[PATCH v2 1/2] nilfs2: fix 64-bit division operations in nilfs_bmap_find_target_in_group()

[Jeff Layton]

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@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202603100602.KPxiClIO-lkp@xxxxxxxxx/
Reviewed-by: Viacheslav Dubeyko <slava@xxxxxxxxxxx>
Acked-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 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..abcf5252578ad24f694bfccf525893674bfcb4bc 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 index;
+
+	group = div_u64(bmap->b_inode->i_ino, entries_per_group);
+	div_u64_rem(bmap->b_inode->i_ino, NILFS_BMAP_GROUP_DIV, &index);
 
 	return group * entries_per_group +
-		(bmap->b_inode->i_ino % NILFS_BMAP_GROUP_DIV) *
-		(entries_per_group / NILFS_BMAP_GROUP_DIV);
+	       index * (entries_per_group / NILFS_BMAP_GROUP_DIV);
 }
 
 static struct lock_class_key nilfs_bmap_dat_lock_key;

-- 
2.53.0