btrfs: unexport repair_io_failure()

Function repair_io_failure() is no longer used out of extent_io.c since
commit 8b9b6f25 ("btrfs: scrub: cleanup the remaining nodatasum
fixup code"), which removes the last external caller.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -2282,7 +2282,7 @@ int free_io_failure(struct extent_io_tree *failure_tree,
  * currently, there can be no more than two copies of every data bit. thus,
  * exactly one rewrite is required.
  */
-int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
+static int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
 			     u64 length, u64 logical, struct page *page,
 			     unsigned int pg_offset, int mirror_num)
 {

fs/btrfs/extent_io.h

@@ -283,9 +283,6 @@ struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs);
 struct bio *btrfs_bio_clone(struct bio *bio);
 struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size);
 
-int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
-		      u64 length, u64 logical, struct page *page,
-		      unsigned int pg_offset, int mirror_num);
 void end_extent_writepage(struct page *page, int err, u64 start, u64 end);
 int btrfs_repair_eb_io_failure(const struct extent_buffer *eb, int mirror_num);