btrfsck: add --init-csum-tree to replace the csum root with an empty one

This will effectively delete all of your crcs, but at least you'll
be able to mount the FS with nodatasum.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 22 insertions, 5 deletions

diff --git a/btrfsck.c b/btrfsck.c
index a5dbbee1..606ebfca 100644
--- a/btrfsck.c
+++ b/btrfsck.c
@@ -3171,6 +3171,7 @@ static void print_usage(void)
 static struct option long_options[] = {
 	{ "super", 1, NULL, 's' },
 	{ "repair", 0, NULL, 0 },
+	{ "init-csum-tree", 0, NULL, 0 },
 	{ 0, 0, 0, 0}
 };
 
@@ -3185,6 +3186,8 @@ int main(int ac, char **av)
 	int num;
 	int repair = 0;
 	int option_index = 0;
+	int init_csum_tree = 0;
+	int rw = 0;
 
 	while(1) {
 		int c;
@@ -3205,6 +3208,11 @@ int main(int ac, char **av)
 		if (option_index == 1) {
 			printf("enabling repair mode\n");
 			repair = 1;
+			rw = 1;
+		} else if (option_index == 2) {
+			printf("Creating a new CRC tree\n");
+			init_csum_tree = 1;
+			rw = 1;
 		}
 
 	}
@@ -3224,7 +3232,7 @@ int main(int ac, char **av)
 		return -EBUSY;
 	}
 
-	info = open_ctree_fs_info(av[optind], bytenr, repair, 1);
+	info = open_ctree_fs_info(av[optind], bytenr, rw, 1);
 
 	if (info == NULL)
 		return 1;
@@ -3240,9 +3248,19 @@ int main(int ac, char **av)
 	root = info->fs_root;
 
 	fprintf(stderr, "checking extents\n");
-	if (repair)
+	if (rw)
 		trans = btrfs_start_transaction(root, 1);
 
+	if (init_csum_tree) {
+		fprintf(stderr, "Reinit crc root\n");
+		ret = btrfs_fsck_reinit_root(trans, info->csum_root);
+		if (ret) {
+			fprintf(stderr, "crc root initialization failed\n");
+			return -EIO;
+		}
+		goto out;
+	}
+
 	ret = check_extents(trans, root, repair);
 	if (ret)
 		goto out;
@@ -3259,15 +3277,14 @@ int main(int ac, char **av)
 	ret = check_root_refs(root, &root_cache);
 out:
 	free_root_recs(&root_cache);
-	if (repair) {
+	if (rw) {
 		ret = btrfs_commit_transaction(trans, root);
 		if (ret)
 			exit(1);
 	}
 	close_ctree(root);
 
-	if (found_old_backref) {
-		/*
+	if (found_old_backref) { /*
 		 * there was a disk format change when mixed
 		 * backref was in testing tree. The old format
 		 * existed about one week.