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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 <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
master
Qu Wenruo 2015-05-11 16:08:48 +08:00 committed by David Sterba
parent 0c8b978881
commit 605621993d
1 changed files with 68 additions and 0 deletions
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68
btrfstune.c
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@ -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");