f2fs: add quick mode of checkpoint=disable for QA

This mode returns mount() quickly with EAGAIN. We can trigger this by
shutdown(F2FS_GOING_DOWN_NEED_FSCK).
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -1259,6 +1259,11 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	else
 		__clear_ckpt_flags(ckpt, CP_DISABLED_FLAG);
 
+	if (is_sbi_flag_set(sbi, SBI_CP_DISABLED_QUICK))
+		__set_ckpt_flags(ckpt, CP_DISABLED_QUICK_FLAG);
+	else
+		__clear_ckpt_flags(ckpt, CP_DISABLED_QUICK_FLAG);
+
 	if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
 		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
 	else

fs/f2fs/f2fs.h

@@ -191,6 +191,7 @@ enum {
 #define DEF_CP_INTERVAL			60	/* 60 secs */
 #define DEF_IDLE_INTERVAL		5	/* 5 secs */
 #define DEF_DISABLE_INTERVAL		5	/* 5 secs */
+#define DEF_DISABLE_QUICK_INTERVAL	1	/* 1 secs */
 #define DEF_UMOUNT_DISCARD_TIMEOUT	5	/* 5 secs */
 
 struct cp_control {
@@ -1101,6 +1102,7 @@ enum {
 	SBI_IS_SHUTDOWN,			/* shutdown by ioctl */
 	SBI_IS_RECOVERED,			/* recovered orphan/data */
 	SBI_CP_DISABLED,			/* CP was disabled last mount */
+	SBI_CP_DISABLED_QUICK,			/* CP was disabled quickly */
 	SBI_QUOTA_NEED_FLUSH,			/* need to flush quota info in CP */
 	SBI_QUOTA_SKIP_FLUSH,			/* skip flushing quota in current CP */
 	SBI_QUOTA_NEED_REPAIR,			/* quota file may be corrupted */

fs/f2fs/file.c

@@ -1972,11 +1972,11 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
 		break;
 	case F2FS_GOING_DOWN_NEED_FSCK:
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		set_sbi_flag(sbi, SBI_CP_DISABLED_QUICK);
+		set_sbi_flag(sbi, SBI_IS_DIRTY);
 		/* do checkpoint only */
 		ret = f2fs_sync_fs(sb, 1);
-		if (ret)
-			goto out;
-		break;
+		goto out;
 	default:
 		ret = -EINVAL;
 		goto out;

fs/f2fs/segment.c

@@ -868,6 +868,9 @@ int f2fs_disable_cp_again(struct f2fs_sb_info *sbi)
 
 	if (holes[DATA] > ovp || holes[NODE] > ovp)
 		return -EAGAIN;
+	if (is_sbi_flag_set(sbi, SBI_CP_DISABLED_QUICK) &&
+		dirty_segments(sbi) > overprovision_segments(sbi))
+		return -EAGAIN;
 	return 0;
 }
 

fs/f2fs/super.c

@@ -3205,6 +3205,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 
 	if (__is_set_ckpt_flags(F2FS_CKPT(sbi), CP_QUOTA_NEED_FSCK_FLAG))
 		set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+	if (__is_set_ckpt_flags(F2FS_CKPT(sbi), CP_DISABLED_QUICK_FLAG)) {
+		set_sbi_flag(sbi, SBI_CP_DISABLED_QUICK);
+		sbi->interval_time[DISABLE_TIME] = DEF_DISABLE_QUICK_INTERVAL;
+	}
 
 	/* Initialize device list */
 	err = f2fs_scan_devices(sbi);
@@ -3392,6 +3396,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 				cur_cp_version(F2FS_CKPT(sbi)));
 	f2fs_update_time(sbi, CP_TIME);
 	f2fs_update_time(sbi, REQ_TIME);
+	clear_sbi_flag(sbi, SBI_CP_DISABLED_QUICK);
 	return 0;
 
 free_meta:

include/linux/f2fs_fs.h

@@ -116,6 +116,7 @@ struct f2fs_super_block {
 /*
  * For checkpoint
  */
+#define CP_DISABLED_QUICK_FLAG		0x00002000
 #define CP_DISABLED_FLAG		0x00001000
 #define CP_QUOTA_NEED_FSCK_FLAG		0x00000800
 #define CP_LARGE_NAT_BITMAP_FLAG	0x00000400