Re: [PATCH] btrfs: extent-tree.c: Remove redundant variable from btrfs_cross_ref_exist()

[Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>]

On 2018/09/07 0:57, David Sterba wrote:
> On Thu, Aug 30, 2018 at 10:59:16AM +0900, Misono Tomohiro wrote:
>> Since commit d7df2c796d7e ("Btrfs attach delayed ref updates to
>> delayed ref heads"), check_delaed_ref() won't return -ENOENT.
>>
>> In btrfs_cross_ref_exist(), two variable 'ret' and 'ret2' is
>> originally used to handle -ENOENT error case.
>>
>> Since the code is not needed anymore, let's just remove 'ret2'.
> 
> Good cleanup and the patch would be ok as-is. I've noticed that
> check_delayed_ref now returns only two values so it might make sense to
> turn it to bool and update the name of check_delayed_ref to make it
> clear what the return value means in the loop.

check_delaed_ref()'s return value is:
 0       ... no cross ref found in delayed ref
 1       ... cross ref found in delayed ref
 -EAGAIN ... cannot acquire lock and try again later

so I don't think we can convert it to bool directly or
do you mean we should handle -EAGAIN in check_delayed_ref()?

> The concern here is that adding another error code in check_delayed_ref
> in the future will not be caught in btrfs_cross_ref_exist. Adding an
> assert filtering only EAGAIN would be sufficient as this might miss the
> extra value in case it'd be an uncommon case.