[kernel BUG at btrfs/tree-log.c:820!] Ubuntu cannot mount my btrfs /home partition

Screenshot of booting my Ubuntu 11.04 64bit

Screenshot of booting of Kubuntu 11.04 Live-CD

From the logs - looks like btrfs isn't happy; there are also some media errors - but those look like they are from the live cd you're using

[ 29.774376] kernel BUG at /build/buildd/linux-2.6.38/fs/btrfs/tree-log.c:820!
[ 29.774392] invalid opcode: 0000 [#1] SMP
[ 29.774405] last sysfs file: /sys/devices/virtual/bdi/btrfs-1/uevent
[ 29.774418] CPU 6
[ 29.774424] Modules linked in: dm_raid45 xor btrfs zlib_deflate libcrc32c nouveau ttm drm_kms_helper drm usb_storage usbhid hid uas i2c_algo_bit ahci tg3 libahci video
[ 29.774449]
[ 29.774451] Pid: 391, comm: exe Not tainted 2.6.38-8-generic #42-Ubuntu LENOVO 20035 /Base Board Product Name
[ 29.774463] RIP: 0010:[<ffffffffa0209645>] [<ffffffffa0209645>] add_inode_ref+0x465/0x480 [btrfs]
[ 29.774480] RSP: 0018:ffff88013506d898 EFLAGS: 00010246
[ 29.774484] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 00000000ffff9659
[ 29.774489] RDX: ffffffff81a2b680 RSI: ffffffffa01d6390 RDI: 0000000000000286
[ 29.774495] RBP: ffff88013506d958 R08: ffff8800bf59b9b0 R09: 01315b51400c0000
[ 29.774500] R10: feb0a4fb16c85003 R11: 0000000000000000 R12: 0000000000000097
[ 29.774505] R13: ffff88013506db18 R14: ffff8801314a2550 R15: 000000000000000c
[ 29.774510] FS: 00007f915feb0720(0000) GS:ffff8800bf580000(0000) knlGS:0000000000000000
[ 29.774516] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 29.774520] CR2: 00007f384954aff1 CR3: 0000000136136000 CR4: 00000000000006e0
[ 29.774525] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 29.774530] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 29.774535] Process exe (pid: 391, threadinfo ffff88013506c000, task ffff880136608000)
[ 29.774540] Stack:
[ 29.774543] ffff880131438030 0000000000020000 0000000000000000 0000000200000000
[ 29.774550] 0000000000000000 ffff8801314a2550 0000000000000000 0000000000000000
[ 29.774558] ffff8801314a4000 ffff8801314a2550 ffff88013506d938 ffff8801315b4d00
[ 29.774565] Call Trace:
[ 29.774575] [<ffffffffa01f9812>] ? read_extent_buffer+0xe2/0x1e0 [btrfs]
[ 29.774585] [<ffffffffa020b60e>] replay_one_buffer+0x27e/0x330 [btrfs]
[ 29.774596] [<ffffffffa01f88ba>] ? alloc_extent_buffer+0x7a/0x420 [btrfs]
[ 29.774606] [<ffffffffa020a139>] walk_down_log_tree+0x339/0x480 [btrfs]
[ 29.774616] [<ffffffffa020a375>] walk_log_tree+0xf5/0x230 [btrfs]
[ 29.774626] [<ffffffffa020d1c1>] btrfs_recover_log_trees+0x221/0x310 [btrfs]
[ 29.774636] [<ffffffffa020b390>] ? replay_one_buffer+0x0/0x330 [btrfs]
[ 29.774646] [<ffffffffa01cf353>] ? btree_read_extent_buffer_pages.clone.63+0x73/0xb0 [btrfs]
[ 29.774657] [<ffffffffa01d2f8e>] open_ctree+0x125e/0x15c0 [btrfs]
[ 29.774665] [<ffffffff812e5404>] ? snprintf+0x34/0x40
[ 29.774671] [<ffffffffa01b1e18>] btrfs_fill_super.clone.9+0x78/0x130 [btrfs]
[ 29.774679] [<ffffffff811cc2f4>] ? disk_name+0x64/0xc0
[ 29.774684] [<ffffffff812e1fe7>] ? strlcpy+0x47/0x60
[ 29.774691] [<ffffffffa01b2223>] btrfs_mount+0x353/0x400 [btrfs]
[ 29.774697] [<ffffffff8112b5a0>] ? __alloc_percpu+0x10/0x20
[ 29.774703] [<fffffff...

