When flushing space we join a transaction to flush delayed items and
delayed references, in order to try to release space. However using
btrfs_join_transaction() not only joins an existing transaction as well
as it starts a new transaction if there is none open. If there is no
transaction open, we don't have neither delayed items nor delayed
references, so creating a new transaction is a waste of time, IO and
creates an unnecessary rotation of the backup roots without gaining any
benefits (including releasing space).
So use btrfs_join_transaction_nostart() when attempting to flush delayed
items and references.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
else
nr = -1;
- trans = btrfs_join_transaction(root);
+ trans = btrfs_join_transaction_nostart(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
+ if (ret == -ENOENT)
+ ret = 0;
break;
}
ret = btrfs_run_delayed_items_nr(trans, nr);
break;
case FLUSH_DELAYED_REFS_NR:
case FLUSH_DELAYED_REFS:
- trans = btrfs_join_transaction(root);
+ trans = btrfs_join_transaction_nostart(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
+ if (ret == -ENOENT)
+ ret = 0;
break;
}
if (state == FLUSH_DELAYED_REFS_NR)