Sorry about the late reply!!
On 03/10/2015 04:41 PM, Qu Wenruo wrote:
-------- Original Message --------
Subject: Re: Quota limit question
From: Christian Robottom Reis <k...@canonical.com>
To: Duncan <1i5t5.dun...@cox.net>
Date: 2015年03月07日 05:44
Just as a follow-up, I upgraded btrfs-tools and the kernel again. I
currently have a filesystem which reports 1G exclusive use:
root@riff# btrfs qg show -r -e /var -p -c
qgroupid rfer excl max_rfer max_excl parent
child
-------- ---- ---- -------- -------- ------
-----
0/261 1.52GiB 1.01GiB 0.00B 100.00GiB --- ---
It's recommended to sync the btrfs before 'qg show' command, since
quota tree is not updated until commit transaction.
Yes, sync is required be fore qg show now. There is no ioctl to get
qgroup info from kernel space,
so we have to read the data from disk then we have to do a sync before
we getting the correct information.
This filesystem reports over quota, and removing the quota fixes that:
root@riff# touch x
touch: cannot touch ‘x’: Disk quota exceeded
root@riff# btrfs qg limit -e
none 261 /var
root@riff# touch x
root@riff#
So at the moment quotas are pretty much unusable in kernel 3.18.6/tools
3.18.2, at least for my use case, and that's a bit surprising since
there isn't anything very interesting about it (other than it contains a
bunch of lxc-cloned rootfs).
Yes, Btrfs really has some problems, from yours to other annoying
incorrect values.
[Some guess]
For your case, I'm afraid your reserved space in your qgroup takes too
much space, and it's definitely a bug. Maybe some
btrfs_qgroup_reserve() leaking?
Agreed, there must be a reserve leaking in your use case. And I have posted
some patches about qgroup.reserved. some of them is about reserved leaking.
Could you try the tree :
btrfs:https://yangdongsh...@github.com/yangdongsheng/linux.git
qgroup_type
btrfs-progs:https://yangdongsh...@github.com/yangdongsheng/btrfs-progs.git
qgroup_type
It could be working better but I can not guarantee your problem here
will be solved by it.
[Reproducer]
Would you please describe your workload? Or some easy-to-reproduce
scripts?
[Image dump/debug tree]
Another one which may help is your btrfs-debug-tree output on your
quota tree.
You can dump it by "btrfs-debug-tree -t 8 <DEVICE>".
Or full disk metadata dump by "btrfs-image -c9 <DEVICE>"
A reproducer is great for investigation. "btrfs-debug-tree" is important
to us.
Thanx
Yang
Thanks,
Qu
I've proactively added Yang who has submitted a few patches on quota
checking recently just to let me know if he thinks that this should be
fixed with a trunk kernel, or if he'd like to investigate or consider
this further. Thanks!
On Wed, Dec 24, 2014 at 03:52:41AM +0000, Duncan wrote:
Christian Robottom Reis posted on Tue, 23 Dec 2014 18:36:02 -0200 as
excerpted:
On Tue, Dec 16, 2014 at 11:15:37PM -0200, Christian Robottom Reis
wrote:
# btrfs qgroup limit 2000m 0/261 . && touch x touch: cannot
touch
‘x’: Disk quota exceeded
The strange thing is that it doesn't seem to be actually out of
space:
# btrfs qgroup show -p -r -e /var | grep 261
0/261 1111810048 391114752 2097152000 0 ---
Replying to myself as I had not yet been subscribed in time to
receive a
reply; I just upgraded to 3.18.1 and am seeing the same issue on the
same subvolume (and on no others).
Looking at the thread here on gmane.org (list2news and list2web
gateway),
it appears my reply was the only reply in any case, and it was
general as
I don't run quotas myself.
Basically I suggested upgrading, as the quota code as some rather huge
bugs in it (quotas could go seriously negative!) with the old versions
you were running. But you've upgraded at least the kernel now
(userspace
you didn't say).
Here's a link to the thread on the gmane web interface for
completeness,
but the above about covers my reply, as I said the only one until your
thread bump and my reply here, so there's not much new there unless
someone posts further followups to this thread...
http://comments.gmane.org/gmane.comp.file-systems.btrfs/41491
--
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman
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