Btrfs-progs: make btrfs-image copy the tree logs if they exist

Currently btrfs-image doesn't copy the tree logs, which doesn't help me when
we're trying to debug log replay bugs.  Since we don't have entries in the
extent root for the blocks we have to walk down all of the trees in order to
copy them.  With this patch I can image a file system with a tree log and it
works fine.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/btrfs-image.c b/btrfs-image.c
index ad4f94c2..0d58bd04 100644
--- a/btrfs-image.c
+++ b/btrfs-image.c
@@ -532,6 +532,84 @@ static int is_tree_block(struct btrfs_root *extent_root,
 }
 #endif
 
+static int copy_log_blocks(struct btrfs_root *root, struct extent_buffer *eb,
+			   struct metadump_struct *metadump,
+			   int log_root_tree)
+{
+	struct extent_buffer *tmp;
+	struct btrfs_root_item *ri;
+	struct btrfs_key key;
+	u64 bytenr;
+	int level;
+	int nritems = 0;
+	int i = 0;
+	int ret;
+
+	ret = add_metadata(btrfs_header_bytenr(eb), root->leafsize, metadump);
+	if (ret) {
+		fprintf(stderr, "Error adding metadata block\n");
+		return ret;
+	}
+
+	if (btrfs_header_level(eb) == 0 && !log_root_tree)
+		return 0;
+
+	level = btrfs_header_level(eb);
+	nritems = btrfs_header_nritems(eb);
+	for (i = 0; i < nritems; i++) {
+		if (level == 0) {
+			btrfs_item_key_to_cpu(eb, &key, i);
+			if (key.type != BTRFS_ROOT_ITEM_KEY)
+				continue;
+			ri = btrfs_item_ptr(eb, i, struct btrfs_root_item);
+			bytenr = btrfs_disk_root_bytenr(eb, ri);
+			tmp = read_tree_block(root, bytenr, root->leafsize, 0);
+			if (!tmp) {
+				fprintf(stderr,
+					"Error reading log root block\n");
+				return -EIO;
+			}
+			ret = copy_log_blocks(root, tmp, metadump, 0);
+			free_extent_buffer(tmp);
+			if (ret)
+				return ret;
+		} else {
+			bytenr = btrfs_node_blockptr(eb, i);
+			tmp = read_tree_block(root, bytenr, root->leafsize, 0);
+			if (!tmp) {
+				fprintf(stderr, "Error reading log block\n");
+				return -EIO;
+			}
+			ret = copy_log_blocks(root, tmp, metadump,
+					      log_root_tree);
+			free_extent_buffer(tmp);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int copy_log_trees(struct btrfs_root *root,
+			  struct metadump_struct *metadump,
+			  struct btrfs_path *path)
+{
+	u64 blocknr = btrfs_super_log_root(root->fs_info->super_copy);
+
+	if (blocknr == 0)
+		return 0;
+
+	if (!root->fs_info->log_root_tree ||
+	    !root->fs_info->log_root_tree->node) {
+		fprintf(stderr, "Error copying tree log, it wasn't setup\n");
+		return -EIO;
+	}
+
+	return copy_log_blocks(root, root->fs_info->log_root_tree->node,
+			       metadump, 1);
+}
+
 static int create_metadump(const char *input, FILE *out, int num_threads,
 			   int compress_level)
 {
@@ -658,6 +736,9 @@ static int create_metadump(const char *input, FILE *out, int num_threads,
 		bytenr += num_bytes;
 	}
 
+	ret = copy_log_trees(root, &metadump, path);
+	if (ret)
+		err = ret;
 out:
 	ret = flush_pending(&metadump, 1);
 	if (ret) {