linux-kernel - [PATCH v2] f2fs: fix uninitialized skipped_gc

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Message-ID: <20230216072821epcms2p35e1fecca382380723ac0031862687173@epcms2p3>
Date:   Thu, 16 Feb 2023 16:28:21 +0900
From:   Yonggil Song <yonggil.song@...sung.com>
To:     Chao Yu <chao@...nel.org>,
        "jaegeuk@...nel.org" <jaegeuk@...nel.org>,
        "linux-f2fs-devel@...ts.sourceforge.net" 
        <linux-f2fs-devel@...ts.sourceforge.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "daehojeong@...gle.com" <daehojeong@...gle.com>
CC:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        Seokhwan Kim <sukka.kim@...sung.com>,
        Daejun Park <daejun7.park@...sung.com>
Subject: [PATCH v2] f2fs: fix uninitialized skipped_gc_rwsem

When f2fs skipped a gc round during victim migration, there was a bug which
would skip all upcoming gc rounds unconditionally because skipped_gc_rwsem
was not initialized. It fixes the bug by correctly initializing the
skipped_gc_rwsem inside the gc loop.

Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Signed-off-by: Yonggil Song <yonggil.song@...sung.com>

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index b22f49a6f128..81d326abaac1 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1786,8 +1786,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
 				prefree_segments(sbi));
 
 	cpc.reason = __get_cp_reason(sbi);
-	sbi->skipped_gc_rwsem = 0;
 gc_more:
+	sbi->skipped_gc_rwsem = 0;
 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
 		ret = -EINVAL;
 		goto stop;
-- 
2.34.1