Arnd,
> Unfortunately, the sector number is usually a 64-bit number, and
> we probably can't guarantee that bdev_zone_size() returns a
> power-of-two number, so we actually have to do the expensive 64-bit
> operation to get the remainder.
No, the zone size is guaranteed to be a power of 2. See sd_zbc.c in Jens
linux-block tree, branch for-4.10/block. So it is ok to do a
& (bdev_zone_size() - 1) for the remainder.
That was indeed my mistake in this patch. Modulo should not have been
used in the first place. My bad.
>
> Fixes: 792b84b74b54 ("f2fs: support multiple devices")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> fs/f2fs/segment.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 634834e5a232..e4c5497aa172 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -685,6 +685,7 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info
> *sbi,
> {
> sector_t nr_sects = SECTOR_FROM_BLOCK(blklen);
> sector_t sector;
> + u32 rem;
> int devi = 0;
>
> if (sbi->s_ndevs) {
> @@ -693,7 +694,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info
> *sbi,
> }
> sector = SECTOR_FROM_BLOCK(blkstart);
>
> - if (sector % bdev_zone_size(bdev) || nr_sects != bdev_zone_size(bdev)) {
> + div_u64_rem(sector, bdev_zone_size(bdev), &rem);
> + if (rem || nr_sects != bdev_zone_size(bdev)) {
> f2fs_msg(sbi->sb, KERN_INFO,
> "(%d) %s: Unaligned discard attempted (block %x + %x)",
> devi, sbi->s_ndevs ? FDEV(devi).path: "",
Thanks !
Best regards.
--
Damien Le Moal, Ph.D.
Sr Manager, System Software Research Group,
Western Digital
[email protected]
Tel: (+81) 0466-98-3593 (Ext. 51-3593)
1 kirihara-cho, Fujisawa, Kanagawa, 252-0888 Japan
www.wdc.com, www.hgst.com
