Re: [PATCH] btrfs: abort transaction in do_remap_reloc_trans() on failure

[Boris Burkov <boris@bur.io>]

On Tue, Apr 07, 2026 at 05:16:56PM +0100, Mark Harmstone wrote:
> If one of the calls made by do_remap_reloc_trans() fails, we can leave
> the remap tree in an inconsistent state. Abort the transaction if this
> happens, to prevent the corrupt state from reaching the disk.
> 
> Signed-off-by: Mark Harmstone <mark@harmstone.com>
> ---
>  fs/btrfs/relocation.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 1c42c5180bddd5..277a0042967665 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -5089,6 +5089,7 @@ static int do_remap_reloc_trans(struct btrfs_fs_info *fs_info,
>  	btrfs_free_reserved_extent(fs_info, new_addr, length, 0);
>  
>  	mutex_unlock(&fs_info->remap_mutex);
> +	btrfs_abort_transaction(trans, ret);

Counterintuitively to the usual pattern of sharing code in fail: labels,
I think it is quite nice to put a separate abort at each failing code
path that requires an abort. That way we get better diagnostic
information on what actually went wrong.

e.g. a recent patch from Filipe unfolding it across a function call:
https://lore.kernel.org/linux-btrfs/99743ac0b4b9a69dcaa8f9adcaf301bd1a0f1a89.1769163248.git.fdmanana@suse.com/

Thanks,
Boris

>  	btrfs_end_transaction(trans);
>  
>  	return ret;
> -- 
> 2.52.0
>