Initial import

1 files changed, 2307 insertions, 0 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
new file mode 100644
index 000000000..f93966094
--- /dev/null
+++ b/fs/f2fs/segment.c
@@ -0,0 +1,2307 @@
+/*
+ * 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/vmalloc.h>
+#include <linux/swap.h>
+
+#include "f2fs.h"
+#include "segment.h"
+#include "node.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 *sit_entry_set_slab;
+static struct kmem_cache *inmem_entry_slab;
+
+/*
+ * __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 & 0xffffffff) == 0) {
+		num += 32;
+		word >>= 32;
+	}
+#endif
+	if ((word & 0xffff) == 0) {
+		num += 16;
+		word >>= 16;
+	}
+	if ((word & 0xff) == 0) {
+		num += 8;
+		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.
+ * Example:
+ *                             LSB <--> MSB
+ *   f2fs_set_bit(0, bitmap) => 0000 0001
+ *   f2fs_set_bit(7, bitmap) => 1000 0000
+ */
+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 = offset & ~(BITS_PER_LONG - 1);
+	unsigned long tmp;
+	unsigned long mask, submask;
+	unsigned long quot, rest;
+
+	if (offset >= size)
+		return size;
+
+	size -= result;
+	offset %= BITS_PER_LONG;
+	if (!offset)
+		goto aligned;
+
+	tmp = *(p++);
+	quot = (offset >> 3) << 3;
+	rest = offset & 0x7;
+	mask = ~0UL << quot;
+	submask = (unsigned char)(0xff << rest) >> rest;
+	submask <<= quot;
+	mask &= submask;
+	tmp &= mask;
+	if (size < BITS_PER_LONG)
+		goto found_first;
+	if (tmp)
+		goto found_middle;
+
+	size -= BITS_PER_LONG;
+	result += BITS_PER_LONG;
+aligned:
+	while (size & ~(BITS_PER_LONG-1)) {
+		tmp = *(p++);
+		if (tmp)
+			goto found_middle;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+found_first:
+	tmp &= (~0UL >> (BITS_PER_LONG - size));
+	if (tmp == 0UL)		/* Are any bits set? */
+		return result + size;   /* Nope. */
+found_middle:
+	return result + __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 = offset & ~(BITS_PER_LONG - 1);
+	unsigned long tmp;
+	unsigned long mask, submask;
+	unsigned long quot, rest;
+
+	if (offset >= size)
+		return size;
+
+	size -= result;
+	offset %= BITS_PER_LONG;
+	if (!offset)
+		goto aligned;
+
+	tmp = *(p++);
+	quot = (offset >> 3) << 3;
+	rest = offset & 0x7;
+	mask = ~(~0UL << quot);
+	submask = (unsigned char)~((unsigned char)(0xff << rest) >> rest);
+	submask <<= quot;
+	mask += submask;
+	tmp |= mask;
+	if (size < BITS_PER_LONG)
+		goto found_first;
+	if (~tmp)
+		goto found_middle;
+
+	size -= BITS_PER_LONG;
+	result += BITS_PER_LONG;
+aligned:
+	while (size & ~(BITS_PER_LONG - 1)) {
+		tmp = *(p++);
+		if (~tmp)
+			goto found_middle;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+
+found_first:
+	tmp |= ~0UL << size;
+	if (tmp == ~0UL)        /* Are any bits zero? */
+		return result + size;   /* Nope. */
+found_middle:
+	return result + __reverse_ffz(tmp);
+}
+
+void register_inmem_page(struct inode *inode, struct page *page)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct inmem_pages *new;
+	int err;
+
+	SetPagePrivate(page);
+	f2fs_trace_pid(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);
+retry:
+	/* increase reference count with clean state */
+	mutex_lock(&fi->inmem_lock);
+	err = radix_tree_insert(&fi->inmem_root, page->index, new);
+	if (err == -EEXIST) {
+		mutex_unlock(&fi->inmem_lock);
+		kmem_cache_free(inmem_entry_slab, new);
+		return;
+	} else if (err) {
+		mutex_unlock(&fi->inmem_lock);
+		goto retry;
+	}
+	get_page(page);
+	list_add_tail(&new->list, &fi->inmem_pages);
+	inc_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
+	mutex_unlock(&fi->inmem_lock);
+
+	trace_f2fs_register_inmem_page(page, INMEM);
+}
+
+void commit_inmem_pages(struct inode *inode, bool abort)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct inmem_pages *cur, *tmp;
+	bool submit_bio = false;
+	struct f2fs_io_info fio = {
+		.type = DATA,
+		.rw = WRITE_SYNC | REQ_PRIO,
+	};
+
+	/*
+	 * The abort is true only when f2fs_evict_inode is called.
+	 * Basically, the f2fs_evict_inode doesn't produce any data writes, so
+	 * that we don't need to call f2fs_balance_fs.
+	 * Otherwise, f2fs_gc in f2fs_balance_fs can wait forever until this
+	 * inode becomes free by iget_locked in f2fs_iget.
