		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
+			foreground = true;
+
+		/* give it a try one time */
+		if (gc_th->gc_wake)
+			gc_th->gc_wake = false;
+
+		if (try_to_freeze() || f2fs_readonly(sbi->sb)) {
+			stat_other_skip_bggc_count(sbi);
+			continue;
+		}
+		if (kthread_should_stop())
+			break;
+
+		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
+			increase_sleep_time(gc_th, &wait_ms);
+			stat_other_skip_bggc_count(sbi);
+			continue;
+		}
+
+		if (time_to_inject(sbi, FAULT_CHECKPOINT))
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_FAULT_INJECT);
+
+		if (!sb_start_write_trylock(sbi->sb)) {
+			stat_other_skip_bggc_count(sbi);
+			continue;
+		}
+
+		/*
+		 * [GC triggering condition]
+		 * 0. GC is not conducted currently.
+		 * 1. There are enough dirty segments.
+		 * 2. IO subsystem is idle by checking the # of writeback pages.
+		 * 3. IO subsystem is idle by checking the # of requests in
+		 *    bdev's request list.
+		 *
+		 * Note) We have to avoid triggering GCs frequently.
+		 * Because it is possible that some segments can be
+		 * invalidated soon after by user update or deletion.
+		 * So, I'd like to wait some time to collect dirty segments.
+		 */
+		if (sbi->gc_mode == GC_URGENT_HIGH ||
+				sbi->gc_mode == GC_URGENT_MID) {
+			wait_ms = gc_th->urgent_sleep_time;
+			f2fs_down_write(&sbi->gc_lock);
+			goto do_gc;
+		}
+
+		if (foreground) {
+			f2fs_down_write(&sbi->gc_lock);
+			goto do_gc;
+		} else if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
+			stat_other_skip_bggc_count(sbi);
+			goto next;
+		}
+
+		if (!is_idle(sbi, GC_TIME)) {
+			increase_sleep_time(gc_th, &wait_ms);
+			f2fs_up_write(&sbi->gc_lock);
+			stat_io_skip_bggc_count(sbi);
+			goto next;
+		}
+
+		if (has_enough_invalid_blocks(sbi))
+			decrease_sleep_time(gc_th, &wait_ms);
+		else
+			increase_sleep_time(gc_th, &wait_ms);
+do_gc:
+		stat_inc_gc_call_count(sbi, foreground ?
+					FOREGROUND : BACKGROUND);
+
+		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
+
+		/* foreground GC was been triggered via f2fs_balance_fs() */
+		if (foreground)
+			sync_mode = false;
+
+		gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
+		gc_control.no_bg_gc = foreground;
+		gc_control.nr_free_secs = foreground ? 1 : 0;
+
+		/* if return value is not zero, no victim was selected */
+		if (f2fs_gc(sbi, &gc_control)) {
+			/* don't bother wait_ms by foreground gc */
+			if (!foreground)
+				wait_ms = gc_th->no_gc_sleep_time;
+		} else {
+			/* reset wait_ms to default sleep time */
+			if (wait_ms == gc_th->no_gc_sleep_time)
+				wait_ms = gc_th->min_sleep_time;
+		}
+
+		if (foreground)
+			wake_up_all(&gc_th->fggc_wq);
+
+		trace_f2fs_background_gc(sbi->sb, wait_ms,
+				prefree_segments(sbi), free_segments(sbi));
+
+		/* balancing f2fs's metadata periodically */
+		f2fs_balance_fs_bg(sbi, true);
+next:
+		if (sbi->gc_mode != GC_NORMAL) {
+			spin_lock(&sbi->gc_remaining_trials_lock);
+			if (sbi->gc_remaining_trials) {
+				sbi->gc_remaining_trials--;
+				if (!sbi->gc_remaining_trials)
+					sbi->gc_mode = GC_NORMAL;
+			}
+			spin_unlock(&sbi->gc_remaining_trials_lock);
+		}
+		sb_end_write(sbi->sb);
+
+	} while (!kthread_should_stop());
+	return 0;
+}
+
+int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_gc_kthread *gc_th;
+	dev_t dev = sbi->sb->s_bdev->bd_dev;
+
+	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
+	if (!gc_th)
+		return -ENOMEM;
+
+	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
+	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
+	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
+	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
+
+	gc_th->gc_wake = false;
+
+	sbi->gc_thread = gc_th;
+	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
+	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
+	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
+			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
+	if (IS_ERR(gc_th->f2fs_gc_task)) {
+		int err = PTR_ERR(gc_th->f2fs_gc_task);
+
+		kfree(gc_th);
+		sbi->gc_thread = NULL;
+		return err;
+	}
+
+	return 0;
+}
+
+void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
+
+	if (!gc_th)
+		return;
+	kthread_stop(gc_th->f2fs_gc_task);
+	wake_up_all(&gc_th->fggc_wq);
+	kfree(gc_th);
+	sbi->gc_thread = NULL;
+}
+
+static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
+{
+	int gc_mode;
+
+	if (gc_type == BG_GC) {
+		if (sbi->am.atgc_enabled)
+			gc_mode = GC_AT;
+		else
+			gc_mode = GC_CB;
+	} else {
+		gc_mode = GC_GREEDY;
+	}
+
+	switch (sbi->gc_mode) {
+	case GC_IDLE_CB:
+		gc_mode = GC_CB;
+		break;
+	case GC_IDLE_GREEDY:
+	case GC_URGENT_HIGH:
+		gc_mode = GC_GREEDY;
+		break;
+	case GC_IDLE_AT:
+		gc_mode = GC_AT;
+		break;
+	}
+
+	return gc_mode;
+}
+
+static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
+			int type, struct victim_sel_policy *p)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+
+	if (p->alloc_mode == SSR) {
+		p->gc_mode = GC_GREEDY;
+		p->dirty_bitmap = dirty_i->dirty_segmap[type];
+		p->max_search = dirty_i->nr_dirty[type];
+		p->ofs_unit = 1;
+	} else if (p->alloc_mode == AT_SSR) {
+		p->gc_mode = GC_GREEDY;
+		p->dirty_bitmap = dirty_i->dirty_segmap[type];
+		p->max_search = dirty_i->nr_dirty[type];
+		p->ofs_unit = 1;
+	} else {
+		p->gc_mode = select_gc_type(sbi, gc_type);
+		p->ofs_unit = sbi->segs_per_sec;
+		if (__is_large_section(sbi)) {
+			p->dirty_bitmap = dirty_i->dirty_secmap;
+			p->max_search = count_bits(p->dirty_bitmap,
+						0, MAIN_SECS(sbi));
+		} else {
+			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
+			p->max_search = dirty_i->nr_dirty[DIRTY];
+		}
+	}
+
+	/*
+	 * adjust candidates range, should select all dirty segments for
+	 * foreground GC and urgent GC cases.
+	 */
+	if (gc_type != FG_GC &&
+			(sbi->gc_mode != GC_URGENT_HIGH) &&
+			(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
+			p->max_search > sbi->max_victim_search)
+		p->max_search = sbi->max_victim_search;
+
+	/* let's select beginning hot/small space first in no_heap mode*/
+	if (f2fs_need_rand_seg(sbi))
+		p->offset = get_random_u32_below(MAIN_SECS(sbi) * sbi->segs_per_sec);
+	else if (test_opt(sbi, NOHEAP) &&
+		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
+		p->offset = 0;
+	else
+		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
+}
+
+static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
+				struct victim_sel_policy *p)
+{
+	/* SSR allocates in a segment unit */
+	if (p->alloc_mode == SSR)
+		return sbi->blocks_per_seg;
+	else if (p->alloc_mode == AT_SSR)
+		return UINT_MAX;
+
+	/* LFS */
+	if (p->gc_mode == GC_GREEDY)
+		return 2 * sbi->blocks_per_seg * p->ofs_unit;
+	else if (p->gc_mode == GC_CB)
+		return UINT_MAX;
+	else if (p->gc_mode == GC_AT)
+		return UINT_MAX;
+	else /* No other gc_mode */
+		return 0;
+}
+
+static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	unsigned int secno;
+
+	/*
+	 * If the gc_type is FG_GC, we can select victim segments
+	 * selected by background GC before.
