[PATCH] f2fs: fix to avoid potential reference count leak in do_garbage_collect()

[Chao Yu <chao@kernel.org>]

From: Chao Yu <chao@kernel.org>

In do_garbage_collect(), we have reserved reference counts on summary cache
of all segments, once gc_thread encounter freezing, we need to release all
reference counts.

Cc: stable@kernel.org
Cc: Daeho Jeong <daehojeong@google.com>
Fixes: 02d91398a602 ("f2fs: fix to freeze GC and discard threads quickly")
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/gc.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 5bb117e5e811..ad6f604cc27f 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1901,6 +1901,9 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 		if (block_end_segno > end_segno)
 			block_end_segno = end_segno;
 
+		if (unlikely(freezing(current)))
+			goto next_block;
+
 		if (is_cursec(sbi, GET_SEC_FROM_SEG(sbi, segno))) {
 			f2fs_err(sbi, "%s: segment %u is used by log",
 							__func__, segno);
@@ -1968,12 +1971,6 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 				sbi->next_victim_seg[gc_type] =
 					(cur_segno + 1 < sec_end_segno) ?
 					cur_segno + 1 : NULL_SEGNO;
-
-			if (unlikely(freezing(current))) {
-				f2fs_put_cache(sum_entry, false);
-				f2fs_put_cache(sum_entry, false);
-				goto stop;
-			}
 		}
 next_block:
 		f2fs_put_cache(sum_entry, false);
@@ -1981,7 +1978,6 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 		segno = block_end_segno;
 	}
 
-stop:
 	if (submitted)
 		f2fs_submit_merged_write(sbi, data_type);
 
-- 
2.49.0