+	 */
+	if (!abort) {
+		f2fs_balance_fs(sbi);
+		f2fs_lock_op(sbi);
+	}
+
+	mutex_lock(&fi->inmem_lock);
+	list_for_each_entry_safe(cur, tmp, &fi->inmem_pages, list) {
+		if (!abort) {
+			lock_page(cur->page);
+			if (cur->page->mapping == inode->i_mapping) {
+				f2fs_wait_on_page_writeback(cur->page, DATA);
+				if (clear_page_dirty_for_io(cur->page))
+					inode_dec_dirty_pages(inode);
+				trace_f2fs_commit_inmem_page(cur->page, INMEM);
+				do_write_data_page(cur->page, &fio);
+				submit_bio = true;
+			}
+			f2fs_put_page(cur->page, 1);
+		} else {
+			trace_f2fs_commit_inmem_page(cur->page, INMEM_DROP);
+			put_page(cur->page);
+		}
+		radix_tree_delete(&fi->inmem_root, cur->page->index);
+		list_del(&cur->list);
+		kmem_cache_free(inmem_entry_slab, cur);
+		dec_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
+	}
+	mutex_unlock(&fi->inmem_lock);
+
+	if (!abort) {
+		f2fs_unlock_op(sbi);
+		if (submit_bio)
+			f2fs_submit_merged_bio(sbi, DATA, WRITE);
+	}
+}
+
+/*
+ * This function balances dirty node and dentry pages.
+ * In addition, it controls garbage collection.
+ */
+void f2fs_balance_fs(struct f2fs_sb_info *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)) {
+		mutex_lock(&sbi->gc_mutex);
+		f2fs_gc(sbi);
+	}
+}
+
+void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
+{
+	/* try to shrink extent cache when there is no enough memory */
+	f2fs_shrink_extent_tree(sbi, EXTENT_CACHE_SHRINK_NUMBER);
+
+	/* check the # of cached NAT entries and prefree segments */
+	if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK) ||
+			excess_prefree_segs(sbi) ||
+			!available_free_memory(sbi, INO_ENTRIES))
+		f2fs_sync_fs(sbi->sb, true);
+}
+
+static int issue_flush_thread(void *data)
+{
+	struct f2fs_sb_info *sbi = data;
+	struct flush_cmd_control *fcc = SM_I(sbi)->cmd_control_info;
+	wait_queue_head_t *q = &fcc->flush_wait_queue;
+repeat:
+	if (kthread_should_stop())
+		return 0;
+
+	if (!llist_empty(&fcc->issue_list)) {
+		struct bio *bio = bio_alloc(GFP_NOIO, 0);
+		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);
+
+		bio->bi_bdev = sbi->sb->s_bdev;
+		ret = submit_bio_wait(WRITE_FLUSH, bio);
+
+		llist_for_each_entry_safe(cmd, next,
+					  fcc->dispatch_list, llnode) {
+			cmd->ret = ret;
+			complete(&cmd->wait);
+		}
+		bio_put(bio);
+		fcc->dispatch_list = NULL;
+	}
+
+	wait_event_interruptible(*q,
+		kthread_should_stop() || !llist_empty(&fcc->issue_list));
+	goto repeat;
+}
+
+int f2fs_issue_flush(struct f2fs_sb_info *sbi)
+{
+	struct flush_cmd_control *fcc = SM_I(sbi)->cmd_control_info;
+	struct flush_cmd cmd;
+
+	trace_f2fs_issue_flush(sbi->sb, test_opt(sbi, NOBARRIER),
+					test_opt(sbi, FLUSH_MERGE));
+
+	if (test_opt(sbi, NOBARRIER))
+		return 0;
+
+	if (!test_opt(sbi, FLUSH_MERGE))
+		return blkdev_issue_flush(sbi->sb->s_bdev, GFP_KERNEL, NULL);
+
+	init_completion(&cmd.wait);
+
+	llist_add(&cmd.llnode, &fcc->issue_list);
+
+	if (!fcc->dispatch_list)
+		wake_up(&fcc->flush_wait_queue);
+
+	wait_for_completion(&cmd.wait);
+
+	return cmd.ret;
+}
+
+int 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;
+
+	fcc = kzalloc(sizeof(struct flush_cmd_control), GFP_KERNEL);
+	if (!fcc)
+		return -ENOMEM;
+	init_waitqueue_head(&fcc->flush_wait_queue);
+	init_llist_head(&fcc->issue_list);
+	SM_I(sbi)->cmd_control_info = fcc;
+	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)->cmd_control_info = NULL;
+		return err;
+	}
+
+	return err;
+}
+
+void destroy_flush_cmd_control(struct f2fs_sb_info *sbi)
+{
+	struct flush_cmd_control *fcc = SM_I(sbi)->cmd_control_info;
+
+	if (fcc && fcc->f2fs_issue_flush)
+		kthread_stop(fcc->f2fs_issue_flush);
+	kfree(fcc);
+	SM_I(sbi)->cmd_control_info = NULL;
+}
+
+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, sbi->segs_per_sec) == 0)
+			clear_bit(GET_SECNO(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, 0);
+
+	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 int f2fs_issue_discard(struct f2fs_sb_info *sbi,
+				block_t blkstart, block_t blklen)
+{
+	sector_t start = SECTOR_FROM_BLOCK(blkstart);
+	sector_t len = SECTOR_FROM_BLOCK(blklen);
+	trace_f2fs_issue_discard(sbi->sb, blkstart, blklen);
+	return blkdev_issue_discard(sbi->sb->s_bdev, start, len, GFP_NOFS, 0);
+}
+
+void discard_next_dnode(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	if (f2fs_issue_discard(sbi, blkaddr, 1)) {
+		struct page *page = grab_meta_page(sbi, blkaddr);
+		/* zero-filled page */
+		set_page_dirty(page);
