btrfs: unfold transaction aborts in btrfs_finish_one_ordered()

btrfs: unfold transaction aborts in btrfs_finish_one_ordered()

We have a single transaction abort that can be caused either by a failure
from a call to btrfs_mark_extent_written(), if we are dealing with a
write to a prealloc extent, or otherwise from a call to
insert_ordered_extent_file_extent(). So when the transaction abort happens
we can not know for sure which case failed. Unfold the aborts so that it's
clear in case of a failure.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>