Re: [PATCH] btrfs: remove the inode cache check at btrfs_is_free_space_inode()

[Boris Burkov <boris@bur.io>]

On Wed, Jul 06, 2022 at 11:14:23AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> The inode cache feature was removed in kernel 5.11, and we no longer have
> any code that reads from or writes to inode caches. We may still mount a
> filesystem that has inode caches, but they are ignored.
> 
> Remove the check for an inode cache from btrfs_is_free_space_inode(),
> since we no longer have code to trigger reads from an inode cache or
> writes to an inode cache. The check at send.c is still needed, because
> in case we find a filesystem with an inode cache, we must ignore it.
> Also leave the checks at tree-checker.c, as they are sanity checks.
> 
> This eliminates a dead branch and reduces the amount of code since it's
> in an inline function.
> 
> Before:
> 
> $ size fs/btrfs/btrfs.ko
>    text	   data	    bss	    dec	    hex	filename
> 1620662	 189240	  29032	1838934	 1c0f56	fs/btrfs/btrfs.ko
> 
> After:
> 
> $ size fs/btrfs/btrfs.ko
>    text	   data	    bss	    dec	    hex	filename
> 1620502	 189240	  29032	1838774	 1c0eb6	fs/btrfs/btrfs.ko
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
> ---
>  fs/btrfs/btrfs_inode.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
> index 33811e896623..b467264bd1bb 100644
> --- a/fs/btrfs/btrfs_inode.h
> +++ b/fs/btrfs/btrfs_inode.h
> @@ -305,8 +305,7 @@ static inline bool btrfs_is_free_space_inode(struct btrfs_inode *inode)
>  	if (root == root->fs_info->tree_root &&
>  	    btrfs_ino(inode) != BTRFS_BTREE_INODE_OBJECTID)
>  		return true;
> -	if (inode->location.objectid == BTRFS_FREE_INO_OBJECTID)
> -		return true;
> +
>  	return false;
>  }
>  
> -- 
> 2.35.1
>