From 0f49c426fbd7265bdac09343e7c38f1df71ad71f Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Tue, 5 Oct 2010 10:14:48 -0400
Subject: Add rescue command to zero the log

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
 Makefile         |  3 +++
 btrfs-zero-log.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 btrfs-zero-log.c

diff --git a/Makefile b/Makefile
index 5178343e..6e6f6c68 100644
--- a/Makefile
+++ b/Makefile
@@ -59,6 +59,9 @@ mkfs.btrfs: $(objects) mkfs.o
 btrfs-debug-tree: $(objects) debug-tree.o
 	gcc $(CFLAGS) -o btrfs-debug-tree $(objects) debug-tree.o $(LDFLAGS) $(LIBS)
 
+btrfs-zero-log: $(objects) btrfs-zero-log.o
+	gcc $(CFLAGS) -o btrfs-zero-log $(objects) btrfs-zero-log.o $(LDFLAGS) $(LIBS)
+
 btrfstune: $(objects) btrfstune.o
 	gcc $(CFLAGS) -o btrfstune $(objects) btrfstune.o $(LDFLAGS) $(LIBS)
 
diff --git a/btrfs-zero-log.c b/btrfs-zero-log.c
new file mode 100644
index 00000000..f10438be
--- /dev/null
+++ b/btrfs-zero-log.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#define _XOPEN_SOURCE 500
+#define _GNU_SOURCE 1
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include "kerncompat.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "print-tree.h"
+#include "transaction.h"
+#include "list.h"
+#include "version.h"
+#include "utils.h"
+
+static void print_usage(void)
+{
+	fprintf(stderr, "usage: btrfs-zero-log dev\n");
+	fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
+	exit(1);
+}
+
+int main(int ac, char **av)
+{
+	struct btrfs_root *root;
+	int ret;
+
+	if (ac != 2)
+		print_usage();
+
+	radix_tree_init();
+
+	if((ret = check_mounted(av[1])) < 0) {
+		fprintf(stderr, "Could not check mount status: %s\n", strerror(ret));
+		return ret;
+	} else if(ret) {
+		fprintf(stderr, "%s is currently mounted. Aborting.\n", av[1]);
+		return -EBUSY;
+	}
+
+	root = open_ctree(av[1], 0, 1);
+
+	if (root == NULL)
+		return 1;
+
+	btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
+	btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
+	close_ctree(root);
+	return ret;
+}
-- 
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