f2fs: cover update_free_nid_bitmap with nid_list_lock

free_nid_bitmap and free_nid_count in update_free_nid_bitmap should be
updated atomically, use nid_list_lock cover them to avoid race in
concurrent scenario.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -565,7 +565,6 @@ struct f2fs_nm_info {
 	unsigned char (*free_nid_bitmap)[NAT_ENTRY_BITMAP_SIZE];
 	unsigned char *nat_block_bitmap;
 	unsigned short *free_nid_count;	/* free nid count of NAT block */
-	spinlock_t free_nid_lock;	/* protect updating of nid count */
 
 	/* for checkpoint */
 	char *nat_bitmap;		/* NAT bitmap pointer */

fs/f2fs/node.c

@@ -1815,7 +1815,7 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
 }
 
 static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
-			bool set, bool build, bool locked)
+							bool set, bool build)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid);
@@ -1829,14 +1829,10 @@ static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
 	else
 		__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
 
-	if (!locked)
-		spin_lock(&nm_i->free_nid_lock);
 	if (set)
 		nm_i->free_nid_count[nat_ofs]++;
 	else if (!build)
 		nm_i->free_nid_count[nat_ofs]--;
-	if (!locked)
-		spin_unlock(&nm_i->free_nid_lock);
 }
 
 static void scan_nat_page(struct f2fs_sb_info *sbi,
@@ -1865,7 +1861,9 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
 		f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
 		if (blk_addr == NULL_ADDR)
 			freed = add_free_nid(sbi, start_nid, true);
-		update_free_nid_bitmap(sbi, start_nid, freed, true, false);
+		spin_lock(&NM_I(sbi)->nid_list_lock);
+		update_free_nid_bitmap(sbi, start_nid, freed, true);
+		spin_unlock(&NM_I(sbi)->nid_list_lock);
 	}
 }
 
@@ -2020,7 +2018,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
 		__insert_nid_to_list(sbi, i, ALLOC_NID_LIST, false);
 		nm_i->available_nids--;
 
-		update_free_nid_bitmap(sbi, *nid, false, false, false);
+		update_free_nid_bitmap(sbi, *nid, false, false);
 
 		spin_unlock(&nm_i->nid_list_lock);
 		return true;
@@ -2076,7 +2074,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
 
 	nm_i->available_nids++;
 
-	update_free_nid_bitmap(sbi, nid, true, false, false);
+	update_free_nid_bitmap(sbi, nid, true, false);
 
 	spin_unlock(&nm_i->nid_list_lock);
 
@@ -2406,11 +2404,11 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
 			add_free_nid(sbi, nid, false);
 			spin_lock(&NM_I(sbi)->nid_list_lock);
 			NM_I(sbi)->available_nids++;
-			update_free_nid_bitmap(sbi, nid, true, false, false);
+			update_free_nid_bitmap(sbi, nid, true, false);
 			spin_unlock(&NM_I(sbi)->nid_list_lock);
 		} else {
 			spin_lock(&NM_I(sbi)->nid_list_lock);
-			update_free_nid_bitmap(sbi, nid, false, false, false);
+			update_free_nid_bitmap(sbi, nid, false, false);
 			spin_unlock(&NM_I(sbi)->nid_list_lock);
 		}
 	}
@@ -2535,10 +2533,10 @@ inline void load_free_nid_bitmap(struct f2fs_sb_info *sbi)
 		nid = i * NAT_ENTRY_PER_BLOCK;
 		last_nid = (i + 1) * NAT_ENTRY_PER_BLOCK;
 
-		spin_lock(&nm_i->free_nid_lock);
+		spin_lock(&NM_I(sbi)->nid_list_lock);
 		for (; nid < last_nid; nid++)
-			update_free_nid_bitmap(sbi, nid, true, true, true);
-		spin_unlock(&nm_i->free_nid_lock);
+			update_free_nid_bitmap(sbi, nid, true, true);
+		spin_unlock(&NM_I(sbi)->nid_list_lock);
 	}
 
 	for (i = 0; i < nm_i->nat_blocks; i++) {
@@ -2629,9 +2627,6 @@ static int init_free_nid_cache(struct f2fs_sb_info *sbi)
 					sizeof(unsigned short), GFP_KERNEL);
 	if (!nm_i->free_nid_count)
 		return -ENOMEM;
-
-	spin_lock_init(&nm_i->free_nid_lock);
-
 	return 0;
 }