f2fs: flush error flags in workqueue

In IRQ context, it wakes up workqueue to record errors into on-disk
superblock fields rather than in-memory fields.

Fixes: 1aa161e43106 ("f2fs: fix scheduling while atomic in decompression path")
Fixes: 95fa90c9e5a7 ("f2fs: support recording errors into superblock")
Signed-off-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/compress.c

···
 
 		/* Avoid f2fs_commit_super in irq context */
 		if (!in_task)
-			f2fs_save_errors(sbi, ERROR_FAIL_DECOMPRESSION);
+			f2fs_handle_error_async(sbi, ERROR_FAIL_DECOMPRESSION);
 		else
 			f2fs_handle_error(sbi, ERROR_FAIL_DECOMPRESSION);
 		goto out_release;

fs/f2fs/f2fs.h

···
 void f2fs_handle_critical_error(struct f2fs_sb_info *sbi, unsigned char reason,
 							bool irq_context);
 void f2fs_handle_error(struct f2fs_sb_info *sbi, unsigned char error);
+void f2fs_handle_error_async(struct f2fs_sb_info *sbi, unsigned char error);
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover);
 int f2fs_sync_fs(struct super_block *sb, int sync);
 int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi);

fs/f2fs/super.c

···
 	f2fs_down_write(&sbi->sb_lock);
 
 	spin_lock_irqsave(&sbi->error_lock, flags);
+	if (sbi->error_dirty) {
+		memcpy(F2FS_RAW_SUPER(sbi)->s_errors, sbi->errors,
+							MAX_F2FS_ERRORS);
+		sbi->error_dirty = false;
+	}
 	memcpy(raw_super->s_stop_reason, sbi->stop_reason, MAX_STOP_REASON);
 	spin_unlock_irqrestore(&sbi->error_lock, flags);
 
···
 	return need_update;
 }
 
-void f2fs_handle_error(struct f2fs_sb_info *sbi, unsigned char error)
+static void f2fs_record_errors(struct f2fs_sb_info *sbi, unsigned char error)
 {
 	int err;
-
-	f2fs_save_errors(sbi, error);
 
 	f2fs_down_write(&sbi->sb_lock);
 
···
 								error, err);
 out_unlock:
 	f2fs_up_write(&sbi->sb_lock);
+}
+
+void f2fs_handle_error(struct f2fs_sb_info *sbi, unsigned char error)
+{
+	f2fs_save_errors(sbi, error);
+	f2fs_record_errors(sbi, error);
+}
+
+void f2fs_handle_error_async(struct f2fs_sb_info *sbi, unsigned char error)
+{
+	f2fs_save_errors(sbi, error);
+
+	if (!sbi->error_dirty)
+		return;
+	if (!test_bit(error, (unsigned long *)sbi->errors))
+		return;
+	schedule_work(&sbi->s_error_work);
 }
 
 static bool system_going_down(void)