Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 4397 insertions, 0 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
new file mode 100644
index 000000000..6fbf04713
--- /dev/null
+++ b/fs/f2fs/segment.c
@@ -0,0 +1,4397 @@
+/*
+ * fs/f2fs/segment.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/fs.h>
+#include <linux/f2fs_fs.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/prefetch.h>
+#include <linux/kthread.h>
+#include <linux/swap.h>
+#include <linux/timer.h>
+#include <linux/freezer.h>
+#include <linux/sched/signal.h>
+
+#include "f2fs.h"
+#include "segment.h"
+#include "node.h"
+#include "gc.h"
+#include "trace.h"
+#include <trace/events/f2fs.h>
+
+#define __reverse_ffz(x) __reverse_ffs(~(x))
+
+static struct kmem_cache *discard_entry_slab;
+static struct kmem_cache *discard_cmd_slab;
+static struct kmem_cache *sit_entry_set_slab;
+static struct kmem_cache *inmem_entry_slab;
+
+static unsigned long __reverse_ulong(unsigned char *str)
+{
+	unsigned long tmp = 0;
+	int shift = 24, idx = 0;
+
+#if BITS_PER_LONG == 64
+	shift = 56;
+#endif
+	while (shift >= 0) {
+		tmp |= (unsigned long)str[idx++] << shift;
+		shift -= BITS_PER_BYTE;
+	}
+	return tmp;
+}
+
+/*
+ * __reverse_ffs is copied from include/asm-generic/bitops/__ffs.h since
+ * MSB and LSB are reversed in a byte by f2fs_set_bit.
+ */
+static inline unsigned long __reverse_ffs(unsigned long word)
+{
+	int num = 0;
+
+#if BITS_PER_LONG == 64
+	if ((word & 0xffffffff00000000UL) == 0)
+		num += 32;
+	else
+		word >>= 32;
+#endif
+	if ((word & 0xffff0000) == 0)
+		num += 16;
+	else
+		word >>= 16;
+
+	if ((word & 0xff00) == 0)
+		num += 8;
+	else
+		word >>= 8;
+
+	if ((word & 0xf0) == 0)
+		num += 4;
+	else
+		word >>= 4;
+
+	if ((word & 0xc) == 0)
+		num += 2;
+	else
+		word >>= 2;
+
+	if ((word & 0x2) == 0)
+		num += 1;
+	return num;
+}
+
+/*
+ * __find_rev_next(_zero)_bit is copied from lib/find_next_bit.c because
+ * f2fs_set_bit makes MSB and LSB reversed in a byte.
+ * @size must be integral times of unsigned long.
+ * Example:
+ *                             MSB <--> LSB
+ *   f2fs_set_bit(0, bitmap) => 1000 0000
+ *   f2fs_set_bit(7, bitmap) => 0000 0001
+ */
+static unsigned long __find_rev_next_bit(const unsigned long *addr,
+			unsigned long size, unsigned long offset)
+{
+	const unsigned long *p = addr + BIT_WORD(offset);
+	unsigned long result = size;
+	unsigned long tmp;
+
+	if (offset >= size)
+		return size;
+
+	size -= (offset & ~(BITS_PER_LONG - 1));
+	offset %= BITS_PER_LONG;
+
+	while (1) {
+		if (*p == 0)
+			goto pass;
+
+		tmp = __reverse_ulong((unsigned char *)p);
+
+		tmp &= ~0UL >> offset;
+		if (size < BITS_PER_LONG)
+			tmp &= (~0UL << (BITS_PER_LONG - size));
+		if (tmp)
+			goto found;
+pass:
+		if (size <= BITS_PER_LONG)
+			break;
+		size -= BITS_PER_LONG;
+		offset = 0;
+		p++;
+	}
+	return result;
+found:
+	return result - size + __reverse_ffs(tmp);
+}
+
+static unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
+			unsigned long size, unsigned long offset)
+{
+	const unsigned long *p = addr + BIT_WORD(offset);
+	unsigned long result = size;
+	unsigned long tmp;
+
+	if (offset >= size)
+		return size;
+
+	size -= (offset & ~(BITS_PER_LONG - 1));
+	offset %= BITS_PER_LONG;
+
+	while (1) {
+		if (*p == ~0UL)
+			goto pass;
+
+		tmp = __reverse_ulong((unsigned char *)p);
+
+		if (offset)
+			tmp |= ~0UL << (BITS_PER_LONG - offset);
+		if (size < BITS_PER_LONG)
+			tmp |= ~0UL >> size;
+		if (tmp != ~0UL)
+			goto found;
+pass:
+		if (size <= BITS_PER_LONG)
+			break;
+		size -= BITS_PER_LONG;
+		offset = 0;
+		p++;
+	}
+	return result;
+found:
+	return result - size + __reverse_ffz(tmp);
+}
+
+bool f2fs_need_SSR(struct f2fs_sb_info *sbi)
+{
+	int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
+	int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
+	int imeta_secs = get_blocktype_secs(sbi, F2FS_DIRTY_IMETA);
+
+	if (test_opt(sbi, LFS))
+		return false;
+	if (sbi->gc_mode == GC_URGENT)
+		return true;
+
+	return free_sections(sbi) <= (node_secs + 2 * dent_secs + imeta_secs +
+			SM_I(sbi)->min_ssr_sections + reserved_sections(sbi));
+}
+
+void f2fs_register_inmem_page(struct inode *inode, struct page *page)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct inmem_pages *new;
+
+	f2fs_trace_pid(page);
+
+	set_page_private(page, (unsigned long)ATOMIC_WRITTEN_PAGE);
+	SetPagePrivate(page);
+
+	new = f2fs_kmem_cache_alloc(inmem_entry_slab, GFP_NOFS);
+
+	/* add atomic page indices to the list */
+	new->page = page;
+	INIT_LIST_HEAD(&new->list);
+
+	/* increase reference count with clean state */
+	mutex_lock(&fi->inmem_lock);
+	get_page(page);
+	list_add_tail(&new->list, &fi->inmem_pages);
+	spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
+	if (list_empty(&fi->inmem_ilist))
+		list_add_tail(&fi->inmem_ilist, &sbi->inode_list[ATOMIC_FILE]);
+	spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
+	inc_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
+	mutex_unlock(&fi->inmem_lock);
+
+	trace_f2fs_register_inmem_page(page, INMEM);
+}
+
+static int __revoke_inmem_pages(struct inode *inode,
+				struct list_head *head, bool drop, bool recover,
+				bool trylock)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct inmem_pages *cur, *tmp;
+	int err = 0;
+
+	list_for_each_entry_safe(cur, tmp, head, list) {
+		struct page *page = cur->page;
+
+		if (drop)
+			trace_f2fs_commit_inmem_page(page, INMEM_DROP);
+
+		if (trylock) {
+			/*
+			 * to avoid deadlock in between page lock and
+			 * inmem_lock.
+			 */
+			if (!trylock_page(page))
+				continue;
+		} else {
+			lock_page(page);
+		}
+
+		f2fs_wait_on_page_writeback(page, DATA, true);
+
+		if (recover) {
+			struct dnode_of_data dn;
+			struct node_info ni;
+
+			trace_f2fs_commit_inmem_page(page, INMEM_REVOKE);
+retry:
+			set_new_dnode(&dn, inode, NULL, NULL, 0);
+			err = f2fs_get_dnode_of_data(&dn, page->index,
+								LOOKUP_NODE);
+			if (err) {
+				if (err == -ENOMEM) {
+					congestion_wait(BLK_RW_ASYNC, HZ/50);
+					cond_resched();
+					goto retry;
+				}
+				err = -EAGAIN;
+				goto next;
+			}
+
+			err = f2fs_get_node_info(sbi, dn.nid, &ni);
+			if (err) {
+				f2fs_put_dnode(&dn);
+				return err;
+			}
+
+			if (cur->old_addr == NEW_ADDR) {
+				f2fs_invalidate_blocks(sbi, dn.data_blkaddr);
+				f2fs_update_data_blkaddr(&dn, NEW_ADDR);
+			} else
+				f2fs_replace_block(sbi, &dn, dn.data_blkaddr,
+					cur->old_addr, ni.version, true, true);
+			f2fs_put_dnode(&dn);
+		}
+next:
+		/* we don't need to invalidate this in the sccessful status */
+		if (drop || recover) {
+			ClearPageUptodate(page);
+			clear_cold_data(page);
+		}
+		set_page_private(page, 0);
+		ClearPagePrivate(page);
+		f2fs_put_page(page, 1);
+
+		list_del(&cur->list);
+		kmem_cache_free(inmem_entry_slab, cur);
+		dec_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
+	}
+	return err;
+}
+
+void f2fs_drop_inmem_pages_all(struct f2fs_sb_info *sbi, bool gc_failure)
+{
+	struct list_head *head = &sbi->inode_list[ATOMIC_FILE];
+	struct inode *inode;
+	struct f2fs_inode_info *fi;
+next:
+	spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
+	if (list_empty(head)) {
+		spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
+		return;
+	}
+	fi = list_first_entry(head, struct f2fs_inode_info, inmem_ilist);
+	inode = igrab(&fi->vfs_inode);
+	spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
+
+	if (inode) {
+		if (gc_failure) {
+			if (fi->i_gc_failures[GC_FAILURE_ATOMIC])
+				goto drop;
+			goto skip;
+		}
+drop:
+		set_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
+		f2fs_drop_inmem_pages(inode);
+		iput(inode);
+	}
+skip:
+	congestion_wait(BLK_RW_ASYNC, HZ/50);
+	cond_resched();
+	goto next;
+}
+
+void f2fs_drop_inmem_pages(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+
+	while (!list_empty(&fi->inmem_pages)) {
+		mutex_lock(&fi->inmem_lock);
+		__revoke_inmem_pages(inode, &fi->inmem_pages,
+						true, false, true);
+
+		if (list_empty(&fi->inmem_pages)) {
+			spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
+			if (!list_empty(&fi->inmem_ilist))
+				list_del_init(&fi->inmem_ilist);
+			spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
+		}
+		mutex_unlock(&fi->inmem_lock);
+	}
+
+	clear_inode_flag(inode, FI_ATOMIC_FILE);
+	fi->i_gc_failures[GC_FAILURE_ATOMIC] = 0;
+	stat_dec_atomic_write(inode);
+}
+
+void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct list_head *head = &fi->inmem_pages;
+	struct inmem_pages *cur = NULL;
+	struct inmem_pages *tmp;
+
+	f2fs_bug_on(sbi, !IS_ATOMIC_WRITTEN_PAGE(page));
+
+	mutex_lock(&fi->inmem_lock);
+	list_for_each_entry(tmp, head, list) {
+		if (tmp->page == page) {
+			cur = tmp;
+			break;
+		}
+	}
+
+	f2fs_bug_on(sbi, !cur);
+	list_del(&cur->list);
+	mutex_unlock(&fi->inmem_lock);
+
+	dec_page_count(sbi, F2FS_INMEM_PAGES);
+	kmem_cache_free(inmem_entry_slab, cur);
+
+	ClearPageUptodate(page);
+	set_page_private(page, 0);
+	ClearPagePrivate(page);
+	f2fs_put_page(page, 0);
+
+	trace_f2fs_commit_inmem_page(page, INMEM_INVALIDATE);
+}
+
+static int __f2fs_commit_inmem_pages(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct inmem_pages *cur, *tmp;
+	struct f2fs_io_info fio = {
+		.sbi = sbi,
+		.ino = inode->i_ino,
+		.type = DATA,
+		.op = REQ_OP_WRITE,
+		.op_flags = REQ_SYNC | REQ_PRIO,
+		.io_type = FS_DATA_IO,
+	};
+	struct list_head revoke_list;
+	pgoff_t last_idx = ULONG_MAX;
+	int err = 0;
+
+	INIT_LIST_HEAD(&revoke_list);
+
+	list_for_each_entry_safe(cur, tmp, &fi->inmem_pages, list) {
+		struct page *page = cur->page;
+
+		lock_page(page);
+		if (page->mapping == inode->i_mapping) {
+			trace_f2fs_commit_inmem_page(page, INMEM);
+
+			set_page_dirty(page);
+			f2fs_wait_on_page_writeback(page, DATA, true);
+			if (clear_page_dirty_for_io(page)) {
+				inode_dec_dirty_pages(inode);
+				f2fs_remove_dirty_inode(inode);
+			}
+retry:
+			fio.page = page;
+			fio.old_blkaddr = NULL_ADDR;
+			fio.encrypted_page = NULL;
+			fio.need_lock = LOCK_DONE;
+			err = f2fs_do_write_data_page(&fio);
+			if (err) {
+				if (err == -ENOMEM) {
+					congestion_wait(BLK_RW_ASYNC, HZ/50);
+					cond_resched();
+					goto retry;
+				}
+				unlock_page(page);
+				break;
+			}
+			/* record old blkaddr for revoking */
+			cur->old_addr = fio.old_blkaddr;
+			last_idx = page->index;
+		}
+		unlock_page(page);
+		list_move_tail(&cur->list, &revoke_list);
+	}
+
+	if (last_idx != ULONG_MAX)
+		f2fs_submit_merged_write_cond(sbi, inode, 0, last_idx, DATA);
+
+	if (err) {
+		/*
+		 * try to revoke all committed pages, but still we could fail
+		 * due to no memory or other reason, if that happened, EAGAIN
+		 * will be returned, which means in such case, transaction is
+		 * already not integrity, caller should use journal to do the
+		 * recovery or rewrite & commit last transaction. For other
+		 * error number, revoking was done by filesystem itself.
+		 */
+		err = __revoke_inmem_pages(inode, &revoke_list,
+						false, true, false);
+
+		/* drop all uncommitted pages */
+		__revoke_inmem_pages(inode, &fi->inmem_pages,
+						true, false, false);
+	} else {
+		__revoke_inmem_pages(inode, &revoke_list,
+						false, false, false);
+	}
+
+	return err;
+}
+
+int f2fs_commit_inmem_pages(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	int err;
+
+	f2fs_balance_fs(sbi, true);
+
+	down_write(&fi->i_gc_rwsem[WRITE]);
+
+	f2fs_lock_op(sbi);
+	set_inode_flag(inode, FI_ATOMIC_COMMIT);
+
+	mutex_lock(&fi->inmem_lock);
+	err = __f2fs_commit_inmem_pages(inode);
+
+	spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
+	if (!list_empty(&fi->inmem_ilist))
+		list_del_init(&fi->inmem_ilist);
+	spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
+	mutex_unlock(&fi->inmem_lock);
+
+	clear_inode_flag(inode, FI_ATOMIC_COMMIT);
+
+	f2fs_unlock_op(sbi);
+	up_write(&fi->i_gc_rwsem[WRITE]);
+
+	return err;
+}
+
+/*
+ * This function balances dirty node and dentry pages.
+ * In addition, it controls garbage collection.
+ */
+void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
+{
+	if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
+		f2fs_show_injection_info(FAULT_CHECKPOINT);
+		f2fs_stop_checkpoint(sbi, false);
+	}
+
+	/* balance_fs_bg is able to be pending */
+	if (need && excess_cached_nats(sbi))
+		f2fs_balance_fs_bg(sbi);
+
+	/*
+	 * We should do GC or end up with checkpoint, if there are so many dirty
+	 * dir/node pages without enough free segments.