+	 * Those segments guarantee they have small valid blocks.
+	 */
+	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
+		if (sec_usage_check(sbi, secno))
+			continue;
+		clear_bit(secno, dirty_i->victim_secmap);
+		return GET_SEG_FROM_SEC(sbi, secno);
+	}
+	return NULL_SEGNO;
+}
+
+static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
+	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
+	unsigned long long mtime = 0;
+	unsigned int vblocks;
+	unsigned char age = 0;
+	unsigned char u;
+	unsigned int i;
+	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
+
+	for (i = 0; i < usable_segs_per_sec; i++)
+		mtime += get_seg_entry(sbi, start + i)->mtime;
+	vblocks = get_valid_blocks(sbi, segno, true);
+
+	mtime = div_u64(mtime, usable_segs_per_sec);
+	vblocks = div_u64(vblocks, usable_segs_per_sec);
+
+	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
+
+	/* Handle if the system time has changed by the user */
+	if (mtime < sit_i->min_mtime)
+		sit_i->min_mtime = mtime;
+	if (mtime > sit_i->max_mtime)
+		sit_i->max_mtime = mtime;
+	if (sit_i->max_mtime != sit_i->min_mtime)
+		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
+				sit_i->max_mtime - sit_i->min_mtime);
+
+	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
+}
+
+static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
+			unsigned int segno, struct victim_sel_policy *p)
+{
+	if (p->alloc_mode == SSR)
+		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
+
+	/* alloc_mode == LFS */
+	if (p->gc_mode == GC_GREEDY)
+		return get_valid_blocks(sbi, segno, true);
+	else if (p->gc_mode == GC_CB)
+		return get_cb_cost(sbi, segno);
+
+	f2fs_bug_on(sbi, 1);
+	return 0;
+}
+
+static unsigned int count_bits(const unsigned long *addr,
+				unsigned int offset, unsigned int len)
+{
+	unsigned int end = offset + len, sum = 0;
+
+	while (offset < end) {
+		if (test_bit(offset++, addr))
+			++sum;
+	}
+	return sum;
+}
+
+static bool f2fs_check_victim_tree(struct f2fs_sb_info *sbi,
+				struct rb_root_cached *root)
+{
+#ifdef CONFIG_F2FS_CHECK_FS
+	struct rb_node *cur = rb_first_cached(root), *next;
+	struct victim_entry *cur_ve, *next_ve;
+
+	while (cur) {
+		next = rb_next(cur);
+		if (!next)
+			return true;
+
+		cur_ve = rb_entry(cur, struct victim_entry, rb_node);
+		next_ve = rb_entry(next, struct victim_entry, rb_node);
+
+		if (cur_ve->mtime > next_ve->mtime) {
+			f2fs_info(sbi, "broken victim_rbtree, "
+				"cur_mtime(%llu) next_mtime(%llu)",
+				cur_ve->mtime, next_ve->mtime);
+			return false;
+		}
+		cur = next;
+	}
+#endif
+	return true;
+}
+
+static struct victim_entry *__lookup_victim_entry(struct f2fs_sb_info *sbi,
+					unsigned long long mtime)
+{
+	struct atgc_management *am = &sbi->am;
+	struct rb_node *node = am->root.rb_root.rb_node;
+	struct victim_entry *ve = NULL;
+
+	while (node) {
+		ve = rb_entry(node, struct victim_entry, rb_node);
+
+		if (mtime < ve->mtime)
+			node = node->rb_left;
+		else
+			node = node->rb_right;
+	}
+	return ve;
+}
+
+static struct victim_entry *__create_victim_entry(struct f2fs_sb_info *sbi,
+		unsigned long long mtime, unsigned int segno)
+{
+	struct atgc_management *am = &sbi->am;
+	struct victim_entry *ve;
+
+	ve =  f2fs_kmem_cache_alloc(victim_entry_slab, GFP_NOFS, true, NULL);
+
+	ve->mtime = mtime;
+	ve->segno = segno;
+
+	list_add_tail(&ve->list, &am->victim_list);
+	am->victim_count++;
+
+	return ve;
+}
+
+static void __insert_victim_entry(struct f2fs_sb_info *sbi,
+				unsigned long long mtime, unsigned int segno)
+{
+	struct atgc_management *am = &sbi->am;
+	struct rb_root_cached *root = &am->root;
+	struct rb_node **p = &root->rb_root.rb_node;
+	struct rb_node *parent = NULL;
+	struct victim_entry *ve;
+	bool left_most = true;
+
+	/* look up rb tree to find parent node */
+	while (*p) {
+		parent = *p;
+		ve = rb_entry(parent, struct victim_entry, rb_node);
+
+		if (mtime < ve->mtime) {
+			p = &(*p)->rb_left;
+		} else {
+			p = &(*p)->rb_right;
+			left_most = false;
+		}
+	}
+
+	ve = __create_victim_entry(sbi, mtime, segno);
+
+	rb_link_node(&ve->rb_node, parent, p);
+	rb_insert_color_cached(&ve->rb_node, root, left_most);
+}
+
+static void add_victim_entry(struct f2fs_sb_info *sbi,
+				struct victim_sel_policy *p, unsigned int segno)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
+	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
+	unsigned long long mtime = 0;
+	unsigned int i;
+
+	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
+		if (p->gc_mode == GC_AT &&
+			get_valid_blocks(sbi, segno, true) == 0)
+			return;
+	}
+
+	for (i = 0; i < sbi->segs_per_sec; i++)
+		mtime += get_seg_entry(sbi, start + i)->mtime;
+	mtime = div_u64(mtime, sbi->segs_per_sec);
+
+	/* Handle if the system time has changed by the user */
+	if (mtime < sit_i->min_mtime)
+		sit_i->min_mtime = mtime;
+	if (mtime > sit_i->max_mtime)
+		sit_i->max_mtime = mtime;
+	if (mtime < sit_i->dirty_min_mtime)
+		sit_i->dirty_min_mtime = mtime;
+	if (mtime > sit_i->dirty_max_mtime)
+		sit_i->dirty_max_mtime = mtime;
+
+	/* don't choose young section as candidate */
+	if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
+		return;
+
+	__insert_victim_entry(sbi, mtime, segno);
+}
+
+static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
+						struct victim_sel_policy *p)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct atgc_management *am = &sbi->am;
+	struct rb_root_cached *root = &am->root;
+	struct rb_node *node;
+	struct victim_entry *ve;
+	unsigned long long total_time;
+	unsigned long long age, u, accu;
+	unsigned long long max_mtime = sit_i->dirty_max_mtime;
+	unsigned long long min_mtime = sit_i->dirty_min_mtime;
+	unsigned int sec_blocks = CAP_BLKS_PER_SEC(sbi);
+	unsigned int vblocks;
+	unsigned int dirty_threshold = max(am->max_candidate_count,
+					am->candidate_ratio *
+					am->victim_count / 100);
+	unsigned int age_weight = am->age_weight;
+	unsigned int cost;
+	unsigned int iter = 0;
+
+	if (max_mtime < min_mtime)
+		return;
+
+	max_mtime += 1;
+	total_time = max_mtime - min_mtime;
+
+	accu = div64_u64(ULLONG_MAX, total_time);
+	accu = min_t(unsigned long long, div_u64(accu, 100),
+					DEFAULT_ACCURACY_CLASS);
+
+	node = rb_first_cached(root);
+next:
+	ve = rb_entry_safe(node, struct victim_entry, rb_node);
+	if (!ve)
+		return;
+
+	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
+		goto skip;
+
+	/* age = 10000 * x% * 60 */
+	age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
+								age_weight;
+
+	vblocks = get_valid_blocks(sbi, ve->segno, true);
+	f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
+
+	/* u = 10000 * x% * 40 */
+	u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
+							(100 - age_weight);
+
+	f2fs_bug_on(sbi, age + u >= UINT_MAX);
+
+	cost = UINT_MAX - (age + u);
+	iter++;
+
+	if (cost < p->min_cost ||
+			(cost == p->min_cost && age > p->oldest_age)) {
