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From:   Andiry Xu <jix024@eng.ucsd.edu>
To:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nvdimm@lists.01.org
Cc:     dan.j.williams@intel.com, andy.rudoff@intel.com,
        coughlan@redhat.com, swanson@cs.ucsd.edu, david@fromorbit.com,
        jack@suse.com, swhiteho@redhat.com, miklos@szeredi.hu,
        andiry.xu@gmail.com, Andiry Xu <jix024@cs.ucsd.edu>
Subject: [RFC v2 36/83] Journal: Lite journal recovery.
Date:   Sat, 10 Mar 2018 10:18:17 -0800
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From: Andiry Xu <jix024@cs.ucsd.edu>

Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
---
 fs/nova/journal.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/fs/nova/journal.c b/fs/nova/journal.c
index 75d590f..f31de97 100644
--- a/fs/nova/journal.c
+++ b/fs/nova/journal.c
@@ -106,3 +106,58 @@ static int nova_check_journal_entries(struct super_block *sb,
 
 	return 0;
 }
+
+/**************************** Journal Recovery ******************************/
+
+static void nova_undo_journal_entry(struct super_block *sb,
+	struct nova_lite_journal_entry *entry)
+{
+	u64 addr, value;
+
+	addr = le64_to_cpu(entry->data1);
+	value = le64_to_cpu(entry->data2);
+
+	*(u64 *)nova_get_block(sb, addr) = (u64)value;
+	nova_flush_buffer((void *)nova_get_block(sb, addr), CACHELINE_SIZE, 0);
+}
+
+static void nova_undo_lite_journal_entry(struct super_block *sb,
+	struct nova_lite_journal_entry *entry)
+{
+	u64 type;
+
+	type = le64_to_cpu(entry->type);
+
+	switch (type) {
+	case JOURNAL_INODE:
+		/* Currently unused */
+		break;
+	case JOURNAL_ENTRY:
+		nova_undo_journal_entry(sb, entry);
+		break;
+	default:
+		nova_dbg("%s: unknown data type %llu\n", __func__, type);
+		break;
+	}
+}
+
+/* Roll back all journal enries */
+static int nova_recover_lite_journal(struct super_block *sb,
+	struct journal_ptr_pair *pair)
+{
+	struct nova_lite_journal_entry *entry;
+	u64 temp;
+
+	temp = pair->journal_head;
+	while (temp != pair->journal_tail) {
+		entry = (struct nova_lite_journal_entry *)nova_get_block(sb,
+									temp);
+		nova_undo_lite_journal_entry(sb, entry);
+		temp = next_lite_journal(temp);
+	}
+
+	pair->journal_tail = pair->journal_head;
+	nova_flush_buffer(&pair->journal_head, CACHELINE_SIZE, 1);
+
+	return 0;
+}
-- 
2.7.4