I'm going to pile on this thread because I have the same issue. I've seen this twice in just the past 2 days on a filesystem that was created a few weeks ago. Un-mounting and mounting again with no special options gets the filesystem back.
[Aug31 02:59] BTRFS: Transaction aborted (error -17) [ +0.000057] ------------[ cut here ]------------ [ +0.000021] WARNING: CPU: 4 PID: 21360 at fs/btrfs/extent-tree.c:2971 btrfs_run_delayed_refs+0x25c/0x260 [btrfs] [ +0.000001] Modules linked in: vmnet(OE) parport_pc vmw_vsock_vmci_transport vsock vmw_vmci vmmon(OE) cdc_acm rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache bnep cfg80211 nfnetlink_queue nfnetlink_log bluetooth ecdh_generic ipt_MASQUERADE nf_nat_masquerade_ipv4 nf_conntrack_netlink nfnetlink iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 xt_addrtype xt_conntrack nf_nat nf_conntrack libcrc32c br_netfilter bridge target_core_user uio target_core_pscsi target_core_file target_core_iblock iscsi_target_mod target_core_mod ppdev parport 8021q garp mrp stp llc fuse uinput nct6775 hwmon_vid bonding intel_rapl x86_pkg_temp_thermal intel_powerclamp ib_ipoib uvcvideo rdma_ucm videobuf2_vmalloc eeepc_wmi asus_wmi videobuf2_memops videobuf2_v4l2 sparse_keymap videobuf2_core snd_usb_audio coretemp ib_ucm [ +0.000023] iTCO_wdt rfkill crct10dif_pclmul crc32_pclmul video iTCO_vendor_support videodev mxm_wmi snd_usbmidi_lib ghash_clmulni_intel media snd_rawmidi ib_uverbs snd_hda_codec_realtek snd_hda_codec_generic ib_umad snd_hda_codec_hdmi joydev snd_hda_intel rdma_cm snd_hda_codec usblp intel_cstate snd_hda_core snd_hwdep ib_cm snd_seq snd_seq_device intel_uncore iw_cm snd_pcm snd_timer snd mei_me intel_rapl_perf i2c_i801 lpc_ich mei soundcore shpchp wmi mlx4_ib ib_core tpm_tis tpm_tis_core tpm nfsd auth_rpcgss binfmt_misc nfs_acl lockd grace sunrpc uas usb_storage mlx4_en btrfs xor amdkfd amd_iommu_v2 radeon mlx4_core i2c_algo_bit e1000e drm_kms_helper ttm r8169 ptp nvme raid6_pq drm crc32c_intel mii pps_core nvme_core devlink pcspkr i2c_dev [last unloaded: vboxdrv] [ +0.000027] CPU: 4 PID: 21360 Comm: btrfs-transacti Tainted: G W OE 4.12.8-200.fc25.x86_64 #1 [ +0.000001] Hardware name: ASUS All Series/SABERTOOTH X99, BIOS 3402 08/18/2016 [ +0.000001] task: ffff9ec6f11f0000 task.stack: ffffb0ab0de2c000 [ +0.000009] RIP: 0010:btrfs_run_delayed_refs+0x25c/0x260 [btrfs] [ +0.000001] RSP: 0018:ffffb0ab0de2fd28 EFLAGS: 00010282 [ +0.000001] RAX: 0000000000000026 RBX: ffff9ecb65040870 RCX: 0000000000000000 [ +0.000001] RDX: 0000000000000000 RSI: ffff9ecb6f10e128 RDI: ffff9ecb6f10e128 [ +0.000001] RBP: ffffb0ab0de2fd90 R08: 0000000000000001 R09: 0000000000000d20 [ +0.000001] R10: ffffb0ab0de2fc18 R11: 0000000000000d20 R12: ffff9ec493690000 [ +0.000001] R13: 00000000ffffffef R14: 00000000000000c8 R15: ffff9ecaa3a7af40 [ +0.000001] FS: 0000000000000000(0000) GS:ffff9ecb6f100000(0000) knlGS:0000000000000000 [ +0.000001] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000001] CR2: 00007f9512814002 CR3: 0000000336e09000 CR4: 00000000003406e0 [ +0.000001] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ +0.000001] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ +0.000000] Call Trace: [ +0.000013] ? free_extent_buffer+0x4b/0xa0 [btrfs] [ +0.000010] btrfs_start_dirty_block_groups+0x2f1/0x480 [btrfs] [ +0.000010] btrfs_commit_transaction+0x130/0x930 [btrfs] [ +0.000010] ? start_transaction+0x8d/0x410 [btrfs] [ +0.000009] transaction_kthread+0x18c/0x1b0 [btrfs] [ +0.000003] kthread+0x109/0x140 [ +0.000009] ? btrfs_cleanup_transaction+0x530/0x530 [btrfs] [ +0.000002] ? kthread_park+0x60/0x60 [ +0.000002] ret_from_fork+0x25/0x30 [ +0.000001] Code: 44 89 e9 ba 9b 0b 00 00 48 c7 c6 40 b8 72 c0 48 89 df e8 f8 b9 09 00 e9 ab fe ff ff 44 89 ee 48 c7 c7 58 18 73 c0 e8 db 88 b3 fd <0f> ff eb d1 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 53 48 8b 47 [ +0.000016] ---[ end trace 9a66996bbd24d74d ]--- [ +0.000002] BTRFS: error (device sdg1) in btrfs_run_delayed_refs:2971: errno=-17 Object already exists [ +0.000002] BTRFS info (device sdg1): forced readonly [ +0.001029] BTRFS error (device sdg1): pending csums is 3145728 Label: none uuid: d4fc5def-8b5c-4953-8d03-984a9d0dfcad Total devices 4 FS bytes used 543.25GiB devid 1 size 476.94GiB used 280.51GiB path /dev/sdd1 devid 2 size 476.94GiB used 280.51GiB path /dev/sde1 devid 3 size 476.94GiB used 280.51GiB path /dev/sdf1 devid 4 size 476.94GiB used 280.51GiB path /dev/sdg1 ---These are 4 SSDs on the motherboard's X99 SATA-III controller Data, RAID10: total=554.00GiB, used=538.33GiB System, RAID10: total=16.00MiB, used=80.00KiB Metadata, RAID10: total=7.00GiB, used=4.92GiB GlobalReserve, single: total=512.00MiB, used=0.00B Overall: Device size: 1.86TiB Device allocated: 1.10TiB Device unallocated: 785.72GiB Device missing: 0.00B Used: 1.06TiB Free (estimated): 408.53GiB (min: 408.53GiB) Data ratio: 2.00 Metadata ratio: 2.00 Global reserve: 512.00MiB (used: 0.00B) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html