+		p->min_cost = cost;
+		p->oldest_age = age;
+		p->min_segno = ve->segno;
+	}
+skip:
+	if (iter < dirty_threshold) {
+		node = rb_next(node);
+		goto next;
+	}
+}
+
+/*
+ * select candidates around source section in range of
+ * [target - dirty_threshold, target + dirty_threshold]
+ */
+static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
+						struct victim_sel_policy *p)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct atgc_management *am = &sbi->am;
+	struct victim_entry *ve;
+	unsigned long long age;
+	unsigned long long max_mtime = sit_i->dirty_max_mtime;
+	unsigned long long min_mtime = sit_i->dirty_min_mtime;
+	unsigned int seg_blocks = sbi->blocks_per_seg;
+	unsigned int vblocks;
+	unsigned int dirty_threshold = max(am->max_candidate_count,
+					am->candidate_ratio *
+					am->victim_count / 100);
+	unsigned int cost, iter;
+	int stage = 0;
+
+	if (max_mtime < min_mtime)
+		return;
+	max_mtime += 1;
+next_stage:
+	iter = 0;
+	ve = __lookup_victim_entry(sbi, p->age);
+next_node:
+	if (!ve) {
+		if (stage++ == 0)
+			goto next_stage;
+		return;
+	}
+
+	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
+		goto skip_node;
+
+	age = max_mtime - ve->mtime;
+
+	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
+	f2fs_bug_on(sbi, !vblocks);
+
+	/* rare case */
+	if (vblocks == seg_blocks)
+		goto skip_node;
+
+	iter++;
+
+	age = max_mtime - abs(p->age - age);
+	cost = UINT_MAX - vblocks;
+
+	if (cost < p->min_cost ||
+			(cost == p->min_cost && age > p->oldest_age)) {
+		p->min_cost = cost;
+		p->oldest_age = age;
+		p->min_segno = ve->segno;
+	}
+skip_node:
+	if (iter < dirty_threshold) {
+		ve = rb_entry(stage == 0 ? rb_prev(&ve->rb_node) :
+					rb_next(&ve->rb_node),
+					struct victim_entry, rb_node);
+		goto next_node;
+	}
+
+	if (stage++ == 0)
+		goto next_stage;
+}
+
+static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
+						struct victim_sel_policy *p)
+{
+	f2fs_bug_on(sbi, !f2fs_check_victim_tree(sbi, &sbi->am.root));
+
+	if (p->gc_mode == GC_AT)
+		atgc_lookup_victim(sbi, p);
+	else if (p->alloc_mode == AT_SSR)
+		atssr_lookup_victim(sbi, p);
+	else
+		f2fs_bug_on(sbi, 1);
+}
+
+static void release_victim_entry(struct f2fs_sb_info *sbi)
+{
+	struct atgc_management *am = &sbi->am;
+	struct victim_entry *ve, *tmp;
+
+	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
+		list_del(&ve->list);
+		kmem_cache_free(victim_entry_slab, ve);
+		am->victim_count--;
+	}
+
+	am->root = RB_ROOT_CACHED;
+
+	f2fs_bug_on(sbi, am->victim_count);
+	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
+}
+
+static bool f2fs_pin_section(struct f2fs_sb_info *sbi, unsigned int segno)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
+
+	if (!dirty_i->enable_pin_section)
+		return false;
+	if (!test_and_set_bit(secno, dirty_i->pinned_secmap))
+		dirty_i->pinned_secmap_cnt++;
+	return true;
+}
+
+static bool f2fs_pinned_section_exists(struct dirty_seglist_info *dirty_i)
+{
+	return dirty_i->pinned_secmap_cnt;
+}
+
+static bool f2fs_section_is_pinned(struct dirty_seglist_info *dirty_i,
+						unsigned int secno)
+{
+	return dirty_i->enable_pin_section &&
+		f2fs_pinned_section_exists(dirty_i) &&
+		test_bit(secno, dirty_i->pinned_secmap);
+}
+
+static void f2fs_unpin_all_sections(struct f2fs_sb_info *sbi, bool enable)
+{
+	unsigned int bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
+
+	if (f2fs_pinned_section_exists(DIRTY_I(sbi))) {
+		memset(DIRTY_I(sbi)->pinned_secmap, 0, bitmap_size);
+		DIRTY_I(sbi)->pinned_secmap_cnt = 0;
+	}
+	DIRTY_I(sbi)->enable_pin_section = enable;
+}
+
+static int f2fs_gc_pinned_control(struct inode *inode, int gc_type,
+							unsigned int segno)
+{
+	if (!f2fs_is_pinned_file(inode))
+		return 0;
+	if (gc_type != FG_GC)
+		return -EBUSY;
+	if (!f2fs_pin_section(F2FS_I_SB(inode), segno))
+		f2fs_pin_file_control(inode, true);
+	return -EAGAIN;
+}
+
+/*
+ * This function is called from two paths.
+ * One is garbage collection and the other is SSR segment selection.
+ * When it is called during GC, it just gets a victim segment
+ * and it does not remove it from dirty seglist.
+ * When it is called from SSR segment selection, it finds a segment
+ * which has minimum valid blocks and removes it from dirty seglist.
+ */
+int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,
+			int gc_type, int type, char alloc_mode,
+			unsigned long long age)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	struct sit_info *sm = SIT_I(sbi);
+	struct victim_sel_policy p;
+	unsigned int secno, last_victim;
+	unsigned int last_segment;
+	unsigned int nsearched;
+	bool is_atgc;
+	int ret = 0;
+
+	mutex_lock(&dirty_i->seglist_lock);
+	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
+
+	p.alloc_mode = alloc_mode;
+	p.age = age;
+	p.age_threshold = sbi->am.age_threshold;
+
+retry:
+	select_policy(sbi, gc_type, type, &p);
+	p.min_segno = NULL_SEGNO;
+	p.oldest_age = 0;
+	p.min_cost = get_max_cost(sbi, &p);
+
+	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
+	nsearched = 0;
+
+	if (is_atgc)
+		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
+
+	if (*result != NULL_SEGNO) {
+		if (!get_valid_blocks(sbi, *result, false)) {
+			ret = -ENODATA;
+			goto out;
+		}
+
+		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
+			ret = -EBUSY;
+		else
+			p.min_segno = *result;
+		goto out;
+	}
+
+	ret = -ENODATA;
+	if (p.max_search == 0)
+		goto out;
+
+	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
+		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
+			p.min_segno = sbi->next_victim_seg[BG_GC];
+			*result = p.min_segno;
+			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
+			goto got_result;
+		}
+		if (gc_type == FG_GC &&
+				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
+			p.min_segno = sbi->next_victim_seg[FG_GC];
+			*result = p.min_segno;
+			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
+			goto got_result;
+		}
+	}
+
+	last_victim = sm->last_victim[p.gc_mode];
+	if (p.alloc_mode == LFS && gc_type == FG_GC) {
+		p.min_segno = check_bg_victims(sbi);
+		if (p.min_segno != NULL_SEGNO)
+			goto got_it;
+	}
+
+	while (1) {
+		unsigned long cost, *dirty_bitmap;
+		unsigned int unit_no, segno;
+
+		dirty_bitmap = p.dirty_bitmap;
+		unit_no = find_next_bit(dirty_bitmap,
+				last_segment / p.ofs_unit,
+				p.offset / p.ofs_unit);
+		segno = unit_no * p.ofs_unit;
+		if (segno >= last_segment) {
+			if (sm->last_victim[p.gc_mode]) {
+				last_segment =
+					sm->last_victim[p.gc_mode];
+				sm->last_victim[p.gc_mode] = 0;
+				p.offset = 0;
+				continue;
+			}
+			break;
+		}
+
+		p.offset = segno + p.ofs_unit;
+		nsearched++;
+
+#ifdef CONFIG_F2FS_CHECK_FS
+		/*
+		 * skip selecting the invalid segno (that is failed due to block
+		 * validity check failure during GC) to avoid endless GC loop in
+		 * such cases.
