On 2015-06-17 11:40, Christian wrote:
> On 06/17/2015 11:28 AM, Chris Murphy wrote:
>
>>>
>>> However, fstrim still gives me "0 B (0 bytes) trimmed, so that may be
>>> another problem. Is there a way to check if trim works?
>>
>> That sounds like maybe your SSD is blacklisted for trim, is all I can
>> think of. So trim shouldn't be the cause of the problem if it's being
>> blacklisted. The recent problems appear to be around newer SSDs that
>> support queue trim and newer kernels that issue queued trim. There
>> have been some patches related to trim to the kernel, but the
>> existence of blacklisting and claims of bugs in firmware make it
>> difficult to test and isolate.
>>
>> http://techreport.com/news/28473/some-samsung-ssds-may-suffer-from-a-buggy-trim-implementation
>>
>>
> This is an Intel SSD in a Lenovo Thinkpad X1 Carbon. Trim worked until a
> few weeks ago and still works for my small ext4 boot partition (just ran
> it to check). I will keep looking for a solution. Thanks!
>
I'm seeing the same issue here, but with a Crucial brand SSD.  Somewhat 
interestingly, I don't see any issues like this with BTRFS on top of 
LVM's thin-provisioning volumes, or with any other filesystems, so I 
think it has something to do with how BTRFS is reporting unused space or 
how it is submitting the discard requests.