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nilfs2: fix 64-bit division operations in nilfs_bmap_find_target_in_group() 

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 udiv_u64() for the division.

For finding the index into the group, switch to using a bitwise &
operation since that's more efficient. With this change however,
NILFS_BMAP_GROUP_DIV must be a power of two, so add a compile-time
assertion for that.

Fixes: 998a59d371 ("treewide: fix missed i_ino format specifier conversions")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603100602.KPxiClIO-lkp@intel.com/
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260316-iino-u64-v3-2-d1076b8f7a20@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
master
Jeff Layton 2026-03-16 15:02:23 -04:00 committed by Christian Brauner
parent bef5b11087
commit 81359c146f
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 11 additions and 4 deletions
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15
fs/nilfs2/bmap.c
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@ -450,18 +450,25 @@ __u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *bmap, __u64 key)
return NILFS_BMAP_INVALID_PTR;
}
#define NILFS_BMAP_GROUP_DIV 8
#define NILFS_BMAP_GROUP_DIV 8 /* must be power of 2 */
__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;
BUILD_BUG_ON_NOT_POWER_OF_2(NILFS_BMAP_GROUP_DIV);
group = div_u64(bmap->b_inode->i_ino, entries_per_group);
index = bmap->b_inode->i_ino & (NILFS_BMAP_GROUP_DIV - 1);
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;
static struct lock_class_key nilfs_bmap_mdt_lock_key;