Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Nicholas Lee]

Hi list! I recently butchered my filesystem, and I was wondering if anyone knows how to help.

Problem: My filesystem is screwed up, and I can't mount it at all right now. In the logs, the problem begins around 45s. 

Background: I'm running a 6x4TB RAID5 array using md. I have a few virtual machines using said array, and one of them is a btrfs storage server. I ran into some issues where FS errors would cause the host system to enter a read-only state, which led to the corruption of the guest's file system. Adding insult to injury, this occurred right as I began the initial backup to another system with rsync. :(

What I've done so far: I've made a few attempts to mount the partition in read-only recovery mode to no avail. I created another virtual disk and installed ArchBang to use as a recovery environment. I also tried running find-root, but I got no console output after two days of it running, and it just sat there burning CPU time. 

I would be seriously grateful to anyone that can figure out a way to mount/fix this partition, and I'd be willing to send some bitcoin over to anyone that can help me get partition mounted and/or repaired!


dmesg's output:

[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Linux version 3.9.8-1-ARCH (tobias@testing-i686) (gcc version 4.8.1 (GCC) ) #1 SMP PREEMPT Fri Jun 28 07:43:59 CEST 2013
[    0.000000] e820: BIOS-provided physical RAM map:
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[    0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000007fffdfff] usable
[    0.000000] BIOS-e820: [mem 0x000000007fffe000-0x000000007fffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
[    0.000000] Notice: NX (Execute Disable) protection cannot be enabled: non-PAE kernel!
[    0.000000] SMBIOS 2.4 present.
[    0.000000] DMI: Bochs Bochs, BIOS Bochs 01/01/2011
[    0.000000] Hypervisor detected: KVM
[    0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[    0.000000] e820: remove [mem 0x000a0000-0x000fffff] usable
[    0.000000] e820: last_pfn = 0x7fffe max_arch_pfn = 0x100000
[    0.000000] MTRR default type: write-back
[    0.000000] MTRR fixed ranges enabled:
[    0.000000]   00000-9FFFF write-back
[    0.000000]   A0000-BFFFF uncachable
[    0.000000]   C0000-FFFFF write-protect
[    0.000000] MTRR variable ranges enabled:
[    0.000000]   0 base 0080000000 mask FF80000000 uncachable
[    0.000000]   1 disabled
[    0.000000]   2 disabled
[    0.000000]   3 disabled
[    0.000000]   4 disabled
[    0.000000]   5 disabled
[    0.000000]   6 disabled
[    0.000000]   7 disabled
[    0.000000] PAT not supported by CPU.
[    0.000000] found SMP MP-table at [mem 0x000fdaa0-0x000fdaaf] mapped at [c00fdaa0]
[    0.000000] Scanning 1 areas for low memory corruption
[    0.000000] initial memory mapped: [mem 0x00000000-0x00bfffff]
[    0.000000] Base memory trampoline at [c009b000] 9b000 size 16384
[    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
[    0.000000]  [mem 0x00000000-0x000fffff] page 4k
[    0.000000] init_memory_mapping: [mem 0x37000000-0x373fffff]
[    0.000000]  [mem 0x37000000-0x373fffff] page 2M
[    0.000000] init_memory_mapping: [mem 0x30000000-0x36ffffff]
[    0.000000]  [mem 0x30000000-0x36ffffff] page 2M
[    0.000000] init_memory_mapping: [mem 0x00100000-0x2fffffff]
[    0.000000]  [mem 0x00100000-0x003fffff] page 4k
[    0.000000]  [mem 0x00400000-0x2fffffff] page 2M
[    0.000000] init_memory_mapping: [mem 0x37400000-0x377fdfff]
[    0.000000]  [mem 0x37400000-0x377fdfff] page 4k
[    0.000000] BRK [0x0083e000, 0x0083efff] PGTABLE
[    0.000000] RAMDISK: [mem 0x7eff7000-0x7ffdcfff]
[    0.000000] Allocated new RAMDISK: [mem 0x36818000-0x377fdb2f]
[    0.000000] Move RAMDISK from [mem 0x7eff7000-0x7ffdcb2f] to [mem 0x36818000-0x377fdb2f]
[    0.000000] ACPI: RSDP 000fd8c0 00014 (v00 BOCHS )
[    0.000000] ACPI: RSDT 7fffe380 00034 (v01 BOCHS  BXPCRSDT 00000001 BXPC 00000001)
[    0.000000] ACPI: FACP 7fffff80 00074 (v01 BOCHS  BXPCFACP 00000001 BXPC 00000001)
[    0.000000] ACPI: DSDT 7fffe3c0 011A9 (v01   BXPC   BXDSDT 00000001 INTL 20100528)
[    0.000000] ACPI: FACS 7fffff40 00040
[    0.000000] ACPI: SSDT 7ffff6e0 00858 (v01 BOCHS  BXPCSSDT 00000001 BXPC 00000001)
[    0.000000] ACPI: APIC 7ffff5b0 00090 (v01 BOCHS  BXPCAPIC 00000001 BXPC 00000001)
[    0.000000] ACPI: HPET 7ffff570 00038 (v01 BOCHS  BXPCHPET 00000001 BXPC 00000001)
[    0.000000] ACPI: Local APIC address 0xfee00000
[    0.000000] 1160MB HIGHMEM available.
[    0.000000] 887MB LOWMEM available.
[    0.000000]   mapped low ram: 0 - 377fe000
[    0.000000]   low ram: 0 - 377fe000
[    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00
[    0.000000] kvm-clock: cpu 0, msr 0:36817001, boot clock
[    0.000000] BRK [0x0083f000, 0x0083ffff] PGTABLE
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00001000-0x00ffffff]
[    0.000000]   Normal   [mem 0x01000000-0x377fdfff]
[    0.000000]   HighMem  [mem 0x377fe000-0x7fffdfff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x00001000-0x0009efff]
[    0.000000]   node   0: [mem 0x00100000-0x7fffdfff]
[    0.000000] On node 0 totalpages: 524188
[    0.000000] free_area_init_node: node 0, pgdat c06aeb00, node_mem_map f5817020
[    0.000000]   DMA zone: 32 pages used for memmap
[    0.000000]   DMA zone: 0 pages reserved
[    0.000000]   DMA zone: 3998 pages, LIFO batch:0
[    0.000000]   Normal zone: 1744 pages used for memmap
[    0.000000]   Normal zone: 223230 pages, LIFO batch:31
[    0.000000]   HighMem zone: 2320 pages used for memmap
[    0.000000]   HighMem zone: 296960 pages, LIFO batch:31
[    0.000000] Using APIC driver default
[    0.000000] ACPI: PM-Timer IO Port: 0xb008
[    0.000000] ACPI: Local APIC address 0xfee00000
[    0.000000] ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)
[    0.000000] ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled)
[    0.000000] ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] enabled)
[    0.000000] ACPI: LAPIC (acpi_id[0x03] lapic_id[0x03] enabled)
[    0.000000] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1])
[    0.000000] ACPI: IOAPIC (id[0x00] address[0xfec00000] gsi_base[0])
[    0.000000] IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level)
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level)
[    0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level)
[    0.000000] ACPI: IRQ0 used by override.
[    0.000000] ACPI: IRQ2 used by override.
[    0.000000] ACPI: IRQ5 used by override.
[    0.000000] ACPI: IRQ9 used by override.
[    0.000000] ACPI: IRQ10 used by override.
[    0.000000] ACPI: IRQ11 used by override.
[    0.000000] Using ACPI (MADT) for SMP configuration information
[    0.000000] ACPI: HPET id: 0x8086a201 base: 0xfed00000
[    0.000000] smpboot: Allowing 4 CPUs, 0 hotplug CPUs
[    0.000000] nr_irqs_gsi: 40
[    0.000000] PM: Registered nosave memory: 000000000009f000 - 00000000000a0000
[    0.000000] PM: Registered nosave memory: 00000000000a0000 - 00000000000f0000
[    0.000000] PM: Registered nosave memory: 00000000000f0000 - 0000000000100000
[    0.000000] e820: [mem 0x80000000-0xfeffbfff] available for PCI devices
[    0.000000] Booting paravirtualized kernel on KVM
[    0.000000] setup_percpu: NR_CPUS:8 nr_cpumask_bits:8 nr_cpu_ids:4 nr_node_ids:1
[    0.000000] PERCPU: Embedded 14 pages/cpu @f57d3000 s33280 r0 d24064 u57344
[    0.000000] pcpu-alloc: s33280 r0 d24064 u57344 alloc=14*4096
[    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3 
[    0.000000] kvm-clock: cpu 0, msr 0:36817001, primary cpu clock
[    0.000000] KVM setup async PF for cpu 0
[    0.000000] kvm-stealtime: cpu 0, msr 357d58c0
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 522412
[    0.000000] Kernel command line: archisobasedir=arch archisolabel=ARCH_201307 initrd=boot/i686/archiso.img BOOT_IMAGE=boot/i686/vmlinuz 
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] __ex_table already sorted, skipping sort
[    0.000000] Initializing CPU#0
[    0.000000] allocated 4194280 bytes of page_cgroup
[    0.000000] please try 'cgroup_disable=memory' option if you don't want memory cgroups
[    0.000000] Initializing HighMem for node 0 (000377fe:0007fffe)
[    0.000000] Memory: 2051424k/2097144k available (4178k kernel code, 45328k reserved, 1705k data, 572k init, 1187840k highmem)
[    0.000000] virtual kernel memory layout:
    fixmap  : 0xfff15000 - 0xfffff000   ( 936 kB)
    pkmap   : 0xff800000 - 0xffc00000   (4096 kB)
    vmalloc : 0xf7ffe000 - 0xff7fe000   ( 120 MB)
    lowmem  : 0xc0000000 - 0xf77fe000   ( 887 MB)
      .init : 0xc06bf000 - 0xc074e000   ( 572 kB)
      .data : 0xc0514854 - 0xc06bee00   (1705 kB)
      .text : 0xc0100000 - 0xc0514854   (4178 kB)
[    0.000000] Checking if this processor honours the WP bit even in supervisor mode...Ok.
[    0.000000] SLUB: Genslabs=15, HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] Preemptible hierarchical RCU implementation.
[    0.000000] 	RCU dyntick-idle grace-period acceleration is enabled.
[    0.000000] 	Dump stacks of tasks blocking RCU-preempt GP.
[    0.000000] 	RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
[    0.000000] NR_IRQS:2304 nr_irqs:712 16
[    0.000000] CPU 0 irqstacks, hard=f4c08000 soft=f4c0a000
[    0.000000] Console: colour VGA+ 80x25
[    0.000000] console [tty0] enabled
[    0.000000] hpet clockevent registered
[    0.000000] tsc: Detected 3292.518 MHz processor
[    0.006666] Calibrating delay loop (skipped) preset value.. 6587.41 BogoMIPS (lpj=10975060)