Yes, they are from Live-CD - I couldn't boot into my Ubuntu so I reported it from Live CD.
BUT after that, I found how to report it from the recovery mode, so bug #804309 is has been reported using my Ubuntu (and not from the Live-CD).

Given that it's the same filesystem on the same machine that's failing to mount I've marked this as dupe; the backtrace ends similarly but is not identical in the previous bits of it:

[ 319.061293] kernel BUG at /home/kernel-ppa/COD/linux/fs/btrfs/tree-log.c:820!
[ 319.061329] invalid opcode: 0000 [#1] SMP
[ 319.061365] last sysfs file: /sys/devices/virtual/bdi/btrfs-1/uevent
[ 319.061398] CPU 0
[ 319.061411] Modules linked in: dm_crypt snd_hda_codec_hdmi ipt_REJECT ipt_LOG xt_multiport xt_limit xt_tcpudp ipt_addrtype snd_hda_codec_realtek xt_state snd_hda_intel snd_hda_codec snd_hwdep arc4 snd_pcm ip6table_filter snd_seq_midi ip6_tables snd_rawmidi uvcvideo nf_nat_irc snd_seq_midi_event videodev iwlagn snd_seq nf_conntrack_irc snd_timer nf_nat_ftp nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 snd_seq_device nf_conntrack_ftp btusb nf_conntrack v4l2_compat_ioctl32 snd iwlcore bluetooth soundcore mac80211 iptable_filter i7core_edac ip_tables x_tables cfg80211 snd_page_alloc edac_core ir_lirc_codec lirc_dev ideapad_laptop sparse_keymap rc_rc6_mce ir_sony_decoder ir_jvc_decoder ir_rc6_decoder ir_rc5_decoder ir_nec_decoder ene_ir rc_core lp parport btrfs zlib_deflate libcrc32c uvesafb usb_storage uas tg3 ahci libahci video
[ 319.062108]
[ 319.062120] Pid: 1144, comm: mount Not tainted 2.6.38-02063808-generic #201106040910 LENOVO 20035 /Base Board Product Name
[ 319.062211] RIP: 0010:[<ffffffffa00d011c>] [<ffffffffa00d011c>] add_inode_ref+0x47c/0x4a0 [btrfs]
[ 319.062271] RSP: 0018:ffff880110eb1858 EFLAGS: 00010246
[ 319.062300] RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffffa00addf5
[ 319.062336] RDX: 0000000100000770 RSI: ffffffffa00a0880 RDI: 0000000000000286
[ 319.062371] RBP: ffff880110eb1908 R08: ffff8800bf417eb0 R09: 0000000000000000
[ 319.062407] R10: 8000000000000000 R11: 0000000000000000 R12: ffff880134a135d8
[ 319.062442] R13: ffff880110eb1aa8 R14: 0000000000000097 R15: 6db6db6db6db6db7
[ 319.062478] FS: 00007f11de0b7800(0000) GS:ffff8800bf400000(0000) knlGS:0000000000000000
[ 319.062518] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 319.062548] CR2: 00007f1a12c02f20 CR3: 0000000133c8b000 CR4: 00000000000006f0
[ 319.062583] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 319.062619] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 319.062654] Process mount (pid: 1144, threadinfo ffff880110eb0000, task ffff880114448000)
[ 319.062694] Stack:
[ 319.062707] 8bb0000100000001 0000000000000000 0000000000000000 0000000234a135d8
[ 319.062762] ffff880134a135d8 ffff880134b00090 ffff880114786800 ffff880114784800
[ 319.062817] ffff880134afd000 ffff88011204d0f8 0000000000000000 000000000002f06d
[ 319.062872] Call Trace:
[ 319.062897] [<ffffffffa00c0a4a>] ? read_extent_buffer+0xda/0x1a0 [btrfs]
[ 319.064383] [<ffffffffa00d2089>] replay_one_buffer+0x279/0x330 [btrfs]
[ 319.065871] [<ffffffffa00d13be>] walk_down_log_tree+0x2be/0x4a0 [btrfs]
[ 319.067355] [<ffffffffa00d1674>] walk_log_tree+0xd4/0x230 [btrfs]
[ 319.068830] [<ffffffff815b46de>] ? mutex_lock+0x1e/0x50
[ 319.070306] [<ffffffffa00d26a5>] btrfs_recover_log_trees+0x205/0x2f0...

