When booting on an Ubuntu kernel I am hitting this in my dmesg with an external drive I have. I am wondering if this is a bug or just a common issue. 8518.918519] ------------[ cut here ]------------ [ 8518.918528] WARNING: CPU: 1 PID: 13778 at /build/buildd/linux-3.13.0/fs/btrfs/super.c:254 __btrfs_abort_transaction+0x50/0x110 [btrfs]() [ 8518.918529] btrfs: Transaction aborted (error -5) [ 8518.918530] Modules linked in: btrfs raid6_pq libcrc32c xor ses enclosure usb_storage bnep rfcomm bluetooth hid_generic usbhid hid eeepc_wmi asus_wmi sparse_keymap intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_hdmi aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd serio_raw snd_hda_codec_realtek lpc_ich snd_hda_intel snd_hda_codec snd_hwdep snd_seq_midi snd_seq_midi_event snd_pcm snd_rawmidi snd_page_alloc fglrx(POF) snd_seq parport_pc snd_seq_device snd_timer ppdev wmi mei_me snd mei mac_hid lp parport soundcore amd_iommu_v2 video ahci libahci r8169 mii [ 8518.918560] CPU: 1 PID: 13778 Comm: umount Tainted: PF W O 3.13.0-34-generic #60-Ubuntu [ 8518.918561] Hardware name: System manufacturer System Product Name/P8Z68-V LE, BIOS 3506 01/17/2012 [ 8518.918562] 0000000000000009 ffff8801c9ad5c50 ffffffff8171bd94 ffff8801c9ad5c98 [ 8518.918564] ffff8801c9ad5c88 ffffffff810676cd 00000000fffffffb ffff880211d72800 [ 8518.918566] ffff8801c49d8000 ffffffffa0bb2e90 000000000000060b ffff8801c9ad5ce8 [ 8518.918568] Call Trace: [ 8518.918573] [<ffffffff8171bd94>] dump_stack+0x45/0x56 [ 8518.918576] [<ffffffff810676cd>] warn_slowpath_common+0x7d/0xa0 [ 8518.918578] [<ffffffff8106773c>] warn_slowpath_fmt+0x4c/0x50 [ 8518.918583] [<ffffffffa0b16f00>] __btrfs_abort_transaction+0x50/0x110 [btrfs] [ 8518.918591] [<ffffffffa0b40ebe>] cleanup_transaction+0x6e/0x290 [btrfs] [ 8518.918594] [<ffffffff810aaf00>] ? prepare_to_wait_event+0x100/0x100 [ 8518.918601] [<ffffffffa0b41e3a>] btrfs_commit_transaction+0x6ea/0x970 [btrfs] [ 8518.918608] [<ffffffffa0b3c00f>] btrfs_commit_super+0x8f/0xa0 [btrfs] [ 8518.918614] [<ffffffffa0b3dac0>] close_ctree+0x1e0/0x290 [btrfs] [ 8518.918617] [<ffffffff811d8c2c>] ? evict_inodes+0x11c/0x130 [ 8518.918622] [<ffffffffa0b139b9>] btrfs_put_super+0x19/0x20 [btrfs] [ 8518.918625] [<ffffffff811beda2>] generic_shutdown_super+0x72/0xf0 [ 8518.918627] [<ffffffff811befe2>] kill_anon_super+0x12/0x20 [ 8518.918631] [<ffffffffa0b15eb6>] btrfs_kill_super+0x16/0x90 [btrfs] [ 8518.918634] [<ffffffff811bf33d>] deactivate_locked_super+0x3d/0x60 [ 8518.918636] [<ffffffff811bf8f6>] deactivate_super+0x46/0x60 [ 8518.918638] [<ffffffff811dc5f6>] mntput_no_expire+0xd6/0x170 [ 8518.918640] [<ffffffff811ddb6e>] SyS_umount+0x8e/0x100 [ 8518.918642] [<ffffffff8172c97f>] tracesys+0xe1/0xe6 [ 8518.918644] ---[ end trace 1a6b295c1d8ad4c3 ]--- Nick