+		 */
+		if (test_bit(segno, sm->invalid_segmap))
+			goto next;
+#endif
+
+		secno = GET_SEC_FROM_SEG(sbi, segno);
+
+		if (sec_usage_check(sbi, secno))
+			goto next;
+
+		/* Don't touch checkpointed data */
+		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
+			if (p.alloc_mode == LFS) {
+				/*
+				 * LFS is set to find source section during GC.
+				 * The victim should have no checkpointed data.
+				 */
+				if (get_ckpt_valid_blocks(sbi, segno, true))
+					goto next;
+			} else {
+				/*
+				 * SSR | AT_SSR are set to find target segment
+				 * for writes which can be full by checkpointed
+				 * and newly written blocks.
+				 */
+				if (!f2fs_segment_has_free_slot(sbi, segno))
+					goto next;
+			}
+		}
+
+		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
+			goto next;
+
+		if (gc_type == FG_GC && f2fs_section_is_pinned(dirty_i, secno))
+			goto next;
+
+		if (is_atgc) {
+			add_victim_entry(sbi, &p, segno);
+			goto next;
+		}
+
+		cost = get_gc_cost(sbi, segno, &p);
+
+		if (p.min_cost > cost) {
+			p.min_segno = segno;
+			p.min_cost = cost;
+		}
+next:
+		if (nsearched >= p.max_search) {
+			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
+				sm->last_victim[p.gc_mode] =
+					last_victim + p.ofs_unit;
+			else
+				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
+			sm->last_victim[p.gc_mode] %=
+				(MAIN_SECS(sbi) * sbi->segs_per_sec);
+			break;
+		}
+	}
+
+	/* get victim for GC_AT/AT_SSR */
+	if (is_atgc) {
+		lookup_victim_by_age(sbi, &p);
+		release_victim_entry(sbi);
+	}
+
+	if (is_atgc && p.min_segno == NULL_SEGNO &&
+			sm->elapsed_time < p.age_threshold) {
+		p.age_threshold = 0;
+		goto retry;
+	}
+
+	if (p.min_segno != NULL_SEGNO) {
+got_it:
+		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
+got_result:
+		if (p.alloc_mode == LFS) {
+			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
+			if (gc_type == FG_GC)
+				sbi->cur_victim_sec = secno;
+			else
+				set_bit(secno, dirty_i->victim_secmap);
+		}
+		ret = 0;
+
+	}
+out:
+	if (p.min_segno != NULL_SEGNO)
+		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
+				sbi->cur_victim_sec,
+				prefree_segments(sbi), free_segments(sbi));
+	mutex_unlock(&dirty_i->seglist_lock);
+
+	return ret;
+}
+
+static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
+{
+	struct inode_entry *ie;
+
+	ie = radix_tree_lookup(&gc_list->iroot, ino);
+	if (ie)
+		return ie->inode;
+	return NULL;
+}
+
+static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
+{
+	struct inode_entry *new_ie;
+
+	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
+		iput(inode);
+		return;
+	}
+	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
+					GFP_NOFS, true, NULL);
+	new_ie->inode = inode;
+
+	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
+	list_add_tail(&new_ie->list, &gc_list->ilist);
+}
+
+static void put_gc_inode(struct gc_inode_list *gc_list)
+{
+	struct inode_entry *ie, *next_ie;
+
+	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
+		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
+		iput(ie->inode);
+		list_del(&ie->list);
+		kmem_cache_free(f2fs_inode_entry_slab, ie);
+	}
+}
+
+static int check_valid_map(struct f2fs_sb_info *sbi,
+				unsigned int segno, int offset)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct seg_entry *sentry;
+	int ret;
+
+	down_read(&sit_i->sentry_lock);
+	sentry = get_seg_entry(sbi, segno);
+	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
+	up_read(&sit_i->sentry_lock);
+	return ret;
+}
+
+/*
+ * This function compares node address got in summary with that in NAT.
+ * On validity, copy that node with cold status, otherwise (invalid node)
+ * ignore that.
+ */
+static int gc_node_segment(struct f2fs_sb_info *sbi,
+		struct f2fs_summary *sum, unsigned int segno, int gc_type)
+{
+	struct f2fs_summary *entry;
+	block_t start_addr;
+	int off;
+	int phase = 0;
+	bool fggc = (gc_type == FG_GC);
+	int submitted = 0;
+	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
+
+	start_addr = START_BLOCK(sbi, segno);
+
+next_step:
+	entry = sum;
+
+	if (fggc && phase == 2)
+		atomic_inc(&sbi->wb_sync_req[NODE]);
+
+	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
+		nid_t nid = le32_to_cpu(entry->nid);
+		struct page *node_page;
+		struct node_info ni;
+		int err;
+
+		/* stop BG_GC if there is not enough free sections. */
+		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
+			return submitted;
+
+		if (check_valid_map(sbi, segno, off) == 0)
+			continue;
+
+		if (phase == 0) {
+			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
+							META_NAT, true);
+			continue;
+		}
+
+		if (phase == 1) {
+			f2fs_ra_node_page(sbi, nid);
+			continue;
+		}
+
+		/* phase == 2 */
+		node_page = f2fs_get_node_page(sbi, nid);
+		if (IS_ERR(node_page))
+			continue;
+
+		/* block may become invalid during f2fs_get_node_page */
+		if (check_valid_map(sbi, segno, off) == 0) {
+			f2fs_put_page(node_page, 1);
+			continue;
+		}
+
+		if (f2fs_get_node_info(sbi, nid, &ni, false)) {
+			f2fs_put_page(node_page, 1);
+			continue;
+		}
+
+		if (ni.blk_addr != start_addr + off) {
+			f2fs_put_page(node_page, 1);
+			continue;
+		}
+
+		err = f2fs_move_node_page(node_page, gc_type);
+		if (!err && gc_type == FG_GC)
+			submitted++;
+		stat_inc_node_blk_count(sbi, 1, gc_type);
+	}
+
+	if (++phase < 3)
+		goto next_step;
+
+	if (fggc)
+		atomic_dec(&sbi->wb_sync_req[NODE]);
+	return submitted;
+}
+
+/*
+ * Calculate start block index indicating the given node offset.
+ * Be careful, caller should give this node offset only indicating direct node
+ * blocks. If any node offsets, which point the other types of node blocks such
+ * as indirect or double indirect node blocks, are given, it must be a caller's
+ * bug.
