From 0c8b978881f8f5d2b15b7bf2ec5621500ec3858a Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 11 May 2015 16:08:47 +0800 Subject: btrfs-progs: Introduce change_header_uuid function This function is used to change fsid and chunk_tree_uuid of a node/leaf. The function does it without transaction protection. This is the basis of offline uuid change. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- btrfstune.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'btrfstune.c') diff --git a/btrfstune.c b/btrfstune.c index 808466f9..92837e6f 100644 --- a/btrfstune.c +++ b/btrfstune.c @@ -98,6 +98,38 @@ static int enable_skinny_metadata(struct btrfs_root *root) return 0; } +static int change_header_uuid(struct btrfs_root *root, struct extent_buffer *eb) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + int same_fsid = 1; + int same_chunk_tree_uuid = 1; + int ret; + + /* Check for whether we need to change fs/chunk id */ + if (!fs_info->new_fsid && !fs_info->new_chunk_tree_uuid) + return 0; + if (fs_info->new_fsid) + same_fsid = !memcmp_extent_buffer(eb, fs_info->new_fsid, + btrfs_header_fsid(), BTRFS_FSID_SIZE); + if (fs_info->new_chunk_tree_uuid) + same_chunk_tree_uuid = + !memcmp_extent_buffer(eb, fs_info->new_chunk_tree_uuid, + btrfs_header_chunk_tree_uuid(eb), + BTRFS_UUID_SIZE); + if (same_fsid && same_chunk_tree_uuid) + return 0; + if (!same_fsid) + write_extent_buffer(eb, fs_info->new_fsid, btrfs_header_fsid(), + BTRFS_FSID_SIZE); + if (!same_chunk_tree_uuid) + write_extent_buffer(eb, fs_info->new_chunk_tree_uuid, + btrfs_header_chunk_tree_uuid(eb), + BTRFS_UUID_SIZE); + ret = write_tree_block(NULL, root, eb); + + return ret; +} + static void print_usage(void) { fprintf(stderr, "usage: btrfstune [options] device\n"); -- cgit v1.2.3