[PATCH 1/2] nilfs2: fix 64-bit division operations in nilfs_bmap_find_target_in_group()

[Ryusuke Konishi]

On Tue, Mar 10, 2026 at 8:44 PM Jeff Layton wrote:
>
> With the change to make inode->i_ino a u64, the build started failing on
> 32-bit ARM with:
>
>     ERROR: modpost: "__aeabi_uldivmod" [fs/nilfs2/nilfs2.ko] undefined!
>
> Fix this by using the 64-bit division interfaces in
> nilfs_bmap_find_target_in_group().
>
> Fixes: 998a59d371c2 ("treewide: fix missed i_ino format specifier conversions")
> Reported-by: kernel test robot <lkp at intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202603100602.KPxiClIO-lkp@intel.com/
> Signed-off-by: Jeff Layton <jlayton at kernel.org>

Acked-by: Ryusuke Konishi <konishi.ryusuke at gmail.com>

Thank you.  The conversion seems reasonable.

Ryusuke Konishi

> ---
>  fs/nilfs2/bmap.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
> index 824f2bd91c167965ec3a660202b6e6c5f1fe007e..4ce9a93149a5af13bc215cc1877a757e2c6cf49b 100644
> --- a/fs/nilfs2/bmap.c
> +++ b/fs/nilfs2/bmap.c
> @@ -455,11 +455,14 @@ __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *bmap)
>  {
>         struct inode *dat = nilfs_bmap_get_dat(bmap);
>         unsigned long entries_per_group = nilfs_palloc_entries_per_group(dat);
> -       unsigned long group = bmap->b_inode->i_ino / entries_per_group;
> +       unsigned long group;
> +       u32 rem;
> +
> +       group = div_u64(bmap->b_inode->i_ino, entries_per_group);
> +       div_u64_rem(bmap->b_inode->i_ino, NILFS_BMAP_GROUP_DIV, &rem);
>
>         return group * entries_per_group +
> -               (bmap->b_inode->i_ino % NILFS_BMAP_GROUP_DIV) *
> -               (entries_per_group / NILFS_BMAP_GROUP_DIV);
> +              rem * (entries_per_group / NILFS_BMAP_GROUP_DIV);
>  }
>
>  static struct lock_class_key nilfs_bmap_dat_lock_key;
>
> --
> 2.53.0
>