+ */
+block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
+{
+	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
+	unsigned int bidx;
+
+	if (node_ofs == 0)
+		return 0;
+
+	if (node_ofs <= 2) {
+		bidx = node_ofs - 1;
+	} else if (node_ofs <= indirect_blks) {
+		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
+
+		bidx = node_ofs - 2 - dec;
+	} else {
+		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
+
+		bidx = node_ofs - 5 - dec;
+	}
+	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
+}
+
+static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
+{
+	struct page *node_page;
+	nid_t nid;
+	unsigned int ofs_in_node, max_addrs, base;
+	block_t source_blkaddr;
+
+	nid = le32_to_cpu(sum->nid);
+	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
+
+	node_page = f2fs_get_node_page(sbi, nid);
+	if (IS_ERR(node_page))
+		return false;
+
+	if (f2fs_get_node_info(sbi, nid, dni, false)) {
+		f2fs_put_page(node_page, 1);
+		return false;
+	}
+
+	if (sum->version != dni->version) {
+		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
+			  __func__);
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+	}
+
+	if (f2fs_check_nid_range(sbi, dni->ino)) {
+		f2fs_put_page(node_page, 1);
+		return false;
+	}
+
+	if (IS_INODE(node_page)) {
+		base = offset_in_addr(F2FS_INODE(node_page));
+		max_addrs = DEF_ADDRS_PER_INODE;
+	} else {
+		base = 0;
+		max_addrs = DEF_ADDRS_PER_BLOCK;
+	}
+
+	if (base + ofs_in_node >= max_addrs) {
+		f2fs_err(sbi, "Inconsistent blkaddr offset: base:%u, ofs_in_node:%u, max:%u, ino:%u, nid:%u",
+			base, ofs_in_node, max_addrs, dni->ino, dni->nid);
+		f2fs_put_page(node_page, 1);
+		return false;
+	}
+
+	*nofs = ofs_of_node(node_page);
+	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
+	f2fs_put_page(node_page, 1);
+
+	if (source_blkaddr != blkaddr) {
+#ifdef CONFIG_F2FS_CHECK_FS
+		unsigned int segno = GET_SEGNO(sbi, blkaddr);
+		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
+
+		if (unlikely(check_valid_map(sbi, segno, offset))) {
+			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
+				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
+					 blkaddr, source_blkaddr, segno);
+				set_sbi_flag(sbi, SBI_NEED_FSCK);
+			}
+		}
+#endif
+		return false;
+	}
+	return true;
+}
+
+static int ra_data_block(struct inode *inode, pgoff_t index)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct address_space *mapping = inode->i_mapping;
+	struct dnode_of_data dn;
+	struct page *page;
+	struct f2fs_io_info fio = {
+		.sbi = sbi,
+		.ino = inode->i_ino,
+		.type = DATA,
+		.temp = COLD,
+		.op = REQ_OP_READ,
+		.op_flags = 0,
+		.encrypted_page = NULL,
+		.in_list = 0,
+		.retry = 0,
+	};
+	int err;
+
+	page = f2fs_grab_cache_page(mapping, index, true);
+	if (!page)
+		return -ENOMEM;
+
+	if (f2fs_lookup_read_extent_cache_block(inode, index,
+						&dn.data_blkaddr)) {
+		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
+						DATA_GENERIC_ENHANCE_READ))) {
+			err = -EFSCORRUPTED;
+			f2fs_handle_error(sbi, ERROR_INVALID_BLKADDR);
+			goto put_page;
+		}
+		goto got_it;
+	}
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
+	if (err)
+		goto put_page;
+	f2fs_put_dnode(&dn);
+
+	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
+		err = -ENOENT;
+		goto put_page;
+	}
+	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
+						DATA_GENERIC_ENHANCE))) {
+		err = -EFSCORRUPTED;
+		f2fs_handle_error(sbi, ERROR_INVALID_BLKADDR);
+		goto put_page;
+	}
+got_it:
+	/* read page */
+	fio.page = page;
+	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
+
+	/*
+	 * don't cache encrypted data into meta inode until previous dirty
+	 * data were writebacked to avoid racing between GC and flush.
+	 */
+	f2fs_wait_on_page_writeback(page, DATA, true, true);
+
+	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
+
+	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
+					dn.data_blkaddr,
+					FGP_LOCK | FGP_CREAT, GFP_NOFS);
+	if (!fio.encrypted_page) {
+		err = -ENOMEM;
+		goto put_page;
+	}
+
+	err = f2fs_submit_page_bio(&fio);
+	if (err)
+		goto put_encrypted_page;
+	f2fs_put_page(fio.encrypted_page, 0);
+	f2fs_put_page(page, 1);
+
+	f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
+	f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
+
+	return 0;
+put_encrypted_page:
+	f2fs_put_page(fio.encrypted_page, 1);
+put_page:
+	f2fs_put_page(page, 1);
+	return err;
+}
+
+/*
+ * Move data block via META_MAPPING while keeping locked data page.
+ * This can be used to move blocks, aka LBAs, directly on disk.
+ */
+static int move_data_block(struct inode *inode, block_t bidx,
+				int gc_type, unsigned int segno, int off)
+{
+	struct f2fs_io_info fio = {
+		.sbi = F2FS_I_SB(inode),
+		.ino = inode->i_ino,
+		.type = DATA,
+		.temp = COLD,
+		.op = REQ_OP_READ,
+		.op_flags = 0,
+		.encrypted_page = NULL,
+		.in_list = 0,
+		.retry = 0,
+	};
+	struct dnode_of_data dn;
+	struct f2fs_summary sum;
+	struct node_info ni;
+	struct page *page, *mpage;
+	block_t newaddr;
+	int err = 0;
+	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
+	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
+				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
+				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
+
+	/* do not read out */
+	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
+	if (!page)
+		return -ENOMEM;
+
+	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	err = f2fs_gc_pinned_control(inode, gc_type, segno);
+	if (err)
+		goto out;
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
+	if (err)
+		goto out;
+
+	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
+		ClearPageUptodate(page);
+		err = -ENOENT;
+		goto put_out;
+	}
+
+	/*
+	 * don't cache encrypted data into meta inode until previous dirty
+	 * data were writebacked to avoid racing between GC and flush.
+	 */
+	f2fs_wait_on_page_writeback(page, DATA, true, true);
+
+	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
+
+	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni, false);
+	if (err)
+		goto put_out;
+
+	/* read page */
+	fio.page = page;
+	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
+
+	if (lfs_mode)
+		f2fs_down_write(&fio.sbi->io_order_lock);
+
+	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
+					fio.old_blkaddr, false);
+	if (!mpage) {
+		err = -ENOMEM;
+		goto up_out;
+	}
+
+	fio.encrypted_page = mpage;
+
+	/* read source block in mpage */
+	if (!PageUptodate(mpage)) {
+		err = f2fs_submit_page_bio(&fio);
+		if (err) {
+			f2fs_put_page(mpage, 1);
+			goto up_out;
+		}
+
+		f2fs_update_iostat(fio.sbi, inode, FS_DATA_READ_IO,
+							F2FS_BLKSIZE);
+		f2fs_update_iostat(fio.sbi, NULL, FS_GDATA_READ_IO,
+							F2FS_BLKSIZE);
+
+		lock_page(mpage);
+		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
+						!PageUptodate(mpage))) {
+			err = -EIO;
+			f2fs_put_page(mpage, 1);
+			goto up_out;
+		}
+	}
+
+	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
+
+	/* allocate block address */
+	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
+				&sum, type, NULL);
+
+	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
+				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
+	if (!fio.encrypted_page) {
+		err = -ENOMEM;
+		f2fs_put_page(mpage, 1);
+		goto recover_block;
+	}
+
+	/* write target block */
+	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
+	memcpy(page_address(fio.encrypted_page),
+				page_address(mpage), PAGE_SIZE);
+	f2fs_put_page(mpage, 1);
+	invalidate_mapping_pages(META_MAPPING(fio.sbi),
+				fio.old_blkaddr, fio.old_blkaddr);
+	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
+
+	set_page_dirty(fio.encrypted_page);
+	if (clear_page_dirty_for_io(fio.encrypted_page))
+		dec_page_count(fio.sbi, F2FS_DIRTY_META);
+
+	set_page_writeback(fio.encrypted_page);
+
+	fio.op = REQ_OP_WRITE;
+	fio.op_flags = REQ_SYNC;
+	fio.new_blkaddr = newaddr;
+	f2fs_submit_page_write(&fio);
+	if (fio.retry) {
+		err = -EAGAIN;
+		if (PageWriteback(fio.encrypted_page))
+			end_page_writeback(fio.encrypted_page);
+		goto put_page_out;
+	}
+
+	f2fs_update_iostat(fio.sbi, NULL, FS_GC_DATA_IO, F2FS_BLKSIZE);
+
+	f2fs_update_data_blkaddr(&dn, newaddr);
+	set_inode_flag(inode, FI_APPEND_WRITE);
+	if (page->index == 0)
+		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
+put_page_out:
+	f2fs_put_page(fio.encrypted_page, 1);
+recover_block:
+	if (err)
+		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
+							true, true, true);
+up_out:
+	if (lfs_mode)
+		f2fs_up_write(&fio.sbi->io_order_lock);
+put_out:
+	f2fs_put_dnode(&dn);
+out:
+	f2fs_put_page(page, 1);
+	return err;
+}
+
+static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
+							unsigned int segno, int off)
+{
+	struct page *page;
+	int err = 0;
+
+	page = f2fs_get_lock_data_page(inode, bidx, true);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+
+	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	err = f2fs_gc_pinned_control(inode, gc_type, segno);
+	if (err)
+		goto out;
+
+	if (gc_type == BG_GC) {
+		if (PageWriteback(page)) {
+			err = -EAGAIN;
+			goto out;
+		}
+		set_page_dirty(page);
+		set_page_private_gcing(page);
+	} else {
+		struct f2fs_io_info fio = {
+			.sbi = F2FS_I_SB(inode),
+			.ino = inode->i_ino,
+			.type = DATA,
+			.temp = COLD,
+			.op = REQ_OP_WRITE,
+			.op_flags = REQ_SYNC,
+			.old_blkaddr = NULL_ADDR,
+			.page = page,
+			.encrypted_page = NULL,
+			.need_lock = LOCK_REQ,
+			.io_type = FS_GC_DATA_IO,
+		};
+		bool is_dirty = PageDirty(page);
+
+retry:
+		f2fs_wait_on_page_writeback(page, DATA, true, true);
+
+		set_page_dirty(page);
+		if (clear_page_dirty_for_io(page)) {
+			inode_dec_dirty_pages(inode);
+			f2fs_remove_dirty_inode(inode);
+		}
+
+		set_page_private_gcing(page);
+
+		err = f2fs_do_write_data_page(&fio);
+		if (err) {
+			clear_page_private_gcing(page);
+			if (err == -ENOMEM) {
+				memalloc_retry_wait(GFP_NOFS);
+				goto retry;
+			}
+			if (is_dirty)
+				set_page_dirty(page);
+		}
+	}
+out:
+	f2fs_put_page(page, 1);
+	return err;
+}
+
+/*
+ * This function tries to get parent node of victim data block, and identifies
+ * data block validity. If the block is valid, copy that with cold status and
+ * modify parent node.