+	 */
+	if (has_not_enough_free_secs(sbi, 0, 0)) {
+		mutex_lock(&sbi->gc_mutex);
+		f2fs_gc(sbi, false, false, NULL_SEGNO);
+	}
+}
+
+void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
+{
+	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
+		return;
+
+	/* try to shrink extent cache when there is no enough memory */
+	if (!f2fs_available_free_memory(sbi, EXTENT_CACHE))
+		f2fs_shrink_extent_tree(sbi, EXTENT_CACHE_SHRINK_NUMBER);
+
+	/* check the # of cached NAT entries */
+	if (!f2fs_available_free_memory(sbi, NAT_ENTRIES))
+		f2fs_try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK);
+
+	if (!f2fs_available_free_memory(sbi, FREE_NIDS))
+		f2fs_try_to_free_nids(sbi, MAX_FREE_NIDS);
+	else
+		f2fs_build_free_nids(sbi, false, false);
+
+	if (!is_idle(sbi) &&
+		(!excess_dirty_nats(sbi) && !excess_dirty_nodes(sbi)))
+		return;
+
+	/* checkpoint is the only way to shrink partial cached entries */
+	if (!f2fs_available_free_memory(sbi, NAT_ENTRIES) ||
+			!f2fs_available_free_memory(sbi, INO_ENTRIES) ||
+			excess_prefree_segs(sbi) ||
+			excess_dirty_nats(sbi) ||
+			excess_dirty_nodes(sbi) ||
+			f2fs_time_over(sbi, CP_TIME)) {
+		if (test_opt(sbi, DATA_FLUSH)) {
+			struct blk_plug plug;
+
+			blk_start_plug(&plug);
+			f2fs_sync_dirty_inodes(sbi, FILE_INODE);
+			blk_finish_plug(&plug);
+		}
+		f2fs_sync_fs(sbi->sb, true);
+		stat_inc_bg_cp_count(sbi->stat_info);
+	}
+}
+
+static int __submit_flush_wait(struct f2fs_sb_info *sbi,
+				struct block_device *bdev)
+{
+	struct bio *bio = f2fs_bio_alloc(sbi, 0, true);
+	int ret;
+
+	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
+	bio_set_dev(bio, bdev);
+	ret = submit_bio_wait(bio);
+	bio_put(bio);
+
+	trace_f2fs_issue_flush(bdev, test_opt(sbi, NOBARRIER),
+				test_opt(sbi, FLUSH_MERGE), ret);
+	return ret;
+}
+
+static int submit_flush_wait(struct f2fs_sb_info *sbi, nid_t ino)
+{
+	int ret = 0;
+	int i;
+
+	if (!f2fs_is_multi_device(sbi))
+		return __submit_flush_wait(sbi, sbi->sb->s_bdev);
+
+	for (i = 0; i < sbi->s_ndevs; i++) {
+		if (!f2fs_is_dirty_device(sbi, ino, i, FLUSH_INO))
+			continue;
+		ret = __submit_flush_wait(sbi, FDEV(i).bdev);
+		if (ret)
+			break;
+	}
+	return ret;
+}
+
+static int issue_flush_thread(void *data)
+{
+	struct f2fs_sb_info *sbi = data;
+	struct flush_cmd_control *fcc = SM_I(sbi)->fcc_info;
+	wait_queue_head_t *q = &fcc->flush_wait_queue;
+repeat:
+	if (kthread_should_stop())
+		return 0;
+
+	sb_start_intwrite(sbi->sb);
+
+	if (!llist_empty(&fcc->issue_list)) {
+		struct flush_cmd *cmd, *next;
+		int ret;
+
+		fcc->dispatch_list = llist_del_all(&fcc->issue_list);
+		fcc->dispatch_list = llist_reverse_order(fcc->dispatch_list);
+
+		cmd = llist_entry(fcc->dispatch_list, struct flush_cmd, llnode);
+
+		ret = submit_flush_wait(sbi, cmd->ino);
+		atomic_inc(&fcc->issued_flush);
+
+		llist_for_each_entry_safe(cmd, next,
+					  fcc->dispatch_list, llnode) {
+			cmd->ret = ret;
+			complete(&cmd->wait);
+		}
+		fcc->dispatch_list = NULL;
+	}
+
+	sb_end_intwrite(sbi->sb);
+
+	wait_event_interruptible(*q,
+		kthread_should_stop() || !llist_empty(&fcc->issue_list));
+	goto repeat;
+}
+
+int f2fs_issue_flush(struct f2fs_sb_info *sbi, nid_t ino)
+{
+	struct flush_cmd_control *fcc = SM_I(sbi)->fcc_info;
+	struct flush_cmd cmd;
+	int ret;
+
+	if (test_opt(sbi, NOBARRIER))
+		return 0;
+
+	if (!test_opt(sbi, FLUSH_MERGE)) {
+		atomic_inc(&fcc->issing_flush);
+		ret = submit_flush_wait(sbi, ino);
+		atomic_dec(&fcc->issing_flush);
+		atomic_inc(&fcc->issued_flush);
+		return ret;
+	}
+
+	if (atomic_inc_return(&fcc->issing_flush) == 1 ||
+	    f2fs_is_multi_device(sbi)) {
+		ret = submit_flush_wait(sbi, ino);
+		atomic_dec(&fcc->issing_flush);
+
+		atomic_inc(&fcc->issued_flush);
+		return ret;
+	}
+
+	cmd.ino = ino;
+	init_completion(&cmd.wait);
+
+	llist_add(&cmd.llnode, &fcc->issue_list);
+
+	/* update issue_list before we wake up issue_flush thread */
+	smp_mb();
+
+	if (waitqueue_active(&fcc->flush_wait_queue))
+		wake_up(&fcc->flush_wait_queue);
+
+	if (fcc->f2fs_issue_flush) {
+		wait_for_completion(&cmd.wait);
+		atomic_dec(&fcc->issing_flush);
+	} else {
+		struct llist_node *list;
+
+		list = llist_del_all(&fcc->issue_list);
+		if (!list) {
+			wait_for_completion(&cmd.wait);
+			atomic_dec(&fcc->issing_flush);
+		} else {
+			struct flush_cmd *tmp, *next;
+
+			ret = submit_flush_wait(sbi, ino);
+
+			llist_for_each_entry_safe(tmp, next, list, llnode) {
+				if (tmp == &cmd) {
+					cmd.ret = ret;
+					atomic_dec(&fcc->issing_flush);
+					continue;
+				}
+				tmp->ret = ret;
+				complete(&tmp->wait);
+			}
+		}
+	}
+
+	return cmd.ret;
+}
+
+int f2fs_create_flush_cmd_control(struct f2fs_sb_info *sbi)
+{
+	dev_t dev = sbi->sb->s_bdev->bd_dev;
+	struct flush_cmd_control *fcc;
+	int err = 0;
+
+	if (SM_I(sbi)->fcc_info) {
+		fcc = SM_I(sbi)->fcc_info;
+		if (fcc->f2fs_issue_flush)
+			return err;
+		goto init_thread;
+	}
+
+	fcc = f2fs_kzalloc(sbi, sizeof(struct flush_cmd_control), GFP_KERNEL);
+	if (!fcc)
+		return -ENOMEM;
+	atomic_set(&fcc->issued_flush, 0);
+	atomic_set(&fcc->issing_flush, 0);
+	init_waitqueue_head(&fcc->flush_wait_queue);
+	init_llist_head(&fcc->issue_list);
+	SM_I(sbi)->fcc_info = fcc;
+	if (!test_opt(sbi, FLUSH_MERGE))
+		return err;
+
+init_thread:
+	fcc->f2fs_issue_flush = kthread_run(issue_flush_thread, sbi,
+				"f2fs_flush-%u:%u", MAJOR(dev), MINOR(dev));
+	if (IS_ERR(fcc->f2fs_issue_flush)) {
+		err = PTR_ERR(fcc->f2fs_issue_flush);
+		kfree(fcc);
+		SM_I(sbi)->fcc_info = NULL;
+		return err;
+	}
+
+	return err;
+}
+
+void f2fs_destroy_flush_cmd_control(struct f2fs_sb_info *sbi, bool free)
+{
+	struct flush_cmd_control *fcc = SM_I(sbi)->fcc_info;
+
+	if (fcc && fcc->f2fs_issue_flush) {
+		struct task_struct *flush_thread = fcc->f2fs_issue_flush;
+
+		fcc->f2fs_issue_flush = NULL;
+		kthread_stop(flush_thread);
+	}
+	if (free) {
+		kfree(fcc);
+		SM_I(sbi)->fcc_info = NULL;
+	}
+}
+
+int f2fs_flush_device_cache(struct f2fs_sb_info *sbi)
+{
+	int ret = 0, i;
+
+	if (!f2fs_is_multi_device(sbi))
+		return 0;
+
+	for (i = 1; i < sbi->s_ndevs; i++) {
+		if (!f2fs_test_bit(i, (char *)&sbi->dirty_device))
+			continue;
+		ret = __submit_flush_wait(sbi, FDEV(i).bdev);
+		if (ret)
+			break;
+
+		spin_lock(&sbi->dev_lock);
+		f2fs_clear_bit(i, (char *)&sbi->dirty_device);
+		spin_unlock(&sbi->dev_lock);
+	}
+
+	return ret;
+}
+
+static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
+		enum dirty_type dirty_type)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+
+	/* need not be added */
+	if (IS_CURSEG(sbi, segno))
+		return;
+
+	if (!test_and_set_bit(segno, dirty_i->dirty_segmap[dirty_type]))
+		dirty_i->nr_dirty[dirty_type]++;
+
+	if (dirty_type == DIRTY) {
+		struct seg_entry *sentry = get_seg_entry(sbi, segno);
+		enum dirty_type t = sentry->type;
+
+		if (unlikely(t >= DIRTY)) {
+			f2fs_bug_on(sbi, 1);
+			return;
+		}
+		if (!test_and_set_bit(segno, dirty_i->dirty_segmap[t]))
+			dirty_i->nr_dirty[t]++;
+	}
+}
+
+static void __remove_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
+		enum dirty_type dirty_type)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+
+	if (test_and_clear_bit(segno, dirty_i->dirty_segmap[dirty_type]))
+		dirty_i->nr_dirty[dirty_type]--;
+
+	if (dirty_type == DIRTY) {
+		struct seg_entry *sentry = get_seg_entry(sbi, segno);
+		enum dirty_type t = sentry->type;
+
+		if (test_and_clear_bit(segno, dirty_i->dirty_segmap[t]))
+			dirty_i->nr_dirty[t]--;
+
+		if (get_valid_blocks(sbi, segno, true) == 0)
+			clear_bit(GET_SEC_FROM_SEG(sbi, segno),
+						dirty_i->victim_secmap);
+	}
+}
+
+/*
+ * Should not occur error such as -ENOMEM.
+ * Adding dirty entry into seglist is not critical operation.
+ * If a given segment is one of current working segments, it won't be added.
+ */
+static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	unsigned short valid_blocks;
+
+	if (segno == NULL_SEGNO || IS_CURSEG(sbi, segno))
+		return;
+
+	mutex_lock(&dirty_i->seglist_lock);
+
+	valid_blocks = get_valid_blocks(sbi, segno, false);
+
+	if (valid_blocks == 0) {
+		__locate_dirty_segment(sbi, segno, PRE);
+		__remove_dirty_segment(sbi, segno, DIRTY);
+	} else if (valid_blocks < sbi->blocks_per_seg) {
+		__locate_dirty_segment(sbi, segno, DIRTY);
+	} else {
+		/* Recovery routine with SSR needs this */
+		__remove_dirty_segment(sbi, segno, DIRTY);
+	}
+
+	mutex_unlock(&dirty_i->seglist_lock);
+}
+
+static struct discard_cmd *__create_discard_cmd(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t lstart,
+		block_t start, block_t len)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *pend_list;
+	struct discard_cmd *dc;
+
+	f2fs_bug_on(sbi, !len);
+
+	pend_list = &dcc->pend_list[plist_idx(len)];
+
+	dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS);
+	INIT_LIST_HEAD(&dc->list);
+	dc->bdev = bdev;
+	dc->lstart = lstart;
+	dc->start = start;
+	dc->len = len;
+	dc->ref = 0;
+	dc->state = D_PREP;
+	dc->issuing = 0;
+	dc->error = 0;
+	init_completion(&dc->wait);
+	list_add_tail(&dc->list, pend_list);
+	spin_lock_init(&dc->lock);
+	dc->bio_ref = 0;
+	atomic_inc(&dcc->discard_cmd_cnt);
+	dcc->undiscard_blks += len;
+
+	return dc;
+}
+
+static struct discard_cmd *__attach_discard_cmd(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len,
+				struct rb_node *parent, struct rb_node **p)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *dc;
+
+	dc = __create_discard_cmd(sbi, bdev, lstart, start, len);
+
+	rb_link_node(&dc->rb_node, parent, p);
+	rb_insert_color(&dc->rb_node, &dcc->root);
+
+	return dc;
+}
+
+static void __detach_discard_cmd(struct discard_cmd_control *dcc,
+							struct discard_cmd *dc)
+{
+	if (dc->state == D_DONE)
+		atomic_sub(dc->issuing, &dcc->issing_discard);
+
+	list_del(&dc->list);
+	rb_erase(&dc->rb_node, &dcc->root);
+	dcc->undiscard_blks -= dc->len;
+
+	kmem_cache_free(discard_cmd_slab, dc);
+
+	atomic_dec(&dcc->discard_cmd_cnt);
+}
+
+static void __remove_discard_cmd(struct f2fs_sb_info *sbi,
+							struct discard_cmd *dc)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	unsigned long flags;
+
+	trace_f2fs_remove_discard(dc->bdev, dc->start, dc->len);
+
+	spin_lock_irqsave(&dc->lock, flags);
+	if (dc->bio_ref) {
+		spin_unlock_irqrestore(&dc->lock, flags);
+		return;
+	}
+	spin_unlock_irqrestore(&dc->lock, flags);
+
+	f2fs_bug_on(sbi, dc->ref);
+
+	if (dc->error == -EOPNOTSUPP)
+		dc->error = 0;
+
+	if (dc->error)
+		f2fs_msg(sbi->sb, KERN_INFO,
+			"Issue discard(%u, %u, %u) failed, ret: %d",
+			dc->lstart, dc->start, dc->len, dc->error);
+	__detach_discard_cmd(dcc, dc);
+}
+
+static void f2fs_submit_discard_endio(struct bio *bio)
+{
+	struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
+	unsigned long flags;
+
+	dc->error = blk_status_to_errno(bio->bi_status);
+
+	spin_lock_irqsave(&dc->lock, flags);
+	dc->bio_ref--;
+	if (!dc->bio_ref && dc->state == D_SUBMIT) {
+		dc->state = D_DONE;
+		complete_all(&dc->wait);
+	}
+	spin_unlock_irqrestore(&dc->lock, flags);
+	bio_put(bio);
+}
+
+static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
+				block_t start, block_t end)
+{
+#ifdef CONFIG_F2FS_CHECK_FS
+	struct seg_entry *sentry;
+	unsigned int segno;
+	block_t blk = start;
+	unsigned long offset, size, max_blocks = sbi->blocks_per_seg;
+	unsigned long *map;
+
+	while (blk < end) {
+		segno = GET_SEGNO(sbi, blk);
+		sentry = get_seg_entry(sbi, segno);
+		offset = GET_BLKOFF_FROM_SEG0(sbi, blk);
+
+		if (end < START_BLOCK(sbi, segno + 1))
+			size = GET_BLKOFF_FROM_SEG0(sbi, end);
+		else
+			size = max_blocks;
+		map = (unsigned long *)(sentry->cur_valid_map);
+		offset = __find_rev_next_bit(map, size, offset);
+		f2fs_bug_on(sbi, offset != size);
+		blk = START_BLOCK(sbi, segno + 1);
+	}
+#endif
+}
+
+static void __init_discard_policy(struct f2fs_sb_info *sbi,
+				struct discard_policy *dpolicy,
+				int discard_type, unsigned int granularity)
+{
+	/* common policy */
+	dpolicy->type = discard_type;
+	dpolicy->sync = true;
+	dpolicy->ordered = false;
+	dpolicy->granularity = granularity;
+
+	dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
+	dpolicy->io_aware_gran = MAX_PLIST_NUM;
+
+	if (discard_type == DPOLICY_BG) {
+		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
+		dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
+		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
+		dpolicy->io_aware = true;
+		dpolicy->sync = false;
+		dpolicy->ordered = true;
+		if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL) {
+			dpolicy->granularity = 1;
+			dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME;
+		}
+	} else if (discard_type == DPOLICY_FORCE) {
+		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
+		dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
+		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
+		dpolicy->io_aware = false;
+	} else if (discard_type == DPOLICY_FSTRIM) {
+		dpolicy->io_aware = false;
+	} else if (discard_type == DPOLICY_UMOUNT) {
+		dpolicy->max_requests = UINT_MAX;
+		dpolicy->io_aware = false;
+	}
+}
+
+static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len);
+/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
+static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
+						struct discard_policy *dpolicy,
+						struct discard_cmd *dc,
+						unsigned int *issued)
+{
+	struct block_device *bdev = dc->bdev;
+	struct request_queue *q = bdev_get_queue(bdev);
+	unsigned int max_discard_blocks =
+			SECTOR_TO_BLOCK(q->limits.max_discard_sectors);
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
+					&(dcc->fstrim_list) : &(dcc->wait_list);
+	int flag = dpolicy->sync ? REQ_SYNC : 0;
+	block_t lstart, start, len, total_len;
+	int err = 0;
+
+	if (dc->state != D_PREP)
+		return 0;
+
+	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
+		return 0;
+
+	trace_f2fs_issue_discard(bdev, dc->start, dc->len);
+
+	lstart = dc->lstart;
+	start = dc->start;
+	len = dc->len;
+	total_len = len;
+
+	dc->len = 0;
+
+	while (total_len && *issued < dpolicy->max_requests && !err) {
+		struct bio *bio = NULL;
+		unsigned long flags;
+		bool last = true;
+
+		if (len > max_discard_blocks) {
+			len = max_discard_blocks;
+			last = false;
+		}
+
+		(*issued)++;
+		if (*issued == dpolicy->max_requests)
+			last = true;
+
+		dc->len += len;
+
+		if (time_to_inject(sbi, FAULT_DISCARD)) {
+			f2fs_show_injection_info(FAULT_DISCARD);
+			err = -EIO;
+			goto submit;
+		}
+		err = __blkdev_issue_discard(bdev,
+					SECTOR_FROM_BLOCK(start),
+					SECTOR_FROM_BLOCK(len),
+					GFP_NOFS, 0, &bio);
+submit:
+		if (err) {
+			spin_lock_irqsave(&dc->lock, flags);
+			if (dc->state == D_PARTIAL)
+				dc->state = D_SUBMIT;
+			spin_unlock_irqrestore(&dc->lock, flags);
+
+			break;
+		}
+
+		f2fs_bug_on(sbi, !bio);
+
+		/*
+		 * should keep before submission to avoid D_DONE
+		 * right away
+		 */
+		spin_lock_irqsave(&dc->lock, flags);
+		if (last)
+			dc->state = D_SUBMIT;
+		else
+			dc->state = D_PARTIAL;
+		dc->bio_ref++;
+		spin_unlock_irqrestore(&dc->lock, flags);
+
+		atomic_inc(&dcc->issing_discard);
+		dc->issuing++;
+		list_move_tail(&dc->list, wait_list);
+
+		/* sanity check on discard range */
+		__check_sit_bitmap(sbi, lstart, lstart + len);
+
+		bio->bi_private = dc;
+		bio->bi_end_io = f2fs_submit_discard_endio;
+		bio->bi_opf |= flag;
+		submit_bio(bio);
+
+		atomic_inc(&dcc->issued_discard);
+
+		f2fs_update_iostat(sbi, FS_DISCARD, 1);
+
+		lstart += len;
+		start += len;
+		total_len -= len;
+		len = total_len;
+	}
+
+	if (!err && len)
+		__update_discard_tree_range(sbi, bdev, lstart, start, len);
+	return err;
+}
+
+static struct discard_cmd *__insert_discard_tree(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len,
+				struct rb_node **insert_p,
+				struct rb_node *insert_parent)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	struct discard_cmd *dc = NULL;
+
+	if (insert_p && insert_parent) {
+		parent = insert_parent;
+		p = insert_p;
+		goto do_insert;
+	}
+
+	p = f2fs_lookup_rb_tree_for_insert(sbi, &dcc->root, &parent, lstart);
+do_insert:
+	dc = __attach_discard_cmd(sbi, bdev, lstart, start, len, parent, p);
+	if (!dc)
+		return NULL;