[    0.006666] pid_max: default: 32768 minimum: 301
[    0.006666] Security Framework initialized
[    0.006666] AppArmor: AppArmor disabled by boot time parameter
[    0.006666] Mount-cache hash table entries: 512
[    0.006666] Initializing cgroup subsys cpuacct
[    0.006666] Initializing cgroup subsys memory
[    0.006666] Initializing cgroup subsys devices
[    0.006666] Initializing cgroup subsys freezer
[    0.006666] Initializing cgroup subsys net_cls
[    0.006666] Initializing cgroup subsys blkio
[    0.006666] mce: CPU supports 10 MCE banks
[    0.006666] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0
tlb_flushall_shift: 6
[    0.006666] Freeing SMP alternatives: 16k freed
[    0.006666] ACPI: Core revision 20130117
[    0.006666] ACPI: All ACPI Tables successfully acquired
[    0.006666] ftrace: allocating 18432 entries in 37 pages
[    0.010116] Enabling APIC mode:  Flat.  Using 1 I/O APICs
[    0.010906] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[    0.010908] smpboot: CPU0: Intel QEMU Virtual CPU version 1.4.0 (fam: 06, model: 02, stepping: 03)
[    0.013333] Performance Events: unsupported p6 CPU model 2 no PMU driver, software events only.
[    0.040094] NMI watchdog: disabled (cpu0): hardware events not enabled
[    0.046786] CPU 1 irqstacks, hard=f4cde000 soft=f4ce0000
[    0.003333] Initializing CPU#1
[    0.006666] kvm-clock: cpu 1, msr 0:36817041, secondary cpu clock
[    0.063354] KVM setup async PF for cpu 1
[    0.063362] kvm-stealtime: cpu 1, msr 357e38c0
[    0.046788] smpboot: Booting Node   0, Processors  #1
[    0.070133] CPU 2 irqstacks, hard=f4d00000 soft=f4d02000
[    0.003333] Initializing CPU#2
[    0.006666] kvm-clock: cpu 2, msr 0:36817081, secondary cpu clock
[    0.086699] KVM setup async PF for cpu 2
[    0.086707] kvm-stealtime: cpu 2, msr 357f18c0
[    0.070136]  #2
[    0.093456] CPU 3 irqstacks, hard=f4d1e000 soft=f4d20000
[    0.093458]  #3 OK
[    0.003333] Initializing CPU#3
[    0.006666] kvm-clock: cpu 3, msr 0:368170c1, secondary cpu clock
[    0.110048] Brought up 4 CPUs
[    0.110040] KVM setup async PF for cpu 3
[    0.110053] smpboot: Total of 4 processors activated (26350.65 BogoMIPS)
[    0.110046] kvm-stealtime: cpu 3, msr 357ff8c0
[    0.110459] devtmpfs: initialized
[    0.111181] RTC time: 16:07:43, date: 08/19/13
[    0.111287] NET: Registered protocol family 16
[    0.113779] ACPI: bus type PCI registered
[    0.113779] PCI: PCI BIOS revision 2.10 entry at 0xfc6d2, last bus=0
[    0.113779] PCI: Using configuration type 1 for base access
[    0.114146] bio: create slab <bio-0> at 0
[    0.114146] ACPI: Added _OSI(Module Device)
[    0.114146] ACPI: Added _OSI(Processor Device)
[    0.114146] ACPI: Added _OSI(3.0 _SCP Extensions)
[    0.114146] ACPI: Added _OSI(Processor Aggregator Device)
[    0.114146] ACPI: EC: Look up EC in DSDT
[    0.115243] ACPI: Interpreter enabled
[    0.115253] ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [\_S1_] (20130117/hwxface-568)
[    0.115259] ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [\_S2_] (20130117/hwxface-568)
[    0.115272] ACPI: (supports S0 S3 S4 S5)
[    0.115274] ACPI: Using IOAPIC for interrupt routing
[    0.115292] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
[    0.119342] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
[    0.119405] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended PCI configuration space under this bridge.
[    0.119423] PCI host bridge to bus 0000:00
[    0.119426] pci_bus 0000:00: root bus resource [bus 00-ff]
[    0.119427] pci_bus 0000:00: root bus resource [io  0x0000-0x0cf7]
[    0.119429] pci_bus 0000:00: root bus resource [io  0x0d00-0xffff]
[    0.119430] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff]
[    0.119431] pci_bus 0000:00: root bus resource [mem 0x80000000-0xfebfffff]
[    0.119461] pci 0000:00:00.0: [8086:1237] type 00 class 0x060000
[    0.119803] pci 0000:00:01.0: [8086:7000] type 00 class 0x060100
[    0.120406] pci 0000:00:01.1: [8086:7010] type 00 class 0x010180
[    0.126673] pci 0000:00:01.1: reg 20: [io  0xc1c0-0xc1cf]
[    0.129217] pci 0000:00:01.2: [8086:7020] type 00 class 0x0c0300
[    0.135153] pci 0000:00:01.2: reg 20: [io  0xc140-0xc15f]
[    0.137387] pci 0000:00:01.3: [8086:7113] type 00 class 0x068000
[    0.137613] pci 0000:00:01.3: quirk: [io  0xb000-0xb03f] claimed by PIIX4 ACPI
[    0.137620] pci 0000:00:01.3: quirk: [io  0xb100-0xb10f] claimed by PIIX4 SMB
[    0.137743] pci 0000:00:02.0: [1013:00b8] type 00 class 0x030000
[    0.141248] pci 0000:00:02.0: reg 10: [mem 0xfc000000-0xfdffffff pref]
[    0.143352] pci 0000:00:02.0: reg 14: [mem 0xfebf2000-0xfebf2fff]
[    0.155789] pci 0000:00:02.0: reg 30: [mem 0xfebe0000-0xfebeffff pref]
[    0.155975] pci 0000:00:03.0: [1af4:1000] type 00 class 0x020000
[    0.157849] pci 0000:00:03.0: reg 10: [io  0xc160-0xc17f]
[    0.160004] pci 0000:00:03.0: reg 14: [mem 0xfebf3000-0xfebf3fff]
[    0.172317] pci 0000:00:03.0: reg 30: [mem 0xfebc0000-0xfebdffff pref]
[    0.172570] pci 0000:00:04.0: [8086:2922] type 00 class 0x010601
[    0.183339] pci 0000:00:04.0: reg 20: [io  0xc180-0xc19f]
[    0.186672] pci 0000:00:04.0: reg 24: [mem 0xfebf4000-0xfebf4fff]
[    0.189288] pci 0000:00:05.0: [1000:0012] type 00 class 0x010000
[    0.191743] pci 0000:00:05.0: reg 10: [io  0xc000-0xc0ff]
[    0.195064] pci 0000:00:05.0: reg 14: [mem 0xfebf5000-0xfebf53ff]
[    0.198385] pci 0000:00:05.0: reg 18: [mem 0xfebf0000-0xfebf1fff]
[    0.216805] pci 0000:00:06.0: [1af4:1002] type 00 class 0x00ff00
[    0.218000] pci 0000:00:06.0: reg 10: [io  0xc1a0-0xc1bf]
[    0.226885] pci 0000:00:07.0: [1af4:1001] type 00 class 0x010000
[    0.229230] pci 0000:00:07.0: reg 10: [io  0xc100-0xc13f]
[    0.231224] pci 0000:00:07.0: reg 14: [mem 0xfebf6000-0xfebf6fff]
[    0.243591] pci_bus 0000:00: on NUMA node 0
[    0.243599] acpi PNP0A03:00: ACPI _OSC support notification failed, disabling PCIe ASPM
[    0.243601] acpi PNP0A03:00: Unable to request _OSC control (_OSC support mask: 0x08)
[    0.244007] ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11)
[    0.244075] ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11)
[    0.244131] ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11)
[    0.244186] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11)
[    0.244218] ACPI: PCI Interrupt Link [LNKS] (IRQs *9)
[    0.244435] ACPI: Enabled 16 GPEs in block 00 to 0F
[    0.244439] acpi root: \_SB_.PCI0 notify handler is installed
[    0.244453] Found 1 acpi root devices
[    0.244662] ACPI: No dock devices found.
[    0.244746] vgaarb: device added: PCI:0000:00:02.0,decodes=io+mem,owns=io+mem,locks=none
[    0.244747] vgaarb: loaded
[    0.244748] vgaarb: bridge control possible 0000:00:02.0
[    0.244785] PCI: Using ACPI for IRQ routing
[    0.244788] PCI: pci_cache_line_size set to 64 bytes
[    0.244902] e820: reserve RAM buffer [mem 0x0009fc00-0x0009ffff]
[    0.244904] e820: reserve RAM buffer [mem 0x7fffe000-0x7fffffff]
[    0.245016] NetLabel: Initializing
[    0.245017] NetLabel:  domain hash size = 128
[    0.245018] NetLabel:  protocols = UNLABELED CIPSOv4
[    0.245030] NetLabel:  unlabeled traffic allowed by default
[    0.245082] HPET: 3 timers in total, 0 timers will be used for per-cpu timer
[    0.245097] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0
[    0.245101] hpet0: 3 comparators, 64-bit 100.000000 MHz counter
[    0.253408] Switching to clocksource kvm-clock
[    0.258121] pnp: PnP ACPI init
[    0.258136] ACPI: bus type PNP registered
[    0.258228] pnp 00:00: Plug and Play ACPI device, IDs PNP0b00 (active)
[    0.258280] pnp 00:01: Plug and Play ACPI device, IDs PNP0303 (active)
[    0.258321] pnp 00:02: Plug and Play ACPI device, IDs PNP0f13 (active)
[    0.258364] pnp 00:03: [dma 2]
[    0.258381] pnp 00:03: Plug and Play ACPI device, IDs PNP0700 (active)
[    0.258480] pnp 00:04: Plug and Play ACPI device, IDs PNP0501 (active)
[    0.258602] pnp 00:05: Plug and Play ACPI device, IDs PNP0103 (active)
[    0.258708] pnp: PnP ACPI: found 6 devices
[    0.258710] ACPI: bus type PNP unregistered
[    0.294865] pci_bus 0000:00: resource 4 [io  0x0000-0x0cf7]
[    0.294868] pci_bus 0000:00: resource 5 [io  0x0d00-0xffff]
[    0.294870] pci_bus 0000:00: resource 6 [mem 0x000a0000-0x000bffff]
[    0.294872] pci_bus 0000:00: resource 7 [mem 0x80000000-0xfebfffff]
[    0.294928] NET: Registered protocol family 2
[    0.295077] TCP established hash table entries: 8192 (order: 4, 65536 bytes)
[    0.295108] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)
[    0.295132] TCP: Hash tables configured (established 8192 bind 8192)
[    0.295164] TCP: reno registered
[    0.295166] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    0.295173] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    0.295229] NET: Registered protocol family 1
[    0.295240] pci 0000:00:00.0: Limiting direct PCI/PCI transfers
[    0.295256] pci 0000:00:01.0: PIIX3: Enabling Passive Release
[    0.295270] pci 0000:00:01.0: Activating ISA DMA hang workarounds
[    0.295448] ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 11
[    0.296138] pci 0000:00:02.0: Boot video device
[    0.296172] PCI: CLS 0 bytes, default 64
[    0.296214] Unpacking initramfs...
[    1.880352] Freeing initrd memory: 16280k freed
[    1.882125] apm: BIOS not found.
[    1.882163] Scanning for low memory corruption every 60 seconds
[    1.882334] audit: initializing netlink socket (disabled)
[    1.882348] type=2000 audit(1376928464.879:1): initialized
