btrfs: make btrfs_error_unpin_extent_range() return void

This helper is used in transaction abort or cleanup context and the
callers cannot handle all errors, only do best effort.

btrfs_cleanup_one_transaction
  btrfs_destroy_delayed_refs
    btrfs_error_unpin_extent_range
  btrfs_destroy_pinned_extent
    btrfs_error_unpin_extent_range
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -478,8 +478,7 @@ static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
 	return mapping_gfp_constraint(mapping, ~__GFP_FS);
 }
 
-int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
-				   u64 start, u64 end);
+void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 			 u64 num_bytes, u64 *actual_bytes);
 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);

fs/btrfs/extent-tree.c

@@ -6171,14 +6171,13 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
-				   u64 start, u64 end)
+/*
+ * Unpin the extent range in an error context and don't add the space back.
+ * Errors are not propagated further.
+ */
+void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end)
 {
-	int ret;
-
-	ret = unpin_extent_range(fs_info, start, end, false);
-	BUG_ON(ret);
-	return ret;
+	unpin_extent_range(fs_info, start, end, false);
 }
 
 /*