3 files changed, 40 insertions, 11 deletions

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 5cd19fdc1059..7e497f5b349c 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1811,6 +1811,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
 	};
 	unsigned int skipped_round = 0, round = 0;
+	unsigned int upper_secs;
 
 	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
 				gc_control->nr_free_secs,
@@ -1896,8 +1897,13 @@ retry:
 		}
 	}
 
-	/* Write checkpoint to reclaim prefree segments */
-	if (free_sections(sbi) < NR_CURSEG_PERSIST_TYPE &&
+	__get_secs_required(sbi, NULL, &upper_secs, NULL);
+
+	/*
+	 * Write checkpoint to reclaim prefree segments.
+	 * We need more three extra sections for writer's data/node/dentry.
+	 */
+	if (free_sections(sbi) <= upper_secs + NR_GC_CHECKPOINT_SECS &&
 				prefree_segments(sbi)) {
 		ret = f2fs_write_checkpoint(sbi, &cpc);
 		if (ret)
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index ca84024b9c9e..47357101b03c 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -30,6 +30,8 @@
 /* Search max. number of dirty segments to select a victim segment */
 #define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */
 
+#define NR_GC_CHECKPOINT_SECS (3)	/* data/node/dentry sections */
+
 struct f2fs_gc_kthread {
 	struct task_struct *f2fs_gc_task;
 	wait_queue_head_t gc_wait_queue_head;
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index cd65778fc982..f3951e8ad394 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -608,8 +608,12 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi,
 	return true;
 }
 
-static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi,
-					int freed, int needed)
+/*
+ * calculate needed sections for dirty node/dentry
+ * and call has_curseg_enough_space
+ */
+static inline void __get_secs_required(struct f2fs_sb_info *sbi,
+		unsigned int *lower_p, unsigned int *upper_p, bool *curseg_p)
 {
 	unsigned int total_node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) +
 					get_pages(sbi, F2FS_DIRTY_DENTS) +
@@ -619,20 +623,37 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi,
 	unsigned int dent_secs = total_dent_blocks / CAP_BLKS_PER_SEC(sbi);
 	unsigned int node_blocks = total_node_blocks % CAP_BLKS_PER_SEC(sbi);
 	unsigned int dent_blocks = total_dent_blocks % CAP_BLKS_PER_SEC(sbi);
-	unsigned int free, need_lower, need_upper;
+
+	if (lower_p)
+		*lower_p = node_secs + dent_secs;
+	if (upper_p)
+		*upper_p = node_secs + dent_secs +
+			(node_blocks ? 1 : 0) + (dent_blocks ? 1 : 0);
+	if (curseg_p)
+		*curseg_p = has_curseg_enough_space(sbi,
+				node_blocks, dent_blocks);
+}
+
+static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi,
+					int freed, int needed)
+{
+	unsigned int free_secs, lower_secs, upper_secs;
+	bool curseg_space;
 
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
 		return false;
 
-	free = free_sections(sbi) + freed;
-	need_lower = node_secs + dent_secs + reserved_sections(sbi) + needed;
-	need_upper = need_lower + (node_blocks ? 1 : 0) + (dent_blocks ? 1 : 0);
+	__get_secs_required(sbi, &lower_secs, &upper_secs, &curseg_space);
+
+	free_secs = free_sections(sbi) + freed;
+	lower_secs += needed + reserved_sections(sbi);
+	upper_secs += needed + reserved_sections(sbi);
 
-	if (free > need_upper)
+	if (free_secs > upper_secs)
 		return false;
-	else if (free <= need_lower)
+	else if (free_secs <= lower_secs)
 		return true;
-	return !has_curseg_enough_space(sbi, node_blocks, dent_blocks);
+	return !curseg_space;
 }
 
 static inline bool f2fs_is_checkpoint_ready(struct f2fs_sb_info *sbi)