--- zzzz-none-000/linux-3.10.107/fs/btrfs/compression.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/btrfs/compression.h	2021-02-04 17:41:59.000000000 +0000
@@ -45,7 +45,9 @@
 				  unsigned long nr_pages);
 int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 				 int mirror_num, unsigned long bio_flags);
-
+void btrfs_clear_biovec_end(struct bio_vec *bvec, int vcnt,
+				   unsigned long pg_index,
+				   unsigned long pg_offset);
 struct btrfs_compress_op {
 	struct list_head *(*alloc_workspace)(void);
 
@@ -75,7 +77,7 @@
 			  size_t srclen, size_t destlen);
 };
 
-extern struct btrfs_compress_op btrfs_zlib_compress;
-extern struct btrfs_compress_op btrfs_lzo_compress;
+extern const struct btrfs_compress_op btrfs_zlib_compress;
+extern const struct btrfs_compress_op btrfs_lzo_compress;
 
 #endif