Btrfsck: add the ability to prune corrupt extent allocation tree blocks

When we discover bad blocks in the extent allocation tree, repair can
now discard them and recreate the references from the rest of the trees.

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

1 files changed, 68 insertions, 3 deletions

diff --git a/btrfs-corrupt-block.c b/btrfs-corrupt-block.c
index 9ad3e05..980a006 100644
--- a/btrfs-corrupt-block.c
+++ b/btrfs-corrupt-block.c
@@ -93,6 +93,56 @@ static void print_usage(void)
 	exit(1);
 }
 
+static void corrupt_keys(struct btrfs_trans_handle *trans,
+			 struct btrfs_root *root,
+			 struct extent_buffer *eb)
+{
+	int slot;
+	int bad_slot;
+	int nr;
+	struct btrfs_disk_key bad_key;;
+
+	nr = btrfs_header_nritems(eb);
+	if (nr == 0)
+		return;
+
+	slot = rand() % nr;
+	bad_slot = rand() % nr;
+
+	if (bad_slot == slot)
+		return;
+
+	fprintf(stderr, "corrupting keys in block %llu slot %d swapping with %d\n",
+		(unsigned long long)eb->start, slot, bad_slot);
+
+	if (btrfs_header_level(eb) == 0) {
+		btrfs_item_key(eb, &bad_key, bad_slot);
+		btrfs_set_item_key(eb, &bad_key, slot);
+	} else {
+		btrfs_node_key(eb, &bad_key, bad_slot);
+		btrfs_set_node_key(eb, &bad_key, slot);
+	}
+	btrfs_mark_buffer_dirty(eb);
+	if (!trans) {
+		csum_tree_block(root, eb, 0);
+		write_extent_to_disk(eb);
+	}
+}
+
+
+static int corrupt_keys_in_block(struct btrfs_root *root, u64 bytenr)
+{
+	struct extent_buffer *eb;
+
+	eb = read_tree_block(root, bytenr, root->leafsize, 0);
+	if (!eb)
+		return -EIO;;
+
+	corrupt_keys(NULL, root, eb);
+	free_extent_buffer(eb);
+	return 0;
+}
+
 static int corrupt_extent(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root, u64 bytenr, int copy)
 {
@@ -192,6 +242,11 @@ static void btrfs_corrupt_extent_tree(struct btrfs_trans_handle *trans,
 	if (!eb)
 		return;
 
+	if ((rand() % 10) == 0) {
+		corrupt_keys(trans, root, eb);
+		return;
+	}
+
 	nr = btrfs_header_nritems(eb);
 	if (btrfs_is_leaf(eb)) {
 		btrfs_corrupt_extent_leaf(trans, root, eb);
@@ -222,6 +277,7 @@ static struct option long_options[] = {
 	{ "bytes", 1, NULL, 'b' },
 	{ "extent-record", 0, NULL, 'e' },
 	{ "extent-tree", 0, NULL, 'E' },
+	{ "keys", 0, NULL, 'k' },
 	{ 0, 0, 0, 0}
 };
 
@@ -239,12 +295,13 @@ int main(int ac, char **av)
 	u64 bytes = 4096;
 	int extent_rec = 0;
 	int extent_tree = 0;
+	int corrupt_block_keys = 0;
 
 	srand(128);
 
 	while(1) {
 		int c;
-		c = getopt_long(ac, av, "l:c:eE", long_options,
+		c = getopt_long(ac, av, "l:c:eEk", long_options,
 				&option_index);
 		if (c < 0)
 			break;
@@ -279,6 +336,9 @@ int main(int ac, char **av)
 			case 'E':
 				extent_tree = 1;
 				break;
+			case 'k':
+				corrupt_block_keys = 1;
+				break;
 			default:
 				print_usage();
 		}
@@ -324,8 +384,13 @@ int main(int ac, char **av)
 	bytes *= root->sectorsize;
 
 	while (bytes > 0) {
-		eb = debug_corrupt_block(root, logical, root->sectorsize, copy);
-		free_extent_buffer(eb);
+		if (corrupt_block_keys) {
+			corrupt_keys_in_block(root, logical);
+		} else {
+			eb = debug_corrupt_block(root, logical,
+						 root->sectorsize, copy);
+			free_extent_buffer(eb);
+		}
 		logical += root->sectorsize;
 		bytes -= root->sectorsize;
 	}