I had a multi-drive raid6 setup and failed and removed 2 drives. I tried to start a scrub and rebalance to recalculate the parity and something happened where I could not write to the filesystem. Any programs that tried to interact with the filesystem would stall forever and bring the server load up to ~40000. Anyways, now I am mounting the entire filesystem in degraded and read-only mode and trying to get my data out, but I keep hitting the same kernel bug: Sep 1 17:37:29 storage01 kernel: [ 7781.048714] cp (3796) used greatest stack depth: 2584 bytes left Sep 1 17:42:26 storage01 kernel: [ 8078.141546] BTRFS info (device sdo1): csum failed ino 723851 extent 148790317056 csum 3580889741 wanted 848104669 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.513407] BTRFS info (device sdo1): csum failed ino 723851 extent 4171022393344 csum 2590340982 wanted 848104669 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.513786] BTRFS info (device sdo1): csum failed ino 723851 extent 148790312960 csum 2615865265 wanted 848104669 mirror 1 Sep 1 17:42:26 storage01 kernel: [ 8078.531244] BTRFS info (device sdo1): csum failed ino 723851 extent 4171022467072 csum 653240077 wanted 1839153580 mirror 2 Sep 1 17:42:26 storage01 kernel: [ 8078.532972] BTRFS info (device sdo1): csum failed ino 723851 extent 4171022467072 csum 3962186301 wanted 848104669 mirror 3 Sep 1 17:42:26 storage01 kernel: [ 8078.556560] BTRFS info (device sdo1): csum failed ino 723901 extent 148790509568 csum 3471705361 wanted 3207739402 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.558995] BTRFS info (device sdo1): csum failed ino 723901 extent 4171026595840 csum 623201911 wanted 3385769702 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.559034] BTRFS info (device sdo1): csum failed ino 723901 extent 4171026640896 csum 3647762664 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.561634] BTRFS info (device sdo1): csum failed ino 723901 extent 4171026640896 csum 2832653656 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.561643] BTRFS info (device sdo1): csum failed ino 723901 extent 4171026640896 csum 3839010108 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.562048] BTRFS info (device sdo1): csum failed ino 723901 extent 148790640640 csum 3233112747 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.562553] BTRFS info (device sdo1): csum failed ino 723901 extent 148790640640 csum 2236110192 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.562565] BTRFS info (device sdo1): csum failed ino 723901 extent 148790603776 csum 1364949859 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.562572] BTRFS info (device sdo1): csum failed ino 723901 extent 148790640640 csum 3213213740 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.562581] ------------[ cut here ]------------ Sep 1 17:42:26 storage01 kernel: [ 8078.562588] kernel BUG at fs/btrfs/extent_io.c:2291! Sep 1 17:42:26 storage01 kernel: [ 8078.562592] invalid opcode: 0000 [#1] SMP Sep 1 17:42:26 storage01 kernel: [ 8078.562599] Modules linked in: nfsd ipv6 it87 hwmon_vid eeepc_wmi asus_wmi rfkill video mxm_wmi edac_core kvm_amd kvm k10temp serio_raw pcspkr joydev sp5100_tco i2c_piix4 radeon cfbfillrect cfbimgblt cfbcopyarea fbcon ttm tpm_infineon bitblit softcursor font tileblit drm_kms_helper drm tpm_tis tpm snd_hda_codec_realtek backlight fb fbdev snd_hda_codec_hdmi snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_timer snd soundcore shpchp wmi acpi_cpufreq processor Sep 1 17:42:26 storage01 kernel: [ 8078.562693] CPU: 1 PID: 3821 Comm: btrfs-endio-3 Not tainted 3.14.17 #1 Sep 1 17:42:26 storage01 kernel: [ 8078.562698] Hardware name: To be filled by O.E.M. To be filled