+
+	return dc;
+}
+
+static void __relocate_discard_cmd(struct discard_cmd_control *dcc,
+						struct discard_cmd *dc)
+{
+	list_move_tail(&dc->list, &dcc->pend_list[plist_idx(dc->len)]);
+}
+
+static void __punch_discard_cmd(struct f2fs_sb_info *sbi,
+				struct discard_cmd *dc, block_t blkaddr)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_info di = dc->di;
+	bool modified = false;
+
+	if (dc->state == D_DONE || dc->len == 1) {
+		__remove_discard_cmd(sbi, dc);
+		return;
+	}
+
+	dcc->undiscard_blks -= di.len;
+
+	if (blkaddr > di.lstart) {
+		dc->len = blkaddr - dc->lstart;
+		dcc->undiscard_blks += dc->len;
+		__relocate_discard_cmd(dcc, dc);
+		modified = true;
+	}
+
+	if (blkaddr < di.lstart + di.len - 1) {
+		if (modified) {
+			__insert_discard_tree(sbi, dc->bdev, blkaddr + 1,
+					di.start + blkaddr + 1 - di.lstart,
+					di.lstart + di.len - 1 - blkaddr,
+					NULL, NULL);
+		} else {
+			dc->lstart++;
+			dc->len--;
+			dc->start++;
+			dcc->undiscard_blks += dc->len;
+			__relocate_discard_cmd(dcc, dc);
+		}
+	}
+}
+
+static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
+				struct block_device *bdev, block_t lstart,
+				block_t start, block_t len)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct discard_cmd *dc;
+	struct discard_info di = {0};
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	struct request_queue *q = bdev_get_queue(bdev);
+	unsigned int max_discard_blocks =
+			SECTOR_TO_BLOCK(q->limits.max_discard_sectors);
+	block_t end = lstart + len;
+
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
+					NULL, lstart,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true);
+	if (dc)
+		prev_dc = dc;
+
+	if (!prev_dc) {
+		di.lstart = lstart;
+		di.len = next_dc ? next_dc->lstart - lstart : len;
+		di.len = min(di.len, len);
+		di.start = start;
+	}
+
+	while (1) {
+		struct rb_node *node;
+		bool merged = false;
+		struct discard_cmd *tdc = NULL;
+
+		if (prev_dc) {
+			di.lstart = prev_dc->lstart + prev_dc->len;
+			if (di.lstart < lstart)
+				di.lstart = lstart;
+			if (di.lstart >= end)
+				break;
+
+			if (!next_dc || next_dc->lstart > end)
+				di.len = end - di.lstart;
+			else
+				di.len = next_dc->lstart - di.lstart;
+			di.start = start + di.lstart - lstart;
+		}
+
+		if (!di.len)
+			goto next;
+
+		if (prev_dc && prev_dc->state == D_PREP &&
+			prev_dc->bdev == bdev &&
+			__is_discard_back_mergeable(&di, &prev_dc->di,
+							max_discard_blocks)) {
+			prev_dc->di.len += di.len;
+			dcc->undiscard_blks += di.len;
+			__relocate_discard_cmd(dcc, prev_dc);
+			di = prev_dc->di;
+			tdc = prev_dc;
+			merged = true;
+		}
+
+		if (next_dc && next_dc->state == D_PREP &&
+			next_dc->bdev == bdev &&
+			__is_discard_front_mergeable(&di, &next_dc->di,
+							max_discard_blocks)) {
+			next_dc->di.lstart = di.lstart;
+			next_dc->di.len += di.len;
+			next_dc->di.start = di.start;
+			dcc->undiscard_blks += di.len;
+			__relocate_discard_cmd(dcc, next_dc);
+			if (tdc)
+				__remove_discard_cmd(sbi, tdc);
+			merged = true;
+		}
+
+		if (!merged) {
+			__insert_discard_tree(sbi, bdev, di.lstart, di.start,
+							di.len, NULL, NULL);
+		}
+ next:
+		prev_dc = next_dc;
+		if (!prev_dc)
+			break;
+
+		node = rb_next(&prev_dc->rb_node);
+		next_dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+	}
+}
+
+static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+	block_t lblkstart = blkstart;
+
+	trace_f2fs_queue_discard(bdev, blkstart, blklen);
+
+	if (f2fs_is_multi_device(sbi)) {
+		int devi = f2fs_target_device_index(sbi, blkstart);
+
+		blkstart -= FDEV(devi).start_blk;
+	}
+	mutex_lock(&SM_I(sbi)->dcc_info->cmd_lock);
+	__update_discard_tree_range(sbi, bdev, lblkstart, blkstart, blklen);
+	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
+	return 0;
+}
+
+static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	struct discard_cmd *dc;
+	struct blk_plug plug;
+	unsigned int pos = dcc->next_pos;
+	unsigned int issued = 0;
+	bool io_interrupted = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
+					NULL, pos,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true);
+	if (!dc)
+		dc = next_dc;
+
+	blk_start_plug(&plug);
+
+	while (dc) {
+		struct rb_node *node;
+		int err = 0;
+
+		if (dc->state != D_PREP)
+			goto next;
+
+		if (dpolicy->io_aware && !is_idle(sbi)) {
+			io_interrupted = true;
+			break;
+		}
+
+		dcc->next_pos = dc->lstart + dc->len;
+		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
+
+		if (issued >= dpolicy->max_requests)
+			break;
+next:
+		node = rb_next(&dc->rb_node);
+		if (err)
+			__remove_discard_cmd(sbi, dc);
+		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+	}
+
+	blk_finish_plug(&plug);
+
+	if (!dc)
+		dcc->next_pos = 0;
+
+	mutex_unlock(&dcc->cmd_lock);
+
+	if (!issued && io_interrupted)
+		issued = -1;
+
+	return issued;
+}
+
+static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *pend_list;
+	struct discard_cmd *dc, *tmp;
+	struct blk_plug plug;
+	int i, issued = 0;
+	bool io_interrupted = false;
+
+	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
+		if (i + 1 < dpolicy->granularity)
+			break;
+
+		if (i < DEFAULT_DISCARD_GRANULARITY && dpolicy->ordered)
+			return __issue_discard_cmd_orderly(sbi, dpolicy);
+
+		pend_list = &dcc->pend_list[i];
+
+		mutex_lock(&dcc->cmd_lock);
+		if (list_empty(pend_list))
+			goto next;
+		if (unlikely(dcc->rbtree_check))
+			f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
+								&dcc->root));
+		blk_start_plug(&plug);
+		list_for_each_entry_safe(dc, tmp, pend_list, list) {
+			f2fs_bug_on(sbi, dc->state != D_PREP);
+
+			if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
+								!is_idle(sbi)) {
+				io_interrupted = true;
+				break;
+			}
+
+			__submit_discard_cmd(sbi, dpolicy, dc, &issued);
+
+			if (issued >= dpolicy->max_requests)
+				break;
+		}
+		blk_finish_plug(&plug);
+next:
+		mutex_unlock(&dcc->cmd_lock);
+
+		if (issued >= dpolicy->max_requests || io_interrupted)
+			break;
+	}
+
+	if (!issued && io_interrupted)
+		issued = -1;
+
+	return issued;
+}
+
+static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *pend_list;
+	struct discard_cmd *dc, *tmp;
+	int i;
+	bool dropped = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
+		pend_list = &dcc->pend_list[i];
+		list_for_each_entry_safe(dc, tmp, pend_list, list) {
+			f2fs_bug_on(sbi, dc->state != D_PREP);
+			__remove_discard_cmd(sbi, dc);
+			dropped = true;
+		}
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	return dropped;
+}
+
+void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi)
+{
+	__drop_discard_cmd(sbi);
+}
+
+static unsigned int __wait_one_discard_bio(struct f2fs_sb_info *sbi,
+							struct discard_cmd *dc)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	unsigned int len = 0;
+
+	wait_for_completion_io(&dc->wait);
+	mutex_lock(&dcc->cmd_lock);
+	f2fs_bug_on(sbi, dc->state != D_DONE);
+	dc->ref--;
+	if (!dc->ref) {
+		if (!dc->error)
+			len = dc->len;
+		__remove_discard_cmd(sbi, dc);
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	return len;
+}
+
+static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi,
+						struct discard_policy *dpolicy,
+						block_t start, block_t end)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ?
+					&(dcc->fstrim_list) : &(dcc->wait_list);
+	struct discard_cmd *dc, *tmp;
+	bool need_wait;
+	unsigned int trimmed = 0;
+
+next:
+	need_wait = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	list_for_each_entry_safe(dc, tmp, wait_list, list) {
+		if (dc->lstart + dc->len <= start || end <= dc->lstart)
+			continue;
+		if (dc->len < dpolicy->granularity)
+			continue;
+		if (dc->state == D_DONE && !dc->ref) {
+			wait_for_completion_io(&dc->wait);
+			if (!dc->error)
+				trimmed += dc->len;
+			__remove_discard_cmd(sbi, dc);
+		} else {
+			dc->ref++;
+			need_wait = true;
+			break;
+		}
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	if (need_wait) {
+		trimmed += __wait_one_discard_bio(sbi, dc);
+		goto next;
+	}
+
+	return trimmed;
+}
+
+static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
+						struct discard_policy *dpolicy)
+{
+	struct discard_policy dp;
+	unsigned int discard_blks;
+
+	if (dpolicy)
+		return __wait_discard_cmd_range(sbi, dpolicy, 0, UINT_MAX);
+
+	/* wait all */
+	__init_discard_policy(sbi, &dp, DPOLICY_FSTRIM, 1);
+	discard_blks = __wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
+	__init_discard_policy(sbi, &dp, DPOLICY_UMOUNT, 1);
+	discard_blks += __wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
+
+	return discard_blks;
+}
+
+/* This should be covered by global mutex, &sit_i->sentry_lock */
+static void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *dc;
+	bool need_wait = false;
+
+	mutex_lock(&dcc->cmd_lock);
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree(&dcc->root,
+							NULL, blkaddr);
+	if (dc) {
+		if (dc->state == D_PREP) {
+			__punch_discard_cmd(sbi, dc, blkaddr);
+		} else {
+			dc->ref++;
+			need_wait = true;
+		}
+	}
+	mutex_unlock(&dcc->cmd_lock);
+
+	if (need_wait)
+		__wait_one_discard_bio(sbi, dc);
+}
+
+void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+	if (dcc && dcc->f2fs_issue_discard) {
+		struct task_struct *discard_thread = dcc->f2fs_issue_discard;
+
+		dcc->f2fs_issue_discard = NULL;
+		kthread_stop(discard_thread);
+	}
+}
+
+/* This comes from f2fs_put_super */
+bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_policy dpolicy;
+	bool dropped;
+
+	__init_discard_policy(sbi, &dpolicy, DPOLICY_UMOUNT,
+					dcc->discard_granularity);
+	__issue_discard_cmd(sbi, &dpolicy);
+	dropped = __drop_discard_cmd(sbi);
+
+	/* just to make sure there is no pending discard commands */
+	__wait_all_discard_cmd(sbi, NULL);
+
+	f2fs_bug_on(sbi, atomic_read(&dcc->discard_cmd_cnt));
+	return dropped;
+}
+
+static int issue_discard_thread(void *data)
+{
+	struct f2fs_sb_info *sbi = data;
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	wait_queue_head_t *q = &dcc->discard_wait_queue;
+	struct discard_policy dpolicy;
+	unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
+	int issued;
+
+	set_freezable();
+
+	do {
+		__init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
+					dcc->discard_granularity);
+
+		wait_event_interruptible_timeout(*q,
+				kthread_should_stop() || freezing(current) ||
+				dcc->discard_wake,
+				msecs_to_jiffies(wait_ms));
+
+		if (dcc->discard_wake)
+			dcc->discard_wake = 0;
+
+		if (try_to_freeze())
+			continue;
+		if (f2fs_readonly(sbi->sb))
+			continue;
+		if (kthread_should_stop())
+			return 0;
+		if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+			wait_ms = dpolicy.max_interval;
+			continue;
+		}
+
+		if (sbi->gc_mode == GC_URGENT)
+			__init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
+
+		sb_start_intwrite(sbi->sb);
+
+		issued = __issue_discard_cmd(sbi, &dpolicy);
+		if (issued > 0) {
+			__wait_all_discard_cmd(sbi, &dpolicy);
+			wait_ms = dpolicy.min_interval;
+		} else if (issued == -1){
+			wait_ms = dpolicy.mid_interval;
+		} else {
+			wait_ms = dpolicy.max_interval;
+		}
+
+		sb_end_intwrite(sbi->sb);
+
+	} while (!kthread_should_stop());
+	return 0;
+}
+
+#ifdef CONFIG_BLK_DEV_ZONED
+static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+	sector_t sector, nr_sects;
+	block_t lblkstart = blkstart;
+	int devi = 0;
+
+	if (f2fs_is_multi_device(sbi)) {
+		devi = f2fs_target_device_index(sbi, blkstart);
+		blkstart -= FDEV(devi).start_blk;
+	}
+
+	/*
+	 * We need to know the type of the zone: for conventional zones,
+	 * use regular discard if the drive supports it. For sequential
+	 * zones, reset the zone write pointer.
+	 */
+	switch (get_blkz_type(sbi, bdev, blkstart)) {
+
+	case BLK_ZONE_TYPE_CONVENTIONAL:
+		if (!blk_queue_discard(bdev_get_queue(bdev)))
+			return 0;
+		return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
+	case BLK_ZONE_TYPE_SEQWRITE_REQ:
+	case BLK_ZONE_TYPE_SEQWRITE_PREF:
+		sector = SECTOR_FROM_BLOCK(blkstart);
+		nr_sects = SECTOR_FROM_BLOCK(blklen);
+
+		if (sector & (bdev_zone_sectors(bdev) - 1) ||
+				nr_sects != bdev_zone_sectors(bdev)) {
+			f2fs_msg(sbi->sb, KERN_INFO,
+				"(%d) %s: Unaligned discard attempted (block %x + %x)",
+				devi, sbi->s_ndevs ? FDEV(devi).path: "",
+				blkstart, blklen);
+			return -EIO;
+		}
+		trace_f2fs_issue_reset_zone(bdev, blkstart);
+		return blkdev_reset_zones(bdev, sector,
+					  nr_sects, GFP_NOFS);
+	default:
+		/* Unknown zone type: broken device ? */
+		return -EIO;
+	}
+}
+#endif
+
+static int __issue_discard_async(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t blklen)
+{
+#ifdef CONFIG_BLK_DEV_ZONED
+	if (f2fs_sb_has_blkzoned(sbi->sb) &&
+				bdev_zoned_model(bdev) != BLK_ZONED_NONE)
+		return __f2fs_issue_discard_zone(sbi, bdev, blkstart, blklen);
+#endif
+	return __queue_discard_cmd(sbi, bdev, blkstart, blklen);
+}
+
+static int f2fs_issue_discard(struct f2fs_sb_info *sbi,
+				block_t blkstart, block_t blklen)
+{
+	sector_t start = blkstart, len = 0;
+	struct block_device *bdev;
+	struct seg_entry *se;
+	unsigned int offset;
+	block_t i;
+	int err = 0;
+
+	bdev = f2fs_target_device(sbi, blkstart, NULL);
+
+	for (i = blkstart; i < blkstart + blklen; i++, len++) {
+		if (i != start) {
+			struct block_device *bdev2 =
+				f2fs_target_device(sbi, i, NULL);
+
+			if (bdev2 != bdev) {
+				err = __issue_discard_async(sbi, bdev,
+						start, len);
+				if (err)
+					return err;
+				bdev = bdev2;
+				start = i;
+				len = 0;
+			}
+		}
+
+		se = get_seg_entry(sbi, GET_SEGNO(sbi, i));
+		offset = GET_BLKOFF_FROM_SEG0(sbi, i);
+
+		if (!f2fs_test_and_set_bit(offset, se->discard_map))
+			sbi->discard_blks--;
+	}
+
+	if (len)
+		err = __issue_discard_async(sbi, bdev, start, len);
+	return err;
+}
+
+static bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
+							bool check_only)
+{
+	int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
+	int max_blocks = sbi->blocks_per_seg;
+	struct seg_entry *se = get_seg_entry(sbi, cpc->trim_start);
+	unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
+	unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
+	unsigned long *discard_map = (unsigned long *)se->discard_map;
+	unsigned long *dmap = SIT_I(sbi)->tmp_map;
+	unsigned int start = 0, end = -1;
+	bool force = (cpc->reason & CP_DISCARD);
+	struct discard_entry *de = NULL;
+	struct list_head *head = &SM_I(sbi)->dcc_info->entry_list;
+	int i;
+
+	if (se->valid_blocks == max_blocks || !f2fs_hw_support_discard(sbi))
+		return false;
+
+	if (!force) {
+		if (!f2fs_realtime_discard_enable(sbi) || !se->valid_blocks ||
+			SM_I(sbi)->dcc_info->nr_discards >=
+				SM_I(sbi)->dcc_info->max_discards)
+			return false;
+	}
+
+	/* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
+	for (i = 0; i < entries; i++)
+		dmap[i] = force ? ~ckpt_map[i] & ~discard_map[i] :
+				(cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
+
+	while (force || SM_I(sbi)->dcc_info->nr_discards <=
+				SM_I(sbi)->dcc_info->max_discards) {
+		start = __find_rev_next_bit(dmap, max_blocks, end + 1);
+		if (start >= max_blocks)
+			break;
+
+		end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1);
+		if (force && start && end != max_blocks
+					&& (end - start) < cpc->trim_minlen)
+			continue;
+
+		if (check_only)
+			return true;
+
+		if (!de) {
+			de = f2fs_kmem_cache_alloc(discard_entry_slab,
+								GFP_F2FS_ZERO);
+			de->start_blkaddr = START_BLOCK(sbi, cpc->trim_start);
+			list_add_tail(&de->list, head);
+		}
+
+		for (i = start; i < end; i++)
+			__set_bit_le(i, (void *)de->discard_map);
+
+		SM_I(sbi)->dcc_info->nr_discards += end - start;
+	}
+	return false;
+}
+
+static void release_discard_addr(struct discard_entry *entry)
+{
+	list_del(&entry->list);
+	kmem_cache_free(discard_entry_slab, entry);
+}
+
+void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi)
+{
+	struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
+	struct discard_entry *entry, *this;
+
+	/* drop caches */
+	list_for_each_entry_safe(entry, this, head, list)
+		release_discard_addr(entry);
+}
+
+/*
+ * Should call f2fs_clear_prefree_segments after checkpoint is done.
