Hi Geert,
Since the original patch hasn't been merged to upstream, I think we can merge
this into original patch, how do you think?
On 2019/6/20 22:38, Geert Uytterhoeven wrote:
> On 32-bit (e.g. m68k):
>
> fs/f2fs/gc.o: In function `f2fs_resize_fs':
> gc.c:(.text+0x3056): undefined reference to `__umoddi3'
> gc.c:(.text+0x30c4): undefined reference to `__udivdi3'
>
> Fix this by using div_u64_rem() and div_u64() for 64-by-32 modulo resp.
> division operations.
>
> Reported-by: noreply@xxxxxxxxxxxxxx
> Fixes: d2ae7494d043bfaf ("f2fs: ioctl for removing a range from F2FS")
> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> ---
> This assumes BLKS_PER_SEC(sbi) is 32-bit.
>
> #define BLKS_PER_SEC(sbi) \
> ((sbi)->segs_per_sec * (sbi)->blocks_per_seg)
>
> Notes:
> 1. f2fs_sb_info.segs_per_sec and f2fs_sb_info.blocks_per_seg are both
> unsigned int,
> 2. The multiplication is done in 32-bit arithmetic, hence the result
> is of type unsigned int.
> 3. Is it guaranteed that the result will always fit in 32-bit, or can
> this overflow?
> 4. fs/f2fs/debug.c:update_sit_info() assigns BLKS_PER_SEC(sbi) to
> unsigned long long blks_per_sec, anticipating a 64-bit value.
> ---
> fs/f2fs/gc.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 5b1076505ade9f84..c65f87f11de029f4 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1438,13 +1438,15 @@ int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
> unsigned int secs;
> int gc_mode, gc_type;
> int err = 0;
> + __u32 rem;
>
> old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
> if (block_count > old_block_count)
> return -EINVAL;
>
> /* new fs size should align to section size */
> - if (block_count % BLKS_PER_SEC(sbi))
> + div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
> + if (rem)
> return -EINVAL;
>
> if (block_count == old_block_count)
> @@ -1463,7 +1465,7 @@ int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
> freeze_bdev(sbi->sb->s_bdev);
>
> shrunk_blocks = old_block_count - block_count;
> - secs = shrunk_blocks / BLKS_PER_SEC(sbi);
> + secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
> spin_lock(&sbi->stat_lock);
> if (shrunk_blocks + valid_user_blocks(sbi) +
> sbi->current_reserved_blocks + sbi->unusable_block_count +
>
