Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Mime-Version: 1.0
Subject: [RESEND][PATCH] f2fs: avoid victim selection from previous victim
 section
Reply-To: yonggil.song@samsung.com
Sender: Yonggil Song <yonggil.song@samsung.com>
From:   Yonggil Song <yonggil.song@samsung.com>
To:     "jaegeuk@kernel.org" <jaegeuk@kernel.org>,
        "chao@kernel.org" <chao@kernel.org>,
        "linux-f2fs-devel@lists.sourceforge.net" 
        <linux-f2fs-devel@lists.sourceforge.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Message-ID: <20221122090320epcms2p2e5df6f7bb1c2d80ae69fd5e4f84b08be@epcms2p2>
Date:   Tue, 22 Nov 2022 18:03:20 +0900
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 102P
DLP-Filter: Pass
References: <CGME20221122090320epcms2p2e5df6f7bb1c2d80ae69fd5e4f84b08be@epcms2p2>
Precedence: bulk

When f2fs chooses GC victim in large section & LFS mode,
next_victim_seg[gc_type] is referenced first. After segment is freed,
next_victim_seg[gc_type] has the next segment number.
However, next_victim_seg[gc_type] still has the last segment number
even after the last segment of section is freed. In this case, when f2fs
chooses a victim for the next GC round, the last segment of previous victim
section is chosen as a victim.

Initialize next_victim_seg[gc_type] to NULL_SEGNO for the last segment in
large section.

Fixes: e3080b0120a1 ("f2fs: support subsectional garbage collection")
Signed-off-by: Yonggil Song <yonggil.song@samsung.com>
---
 fs/f2fs/gc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 0f967b1e98f2..f1b68eda2235 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1749,8 +1749,9 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 				get_valid_blocks(sbi, segno, false) == 0)
 			seg_freed++;
 
-		if (__is_large_section(sbi) && segno + 1 < end_segno)
-			sbi->next_victim_seg[gc_type] = segno + 1;
+		if (__is_large_section(sbi))
+			sbi->next_victim_seg[gc_type] =
+				(segno + 1 < end_segno) ? segno + 1 : NULL_SEGNO;
 skip:
 		f2fs_put_page(sum_page, 0);
 	}
-- 
2.34.1