After getting a little annoyed with no space left errors when deleting files I started a btrfs balance process and 2-3 times the following appeared. Is this serious for my data or can I just ignore it because there is a security measure that handles even such errors ?
edit: Reported the bug at bugs.launchpad.net
[ 693.130413] ------------[ cut here ]------------
[ 693.130509] kernel BUG at /build/buildd/linux-3.5.0/fs/btrfs/relocation.c:2278!
[ 693.130645] invalid opcode: 0000 [#1] SMP
[ 693.130744] CPU 0
[ 693.130787] Modules linked in: sp5100_tco kvm_amd kvm psmouse k10temp serio_raw i2c_piix4 radeon ext2 ttm drm_kms_helper drm i2c_algo_bit mac_hid lp parport btrfs zlib_deflate libcrc32c hid_generic usbhid hid pata_atiixp r8169 microcode
[ 693.131415]
[ 693.131430] Pid: 2384, comm: btrfs Tainted: G W 3.5.0-23-generic #35-Ubuntu To Be Filled By O.E.M. To Be Filled By O.E.M./E350M1
[ 693.131678] RIP: 0010:[<ffffffffa00da3e2>] [<ffffffffa00da3e2>] merge_reloc_roots+0x142/0x150 [btrfs]
[ 693.131901] RSP: 0018:ffff88012315da58 EFLAGS: 00010286
[ 693.132004] RAX: 00000000ffffffe2 RBX: ffff88004ef5f000 RCX: 00000000ffffffe2
[ 693.132137] RDX: 0000000000000001 RSI: ffffffffa00ef050 RDI: ffff880138f04000
[ 693.132270] RBP: ffff88012315da88 R08: 0000000000000000 R09: ffff88013ec1b660
[ 693.132402] R10: ffffffffa006aaea R11: ffffffffa007e900 R12: ffff880134ce6000
[ 693.132535] R13: ffff88012315da58 R14: ffff880134ce6590 R15: ffff880134ce6000
[ 693.132669] FS: 00007f904729e740(0000) GS:ffff88013ec00000(0000) knlGS:0000000000000000
[ 693.132818] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 693.132927] CR2: 00007f3f2ce4c050 CR3: 00000001286a2000 CR4: 00000000000007f0
[ 693.133059] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 693.133193] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 693.133326] Process btrfs (pid: 2384, threadinfo ffff88012315c000, task ffff8801391ac500)
[ 693.133474] Stack:
[ 693.133519] ffff88012315da58 ffff88012315da58 00000000ffffffe2 ffff880134ce6020
[ 693.133689] ffff880134ce60e8 ffff88012e424510 ffff88012315db18 ffffffffa00da89d
[ 693.133859] ffff88012315db18 ffff88012315dae0 0000000000000001 00000000ffffffe4
[ 693.134029] Call Trace:
[ 693.134127] [<ffffffffa00da89d>] relocate_block_group+0x26d/0x690 [btrfs]
[ 693.134300] [<ffffffffa00dae6f>] btrfs_relocate_block_group+0x1af/0x2e0 [btrfs]
[ 693.134482] [<ffffffffa00b7165>] btrfs_relocate_chunk.isra.53+0x75/0x720 [btrfs]
[ 693.134663] [<ffffffffa00c60d8>] ? btrfs_set_lock_blocking_rw+0xa8/0xf0 [btrfs]
[ 693.134809] [<ffffffff81082203>] ? __wake_up+0x53/0x70
[ 693.134953] [<ffffffffa00aedc9>] ? release_extent_buffer.isra.38+0x79/0xe0 [btrfs]
[ 693.135138] [<ffffffffa00b3f07>] ? free_extent_buffer+0x37/0x90 [btrfs]
[ 693.135306] [<ffffffffa00bb397>] __btrfs_balance+0x427/0x7f0 [btrfs]
[ 693.135470] [<ffffffffa00bbad4>] btrfs_balance+0x374/0x550 [btrfs]
[ 693.135630] [<ffffffffa00c02d4>] btrfs_ioctl_balance+0x124/0x460 [btrfs]
[ 693.135765] [<ffffffff816838de>] ? _raw_spin_lock+0xe/0x20
[ 693.135913] [<ffffffffa00c55b9>] btrfs_ioctl+0x1049/0x12d0 [btrfs]
[ 693.136039] [<ffffffff8114b1d9>] ? handle_mm_fault+0x259/0x320
[ 693.136158] [<ffffffff8132f960>] ? rb_insert_color+0x110/0x150
[ 693.136276] [<ffffffff8168754c>] ? do_page_fault+0x1cc/0x4e0
[ 693.136392] [<ffffffff8114eb5f>] ? vma_link+0xcf/0xe0
[ 693.136497] [<ffffffff81193d19>] do_vfs_ioctl+0x99/0x590
[ 693.136607] [<ffffffff8116df80>] ? kmem_cache_free+0x20/0x100
[ 693.136723] [<ffffffff811942a9>] sys_ioctl+0x99/0xa0
[ 693.136828] [<ffffffff8168bb69>] system_call_fastpath+0x16/0x1b
[ 693.136941] Code: f9 ff ff 85 c0 74 97 0f 0b 85 d2 0f 85 08 ff ff ff 49 83 bc 24 80 05 00 00 00 75 15 48 83 c4 10 31 c0 5b 41 5c 41 5d 41 5e 5d c3 <0f> 0b 0f 0b 0f 0b 0f 0b 66 0f 1f 44 00 00 55 48 89 e5 41 57 41
[ 693.137853] RIP [<ffffffffa00da3e2>] merge_reloc_roots+0x142/0x150 [btrfs]
[ 693.138034] RSP <ffff88012315da58>
[ 693.138146] ---[ end trace 9311971051c0a78e ]---