+		f2fs_put_page(page, 1);
+	}
+}
+
+static void __add_discard_entry(struct f2fs_sb_info *sbi,
+		struct cp_control *cpc, unsigned int start, unsigned int end)
+{
+	struct list_head *head = &SM_I(sbi)->discard_list;
+	struct discard_entry *new, *last;
+
+	if (!list_empty(head)) {
+		last = list_last_entry(head, struct discard_entry, list);
+		if (START_BLOCK(sbi, cpc->trim_start) + start ==
+						last->blkaddr + last->len) {
+			last->len += end - start;
+			goto done;
+		}
+	}
+
+	new = f2fs_kmem_cache_alloc(discard_entry_slab, GFP_NOFS);
+	INIT_LIST_HEAD(&new->list);
+	new->blkaddr = START_BLOCK(sbi, cpc->trim_start) + start;
+	new->len = end - start;
+	list_add_tail(&new->list, head);
+done:
+	SM_I(sbi)->nr_discards += end - start;
+	cpc->trimmed += end - start;
+}
+
+static void add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc)
+{
+	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 *dmap = SIT_I(sbi)->tmp_map;
+	unsigned int start = 0, end = -1;
+	bool force = (cpc->reason == CP_DISCARD);
+	int i;
+
+	if (!force && (!test_opt(sbi, DISCARD) ||
+			SM_I(sbi)->nr_discards >= SM_I(sbi)->max_discards))
+		return;
+
+	if (force && !se->valid_blocks) {
+		struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
+		/*
+		 * if this segment is registered in the prefree list, then
+		 * we should skip adding a discard candidate, and let the
+		 * checkpoint do that later.
+		 */
+		mutex_lock(&dirty_i->seglist_lock);
+		if (test_bit(cpc->trim_start, dirty_i->dirty_segmap[PRE])) {
+			mutex_unlock(&dirty_i->seglist_lock);
+			cpc->trimmed += sbi->blocks_per_seg;
+			return;
+		}
+		mutex_unlock(&dirty_i->seglist_lock);
+
+		__add_discard_entry(sbi, cpc, 0, sbi->blocks_per_seg);
+		return;
+	}
+
+	/* zero block will be discarded through the prefree list */
+	if (!se->valid_blocks || se->valid_blocks == max_blocks)
+		return;
+
+	/* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
+	for (i = 0; i < entries; i++)
+		dmap[i] = force ? ~ckpt_map[i] :
+				(cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
+
+	while (force || SM_I(sbi)->nr_discards <= SM_I(sbi)->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 && end - start < cpc->trim_minlen)
+			continue;
+
+		__add_discard_entry(sbi, cpc, start, end);
+	}
+}
+
+void release_discard_addrs(struct f2fs_sb_info *sbi)
+{
+	struct list_head *head = &(SM_I(sbi)->discard_list);
+	struct discard_entry *entry, *this;
+
+	/* drop caches */
+	list_for_each_entry_safe(entry, this, head, list) {
+		list_del(&entry->list);
+		kmem_cache_free(discard_entry_slab, entry);
+	}
+}
+
+/*
+ * Should call 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 clear_prefree_segments(struct f2fs_sb_info *sbi)
+{
+	struct list_head *head = &(SM_I(sbi)->discard_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;
+
+	mutex_lock(&dirty_i->seglist_lock);
+
+	while (1) {
+		int i;
+		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);
+
+		for (i = start; i < end; i++)
+			clear_bit(i, prefree_map);
+
+		dirty_i->nr_dirty[PRE] -= end - start;
+
+		if (!test_opt(sbi, DISCARD))
+			continue;
+
+		f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
+				(end - start) << sbi->log_blocks_per_seg);
+	}
+	mutex_unlock(&dirty_i->seglist_lock);
+
+	/* send small discards */
+	list_for_each_entry_safe(entry, this, head, list) {
+		f2fs_issue_discard(sbi, entry->blkaddr, entry->len);
+		list_del(&entry->list);
+		SM_I(sbi)->nr_discards -= entry->len;
+		kmem_cache_free(discard_entry_slab, entry);
+	}
+}
+
+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;
+
+	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);
+	SIT_I(sbi)->max_mtime = se->mtime;
+
+	/* Update valid block bitmap */
+	if (del > 0) {
+		if (f2fs_test_and_set_bit(offset, se->cur_valid_map))
+			f2fs_bug_on(sbi, 1);
+	} else {
+		if (!f2fs_test_and_clear_bit(offset, se->cur_valid_map))
+			f2fs_bug_on(sbi, 1);
+	}
+	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 refresh_sit_entry(struct f2fs_sb_info *sbi, block_t old, block_t new)
+{
+	update_sit_entry(sbi, new, 1);
+	if (GET_SEGNO(sbi, old) != NULL_SEGNO)
+		update_sit_entry(sbi, old, -1);
+
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, old));
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, new));
+}
+
+void 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;
+
+	/* add it into sit main buffer */
+	mutex_lock(&sit_i->sentry_lock);
+
+	update_sit_entry(sbi, addr, -1);
+
+	/* add it into dirty seglist */