+ */
+static void set_prefree_as_free_segments(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	unsigned int segno;
+
+	mutex_lock(&dirty_i->seglist_lock);
+	for_each_set_bit(segno, dirty_i->dirty_segmap[PRE], MAIN_SEGS(sbi))
+		__set_test_and_free(sbi, segno);
+	mutex_unlock(&dirty_i->seglist_lock);
+}
+
+void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
+						struct cp_control *cpc)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *head = &dcc->entry_list;
+	struct discard_entry *entry, *this;
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	unsigned long *prefree_map = dirty_i->dirty_segmap[PRE];
+	unsigned int start = 0, end = -1;
+	unsigned int secno, start_segno;
+	bool force = (cpc->reason & CP_DISCARD);
+	bool need_align = test_opt(sbi, LFS) && sbi->segs_per_sec > 1;
+
+	mutex_lock(&dirty_i->seglist_lock);
+
+	while (1) {
+		int i;
+
+		if (need_align && end != -1)
+			end--;
+		start = find_next_bit(prefree_map, MAIN_SEGS(sbi), end + 1);
+		if (start >= MAIN_SEGS(sbi))
+			break;
+		end = find_next_zero_bit(prefree_map, MAIN_SEGS(sbi),
+								start + 1);
+
+		if (need_align) {
+			start = rounddown(start, sbi->segs_per_sec);
+			end = roundup(end, sbi->segs_per_sec);
+		}
+
+		for (i = start; i < end; i++) {
+			if (test_and_clear_bit(i, prefree_map))
+				dirty_i->nr_dirty[PRE]--;
+		}
+
+		if (!f2fs_realtime_discard_enable(sbi))
+			continue;
+
+		if (force && start >= cpc->trim_start &&
+					(end - 1) <= cpc->trim_end)
+				continue;
+
+		if (!test_opt(sbi, LFS) || sbi->segs_per_sec == 1) {
+			f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
+				(end - start) << sbi->log_blocks_per_seg);
+			continue;
+		}
+next:
+		secno = GET_SEC_FROM_SEG(sbi, start);
+		start_segno = GET_SEG_FROM_SEC(sbi, secno);
+		if (!IS_CURSEC(sbi, secno) &&
+			!get_valid_blocks(sbi, start, true))
+			f2fs_issue_discard(sbi, START_BLOCK(sbi, start_segno),
+				sbi->segs_per_sec << sbi->log_blocks_per_seg);
+
+		start = start_segno + sbi->segs_per_sec;
+		if (start < end)
+			goto next;
+		else
+			end = start - 1;
+	}
+	mutex_unlock(&dirty_i->seglist_lock);
+
+	/* send small discards */
+	list_for_each_entry_safe(entry, this, head, list) {
+		unsigned int cur_pos = 0, next_pos, len, total_len = 0;
+		bool is_valid = test_bit_le(0, entry->discard_map);
+
+find_next:
+		if (is_valid) {
+			next_pos = find_next_zero_bit_le(entry->discard_map,
+					sbi->blocks_per_seg, cur_pos);
+			len = next_pos - cur_pos;
+
+			if (f2fs_sb_has_blkzoned(sbi->sb) ||
+			    (force && len < cpc->trim_minlen))
+				goto skip;
+
+			f2fs_issue_discard(sbi, entry->start_blkaddr + cur_pos,
+									len);
+			total_len += len;
+		} else {
+			next_pos = find_next_bit_le(entry->discard_map,
+					sbi->blocks_per_seg, cur_pos);
+		}
+skip:
+		cur_pos = next_pos;
+		is_valid = !is_valid;
+
+		if (cur_pos < sbi->blocks_per_seg)
+			goto find_next;
+
+		release_discard_addr(entry);
+		dcc->nr_discards -= total_len;
+	}
+
+	wake_up_discard_thread(sbi, false);
+}
+
+static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
+{
+	dev_t dev = sbi->sb->s_bdev->bd_dev;
+	struct discard_cmd_control *dcc;
+	int err = 0, i;
+
+	if (SM_I(sbi)->dcc_info) {
+		dcc = SM_I(sbi)->dcc_info;
+		goto init_thread;
+	}
+
+	dcc = f2fs_kzalloc(sbi, sizeof(struct discard_cmd_control), GFP_KERNEL);
+	if (!dcc)
+		return -ENOMEM;
+
+	dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
+	INIT_LIST_HEAD(&dcc->entry_list);
+	for (i = 0; i < MAX_PLIST_NUM; i++)
+		INIT_LIST_HEAD(&dcc->pend_list[i]);
+	INIT_LIST_HEAD(&dcc->wait_list);
+	INIT_LIST_HEAD(&dcc->fstrim_list);
+	mutex_init(&dcc->cmd_lock);
+	atomic_set(&dcc->issued_discard, 0);
+	atomic_set(&dcc->issing_discard, 0);
+	atomic_set(&dcc->discard_cmd_cnt, 0);
+	dcc->nr_discards = 0;
+	dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
+	dcc->undiscard_blks = 0;
+	dcc->next_pos = 0;
+	dcc->root = RB_ROOT;
+	dcc->rbtree_check = false;
+
+	init_waitqueue_head(&dcc->discard_wait_queue);
+	SM_I(sbi)->dcc_info = dcc;
+init_thread:
+	dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
+				"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
+	if (IS_ERR(dcc->f2fs_issue_discard)) {
+		err = PTR_ERR(dcc->f2fs_issue_discard);
+		kfree(dcc);
+		SM_I(sbi)->dcc_info = NULL;
+		return err;
+	}
+
+	return err;
+}
+
+static void destroy_discard_cmd_control(struct f2fs_sb_info *sbi)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+
+	if (!dcc)
+		return;
+
+	f2fs_stop_discard_thread(sbi);
+
+	kfree(dcc);
+	SM_I(sbi)->dcc_info = NULL;
+}
+
+static bool __mark_sit_entry_dirty(struct f2fs_sb_info *sbi, unsigned int segno)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+
+	if (!__test_and_set_bit(segno, sit_i->dirty_sentries_bitmap)) {
+		sit_i->dirty_sentries++;
+		return false;
+	}
+
+	return true;
+}
+
+static void __set_sit_entry_type(struct f2fs_sb_info *sbi, int type,
+					unsigned int segno, int modified)
+{
+	struct seg_entry *se = get_seg_entry(sbi, segno);
+	se->type = type;
+	if (modified)
+		__mark_sit_entry_dirty(sbi, segno);
+}
+
+static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
+{
+	struct seg_entry *se;
+	unsigned int segno, offset;
+	long int new_vblocks;
+	bool exist;
+#ifdef CONFIG_F2FS_CHECK_FS
+	bool mir_exist;
+#endif
+
+	segno = GET_SEGNO(sbi, blkaddr);
+
+	se = get_seg_entry(sbi, segno);
+	new_vblocks = se->valid_blocks + del;
+	offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
+
+	f2fs_bug_on(sbi, (new_vblocks >> (sizeof(unsigned short) << 3) ||
+				(new_vblocks > sbi->blocks_per_seg)));
+
+	se->valid_blocks = new_vblocks;
+	se->mtime = get_mtime(sbi, false);
+	if (se->mtime > SIT_I(sbi)->max_mtime)
+		SIT_I(sbi)->max_mtime = se->mtime;
+
+	/* Update valid block bitmap */
+	if (del > 0) {
+		exist = f2fs_test_and_set_bit(offset, se->cur_valid_map);
+#ifdef CONFIG_F2FS_CHECK_FS
+		mir_exist = f2fs_test_and_set_bit(offset,
+						se->cur_valid_map_mir);
+		if (unlikely(exist != mir_exist)) {
+			f2fs_msg(sbi->sb, KERN_ERR, "Inconsistent error "
+				"when setting bitmap, blk:%u, old bit:%d",
+				blkaddr, exist);
+			f2fs_bug_on(sbi, 1);
+		}
+#endif
+		if (unlikely(exist)) {
+			f2fs_msg(sbi->sb, KERN_ERR,
+				"Bitmap was wrongly set, blk:%u", blkaddr);
+			f2fs_bug_on(sbi, 1);
+			se->valid_blocks--;
+			del = 0;
+		}
+
+		if (!f2fs_test_and_set_bit(offset, se->discard_map))
+			sbi->discard_blks--;
+
+		/* don't overwrite by SSR to keep node chain */
+		if (IS_NODESEG(se->type)) {
+			if (!f2fs_test_and_set_bit(offset, se->ckpt_valid_map))
+				se->ckpt_valid_blocks++;
+		}
+	} else {
+		exist = f2fs_test_and_clear_bit(offset, se->cur_valid_map);
+#ifdef CONFIG_F2FS_CHECK_FS
+		mir_exist = f2fs_test_and_clear_bit(offset,
+						se->cur_valid_map_mir);
+		if (unlikely(exist != mir_exist)) {
+			f2fs_msg(sbi->sb, KERN_ERR, "Inconsistent error "
+				"when clearing bitmap, blk:%u, old bit:%d",
+				blkaddr, exist);
+			f2fs_bug_on(sbi, 1);
+		}
+#endif
+		if (unlikely(!exist)) {
+			f2fs_msg(sbi->sb, KERN_ERR,
+				"Bitmap was wrongly cleared, blk:%u", blkaddr);
+			f2fs_bug_on(sbi, 1);
+			se->valid_blocks++;
+			del = 0;
+		}
+
+		if (f2fs_test_and_clear_bit(offset, se->discard_map))
+			sbi->discard_blks++;
+	}
+	if (!f2fs_test_bit(offset, se->ckpt_valid_map))
+		se->ckpt_valid_blocks += del;
+
+	__mark_sit_entry_dirty(sbi, segno);
+
+	/* update total number of valid blocks to be written in ckpt area */
+	SIT_I(sbi)->written_valid_blocks += del;
+
+	if (sbi->segs_per_sec > 1)
+		get_sec_entry(sbi, segno)->valid_blocks += del;
+}
+
+void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr)
+{
+	unsigned int segno = GET_SEGNO(sbi, addr);
+	struct sit_info *sit_i = SIT_I(sbi);
+
+	f2fs_bug_on(sbi, addr == NULL_ADDR);
+	if (addr == NEW_ADDR)
+		return;
+
+	invalidate_mapping_pages(META_MAPPING(sbi), addr, addr);
+
+	/* add it into sit main buffer */
+	down_write(&sit_i->sentry_lock);
+
+	update_sit_entry(sbi, addr, -1);
+
+	/* add it into dirty seglist */
+	locate_dirty_segment(sbi, segno);
+
+	up_write(&sit_i->sentry_lock);
+}
+
+bool f2fs_is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int segno, offset;
+	struct seg_entry *se;
+	bool is_cp = false;
+
+	if (!is_valid_data_blkaddr(sbi, blkaddr))
+		return true;
+
+	down_read(&sit_i->sentry_lock);
+
+	segno = GET_SEGNO(sbi, blkaddr);
+	se = get_seg_entry(sbi, segno);
+	offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
+
+	if (f2fs_test_bit(offset, se->ckpt_valid_map))
+		is_cp = true;
+
+	up_read(&sit_i->sentry_lock);
+
+	return is_cp;
+}
+
+/*
+ * This function should be resided under the curseg_mutex lock
+ */
+static void __add_sum_entry(struct f2fs_sb_info *sbi, int type,
+					struct f2fs_summary *sum)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	void *addr = curseg->sum_blk;
+	addr += curseg->next_blkoff * sizeof(struct f2fs_summary);
+	memcpy(addr, sum, sizeof(struct f2fs_summary));
+}
+
+/*
+ * Calculate the number of current summary pages for writing
+ */
+int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra)
+{
+	int valid_sum_count = 0;
+	int i, sum_in_page;
+
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
+		if (sbi->ckpt->alloc_type[i] == SSR)
+			valid_sum_count += sbi->blocks_per_seg;
+		else {
+			if (for_ra)
+				valid_sum_count += le16_to_cpu(
+					F2FS_CKPT(sbi)->cur_data_blkoff[i]);
+			else
+				valid_sum_count += curseg_blkoff(sbi, i);
+		}
+	}
+
+	sum_in_page = (PAGE_SIZE - 2 * SUM_JOURNAL_SIZE -
+			SUM_FOOTER_SIZE) / SUMMARY_SIZE;
+	if (valid_sum_count <= sum_in_page)
+		return 1;
+	else if ((valid_sum_count - sum_in_page) <=
+		(PAGE_SIZE - SUM_FOOTER_SIZE) / SUMMARY_SIZE)
+		return 2;
+	return 3;
+}
+
+/*
+ * Caller should put this summary page
+ */
+struct page *f2fs_get_sum_page(struct f2fs_sb_info *sbi, unsigned int segno)
+{
+	return f2fs_get_meta_page_nofail(sbi, GET_SUM_BLOCK(sbi, segno));
+}
+
+void f2fs_update_meta_page(struct f2fs_sb_info *sbi,
+					void *src, block_t blk_addr)
+{
+	struct page *page = f2fs_grab_meta_page(sbi, blk_addr);
+
+	memcpy(page_address(page), src, PAGE_SIZE);
+	set_page_dirty(page);
+	f2fs_put_page(page, 1);
+}
+
+static void write_sum_page(struct f2fs_sb_info *sbi,
+			struct f2fs_summary_block *sum_blk, block_t blk_addr)
+{
+	f2fs_update_meta_page(sbi, (void *)sum_blk, blk_addr);
+}
+
+static void write_current_sum_page(struct f2fs_sb_info *sbi,
+						int type, block_t blk_addr)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	struct page *page = f2fs_grab_meta_page(sbi, blk_addr);
+	struct f2fs_summary_block *src = curseg->sum_blk;
+	struct f2fs_summary_block *dst;
+
+	dst = (struct f2fs_summary_block *)page_address(page);
+	memset(dst, 0, PAGE_SIZE);
+
+	mutex_lock(&curseg->curseg_mutex);
+
+	down_read(&curseg->journal_rwsem);
+	memcpy(&dst->journal, curseg->journal, SUM_JOURNAL_SIZE);
+	up_read(&curseg->journal_rwsem);
+
+	memcpy(dst->entries, src->entries, SUM_ENTRY_SIZE);
+	memcpy(&dst->footer, &src->footer, SUM_FOOTER_SIZE);
+
+	mutex_unlock(&curseg->curseg_mutex);
+
+	set_page_dirty(page);
+	f2fs_put_page(page, 1);
+}
+
+static int is_next_segment_free(struct f2fs_sb_info *sbi, int type)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	unsigned int segno = curseg->segno + 1;
+	struct free_segmap_info *free_i = FREE_I(sbi);
+
+	if (segno < MAIN_SEGS(sbi) && segno % sbi->segs_per_sec)
+		return !test_bit(segno, free_i->free_segmap);
+	return 0;
+}
+
+/*
+ * Find a new segment from the free segments bitmap to right order
+ * This function should be returned with success, otherwise BUG
+ */
+static void get_new_segment(struct f2fs_sb_info *sbi,
+			unsigned int *newseg, bool new_sec, int dir)
+{
+	struct free_segmap_info *free_i = FREE_I(sbi);
+	unsigned int segno, secno, zoneno;
+	unsigned int total_zones = MAIN_SECS(sbi) / sbi->secs_per_zone;
+	unsigned int hint = GET_SEC_FROM_SEG(sbi, *newseg);
+	unsigned int old_zoneno = GET_ZONE_FROM_SEG(sbi, *newseg);
+	unsigned int left_start = hint;
+	bool init = true;
+	int go_left = 0;
+	int i;
+
+	spin_lock(&free_i->segmap_lock);
+
+	if (!new_sec && ((*newseg + 1) % sbi->segs_per_sec)) {
+		segno = find_next_zero_bit(free_i->free_segmap,
+			GET_SEG_FROM_SEC(sbi, hint + 1), *newseg + 1);
+		if (segno < GET_SEG_FROM_SEC(sbi, hint + 1))
+			goto got_it;
+	}
+find_other_zone:
+	secno = find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi), hint);
+	if (secno >= MAIN_SECS(sbi)) {
+		if (dir == ALLOC_RIGHT) {
+			secno = find_next_zero_bit(free_i->free_secmap,
+							MAIN_SECS(sbi), 0);
+			f2fs_bug_on(sbi, secno >= MAIN_SECS(sbi));
+		} else {
+			go_left = 1;
+			left_start = hint - 1;
+		}
+	}
+	if (go_left == 0)
+		goto skip_left;
+
+	while (test_bit(left_start, free_i->free_secmap)) {
+		if (left_start > 0) {
+			left_start--;
+			continue;
+		}
+		left_start = find_next_zero_bit(free_i->free_secmap,
+							MAIN_SECS(sbi), 0);
+		f2fs_bug_on(sbi, left_start >= MAIN_SECS(sbi));
+		break;
+	}
+	secno = left_start;
+skip_left:
+	segno = GET_SEG_FROM_SEC(sbi, secno);
+	zoneno = GET_ZONE_FROM_SEC(sbi, secno);
+
+	/* give up on finding another zone */
+	if (!init)
+		goto got_it;
+	if (sbi->secs_per_zone == 1)
+		goto got_it;
+	if (zoneno == old_zoneno)
+		goto got_it;
+	if (dir == ALLOC_LEFT) {
+		if (!go_left && zoneno + 1 >= total_zones)
+			goto got_it;
+		if (go_left && zoneno == 0)
+			goto got_it;
+	}
+	for (i = 0; i < NR_CURSEG_TYPE; i++)
+		if (CURSEG_I(sbi, i)->zone == zoneno)
+			break;
+
+	if (i < NR_CURSEG_TYPE) {
+		/* zone is in user, try another */
+		if (go_left)
+			hint = zoneno * sbi->secs_per_zone - 1;
+		else if (zoneno + 1 >= total_zones)
+			hint = 0;
+		else
+			hint = (zoneno + 1) * sbi->secs_per_zone;
+		init = false;
+		goto find_other_zone;
+	}
+got_it:
+	/* set it as dirty segment in free segmap */
+	f2fs_bug_on(sbi, test_bit(segno, free_i->free_segmap));
+	__set_inuse(sbi, segno);
+	*newseg = segno;
+	spin_unlock(&free_i->segmap_lock);
+}
+
+static void reset_curseg(struct f2fs_sb_info *sbi, int type, int modified)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	struct summary_footer *sum_footer;
+
+	curseg->segno = curseg->next_segno;
+	curseg->zone = GET_ZONE_FROM_SEG(sbi, curseg->segno);
+	curseg->next_blkoff = 0;
+	curseg->next_segno = NULL_SEGNO;
+
+	sum_footer = &(curseg->sum_blk->footer);
+	memset(sum_footer, 0, sizeof(struct summary_footer));
+	if (IS_DATASEG(type))
+		SET_SUM_TYPE(sum_footer, SUM_TYPE_DATA);
+	if (IS_NODESEG(type))
+		SET_SUM_TYPE(sum_footer, SUM_TYPE_NODE);
+	__set_sit_entry_type(sbi, type, curseg->segno, modified);
+}
+
+static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
+{
+	/* if segs_per_sec is large than 1, we need to keep original policy. */
+	if (sbi->segs_per_sec != 1)
+		return CURSEG_I(sbi, type)->segno;
+
+	if (test_opt(sbi, NOHEAP) &&
+		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
+		return 0;
+
+	if (SIT_I(sbi)->last_victim[ALLOC_NEXT])
+		return SIT_I(sbi)->last_victim[ALLOC_NEXT];
+
+	/* find segments from 0 to reuse freed segments */
+	if (F2FS_OPTION(sbi).alloc_mode == ALLOC_MODE_REUSE)
+		return 0;
+
+	return CURSEG_I(sbi, type)->segno;
+}
+
+/*
+ * Allocate a current working segment.
