Crashes in extent_io.c after "btrfs bad mapping eb" notice

[Franke <ttfranke@googlemail.com>]

Hello,

I have been having some crashes like this. Since I upgraded to 3.6.4 they have become common. The crashes happen pretty randomly during normal system usage. After the syslog messages the system stays semi usable for a minute, but when I run any new program it hangs. I had to downgrade to 3.6.2 to get my system usable again.

Is there any way I can help find the cause of those crashes? 

thanks,
Tobias Franke

logs here:
https://www.dropbox.com/s/1f6gh4k0zl2t5zq/btrfs_hangs_3-4-6.log

It starts like this:
Oct 30 22:42:36 localhost kernel: btrfs bad mapping eb start 982689189888 len 4096, wanted 4424 17
Oct 30 22:42:36 localhost kernel: ------------[ cut here ]------------
Oct 30 22:42:36 localhost kernel: WARNING: at fs/btrfs/extent_io.c:4661 map_private_extent_buffer+0x83/0xc9()
Oct 30 22:42:36 localhost kernel: Hardware name: A780L3L
Oct 30 22:42:36 localhost kernel: Modules linked in: hwmon_vid snd_hda_codec_hdmi nvidia(PO) snd_hda_codec_realtek snd_hda_intel snd_hda_codec i2c_piix4 k10temp
Oct 30 22:42:36 localhost kernel: Pid: 7143, comm: btrfs-endio-wri Tainted: P           O 3.6.4-gentoo #1
Oct 30 22:42:36 localhost kernel: Call Trace:
Oct 30 22:42:36 localhost kernel: [<ffffffff81030181>] ? warn_slowpath_common+0x78/0x8c
Oct 30 22:42:36 localhost kernel: [<ffffffff8127dc2e>] ? map_private_extent_buffer+0x83/0xc9
Oct 30 22:42:36 localhost kernel: [<ffffffff81249353>] ? generic_bin_search.clone.50+0xaa/0x130
Oct 30 22:42:36 localhost kernel: [<ffffffff8124c11a>] ? btrfs_search_old_slot+0x333/0x6ad
Oct 30 22:42:36 localhost kernel: [<ffffffff812a737d>] ? __resolve_indirect_refs+0x147/0x4b1
Oct 30 22:42:36 localhost kernel: [<ffffffff812a70bf>] ? __add_keyed_refs.clone.6+0x9e/0x215
Oct 30 22:42:36 localhost kernel: [<ffffffff812a6ba6>] ? __add_prelim_ref+0x3a/0xb9
Oct 30 22:42:36 localhost kernel: [<ffffffff812a7d54>] ? find_parent_nodes+0x553/0x7ca
Oct 30 22:42:36 localhost kernel: [<ffffffff812458b8>] ? leaf_space_used+0xaf/0xd7
Oct 30 22:42:36 localhost kernel: [<ffffffff812a8044>] ? btrfs_find_all_roots+0x79/0xd4
Oct 30 22:42:36 localhost kernel: [<ffffffff812aa1d0>] ? btrfs_qgroup_account_ref+0xd2/0x4a8
Oct 30 22:42:36 localhost kernel: [<ffffffff81278482>] ? alloc_extent_state+0x58/0x9d
Oct 30 22:42:36 localhost kernel: [<ffffffff810e8245>] ? kmem_cache_free+0x12/0xbd
Oct 30 22:42:36 localhost kernel: [<ffffffff81253c93>] ? btrfs_delayed_refs_qgroup_accounting+0x9e/0xca
Oct 30 22:42:36 localhost kernel: [<ffffffff81266723>] ? __btrfs_end_transaction+0x4e/0x293
Oct 30 22:42:36 localhost kernel: [<ffffffff8126bb26>] ? btrfs_finish_ordered_io+0x2e1/0x332
Oct 30 22:42:36 localhost kernel: [<ffffffff8103cfae>] ? run_timer_softirq+0x2c2/0x2c2
Oct 30 22:42:36 localhost kernel: [<ffffffff81286398>] ? worker_loop+0x174/0x4c0
Oct 30 22:42:36 localhost kernel: [<ffffffff81286224>] ? btrfs_queue_worker+0x261/0x261
Oct 30 22:42:36 localhost kernel: [<ffffffff81286224>] ? btrfs_queue_worker+0x261/0x261
Oct 30 22:42:36 localhost kernel: [<ffffffff8104b293>] ? kthread+0x81/0x89
Oct 30 22:42:36 localhost kernel: [<ffffffff815de774>] ? kernel_thread_helper+0x4/0x10
Oct 30 22:42:36 localhost kernel: [<ffffffff8104b212>] ? kthread_freezable_should_stop+0x52/0x52
Oct 30 22:42:36 localhost kernel: [<ffffffff815de770>] ? gs_change+0xb/0xb
Oct 30 22:42:36 localhost kernel: ---[ end trace cb2d15ce8c2d83ec ]---
Oct 30 22:42:36 localhost kernel: ------------[ cut here ]------------