On 2017/1/3 17:01, Yunlong Song wrote:
> In the small discard case, when se->valid_blocks is zero, the
> add_discard_addrs
> will directly return without __add_discard_entry. This will cause the file
> delete have no small discard. The case is like this:
>
> 1. Allocate free 2M segment
> 2. Write a file (size n blocks < 512) in that 2M segment, se->valid_blocks = n
> 3. Delete that file, se->valid_blocks = 0, add_discard_addrs will return
> without
> sending any discard of that file, and forever due to cur_map[i] ^ ckpt_map[i]
> =
> 0 after that checkpoint
Wouldn't it be discarded as prefree segment?
Thanks,
>
> Signed-off-by: Yunlong Song <yunlong.s...@huawei.com>
> ---
> fs/f2fs/segment.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0738f48..8610f14 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -838,7 +838,7 @@ static void add_discard_addrs(struct f2fs_sb_info *sbi,
> struct cp_control *cpc)
> return;
>
> if (!force) {
> - if (!test_opt(sbi, DISCARD) || !se->valid_blocks ||
> + if (!test_opt(sbi, DISCARD) ||
> SM_I(sbi)->nr_discards >= SM_I(sbi)->max_discards)
> return;
> }
>