Tommy_CZ:

If you can, please also test the latest upstream kernel available. It will allow additional upstream developers to examine this issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results

It's an oops he can reproduce on his fs either off his installation or the live cd producing similar oops.

Same happened here:

My machine suddenly started freezing once in a while spitting out the same kernel bug.
After a few reboots it started happening earlier and earlier, until the machine wasn't even bootable at all.

While from my Precise Beta2 Live-CD, at least the boot partition on my SSD drive was still mountable, it still wasn't possible to mount the btrfs root partition on the same drive.
Trying to mount the partition manually lead to a process infinitely running without any response which could not even be killed by "kill -9 #id".
Trying to auto-mount the partition via Dolphin (KDE) lead to the error message:
"An error occurred while accessing '79,5 GiB Hard Drive', the system responded: An unspecified error has occurred.: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken."

dmesg throws out:
[ 4.864120] device fsid f393d250-0c39-4896-8f8b-5d8c606e5af4 devid 1 transid 5350 /dev/sda5
[ 4.870568] Btrfs detected SSD devices, enabling SSD mode
[ 4.885361] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 4.885369] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 4.885372] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 5.178008] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 5.178016] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 5.178019] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 5.178021] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 5.178023] parent transid verify failed on 54091776 wanted 5351 found 5331
[ 5.178040] ------------[ cut here ]------------
[ 5.178102] kernel BUG at /build/buildd/linux-3.2.0/fs/btrfs/tree-log.c:619!
[ 5.178190] invalid opcode: 0000 [#1] SMP
[ 5.178244] CPU 0
[ 5.178269] Modules linked in: dm_raid45 xor dm_mirror dm_region_hash dm_log btrfs zlib_deflate libcrc32c usb_storage radeon ttm drm_kms_helper usbhid hid pata_atiixp drm i2c_algo_bit wmi r8169
[ 5.178524]
[ 5.178544] Pid: 380, comm: exe Not tainted 3.2.0-20-generic #33-Ubuntu MICRO-STAR INTERNATIONAL CO.,LTD MS-7596/785GM-E65 (MS-7596)
[ 5.178702] RIP: 0010:[<ffffffffa0203302>] [<ffffffffa0203302>] replay_one_extent+0x562/0x570 [btrfs]
[ 5.178834] RSP: 0018:ffff8801185617f8 EFLAGS: 00010282
[ 5.178904] RAX: 00000000fffffffb RBX: ffff880117c5c000 RCX: 0000000000000115
[ 5.178992] RDX: 0000000000000114 RSI: 000060fee0001c20 RDI: ffffea00045dc340
[ 5.179080] RBP: ffff880118561908 R08: ffffffffa01b093a R09: 0000000000000000
[ 5.179172] R10: 0000000000000001 R11: 0000000000000001 R12: 0000000072c69000
[ 5.179260] R13: ffff8801177340a0 R14: ffff880111c0ccd0 R15: ffff880118561966
[ 5.179349] FS: 00007f06c73fe700(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
[ 5.179453] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 5.179524] CR2: 00007fc5494bd000 CR3: 0000000112718000 CR4: 00000000000006f0
[ 5.179612] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ ...

This bug was filed against a series that is no longer supported and so is being marked as Won't Fix. If this issue still exists in a supported series, please file a new bug.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.