--- zzzz-none-000/linux-3.10.107/fs/btrfs/disk-io.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/btrfs/disk-io.h	2021-02-04 17:41:59.000000000 +0000
@@ -25,11 +25,12 @@
 #define BTRFS_SUPER_MIRROR_MAX	 3
 #define BTRFS_SUPER_MIRROR_SHIFT 12
 
-enum {
+enum btrfs_wq_endio_type {
 	BTRFS_WQ_ENDIO_DATA = 0,
 	BTRFS_WQ_ENDIO_METADATA = 1,
 	BTRFS_WQ_ENDIO_FREE_SPACE = 2,
 	BTRFS_WQ_ENDIO_RAID56 = 3,
+	BTRFS_WQ_ENDIO_DIO_REPAIR = 4,
 };
 
 static inline u64 btrfs_sb_offset(int mirror)
@@ -44,33 +45,74 @@
 struct btrfs_fs_devices;
 
 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
-				      u32 blocksize, u64 parent_transid);
-int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
-			 u64 parent_transid);
-int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
+				      u64 parent_transid);
+void readahead_tree_block(struct btrfs_root *root, u64 bytenr);
+int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
 			 int mirror_num, struct extent_buffer **eb);
 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
-						   u64 bytenr, u32 blocksize);
+						   u64 bytenr);
 void clean_tree_block(struct btrfs_trans_handle *trans,
-		      struct btrfs_root *root, struct extent_buffer *buf);
+		      struct btrfs_fs_info *fs_info, struct extent_buffer *buf);
 int open_ctree(struct super_block *sb,
 	       struct btrfs_fs_devices *fs_devices,
 	       char *options);
-int close_ctree(struct btrfs_root *root);
+void close_ctree(struct btrfs_root *root);
 int write_ctree_super(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root, int max_mirrors);
 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev);
+int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num,
+			struct buffer_head **bh_ret);
 int btrfs_commit_super(struct btrfs_root *root);
-struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
-					    u64 bytenr, u32 blocksize);
-struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
-					       struct btrfs_key *location);
-struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
-					      struct btrfs_key *location);
+struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
+					    u64 bytenr);
+struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
+				      struct btrfs_key *location);
+int btrfs_init_fs_root(struct btrfs_root *root);
+int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
+			 struct btrfs_root *root);
+void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);
+
+struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
+				     struct btrfs_key *key,
+				     bool check_ref);
+static inline struct btrfs_root *
+btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
+			   struct btrfs_key *location)
+{
+	return btrfs_get_fs_root(fs_info, location, true);
+}
+
 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);
 void btrfs_btree_balance_dirty(struct btrfs_root *root);
 void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root);
-void btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root);
+void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
+				 struct btrfs_root *root);
+void btrfs_free_fs_root(struct btrfs_root *root);
+
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+struct btrfs_root *btrfs_alloc_dummy_root(void);
+#endif
+
+/*
+ * This function is used to grab the root, and avoid it is freed when we
+ * access it. But it doesn't ensure that the tree is not dropped.
+ *
+ * If you want to ensure the whole tree is safe, you should use
+ * 	fs_info->subvol_srcu
+ */
+static inline struct btrfs_root *btrfs_grab_fs_root(struct btrfs_root *root)
+{
+	if (atomic_inc_not_zero(&root->refs))
+		return root;
+	return NULL;
+}
+
+static inline void btrfs_put_fs_root(struct btrfs_root *root)
+{
+	if (atomic_dec_and_test(&root->refs))
+		kfree(root);
+}
+
 void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
 			  int atomic);
@@ -79,7 +121,7 @@
 u32 btrfs_csum_data(char *data, u32 seed, size_t len);
 void btrfs_csum_final(u32 crc, char *result);
 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
-			int metadata);
+			enum btrfs_wq_endio_type metadata);
 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 			int rw, struct bio *bio, int mirror_num,
 			unsigned long bio_flags, u64 bio_offset,
@@ -99,8 +141,11 @@
 				     u64 objectid);
 int btree_lock_page_hook(struct page *page, void *data,
 				void (*flush_fn)(void *));
+int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
 int btrfs_calc_num_tolerated_disk_barrier_failures(
 	struct btrfs_fs_info *fs_info);
+int __init btrfs_end_io_wq_init(void);
+void btrfs_end_io_wq_exit(void);
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 void btrfs_init_lockdep(void);