On 2017/8/26 20:49, Yunlong Song wrote:
> 1. write file A with 5 blocks to current empty active segment
> 2. remove file A
> 3. write checkpoint
> 4. write file B with 507 blocks to the same active segment
>
> If file B is alive all the time, the blocks used by file A will never be
> discarded. So current active segment should also be treated as a candidate
> for small discards.
I don't think that would be a big issue, since there will not be any freezing
log headers, once log header moves, later invalid blocks could be discarded.
Thanks,
>
> Signed-off-by: Yunlong Song <yunlong.s...@huawei.com>
> ---
> 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 8375257..a2e7c8f 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1339,7 +1339,9 @@ static bool add_discard_addrs(struct f2fs_sb_info *sbi,
> struct cp_control *cpc,
> return false;
>
> if (!force) {
> - if (!test_opt(sbi, DISCARD) || !se->valid_blocks ||
> + if (!test_opt(sbi, DISCARD) ||
> + (!se->valid_blocks &&
> + !IS_CURSEG(sbi, cpc->trim_start)) ||
> SM_I(sbi)->dcc_info->nr_discards >=
> SM_I(sbi)->dcc_info->max_discards)
> return false;
>
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