[    1.890622] bounce pool size: 64 pages
[    1.890637] HugeTLB registered 4 MB page size, pre-allocated 0 pages
[    1.891711] VFS: Disk quotas dquot_6.5.2
[    1.891747] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    1.891878] msgmni has been set to 1718
[    1.892518] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[    1.892603] io scheduler noop registered
[    1.892607] io scheduler deadline registered
[    1.892636] io scheduler cfq registered (default)
[    1.892754] intel_idle: does not run on family 6 model 2
[    1.892769] GHES: HEST is not enabled!
[    1.892776] isapnp: Scanning for PnP cards...
[    2.252145] isapnp: No Plug & Play device found
[    2.252216] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[    2.273542] 00:04: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[    2.273919] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
[    2.274659] serio: i8042 KBD port at 0x60,0x64 irq 1
[    2.274694] serio: i8042 AUX port at 0x60,0x64 irq 12
[    2.274936] mousedev: PS/2 mouse device common for all mice
[    2.275033] rtc_cmos 00:00: RTC can wake from S4
[    2.275480] rtc_cmos 00:00: rtc core: registered rtc_cmos as rtc0
[    2.275715] rtc_cmos 00:00: alarms up to one day, 114 bytes nvram, hpet irqs
[    2.275747] cpuidle: using governor ladder
[    2.275749] cpuidle: using governor menu
[    2.275751] EFI Variables Facility v0.08 2004-May-17
[    2.275796] drop_monitor: Initializing network drop monitor service
[    2.275936] TCP: cubic registered
[    2.276086] NET: Registered protocol family 10
[    2.276360] NET: Registered protocol family 17
[    2.276377] Key type dns_resolver registered
[    2.276785] Using IPI No-Shortcut mode
[    2.277055] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input0
[    2.277112] PM: Hibernation image not present or could not be loaded.
[    2.277130] registered taskstats version 1
[    2.277773]   Magic number: 9:202:136
[    2.277780] misc autofs: hash matches
[    2.278007] rtc_cmos 00:00: setting system clock to 2013-08-19 16:07:46 UTC (1376928466)
[    2.278357] Freeing unused kernel memory: 572k freed
[    2.278579] Write protecting the kernel text: 4180k
[    2.278656] Write protecting the kernel read-only data: 1300k
[    2.289664] systemd-udevd[56]: starting version 204
[    2.321595] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input1
[    2.321605] ACPI: Power Button [PWRF]
[    2.333638] Linux agpgart interface v0.103
[    2.336640] SCSI subsystem initialized
[    2.338995] ACPI: bus type USB registered
[    2.339013] usbcore: registered new interface driver usbfs
[    2.339020] usbcore: registered new interface driver hub
[    2.339370] ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 10
[    2.339477] ACPI: bus type ATA registered
[    2.339556] libata version 3.00 loaded.
[    2.340379] virtio-pci 0000:00:03.0: setting latency timer to 64
[    2.340542] usbcore: registered new device driver usb
[    2.340949] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    2.341212] uhci_hcd: USB Universal Host Controller Interface driver
[    2.342990] ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 10
[    2.344302] FDC 0 is a S82078B
[    2.344330] virtio-pci 0000:00:06.0: setting latency timer to 64
[    2.346235] virtio-pci 0000:00:07.0: setting latency timer to 64
[    2.347387] ata_piix 0000:00:01.1: version 2.13
[    2.348835] ata_piix 0000:00:01.1: setting latency timer to 64
[    2.349497] scsi0 : ata_piix
[    2.349650] scsi1 : ata_piix
[    2.349700] ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc1c0 irq 14
[    2.349701] ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc1c8 irq 15
[    2.351137] uhci_hcd 0000:00:01.2: setting latency timer to 64
[    2.351146] uhci_hcd 0000:00:01.2: UHCI Host Controller
[    2.351152] uhci_hcd 0000:00:01.2: new USB bus registered, assigned bus number 1
[    2.351257] uhci_hcd 0000:00:01.2: irq 11, io base 0x0000c140
[    2.351428] hub 1-0:1.0: USB hub found
[    2.351431] hub 1-0:1.0: 2 ports detected
[    2.352073] ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 11
[    2.353482] sym0: <895a> rev 0x0 at pci 0000:00:05.0 irq 11
[    2.355767] sym0: No NVRAM, ID 7, Fast-40, LVD, parity checking
[    2.361853] virtio-pci 0000:00:03.0: irq 40 for MSI/MSI-X
[    2.361890] virtio-pci 0000:00:03.0: irq 41 for MSI/MSI-X
[    2.361918] virtio-pci 0000:00:03.0: irq 43 for MSI/MSI-X
[    2.361922] virtio-pci 0000:00:07.0: irq 42 for MSI/MSI-X
[    2.361955] virtio-pci 0000:00:07.0: irq 44 for MSI/MSI-X
[    2.362375] sym0: SCSI BUS has been reset.
[    2.408870] scsi2 : sym-2.2.3
[    2.413614]  vda: vda1 vda2 < vda5 >
[    2.504166] ata2.01: NODEV after polling detection
[    2.504473] ata2.00: ATAPI: QEMU DVD-ROM, 1.4.0, max UDMA/100
[    2.504982] ata2.00: configured for MWDMA2
[    2.508824] scsi 1:0:0:0: CD-ROM            QEMU     QEMU DVD-ROM     1.4. PQ: 0 ANSI: 5
[    2.883460] tsc: Refined TSC clocksource calibration: 3292.540 MHz
[    5.359903] ahci 0000:00:04.0: version 3.0
[    5.360662] ahci 0000:00:04.0: irq 45 for MSI/MSI-X
[    5.361330] ahci 0000:00:04.0: AHCI 0001.0000 32 slots 6 ports 1.5 Gbps 0x3f impl SATA mode
[    5.361334] ahci 0000:00:04.0: flags: ncq only 
[    5.361358] ahci 0000:00:04.0: setting latency timer to 64
[    5.362855] scsi3 : ahci
[    5.363157] scsi4 : ahci
[    5.363322] scsi5 : ahci
[    5.363557] scsi6 : ahci
[    5.363764] scsi7 : ahci
[    5.363930] scsi8 : ahci
[    5.364037] ata3: SATA max UDMA/133 abar m4096@0xfebf4000 port 0xfebf4100 irq 45
[    5.364048] ata4: SATA max UDMA/133 abar m4096@0xfebf4000 port 0xfebf4180 irq 45
[    5.364058] ata5: SATA max UDMA/133 abar m4096@0xfebf4000 port 0xfebf4200 irq 45
[    5.364067] ata6: SATA max UDMA/133 abar m4096@0xfebf4000 port 0xfebf4280 irq 45
[    5.364077] ata7: SATA max UDMA/133 abar m4096@0xfebf4000 port 0xfebf4300 irq 45
[    5.364086] ata8: SATA max UDMA/133 abar m4096@0xfebf4000 port 0xfebf4380 irq 45
[    5.369235] sr0: scsi3-mmc drive: 4x/4x cd/rw xa/form2 tray
[    5.369241] cdrom: Uniform CD-ROM driver Revision: 3.20
[    5.369777] sr 1:0:0:0: Attached scsi CD-ROM sr0
[    5.683594] ata8: SATA link down (SStatus 0 SControl 300)
[    5.687961] ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[    5.688350] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[    5.688494] ata3.00: ATA-7: QEMU HARDDISK, 1.4.0, max UDMA/100
[    5.688499] ata3.00: 11901337600 sectors, multi 16: LBA48 NCQ (depth 31/32)
[    5.688504] ata3.00: applying bridge limits
[    5.688815] ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[    5.689056] ata6: SATA link down (SStatus 0 SControl 300)
[    5.689292] ata7: SATA link down (SStatus 0 SControl 300)
[    5.689405] ata4.00: ATA-7: QEMU HARDDISK, 1.4.0, max UDMA/100
[    5.689411] ata4.00: 11901337600 sectors, multi 16: LBA48 NCQ (depth 31/32)
[    5.689417] ata4.00: applying bridge limits
[    5.689553] ata5.00: ATA-7: QEMU HARDDISK, 1.4.0, max UDMA/100
[    5.689558] ata5.00: 11901337600 sectors, multi 16: LBA48 NCQ (depth 31/32)
[    5.689563] ata5.00: applying bridge limits
[    5.689702] ata3.00: configured for UDMA/100
[    5.689936] ata4.00: configured for UDMA/100
[    5.690123] scsi 3:0:0:0: Direct-Access     ATA      QEMU HARDDISK    1.4. PQ: 0 ANSI: 5
[    5.690527] ata5.00: configured for UDMA/100
[    5.690968] scsi 4:0:0:0: Direct-Access     ATA      QEMU HARDDISK    1.4. PQ: 0 ANSI: 5
[    5.691408] scsi 5:0:0:0: Direct-Access     ATA      QEMU HARDDISK    1.4. PQ: 0 ANSI: 5
[    5.706329] sd 3:0:0:0: [sda] 11901337600 512-byte logical blocks: (6.09 TB/5.54 TiB)
[    5.706483] sd 4:0:0:0: [sdb] 11901337600 512-byte logical blocks: (6.09 TB/5.54 TiB)
[    5.706570] sd 4:0:0:0: [sdb] Write Protect is off
[    5.706575] sd 4:0:0:0: [sdb] Mode Sense: 00 3a 00 00
[    5.706614] sd 3:0:0:0: [sda] Write Protect is off
[    5.706617] sd 3:0:0:0: [sda] Mode Sense: 00 3a 00 00
[    5.706657] sd 4:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    5.706799] sd 3:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    5.707145] sd 5:0:0:0: [sdc] 11901337600 512-byte logical blocks: (6.09 TB/5.54 TiB)
[    5.707232] sd 5:0:0:0: [sdc] Write Protect is off
[    5.707236] sd 5:0:0:0: [sdc] Mode Sense: 00 3a 00 00
[    5.707274] sd 5:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    5.715157]  sdb: sdb1
[    5.715215]  sda: sda1 sda2 sda3
[    5.715550]  sdc: sdc1
[    5.716102] sd 4:0:0:0: [sdb] Attached SCSI disk
[    5.716262] sd 3:0:0:0: [sda] Attached SCSI disk
[    5.716964] sd 5:0:0:0: [sdc] Attached SCSI disk
[    5.875518] ISO 9660 Extensions: RRIP_1991A
[    5.909078] loop: module loaded
[    5.935659] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    5.954038] device-mapper: uevent: version 1.0.3
[    5.954232] device-mapper: ioctl: 4.24.0-ioctl (2013-01-15) initialised: dm-devel@redhat.com
[    5.962231] bio: create slab <bio-1> at 1
[    5.979798] EXT4-fs (dm-0): mounted filesystem without journal. Opts: (null)
[    6.367982] systemd[1]: systemd 204 running in system mode. (+PAM -LIBWRAP -AUDIT -SELINUX -IMA -SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ)
[    6.368016] systemd[1]: Detected virtualization 'kvm'.
[    6.376281] systemd[1]: Set hostname to <archiso>.
[    6.428400] systemd[1]: Starting Forward Password Requests to Wall Directory Watch.
[    6.428495] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[    6.428519] systemd[1]: Starting Remote File Systems.
[    6.429618] systemd[1]: Reached target Remote File Systems.
[    6.429642] systemd[1]: Starting Delayed Shutdown Socket.
