btrfs: cleanup extent buffer readahead

We're going to pass around more information when we allocate extent
buffers, in order to make that cleaner how we do readahead.  Most of the
callers have the parent node that we're getting our blockptr from, with
the sole exception of relocation which simply has the bytenr it wants to
read.

Add a helper that takes the current arguments that we need (bytenr and
gen), and add another helper for simply reading the slot out of a node.
In followup patches the helper that takes all the extra arguments will
be expanded, and the simpler helper won't need to have it's arguments
adjusted.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 238b45223f2e..009f505d6c97 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -45,7 +45,6 @@ int btrfs_verify_level_key(struct extent_buffer *eb, int level,
 struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
 				      u64 parent_transid, int level,
 				      struct btrfs_key *first_key);
-void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr);
 struct extent_buffer *btrfs_find_create_tree_block(
 						struct btrfs_fs_info *fs_info,
 						u64 bytenr);