+ * If the parent node is not valid or the data block address is different,
+ * the victim data block is ignored.
+ */
+static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
+		bool force_migrate)
+{
+	struct super_block *sb = sbi->sb;
+	struct f2fs_summary *entry;
+	block_t start_addr;
+	int off;
+	int phase = 0;
+	int submitted = 0;
+	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
+
+	start_addr = START_BLOCK(sbi, segno);
+
+next_step:
+	entry = sum;
+
+	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
+		struct page *data_page;
+		struct inode *inode;
+		struct node_info dni; /* dnode info for the data */
+		unsigned int ofs_in_node, nofs;
+		block_t start_bidx;
+		nid_t nid = le32_to_cpu(entry->nid);
+
+		/*
+		 * stop BG_GC if there is not enough free sections.
+		 * Or, stop GC if the segment becomes fully valid caused by
+		 * race condition along with SSR block allocation.
+		 */
+		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
+			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
+							CAP_BLKS_PER_SEC(sbi)))
+			return submitted;
+
+		if (check_valid_map(sbi, segno, off) == 0)
+			continue;
+
+		if (phase == 0) {
+			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
+							META_NAT, true);
+			continue;
+		}
+
+		if (phase == 1) {
+			f2fs_ra_node_page(sbi, nid);
+			continue;
+		}
+
+		/* Get an inode by ino with checking validity */
+		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
+			continue;
+
+		if (phase == 2) {
+			f2fs_ra_node_page(sbi, dni.ino);
+			continue;
+		}
+
+		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
+
+		if (phase == 3) {
+			int err;
+
+			inode = f2fs_iget(sb, dni.ino);
+			if (IS_ERR(inode) || is_bad_inode(inode) ||
+					special_file(inode->i_mode))
+				continue;
+
+			err = f2fs_gc_pinned_control(inode, gc_type, segno);
+			if (err == -EAGAIN) {
+				iput(inode);
+				return submitted;
+			}
+
+			if (!f2fs_down_write_trylock(
+				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
+				iput(inode);
+				sbi->skipped_gc_rwsem++;
+				continue;
+			}
+
+			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
+								ofs_in_node;
+
+			if (f2fs_post_read_required(inode)) {
+				int err = ra_data_block(inode, start_bidx);
+
+				f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+				if (err) {
+					iput(inode);
+					continue;
+				}
+				add_gc_inode(gc_list, inode);
+				continue;
+			}
+
+			data_page = f2fs_get_read_data_page(inode, start_bidx,
+							REQ_RAHEAD, true, NULL);
+			f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+			if (IS_ERR(data_page)) {
+				iput(inode);
+				continue;
+			}
+
+			f2fs_put_page(data_page, 0);
+			add_gc_inode(gc_list, inode);
+			continue;
+		}
+
+		/* phase 4 */
+		inode = find_gc_inode(gc_list, dni.ino);
+		if (inode) {
+			struct f2fs_inode_info *fi = F2FS_I(inode);
+			bool locked = false;
+			int err;
+
+			if (S_ISREG(inode->i_mode)) {
+				if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[WRITE])) {
+					sbi->skipped_gc_rwsem++;
+					continue;
+				}
+				if (!f2fs_down_write_trylock(
+						&fi->i_gc_rwsem[READ])) {
+					sbi->skipped_gc_rwsem++;
+					f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+					continue;
+				}
+				locked = true;
+
+				/* wait for all inflight aio data */
+				inode_dio_wait(inode);
+			}
+
+			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
+								+ ofs_in_node;
+			if (f2fs_post_read_required(inode))
+				err = move_data_block(inode, start_bidx,
+							gc_type, segno, off);
+			else
+				err = move_data_page(inode, start_bidx, gc_type,
+								segno, off);
+
+			if (!err && (gc_type == FG_GC ||
+					f2fs_post_read_required(inode)))
+				submitted++;
+
+			if (locked) {
+				f2fs_up_write(&fi->i_gc_rwsem[READ]);
+				f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+			}
+
+			stat_inc_data_blk_count(sbi, 1, gc_type);
+		}
+	}
+
+	if (++phase < 5)
+		goto next_step;
+
+	return submitted;
+}
+
+static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
+			int gc_type)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	int ret;
+
+	down_write(&sit_i->sentry_lock);
+	ret = f2fs_get_victim(sbi, victim, gc_type, NO_CHECK_TYPE, LFS, 0);
+	up_write(&sit_i->sentry_lock);
+	return ret;
+}
+
+static int do_garbage_collect(struct f2fs_sb_info *sbi,
+				unsigned int start_segno,
+				struct gc_inode_list *gc_list, int gc_type,
+				bool force_migrate)
+{
+	struct page *sum_page;
+	struct f2fs_summary_block *sum;
+	struct blk_plug plug;
+	unsigned int segno = start_segno;
+	unsigned int end_segno = start_segno + sbi->segs_per_sec;
+	int seg_freed = 0, migrated = 0;
+	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
+						SUM_TYPE_DATA : SUM_TYPE_NODE;
+	unsigned char data_type = (type == SUM_TYPE_DATA) ? DATA : NODE;
+	int submitted = 0;
+
+	if (__is_large_section(sbi))
+		end_segno = rounddown(end_segno, sbi->segs_per_sec);
+
+	/*
+	 * zone-capacity can be less than zone-size in zoned devices,
+	 * resulting in less than expected usable segments in the zone,
+	 * calculate the end segno in the zone which can be garbage collected
+	 */
+	if (f2fs_sb_has_blkzoned(sbi))
+		end_segno -= sbi->segs_per_sec -
+					f2fs_usable_segs_in_sec(sbi, segno);
+
+	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
+
+	/* readahead multi ssa blocks those have contiguous address */
+	if (__is_large_section(sbi))
+		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