+ * This function always allocates a free segment in LFS manner.
+ */
+static void new_curseg(struct f2fs_sb_info *sbi, int type, bool new_sec)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	unsigned int segno = curseg->segno;
+	int dir = ALLOC_LEFT;
+
+	write_sum_page(sbi, curseg->sum_blk,
+				GET_SUM_BLOCK(sbi, segno));
+	if (type == CURSEG_WARM_DATA || type == CURSEG_COLD_DATA)
+		dir = ALLOC_RIGHT;
+
+	if (test_opt(sbi, NOHEAP))
+		dir = ALLOC_RIGHT;
+
+	segno = __get_next_segno(sbi, type);
+	get_new_segment(sbi, &segno, new_sec, dir);
+	curseg->next_segno = segno;
+	reset_curseg(sbi, type, 1);
+	curseg->alloc_type = LFS;
+}
+
+static void __next_free_blkoff(struct f2fs_sb_info *sbi,
+			struct curseg_info *seg, block_t start)
+{
+	struct seg_entry *se = get_seg_entry(sbi, seg->segno);
+	int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
+	unsigned long *target_map = SIT_I(sbi)->tmp_map;
+	unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
+	unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
+	int i, pos;
+
+	for (i = 0; i < entries; i++)
+		target_map[i] = ckpt_map[i] | cur_map[i];
+
+	pos = __find_rev_next_zero_bit(target_map, sbi->blocks_per_seg, start);
+
+	seg->next_blkoff = pos;
+}
+
+/*
+ * If a segment is written by LFS manner, next block offset is just obtained
+ * by increasing the current block offset. However, if a segment is written by
+ * SSR manner, next block offset obtained by calling __next_free_blkoff
+ */
+static void __refresh_next_blkoff(struct f2fs_sb_info *sbi,
+				struct curseg_info *seg)
+{
+	if (seg->alloc_type == SSR)
+		__next_free_blkoff(sbi, seg, seg->next_blkoff + 1);
+	else
+		seg->next_blkoff++;
+}
+
+/*
+ * This function always allocates a used segment(from dirty seglist) by SSR
+ * manner, so it should recover the existing segment information of valid blocks
+ */
+static void change_curseg(struct f2fs_sb_info *sbi, int type)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	unsigned int new_segno = curseg->next_segno;
+	struct f2fs_summary_block *sum_node;
+	struct page *sum_page;
+
+	write_sum_page(sbi, curseg->sum_blk,
+				GET_SUM_BLOCK(sbi, curseg->segno));
+	__set_test_and_inuse(sbi, new_segno);
+
+	mutex_lock(&dirty_i->seglist_lock);
+	__remove_dirty_segment(sbi, new_segno, PRE);
+	__remove_dirty_segment(sbi, new_segno, DIRTY);
+	mutex_unlock(&dirty_i->seglist_lock);
+
+	reset_curseg(sbi, type, 1);
+	curseg->alloc_type = SSR;
+	__next_free_blkoff(sbi, curseg, 0);
+
+	sum_page = f2fs_get_sum_page(sbi, new_segno);
+	sum_node = (struct f2fs_summary_block *)page_address(sum_page);
+	memcpy(curseg->sum_blk, sum_node, SUM_ENTRY_SIZE);
+	f2fs_put_page(sum_page, 1);
+}
+
+static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
+	unsigned segno = NULL_SEGNO;
+	int i, cnt;
+	bool reversed = false;
+
+	/* f2fs_need_SSR() already forces to do this */
+	if (v_ops->get_victim(sbi, &segno, BG_GC, type, SSR)) {
+		curseg->next_segno = segno;
+		return 1;
+	}
+
+	/* For node segments, let's do SSR more intensively */
+	if (IS_NODESEG(type)) {
+		if (type >= CURSEG_WARM_NODE) {
+			reversed = true;
+			i = CURSEG_COLD_NODE;
+		} else {
+			i = CURSEG_HOT_NODE;
+		}
+		cnt = NR_CURSEG_NODE_TYPE;
+	} else {
+		if (type >= CURSEG_WARM_DATA) {
+			reversed = true;
+			i = CURSEG_COLD_DATA;
+		} else {
+			i = CURSEG_HOT_DATA;
+		}
+		cnt = NR_CURSEG_DATA_TYPE;
+	}
+
+	for (; cnt-- > 0; reversed ? i-- : i++) {
+		if (i == type)
+			continue;
+		if (v_ops->get_victim(sbi, &segno, BG_GC, i, SSR)) {
+			curseg->next_segno = segno;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * flush out current segment and replace it with new segment
+ * This function should be returned with success, otherwise BUG
+ */
+static void allocate_segment_by_default(struct f2fs_sb_info *sbi,
+						int type, bool force)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+
+	if (force)
+		new_curseg(sbi, type, true);
+	else if (!is_set_ckpt_flags(sbi, CP_CRC_RECOVERY_FLAG) &&
+					type == CURSEG_WARM_NODE)
+		new_curseg(sbi, type, false);
+	else if (curseg->alloc_type == LFS && is_next_segment_free(sbi, type))
+		new_curseg(sbi, type, false);
+	else if (f2fs_need_SSR(sbi) && get_ssr_segment(sbi, type))
+		change_curseg(sbi, type);
+	else
+		new_curseg(sbi, type, false);
+
+	stat_inc_seg_type(sbi, curseg);
+}
+
+void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi)
+{
+	struct curseg_info *curseg;
+	unsigned int old_segno;
+	int i;
+
+	down_write(&SIT_I(sbi)->sentry_lock);
+
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
+		curseg = CURSEG_I(sbi, i);
+		old_segno = curseg->segno;
+		SIT_I(sbi)->s_ops->allocate_segment(sbi, i, true);
+		locate_dirty_segment(sbi, old_segno);
+	}
+
+	up_write(&SIT_I(sbi)->sentry_lock);
+}
+
+static const struct segment_allocation default_salloc_ops = {
+	.allocate_segment = allocate_segment_by_default,
+};
+
+bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
+						struct cp_control *cpc)
+{
+	__u64 trim_start = cpc->trim_start;
+	bool has_candidate = false;
+
+	down_write(&SIT_I(sbi)->sentry_lock);
+	for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++) {
+		if (add_discard_addrs(sbi, cpc, true)) {
+			has_candidate = true;
+			break;
+		}
+	}
+	up_write(&SIT_I(sbi)->sentry_lock);
+
+	cpc->trim_start = trim_start;
+	return has_candidate;
+}
+
+static unsigned int __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy,
+					unsigned int start, unsigned int end)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	struct discard_cmd *dc;
+	struct blk_plug plug;
+	int issued;
+	unsigned int trimmed = 0;
+
+next:
+	issued = 0;
+
+	mutex_lock(&dcc->cmd_lock);
+	if (unlikely(dcc->rbtree_check))
+		f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
+								&dcc->root));
+
+	dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
+					NULL, start,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true);
+	if (!dc)
+		dc = next_dc;
+
+	blk_start_plug(&plug);
+
+	while (dc && dc->lstart <= end) {
+		struct rb_node *node;
+		int err = 0;
+
+		if (dc->len < dpolicy->granularity)
+			goto skip;
+
+		if (dc->state != D_PREP) {
+			list_move_tail(&dc->list, &dcc->fstrim_list);
+			goto skip;
+		}
+
+		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
+
+		if (issued >= dpolicy->max_requests) {
+			start = dc->lstart + dc->len;
+
+			if (err)
+				__remove_discard_cmd(sbi, dc);
+
+			blk_finish_plug(&plug);
+			mutex_unlock(&dcc->cmd_lock);
+			trimmed += __wait_all_discard_cmd(sbi, NULL);
+			congestion_wait(BLK_RW_ASYNC, HZ/50);
+			goto next;
+		}
+skip:
+		node = rb_next(&dc->rb_node);
+		if (err)
+			__remove_discard_cmd(sbi, dc);
+		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+
+		if (fatal_signal_pending(current))
+			break;
+	}
+
+	blk_finish_plug(&plug);
+	mutex_unlock(&dcc->cmd_lock);
+
+	return trimmed;
+}
+
+int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
+{
+	__u64 start = F2FS_BYTES_TO_BLK(range->start);
+	__u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
+	unsigned int start_segno, end_segno;
+	block_t start_block, end_block;
+	struct cp_control cpc;
+	struct discard_policy dpolicy;
+	unsigned long long trimmed = 0;
+	int err = 0;
+	bool need_align = test_opt(sbi, LFS) && sbi->segs_per_sec > 1;
+
+	if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
+		return -EINVAL;
+
+	if (end < MAIN_BLKADDR(sbi))
+		goto out;
+
+	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
+		f2fs_msg(sbi->sb, KERN_WARNING,
+			"Found FS corruption, run fsck to fix.");
+		return -EFSCORRUPTED;
+	}
+
+	/* start/end segment number in main_area */
+	start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
+	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
+						GET_SEGNO(sbi, end);
+	if (need_align) {
+		start_segno = rounddown(start_segno, sbi->segs_per_sec);
+		end_segno = roundup(end_segno + 1, sbi->segs_per_sec) - 1;
+	}
+
+	cpc.reason = CP_DISCARD;
+	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
+	cpc.trim_start = start_segno;
+	cpc.trim_end = end_segno;
+
+	if (sbi->discard_blks == 0)
+		goto out;
+
+	mutex_lock(&sbi->gc_mutex);
+	err = f2fs_write_checkpoint(sbi, &cpc);
+	mutex_unlock(&sbi->gc_mutex);
+	if (err)
+		goto out;
+
+	/*
+	 * We filed discard candidates, but actually we don't need to wait for
+	 * all of them, since they'll be issued in idle time along with runtime
+	 * discard option. User configuration looks like using runtime discard
+	 * or periodic fstrim instead of it.
+	 */
+	if (f2fs_realtime_discard_enable(sbi))
+		goto out;
+
+	start_block = START_BLOCK(sbi, start_segno);
+	end_block = START_BLOCK(sbi, end_segno + 1);
+
+	__init_discard_policy(sbi, &dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
+	trimmed = __issue_discard_cmd_range(sbi, &dpolicy,
+					start_block, end_block);
+
+	trimmed += __wait_discard_cmd_range(sbi, &dpolicy,
+					start_block, end_block);
+out:
+	if (!err)
+		range->len = F2FS_BLK_TO_BYTES(trimmed);
+	return err;
+}
+
+static bool __has_curseg_space(struct f2fs_sb_info *sbi, int type)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	if (curseg->next_blkoff < sbi->blocks_per_seg)
+		return true;
+	return false;
+}
+
+int f2fs_rw_hint_to_seg_type(enum rw_hint hint)
+{
+	switch (hint) {
+	case WRITE_LIFE_SHORT:
+		return CURSEG_HOT_DATA;
+	case WRITE_LIFE_EXTREME:
+		return CURSEG_COLD_DATA;
+	default:
+		return CURSEG_WARM_DATA;
+	}
+}
+
+/* This returns write hints for each segment type. This hints will be
+ * passed down to block layer. There are mapping tables which depend on
+ * the mount option 'whint_mode'.
+ *
+ * 1) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.
+ *
+ * 2) whint_mode=user-based. F2FS tries to pass down hints given by users.
+ *
+ * User                  F2FS                     Block
+ * ----                  ----                     -----
+ *                       META                     WRITE_LIFE_NOT_SET
+ *                       HOT_NODE                 "
+ *                       WARM_NODE                "
+ *                       COLD_NODE                "
+ * ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
+ * extension list        "                        "
+ *
+ * -- buffered io
+ * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
+ * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
+ * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
+ * WRITE_LIFE_NONE       "                        "
+ * WRITE_LIFE_MEDIUM     "                        "
+ * WRITE_LIFE_LONG       "                        "
+ *
+ * -- direct io
+ * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
+ * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
+ * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
+ * WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE
+ * WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM
+ * WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG
+ *
+ * 3) whint_mode=fs-based. F2FS passes down hints with its policy.
+ *
+ * User                  F2FS                     Block
+ * ----                  ----                     -----
+ *                       META                     WRITE_LIFE_MEDIUM;
+ *                       HOT_NODE                 WRITE_LIFE_NOT_SET
+ *                       WARM_NODE                "
+ *                       COLD_NODE                WRITE_LIFE_NONE
+ * ioctl(COLD)           COLD_DATA                WRITE_LIFE_EXTREME
+ * extension list        "                        "
+ *
+ * -- buffered io
+ * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
+ * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
+ * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_LONG
+ * WRITE_LIFE_NONE       "                        "
+ * WRITE_LIFE_MEDIUM     "                        "
+ * WRITE_LIFE_LONG       "                        "
+ *
+ * -- direct io
+ * WRITE_LIFE_EXTREME    COLD_DATA                WRITE_LIFE_EXTREME
+ * WRITE_LIFE_SHORT      HOT_DATA                 WRITE_LIFE_SHORT
+ * WRITE_LIFE_NOT_SET    WARM_DATA                WRITE_LIFE_NOT_SET
+ * WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE
+ * WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM
+ * WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG
+ */
+
+enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
+				enum page_type type, enum temp_type temp)
+{
+	if (F2FS_OPTION(sbi).whint_mode == WHINT_MODE_USER) {
+		if (type == DATA) {
+			if (temp == WARM)
+				return WRITE_LIFE_NOT_SET;
+			else if (temp == HOT)
+				return WRITE_LIFE_SHORT;
+			else if (temp == COLD)
+				return WRITE_LIFE_EXTREME;
+		} else {
+			return WRITE_LIFE_NOT_SET;
+		}
+	} else if (F2FS_OPTION(sbi).whint_mode == WHINT_MODE_FS) {
+		if (type == DATA) {
+			if (temp == WARM)
+				return WRITE_LIFE_LONG;
+			else if (temp == HOT)
+				return WRITE_LIFE_SHORT;
+			else if (temp == COLD)
+				return WRITE_LIFE_EXTREME;
+		} else if (type == NODE) {
+			if (temp == WARM || temp == HOT)
+				return WRITE_LIFE_NOT_SET;
+			else if (temp == COLD)
+				return WRITE_LIFE_NONE;
+		} else if (type == META) {
+			return WRITE_LIFE_MEDIUM;
+		}
+	}
+	return WRITE_LIFE_NOT_SET;
+}
+
+static int __get_segment_type_2(struct f2fs_io_info *fio)
+{
+	if (fio->type == DATA)
+		return CURSEG_HOT_DATA;
+	else
+		return CURSEG_HOT_NODE;
+}
+
+static int __get_segment_type_4(struct f2fs_io_info *fio)
+{
+	if (fio->type == DATA) {
+		struct inode *inode = fio->page->mapping->host;
+
+		if (S_ISDIR(inode->i_mode))
+			return CURSEG_HOT_DATA;
+		else
+			return CURSEG_COLD_DATA;
+	} else {
+		if (IS_DNODE(fio->page) && is_cold_node(fio->page))
+			return CURSEG_WARM_NODE;
+		else
+			return CURSEG_COLD_NODE;
+	}
+}
+
+static int __get_segment_type_6(struct f2fs_io_info *fio)
+{
+	if (fio->type == DATA) {
+		struct inode *inode = fio->page->mapping->host;
+
+		if (is_cold_data(fio->page) || file_is_cold(inode))
+			return CURSEG_COLD_DATA;
+		if (file_is_hot(inode) ||
+				is_inode_flag_set(inode, FI_HOT_DATA) ||
+				f2fs_is_atomic_file(inode) ||
+				f2fs_is_volatile_file(inode))
+			return CURSEG_HOT_DATA;
+		return f2fs_rw_hint_to_seg_type(inode->i_write_hint);
+	} else {
+		if (IS_DNODE(fio->page))
+			return is_cold_node(fio->page) ? CURSEG_WARM_NODE :
+						CURSEG_HOT_NODE;
+		return CURSEG_COLD_NODE;
+	}
+}
+
+static int __get_segment_type(struct f2fs_io_info *fio)
+{
+	int type = 0;
+
+	switch (F2FS_OPTION(fio->sbi).active_logs) {
+	case 2:
+		type = __get_segment_type_2(fio);
+		break;
+	case 4:
+		type = __get_segment_type_4(fio);
+		break;
+	case 6:
+		type = __get_segment_type_6(fio);
+		break;
+	default:
+		f2fs_bug_on(fio->sbi, true);
+	}
+
+	if (IS_HOT(type))
+		fio->temp = HOT;
+	else if (IS_WARM(type))
+		fio->temp = WARM;
+	else
+		fio->temp = COLD;
+	return type;
+}
+
+void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
+		block_t old_blkaddr, block_t *new_blkaddr,
+		struct f2fs_summary *sum, int type,
+		struct f2fs_io_info *fio, bool add_list)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+
+	down_read(&SM_I(sbi)->curseg_lock);
+
+	mutex_lock(&curseg->curseg_mutex);
+	down_write(&sit_i->sentry_lock);
+
+	*new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
+
+	f2fs_wait_discard_bio(sbi, *new_blkaddr);
+
+	/*
+	 * __add_sum_entry should be resided under the curseg_mutex
+	 * because, this function updates a summary entry in the
+	 * current summary block.
