Btrfs: add btrfs-debug-tree -b <block number> to print a single block

debug-tree.c

@@ -116,19 +116,23 @@ int main(int ac, char **av)
 	int ret;
 	int slot;
 	int extent_only = 0;
+	u64 block_only = 0;
 	struct btrfs_root *tree_root_scan;
 
 	radix_tree_init();
 
 	while(1) {
 		int c;
-		c = getopt(ac, av, "e");
+		c = getopt(ac, av, "eb:");
 		if (c < 0)
 			break;
 		switch(c) {
 			case 'e':
 				extent_only = 1;
 				break;
+			case 'b':
+				block_only = atoll(optarg);
+				break;
 			default:
 				print_usage();
 		}
@@ -142,14 +146,37 @@ int main(int ac, char **av)
 		fprintf(stderr, "unable to open %s\n", av[optind]);
 		exit(1);
 	}
+	if (block_only) {
+		leaf = read_tree_block(root,
+				      block_only,
+				      root->leafsize, 0);
+
+		if (leaf && btrfs_header_level(leaf) != 0) {
+			free_extent_buffer(leaf);
+			leaf = NULL;
+		}
+
+		if (!leaf) {
+			leaf = read_tree_block(root,
+					      block_only,
+					      root->nodesize, 0);
+		}
+		if (!leaf) {
+			fprintf(stderr, "failed to read %llu\n", block_only);
+			return 0;
+		}
+		btrfs_print_tree(root, leaf, 0);
+		return 0;
+	}
+
 	if (!extent_only) {
 		printf("root tree\n");
 		btrfs_print_tree(root->fs_info->tree_root,
-				 root->fs_info->tree_root->node);
+				 root->fs_info->tree_root->node, 1);
 
 		printf("chunk tree\n");
 		btrfs_print_tree(root->fs_info->chunk_root,
-				 root->fs_info->chunk_root->node);
+				 root->fs_info->chunk_root->node, 1);
 	}
 	tree_root_scan = root->fs_info->tree_root;
 
@@ -260,7 +287,7 @@ again:
 				printf(" tree ");
 				btrfs_print_key(&disk_key);
 				printf(" \n");
-				btrfs_print_tree(tree_root_scan, buf);
+				btrfs_print_tree(tree_root_scan, buf, 1);
 			} else if (extent_only && !skip) {
 				print_extents(tree_root_scan, buf);
 			}

dir-test.c

@@ -485,7 +485,7 @@ int main(int ac, char **av)
 			if (ret) {
 				fprintf(stderr, "op %d failed %d:%d\n",
 					op, i, iterations);
-				btrfs_print_tree(root, root->node);
+				btrfs_print_tree(root, root->node, 1);
 				fprintf(stderr, "op %d failed %d:%d\n",
 					op, i, iterations);
 				err = ret;

print-tree.c

@@ -607,7 +607,7 @@ void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l)
 	}
 }
 
-void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *eb)
+void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *eb, int follow)
 {
 	int i;
 	u32 nr;
@@ -643,6 +643,9 @@ void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *eb)
 		       (unsigned long long)btrfs_node_ptr_generation(eb, i));
 		fflush(stdout);
 	}
+	if (!follow)
+		return;
+
 	for (i = 0; i < nr; i++) {
 		struct extent_buffer *next = read_tree_block(root,
 					     btrfs_node_blockptr(eb, i),
@@ -660,8 +663,7 @@ void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *eb)
 		if (btrfs_header_level(next) !=
 			btrfs_header_level(eb) - 1)
 			BUG();
-		btrfs_print_tree(root, next);
+		btrfs_print_tree(root, next, 1);
 		free_extent_buffer(next);
 	}
 }
-

print-tree.h

@@ -19,6 +19,6 @@
 #ifndef __PRINT_TREE_
 #define __PRINT_TREE_
 void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l);
-void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *t);
+void btrfs_print_tree(struct btrfs_root *root, struct extent_buffer *t, int follow);
 void btrfs_print_key(struct btrfs_disk_key *disk_key);
 #endif

quick-test.c

@@ -85,7 +85,7 @@ int main(int ac, char **av) {
 			fprintf(stderr, "search %d:%d\n", num, i);
 		ret = btrfs_search_slot(NULL, root, &ins, &path, 0, 0);
 		if (ret) {
-			btrfs_print_tree(root, root->node);
+			btrfs_print_tree(root, root->node, 1);
 			printf("unable to find %d\n", num);
 			exit(1);
 		}
@@ -148,7 +148,7 @@ int main(int ac, char **av) {
 			fprintf(stderr, "search %d:%d\n", num, i);
 		ret = btrfs_search_slot(NULL, root, &ins, &path, 0, 0);
 		if (ret) {
-			btrfs_print_tree(root, root->node);
+			btrfs_print_tree(root, root->node, 1);
 			printf("unable to find %d\n", num);
 			exit(1);
 		}
@@ -196,7 +196,7 @@ int main(int ac, char **av) {
 	btrfs_commit_transaction(trans, root);
 	printf("tree size is now %d\n", tree_size);
 	printf("root %p commit root %p\n", root->node, root->commit_root);
-	btrfs_print_tree(root, root->node);
+	btrfs_print_tree(root, root->node, 1);
 	close_ctree(root);
 	return 0;
 }

random-test.c

@@ -404,7 +404,7 @@ int main(int ac, char **av)
 			if (ret) {
 				fprintf(stderr, "op %d failed %d:%d\n",
 					op, i, iterations);
-				btrfs_print_tree(root, root->node);
+				btrfs_print_tree(root, root->node, 1);
 				fprintf(stderr, "op %d failed %d:%d\n",
 					op, i, iterations);
 				err = ret;