f2fs: give up CP_TRIMMED_FLAG if it drops discards

In ->umount, once we drop remained discard entries, we should not
set CP_TRIMMED_FLAG with another checkpoint.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -2553,7 +2553,7 @@ void init_discard_policy(struct discard_policy *dpolicy, int discard_type,
 						unsigned int granularity);
 void refresh_sit_entry(struct f2fs_sb_info *sbi, block_t old, block_t new);
 void stop_discard_thread(struct f2fs_sb_info *sbi);
-void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
+bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
 void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc);
 void release_discard_addrs(struct f2fs_sb_info *sbi);
 int npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);

fs/f2fs/segment.c

@@ -1196,12 +1196,13 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
 	return issued;
 }
 
-static void __drop_discard_cmd(struct f2fs_sb_info *sbi)
+static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	struct list_head *pend_list;
 	struct discard_cmd *dc, *tmp;
 	int i;
+	bool dropped = false;
 
 	mutex_lock(&dcc->cmd_lock);
 	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
@@ -1209,9 +1210,12 @@ static void __drop_discard_cmd(struct f2fs_sb_info *sbi)
 		list_for_each_entry_safe(dc, tmp, pend_list, list) {
 			f2fs_bug_on(sbi, dc->state != D_PREP);
 			__remove_discard_cmd(sbi, dc);
+			dropped = true;
 		}
 	}
 	mutex_unlock(&dcc->cmd_lock);
+
+	return dropped;
 }
 
 static void __wait_one_discard_bio(struct f2fs_sb_info *sbi,
@@ -1306,15 +1310,18 @@ void stop_discard_thread(struct f2fs_sb_info *sbi)
 }
 
 /* This comes from f2fs_put_super */
-void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
+bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	struct discard_policy dpolicy;
+	bool dropped;
 
 	init_discard_policy(&dpolicy, DPOLICY_UMOUNT, dcc->discard_granularity);
 	__issue_discard_cmd(sbi, &dpolicy);
-	__drop_discard_cmd(sbi);
+	dropped = __drop_discard_cmd(sbi);
 	__wait_all_discard_cmd(sbi, &dpolicy);
+
+	return dropped;
 }
 
 static int issue_discard_thread(void *data)

fs/f2fs/super.c

@@ -781,6 +781,7 @@ static void f2fs_put_super(struct super_block *sb)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
 	int i;
+	bool dropped;
 
 	f2fs_quota_off_umount(sb);
 
@@ -801,9 +802,9 @@ static void f2fs_put_super(struct super_block *sb)
 	}
 
 	/* be sure to wait for any on-going discard commands */
-	f2fs_wait_discard_bios(sbi);
+	dropped = f2fs_wait_discard_bios(sbi);
 
-	if (f2fs_discard_en(sbi) && !sbi->discard_blks) {
+	if (f2fs_discard_en(sbi) && !sbi->discard_blks && !dropped) {
 		struct cp_control cpc = {
 			.reason = CP_UMOUNT | CP_TRIMMED,
 		};