+	 */
+	__add_sum_entry(sbi, type, sum);
+
+	__refresh_next_blkoff(sbi, curseg);
+
+	stat_inc_block_count(sbi, curseg);
+
+	/*
+	 * SIT information should be updated before segment allocation,
+	 * since SSR needs latest valid block information.
+	 */
+	update_sit_entry(sbi, *new_blkaddr, 1);
+	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
+		update_sit_entry(sbi, old_blkaddr, -1);
+
+	if (!__has_curseg_space(sbi, type))
+		sit_i->s_ops->allocate_segment(sbi, type, false);
+
+	/*
+	 * segment dirty status should be updated after segment allocation,
+	 * so we just need to update status only one time after previous
+	 * segment being closed.
+	 */
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, old_blkaddr));
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, *new_blkaddr));
+
+	up_write(&sit_i->sentry_lock);
+
+	if (page && IS_NODESEG(type)) {
+		fill_node_footer_blkaddr(page, NEXT_FREE_BLKADDR(sbi, curseg));
+
+		f2fs_inode_chksum_set(sbi, page);
+	}
+
+	if (add_list) {
+		struct f2fs_bio_info *io;
+
+		INIT_LIST_HEAD(&fio->list);
+		fio->in_list = true;
+		fio->retry = false;
+		io = sbi->write_io[fio->type] + fio->temp;
+		spin_lock(&io->io_lock);
+		list_add_tail(&fio->list, &io->io_list);
+		spin_unlock(&io->io_lock);
+	}
+
+	mutex_unlock(&curseg->curseg_mutex);
+
+	up_read(&SM_I(sbi)->curseg_lock);
+}
+
+static void update_device_state(struct f2fs_io_info *fio)
+{
+	struct f2fs_sb_info *sbi = fio->sbi;
+	unsigned int devidx;
+
+	if (!f2fs_is_multi_device(sbi))
+		return;
+
+	devidx = f2fs_target_device_index(sbi, fio->new_blkaddr);
+
+	/* update device state for fsync */
+	f2fs_set_dirty_device(sbi, fio->ino, devidx, FLUSH_INO);
+
+	/* update device state for checkpoint */
+	if (!f2fs_test_bit(devidx, (char *)&sbi->dirty_device)) {
+		spin_lock(&sbi->dev_lock);
+		f2fs_set_bit(devidx, (char *)&sbi->dirty_device);
+		spin_unlock(&sbi->dev_lock);
+	}
+}
+
+static void do_write_page(struct f2fs_summary *sum, struct f2fs_io_info *fio)
+{
+	int type = __get_segment_type(fio);
+	bool keep_order = (test_opt(fio->sbi, LFS) && type == CURSEG_COLD_DATA);
+
+	if (keep_order)
+		down_read(&fio->sbi->io_order_lock);
+reallocate:
+	f2fs_allocate_data_block(fio->sbi, fio->page, fio->old_blkaddr,
+			&fio->new_blkaddr, sum, type, fio, true);
+	if (GET_SEGNO(fio->sbi, fio->old_blkaddr) != NULL_SEGNO)
+		invalidate_mapping_pages(META_MAPPING(fio->sbi),
+					fio->old_blkaddr, fio->old_blkaddr);
+
+	/* writeout dirty page into bdev */
+	f2fs_submit_page_write(fio);
+	if (fio->retry) {
+		fio->old_blkaddr = fio->new_blkaddr;
+		goto reallocate;
+	}
+
+	update_device_state(fio);
+
+	if (keep_order)
+		up_read(&fio->sbi->io_order_lock);
+}
+
+void f2fs_do_write_meta_page(struct f2fs_sb_info *sbi, struct page *page,
+					enum iostat_type io_type)
+{
+	struct f2fs_io_info fio = {
+		.sbi = sbi,
+		.type = META,
+		.temp = HOT,
+		.op = REQ_OP_WRITE,
+		.op_flags = REQ_SYNC | REQ_META | REQ_PRIO,
+		.old_blkaddr = page->index,
+		.new_blkaddr = page->index,
+		.page = page,
+		.encrypted_page = NULL,
+		.in_list = false,
+	};
+
+	if (unlikely(page->index >= MAIN_BLKADDR(sbi)))
+		fio.op_flags &= ~REQ_META;
+
+	set_page_writeback(page);
+	ClearPageError(page);
+	f2fs_submit_page_write(&fio);
+
+	f2fs_update_iostat(sbi, io_type, F2FS_BLKSIZE);
+}
+
+void f2fs_do_write_node_page(unsigned int nid, struct f2fs_io_info *fio)
+{
+	struct f2fs_summary sum;
+
+	set_summary(&sum, nid, 0, 0);
+	do_write_page(&sum, fio);
+
+	f2fs_update_iostat(fio->sbi, fio->io_type, F2FS_BLKSIZE);
+}
+
+void f2fs_outplace_write_data(struct dnode_of_data *dn,
+					struct f2fs_io_info *fio)
+{
+	struct f2fs_sb_info *sbi = fio->sbi;
+	struct f2fs_summary sum;
+
+	f2fs_bug_on(sbi, dn->data_blkaddr == NULL_ADDR);
+	set_summary(&sum, dn->nid, dn->ofs_in_node, fio->version);
+	do_write_page(&sum, fio);
+	f2fs_update_data_blkaddr(dn, fio->new_blkaddr);
+
+	f2fs_update_iostat(sbi, fio->io_type, F2FS_BLKSIZE);
+}
+
+int f2fs_inplace_write_data(struct f2fs_io_info *fio)
+{
+	int err;
+	struct f2fs_sb_info *sbi = fio->sbi;
+	unsigned int segno;
+
+	fio->new_blkaddr = fio->old_blkaddr;
+	/* i/o temperature is needed for passing down write hints */
+	__get_segment_type(fio);
+
+	segno = GET_SEGNO(sbi, fio->new_blkaddr);
+
+	if (!IS_DATASEG(get_seg_entry(sbi, segno)->type)) {
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		return -EFSCORRUPTED;
+	}
+
+	stat_inc_inplace_blocks(fio->sbi);
+
+	err = f2fs_submit_page_bio(fio);
+	if (!err)
+		update_device_state(fio);
+
+	f2fs_update_iostat(fio->sbi, fio->io_type, F2FS_BLKSIZE);
+
+	return err;
+}
+
+static inline int __f2fs_get_curseg(struct f2fs_sb_info *sbi,
+						unsigned int segno)
+{
+	int i;
+
+	for (i = CURSEG_HOT_DATA; i < NO_CHECK_TYPE; i++) {
+		if (CURSEG_I(sbi, i)->segno == segno)
+			break;
+	}
+	return i;
+}
+
+void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+				block_t old_blkaddr, block_t new_blkaddr,
+				bool recover_curseg, bool recover_newaddr)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct curseg_info *curseg;
+	unsigned int segno, old_cursegno;
+	struct seg_entry *se;
+	int type;
+	unsigned short old_blkoff;
+
+	segno = GET_SEGNO(sbi, new_blkaddr);
+	se = get_seg_entry(sbi, segno);
+	type = se->type;
+
+	down_write(&SM_I(sbi)->curseg_lock);
+
+	if (!recover_curseg) {
+		/* for recovery flow */
+		if (se->valid_blocks == 0 && !IS_CURSEG(sbi, segno)) {
+			if (old_blkaddr == NULL_ADDR)
+				type = CURSEG_COLD_DATA;
+			else
+				type = CURSEG_WARM_DATA;
+		}
+	} else {
+		if (IS_CURSEG(sbi, segno)) {
+			/* se->type is volatile as SSR allocation */
+			type = __f2fs_get_curseg(sbi, segno);
+			f2fs_bug_on(sbi, type == NO_CHECK_TYPE);
+		} else {
+			type = CURSEG_WARM_DATA;
+		}
+	}
+
+	f2fs_bug_on(sbi, !IS_DATASEG(type));
+	curseg = CURSEG_I(sbi, type);
+
+	mutex_lock(&curseg->curseg_mutex);
+	down_write(&sit_i->sentry_lock);
+
+	old_cursegno = curseg->segno;
+	old_blkoff = curseg->next_blkoff;
+
+	/* change the current segment */
+	if (segno != curseg->segno) {
+		curseg->next_segno = segno;
+		change_curseg(sbi, type);
+	}
+
+	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
+	__add_sum_entry(sbi, type, sum);
+
+	if (!recover_curseg || recover_newaddr)
+		update_sit_entry(sbi, new_blkaddr, 1);
+	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO) {
+		invalidate_mapping_pages(META_MAPPING(sbi),
+					old_blkaddr, old_blkaddr);
+		update_sit_entry(sbi, old_blkaddr, -1);
+	}
+
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, old_blkaddr));
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, new_blkaddr));
+
+	locate_dirty_segment(sbi, old_cursegno);
+
+	if (recover_curseg) {
+		if (old_cursegno != curseg->segno) {
+			curseg->next_segno = old_cursegno;
+			change_curseg(sbi, type);
+		}
+		curseg->next_blkoff = old_blkoff;
+	}
+
+	up_write(&sit_i->sentry_lock);
+	mutex_unlock(&curseg->curseg_mutex);
+	up_write(&SM_I(sbi)->curseg_lock);
+}
+
+void f2fs_replace_block(struct f2fs_sb_info *sbi, struct dnode_of_data *dn,
+				block_t old_addr, block_t new_addr,
+				unsigned char version, bool recover_curseg,
+				bool recover_newaddr)
+{
+	struct f2fs_summary sum;
+
+	set_summary(&sum, dn->nid, dn->ofs_in_node, version);
+
+	f2fs_do_replace_block(sbi, &sum, old_addr, new_addr,
+					recover_curseg, recover_newaddr);
+
+	f2fs_update_data_blkaddr(dn, new_addr);
+}
+
+void f2fs_wait_on_page_writeback(struct page *page,
+				enum page_type type, bool ordered)
+{
+	if (PageWriteback(page)) {
+		struct f2fs_sb_info *sbi = F2FS_P_SB(page);
+
+		f2fs_submit_merged_write_cond(sbi, page->mapping->host,
+						0, page->index, type);
+		if (ordered)
+			wait_on_page_writeback(page);
+		else
+			wait_for_stable_page(page);
+	}
+}
+
+void f2fs_wait_on_block_writeback(struct inode *inode, block_t blkaddr)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct page *cpage;
+
+	if (!f2fs_post_read_required(inode))
+		return;
+
+	if (!is_valid_data_blkaddr(sbi, blkaddr))
+		return;
+
+	cpage = find_lock_page(META_MAPPING(sbi), blkaddr);
+	if (cpage) {
+		f2fs_wait_on_page_writeback(cpage, DATA, true);
+		f2fs_put_page(cpage, 1);
+	}
+}
+
+static int read_compacted_summaries(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
+	struct curseg_info *seg_i;
+	unsigned char *kaddr;
+	struct page *page;
+	block_t start;
+	int i, j, offset;
+
+	start = start_sum_block(sbi);
+
+	page = f2fs_get_meta_page(sbi, start++);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+	kaddr = (unsigned char *)page_address(page);
+
+	/* Step 1: restore nat cache */
+	seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	memcpy(seg_i->journal, kaddr, SUM_JOURNAL_SIZE);
+
+	/* Step 2: restore sit cache */
+	seg_i = CURSEG_I(sbi, CURSEG_COLD_DATA);
+	memcpy(seg_i->journal, kaddr + SUM_JOURNAL_SIZE, SUM_JOURNAL_SIZE);
+	offset = 2 * SUM_JOURNAL_SIZE;
+
+	/* Step 3: restore summary entries */
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
+		unsigned short blk_off;
+		unsigned int segno;
+
+		seg_i = CURSEG_I(sbi, i);
+		segno = le32_to_cpu(ckpt->cur_data_segno[i]);
+		blk_off = le16_to_cpu(ckpt->cur_data_blkoff[i]);
+		seg_i->next_segno = segno;
+		reset_curseg(sbi, i, 0);
+		seg_i->alloc_type = ckpt->alloc_type[i];
+		seg_i->next_blkoff = blk_off;
+
+		if (seg_i->alloc_type == SSR)
+			blk_off = sbi->blocks_per_seg;
+
+		for (j = 0; j < blk_off; j++) {
+			struct f2fs_summary *s;
+			s = (struct f2fs_summary *)(kaddr + offset);
+			seg_i->sum_blk->entries[j] = *s;
+			offset += SUMMARY_SIZE;
+			if (offset + SUMMARY_SIZE <= PAGE_SIZE -
+						SUM_FOOTER_SIZE)
+				continue;
+
+			f2fs_put_page(page, 1);
+			page = NULL;
+
+			page = f2fs_get_meta_page(sbi, start++);
+			if (IS_ERR(page))
+				return PTR_ERR(page);
+			kaddr = (unsigned char *)page_address(page);
+			offset = 0;
+		}
+	}
+	f2fs_put_page(page, 1);
+	return 0;
+}
+
+static int read_normal_summaries(struct f2fs_sb_info *sbi, int type)
+{
+	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
+	struct f2fs_summary_block *sum;
+	struct curseg_info *curseg;
+	struct page *new;
+	unsigned short blk_off;
+	unsigned int segno = 0;
+	block_t blk_addr = 0;
+	int err = 0;
+
+	/* get segment number and block addr */
+	if (IS_DATASEG(type)) {
+		segno = le32_to_cpu(ckpt->cur_data_segno[type]);
+		blk_off = le16_to_cpu(ckpt->cur_data_blkoff[type -
+							CURSEG_HOT_DATA]);
+		if (__exist_node_summaries(sbi))
+			blk_addr = sum_blk_addr(sbi, NR_CURSEG_TYPE, type);
+		else
+			blk_addr = sum_blk_addr(sbi, NR_CURSEG_DATA_TYPE, type);
+	} else {
+		segno = le32_to_cpu(ckpt->cur_node_segno[type -
+							CURSEG_HOT_NODE]);
+		blk_off = le16_to_cpu(ckpt->cur_node_blkoff[type -
+							CURSEG_HOT_NODE]);
+		if (__exist_node_summaries(sbi))
+			blk_addr = sum_blk_addr(sbi, NR_CURSEG_NODE_TYPE,
+							type - CURSEG_HOT_NODE);
+		else
+			blk_addr = GET_SUM_BLOCK(sbi, segno);
+	}
+
+	new = f2fs_get_meta_page(sbi, blk_addr);
+	if (IS_ERR(new))
+		return PTR_ERR(new);
+	sum = (struct f2fs_summary_block *)page_address(new);
+
+	if (IS_NODESEG(type)) {
+		if (__exist_node_summaries(sbi)) {
+			struct f2fs_summary *ns = &sum->entries[0];
+			int i;
+			for (i = 0; i < sbi->blocks_per_seg; i++, ns++) {
+				ns->version = 0;
+				ns->ofs_in_node = 0;
+			}
+		} else {
+			err = f2fs_restore_node_summary(sbi, segno, sum);
+			if (err)
+				goto out;
+		}
+	}
+
+	/* set uncompleted segment to curseg */
+	curseg = CURSEG_I(sbi, type);
+	mutex_lock(&curseg->curseg_mutex);
+
+	/* update journal info */
+	down_write(&curseg->journal_rwsem);
+	memcpy(curseg->journal, &sum->journal, SUM_JOURNAL_SIZE);
+	up_write(&curseg->journal_rwsem);
+
+	memcpy(curseg->sum_blk->entries, sum->entries, SUM_ENTRY_SIZE);
+	memcpy(&curseg->sum_blk->footer, &sum->footer, SUM_FOOTER_SIZE);
+	curseg->next_segno = segno;
+	reset_curseg(sbi, type, 0);
+	curseg->alloc_type = ckpt->alloc_type[type];
+	curseg->next_blkoff = blk_off;
+	mutex_unlock(&curseg->curseg_mutex);
+out:
+	f2fs_put_page(new, 1);
+	return err;
+}
+
+static int restore_curseg_summaries(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_journal *sit_j = CURSEG_I(sbi, CURSEG_COLD_DATA)->journal;
+	struct f2fs_journal *nat_j = CURSEG_I(sbi, CURSEG_HOT_DATA)->journal;
+	int type = CURSEG_HOT_DATA;
+	int err;
+
+	if (is_set_ckpt_flags(sbi, CP_COMPACT_SUM_FLAG)) {
+		int npages = f2fs_npages_for_summary_flush(sbi, true);
+
+		if (npages >= 2)
+			f2fs_ra_meta_pages(sbi, start_sum_block(sbi), npages,
+							META_CP, true);
+
+		/* restore for compacted data summary */
+		err = read_compacted_summaries(sbi);
+		if (err)
+			return err;
+		type = CURSEG_HOT_NODE;
+	}
+
+	if (__exist_node_summaries(sbi))
+		f2fs_ra_meta_pages(sbi, sum_blk_addr(sbi, NR_CURSEG_TYPE, type),
+					NR_CURSEG_TYPE - type, META_CP, true);
+
+	for (; type <= CURSEG_COLD_NODE; type++) {
+		err = read_normal_summaries(sbi, type);
+		if (err)
+			return err;
+	}
+
+	/* sanity check for summary blocks */
+	if (nats_in_cursum(nat_j) > NAT_JOURNAL_ENTRIES ||
+			sits_in_cursum(sit_j) > SIT_JOURNAL_ENTRIES)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void write_compacted_summaries(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	struct page *page;
+	unsigned char *kaddr;
+	struct f2fs_summary *summary;