+	locate_dirty_segment(sbi, segno);
+
+	mutex_unlock(&sit_i->sentry_lock);
+}
+
+/*
+ * 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 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_CACHE_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_CACHE_SIZE - SUM_FOOTER_SIZE) / SUMMARY_SIZE)
+		return 2;
+	return 3;
+}
+
+/*
+ * Caller should put this summary page
+ */
+struct page *get_sum_page(struct f2fs_sb_info *sbi, unsigned int segno)
+{
+	return get_meta_page(sbi, GET_SUM_BLOCK(sbi, segno));
+}
+
+static void write_sum_page(struct f2fs_sb_info *sbi,
+			struct f2fs_summary_block *sum_blk, block_t blk_addr)
+{
+	struct page *page = grab_meta_page(sbi, blk_addr);
+	void *kaddr = page_address(page);
+	memcpy(kaddr, sum_blk, PAGE_CACHE_SIZE);
+	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 = *newseg / sbi->segs_per_sec;
+	unsigned int old_zoneno = GET_ZONENO_FROM_SEGNO(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,
+					MAIN_SEGS(sbi), *newseg + 1);
+		if (segno - *newseg < sbi->segs_per_sec -
+					(*newseg % sbi->segs_per_sec))
+			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:
+	hint = secno;
+	segno = secno * sbi->segs_per_sec;
+	zoneno = secno / sbi->secs_per_zone;
+
+	/* 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_ZONENO_FROM_SEGNO(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);
+}
+
+/*
+ * 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;
+
+	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, bool reuse)
+{
+	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);
+
+	if (reuse) {
+		sum_page = 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;
+
+	if (IS_NODESEG(type) || !has_not_enough_free_secs(sbi, 0))
+		return v_ops->get_victim(sbi,
+				&(curseg)->next_segno, BG_GC, type, SSR);
+
+	/* For data segments, let's do SSR more intensively */
+	for (; type >= CURSEG_HOT_DATA; type--)
+		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
+						BG_GC, type, SSR))
+			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 (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 (need_SSR(sbi) && get_ssr_segment(sbi, type))
+		change_curseg(sbi, type, true);
+	else
+		new_curseg(sbi, type, false);
+
+	stat_inc_seg_type(sbi, curseg);
+}
+
+static void __allocate_new_segments(struct f2fs_sb_info *sbi, int type)
+{
+	struct curseg_info *curseg = CURSEG_I(sbi, type);
+	unsigned int old_segno;
+
+	old_segno = curseg->segno;
+	SIT_I(sbi)->s_ops->allocate_segment(sbi, type, true);
+	locate_dirty_segment(sbi, old_segno);
+}
+
+void allocate_new_segments(struct f2fs_sb_info *sbi)
+{
+	int i;
+
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++)
+		__allocate_new_segments(sbi, i);
+}
+
+static const struct segment_allocation default_salloc_ops = {
+	.allocate_segment = allocate_segment_by_default,
+};
+
+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;
+	struct cp_control cpc;
+
+	if (range->minlen > SEGMENT_SIZE(sbi) || start >= MAX_BLKADDR(sbi) ||
+						range->len < sbi->blocksize)
+		return -EINVAL;
+
+	cpc.trimmed = 0;
+	if (end <= MAIN_BLKADDR(sbi))
+		goto out;
+
+	/* 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);
+	cpc.reason = CP_DISCARD;
+	cpc.trim_minlen = F2FS_BYTES_TO_BLK(range->minlen);
+
+	/* do checkpoint to issue discard commands safely */
+	for (; start_segno <= end_segno; start_segno = cpc.trim_end + 1) {
+		cpc.trim_start = start_segno;
+		cpc.trim_end = min_t(unsigned int, rounddown(start_segno +
+				BATCHED_TRIM_SEGMENTS(sbi),
+				sbi->segs_per_sec) - 1, end_segno);
+
+		mutex_lock(&sbi->gc_mutex);
+		write_checkpoint(sbi, &cpc);
+		mutex_unlock(&sbi->gc_mutex);
+	}
+out:
+	range->len = F2FS_BLK_TO_BYTES(cpc.trimmed);
+	return 0;
+}
+
+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;
+}
+
+static int __get_segment_type_2(struct page *page, enum page_type p_type)
+{
+	if (p_type == DATA)
+		return CURSEG_HOT_DATA;
+	else
+		return CURSEG_HOT_NODE;
+}
+
+static int __get_segment_type_4(struct page *page, enum page_type p_type)
+{
+	if (p_type == DATA) {
+		struct inode *inode = page->mapping->host;
+
+		if (S_ISDIR(inode->i_mode))
+			return CURSEG_HOT_DATA;
+		else
+			return CURSEG_COLD_DATA;
+	} else {
+		if (IS_DNODE(page) && is_cold_node(page))
+			return CURSEG_WARM_NODE;
+		else
+			return CURSEG_COLD_NODE;
+	}
+}
+
+static int __get_segment_type_6(struct page *page, enum page_type p_type)
+{
+	if (p_type == DATA) {
+		struct inode *inode = page->mapping->host;
+