[    6.430794] systemd[1]: Listening on Delayed Shutdown Socket.
[    6.430813] systemd[1]: Starting /dev/initctl Compatibility Named Pipe.
[    6.432018] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe.
[    6.432035] systemd[1]: Starting LVM2 metadata daemon socket.
[    6.433084] systemd[1]: Listening on LVM2 metadata daemon socket.
[    6.433102] systemd[1]: Starting Device-mapper event daemon FIFOs.
[    6.434182] systemd[1]: Listening on Device-mapper event daemon FIFOs.
[    6.434236] systemd[1]: Starting Arbitrary Executable File Formats File System Automount Point.
[    6.435587] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point.
[    6.435608] systemd[1]: Starting Encrypted Volumes.
[    6.436616] systemd[1]: Reached target Encrypted Volumes.
[    6.436643] systemd[1]: Starting Dispatch Password Requests to Console Directory Watch.
[    6.436745] systemd[1]: Started Dispatch Password Requests to Console Directory Watch.
[    6.436761] systemd[1]: Starting Paths.
[    6.437719] systemd[1]: Reached target Paths.
[    6.437848] systemd[1]: Starting udev Kernel Socket.
[    6.440680] systemd[1]: Listening on udev Kernel Socket.
[    6.440842] systemd[1]: Starting udev Control Socket.
[    6.441977] systemd[1]: Listening on udev Control Socket.
[    6.442004] systemd[1]: Starting Journal Socket.
[    6.443235] systemd[1]: Listening on Journal Socket.
[    6.444121] systemd[1]: Starting Load Kernel Modules...
[    6.446087] systemd[1]: Mounting POSIX Message Queue File System...
[    6.452313] systemd[1]: Starting udev Coldplug all Devices...
[    6.463186] systemd[1]: Started Set Up Additional Binary Formats.
[    6.463213] systemd[1]: Starting Setup Virtual Console...
[    6.464320] systemd[1]: Mounting Debug File System...
[    6.465024] systemd[1]: Mounting Huge Pages File System...
[    6.484380] systemd[1]: Starting Apply Kernel Variables...
[    6.487238] systemd[1]: Starting Create static device nodes in /dev...
[    6.488300] systemd[1]: Starting Journal Service...
[    6.492394] systemd[1]: Started Journal Service.
[    6.492436] systemd[1]: Starting Swap.
[    6.493121] systemd[1]: Reached target Swap.
[    6.493145] systemd[1]: Mounting Temporary Directory...
[    6.504665] systemd[1]: Started File System Check on Root Device.
[    6.504685] systemd[1]: Starting Remount Root and Kernel File Systems...
[    6.770282] FS-Cache: Loaded
[    6.791770] systemd-udevd[187]: starting version 204
[    6.818666] RPC: Registered named UNIX socket transport module.
[    6.818667] RPC: Registered udp transport module.
[    6.818667] RPC: Registered tcp transport module.
[    6.818668] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    6.907767] FS-Cache: Netfs 'nfs' registered for caching
[    7.253840] microcode: CPU0 sig=0x623, pf=0x0, revision=0x1
[    7.334238] input: PC Speaker as /devices/platform/pcspkr/input/input2
[    7.347274] microcode: CPU1 sig=0x623, pf=0x0, revision=0x1
[    7.347310] microcode: CPU2 sig=0x623, pf=0x0, revision=0x1
[    7.347340] microcode: CPU3 sig=0x623, pf=0x0, revision=0x1
[    7.350125] microcode: Microcode Update Driver: v2.00 <tigran@aivazian.fsnet.co.uk>, Peter Oruba
[    7.560486] piix4_smbus 0000:00:01.3: SMBus Host Controller at 0xb100, revision 0
[    7.759967] [drm] Initialized drm 1.1.0 20060810
[    7.849035] [TTM] Zone  kernel: Available graphics memory: 440226 kiB
[    7.849038] [TTM] Zone highmem: Available graphics memory: 1034146 kiB
[    7.849040] [TTM] Initializing pool allocator
[    7.872562] [drm] fb mappable at 0x0
[    7.872566] [drm] vram aper at 0x0
[    7.872567] [drm] size 0
[    7.872568] [drm] fb depth is 24
[    7.872569] [drm]    pitch is 3840
[    7.872647] fbcon: cirrusdrmfb (fb0) is primary device
[    7.904473] psmouse serio1: hgpk: ID: 10 00 64
[    7.909114] Console: switching to colour frame buffer device 160x64
[    7.924861] cirrus 0000:00:02.0: fb0: cirrusdrmfb frame buffer device
[    7.924863] cirrus 0000:00:02.0: registered panic notifier
[    7.924869] [drm] Initialized cirrus 1.0.0 20110418 for 0000:00:02.0 on minor 0
[    8.225879] bio: create slab <bio-2> at 2
[    8.309369] xor: measuring software checksum speed
[    8.340071]    pIII_sse  : 12313.200 MB/sec
[    8.353096] input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input3
[    8.373362]    prefetch64-sse: 18412.800 MB/sec
[    8.373364] xor: using function: prefetch64-sse (18412.800 MB/sec)
[    8.446693] raid6: mmxx1     3220 MB/s
[    8.503360] raid6: mmxx2     3527 MB/s
[    8.560035] raid6: sse1x1    2778 MB/s
[    8.616700] raid6: sse1x2    3494 MB/s
[    8.673355] raid6: sse2x1    5658 MB/s
[    8.730023] raid6: sse2x2    7134 MB/s
[    8.730026] raid6: using algorithm sse2x2 (7134 MB/s)
[    8.730028] raid6: using intx1 recovery algorithm
[    8.751405] Btrfs loaded
[    8.751977] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/dm-3
[   45.905228] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/mapper/main--storage--vg-root
[   45.907315] btrfs: enabling auto recovery
[   45.907322] btrfs: disk space caching is enabled
[   45.914105] btrfs: unable to find logical 1781900460032 len 4096
[   45.914275] ------------[ cut here ]------------
[   45.914406] kernel BUG at fs/btrfs/volumes.c:4417!
[   45.914489] invalid opcode: 0000 [#1] PREEMPT SMP 
[   45.914588] Modules linked in: btrfs raid6_pq crc32c libcrc32c zlib_deflate xor cirrus ttm drm_kms_helper drm syscopyarea sysfillrect sysimgblt kvm_intel kvm i2c_piix4 i2c_core psmouse processor pcspkr serio_raw evdev microcode nfs lockd sunrpc fscache ext4 crc16 mbcache jbd2 dm_snapshot dm_mod squashfs loop isofs sd_mod sr_mod cdrom ata_generic pata_acpi virtio_blk virtio_balloon virtio_net ahci libahci sym53c8xx scsi_transport_spi uhci_hcd ehci_hcd ata_piix virtio_pci usbcore usb_common libata scsi_mod intel_agp intel_gtt agpgart floppy button
[   45.915599] Pid: 510, comm: mount Not tainted 3.9.8-1-ARCH #1 Bochs Bochs
[   45.915701] EIP: 0060:[<f9d0f4fe>] EFLAGS: 00010282 CPU: 3
[   45.915805] EIP is at __btrfs_map_block+0x13de/0x13f0 [btrfs]
[   45.915936] EAX: 00000034 EBX: f6d8f0cc ECX: 00000000 EDX: f57ff9a0
[   45.916033] ESI: 00000000 EDI: 0000019e EBP: f6fb9bc4 ESP: f6fb9afc
[   45.916129]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[   45.916217] CR0: 8005003b CR2: b7717ce0 CR3: 3413c000 CR4: 000006d0
[   45.916320] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[   45.916419] DR6: ffff0ff0 DR7: 00000400
[   45.916491] Process mount (pid: 510, ti=f6fb8000 task=f6eb1b30 task.ti=f6fb8000)
[   45.916597] Stack:
[   45.916648]  f9d5ec00 e18b4000 0000019e 00001000 00000000 000028d0 fa83b2da 00000000
[   45.916810]  0000b800 0000b800 00000000 00000001 f6fb9b5c c0230185 00000000 00000008
[   45.916962]  f9d03bde c01f4683 00000080 00011220 f38a3000 f6d8f000 00000000 00000286
[   45.917115] Call Trace:
[   45.917188]  [<c0230185>] ? kmem_cache_alloc+0x65/0x1b0
[   45.917188]  [<f9d03bde>] ? tree_insert+0x4e/0x80 [btrfs]
[   45.917188]  [<c01f4683>] ? mempool_alloc_slab+0x13/0x20
[   45.917188]  [<f83e6860>] ? dm_target_exit+0x20/0x20 [dm_mod]
[   45.917188]  [<f83e24b1>] ? dm_merge_bvec+0x91/0xf0 [dm_mod]
[   45.917188]  [<f83e6860>] ? dm_target_exit+0x20/0x20 [dm_mod]
[   45.917188]  [<f83e2420>] ? dm_get_live_table+0x40/0x40 [dm_mod]
[   45.917188]  [<c0271bc4>] ? __bio_add_page+0xd4/0x200
[   45.917188]  [<c0272430>] ? bio_alloc_bioset+0x130/0x180
[   45.917188]  [<f83e2420>] ? dm_get_live_table+0x40/0x40 [dm_mod]
[   45.917188]  [<f9d14e98>] btrfs_map_bio+0x78/0x450 [btrfs]
[   45.917188]  [<f9d0868b>] ? submit_extent_page.isra.38+0xeb/0x1d0 [btrfs]
[   45.917188]  [<f9d06f60>] ? test_range_bit+0x80/0x180 [btrfs]
[   45.917188]  [<f9d08c67>] ? __extent_read_full_page+0x4f7/0x7f0 [btrfs]
[   45.917188]  [<f9ce1e79>] ? btrfs_bio_wq_end_io+0x29/0x70 [btrfs]
[   45.917188]  [<f9ce20aa>] btree_submit_bio_hook+0x5a/0x100 [btrfs]
[   45.917188]  [<f9ce2050>] ? btrfs_wq_submit_bio+0x170/0x170 [btrfs]
[   45.917188]  [<f9d03c90>] submit_one_bio+0x80/0xb0 [btrfs]
[   45.917188]  [<f9ce2050>] ? btrfs_wq_submit_bio+0x170/0x170 [btrfs]
[   45.917188]  [<f9d0b848>] read_extent_buffer_pages+0x1f8/0x2b0 [btrfs]
[   45.917188]  [<f9ce1af8>] btree_read_extent_buffer_pages.constprop.52+0xc8/0x140 [btrfs]
[   45.917188]  [<f9cdff10>] ? run_one_async_done+0xd0/0xd0 [btrfs]
[   45.917188]  [<f9ce23f7>] read_tree_block+0x47/0x50 [btrfs]
[   45.917188]  [<f9ce5f5c>] open_ctree+0x13bc/0x1b60 [btrfs]
[   45.917188]  [<c030b163>] ? strlcpy+0x33/0x50
[   45.917188]  [<f9cbe89b>] btrfs_mount+0x77b/0x8c0 [btrfs]
[   45.917188]  [<c0231ef0>] ? __kmalloc_track_caller+0x80/0x1d0
[   45.917188]  [<c0246351>] mount_fs+0x31/0x180
[   45.917188]  [<c020e3df>] ? __alloc_percpu+0xf/0x20
[   45.917188]  [<c025c6b5>] vfs_kern_mount+0x45/0xc0
[   45.917188]  [<c025e402>] do_mount+0x1e2/0x840
[   45.917188]  [<c025e10f>] ? copy_mount_options+0x2f/0x100
[   45.917188]  [<c025eacb>] sys_mount+0x6b/0xa0
[   45.917188]  [<c050d54b>] syscall_call+0x7/0xb
[   45.917188] Code: ff 8b 45 10 8b 50 04 8b 00 c7 04 24 00 ec d5 f9 89 54 24 10 8b 55 0c 89 44 24 0c 8b 45 08 89 54 24 08 89 44 24 04 e8 4b 6e 7f c6 <0f> 0b bb f4 ff ff ff e9 1b f4 ff ff 8d b6 00 00 00 00 55 89 e5
[   45.917188] EIP: [<f9d0f4fe>] __btrfs_map_block+0x13de/0x13f0 [btrfs] SS:ESP 0068:f6fb9afc
[   45.961103] ---[ end trace 9d69bb5afeaa2a52 ]---
[  110.572033] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/mapper/main--storage--vg-root
[ 5010.523571] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/mapper/main--storage--vg-root

