Just hit this while running trinity. WARNING: CPU: 3 PID: 9612 at fs/btrfs/extent-tree.c:3799 btrfs_free_reserved_data_space+0x1d1/0x280 [btrfs]() Modules linked in: rfcomm hidp bnep af_key llc2 scsi_transport_iscsi nfnetlink sctp libcrc32c can_raw can_bcm nfc caif_socket caif af_802154 ieee802154 phonet af_rxrpc bluetooth can pppoe pppox ppp_generic slhc irda crc_ccitt rds rose x25 atm netrom appletalk ipx p8023 psnap p8022 llc ax25 cfg80211 rfkill btrfs xor coretemp hwmon x86_pkg_temp_thermal kvm_intel snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic kvm crct10dif_pclmul crc32c_intel ghash_clmulni_intel raid6_pq snd_hda_intel microcode snd_hda_controller pcspkr snd_hda_codec serio_raw snd_hwdep snd_seq snd_seq_device usb_debug snd_pcm e1000e ptp shpchp pps_core snd_timer snd soundcore CPU: 3 PID: 9612 Comm: trinity-c85 Not tainted 3.18.0-rc1+ #74 0000000000000009 000000009989d5b8 ffff88018a337ba8 ffffffffaf86cc97 0000000000000000 0000000000000000 ffff88018a337be8 ffffffffaf07f301 ffff88022ddf8d40 ffff88023f799148 000000007fbbf000 ffff88009c2b59c8 Call Trace: [<ffffffffaf86cc97>] dump_stack+0x4f/0x7c [<ffffffffaf07f301>] warn_slowpath_common+0x81/0xa0 [<ffffffffaf07f41a>] warn_slowpath_null+0x1a/0x20 [<ffffffffc045b831>] btrfs_free_reserved_data_space+0x1d1/0x280 [btrfs] [<ffffffffc045d0b2>] btrfs_delalloc_release_space+0x22/0x30 [btrfs] [<ffffffffc047994b>] btrfs_direct_IO+0x33b/0x350 [btrfs] [<ffffffffc0487400>] ? btrfs_page_exists_in_range+0x2c0/0x2c0 [btrfs] [<ffffffffc047b2b0>] ? btrfs_real_readdir+0x5e0/0x5e0 [btrfs] [<ffffffffaf1adbb4>] generic_file_direct_write+0xc4/0x1a0 [<ffffffffc048b246>] btrfs_file_write_iter+0x186/0x560 [btrfs] [<ffffffffaf22abde>] new_sync_write+0x8e/0xd0 [<ffffffffaf22b5ca>] vfs_write+0xba/0x1f0 [<ffffffffaf24fbce>] ? __fget_light+0xbe/0xe0 [<ffffffffaf22c2d2>] SyS_pwrite64+0x92/0xc0 [<ffffffffaf877d49>] tracesys_phase2+0xd4/0xd9