+	struct curseg_info *seg_i;
+	int written_size = 0;
+	int i, j;
+
+	page = f2fs_grab_meta_page(sbi, blkaddr++);
+	kaddr = (unsigned char *)page_address(page);
+	memset(kaddr, 0, PAGE_SIZE);
+
+	/* Step 1: write nat cache */
+	seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	memcpy(kaddr, seg_i->journal, SUM_JOURNAL_SIZE);
+	written_size += SUM_JOURNAL_SIZE;
+
+	/* Step 2: write sit cache */
+	seg_i = CURSEG_I(sbi, CURSEG_COLD_DATA);
+	memcpy(kaddr + written_size, seg_i->journal, SUM_JOURNAL_SIZE);
+	written_size += SUM_JOURNAL_SIZE;
+
+	/* Step 3: write summary entries */
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
+		unsigned short blkoff;
+		seg_i = CURSEG_I(sbi, i);
+		if (sbi->ckpt->alloc_type[i] == SSR)
+			blkoff = sbi->blocks_per_seg;
+		else
+			blkoff = curseg_blkoff(sbi, i);
+
+		for (j = 0; j < blkoff; j++) {
+			if (!page) {
+				page = f2fs_grab_meta_page(sbi, blkaddr++);
+				kaddr = (unsigned char *)page_address(page);
+				memset(kaddr, 0, PAGE_SIZE);
+				written_size = 0;
+			}
+			summary = (struct f2fs_summary *)(kaddr + written_size);
+			*summary = seg_i->sum_blk->entries[j];
+			written_size += SUMMARY_SIZE;
+
+			if (written_size + SUMMARY_SIZE <= PAGE_SIZE -
+							SUM_FOOTER_SIZE)
+				continue;
+
+			set_page_dirty(page);
+			f2fs_put_page(page, 1);
+			page = NULL;
+		}
+	}
+	if (page) {
+		set_page_dirty(page);
+		f2fs_put_page(page, 1);
+	}
+}
+
+static void write_normal_summaries(struct f2fs_sb_info *sbi,
+					block_t blkaddr, int type)
+{
+	int i, end;
+	if (IS_DATASEG(type))
+		end = type + NR_CURSEG_DATA_TYPE;
+	else
+		end = type + NR_CURSEG_NODE_TYPE;
+
+	for (i = type; i < end; i++)
+		write_current_sum_page(sbi, i, blkaddr + (i - type));
+}
+
+void f2fs_write_data_summaries(struct f2fs_sb_info *sbi, block_t start_blk)
+{
+	if (is_set_ckpt_flags(sbi, CP_COMPACT_SUM_FLAG))
+		write_compacted_summaries(sbi, start_blk);
+	else
+		write_normal_summaries(sbi, start_blk, CURSEG_HOT_DATA);
+}
+
+void f2fs_write_node_summaries(struct f2fs_sb_info *sbi, block_t start_blk)
+{
+	write_normal_summaries(sbi, start_blk, CURSEG_HOT_NODE);
+}
+
+int f2fs_lookup_journal_in_cursum(struct f2fs_journal *journal, int type,
+					unsigned int val, int alloc)
+{
+	int i;
+
+	if (type == NAT_JOURNAL) {
+		for (i = 0; i < nats_in_cursum(journal); i++) {
+			if (le32_to_cpu(nid_in_journal(journal, i)) == val)
+				return i;
+		}
+		if (alloc && __has_cursum_space(journal, 1, NAT_JOURNAL))
+			return update_nats_in_cursum(journal, 1);
+	} else if (type == SIT_JOURNAL) {
+		for (i = 0; i < sits_in_cursum(journal); i++)
+			if (le32_to_cpu(segno_in_journal(journal, i)) == val)
+				return i;
+		if (alloc && __has_cursum_space(journal, 1, SIT_JOURNAL))
+			return update_sits_in_cursum(journal, 1);
+	}
+	return -1;
+}
+
+static struct page *get_current_sit_page(struct f2fs_sb_info *sbi,
+					unsigned int segno)
+{
+	return f2fs_get_meta_page_nofail(sbi, current_sit_addr(sbi, segno));
+}
+
+static struct page *get_next_sit_page(struct f2fs_sb_info *sbi,
+					unsigned int start)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct page *page;
+	pgoff_t src_off, dst_off;
+
+	src_off = current_sit_addr(sbi, start);
+	dst_off = next_sit_addr(sbi, src_off);
+
+	page = f2fs_grab_meta_page(sbi, dst_off);
+	seg_info_to_sit_page(sbi, page, start);
+
+	set_page_dirty(page);
+	set_to_next_sit(sit_i, start);
+
+	return page;
+}
+
+static struct sit_entry_set *grab_sit_entry_set(void)
+{
+	struct sit_entry_set *ses =
+			f2fs_kmem_cache_alloc(sit_entry_set_slab, GFP_NOFS);
+
+	ses->entry_cnt = 0;
+	INIT_LIST_HEAD(&ses->set_list);
+	return ses;
+}
+
+static void release_sit_entry_set(struct sit_entry_set *ses)
+{
+	list_del(&ses->set_list);
+	kmem_cache_free(sit_entry_set_slab, ses);
+}
+
+static void adjust_sit_entry_set(struct sit_entry_set *ses,
+						struct list_head *head)
+{
+	struct sit_entry_set *next = ses;
+
+	if (list_is_last(&ses->set_list, head))
+		return;
+
+	list_for_each_entry_continue(next, head, set_list)
+		if (ses->entry_cnt <= next->entry_cnt)
+			break;
+
+	list_move_tail(&ses->set_list, &next->set_list);
+}
+
+static void add_sit_entry(unsigned int segno, struct list_head *head)
+{
+	struct sit_entry_set *ses;
+	unsigned int start_segno = START_SEGNO(segno);
+
+	list_for_each_entry(ses, head, set_list) {
+		if (ses->start_segno == start_segno) {
+			ses->entry_cnt++;
+			adjust_sit_entry_set(ses, head);
+			return;
+		}
+	}
+
+	ses = grab_sit_entry_set();
+
+	ses->start_segno = start_segno;
+	ses->entry_cnt++;
+	list_add(&ses->set_list, head);
+}
+
+static void add_sits_in_set(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_sm_info *sm_info = SM_I(sbi);
+	struct list_head *set_list = &sm_info->sit_entry_set;
+	unsigned long *bitmap = SIT_I(sbi)->dirty_sentries_bitmap;
+	unsigned int segno;
+
+	for_each_set_bit(segno, bitmap, MAIN_SEGS(sbi))
+		add_sit_entry(segno, set_list);
+}
+
+static void remove_sits_in_journal(struct f2fs_sb_info *sbi)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA);
+	struct f2fs_journal *journal = curseg->journal;
+	int i;
+
+	down_write(&curseg->journal_rwsem);
+	for (i = 0; i < sits_in_cursum(journal); i++) {
+		unsigned int segno;
+		bool dirtied;
+
+		segno = le32_to_cpu(segno_in_journal(journal, i));
+		dirtied = __mark_sit_entry_dirty(sbi, segno);
+
+		if (!dirtied)
+			add_sit_entry(segno, &SM_I(sbi)->sit_entry_set);
+	}
+	update_sits_in_cursum(journal, -i);
+	up_write(&curseg->journal_rwsem);
+}
+
+/*
+ * CP calls this function, which flushes SIT entries including sit_journal,
+ * and moves prefree segs to free segs.
+ */
+void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned long *bitmap = sit_i->dirty_sentries_bitmap;
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA);
+	struct f2fs_journal *journal = curseg->journal;
+	struct sit_entry_set *ses, *tmp;
+	struct list_head *head = &SM_I(sbi)->sit_entry_set;
+	bool to_journal = true;
+	struct seg_entry *se;
+
+	down_write(&sit_i->sentry_lock);
+
+	if (!sit_i->dirty_sentries)
+		goto out;
+
+	/*
+	 * add and account sit entries of dirty bitmap in sit entry
+	 * set temporarily
+	 */
+	add_sits_in_set(sbi);
+
+	/*
+	 * if there are no enough space in journal to store dirty sit
+	 * entries, remove all entries from journal and add and account
+	 * them in sit entry set.
+	 */
+	if (!__has_cursum_space(journal, sit_i->dirty_sentries, SIT_JOURNAL))
+		remove_sits_in_journal(sbi);
+
+	/*
+	 * there are two steps to flush sit entries:
+	 * #1, flush sit entries to journal in current cold data summary block.
+	 * #2, flush sit entries to sit page.
+	 */
+	list_for_each_entry_safe(ses, tmp, head, set_list) {
+		struct page *page = NULL;
+		struct f2fs_sit_block *raw_sit = NULL;
+		unsigned int start_segno = ses->start_segno;
+		unsigned int end = min(start_segno + SIT_ENTRY_PER_BLOCK,
+						(unsigned long)MAIN_SEGS(sbi));
+		unsigned int segno = start_segno;
+
+		if (to_journal &&
+			!__has_cursum_space(journal, ses->entry_cnt, SIT_JOURNAL))
+			to_journal = false;
+
+		if (to_journal) {
+			down_write(&curseg->journal_rwsem);
+		} else {
+			page = get_next_sit_page(sbi, start_segno);
+			raw_sit = page_address(page);
+		}
+
+		/* flush dirty sit entries in region of current sit set */
+		for_each_set_bit_from(segno, bitmap, end) {
+			int offset, sit_offset;
+
+			se = get_seg_entry(sbi, segno);
+#ifdef CONFIG_F2FS_CHECK_FS
+			if (memcmp(se->cur_valid_map, se->cur_valid_map_mir,
+						SIT_VBLOCK_MAP_SIZE))
+				f2fs_bug_on(sbi, 1);
+#endif
+
+			/* add discard candidates */
+			if (!(cpc->reason & CP_DISCARD)) {
+				cpc->trim_start = segno;
+				add_discard_addrs(sbi, cpc, false);
+			}
+
+			if (to_journal) {
+				offset = f2fs_lookup_journal_in_cursum(journal,
+							SIT_JOURNAL, segno, 1);
+				f2fs_bug_on(sbi, offset < 0);
+				segno_in_journal(journal, offset) =
+							cpu_to_le32(segno);
+				seg_info_to_raw_sit(se,
+					&sit_in_journal(journal, offset));
+				check_block_count(sbi, segno,
+					&sit_in_journal(journal, offset));
+			} else {
+				sit_offset = SIT_ENTRY_OFFSET(sit_i, segno);
+				seg_info_to_raw_sit(se,
+						&raw_sit->entries[sit_offset]);
+				check_block_count(sbi, segno,
+						&raw_sit->entries[sit_offset]);
+			}
+
+			__clear_bit(segno, bitmap);
+			sit_i->dirty_sentries--;
+			ses->entry_cnt--;
+		}
+
+		if (to_journal)
+			up_write(&curseg->journal_rwsem);
+		else
+			f2fs_put_page(page, 1);
+
+		f2fs_bug_on(sbi, ses->entry_cnt);
+		release_sit_entry_set(ses);
+	}
+
+	f2fs_bug_on(sbi, !list_empty(head));
+	f2fs_bug_on(sbi, sit_i->dirty_sentries);
+out:
+	if (cpc->reason & CP_DISCARD) {
+		__u64 trim_start = cpc->trim_start;
+
+		for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
+			add_discard_addrs(sbi, cpc, false);
+
+		cpc->trim_start = trim_start;
+	}
+	up_write(&sit_i->sentry_lock);
+
+	set_prefree_as_free_segments(sbi);
+}
+
+static int build_sit_info(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
+	struct sit_info *sit_i;
+	unsigned int sit_segs, start;
+	char *src_bitmap;
+	unsigned int bitmap_size;
+
+	/* allocate memory for SIT information */
+	sit_i = f2fs_kzalloc(sbi, sizeof(struct sit_info), GFP_KERNEL);
+	if (!sit_i)
+		return -ENOMEM;
+
+	SM_I(sbi)->sit_info = sit_i;
+
+	sit_i->sentries =
+		f2fs_kvzalloc(sbi, array_size(sizeof(struct seg_entry),
+					      MAIN_SEGS(sbi)),
+			      GFP_KERNEL);
+	if (!sit_i->sentries)
+		return -ENOMEM;
+
+	bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi));
+	sit_i->dirty_sentries_bitmap = f2fs_kvzalloc(sbi, bitmap_size,
+								GFP_KERNEL);
+	if (!sit_i->dirty_sentries_bitmap)
+		return -ENOMEM;
+
+	for (start = 0; start < MAIN_SEGS(sbi); start++) {
+		sit_i->sentries[start].cur_valid_map
+			= f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+		sit_i->sentries[start].ckpt_valid_map
+			= f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+		if (!sit_i->sentries[start].cur_valid_map ||
+				!sit_i->sentries[start].ckpt_valid_map)
+			return -ENOMEM;
+
+#ifdef CONFIG_F2FS_CHECK_FS
+		sit_i->sentries[start].cur_valid_map_mir
+			= f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+		if (!sit_i->sentries[start].cur_valid_map_mir)
+			return -ENOMEM;
+#endif
+
+		sit_i->sentries[start].discard_map
+			= f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE,
+							GFP_KERNEL);
+		if (!sit_i->sentries[start].discard_map)
+			return -ENOMEM;
+	}
+
+	sit_i->tmp_map = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+	if (!sit_i->tmp_map)
+		return -ENOMEM;
+
+	if (sbi->segs_per_sec > 1) {
+		sit_i->sec_entries =
+			f2fs_kvzalloc(sbi, array_size(sizeof(struct sec_entry),
+						      MAIN_SECS(sbi)),
+				      GFP_KERNEL);
+		if (!sit_i->sec_entries)
+			return -ENOMEM;
+	}
+
+	/* get information related with SIT */
+	sit_segs = le32_to_cpu(raw_super->segment_count_sit) >> 1;
+
+	/* setup SIT bitmap from ckeckpoint pack */
+	bitmap_size = __bitmap_size(sbi, SIT_BITMAP);
+	src_bitmap = __bitmap_ptr(sbi, SIT_BITMAP);
+
+	sit_i->sit_bitmap = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL);
+	if (!sit_i->sit_bitmap)
+		return -ENOMEM;
+
+#ifdef CONFIG_F2FS_CHECK_FS
+	sit_i->sit_bitmap_mir = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL);
+	if (!sit_i->sit_bitmap_mir)
+		return -ENOMEM;
+#endif
+
+	/* init SIT information */
+	sit_i->s_ops = &default_salloc_ops;
+
+	sit_i->sit_base_addr = le32_to_cpu(raw_super->sit_blkaddr);
+	sit_i->sit_blocks = sit_segs << sbi->log_blocks_per_seg;
+	sit_i->written_valid_blocks = 0;
+	sit_i->bitmap_size = bitmap_size;
+	sit_i->dirty_sentries = 0;
+	sit_i->sents_per_block = SIT_ENTRY_PER_BLOCK;
+	sit_i->elapsed_time = le64_to_cpu(sbi->ckpt->elapsed_time);
+	sit_i->mounted_time = ktime_get_real_seconds();
+	init_rwsem(&sit_i->sentry_lock);
+	return 0;
+}
+
+static int build_free_segmap(struct f2fs_sb_info *sbi)
+{
+	struct free_segmap_info *free_i;
+	unsigned int bitmap_size, sec_bitmap_size;
+
+	/* allocate memory for free segmap information */
+	free_i = f2fs_kzalloc(sbi, sizeof(struct free_segmap_info), GFP_KERNEL);
+	if (!free_i)
+		return -ENOMEM;
+
+	SM_I(sbi)->free_info = free_i;
+
+	bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi));
+	free_i->free_segmap = f2fs_kvmalloc(sbi, bitmap_size, GFP_KERNEL);
+	if (!free_i->free_segmap)
+		return -ENOMEM;
+
+	sec_bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
+	free_i->free_secmap = f2fs_kvmalloc(sbi, sec_bitmap_size, GFP_KERNEL);
+	if (!free_i->free_secmap)
+		return -ENOMEM;
+
+	/* set all segments as dirty temporarily */
+	memset(free_i->free_segmap, 0xff, bitmap_size);
+	memset(free_i->free_secmap, 0xff, sec_bitmap_size);
+
+	/* init free segmap information */
+	free_i->start_segno = GET_SEGNO_FROM_SEG0(sbi, MAIN_BLKADDR(sbi));
+	free_i->free_segments = 0;
+	free_i->free_sections = 0;
+	spin_lock_init(&free_i->segmap_lock);
+	return 0;
+}
+
+static int build_curseg(struct f2fs_sb_info *sbi)
+{
+	struct curseg_info *array;
+	int i;
+
+	array = f2fs_kzalloc(sbi, array_size(NR_CURSEG_TYPE, sizeof(*array)),
+			     GFP_KERNEL);
+	if (!array)
+		return -ENOMEM;
+
+	SM_I(sbi)->curseg_array = array;
+
+	for (i = 0; i < NR_CURSEG_TYPE; i++) {
+		mutex_init(&array[i].curseg_mutex);
