diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ae758e8c245d..1693d4cb593b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -512,7 +512,7 @@ enum nid_list {
 struct f2fs_nm_info {
 	block_t nat_blkaddr;		/* base disk address of NAT */
 	nid_t max_nid;			/* maximum possible node ids */
-	nid_t available_nids;		/* maximum available node ids */
+	nid_t available_nids;		/* # of available node ids */
 	nid_t next_scan_nid;		/* the next nid to be scanned */
 	unsigned int ram_thresh;	/* control the memory footprint */
 	unsigned int ra_nid_pages;	/* # of nid pages to be readaheaded */
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 1de25f871016..c1bbfdcf519d 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1884,11 +1884,13 @@ retry:
 	if (time_to_inject(sbi, FAULT_ALLOC_NID))
 		return false;
 #endif
-	if (unlikely(sbi->total_valid_node_count + 1 > nm_i->available_nids))
-		return false;
-
 	spin_lock(&nm_i->nid_list_lock);
 
+	if (unlikely(nm_i->available_nids == 0)) {
+		spin_unlock(&nm_i->nid_list_lock);
+		return false;
+	}
+
 	/* We should not use stale free nids created by build_free_nids */
 	if (nm_i->nid_cnt[FREE_NID_LIST] && !on_build_free_nids(nm_i)) {
 		f2fs_bug_on(sbi, list_empty(&nm_i->nid_list[FREE_NID_LIST]));
@@ -1899,6 +1901,7 @@ retry:
 		__remove_nid_from_list(sbi, i, FREE_NID_LIST, true);
 		i->state = NID_ALLOC;
 		__insert_nid_to_list(sbi, i, ALLOC_NID_LIST, false);
+		nm_i->available_nids--;
 		spin_unlock(&nm_i->nid_list_lock);
 		return true;
 	}
@@ -1950,6 +1953,9 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
 		i->state = NID_NEW;
 		__insert_nid_to_list(sbi, i, FREE_NID_LIST, false);
 	}
+
+	nm_i->available_nids++;
+
 	spin_unlock(&nm_i->nid_list_lock);
 
 	if (need_free)
@@ -2149,6 +2155,19 @@ static void remove_nats_in_journal(struct f2fs_sb_info *sbi)
 			ne = grab_nat_entry(nm_i, nid);
 			node_info_from_raw_nat(&ne->ni, &raw_ne);
 		}
+
+		/*
+		 * if a free nat in journal has not been used after last
+		 * checkpoint, we should remove it from available nids,
+		 * since later we will add it again.
+		 */
+		if (!get_nat_flag(ne, IS_DIRTY) &&
+				le32_to_cpu(raw_ne.block_addr) == NULL_ADDR) {
+			spin_lock(&nm_i->nid_list_lock);
+			nm_i->available_nids--;
+			spin_unlock(&nm_i->nid_list_lock);
+		}
+
 		__set_nat_cache_dirty(nm_i, ne);
 	}
 	update_nats_in_cursum(journal, -i);
@@ -2221,8 +2240,12 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
 		raw_nat_from_node_info(raw_ne, &ne->ni);
 		nat_reset_flag(ne);
 		__clear_nat_cache_dirty(NM_I(sbi), ne);
-		if (nat_get_blkaddr(ne) == NULL_ADDR)
+		if (nat_get_blkaddr(ne) == NULL_ADDR) {
 			add_free_nid(sbi, nid, false);
+			spin_lock(&NM_I(sbi)->nid_list_lock);
+			NM_I(sbi)->available_nids++;
+			spin_unlock(&NM_I(sbi)->nid_list_lock);
+		}
 	}
 
 	if (to_journal)
@@ -2297,7 +2320,8 @@ static int init_node_manager(struct f2fs_sb_info *sbi)
 	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
 
 	/* not used nids: 0, node, meta, (and root counted as valid node) */
-	nm_i->available_nids = nm_i->max_nid - F2FS_RESERVED_NODE_NUM;
+	nm_i->available_nids = nm_i->max_nid - sbi->total_valid_node_count -
+							F2FS_RESERVED_NODE_NUM;
 	nm_i->nid_cnt[FREE_NID_LIST] = 0;
 	nm_i->nid_cnt[ALLOC_NID_LIST] = 0;
 	nm_i->nat_cnt = 0;