+					end_segno - segno, META_SSA, true);
+
+	/* reference all summary page */
+	while (segno < end_segno) {
+		sum_page = f2fs_get_sum_page(sbi, segno++);
+		if (IS_ERR(sum_page)) {
+			int err = PTR_ERR(sum_page);
+
+			end_segno = segno - 1;
+			for (segno = start_segno; segno < end_segno; segno++) {
+				sum_page = find_get_page(META_MAPPING(sbi),
+						GET_SUM_BLOCK(sbi, segno));
+				f2fs_put_page(sum_page, 0);
+				f2fs_put_page(sum_page, 0);
+			}
+			return err;
+		}
+		unlock_page(sum_page);
+	}
+
+	blk_start_plug(&plug);
+
+	for (segno = start_segno; segno < end_segno; segno++) {
+
+		/* find segment summary of victim */
+		sum_page = find_get_page(META_MAPPING(sbi),
+					GET_SUM_BLOCK(sbi, segno));
+		f2fs_put_page(sum_page, 0);
+
+		if (get_valid_blocks(sbi, segno, false) == 0)
+			goto freed;
+		if (gc_type == BG_GC && __is_large_section(sbi) &&
+				migrated >= sbi->migration_granularity)
+			goto skip;
+		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
+			goto skip;
+
+		sum = page_address(sum_page);
+		if (type != GET_SUM_TYPE((&sum->footer))) {
+			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
+				 segno, type, GET_SUM_TYPE((&sum->footer)));
+			set_sbi_flag(sbi, SBI_NEED_FSCK);
+			f2fs_stop_checkpoint(sbi, false,
+				STOP_CP_REASON_CORRUPTED_SUMMARY);
+			goto skip;
+		}
+
+		/*
+		 * this is to avoid deadlock:
+		 * - lock_page(sum_page)         - f2fs_replace_block
+		 *  - check_valid_map()            - down_write(sentry_lock)
+		 *   - down_read(sentry_lock)     - change_curseg()
+		 *                                  - lock_page(sum_page)
+		 */
+		if (type == SUM_TYPE_NODE)
+			submitted += gc_node_segment(sbi, sum->entries, segno,
+								gc_type);
+		else
+			submitted += gc_data_segment(sbi, sum->entries, gc_list,
+							segno, gc_type,
+							force_migrate);
+
+		stat_inc_gc_seg_count(sbi, data_type, gc_type);
+		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
+		migrated++;
+
+freed:
+		if (gc_type == FG_GC &&
+				get_valid_blocks(sbi, segno, false) == 0)
+			seg_freed++;
+
+		if (__is_large_section(sbi))
+			sbi->next_victim_seg[gc_type] =
+				(segno + 1 < end_segno) ? segno + 1 : NULL_SEGNO;
+skip:
+		f2fs_put_page(sum_page, 0);
+	}
+
+	if (submitted)
+		f2fs_submit_merged_write(sbi, data_type);
+
+	blk_finish_plug(&plug);
+
+	if (migrated)
+		stat_inc_gc_sec_count(sbi, data_type, gc_type);
+
+	return seg_freed;
+}
+
+int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
+{
+	int gc_type = gc_control->init_gc_type;
+	unsigned int segno = gc_control->victim_segno;
+	int sec_freed = 0, seg_freed = 0, total_freed = 0, total_sec_freed = 0;
+	int ret = 0;
+	struct cp_control cpc;
+	struct gc_inode_list gc_list = {
+		.ilist = LIST_HEAD_INIT(gc_list.ilist),
+		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
+	};
+	unsigned int skipped_round = 0, round = 0;
+	unsigned int upper_secs;
+
+	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
+				gc_control->nr_free_secs,
+				get_pages(sbi, F2FS_DIRTY_NODES),
+				get_pages(sbi, F2FS_DIRTY_DENTS),
+				get_pages(sbi, F2FS_DIRTY_IMETA),
+				free_sections(sbi),
+				free_segments(sbi),
+				reserved_segments(sbi),
+				prefree_segments(sbi));
+
+	cpc.reason = __get_cp_reason(sbi);
+gc_more:
+	sbi->skipped_gc_rwsem = 0;
+	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
+		ret = -EINVAL;
+		goto stop;
+	}
+	if (unlikely(f2fs_cp_error(sbi))) {
+		ret = -EIO;
+		goto stop;
+	}
+
+	/* Let's run FG_GC, if we don't have enough space. */
+	if (has_not_enough_free_secs(sbi, 0, 0)) {
+		gc_type = FG_GC;
+
+		/*
+		 * For example, if there are many prefree_segments below given
+		 * threshold, we can make them free by checkpoint. Then, we
+		 * secure free segments which doesn't need fggc any more.
+		 */
+		if (prefree_segments(sbi)) {
+			stat_inc_cp_call_count(sbi, TOTAL_CALL);
+			ret = f2fs_write_checkpoint(sbi, &cpc);
+			if (ret)
+				goto stop;
+			/* Reset due to checkpoint */
+			sec_freed = 0;
+		}
+	}
+
+	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
+	if (gc_type == BG_GC && gc_control->no_bg_gc) {
+		ret = -EINVAL;
+		goto stop;
+	}
+retry:
+	ret = __get_victim(sbi, &segno, gc_type);
+	if (ret) {
+		/* allow to search victim from sections has pinned data */
+		if (ret == -ENODATA && gc_type == FG_GC &&
+				f2fs_pinned_section_exists(DIRTY_I(sbi))) {
+			f2fs_unpin_all_sections(sbi, false);
+			goto retry;
+		}
+		goto stop;
+	}
+
+	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
+				gc_control->should_migrate_blocks);
+	total_freed += seg_freed;
+
+	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno)) {
+		sec_freed++;
+		total_sec_freed++;
+	}
+
+	if (gc_type == FG_GC) {
+		sbi->cur_victim_sec = NULL_SEGNO;
+
+		if (has_enough_free_secs(sbi, sec_freed, 0)) {
+			if (!gc_control->no_bg_gc &&
+			    total_sec_freed < gc_control->nr_free_secs)
+				goto go_gc_more;
+			goto stop;
+		}
+		if (sbi->skipped_gc_rwsem)
+			skipped_round++;
+		round++;
+		if (skipped_round > MAX_SKIP_GC_COUNT &&
+				skipped_round * 2 >= round) {
+			stat_inc_cp_call_count(sbi, TOTAL_CALL);
+			ret = f2fs_write_checkpoint(sbi, &cpc);
+			goto stop;
+		}
+	} else if (has_enough_free_secs(sbi, 0, 0)) {
+		goto stop;
+	}
+
+	__get_secs_required(sbi, NULL, &upper_secs, NULL);
+
+	/*
+	 * Write checkpoint to reclaim prefree segments.
+	 * We need more three extra sections for writer's data/node/dentry.