+		array[i].sum_blk = f2fs_kzalloc(sbi, PAGE_SIZE, GFP_KERNEL);
+		if (!array[i].sum_blk)
+			return -ENOMEM;
+		init_rwsem(&array[i].journal_rwsem);
+		array[i].journal = f2fs_kzalloc(sbi,
+				sizeof(struct f2fs_journal), GFP_KERNEL);
+		if (!array[i].journal)
+			return -ENOMEM;
+		array[i].segno = NULL_SEGNO;
+		array[i].next_blkoff = 0;
+	}
+	return restore_curseg_summaries(sbi);
+}
+
+static int build_sit_entries(struct f2fs_sb_info *sbi)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA);
+	struct f2fs_journal *journal = curseg->journal;
+	struct seg_entry *se;
+	struct f2fs_sit_entry sit;
+	int sit_blk_cnt = SIT_BLK_CNT(sbi);
+	unsigned int i, start, end;
+	unsigned int readed, start_blk = 0;
+	int err = 0;
+	block_t total_node_blocks = 0;
+
+	do {
+		readed = f2fs_ra_meta_pages(sbi, start_blk, BIO_MAX_PAGES,
+							META_SIT, true);
+
+		start = start_blk * sit_i->sents_per_block;
+		end = (start_blk + readed) * sit_i->sents_per_block;
+
+		for (; start < end && start < MAIN_SEGS(sbi); start++) {
+			struct f2fs_sit_block *sit_blk;
+			struct page *page;
+
+			se = &sit_i->sentries[start];
+			page = get_current_sit_page(sbi, start);
+			sit_blk = (struct f2fs_sit_block *)page_address(page);
+			sit = sit_blk->entries[SIT_ENTRY_OFFSET(sit_i, start)];
+			f2fs_put_page(page, 1);
+
+			err = check_block_count(sbi, start, &sit);
+			if (err)
+				return err;
+			seg_info_from_raw_sit(se, &sit);
+			if (IS_NODESEG(se->type))
+				total_node_blocks += se->valid_blocks;
+
+			/* build discard map only one time */
+			if (is_set_ckpt_flags(sbi, CP_TRIMMED_FLAG)) {
+				memset(se->discard_map, 0xff,
+					SIT_VBLOCK_MAP_SIZE);
+			} else {
+				memcpy(se->discard_map,
+					se->cur_valid_map,
+					SIT_VBLOCK_MAP_SIZE);
+				sbi->discard_blks +=
+					sbi->blocks_per_seg -
+					se->valid_blocks;
+			}
+
+			if (sbi->segs_per_sec > 1)
+				get_sec_entry(sbi, start)->valid_blocks +=
+							se->valid_blocks;
+		}
+		start_blk += readed;
+	} while (start_blk < sit_blk_cnt);
+
+	down_read(&curseg->journal_rwsem);
+	for (i = 0; i < sits_in_cursum(journal); i++) {
+		unsigned int old_valid_blocks;
+
+		start = le32_to_cpu(segno_in_journal(journal, i));
+		if (start >= MAIN_SEGS(sbi)) {
+			f2fs_msg(sbi->sb, KERN_ERR,
+					"Wrong journal entry on segno %u",
+					start);
+			set_sbi_flag(sbi, SBI_NEED_FSCK);
+			err = -EFSCORRUPTED;
+			break;
+		}
+
+		se = &sit_i->sentries[start];
+		sit = sit_in_journal(journal, i);
+
+		old_valid_blocks = se->valid_blocks;
+		if (IS_NODESEG(se->type))
+			total_node_blocks -= old_valid_blocks;
+
+		err = check_block_count(sbi, start, &sit);
+		if (err)
+			break;
+		seg_info_from_raw_sit(se, &sit);
+		if (IS_NODESEG(se->type))
+			total_node_blocks += se->valid_blocks;
+
+		if (is_set_ckpt_flags(sbi, CP_TRIMMED_FLAG)) {
+			memset(se->discard_map, 0xff, SIT_VBLOCK_MAP_SIZE);
+		} else {
+			memcpy(se->discard_map, se->cur_valid_map,
+						SIT_VBLOCK_MAP_SIZE);
+			sbi->discard_blks += old_valid_blocks;
+			sbi->discard_blks -= se->valid_blocks;
+		}
+
+		if (sbi->segs_per_sec > 1) {
+			get_sec_entry(sbi, start)->valid_blocks +=
+							se->valid_blocks;
+			get_sec_entry(sbi, start)->valid_blocks -=
+							old_valid_blocks;
+		}
+	}
+	up_read(&curseg->journal_rwsem);
+
+	if (!err && total_node_blocks != valid_node_count(sbi)) {
+		f2fs_msg(sbi->sb, KERN_ERR,
+			"SIT is corrupted node# %u vs %u",
+			total_node_blocks, valid_node_count(sbi));
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		err = -EFSCORRUPTED;
+	}
+
+	return err;
+}
+
+static void init_free_segmap(struct f2fs_sb_info *sbi)
+{
+	unsigned int start;
+	int type;
+
+	for (start = 0; start < MAIN_SEGS(sbi); start++) {
+		struct seg_entry *sentry = get_seg_entry(sbi, start);
+		if (!sentry->valid_blocks)
+			__set_free(sbi, start);
+		else
+			SIT_I(sbi)->written_valid_blocks +=
+						sentry->valid_blocks;
+	}
+
+	/* set use the current segments */
+	for (type = CURSEG_HOT_DATA; type <= CURSEG_COLD_NODE; type++) {
+		struct curseg_info *curseg_t = CURSEG_I(sbi, type);
+		__set_test_and_inuse(sbi, curseg_t->segno);
+	}
+}
+
+static void init_dirty_segmap(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	struct free_segmap_info *free_i = FREE_I(sbi);
+	unsigned int segno = 0, offset = 0;
+	unsigned short valid_blocks;
+
+	while (1) {
+		/* find dirty segment based on free segmap */
+		segno = find_next_inuse(free_i, MAIN_SEGS(sbi), offset);
+		if (segno >= MAIN_SEGS(sbi))
+			break;
+		offset = segno + 1;
+		valid_blocks = get_valid_blocks(sbi, segno, false);
+		if (valid_blocks == sbi->blocks_per_seg || !valid_blocks)
+			continue;
+		if (valid_blocks > sbi->blocks_per_seg) {
+			f2fs_bug_on(sbi, 1);
+			continue;
+		}
+		mutex_lock(&dirty_i->seglist_lock);
+		__locate_dirty_segment(sbi, segno, DIRTY);
+		mutex_unlock(&dirty_i->seglist_lock);
+	}
+}
+
+static int init_victim_secmap(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	unsigned int bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
+
+	dirty_i->victim_secmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
+	if (!dirty_i->victim_secmap)
+		return -ENOMEM;
+	return 0;
+}
+
+static int build_dirty_segmap(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i;
+	unsigned int bitmap_size, i;
+
+	/* allocate memory for dirty segments list information */
+	dirty_i = f2fs_kzalloc(sbi, sizeof(struct dirty_seglist_info),
+								GFP_KERNEL);
+	if (!dirty_i)
+		return -ENOMEM;
+
+	SM_I(sbi)->dirty_info = dirty_i;
+	mutex_init(&dirty_i->seglist_lock);
+
+	bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi));
+
+	for (i = 0; i < NR_DIRTY_TYPE; i++) {
+		dirty_i->dirty_segmap[i] = f2fs_kvzalloc(sbi, bitmap_size,
+								GFP_KERNEL);
+		if (!dirty_i->dirty_segmap[i])
+			return -ENOMEM;
+	}
+
+	init_dirty_segmap(sbi);
+	return init_victim_secmap(sbi);
+}
+
+static int sanity_check_curseg(struct f2fs_sb_info *sbi)
+{
+	int i;
+
+	/*
+	 * In LFS/SSR curseg, .next_blkoff should point to an unused blkaddr;
+	 * In LFS curseg, all blkaddr after .next_blkoff should be unused.
+	 */
+	for (i = 0; i < NO_CHECK_TYPE; i++) {
+		struct curseg_info *curseg = CURSEG_I(sbi, i);
+		struct seg_entry *se = get_seg_entry(sbi, curseg->segno);
+		unsigned int blkofs = curseg->next_blkoff;
+
+		if (f2fs_test_bit(blkofs, se->cur_valid_map))
+			goto out;
+
+		if (curseg->alloc_type == SSR)
+			continue;
+
+		for (blkofs += 1; blkofs < sbi->blocks_per_seg; blkofs++) {
+			if (!f2fs_test_bit(blkofs, se->cur_valid_map))
+				continue;
+out:
+			f2fs_msg(sbi->sb, KERN_ERR,
+				"Current segment's next free block offset is "
+				"inconsistent with bitmap, logtype:%u, "
+				"segno:%u, type:%u, next_blkoff:%u, blkofs:%u",
+				i, curseg->segno, curseg->alloc_type,
+				curseg->next_blkoff, blkofs);
+			return -EFSCORRUPTED;
+		}
+	}
+	return 0;
+}
+
+/*
+ * Update min, max modified time for cost-benefit GC algorithm
+ */
+static void init_min_max_mtime(struct f2fs_sb_info *sbi)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int segno;
+
+	down_write(&sit_i->sentry_lock);
+
+	sit_i->min_mtime = ULLONG_MAX;
+
+	for (segno = 0; segno < MAIN_SEGS(sbi); segno += sbi->segs_per_sec) {
+		unsigned int i;
+		unsigned long long mtime = 0;
+
+		for (i = 0; i < sbi->segs_per_sec; i++)
+			mtime += get_seg_entry(sbi, segno + i)->mtime;
+
+		mtime = div_u64(mtime, sbi->segs_per_sec);
+
+		if (sit_i->min_mtime > mtime)
+			sit_i->min_mtime = mtime;
+	}
+	sit_i->max_mtime = get_mtime(sbi, false);
+	up_write(&sit_i->sentry_lock);
+}
+
+int f2fs_build_segment_manager(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
+	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
+	struct f2fs_sm_info *sm_info;
+	int err;
+
+	sm_info = f2fs_kzalloc(sbi, sizeof(struct f2fs_sm_info), GFP_KERNEL);
+	if (!sm_info)
+		return -ENOMEM;
+
+	/* init sm info */
+	sbi->sm_info = sm_info;
+	sm_info->seg0_blkaddr = le32_to_cpu(raw_super->segment0_blkaddr);
+	sm_info->main_blkaddr = le32_to_cpu(raw_super->main_blkaddr);
+	sm_info->segment_count = le32_to_cpu(raw_super->segment_count);
+	sm_info->reserved_segments = le32_to_cpu(ckpt->rsvd_segment_count);
+	sm_info->ovp_segments = le32_to_cpu(ckpt->overprov_segment_count);
+	sm_info->main_segments = le32_to_cpu(raw_super->segment_count_main);
+	sm_info->ssa_blkaddr = le32_to_cpu(raw_super->ssa_blkaddr);
+	sm_info->rec_prefree_segments = sm_info->main_segments *
+					DEF_RECLAIM_PREFREE_SEGMENTS / 100;
+	if (sm_info->rec_prefree_segments > DEF_MAX_RECLAIM_PREFREE_SEGMENTS)
+		sm_info->rec_prefree_segments = DEF_MAX_RECLAIM_PREFREE_SEGMENTS;
+
+	if (!test_opt(sbi, LFS))
+		sm_info->ipu_policy = 1 << F2FS_IPU_FSYNC;
+	sm_info->min_ipu_util = DEF_MIN_IPU_UTIL;
+	sm_info->min_fsync_blocks = DEF_MIN_FSYNC_BLOCKS;
+	sm_info->min_seq_blocks = sbi->blocks_per_seg * sbi->segs_per_sec;
+	sm_info->min_hot_blocks = DEF_MIN_HOT_BLOCKS;
+	sm_info->min_ssr_sections = reserved_sections(sbi);
+
+	INIT_LIST_HEAD(&sm_info->sit_entry_set);
+
+	init_rwsem(&sm_info->curseg_lock);
+
+	if (!f2fs_readonly(sbi->sb)) {
+		err = f2fs_create_flush_cmd_control(sbi);
+		if (err)
+			return err;
+	}
+
+	err = create_discard_cmd_control(sbi);
+	if (err)
+		return err;
+
+	err = build_sit_info(sbi);
+	if (err)
+		return err;
+	err = build_free_segmap(sbi);
+	if (err)
+		return err;
+	err = build_curseg(sbi);
+	if (err)
+		return err;
+
+	/* reinit free segmap based on SIT */
+	err = build_sit_entries(sbi);
+	if (err)
+		return err;
+
+	init_free_segmap(sbi);
+	err = build_dirty_segmap(sbi);
+	if (err)
+		return err;
+
+	err = sanity_check_curseg(sbi);
+	if (err)
+		return err;
+
+	init_min_max_mtime(sbi);
+	return 0;
+}
+
+static void discard_dirty_segmap(struct f2fs_sb_info *sbi,
+		enum dirty_type dirty_type)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+
+	mutex_lock(&dirty_i->seglist_lock);
+	kvfree(dirty_i->dirty_segmap[dirty_type]);
+	dirty_i->nr_dirty[dirty_type] = 0;
+	mutex_unlock(&dirty_i->seglist_lock);
+}
+
+static void destroy_victim_secmap(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	kvfree(dirty_i->victim_secmap);
+}
+
+static void destroy_dirty_segmap(struct f2fs_sb_info *sbi)
+{
+	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+	int i;
+
+	if (!dirty_i)
+		return;
+
+	/* discard pre-free/dirty segments list */
+	for (i = 0; i < NR_DIRTY_TYPE; i++)
+		discard_dirty_segmap(sbi, i);
+
+	destroy_victim_secmap(sbi);
+	SM_I(sbi)->dirty_info = NULL;
+	kfree(dirty_i);
+}
+
+static void destroy_curseg(struct f2fs_sb_info *sbi)
+{
+	struct curseg_info *array = SM_I(sbi)->curseg_array;
+	int i;
+
+	if (!array)
+		return;
+	SM_I(sbi)->curseg_array = NULL;
+	for (i = 0; i < NR_CURSEG_TYPE; i++) {
+		kfree(array[i].sum_blk);
+		kfree(array[i].journal);
+	}
+	kfree(array);
+}
+
+static void destroy_free_segmap(struct f2fs_sb_info *sbi)
+{
+	struct free_segmap_info *free_i = SM_I(sbi)->free_info;
+	if (!free_i)
+		return;
+	SM_I(sbi)->free_info = NULL;
+	kvfree(free_i->free_segmap);
+	kvfree(free_i->free_secmap);
+	kfree(free_i);
+}
+
+static void destroy_sit_info(struct f2fs_sb_info *sbi)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int start;
+
+	if (!sit_i)
+		return;
+
+	if (sit_i->sentries) {
+		for (start = 0; start < MAIN_SEGS(sbi); start++) {
+			kfree(sit_i->sentries[start].cur_valid_map);
+#ifdef CONFIG_F2FS_CHECK_FS
+			kfree(sit_i->sentries[start].cur_valid_map_mir);
+#endif
+			kfree(sit_i->sentries[start].ckpt_valid_map);
+			kfree(sit_i->sentries[start].discard_map);
+		}
+	}
+	kfree(sit_i->tmp_map);
+
+	kvfree(sit_i->sentries);
+	kvfree(sit_i->sec_entries);
+	kvfree(sit_i->dirty_sentries_bitmap);
+
+	SM_I(sbi)->sit_info = NULL;
+	kfree(sit_i->sit_bitmap);
+#ifdef CONFIG_F2FS_CHECK_FS
+	kfree(sit_i->sit_bitmap_mir);
+#endif
+	kfree(sit_i);
+}
+
+void f2fs_destroy_segment_manager(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_sm_info *sm_info = SM_I(sbi);
+
+	if (!sm_info)
+		return;
+	f2fs_destroy_flush_cmd_control(sbi, true);
+	destroy_discard_cmd_control(sbi);
+	destroy_dirty_segmap(sbi);
+	destroy_curseg(sbi);
+	destroy_free_segmap(sbi);
+	destroy_sit_info(sbi);
+	sbi->sm_info = NULL;
+	kfree(sm_info);
+}
+
+int __init f2fs_create_segment_manager_caches(void)
+{
+	discard_entry_slab = f2fs_kmem_cache_create("discard_entry",
+			sizeof(struct discard_entry));
+	if (!discard_entry_slab)
+		goto fail;
+
+	discard_cmd_slab = f2fs_kmem_cache_create("discard_cmd",
+			sizeof(struct discard_cmd));
+	if (!discard_cmd_slab)
+		goto destroy_discard_entry;
+
+	sit_entry_set_slab = f2fs_kmem_cache_create("sit_entry_set",
+			sizeof(struct sit_entry_set));
+	if (!sit_entry_set_slab)
+		goto destroy_discard_cmd;
+
+	inmem_entry_slab = f2fs_kmem_cache_create("inmem_page_entry",
+			sizeof(struct inmem_pages));
+	if (!inmem_entry_slab)
+		goto destroy_sit_entry_set;
+	return 0;
+
+destroy_sit_entry_set:
+	kmem_cache_destroy(sit_entry_set_slab);
+destroy_discard_cmd:
+	kmem_cache_destroy(discard_cmd_slab);
+destroy_discard_entry:
+	kmem_cache_destroy(discard_entry_slab);
+fail:
+	return -ENOMEM;
+}
+
+void f2fs_destroy_segment_manager_caches(void)
+{
+	kmem_cache_destroy(sit_entry_set_slab);
+	kmem_cache_destroy(discard_cmd_slab);
+	kmem_cache_destroy(discard_entry_slab);
+	kmem_cache_destroy(inmem_entry_slab);
+}