I had an 8TB btrfs filesystem setup with my data, and added a 4TB and 3TB drive to it and then ran a raid1 conversion using the command btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt/btrfs It was running OK, but then I restarted the computer without pausing the rebalance (I wasn't aware that would be necessary). Upon reboot, the system got stuck on the mounting operation (as well as decryption of two of the drives - all drives are setup with encryption and automatically get unlocked via keyfiles at boot) and dropped me to a root shell. I removed the line which was mounting the btrfs volume in fstab, and rebooted successfully, however now when I attempt to mount the btrfs volume normally it just hangs with no response, and the command never terminates and cannot be killed. I am able to mount the drive read-only, but am unable to mount it as read-write even when using the mount option "skip_balance". Relevant debug info: uname -a Linux gaussBonnetXeon 4.8.0-0.bpo.2-amd64 #1 SMP Debian 4.8.11-1~bpo8+1 (2016-12-14) x86_64 GNU/Linux btrfs --version btrfs-progs v4.7.3 btrfs fi show Label: none uuid: d5c3f49c-3c69-4fd8-b9ab-272c0dbc1eab Total devices 3 FS bytes used 2.61TiB devid 1 size 7.00TiB used 2.64TiB path /dev/mapper/Seagate_Archive_8TB-btrfs devid 2 size 3.64TiB used 930.00GiB path /dev/mapper/4TB devid 3 size 2.73TiB used 0.00B path /dev/mapper/3TB btrfs fi df /mnt/btrfs Data, RAID1: total=925.00GiB, used=912.85GiB Data, single: total=1.71TiB, used=1.71TiB System, DUP: total=8.00MiB, used=352.00KiB Metadata, RAID1: total=5.00GiB, used=2.12GiB Metadata, DUP: total=8.50GiB, used=7.61GiB GlobalReserve, single: total=512.00MiB, used=1.05MiB dmesg (from when I try to mount as rw): [ 3202.640391] BTRFS info (device dm-10): disk space caching is enabled [ 3377.624283] BUG: unable to handle kernel paging request at fffffffffffffe10 [ 3377.624293] IP: [<ffffffffc0618c9b>] qgroup_fix_relocated_data_extents+0x2b/0x2c0 [btrfs] [ 3377.624341] PGD 111e09067 PUD 111e0b067 PMD 0 [ 3377.624348] Oops: 0000 [#1] SMP [ 3377.624352] Modules linked in: ipt_REJECT(E) nf_reject_ipv4(E) rfcomm(E) xt_multiport(E) iptable_filter(E) ip_tables(E) x_tables(E) binfmt_misc(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) bnep(E) cfg80211(E) snd_hda_codec_hdmi(E) nvidia_drm(POE) btusb(E) btrtl(E) drm_kms_helper(E) btbcm(E) btintel(E) drm(E) bluetooth(E) iTCO_wdt(E) iTCO_vendor_support(E) coretemp(E) joydev(E) kvm_intel(E) snd_hda_intel(E) snd_ca0106(E) rfkill(E) evdev(E) snd_hda_codec(E) nvidia_modeset(POE) snd_rawmidi(E) kvm(E) snd_seq_device(E) snd_hda_core(E) snd_ac97_codec(E) snd_hwdep(E) i7core_edac(E) i2c_i801(E) snd_pcm(E) nvidia(POE) irqbypass(E) pcspkr(E) edac_core(E) i2c_smbus(E) snd_timer(E) snd(E) soundcore(E) ac97_bus(E) ipmi_si(E) ipmi_msghandler(E) shpchp(E) lpc_ich(E) mfd_core(E) acpi_cpufreq(E) [ 