zpool import hangs when out of space - Was: zfs pool import hangs on [tx->tx_sync_done_cv]

[K. Macy]

>> Thank you both for analysis and effort!
>>
>> I can't rule out the possibility that my main system pool
>> on a SSD was low on space at some point in time, but the
>> three 4 GiB cloned pools (sys1boot and its brothers) were all
>> created as a zfs send / receive copies of the main / (root)
>> file system and I haven't noticed anything unusual during
>> syncing. This syncing was done manually (using zxfer) and
>> independently from the upgrade on the system - on a steady/quiet
>> system, when the source file system definitely had sufficient
>> free space.
>>
>> The source file system now shows 1.2 GiB of usage shown
>> by df:
>>   shiny/ROOT  61758388  1271620  60486768  2%  /
>> Seems unlikely that the 1.2 GiB has grown to 4 GiB space
>> on a cloned filesystem.
>>
>> Will try to import the main two pools after re-creating
>> a sane boot pool...
>
>
> Yer zfs list only shows around 2-3GB used too but zpool list
> shows the pool is out of space. Cant rule out an accounting
> issue though.
>

What is using the extra space in the pool? Is there an unmounted
dataset or snapshot? Do you know how to easily tell? Unlike txg and
zio processing I don't have the luxury of having just read that part
of the codebase.

Thanks.