+		if (S_ISDIR(inode->i_mode))
+			return CURSEG_HOT_DATA;
+		else if (is_cold_data(page) || file_is_cold(inode))
+			return CURSEG_COLD_DATA;
+		else
+			return CURSEG_WARM_DATA;
+	} else {
+		if (IS_DNODE(page))
+			return is_cold_node(page) ? CURSEG_WARM_NODE :
+						CURSEG_HOT_NODE;
+		else
+			return CURSEG_COLD_NODE;
+	}
+}
+
+static int __get_segment_type(struct page *page, enum page_type p_type)
+{
+	switch (F2FS_P_SB(page)->active_logs) {
+	case 2:
+		return __get_segment_type_2(page, p_type);
+	case 4:
+		return __get_segment_type_4(page, p_type);
+	}
+	/* NR_CURSEG_TYPE(6) logs by default */
+	f2fs_bug_on(F2FS_P_SB(page),
+		F2FS_P_SB(page)->active_logs != NR_CURSEG_TYPE);
+	return __get_segment_type_6(page, p_type);
+}
+
+void 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 sit_info *sit_i = SIT_I(sbi);
+	struct curseg_info *curseg;
+	bool direct_io = (type == CURSEG_DIRECT_IO);
+
+	type = direct_io ? CURSEG_WARM_DATA : type;
+
+	curseg = CURSEG_I(sbi, type);
+
+	mutex_lock(&curseg->curseg_mutex);
+	mutex_lock(&sit_i->sentry_lock);
+
+	/* direct_io'ed data is aligned to the segment for better performance */
+	if (direct_io && curseg->next_blkoff)
+		__allocate_new_segments(sbi, type);
+
+	*new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
+
+	/*
+	 * __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);
+
+	if (!__has_curseg_space(sbi, type))
+		sit_i->s_ops->allocate_segment(sbi, type, false);
+	/*
+	 * SIT information should be updated before segment allocation,
+	 * since SSR needs latest valid block information.
+	 */
+	refresh_sit_entry(sbi, old_blkaddr, *new_blkaddr);
+
+	mutex_unlock(&sit_i->sentry_lock);
+
+	if (page && IS_NODESEG(type))
+		fill_node_footer_blkaddr(page, NEXT_FREE_BLKADDR(sbi, curseg));
+
+	mutex_unlock(&curseg->curseg_mutex);
+}
+
+static void do_write_page(struct f2fs_sb_info *sbi, struct page *page,
+			struct f2fs_summary *sum,
+			struct f2fs_io_info *fio)
+{
+	int type = __get_segment_type(page, fio->type);
+
+	allocate_data_block(sbi, page, fio->blk_addr, &fio->blk_addr, sum, type);
+
+	/* writeout dirty page into bdev */
+	f2fs_submit_page_mbio(sbi, page, fio);
+}
+
+void write_meta_page(struct f2fs_sb_info *sbi, struct page *page)
+{
+	struct f2fs_io_info fio = {
+		.type = META,
+		.rw = WRITE_SYNC | REQ_META | REQ_PRIO,
+		.blk_addr = page->index,
+	};
+
+	set_page_writeback(page);
+	f2fs_submit_page_mbio(sbi, page, &fio);
+}
+
+void write_node_page(struct f2fs_sb_info *sbi, struct page *page,
+			unsigned int nid, struct f2fs_io_info *fio)
+{
+	struct f2fs_summary sum;
+	set_summary(&sum, nid, 0, 0);
+	do_write_page(sbi, page, &sum, fio);
+}
+
+void write_data_page(struct page *page, struct dnode_of_data *dn,
+				struct f2fs_io_info *fio)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
+	struct f2fs_summary sum;
+	struct node_info ni;
+
+	f2fs_bug_on(sbi, dn->data_blkaddr == NULL_ADDR);
+	get_node_info(sbi, dn->nid, &ni);
+	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
+	do_write_page(sbi, page, &sum, fio);
+	dn->data_blkaddr = fio->blk_addr;
+}
+
+void rewrite_data_page(struct page *page, struct f2fs_io_info *fio)
+{
+	stat_inc_inplace_blocks(F2FS_P_SB(page));
+	f2fs_submit_page_mbio(F2FS_P_SB(page), page, fio);
+}
+
+void recover_data_page(struct f2fs_sb_info *sbi,
+			struct page *page, struct f2fs_summary *sum,
+			block_t old_blkaddr, block_t new_blkaddr)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	struct curseg_info *curseg;
+	unsigned int segno, old_cursegno;
+	struct seg_entry *se;
+	int type;
+
+	segno = GET_SEGNO(sbi, new_blkaddr);
+	se = get_seg_entry(sbi, segno);
+	type = se->type;
+
+	if (se->valid_blocks == 0 && !IS_CURSEG(sbi, segno)) {
+		if (old_blkaddr == NULL_ADDR)
+			type = CURSEG_COLD_DATA;
+		else
+			type = CURSEG_WARM_DATA;
+	}
+	curseg = CURSEG_I(sbi, type);
+
+	mutex_lock(&curseg->curseg_mutex);
+	mutex_lock(&sit_i->sentry_lock);
+
+	old_cursegno = curseg->segno;
+
+	/* change the current segment */
+	if (segno != curseg->segno) {
+		curseg->next_segno = segno;
+		change_curseg(sbi, type, true);
+	}
+
+	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
+	__add_sum_entry(sbi, type, sum);
+
+	refresh_sit_entry(sbi, old_blkaddr, new_blkaddr);
+	locate_dirty_segment(sbi, old_cursegno);
+
+	mutex_unlock(&sit_i->sentry_lock);
+	mutex_unlock(&curseg->curseg_mutex);
+}
+
+static inline bool is_merged_page(struct f2fs_sb_info *sbi,
+					struct page *page, enum page_type type)