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Mitch Harder]

On Thu, Aug 22, 2013 at 1:47 AM, Nicholas Lee <email@nickle.es> wrote:

> [   45.914275] ------------[ cut here ]------------
> [   45.914406] kernel BUG at fs/btrfs/volumes.c:4417!
> [   45.914489] invalid opcode: 0000 [#1] PREEMPT SMP

I can't say if this will fix your problem or not, but the 3.10.x
kernel has a patch to pass this error back instead of halting with a
BUG() at this point.

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Nicholas Lee]

After updating the kernel and using btrfs-progs-git from the AUR, I'm now getting this output. Does this yield any new insight?

[  473.305408] btrfs: failed to read tree root on dm-2
[  473.305555] BTRFS critical (device dm-2): unable to find logical 1781900460032 len 4096
[  473.305591] BTRFS emergency (device dm-2): No mapping for 1781900460032-1781900464128


On 22.08.2013, at 10:09, Mitch Harder <mitch.harder@sabayonlinux.org> wrote:

> On Thu, Aug 22, 2013 at 1:47 AM, Nicholas Lee <email@nickle.es> wrote:
> 
>> [   45.914275] ------------[ cut here ]------------
>> [   45.914406] kernel BUG at fs/btrfs/volumes.c:4417!
>> [   45.914489] invalid opcode: 0000 [#1] PREEMPT SMP
> 
> I can't say if this will fix your problem or not, but the 3.10.x
> kernel has a patch to pass this error back instead of halting with a
> BUG() at this point.

