File 0006-Btrfs-progs-fsck-clear-out-log-tree-in-repair-mode.patch of Package btrfsprogs

From 3ecff1d8f1eaa5e0d065c439cf72032dd01da751 Mon Sep 17 00:00:00 2001
From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Date: Thu, 24 Apr 2014 11:19:16 +0800
Subject: [PATCH 13/42] Btrfs-progs: fsck: clear out log tree in repair mode

Repair mode will commit transaction which will make us
fail to load log tree anymore.

Give a warning to common users, if they really want to
coninue, we will clear out log tree.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
---
 cmds-check.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

Index: btrfs-progs-v3.16/cmds-check.c
===================================================================
--- btrfs-progs-v3.16.orig/cmds-check.c
+++ btrfs-progs-v3.16/cmds-check.c
@@ -6538,6 +6538,22 @@ out:
 	return ret;
 }
 
+static int zero_log_tree(struct btrfs_root *root)
+{
+	struct btrfs_trans_handle *trans;
+	int ret;
+
+	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		return ret;
+	}
+	btrfs_set_super_log_root(root->fs_info->super_copy, 0);
+	btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
+	ret = btrfs_commit_transaction(trans, root);
+	return ret;
+}
+
 static struct option long_options[] = {
 	{ "super", 1, NULL, 's' },
 	{ "repair", 0, NULL, 0 },
@@ -6657,6 +6673,23 @@ int cmd_check(int argc, char **argv)
 	}
 
 	root = info->fs_root;
+	/*
+	 * repair mode will force us to commit transaction which
+	 * will make us fail to load log tree when mounting.
+	 */
+	if (repair && btrfs_super_log_root(info->super_copy)) {
+		ret = ask_user("repair mode will force to clear out log tree, Are you sure?");
+		if (!ret) {
+			ret = 1;
+			goto close_out;
+		}
+		ret = zero_log_tree(root);
+		if (ret) {
+			fprintf(stderr, "fail to zero log tree\n");
+			goto close_out;
+		}
+	}
+
 	uuid_unparse(info->super_copy->fsid, uuidbuf);
 	if (qgroup_report) {
 		printf("Print quota groups for %s\nUUID: %s\n", argv[optind],