From 605621993d414e0779d1d47426d2f1524de3b214 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 11 May 2015 16:08:48 +0800 Subject: btrfs-progs: Introduce change_extents_uuid function This is the function which iterates all metadata extents and changes their fsid. This function also does it without transaction. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- btrfstune.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/btrfstune.c b/btrfstune.c index 92837e6f..b8900113 100644 --- a/btrfstune.c +++ b/btrfstune.c @@ -130,6 +130,74 @@ static int change_header_uuid(struct btrfs_root *root, struct extent_buffer *eb) return ret; } +static int change_extents_uuid(struct btrfs_fs_info *fs_info) +{ + struct btrfs_root *root = fs_info->extent_root; + struct btrfs_path *path; + struct btrfs_key key = {0, 0, 0}; + int ret = 0; + + if (!fs_info->new_fsid && !fs_info->new_chunk_tree_uuid) + return 0; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + /* + * Here we don't use transaction as it will takes a lot of reserve + * space, and that will make a near-full btrfs unable to change uuid + */ + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + + while (1) { + struct btrfs_extent_item *ei; + struct extent_buffer *eb; + u64 flags; + u64 bytenr; + + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + if (key.type != BTRFS_EXTENT_ITEM_KEY && + key.type != BTRFS_METADATA_ITEM_KEY) + goto next; + ei = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_extent_item); + flags = btrfs_extent_flags(path->nodes[0], ei); + if (!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) + goto next; + + bytenr = key.objectid; + eb = read_tree_block(root, bytenr, root->nodesize, 0); + if (IS_ERR(eb)) { + fprintf(stderr, "Failed to read tree block: %llu\n", + bytenr); + ret = PTR_ERR(eb); + goto out; + } + ret = change_header_uuid(root, eb); + free_extent_buffer(eb); + if (ret < 0) { + fprintf(stderr, "Failed to change uuid of tree block: %llu\n", + bytenr); + goto out; + } +next: + ret = btrfs_next_item(root, path); + if (ret < 0) + goto out; + if (ret > 0) { + ret = 0; + goto out; + } + } + +out: + btrfs_free_path(path); + return ret; +} + static void print_usage(void) { fprintf(stderr, "usage: btrfstune [options] device\n"); -- cgit v1.2.3