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Nicholas Lee]

Full pastebin here: http://cwillu.com:8080/96.245.194.45#6

[   9.213212] Btrfs loaded
[    9.245673] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/dm-1
[  102.886834] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/mapper/main--storage--vg-root
[  102.888348] btrfs: enabling auto recovery
[  102.888354] btrfs: disabling disk space caching
[  102.888357] btrfs: disabling disk space caching
[  102.911068] BTRFS critical (device dm-1): unable to find logical 1781900460032 len 4096
[  102.911103] BTRFS emergency (device dm-1): No mapping for 1781900460032-1781900464128

[  102.911108] btrfs: failed to read tree root on dm-1
[  102.911186] BTRFS critical (device dm-1): unable to find logical 1781900460032 len 4096
[  102.911217] BTRFS emergency (device dm-1): No mapping for 1781900460032-1781900464128

[  102.911222] btrfs: failed to read tree root on dm-1
[  102.911235] BTRFS critical (device dm-1): unable to find logical 1198824710144 len 4096
[  102.911240] BTRFS emergency (device dm-1): No mapping for 1198824710144-1198824714240

[  102.911243] btrfs: failed to read tree root on dm-1
[  102.911255] BTRFS critical (device dm-1): unable to find logical 1198518919168 len 4096
[  102.911286] BTRFS emergency (device dm-1): No mapping for 1198518919168-1198518923264

[  102.911290] btrfs: failed to read tree root on dm-1
[  102.911302] BTRFS critical (device dm-1): unable to find logical 582755782656 len 4096
[  102.911308] BTRFS emergency (device dm-1): No mapping for 582755782656-582755786752

[  102.911311] btrfs: failed to read tree root on dm-1
[  102.986797] btrfs: open_ctree failed


On 22.08.2013, at 15:23, Nicholas Lee <email@nickle.es> wrote:

> After updating the kernel and using btrfs-progs-git from the AUR, I'm now getting this output. Does this yield any new insight?
> 
> [  473.305408] btrfs: failed to read tree root on dm-2
> [  473.305555] BTRFS critical (device dm-2): unable to find logical 1781900460032 len 4096
> [  473.305591] BTRFS emergency (device dm-2): No mapping for 1781900460032-1781900464128
> 
> 
> On 22.08.2013, at 10:09, Mitch Harder <mitch.harder@sabayonlinux.org> wrote:
> 
>> On Thu, Aug 22, 2013 at 1:47 AM, Nicholas Lee <email@nickle.es> wrote:
>> 
>>> [   45.914275] ------------[ cut here ]------------
>>> [   45.914406] kernel BUG at fs/btrfs/volumes.c:4417!
>>> [   45.914489] invalid opcode: 0000 [#1] PREEMPT SMP
>> 
>> I can't say if this will fix your problem or not, but the 3.10.x
>> kernel has a patch to pass this error back instead of halting with a
>> BUG() at this point.
> 

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

Non-expert on btrfs errors, so hopefully someone else will still reply with recovery advice. I have some foundational questions on the setup that may relate, if you don't already know what precipitated this failure:


1.
You said it's md raid5, but I see /dev/mapper/main--storage--vg-root and dm-1 or dm-2, so I wonder if this is md raid with LVM on top; or if this is LVM raid5 (which directly implements raid5 at LV level, without mdadm, but does use md code underneath)?

2.
In one dmesg I see /dev/dm-2 referenced with errors, and in another /dev/dm-1. Is it actually the same btrfs volume, and if so I wonder why it's sometimes being mapped to a difference dm device?

3.
If it's an md device, when was the last time a scrub check was run?
echo check > /sys/block/mdX/md/sync_action
then after that completes:
cat /sys/block/mdX/mismatch_cnt

Or if LVM raid5, I think this is only recently added:
http://www.redhat.com/archives/lvm-devel/2013-April/msg00042.html

4.
smartctl -x for each drive; are there any indications of reallocated sectors, pending sectors, bad block, ECC error, CRC or UDMA error? Also included in the above command should return the SCT Error Recovery Control value for each drive, what's that value?

5.
What is returned for any one of the drives:

cat /sys/block/sdX/device/timeout

Thanks,

Chris Murphy


On Aug 22, 2013, at 1:38 PM, Nicholas Lee <email@nickle.es> wrote:

> Full pastebin here: http://cwillu.com:8080/96.245.194.45#6
> 
> [   9.213212] Btrfs loaded
> [    9.245673] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/dm-1
> [  102.886834] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/mapper/main--storage--vg-root
> [  102.888348] btrfs: enabling auto recovery
> [  102.888354] btrfs: disabling disk space caching
> [  102.888357] btrfs: disabling disk space caching
> [  102.911068] BTRFS critical (device dm-1): unable to find logical 1781900460032 len 4096
> [  102.911103] BTRFS emergency (device dm-1): No mapping for 1781900460032-1781900464128
> 
> [  102.911108] btrfs: failed to read tree root on dm-1
> [  102.911186] BTRFS critical (device dm-1): unable to find logical 1781900460032 len 4096
> [  102.911217] BTRFS emergency (device dm-1): No mapping for 1781900460032-1781900464128
> 
> [  102.911222] btrfs: failed to read tree root on dm-1
> [  102.911235] BTRFS critical (device dm-1): unable to find logical 1198824710144 len 4096
> [  102.911240] BTRFS emergency (device dm-1): No mapping for 1198824710144-1198824714240
> 
> [  102.911243] btrfs: failed to read tree root on dm-1
> [  102.911255] BTRFS critical (device dm-1): unable to find logical 1198518919168 len 4096
> [  102.911286] BTRFS emergency (device dm-1): No mapping for 1198518919168-1198518923264
> 
> [  102.911290] btrfs: failed to read tree root on dm-1
> [  102.911302] BTRFS critical (device dm-1): unable to find logical 582755782656 len 4096
> [  102.911308] BTRFS emergency (device dm-1): No mapping for 582755782656-582755786752
> 
> [  102.911311] btrfs: failed to read tree root on dm-1
> [  102.986797] btrfs: open_ctree failed
> 
> 
> On 22.08.2013, at 15:23, Nicholas Lee <email@nickle.es> wrote:
> 
>> After updating the kernel and using btrfs-progs-git from the AUR, I'm now getting this output. Does this yield any new insight?
>> 
>> [  473.305408] btrfs: failed to read tree root on dm-2
>> [  473.305555] BTRFS critical (device dm-2): unable to find logical 1781900460032 len 4096
>> [  473.305591] BTRFS emergency (device dm-2): No mapping for 1781900460032-1781900464128
>> 
>> 
>> On 22.08.2013, at 10:09, Mitch Harder <mitch.harder@sabayonlinux.org> wrote:
>> 
>>> On Thu, Aug 22, 2013 at 1:47 AM, Nicholas Lee <email@nickle.es> wrote:
>>> 
>>>> [   45.914275] ------------[ cut here ]------------
>>>> [   45.914406] kernel BUG at fs/btrfs/volumes.c:4417!
>>>> [   45.914489] invalid opcode: 0000 [#1] PREEMPT SMP
>>> 
>>> I can't say if this will fix your problem or not, but the 3.10.x
>>> kernel has a patch to pass this error back instead of halting with a
>>> BUG() at this point.
>> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Duncan]

Nicholas Lee posted on Thu, 22 Aug 2013 02:47:38 -0400 as excerpted:

> Problem: My filesystem is screwed up, and I can't mount it at all right
> now. In the logs, the problem begins around 45s.

> Adding insult to injury, this occurred right as I began the initial
> backup to another system with rsync. :(

> I would be seriously grateful to anyone that can figure out a way to
> mount/fix this partition, and I'd be willing to send some bitcoin

Not to add insult to injury, but for future reference anyway, you /are/ 
aware that btrfs is still marked experimental both in the kernel btrfs 
option description and on the btrfs wiki[1], and that as such, anything 
you put on it should be considered subject to loss, basically throw-away 
data that you don't care about losing either because you have multiple 
backups (on rather less developmental-stage stable filesystems), or 
because it really is throw-away data, and backups would be overkill.

I know you were just starting that backup, but the fact that you're 
willing to throw some bitcoin at recovery indicates that you 
/already/ had valuable data on the filesystem, that should have already 
been restoreable from (tested) backup.  Alternatively, perhaps btrfs 
simply isn't an appropriate choice of filesystem for you at this point, 
because it /is/ still considered experimental.  Maybe in a year or two, 
sometime after that experimental label comes off, depending on how 
conservative you actually need to be with your data.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 22, 2013, at 4:58 PM, Chris Murphy <lists@colorremedies.com> wrote:
> 1
> 2
> 3
> 4
> 5

6. What was the mkfs.btrfs command used? In particular are you certain the metadata profile is default (DUP)?

7. If you have a very recent btrfs-progs (few months at most), or better if you can build from btrfs-next, it may be worth running btrfsck *without* the repair option, to see what it has to say about the situation.

Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Nicholas Lee]

1. It's md-raid, with an lvm on top, and this is running in a virtual machine with lvm also enabled. 
2. Originally, I was working from the Arch LiveCD, but I later created another disk to install ArchBang to.
3. I'm waiting for the check to complete.
4. SMART comes up clean

smartctl -x /dev/sdg | grep SCT
SCT capabilities:              (0x003d) SCT Status supported.
                                        SCT Error Recovery Control supported.
                                        SCT Feature Control supported.
                                        SCT Data Table supported.
GP/S  Log at address 0xe0 has    1 sectors [SCT Command/Status]
GP/S  Log at address 0xe1 has    1 sectors [SCT Data Transfer]
SCT Status Version:                  3
SCT Version (vendor specific):       256 (0x0100)
SCT Support Level:                   1
SCT Temperature History Version:     2
SCT Error Recovery Control:

5. It returns a value of 30.

I'm running chunk-recover, but I'm going to let it write anything. I figure it'll take a while for it to scan, given the large size of the drive. 