3377.624400] button(E) tpm_tis(E) tpm_tis_core(E) tpm(E) fuse(E) parport_pc(E) ppdev(E) lp(E) parport(E) autofs4(E) ext4(E) crc16(E) jbd2(E) fscrypto(E) mbcache(E) btrfs(E) xor(E) raid6_pq(E) xts(E) gf128mul(E) algif_skcipher(E) af_alg(E) dm_crypt(E) dm_mod(E) sr_mod(E) cdrom(E) hid_generic(E) usbhid(E) hid(E) sg(E) sd_mod(E) ahci(E) libahci(E) xhci_pci(E) crc32c_intel(E) ehci_pci(E) xhci_hcd(E) libata(E) ehci_hcd(E) e1000e(E) scsi_mod(E) usbcore(E) ptp(E) usb_common(E) pps_core(E) fjes(E) [ 3377.624426] CPU: 0 PID: 1909 Comm: mount Tainted: P OE 4.8.0-0.bpo.2-amd64 #1 Debian 4.8.11-1~bpo8+1 [ 3377.624428] Hardware name: Intel Corporation S3420GP/S3420GP, BIOS S3420GP.86B.01.00.0040.021120101620 02/11/2010 [ 3377.624430] task: ffff9277e47f7100 task.stack: ffff92770a060000 [ 3377.624431] RIP: 0010:[<ffffffffc0618c9b>] [<ffffffffc0618c9b>] qgroup_fix_relocated_data_extents+0x2b/0x2c0 [btrfs] [ 3377.624454] RSP: 0018:ffff92770a063cb8 EFLAGS: 00210246 [ 3377.624455] RAX: ffff927805ee3000 RBX: ffff92772a31de00 RCX: 0000000000000000 [ 3377.624457] RDX: ffff9277edf22090 RSI: ffff9274d3f5b800 RDI: ffff9277edf22000 [ 3377.624458] RBP: ffff927805e5d800 R08: 0000000000000000 R09: ffff9277edf22000 [ 3377.624460] R10: 0000000000000000 R11: 0000000000000000 R12: ffff92770a063d50 [ 3377.624461] R13: ffff9274d3f5b800 R14: 0000000000000000 R15: ffff9277edf22000 [ 3377.624463] FS: 00007f0f98765840(0000) GS:ffff92781fc00000(0000) knlGS:0000000000000000 [ 3377.624465] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3377.624467] CR2: fffffffffffffe10 CR3: 000000034b952000 CR4: 00000000000006f0 [ 3377.624468] Stack: [ 3377.624470] ffffffffc05c14a2 0000000000000801 ffff9277edf22000 ffff927805ee3000 [ 3377.624473] 0000000000000801 ffff9277edf22000 ffffffffc05c3ed6 0000000000000000 [ 3377.624476] 0000000000000000 00000000dc2f7325 ffff92772a31de00 ffff927805e5d800 [ 3377.624478] Call Trace: [ 3377.624497] [<ffffffffc05c14a2>] ? join_transaction.isra.15+0x22/0x3f0 [btrfs] [ 3377.624516] [<ffffffffc05c3ed6>] ? start_transaction+0x96/0x4d0 [btrfs] [ 3377.624537] [<ffffffffc061d288>] ? btrfs_recover_relocation+0x2e8/0x420 [btrfs] [ 3377.624551] [<ffffffffc0592fff>] ? btrfs_remount+0x40f/0x570 [btrfs] [ 3377.624555] [<ffffffff8941d852>] ? shrink_dcache_sb+0xd2/0x120 [ 3377.624558] [<ffffffff894087c8>] ? do_remount_sb+0x68/0x1d0 [ 3377.624561] [<ffffffff89428249>] ? do_mount+0x709/0xc70 [ 3377.624564] [<ffffffff893a256a>] ? memdup_user+0x4a/0x70 [ 3377.624566] [<ffffffff89428a94>] ? SyS_mount+0x84/0xc0 [ 3377.624570] [<ffffffff897f3b76>] ? system_call_fast_compare_end+0xc/0x96 [ 3377.624571] Code: 66 66 66 66 90 41 57 41 56 41 55 41 54 55 53 48 83 ec 50 4c 8b 76 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 48 31 c0 48 8b 46 08 <49> 8b ae 10 fe ff ff 48 8b 98 f0 01 00 00 31 c0 f6 83 50 0d 00 [ 3377.624600] RIP [<ffffffffc0618c9b>] qgroup_fix_relocated_data_extents+0x2b/0x2c0 [btrfs] [ 3377.624621] RSP <ffff92770a063cb8> [ 3377.624622] CR2: fffffffffffffe10 [ 3377.624624] ---[ end trace 547a7c76f9cea091 ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html