RE: [f2fs-dev] [PATCH 2/2] f2fs: fix to overcome inline_data floods

From: Chao Yu
Date: Mon Jan 25 2016 - 04:50:00 EST


Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx]
> Sent: Sunday, January 24, 2016 4:16 AM
> To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx;
> linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 2/2] f2fs: fix to overcome inline_data floods
>
> The scenario is:
> 1. create lots of node blocks
> 2. sync
> 3. write lots of inline_data
> -> got panic due to no free space
>
> In that case, we should flush node blocks when writing inline_data in #3,
> and trigger gc as well.
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
> fs/f2fs/gc.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 0204433..8686231 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -838,8 +838,15 @@ gc_more:
>
> if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed)) {
> gc_type = FG_GC;
> + /*
> + * If there is no victim and no prefree segment but still not
> + * enough free sections, we should flush dent/node blocks and do
> + * garbage collections.
> + */
> if (__get_victim(sbi, &segno, gc_type) || prefree_segments(sbi))
> write_checkpoint(sbi, &cpc);
> + else if (has_not_enough_free_secs(sbi, 0))

I think this condition make checkpoint been triggered more frequently,
could we trigger cp when dent/node block exceed some threshold?

Thanks,

> + write_checkpoint(sbi, &cpc);
> }
>
> if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))
> --
> 2.6.3
>
>
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