On 22.08.2013, at 18:58, Chris Murphy <lists@colorremedies.com> wrote:

> Non-expert on btrfs errors, so hopefully someone else will still reply with recovery advice. I have some foundational questions on the setup that may relate, if you don't already know what precipitated this failure:
> 
> 
> 1.
> You said it's md raid5, but I see /dev/mapper/main--storage--vg-root and dm-1 or dm-2, so I wonder if this is md raid with LVM on top; or if this is LVM raid5 (which directly implements raid5 at LV level, without mdadm, but does use md code underneath)?
> 
> 2.
> In one dmesg I see /dev/dm-2 referenced with errors, and in another /dev/dm-1. Is it actually the same btrfs volume, and if so I wonder why it's sometimes being mapped to a difference dm device?
> 
> 3.
> If it's an md device, when was the last time a scrub check was run?
> echo check > /sys/block/mdX/md/sync_action
> then after that completes:
> cat /sys/block/mdX/mismatch_cnt
> 
> Or if LVM raid5, I think this is only recently added:
> http://www.redhat.com/archives/lvm-devel/2013-April/msg00042.html
> 
> 4.
> smartctl -x for each drive; are there any indications of reallocated sectors, pending sectors, bad block, ECC error, CRC or UDMA error? Also included in the above command should return the SCT Error Recovery Control value for each drive, what's that value?
> 
> 5.
> What is returned for any one of the drives:
> 
> cat /sys/block/sdX/device/timeout
> 
> Thanks,
> 
> Chris Murphy
> 
> 
> On Aug 22, 2013, at 1:38 PM, Nicholas Lee <email@nickle.es> wrote:
> 
>> Full pastebin here: http://cwillu.com:8080/96.245.194.45#6
>> 
>> [   9.213212] Btrfs loaded
>> [    9.245673] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/dm-1
>> [  102.886834] device fsid 2ffb2450-f74f-4cfb-a3be-bb5e3c6d32ec devid 1 transid 23568 /dev/mapper/main--storage--vg-root
>> [  102.888348] btrfs: enabling auto recovery
>> [  102.888354] btrfs: disabling disk space caching
>> [  102.888357] btrfs: disabling disk space caching
>> [  102.911068] BTRFS critical (device dm-1): unable to find logical 1781900460032 len 4096
>> [  102.911103] BTRFS emergency (device dm-1): No mapping for 1781900460032-1781900464128
>> 
>> [  102.911108] btrfs: failed to read tree root on dm-1
>> [  102.911186] BTRFS critical (device dm-1): unable to find logical 1781900460032 len 4096
>> [  102.911217] BTRFS emergency (device dm-1): No mapping for 1781900460032-1781900464128
>> 
>> [  102.911222] btrfs: failed to read tree root on dm-1
>> [  102.911235] BTRFS critical (device dm-1): unable to find logical 1198824710144 len 4096
>> [  102.911240] BTRFS emergency (device dm-1): No mapping for 1198824710144-1198824714240
>> 
>> [  102.911243] btrfs: failed to read tree root on dm-1
>> [  102.911255] BTRFS critical (device dm-1): unable to find logical 1198518919168 len 4096
>> [  102.911286] BTRFS emergency (device dm-1): No mapping for 1198518919168-1198518923264
>> 
>> [  102.911290] btrfs: failed to read tree root on dm-1
>> [  102.911302] BTRFS critical (device dm-1): unable to find logical 582755782656 len 4096
>> [  102.911308] BTRFS emergency (device dm-1): No mapping for 582755782656-582755786752
>> 
>> [  102.911311] btrfs: failed to read tree root on dm-1
>> [  102.986797] btrfs: open_ctree failed
>> 
>> 
>> On 22.08.2013, at 15:23, Nicholas Lee <email@nickle.es> wrote:
>> 
>>> After updating the kernel and using btrfs-progs-git from the AUR, I'm now getting this output. Does this yield any new insight?
>>> 
>>> [  473.305408] btrfs: failed to read tree root on dm-2
>>> [  473.305555] BTRFS critical (device dm-2): unable to find logical 1781900460032 len 4096
>>> [  473.305591] BTRFS emergency (device dm-2): No mapping for 1781900460032-1781900464128
>>> 
>>> 
>>> On 22.08.2013, at 10:09, Mitch Harder <mitch.harder@sabayonlinux.org> wrote:
>>> 
>>>> On Thu, Aug 22, 2013 at 1:47 AM, Nicholas Lee <email@nickle.es> wrote:
>>>> 
>>>>> [   45.914275] ------------[ cut here ]------------
>>>>> [   45.914406] kernel BUG at fs/btrfs/volumes.c:4417!
>>>>> [   45.914489] invalid opcode: 0000 [#1] PREEMPT SMP
>>>> 
>>>> I can't say if this will fix your problem or not, but the 3.10.x
>>>> kernel has a patch to pass this error back instead of halting with a
>>>> BUG() at this point.
>>> 
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> Chris Murphy
> 

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 22, 2013, at 6:59 PM, Nicholas Lee <email@nickle.es> wrote:
> 
> smartctl -x /dev/sdg | grep SCT

The grep filtered the current read/write values, try this:

smartctl -l scterc /dev/sdg


If it's higher than 300(30.0 seconds) then you should change it:

smartctl -l scterc,70,70 /dev/sdX

for all drives. And then I'd filter through dmesg to see if you have any PHY or read errors or ATA reset messages.


Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Duncan]

Duncan posted on Thu, 22 Aug 2013 23:53:28 +0000 as excerpted:

> btrfs wiki[1]

[1] https://btrfs.wiki.kernel.org/


-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Nicholas Lee]

Good news everyone! I got this to mount again using btrfs chunk-recover on the partition! It took around a day for it to run the initial chunk recovery scan (iotop showed that I was limited by disk throughput) and another three hours for the actual chunk recovery (iops limited).

Hopefully someone out there that runs into a similar issue will end up finding this!

On 22.08.2013, at 21:36, Nicholas Lee <email@nickle.es> wrote:

> 6. I don't know off the top of my head, but I'd assume it was the default. It was created by Ubuntu Server Edition
> 7.  I installed btrfs-progs-git from the AUR, and it (pretty much instantly) returns the following error: 
> 
> sudo btrfsck /dev/main-storage-vg/root 
> Couldn't map the block 1781900460032
> btrfsck: volumes.c:1020: btrfs_num_copies: Assertion `!(ce->start > logical || ce->start + ce->size < logical)' failed.
> 
> If chunk-recover finds anything, I'll let you guys know. (It's still running, and I have yet to write anything.)
> 
> 
> On 22.08.2013, at 20:58, Chris Murphy <lists@colorremedies.com> wrote:
>> 
>> 6. What was the mkfs.btrfs command used? In particular are you certain the metadata profile is default (DUP)?
>> 
>> 7. If you have a very recent btrfs-progs (few months at most), or better if you can build from btrfs-next, it may be worth running btrfsck *without* the repair option, to see what it has to say about the situation.
> 

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 26, 2013, at 11:26 AM, Nicholas Lee <email@nickle.es> wrote:

> Good news everyone! I got this to mount again using btrfs chunk-recover on the partition! It took around a day for it to run the initial chunk recovery scan (iotop showed that I was limited by disk throughput) and another three hours for the actual chunk recovery (iops limited).

Interesting. I also found this:
http://permalink.gmane.org/gmane.comp.file-systems.btrfs/26748

I wonder, what in dmesg indicates that the chunk tree is broken, and thus chunk-recover should be used? Or would a btrfsck without repair indicate it? 


Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 26, 2013, at 11:41 AM, Nick Lee <email@nickle.es> wrote:

> There was a discussion on IRC a few days ago that the problem with the tree root's bloco was likely the result of either an issue with the disk itself, or the chunk tree/logical mappings. I ran the chunk recover, looked over the errors it found, and hit write. (If it failed, I was going to run something photorec, loss of organization as a side effect.)
> 
> I can write something more clear after my flight lands tomorrow if you want.

I'm just curious about when to use various techniques: -o recovery, btrfsck, chunk-recover, zero log.


Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Hugo Mills]

[-- Attachment #1: Type: text/plain, Size: 2008 bytes --]

On Mon, Aug 26, 2013 at 01:10:54PM -0600, Chris Murphy wrote:
> 
> On Aug 26, 2013, at 11:41 AM, Nick Lee <email@nickle.es> wrote:
> 
> > There was a discussion on IRC a few days ago that the problem with the tree root's bloco was likely the result of either an issue with the disk itself, or the chunk tree/logical mappings. I ran the chunk recover, looked over the errors it found, and hit write. (If it failed, I was going to run something photorec, loss of organization as a side effect.)
> > 
> > I can write something more clear after my flight lands tomorrow if you want.

> I'm just curious about when to use various techniques: -o recovery,
> btrfsck, chunk-recover, zero log.

   Let's assume that you don't have a physical device failure (which
is a different set of tools -- mount -odegraded, btrfs dev del
missing).

   First thing to do is to take a btrfs-image -c9 -t4 of the
filesystem, and keep a copy of the output to show josef. :)

   Then start with -orecovery and -oro,recovery for pretty much
anything.

   If those fail, then look in dmesg for errors relating to the log
tree -- if that's corrupt and can't be read (or causes a crash), use
btrfs-zero-log.

   If there's problems with the chunk tree -- the only one I've seen
recently was reporting something like "can't map address" -- then
chunk-recover may be of use.

   After that, btrfsck is probably the next thing to try. If options
-s1, -s2, -s3 have any success, then btrfs-select-super will help by
replacing the superblock with one that works. If that's not going to
be useful, fall back to btrfsck --repair.

   Finally, btrfsck --repair --init-extent-tree may be necessary if
there's a damaged extent tree. Finally, if you've got corruption in
the checksums, there's --init-csum-tree.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
      --- Try everything once,  except incest and folk-dancing. ---      

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Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 26, 2013, at 1:31 PM, Hugo Mills <hugo@carfax.org.uk> wrote:
> 
>   Let's assume that you don't have a physical device failure (which
> is a different set of tools -- mount -odegraded, btrfs dev del
> missing).
> 
>   First thing to do is to take a btrfs-image -c9 -t4 of the
> filesystem, and keep a copy of the output to show josef. :)
> 
>   Then start with -orecovery and -oro,recovery for pretty much
> anything.
> 
>   If those fail, then look in dmesg for errors relating to the log
> tree -- if that's corrupt and can't be read (or causes a crash), use
> btrfs-zero-log.
> 
>   If there's problems with the chunk tree -- the only one I've seen
> recently was reporting something like "can't map address" -- then
> chunk-recover may be of use.
> 
>   After that, btrfsck is probably the next thing to try. If options
> -s1, -s2, -s3 have any success, then btrfs-select-super will help by
> replacing the superblock with one that works. If that's not going to
> be useful, fall back to btrfsck --repair.
> 
>   Finally, btrfsck --repair --init-extent-tree may be necessary if
> there's a damaged extent tree. Finally, if you've got corruption in
> the checksums, there's --init-csum-tree.

