[RFC v2 35/83] Journal: Lite journal helper routines.

Andiry Xu
2018-03-10T18:21:05Z

fs/nova/Makefile | 2 +-
fs/nova/journal.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 109 insertions(+), 1 deletion(-)
create mode 100644 fs/nova/journal.c

diff --git a/fs/nova/Makefile b/fs/nova/Makefile
index b3638a4..4aeadea 100644
--- a/fs/nova/Makefile
+++ b/fs/nova/Makefile
@@ -4,4 +4,4 @@

obj-$(CONFIG_NOVA_FS) += nova.o

-nova-y := balloc.o bbuild.o inode.o log.o rebuild.o stats.o super.o
+nova-y := balloc.o bbuild.o inode.o journal.o log.o rebuild.o stats.o super.o
diff --git a/fs/nova/journal.c b/fs/nova/journal.c
new file mode 100644
index 0000000..75d590f
--- /dev/null
+++ b/fs/nova/journal.c
@@ -0,0 +1,108 @@
+/*
+ * NOVA journaling facility.
+ *
+ * This file contains journaling code to guarantee the atomicity of directory
+ * operations that span multiple inodes (unlink, rename, etc).
+ *
+ * Copyright 2015-2016 Regents of the University of California,
+ * UCSD Non-Volatile Systems Lab, Andiry Xu <jix024@cs.ucsd.edu>
+ * Copyright 2012-2013 Intel Corporation
+ * Copyright 2009-2011 Marco Stornelli <marco.stornelli@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/vfs.h>
+#include <linux/uaccess.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include "nova.h"
+#include "journal.h"
+
+/**************************** Lite journal ******************************/
+
+static inline void
+nova_print_lite_transaction(struct nova_lite_journal_entry *entry)
+{
+ nova_dbg("Entry %p: Type %llu, data1 0x%llx, data2 0x%llx\n, checksum %u\n",
+ entry, entry->type,
+ entry->data1, entry->data2, entry->csum);
+}
+
+static inline int nova_update_journal_entry_csum(struct super_block *sb,
+ struct nova_lite_journal_entry *entry)
+{
+ u32 crc = 0;
+
+ crc = nova_crc32c(~0, (__u8 *)entry,
+ (sizeof(struct nova_lite_journal_entry)
+ - sizeof(__le32)));
+
+ entry->csum = cpu_to_le32(crc);
+ nova_flush_buffer(entry, sizeof(struct nova_lite_journal_entry), 0);
+ return 0;
+}
+
+static inline int nova_check_entry_integrity(struct super_block *sb,
+ struct nova_lite_journal_entry *entry)
+{
+ u32 crc = 0;
+
+ crc = nova_crc32c(~0, (__u8 *)entry,
+ (sizeof(struct nova_lite_journal_entry)
+ - sizeof(__le32)));
+
+ if (entry->csum == cpu_to_le32(crc))
+ return 0;
+ else
+ return 1;
+}
+
+// Get the next journal entry. Journal entries are stored in a circular
+// buffer. They live a 1-page circular buffer.
+//
+// TODO: Add check to ensure that the journal doesn't grow too large.
+static inline u64 next_lite_journal(u64 curr_p)
+{
+ size_t size = sizeof(struct nova_lite_journal_entry);
+
+ if ((curr_p & (PAGE_SIZE - 1)) + size >= PAGE_SIZE)
+ return (curr_p & PAGE_MASK);
+
+ return curr_p + size;
+}
+
+// Walk the journal for one CPU, and verify the checksum on each entry.
+static int nova_check_journal_entries(struct super_block *sb,
+ struct journal_ptr_pair *pair)
+{
+ struct nova_lite_journal_entry *entry;
+ u64 temp;
+ int ret;
+
+ temp = pair->journal_head;
+ while (temp != pair->journal_tail) {
+ entry = (struct nova_lite_journal_entry *)nova_get_block(sb,
+ temp);
+ ret = nova_check_entry_integrity(sb, entry);
+ if (ret) {
+ nova_dbg("Entry %p checksum failure\n", entry);
+ nova_print_lite_transaction(entry);
+ return ret;
+ }
+ temp = next_lite_journal(temp);
+ }
+
+ return 0;
+}
--
2.7.4