static int update_cowonly_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_root_bytenr;
u64 old_root_used;
struct btrfs_root *tree_root = root->fs_info->tree_root;
old_root_used = btrfs_root_used(&root->root_item);
btrfs_write_dirty_block_groups(trans, root);
while (1) {
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
if (old_root_bytenr == root->node->start &&
old_root_used == btrfs_root_used(&root->root_item))
break;
btrfs_set_root_node(&root->root_item, root->node);
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
&root->root_item);
BUG_ON(ret);
old_root_used = btrfs_root_used(&root->root_item);
ret = btrfs_write_dirty_block_groups(trans, root);
BUG_ON(ret);
}
if (root != root->fs_info->extent_root)
switch_commit_root(root);
return 0;
}
static void print_root(struct extent_buffer *leaf, int slot)
{
struct btrfs_root_item *ri;
struct btrfs_root_item root_item;
int len;
char uuid_str[BTRFS_UUID_UNPARSED_SIZE];
char flags_str[32] = {0};
struct btrfs_key drop_key;
ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
len = btrfs_item_size_nr(leaf, slot);
memset(&root_item, 0, sizeof(root_item));
read_extent_buffer(leaf, &root_item, (unsigned long)ri, len);
root_flags_to_str(btrfs_root_flags(&root_item), flags_str);
printf("\t\tgeneration %llu root_dirid %llu bytenr %llu level %hhu refs %u\n",
(unsigned long long)btrfs_root_generation(&root_item),
(unsigned long long)btrfs_root_dirid(&root_item),
(unsigned long long)btrfs_root_bytenr(&root_item),
btrfs_root_level(&root_item),
btrfs_root_refs(&root_item));
printf("\t\tlastsnap %llu byte_limit %llu bytes_used %llu flags 0x%llx(%s)\n",
(unsigned long long)btrfs_root_last_snapshot(&root_item),
(unsigned long long)btrfs_root_limit(&root_item),
(unsigned long long)btrfs_root_used(&root_item),
(unsigned long long)btrfs_root_flags(&root_item),
flags_str);
if (root_item.generation == root_item.generation_v2) {
uuid_unparse(root_item.uuid, uuid_str);
printf("\t\tuuid %s\n", uuid_str);
if (!empty_uuid(root_item.parent_uuid)) {
uuid_unparse(root_item.parent_uuid, uuid_str);
printf("\t\tparent_uuid %s\n", uuid_str);
}
if (!empty_uuid(root_item.received_uuid)) {
uuid_unparse(root_item.received_uuid, uuid_str);
printf("\t\treceived_uuid %s\n", uuid_str);
}
if (root_item.ctransid) {
printf("\t\tctransid %llu otransid %llu stransid %llu rtransid %llu\n",
btrfs_root_ctransid(&root_item),
btrfs_root_otransid(&root_item),
btrfs_root_stransid(&root_item),
btrfs_root_rtransid(&root_item));
}
}
btrfs_disk_key_to_cpu(&drop_key, &root_item.drop_progress);
printf("\t\tdrop ");
btrfs_print_key(&root_item.drop_progress);
printf(" level %hhu\n", root_item.drop_level);
}
static ssize_t root_blocks_used_show(struct btrfs_root *root, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%llu\n",
(unsigned long long)btrfs_root_used(&root->root_item));
}
/*
* Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
* all of them
*/
static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
struct list_head *list)
{
struct btrfs_dirty_root *dirty;
struct btrfs_trans_handle *trans;
unsigned long nr;
u64 num_bytes;
u64 bytes_used;
u64 max_useless;
int ret = 0;
int err;
while (!list_empty(list)) {
struct btrfs_root *root;
dirty = list_entry(list->prev, struct btrfs_dirty_root, list);
list_del_init(&dirty->list);
num_bytes = btrfs_root_used(&dirty->root->root_item);
root = dirty->latest_root;
atomic_inc(&root->fs_info->throttles);
while (1) {
/*
* we don't want to jump in and create a bunch of
* delayed refs if the transaction is starting to close
*/
wait_transaction_pre_flush(tree_root->fs_info);
trans = btrfs_start_transaction(tree_root, 1);
/*
* we've joined a transaction, make sure it isn't
* closing right now
*/
if (trans->transaction->delayed_refs.flushing) {
btrfs_end_transaction(trans, tree_root);
continue;
}
mutex_lock(&root->fs_info->drop_mutex);
ret = btrfs_drop_snapshot(trans, dirty->root);
if (ret != -EAGAIN)
break;
mutex_unlock(&root->fs_info->drop_mutex);
err = btrfs_update_root(trans,
tree_root,
&dirty->root->root_key,
&dirty->root->root_item);
if (err)
ret = err;
nr = trans->blocks_used;
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
btrfs_btree_balance_dirty(tree_root, nr);
cond_resched();
}
BUG_ON(ret);
atomic_dec(&root->fs_info->throttles);
wake_up(&root->fs_info->transaction_throttle);
num_bytes -= btrfs_root_used(&dirty->root->root_item);
bytes_used = btrfs_root_used(&root->root_item);
if (num_bytes) {
mutex_lock(&root->fs_info->trans_mutex);
btrfs_record_root_in_trans(root);
mutex_unlock(&root->fs_info->trans_mutex);
btrfs_set_root_used(&root->root_item,
bytes_used - num_bytes);
}
ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
if (ret) {
BUG();
break;
}
mutex_unlock(&root->fs_info->drop_mutex);
spin_lock(&root->list_lock);
list_del_init(&dirty->root->dead_list);
if (!list_empty(&root->dead_list)) {
struct btrfs_root *oldest;
oldest = list_entry(root->dead_list.prev,
struct btrfs_root, dead_list);
max_useless = oldest->root_key.offset - 1;
} else {
max_useless = root->root_key.offset - 1;
}
spin_unlock(&root->list_lock);
nr = trans->blocks_used;
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
ret = btrfs_remove_leaf_refs(root, max_useless, 0);
BUG_ON(ret);
free_extent_buffer(dirty->root->node);
kfree(dirty->root);
kfree(dirty);
btrfs_btree_balance_dirty(tree_root, nr);
cond_resched();
}