+{
+	enum page_type btype = PAGE_TYPE_OF_BIO(type);
+	struct f2fs_bio_info *io = &sbi->write_io[btype];
+	struct bio_vec *bvec;
+	int i;
+
+	down_read(&io->io_rwsem);
+	if (!io->bio)
+		goto out;
+
+	bio_for_each_segment_all(bvec, io->bio, i) {
+		if (page == bvec->bv_page) {
+			up_read(&io->io_rwsem);
+			return true;
+		}
+	}
+
+out:
+	up_read(&io->io_rwsem);
+	return false;
+}
+
+void f2fs_wait_on_page_writeback(struct page *page,
+				enum page_type type)
+{
+	if (PageWriteback(page)) {
+		struct f2fs_sb_info *sbi = F2FS_P_SB(page);
+
+		if (is_merged_page(sbi, page, type))
+			f2fs_submit_merged_bio(sbi, type, WRITE);
+		wait_on_page_writeback(page);
+	}
+}
+
+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 = get_meta_page(sbi, start++);
+	kaddr = (unsigned char *)page_address(page);
+
+	/* Step 1: restore nat cache */
+	seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	memcpy(&seg_i->sum_blk->n_nats, kaddr, SUM_JOURNAL_SIZE);
+
+	/* Step 2: restore sit cache */
+	seg_i = CURSEG_I(sbi, CURSEG_COLD_DATA);
+	memcpy(&seg_i->sum_blk->n_sits, 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_CACHE_SIZE -
+						SUM_FOOTER_SIZE)
+				continue;
+
+			f2fs_put_page(page, 1);
+			page = NULL;
+
+			page = get_meta_page(sbi, start++);
+			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;
+
+	/* 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 = get_meta_page(sbi, blk_addr);
+	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 {
+			int err;
+
+			err = restore_node_summary(sbi, segno, sum);
+			if (err) {
+				f2fs_put_page(new, 1);
+				return err;
+			}
+		}
+	}
+
+	/* set uncompleted segment to curseg */
+	curseg = CURSEG_I(sbi, type);
+	mutex_lock(&curseg->curseg_mutex);
+	memcpy(curseg->sum_blk, sum, PAGE_CACHE_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);
+	f2fs_put_page(new, 1);
+	return 0;
+}
+
+static int restore_curseg_summaries(struct f2fs_sb_info *sbi)
+{
+	int type = CURSEG_HOT_DATA;
+	int err;
+
+	if (is_set_ckpt_flags(F2FS_CKPT(sbi), CP_COMPACT_SUM_FLAG)) {
+		int npages = npages_for_summary_flush(sbi, true);
+
+		if (npages >= 2)
+			ra_meta_pages(sbi, start_sum_block(sbi), npages,
+								META_CP);
+
+		/* restore for compacted data summary */
+		if (read_compacted_summaries(sbi))
+			return -EINVAL;
+		type = CURSEG_HOT_NODE;
+	}
+
+	if (__exist_node_summaries(sbi))
+		ra_meta_pages(sbi, sum_blk_addr(sbi, NR_CURSEG_TYPE, type),
+					NR_CURSEG_TYPE - type, META_CP);
+
+	for (; type <= CURSEG_COLD_NODE; type++) {
+		err = read_normal_summaries(sbi, type);
+		if (err)
+			return err;
+	}
+
+	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 = grab_meta_page(sbi, blkaddr++);
+	kaddr = (unsigned char *)page_address(page);
+
+	/* Step 1: write nat cache */
+	seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	memcpy(kaddr, &seg_i->sum_blk->n_nats, 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->sum_blk->n_sits,
+						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 = grab_meta_page(sbi, blkaddr++);
+				kaddr = (unsigned char *)page_address(page);
+				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_CACHE_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++) {
+		struct curseg_info *sum = CURSEG_I(sbi, i);
+		mutex_lock(&sum->curseg_mutex);
+		write_sum_page(sbi, sum->sum_blk, blkaddr + (i - type));
+		mutex_unlock(&sum->curseg_mutex);
+	}
+}
+
+void write_data_summaries(struct f2fs_sb_info *sbi, block_t start_blk)
+{
+	if (is_set_ckpt_flags(F2FS_CKPT(sbi), CP_COMPACT_SUM_FLAG))
+		write_compacted_summaries(sbi, start_blk);
+	else
+		write_normal_summaries(sbi, start_blk, CURSEG_HOT_DATA);
+}
+
+void write_node_summaries(struct f2fs_sb_info *sbi, block_t start_blk)
+{
+	write_normal_summaries(sbi, start_blk, CURSEG_HOT_NODE);
+}
+
+int lookup_journal_in_cursum(struct f2fs_summary_block *sum, int type,
+					unsigned int val, int alloc)
+{
+	int i;
+
+	if (type == NAT_JOURNAL) {
+		for (i = 0; i < nats_in_cursum(sum); i++) {
+			if (le32_to_cpu(nid_in_journal(sum, i)) == val)
+				return i;
+		}
+		if (alloc && nats_in_cursum(sum) < NAT_JOURNAL_ENTRIES)
+			return update_nats_in_cursum(sum, 1);
+	} else if (type == SIT_JOURNAL) {
+		for (i = 0; i < sits_in_cursum(sum); i++)
+			if (le32_to_cpu(segno_in_journal(sum, i)) == val)
+				return i;
+		if (alloc && sits_in_cursum(sum) < SIT_JOURNAL_ENTRIES)
+			return update_sits_in_cursum(sum, 1);
+	}
+	return -1;
+}
+
+static struct page *get_current_sit_page(struct f2fs_sb_info *sbi,
