Arch Linux

KenMacD

Member

Registered: 2014-01-06

Posts: 21

btrfs issues with 3.14

I'm starting this thread for discussions around btrfs issues in 3.14 on the off chance I'm not the only one seeing this.

Since the kernel update to 3.14 I've been having issues with the /home partition and random processes hanging.

I'm running btrfs -> dmcrypt -> lvm2 -> SSD, and the issues reoccur within a week of rebuilding down to the lvm level.

The issues show up in the logs with something blocking for more than 120 seconds. Ex:

INFO: task btrfs-flush_del:470 blocked for more than 120 seconds.
      Tainted: G           O 3.14.1-1-ARCH #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
btrfs-flush_del D ffff8800689c2e58     0   470      2 0x00000000
 ffff88024e6e9d90 0000000000000046 ffff88024e730000 ffff88024e6e9fd8
 00000000000142c0 00000000000142c0 ffff88024e730000 ffff88024e6e9cd8
 ffffffff81095535 ffff88009bfc09d0 ffff88009bfc09d0 ffff88024e6e9d20
Call Trace:
 [<ffffffff81095535>] ? check_preempt_curr+0x85/0xa0
 [<ffffffff8109205b>] ? ttwu_stat+0x9b/0x110
 [<ffffffff8107279b>] ? lock_timer_base.isra.35+0x2b/0x50
 [<ffffffff8107287f>] ? try_to_del_timer_sync+0x4f/0x70
 [<ffffffff814d7eb9>] schedule+0x29/0x70
 [<ffffffffa04d3efd>] btrfs_start_ordered_extent+0x6d/0x120 [btrfs]
 [<ffffffff810aa350>] ? __wake_up_sync+0x20/0x20
 [<ffffffffa04d3fd5>] btrfs_run_ordered_extent_work+0x25/0x40 [btrfs]
 [<ffffffffa04e8cde>] worker_loop+0x14e/0x560 [btrfs]
 [<ffffffff810a9c68>] ? __wake_up_common+0x58/0x90
 [<ffffffffa04e8b90>] ? btrfs_queue_worker+0x310/0x310 [btrfs]
 [<ffffffff810872a2>] kthread+0xd2/0xf0
 [<ffffffff810871d0>] ? kthread_create_on_node+0x180/0x180
 [<ffffffff814e2ffc>] ret_from_fork+0x7c/0xb0
 [<ffffffff810871d0>] ? kthread_create_on_node+0x180/0x180

Although I see other processes like systemd-sleep, mozStorage, and BrowserBlocking also hang with btrfs in the stack trace.

When this occurs the process can not be killed and the only way to get rid of it is with a hard reboot.

'btrfs check' also shows errors, even on a week-old filesystem:

checking extents
checking free space cache
Wanted bytes 45056, found 32768 for off 63805808640
Wanted bytes 111190016, found 32768 for off 63805808640
cache appears valid but isnt 62843256832
Checking filesystem on //dev/mapper/home
UUID: 9a60a25f-eeb4-494c-b1af-ebd8e4f79b6b
found 13672418478 bytes used err is -22
total csum bytes: 72089212
total tree bytes: 906100736
total fs tree bytes: 808370176
total extent tree bytes: 18153472
btree space waste bytes: 116247440
file data blocks allocated: 101046853632
 referenced 73680674816
Btrfs v3.14.1

I've reported the bugs upstream as bugs 75181 and 75191 and posted to the linux-btrfs mailing list.

I was instructed to try the mainline kernel, so I've installed the linux-mainline package arch.miffe.org and will report any new issues.

If anyone has seem similar issues, or has any other purposed solutions please let me know.

ratcheer

Member

Registered: 2011-10-09

Posts: 924

Re: btrfs issues with 3.14

I can say that I installed the latest Arch to btrfs, yesterday, and everything seems to be working flawlessly. But my configuration is nowhere near as complex as yours, just btrfs RAID-0 on two SATA-III drives.

Tim

WorMzy

Administrator

From: Scotland

Registered: 2010-06-16

Posts: 13,582

Website

Re: btrfs issues with 3.14

Please don't empty post, Ratcheer.

@KenMacD: I just saw a message on the mailing lists about this (or a similar problem): http://www.mail-archive.com/linux-btrfs … 33795.html

From Chris' response, it appears that this should be fixed in the next 3.15 rc.

---

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Making lemonade from lemons since 2015.

KenMacD

Member

Registered: 2014-01-06

Posts: 21

Re: btrfs issues with 3.14

Thanks. I spoke with the mailing list and I think it's an issue when the filesystem starts to fill up. There's discussion around a patch at https://patchwork.kernel.org/patch/4139971/ so hopefully something will be merged in soon.

I moved a lot of data off to a external drive and haven't seen it reoccur, so I think that's a workaround for anyone else experiencing this issue.

KenMacD

Member

Registered: 2014-01-06

Posts: 21

Re: btrfs issues with 3.14

Thanks WorMzy, I didn't see your post while I was writing mine. Good to hear the fixes are making it into the next RC. I'll copy the files back once it's released and report back as to if it seems fixed.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: btrfs issues with 3.14

miffe provides a user repo which includes binary packages of his linux-mainline.  He seems to be pretty good about keeping pace with the rc releases (so is at 3.15rc5 right now).  Maybe you want to give that a whirl.

http://arch.miffe.org/