f2fs: add ovp valid_blocks check for bg gc victim to fg_gc

For foreground gc, greedy algorithm should be adapted, which makes
this formula work well:

	(2 * (100 / config.overprovision + 1) + 6)

But currently, we fg_gc have a prior to select bg_gc victim segments to gc
first, these victims are selected by cost-benefit algorithm, we can't guarantee
such segments have the small valid blocks, which may destroy the f2fs rule, on
the worstest case, would consume all the free segments.

This patch fix this by add a filter in check_bg_victims, if segment's has # of
valid blocks over overprovision ratio, skip such segments.

Cc: <stable@vger.kernel.org>
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 7b5e287ac127..146cc71ff91c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -890,6 +890,9 @@ struct f2fs_sb_info {
 	struct f2fs_gc_kthread	*gc_thread;	/* GC thread */
 	unsigned int cur_victim_sec;		/* current victim section num */
 
+	/* threshold for converting bg victims for fg */
+	u64 fggc_threshold;
+
 	/* maximum # of trials to find a victim segment for SSR and GC */
 	unsigned int max_victim_search;