+	 */
+	if (free_sections(sbi) <= upper_secs + NR_GC_CHECKPOINT_SECS &&
+				prefree_segments(sbi)) {
+		stat_inc_cp_call_count(sbi, TOTAL_CALL);
+		ret = f2fs_write_checkpoint(sbi, &cpc);
+		if (ret)
+			goto stop;
+		/* Reset due to checkpoint */
+		sec_freed = 0;
+	}
+go_gc_more:
+	segno = NULL_SEGNO;
+	goto gc_more;
+
+stop:
+	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
+	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = gc_control->victim_segno;
+
+	if (gc_type == FG_GC)
+		f2fs_unpin_all_sections(sbi, true);
+
+	trace_f2fs_gc_end(sbi->sb, ret, total_freed, total_sec_freed,
+				get_pages(sbi, F2FS_DIRTY_NODES),
+				get_pages(sbi, F2FS_DIRTY_DENTS),
+				get_pages(sbi, F2FS_DIRTY_IMETA),
+				free_sections(sbi),
+				free_segments(sbi),
+				reserved_segments(sbi),
+				prefree_segments(sbi));
+
+	f2fs_up_write(&sbi->gc_lock);
+
+	put_gc_inode(&gc_list);
+
+	if (gc_control->err_gc_skipped && !ret)
+		ret = total_sec_freed ? 0 : -EAGAIN;
+	return ret;
+}
+
+int __init f2fs_create_garbage_collection_cache(void)
+{
+	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
+					sizeof(struct victim_entry));
+	return victim_entry_slab ? 0 : -ENOMEM;
+}
+
+void f2fs_destroy_garbage_collection_cache(void)
+{
+	kmem_cache_destroy(victim_entry_slab);
+}
+
+static void init_atgc_management(struct f2fs_sb_info *sbi)
+{
+	struct atgc_management *am = &sbi->am;
+
+	if (test_opt(sbi, ATGC) &&
+		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
+		am->atgc_enabled = true;
+
+	am->root = RB_ROOT_CACHED;
+	INIT_LIST_HEAD(&am->victim_list);
+	am->victim_count = 0;
+
+	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
+	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
+	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
+	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
+}
+
+void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
+{
+	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
+
+	/* give warm/cold data area from slower device */
+	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
+		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
+				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
+
+	init_atgc_management(sbi);
+}
+
+static int free_segment_range(struct f2fs_sb_info *sbi,
+				unsigned int secs, bool gc_only)
+{
+	unsigned int segno, next_inuse, start, end;
+	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
+	int gc_mode, gc_type;
+	int err = 0;
+	int type;
+
+	/* Force block allocation for GC */
+	MAIN_SECS(sbi) -= secs;
+	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
+	end = MAIN_SEGS(sbi) - 1;
+
+	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
+	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
+		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
+			SIT_I(sbi)->last_victim[gc_mode] = 0;
+
+	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
+		if (sbi->next_victim_seg[gc_type] >= start)
+			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
+	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
+
+	/* Move out cursegs from the target range */
+	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++)
+		f2fs_allocate_segment_for_resize(sbi, type, start, end);
+
+	/* do GC to move out valid blocks in the range */
+	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
+		struct gc_inode_list gc_list = {
+			.ilist = LIST_HEAD_INIT(gc_list.ilist),
+			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
+		};
+
+		do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
+		put_gc_inode(&gc_list);
+
+		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
+			err = -EAGAIN;
+			goto out;
+		}
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			goto out;
+		}
+	}
+	if (gc_only)
+		goto out;
+
+	stat_inc_cp_call_count(sbi, TOTAL_CALL);
+	err = f2fs_write_checkpoint(sbi, &cpc);
+	if (err)
+		goto out;
+
+	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
+	if (next_inuse <= end) {
+		f2fs_err(sbi, "segno %u should be free but still inuse!",
+			 next_inuse);
+		f2fs_bug_on(sbi, 1);
+	}
+out:
+	MAIN_SECS(sbi) += secs;
+	return err;
+}
+
+static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
+{
+	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
+	int section_count;
+	int segment_count;
+	int segment_count_main;
+	long long block_count;
+	int segs = secs * sbi->segs_per_sec;
+
+	f2fs_down_write(&sbi->sb_lock);
+
+	section_count = le32_to_cpu(raw_sb->section_count);
+	segment_count = le32_to_cpu(raw_sb->segment_count);
+	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
+	block_count = le64_to_cpu(raw_sb->block_count);
+
+	raw_sb->section_count = cpu_to_le32(section_count + secs);
+	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
+	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
+	raw_sb->block_count = cpu_to_le64(block_count +
+					(long long)segs * sbi->blocks_per_seg);
+	if (f2fs_is_multi_device(sbi)) {
+		int last_dev = sbi->s_ndevs - 1;
+		int dev_segs =
+			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
+
+		raw_sb->devs[last_dev].total_segments =
+						cpu_to_le32(dev_segs + segs);
+	}
+
+	f2fs_up_write(&sbi->sb_lock);
+}
+
+static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
+{
+	int segs = secs * sbi->segs_per_sec;
+	long long blks = (long long)segs * sbi->blocks_per_seg;
+	long long user_block_count =
+				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
+
+	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
+	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
+	MAIN_SECS(sbi) += secs;
+	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
+	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
+	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
+
+	if (f2fs_is_multi_device(sbi)) {
+		int last_dev = sbi->s_ndevs - 1;
+
+		FDEV(last_dev).total_segments =
+				(int)FDEV(last_dev).total_segments + segs;
+		FDEV(last_dev).end_blk =
+				(long long)FDEV(last_dev).end_blk + blks;
+#ifdef CONFIG_BLK_DEV_ZONED
+		FDEV(last_dev).nr_blkz = FDEV(last_dev).nr_blkz +
+					div_u64(blks, sbi->blocks_per_blkz);
+#endif
+	}
+}
+
+int f2fs_resize_fs(struct file *filp, __u64 block_count)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(filp));
+	__u64 old_block_count, shrunk_blocks;
+	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
+	unsigned int secs;
+	int err = 0;
+	__u32 rem;
+
+	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
+	if (block_count > old_block_count)
+		return -EINVAL;
+
+	if (f2fs_is_multi_device(sbi)) {
+		int last_dev = sbi->s_ndevs - 1;
+		__u64 last_segs = FDEV(last_dev).total_segments;
+
+		if (block_count + last_segs * sbi->blocks_per_seg <=
+								old_block_count)
+			return -EINVAL;
+	}
+
+	/* new fs size should align to section size */
+	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
+	if (rem)
+		return -EINVAL;
+
+	if (block_count == old_block_count)
+		return 0;
+
+	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+		f2fs_err(sbi, "Should run fsck to repair first.");
+		return -EFSCORRUPTED;
+	}
+
+	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
+		f2fs_err(sbi, "Checkpoint should be enabled.");
+		return -EINVAL;
+	}
+
+	err = mnt_want_write_file(filp);
+	if (err)
+		return err;
+
+	shrunk_blocks = old_block_count - block_count;
+	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
+
+	/* stop other GC */
+	if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
+		err = -EAGAIN;
+		goto out_drop_write;
+	}
+
+	/* stop CP to protect MAIN_SEC in free_segment_range */
+	f2fs_lock_op(sbi);
+
+	spin_lock(&sbi->stat_lock);
+	if (shrunk_blocks + valid_user_blocks(sbi) +
+		sbi->current_reserved_blocks + sbi->unusable_block_count +
+		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
+		err = -ENOSPC;
+	spin_unlock(&sbi->stat_lock);
+
+	if (err)
+		goto out_unlock;
+
+	err = free_segment_range(sbi, secs, true);
+
+out_unlock:
+	f2fs_unlock_op(sbi);
+	f2fs_up_write(&sbi->gc_lock);
+out_drop_write:
+	mnt_drop_write_file(filp);
+	if (err)
+		return err;
+
+	err = freeze_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
+	if (err)
+		return err;
+
+	if (f2fs_readonly(sbi->sb)) {
+		err = thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
+		if (err)
+			return err;
+		return -EROFS;
+	}
+
+	f2fs_down_write(&sbi->gc_lock);
+	f2fs_down_write(&sbi->cp_global_sem);
+
+	spin_lock(&sbi->stat_lock);
+	if (shrunk_blocks + valid_user_blocks(sbi) +
+		sbi->current_reserved_blocks + sbi->unusable_block_count +
+		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
+		err = -ENOSPC;
+	else
+		sbi->user_block_count -= shrunk_blocks;
+	spin_unlock(&sbi->stat_lock);
+	if (err)
+		goto out_err;
+
+	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
+	err = free_segment_range(sbi, secs, false);
+	if (err)
+		goto recover_out;
+
+	update_sb_metadata(sbi, -secs);
+
+	err = f2fs_commit_super(sbi, false);
+	if (err) {
+		update_sb_metadata(sbi, secs);
+		goto recover_out;
+	}
+
+	update_fs_metadata(sbi, -secs);
+	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
+	set_sbi_flag(sbi, SBI_IS_DIRTY);
+
+	stat_inc_cp_call_count(sbi, TOTAL_CALL);
+	err = f2fs_write_checkpoint(sbi, &cpc);
+	if (err) {
+		update_fs_metadata(sbi, secs);
+		update_sb_metadata(sbi, secs);
+		f2fs_commit_super(sbi, false);
+	}
+recover_out:
+	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
+	if (err) {
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
+
+		spin_lock(&sbi->stat_lock);
+		sbi->user_block_count += shrunk_blocks;
+		spin_unlock(&sbi->stat_lock);
+	}
+out_err:
+	f2fs_up_write(&sbi->cp_global_sem);
+	f2fs_up_write(&sbi->gc_lock);
+	thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
+	return err;
+}