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From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Cc:     Byungki Lee <dominicus79@gmail.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>
Subject: [PATCH 1/2] f2fs: write checkpoint during FG_GC
Date:   Tue,  3 May 2022 13:30:39 -0700
Message-Id: <20220503203040.365028-1-jaegeuk@kernel.org>
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From: Byungki Lee <dominicus79@gmail.com>

If there's not enough free sections each of which consistis of large segments,
we can hit no free section for upcoming section allocation. Let's reclaim some
prefree segments by writing checkpoints.

Signed-off-by: Byungki Lee <dominicus79@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/gc.c | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index eddd2e81a2a2..4d47723523c3 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1841,23 +1841,31 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 	if (sync)
 		goto stop;
 
-	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
-		if (skipped_round <= MAX_SKIP_GC_COUNT ||
-					skipped_round * 2 < round) {
-			segno = NULL_SEGNO;
-			goto gc_more;
-		}
+	if (!has_not_enough_free_secs(sbi, sec_freed, 0))
+		goto stop;
 
-		if (first_skipped < last_skipped &&
-				(last_skipped - first_skipped) >
-						sbi->skipped_gc_rwsem) {
-			f2fs_drop_inmem_pages_all(sbi, true);
-			segno = NULL_SEGNO;
-			goto gc_more;
-		}
-		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
+	if (skipped_round <= MAX_SKIP_GC_COUNT || skipped_round * 2 < round) {
+
+		/* Write checkpoint to reclaim prefree segments */
+		if (free_sections(sbi) < NR_CURSEG_PERSIST_TYPE &&
+				prefree_segments(sbi) &&
+				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
 			ret = f2fs_write_checkpoint(sbi, &cpc);
-	}
+			if (ret)
+				goto stop;
+		}
+		segno = NULL_SEGNO;
+		goto gc_more;
+	}
+	if (first_skipped < last_skipped &&
+			(last_skipped - first_skipped) >
+					sbi->skipped_gc_rwsem) {
+		f2fs_drop_inmem_pages_all(sbi, true);
+		segno = NULL_SEGNO;
+		goto gc_more;
+	}
+	if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
+		ret = f2fs_write_checkpoint(sbi, &cpc);
 stop:
 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
-- 
2.36.0.464.gb9c8b46e94-goog