BTRFS BUG at insert_inline_extent_backref+0xe3/0xf0 while rebalancing

Hello,

Recently I added daily rebalancing to my cron.d (after finding myself in the no-space-situation), and not long after that, I found my PC had crashed over night. Having no sign in the logs anywhere (not even over network even though there should be) I had nothing to go on, but this night it crashed again after starting the rebalance, and this time there was some information on the kernel log.

Kernel version: 4.2.3 (package linux-image-4.2.0-1-amd64 version 4.2.3-1 from Debian Unstable)

The dump is available at:

http://www.modeemi.fi/~flux/btrfs/btrfs-BUG-2015-10-55.txt

The log is available as well (stripped some unrelated USB- and firewall logging, showing that last evening there was some kernel task hung for 120 seconds; but it's in another btrfs filesystem and is another story):

http://www.modeemi.fi/~flux/btrfs/btrfs-2015-10-55.txt

I'm not quite sure which of the btrfs balance commands caused the issue. But there is my script:

#!/bin/sh
fs="$1"
if [ -z "$fs" ]; then
echo usage: btrfs-balance / 0 1 5 10 20 50
exit 1
fi
fs="$1"
shift
for usage in d m; do for a in "$@"; do date; /bin/btrfs balance start "$fs" -v -${usage}usage=$a; done; done

And it was started at 07:30 with:

/usr/local/sbin/btrfs-balance / 0 1 2 5 10 20 30 50 70

I should add that the filesystem in question is backed by MD RAID10 and that is backed by four SSDs, so it's reasonably fast in IO, if that affects anything. There should have been no much competing IO at the time of the occurrence.

Before Duncan asks ;-), I only have a moderate number of subvolumes and snapshots, ie. one subvolume for each of /, /var/log/journal and /home, 24 snapshots of / and /home plus <10 snapshots of /.

Before that balance there was another balance on a another BTRFS RAID10, but given the time stamp I think I can easily say it wasn't the cause.

I don't really have other 'solutions' than disabling the rebalancing for the time being, and only use it as-needed as I had earlier done..

Cheers,

--
_____________________________________________________________________
/ __// /__ ____ __ http://www.modeemi.fi/~flux/\ \
/ /_ / // // /\ \/ / \ /
/_/ /_/ \___/ /_/\_\@modeemi.fi \/

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html

Quoted 49 lines

Hello,

Recently I added daily rebalancing to my cron.d (after finding myself in the no-space-situation), and not long after that, I found my PC had crashed over night. Having no sign in the logs anywhere (not even over network even though there should be) I had nothing to go on, but this night it crashed again after starting the rebalance, and this time there was some information on the kernel log.

Kernel version: 4.2.3 (package linux-image-4.2.0-1-amd64 version 4.2.3-1 from Debian Unstable)

The dump is available at:

http://www.modeemi.fi/~flux/btrfs/btrfs-BUG-2015-10-55.txt

The log is available as well (stripped some unrelated USB- and firewall logging, showing that last evening there was some kernel task hung for 120 seconds; but it's in another btrfs filesystem and is another story):

http://www.modeemi.fi/~flux/btrfs/btrfs-2015-10-55.txt

I'm not quite sure which of the btrfs balance commands caused the issue. But there is my script:

#!/bin/sh
fs="$1"
if [ -z "$fs" ]; then
echo usage: btrfs-balance / 0 1 5 10 20 50
exit 1
fi
fs="$1"
shift
for usage in d m; do for a in "$@"; do date; /bin/btrfs balance start "$fs" -v -${usage}usage=$a; done; done

And it was started at 07:30 with:

/usr/local/sbin/btrfs-balance / 0 1 2 5 10 20 30 50 70

I should add that the filesystem in question is backed by MD RAID10 and that is backed by four SSDs, so it's reasonably fast in IO, if that affects anything. There should have been no much competing IO at the time of the occurrence.

Before Duncan asks ;-), I only have a moderate number of subvolumes and snapshots, ie. one subvolume for each of /, /var/log/journal and /home, 24 snapshots of / and /home plus <10 snapshots of /.

Quoted 5 lines

Before that balance there was another balance on a another BTRFS RAID10, but given the time stamp I think I can easily say it wasn't the cause.

I don't really have other 'solutions' than disabling the rebalancing for the time being, and only use it as-needed as I had earlier done..

Try this (just sent a few minutes ago):
https://patchwork.kernel.org/patch/7463161/

Try this (just sent a few minutes ago):
https://patchwork.kernel.org/patch/7463161/