Re: [PATCH] btrfs: print-tree: print header owner as signed

On Tue, Jun 23, 2026 at 08:25:40AM +0930, Qu Wenruo wrote:
> When dumpping a tree block, btrfs_header::owner is printed as
> unsigned, which can result in numbers that are hard to read, e.g:
> 
>  BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607
> 
> For the above output, 18446744073709551607 is (s64)-9, the root id of data
> reloc tree.
> 
> Despite those pre-defined root ids that are already negative, existing
> subvolume trees will not have any negative values, as subvolume trees can
> only utilize the lower 48 bits, so there will be no output change for
> existing subvolumes, thus no extra confusion.
> 

What do you think about a macro or function wrapping a switch statement
that also prints the string name of known trees? What about some identifying
info like a volume path for subvol trees? That one might be a stretch.

Anyway, this is already a definite improvement, thanks.
Reviewed-by: Boris Burkov <[email protected]>

> Signed-off-by: Qu Wenruo <[email protected]>
> ---
>  fs/btrfs/print-tree.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
> index 87e60a2d4bd8..53e726119ca7 100644
> --- a/fs/btrfs/print-tree.c
> +++ b/fs/btrfs/print-tree.c
> @@ -449,9 +449,9 @@ void btrfs_print_leaf(const struct extent_buffer *l)
>  	nr = btrfs_header_nritems(l);
>  
>  	btrfs_info(fs_info,
> -		   "leaf %llu gen %llu total ptrs %d free space %d owner %llu",
> +		   "leaf %llu gen %llu total ptrs %d free space %d owner %lld",
>  		   btrfs_header_bytenr(l), btrfs_header_generation(l), nr,
> -		   btrfs_leaf_free_space(l), btrfs_header_owner(l));
> +		   btrfs_leaf_free_space(l), (s64)btrfs_header_owner(l));
>  	print_eb_refs_lock(l);
>  	for (i = 0 ; i < nr ; i++) {
>  		char key_buf[KEY_TYPE_BUF_SIZE];
> @@ -600,10 +600,10 @@ void btrfs_print_tree(const struct extent_buffer *c, bool follow)
>  		return;
>  	}
>  	btrfs_info(fs_info,
> -		   "node %llu level %d gen %llu total ptrs %d free spc %u owner %llu",
> +		   "node %llu level %d gen %llu total ptrs %d free spc %u owner %lld",
>  		   btrfs_header_bytenr(c), level, btrfs_header_generation(c),
>  		   nr, (u32)BTRFS_NODEPTRS_PER_BLOCK(fs_info) - nr,
> -		   btrfs_header_owner(c));
> +		   (s64)btrfs_header_owner(c));
>  	print_eb_refs_lock(c);
>  	for (i = 0; i < nr; i++) {
>  		btrfs_node_key_to_cpu(c, &key, i);
> -- 
> 2.54.0
>