by O.E.M./M5A99X EVO R2.0, BIOS 1503 01/16/2013 Sep 1 17:42:26 storage01 kernel: [ 8078.562704] task: ffff88013ab01160 ti: ffff88008ba68000 task.ti: ffff88008ba68000 Sep 1 17:42:26 storage01 kernel: [ 8078.562709] RIP: 0010:[<ffffffff813021e3>] [<ffffffff813021e3>] end_bio_extent_readpage+0x943/0x950 Sep 1 17:42:26 storage01 kernel: [ 8078.562719] RSP: 0000:ffff88008ba69cd8 EFLAGS: 00010202 Sep 1 17:42:26 storage01 kernel: [ 8078.562723] RAX: 0000000000000003 RBX: ffffea00010370c0 RCX: ffffffffffffffff Sep 1 17:42:26 storage01 kernel: [ 8078.562728] RDX: 000000002a638640 RSI: 0000000000000001 RDI: ffff8800b37376b8 Sep 1 17:42:26 storage01 kernel: [ 8078.562733] RBP: ffff88008ba69d98 R08: 000003c995c00000 R09: 000003cc19c00000 Sep 1 17:42:26 storage01 kernel: [ 8078.562759] R10: ffffea0004eac940 R11: ffffffff812dc061 R12: ffff880052a33d00 Sep 1 17:42:26 storage01 kernel: [ 8078.562784] R13: ffff88012a6385e0 R14: 0000000000289000 R15: 0000000000000000 Sep 1 17:42:26 storage01 kernel: [ 8078.562810] FS: 00007f4796229700(0000) GS:ffff88013fd00000(0000) knlGS:0000000000000000 Sep 1 17:42:26 storage01 kernel: [ 8078.562890] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b Sep 1 17:42:26 storage01 kernel: [ 8078.562915] CR2: 00007f4796234000 CR3: 00000000b2e1a000 CR4: 00000000000007e0 Sep 1 17:42:26 storage01 kernel: [ 8078.562941] Stack: Sep 1 17:42:26 storage01 kernel: [ 8078.562965] ffff88008ba69d78 ffffea0004eac940 ffff88008eb13720 ffff88008eb13788 Sep 1 17:42:26 storage01 kernel: [ 8078.563017] ffff88008ba69da8 ffff88008eb138d8 ffff88012a638500 ffff88008eb13760 Sep 1 17:42:26 storage01 kernel: [ 8078.563069] 000000002a638640 0000000000000000 0000000000289fff 0000000000000000 Sep 1 17:42:26 storage01 kernel: [ 8078.563121] Call Trace: Sep 1 17:42:26 storage01 kernel: [ 8078.563148] [<ffffffff811b4523>] bio_endio+0x53/0x90 Sep 1 17:42:26 storage01 kernel: [ 8078.563175] [<ffffffff8116cf1d>] ? kfree+0xfd/0x140 Sep 1 17:42:26 storage01 kernel: [ 8078.563200] [<ffffffff811b456d>] bio_endio_nodec+0xd/0x10 Sep 1 17:42:26 storage01 kernel: [ 8078.563227] [<ffffffff812dc06c>] end_workqueue_fn+0x3c/0x50 Sep 1 17:42:26 storage01 kernel: [ 8078.563254] [<ffffffff81312257>] worker_loop+0x157/0x560 Sep 1 17:42:26 storage01 kernel: [ 8078.563280] [<ffffffff81312100>] ? btrfs_queue_worker+0x300/0x300 Sep 1 17:42:26 storage01 kernel: [ 8078.563307] [<ffffffff81082ff4>] kthread+0xc4/0xe0 Sep 1 17:42:26 storage01 kernel: [ 8078.563333] [<ffffffff81010000>] ? ftrace_raw_event_xen_mmu_alloc_ptpage+0x130/0x180 Sep 1 17:42:26 storage01 kernel: [ 8078.563972] [<ffffffff81082f30>] ? flush_kthread_worker+0x70/0x70 Sep 1 17:42:26 storage01 kernel: [ 8078.563999] [<ffffffff819021cc>] ret_from_fork+0x7c/0xb0 Sep 1 17:42:26 storage01 kernel: [ 8078.564025] [<ffffffff81082f30>] ? flush_kthread_worker+0x70/0x70 Sep 1 17:42:26 storage01 kernel: [ 8078.564050] Code: 54 24 28 e9 a6 fc ff ff 48 8b bd 68 ff ff ff 4c 89 e6 e8 71 e2 ff ff 48 8b 45 a8 48 83 c0 01 48 89 85 60 ff ff ff e9 4d f8 ff ff <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 Sep 1 17:42:26 storage01 kernel: [ 8078.564251] RIP [<ffffffff813021e3>] end_bio_extent_readpage+0x943/0x950 Sep 1 17:42:26 storage01 kernel: [ 8078.564279] RSP <ffff88008ba69cd8> Sep 1 17:42:26 storage01 kernel: [ 8078.564527] BTRFS info (device sdo1): csum failed ino 723901 extent 4171026640896 csum 28745215 wanted 3641694186 mirror 0 Sep 1 17:42:26 storage01 kernel: [ 8078.564569] ---[ end trace 5591f400f3ecd70a ]--- My kernel version is 3.14.17 and I am currently compiling 3.16.1 to see if things are more stable there. What can I try next to get my data out? -- 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