This is helpful. Thanks.

Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Zach Brown]

>    If those fail, then look in dmesg for errors relating to the log
> tree -- if that's corrupt and can't be read (or causes a crash), use
> btrfs-zero-log.

In a bit of a tangent:

btrfs-zero-log throws away data that fsync/sync could have previously
claimed was stable on disk.

Given how often this is thrown around as a solution to a broken
partition, should the tool jump up and down and make it clear that it's
about to roll the file system back?  This seems like relevant
information.

Right now, as far as I can tell, it's completely undocumented and
silent.

- z

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 29, 2013, at 11:35 AM, Zach Brown <zab@redhat.com> wrote:

>>   If those fail, then look in dmesg for errors relating to the log
>> tree -- if that's corrupt and can't be read (or causes a crash), use
>> btrfs-zero-log.
> 
> In a bit of a tangent:
> 
> btrfs-zero-log throws away data that fsync/sync could have previously
> claimed was stable on disk.
> 
> Given how often this is thrown around as a solution to a broken
> partition, should the tool jump up and down and make it clear that it's
> about to roll the file system back?  This seems like relevant
> information.
> 
> Right now, as far as I can tell, it's completely undocumented and
> silent.

Yes, I think it helps remove some burden on the list answering questions about a tool that doesn't have any documentation, to have a warning.

How much longer will btrfs-zero-log be needed? If whatever it's doing isn't obviated by future improvements to btrfsck, and this sort of big hammer approach is still needed in some worse case scenarios, then it probably hurts no one to flag the user with essentially how you described it. I think documentation is a greater burden to create, and less likely to be consulted.

"Proceeding will roll back the file system to a previous state, and may cause the loss of successfully written data. Proceed? (Y/N)"

Alternative language could include a suggestion or reminder of what should be tried before proceeding, if applicable.



Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Hugo Mills]

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On Thu, Aug 29, 2013 at 01:37:51PM -0600, Chris Murphy wrote:
> 
> On Aug 29, 2013, at 11:35 AM, Zach Brown <zab@redhat.com> wrote:
> 
> >>   If those fail, then look in dmesg for errors relating to the log
> >> tree -- if that's corrupt and can't be read (or causes a crash), use
> >> btrfs-zero-log.
> > 
> > In a bit of a tangent:
> > 
> > btrfs-zero-log throws away data that fsync/sync could have previously
> > claimed was stable on disk.
> > 
> > Given how often this is thrown around as a solution to a broken
> > partition, should the tool jump up and down and make it clear that it's
> > about to roll the file system back?  This seems like relevant
> > information.
> > 
> > Right now, as far as I can tell, it's completely undocumented and
> > silent.
> 
> Yes, I think it helps remove some burden on the list answering questions about a tool that doesn't have any documentation, to have a warning.
> 
> How much longer will btrfs-zero-log be needed? If whatever it's doing isn't obviated by future improvements to btrfsck, and this sort of big hammer approach is still needed in some worse case scenarios, then it probably hurts no one to flag the user with essentially how you described it. I think documentation is a greater burden to create, and less likely to be consulted.
> 
> "Proceeding will roll back the file system to a previous state, and may cause the loss of successfully written data. Proceed? (Y/N)"

   "... the loss of up to the last 30 seconds of successfully written data."

   Give the user enough information to make a sensible decision.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
        --- emacs:  Eighty Megabytes And Constantly Swapping. ---        

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Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 29, 2013, at 1:40 PM, Hugo Mills <hugo@carfax.org.uk> wrote:

> On Thu, Aug 29, 2013 at 01:37:51PM -0600, Chris Murphy wrote:
>> 
>> "Proceeding will roll back the file system to a previous state, and may cause the loss of successfully written data. Proceed? (Y/N)"
> 
>   "... the loss of up to the last 30 seconds of successfully written data."
> 
>   Give the user enough information to make a sensible decision.

Certainly, if known for sure it won't be more than 30 seconds?



Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Hugo Mills]

[-- Attachment #1: Type: text/plain, Size: 978 bytes --]

On Thu, Aug 29, 2013 at 01:44:54PM -0600, Chris Murphy wrote:
> 
> On Aug 29, 2013, at 1:40 PM, Hugo Mills <hugo@carfax.org.uk> wrote:
> 
> > On Thu, Aug 29, 2013 at 01:37:51PM -0600, Chris Murphy wrote:
> >> 
> >> "Proceeding will roll back the file system to a previous state, and may cause the loss of successfully written data. Proceed? (Y/N)"
> > 
> >   "... the loss of up to the last 30 seconds of successfully written data."
> > 
> >   Give the user enough information to make a sensible decision.
> 
> Certainly, if known for sure it won't be more than 30 seconds?

   Mmm... it'll depend on the setting of the commit period, which up
until a couple of weeks ago was always 30s, but someone posted a patch
to give it a config knob...

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
        --- emacs:  Eighty Megabytes And Constantly Swapping. ---        

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Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 29, 2013, at 1:53 PM, Hugo Mills <hugo@carfax.org.uk> wrote:

> On Thu, Aug 29, 2013 at 01:44:54PM -0600, Chris Murphy wrote:
>> 
>> Certainly, if known for sure it won't be more than 30 seconds?
> 
>   Mmm... it'll depend on the setting of the commit period, which up
> until a couple of weeks ago was always 30s, but someone posted a patch
> to give it a config knob…



"Proceeding will roll back the file system to a previous state, and may cause the loss of successfully written data since the last commit period (30 seconds by default). Proceed? (Y/N)"


Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Chris Murphy]

On Aug 29, 2013, at 2:19 PM, Chris Murphy <lists@colorremedies.com> wrote:

> 
> On Aug 29, 2013, at 1:53 PM, Hugo Mills <hugo@carfax.org.uk> wrote:
> 
>> On Thu, Aug 29, 2013 at 01:44:54PM -0600, Chris Murphy wrote:
>>> 
>>> Certainly, if known for sure it won't be more than 30 seconds?
>> 
>>  Mmm... it'll depend on the setting of the commit period, which up
>> until a couple of weeks ago was always 30s, but someone posted a patch
>> to give it a config knob…
> 
> 
> 
> "Proceeding will roll back the file system to a previous state, and may cause the loss of successfully written data since the last commit period (30 seconds by default). Proceed? (Y/N)"

And an important side question is whether "may" is the correct word, or if it should be "will" cause loss of…


Chris Murphy

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Eric Sandeen]

On 8/29/13 3:19 PM, Chris Murphy wrote:
> 
> On Aug 29, 2013, at 1:53 PM, Hugo Mills <hugo@carfax.org.uk> wrote:
> 
>> On Thu, Aug 29, 2013 at 01:44:54PM -0600, Chris Murphy wrote:
>>>
>>> Certainly, if known for sure it won't be more than 30 seconds?
>>
>>   Mmm... it'll depend on the setting of the commit period, which up
>> until a couple of weeks ago was always 30s, but someone posted a patch
>> to give it a config knob…
> 
> 
> 
> "Proceeding will roll back the file system to a previous state, and
> may cause the loss of successfully written data since the last commit
> period (30 seconds by default). Proceed? (Y/N)"

Is it just loss of data, or might this also result in a filesystem with inconsistent metadata, which then requires a fsck?

Above sounds like it's "just" reverting to a previous (consistent) state.  Is that correct?

-Eric

p.s. fwiw when the xfs_repair zero-log option "-L" is used, we say:

"ALERT: The filesystem has valuable metadata changes in a log which is being\n"
"destroyed because the -L option was used.\n"));

Re: Question: How can I recover this partition? (unable to find logical $hugenum len 4096)

[Hugo Mills]

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On Fri, Aug 30, 2013 at 09:44:28AM -0500, Eric Sandeen wrote:
> On 8/29/13 3:19 PM, Chris Murphy wrote:
> > 
> > On Aug 29, 2013, at 1:53 PM, Hugo Mills <hugo@carfax.org.uk> wrote:
> > 
> >> On Thu, Aug 29, 2013 at 01:44:54PM -0600, Chris Murphy wrote:
> >>>
> >>> Certainly, if known for sure it won't be more than 30 seconds?
> >>
> >>   Mmm... it'll depend on the setting of the commit period, which up
> >> until a couple of weeks ago was always 30s, but someone posted a patch
> >> to give it a config knob…
> > 
> > 
> > 
> > "Proceeding will roll back the file system to a previous state, and
> > may cause the loss of successfully written data since the last commit
> > period (30 seconds by default). Proceed? (Y/N)"
> 
> Is it just loss of data, or might this also result in a filesystem with inconsistent metadata, which then requires a fsck?

   No the metadata is always consistent (well, in theory, barring bugs
and out-of-band corruption).

> Above sounds like it's "just" reverting to a previous (consistent) state.  Is that correct?

   Yes, it's dropping the log of accepted-but-uncommitted work. This
is a Bad Thing in the sense that something that's reached the log is
reported to the application as being successfully written. If the
application critically relies on that (e.g. databases), then we've
discarded durability from ACID. (Can you guess I've been marking
Databases resit exam papers this morning? :) )

   Hugo.

> -Eric
> 
> p.s. fwiw when the xfs_repair zero-log option "-L" is used, we say:
> 
> "ALERT: The filesystem has valuable metadata changes in a log which is being\n"
> "destroyed because the -L option was used.\n"));

   That's a reasonable wording too.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
  --- We teach people management skills by examining characters in ---   
            Shakespeare.  You could look at Claudius's crisis            
                   management techniques, for example.                   

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