btrfs: deal with errors when checking if a dir entry exists during log replay

btrfs: deal with errors when checking if a dir entry exists during log replay

Currently inode_in_dir() ignores errors returned from
btrfs_lookup_dir_index_item() and from btrfs_lookup_dir_item(), treating
any errors as if the directory entry does not exists in the fs/subvolume
tree, which is obviously not correct, as we can get errors such as -EIO
when reading extent buffers while searching the fs/subvolume's tree.

Fix that by making inode_in_dir() return the errors and making its only
caller, add_inode_ref(), deal with returned errors as well.

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