Re: [PATCH 2/2] erofs-utils: lib: fix meta_blkaddr handling for 48-bit layout

[Gao Xiang <hsiangkao@linux.alibaba.com>]

On 2026/3/19 21:39, Ajay Rajera wrote:
> Fix the FIXME in metabox.c by properly handling meta_blkaddr for 48-bit layouts. In erofs_writesb(), set meta_blkaddr to 0 on-disk when 48-bit layout is enabled since meta_blkaddr is encoded differently in that mode. Remove the now-resolved FIXME comment in metabox.c as the issue is addressed in super.c.
> 
> Signed-off-by: Ajay Rajera <newajay.11r@gmail.com>
> ---
>   lib/metabox.c | 1 -
>   lib/super.c   | 2 +-
>   2 files changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/lib/metabox.c b/lib/metabox.c
> index d6abd51..077f88b 100644
> --- a/lib/metabox.c
> +++ b/lib/metabox.c
> @@ -62,7 +62,6 @@ int erofs_metadata_init(struct erofs_sb_info *sbi)
>   		if (ret)
>   			goto err_free;
>   		sbi->m2gr = m2gr;
> -		/* FIXME: sbi->meta_blkaddr should be 0 for 48-bit layouts */

I don't think it's a valid patch, I need to find more clue why
it was a FIXME.

>   		sbi->meta_blkaddr = EROFS_META_NEW_ADDR;
>   	}
>   
> diff --git a/lib/super.c b/lib/super.c
> index 088c9a0..99d2a24 100644
> --- a/lib/super.c
> +++ b/lib/super.c
> @@ -209,7 +209,7 @@ int erofs_writesb(struct erofs_sb_info *sbi)
>   		.epoch     = cpu_to_le64(sbi->epoch),
>   		.build_time = cpu_to_le64(sbi->build_time),
>   		.fixed_nsec = cpu_to_le32(sbi->fixed_nsec),
> -		.meta_blkaddr  = cpu_to_le32(sbi->meta_blkaddr),
> +		.meta_blkaddr  = cpu_to_le32(erofs_sb_has_48bit(sbi) ? 0 : sbi->meta_blkaddr),
>   		.xattr_blkaddr = cpu_to_le32(sbi->xattr_blkaddr),
>   		.xattr_prefix_count = sbi->xattr_prefix_count,
>   		.xattr_prefix_start = cpu_to_le32(sbi->xattr_prefix_start),