+					unsigned int segno)
+{
+	return get_meta_page(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 *src_page, *dst_page;
+	pgoff_t src_off, dst_off;
+	void *src_addr, *dst_addr;
+
+	src_off = current_sit_addr(sbi, start);
+	dst_off = next_sit_addr(sbi, src_off);
+
+	/* get current sit block page without lock */
+	src_page = get_meta_page(sbi, src_off);
+	dst_page = grab_meta_page(sbi, dst_off);
+	f2fs_bug_on(sbi, PageDirty(src_page));
+
+	src_addr = page_address(src_page);
+	dst_addr = page_address(dst_page);
+	memcpy(dst_addr, src_addr, PAGE_CACHE_SIZE);
+
+	set_page_dirty(dst_page);
+	f2fs_put_page(src_page, 1);
+
+	set_to_next_sit(sit_i, start);
+
+	return dst_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_ATOMIC);
+
+	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_summary_block *sum = curseg->sum_blk;
+	int i;
+
+	for (i = sits_in_cursum(sum) - 1; i >= 0; i--) {
+		unsigned int segno;
+		bool dirtied;
+
+		segno = le32_to_cpu(segno_in_journal(sum, i));
+		dirtied = __mark_sit_entry_dirty(sbi, segno);
+
+		if (!dirtied)
+			add_sit_entry(segno, &SM_I(sbi)->sit_entry_set);
+	}
+	update_sits_in_cursum(sum, -sits_in_cursum(sum));
+}
+
+/*
+ * CP calls this function, which flushes SIT entries including sit_journal,
+ * and moves prefree segs to free segs.
+ */
+void 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_summary_block *sum = curseg->sum_blk;
+	struct sit_entry_set *ses, *tmp;
+	struct list_head *head = &SM_I(sbi)->sit_entry_set;
+	bool to_journal = true;
+	struct seg_entry *se;
+
+	mutex_lock(&curseg->curseg_mutex);
+	mutex_lock(&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(sum, 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(sum, ses->entry_cnt, SIT_JOURNAL))
+			to_journal = false;
+
+		if (!to_journal) {
+			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);
+
+			/* add discard candidates */
+			if (cpc->reason != CP_DISCARD) {
+				cpc->trim_start = segno;
+				add_discard_addrs(sbi, cpc);
+			}
+
+			if (to_journal) {
+				offset = lookup_journal_in_cursum(sum,
+							SIT_JOURNAL, segno, 1);
+				f2fs_bug_on(sbi, offset < 0);
+				segno_in_journal(sum, offset) =
+							cpu_to_le32(segno);
+				seg_info_to_raw_sit(se,
+						&sit_in_journal(sum, offset));
+			} else {
+				sit_offset = SIT_ENTRY_OFFSET(sit_i, segno);
+				seg_info_to_raw_sit(se,
+						&raw_sit->entries[sit_offset]);
+			}
+
+			__clear_bit(segno, bitmap);
+			sit_i->dirty_sentries--;
+			ses->entry_cnt--;
+		}
+
+		if (!to_journal)
+			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) {
+		for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
+			add_discard_addrs(sbi, cpc);
+	}
+	mutex_unlock(&sit_i->sentry_lock);
+	mutex_unlock(&curseg->curseg_mutex);
+
+	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 f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
+	struct sit_info *sit_i;
+	unsigned int sit_segs, start;
+	char *src_bitmap, *dst_bitmap;
+	unsigned int bitmap_size;
+
+	/* allocate memory for SIT information */
+	sit_i = kzalloc(sizeof(struct sit_info), GFP_KERNEL);
+	if (!sit_i)
+		return -ENOMEM;
+
+	SM_I(sbi)->sit_info = sit_i;
+
+	sit_i->sentries = vzalloc(MAIN_SEGS(sbi) * sizeof(struct seg_entry));
+	if (!sit_i->sentries)
+		return -ENOMEM;
+
+	bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi));
+	sit_i->dirty_sentries_bitmap = kzalloc(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
+			= kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+		sit_i->sentries[start].ckpt_valid_map
+			= kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+		if (!sit_i->sentries[start].cur_valid_map
+				|| !sit_i->sentries[start].ckpt_valid_map)
+			return -ENOMEM;
+	}
+
+	sit_i->tmp_map = kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+	if (!sit_i->tmp_map)
+		return -ENOMEM;
+
+	if (sbi->segs_per_sec > 1) {
+		sit_i->sec_entries = vzalloc(MAIN_SECS(sbi) *
+					sizeof(struct sec_entry));
+		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);
+
+	dst_bitmap = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL);
+	if (!dst_bitmap)
+		return -ENOMEM;
+
+	/* 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 = le64_to_cpu(ckpt->valid_block_count);
+	sit_i->sit_bitmap = dst_bitmap;
+	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 = CURRENT_TIME_SEC.tv_sec;
+	mutex_init(&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 = kzalloc(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 = kmalloc(bitmap_size, GFP_KERNEL);
