btrfs: replace readpage_end_io_hook with direct calls

Don't call readpage_end_io_hook for the btree inode.  Instead of relying
on indirect calls to implement metadata buffer validation simply check
if the inode whose page we are processing equals the btree inode. If it
does call the necessary function.

This is an improvement in 2 directions:

1. We aren't paying the penalty of indirect calls in a post-speculation
   attacks world.

2. The function is now named more explicitly so it's obvious what's
   going on

This is in preparation to removing struct extent_io_ops altogether.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5cb8af6af25d..391c2b25cca1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2969,6 +2969,8 @@ void btrfs_inode_safe_disk_i_size_write(struct inode *inode, u64 new_i_size);
 u64 btrfs_file_extent_end(const struct btrfs_path *path);
 
 /* inode.c */
+int btrfs_verify_data_csum(struct btrfs_io_bio *io_bio, u64 phy_offset,
+			   struct page *page, u64 start, u64 end, int mirror);
 struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
 					   u64 start, u64 len);
 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,