+	if (!free_i->free_segmap)
+		return -ENOMEM;
+
+	sec_bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
+	free_i->free_secmap = kmalloc(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 = kcalloc(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 = kzalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
+		if (!array[i].sum_blk)
+			return -ENOMEM;
+		array[i].segno = NULL_SEGNO;
+		array[i].next_blkoff = 0;
+	}
+	return restore_curseg_summaries(sbi);
+}
+
+static void 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_summary_block *sum = curseg->sum_blk;
+	int sit_blk_cnt = SIT_BLK_CNT(sbi);
+	unsigned int i, start, end;
+	unsigned int readed, start_blk = 0;
+	int nrpages = MAX_BIO_BLOCKS(sbi);
+
+	do {
+		readed = ra_meta_pages(sbi, start_blk, nrpages, META_SIT);
+
+		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 seg_entry *se = &sit_i->sentries[start];
+			struct f2fs_sit_block *sit_blk;
+			struct f2fs_sit_entry sit;
+			struct page *page;
+
+			mutex_lock(&curseg->curseg_mutex);
+			for (i = 0; i < sits_in_cursum(sum); i++) {
+				if (le32_to_cpu(segno_in_journal(sum, i))
+								== start) {
+					sit = sit_in_journal(sum, i);
+					mutex_unlock(&curseg->curseg_mutex);
+					goto got_it;
+				}
+			}
+			mutex_unlock(&curseg->curseg_mutex);
+
+			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);
+got_it:
+			check_block_count(sbi, start, &sit);
+			seg_info_from_raw_sit(se, &sit);
+			if (sbi->segs_per_sec > 1) {
+				struct sec_entry *e = get_sec_entry(sbi, start);
+				e->valid_blocks += se->valid_blocks;
+			}
+		}
+		start_blk += readed;
+	} while (start_blk < sit_blk_cnt);
+}
+
+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);
+	}
+
+	/* 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, 0);
+		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 = kzalloc(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 = kzalloc(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] = kzalloc(bitmap_size, GFP_KERNEL);
+		if (!dirty_i->dirty_segmap[i])
+			return -ENOMEM;
+	}
+
+	init_dirty_segmap(sbi);
+	return init_victim_secmap(sbi);
+}
+
+/*
+ * 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;
+
+	mutex_lock(&sit_i->sentry_lock);
+
+	sit_i->min_mtime = LLONG_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);
+	mutex_unlock(&sit_i->sentry_lock);
+}
+
+int 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 = kzalloc(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;
+	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;
+
+	INIT_LIST_HEAD(&sm_info->discard_list);
+	sm_info->nr_discards = 0;
+	sm_info->max_discards = 0;
+
+	sm_info->trim_sections = DEF_BATCHED_TRIM_SECTIONS;
+
+	INIT_LIST_HEAD(&sm_info->sit_entry_set);
+
+	if (test_opt(sbi, FLUSH_MERGE) && !f2fs_readonly(sbi->sb)) {
+		err = create_flush_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 */
+	build_sit_entries(sbi);
+
+	init_free_segmap(sbi);
+	err = build_dirty_segmap(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);
+	kfree(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);
+	kfree(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);
+}
+
+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;
+	kfree(free_i->free_segmap);
+	kfree(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);
+			kfree(sit_i->sentries[start].ckpt_valid_map);
+		}
+	}
+	kfree(sit_i->tmp_map);
+
+	vfree(sit_i->sentries);
+	vfree(sit_i->sec_entries);
+	kfree(sit_i->dirty_sentries_bitmap);
+
+	SM_I(sbi)->sit_info = NULL;
+	kfree(sit_i->sit_bitmap);
+	kfree(sit_i);
+}
+
+void destroy_segment_manager(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_sm_info *sm_info = SM_I(sbi);
+
+	if (!sm_info)
+		return;
+	destroy_flush_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 create_segment_manager_caches(void)
+{
+	discard_entry_slab = f2fs_kmem_cache_create("discard_entry",
+			sizeof(struct discard_entry));
+	if (!discard_entry_slab)
+		goto fail;
+
+	sit_entry_set_slab = f2fs_kmem_cache_create("sit_entry_set",
+			sizeof(struct sit_entry_set));
+	if (!sit_entry_set_slab)
+		goto destory_discard_entry;
+
+	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);
+destory_discard_entry:
+	kmem_cache_destroy(discard_entry_slab);
+fail:
+	return -ENOMEM;
+}
+
+void destroy_segment_manager_caches(void)
+{
+	kmem_cache_destroy(sit_entry_set_slab);
+	kmem_cache_destroy(discard_entry_slab);
+	kmem_cache_destroy(inmem_entry_slab);
+}