[Lustre-discuss] recovering formatted OST

Wojciech Turek wjt27 at cam.ac.uk
Tue Oct 26 09:54:50 PDT 2010


Hi Bernd,

I am not quite clear how creating new OST on a loopback device would help:

Shall I create new OST on a loopback device formatting it with old index and
label and then copy recovered objects to that OST and mount it to the
filesystem?

I think I need to reformat old OST before mounting it as lustre type
filesystem as although fsck recovered some objects (and I can access them
mounting OST as ldiskfs)  if you run tunefs.lustre on that OST device,
tunefs.lustre complaints that it doesn't find any lustre filesystem.

As for the EAs I have created a backup of the recovered objects preserving
EAs.

Best regards,

Wojciech




On 26 October 2010 16:35, Bernd Schubert <bernd.schubert at fastmail.fm> wrote:

> Hello Wojciech,
>
> I think both would work, but why don't just create a small OST with
> mkfs.lustre on a loopback device? And then copy over those files to your
> recovered filesystem.
> Hmm, well, e2fsck might not have fixed all issues and then a reformat
> indeed
> might be helpful.
>
> Also note: EAs on OST objects are a nice to have, but not absolutely
> required.
>
> Cheers,
> Bernd
>
>
> On Tuesday, October 26, 2010, Wojciech Turek wrote:
> > Bernd, I would like to clarify if I understood you suggestion correctly:
> >
> > 1) create a new OST but using old index and old label
> > 2) mount it as ldiskfs and copy recovered objects (using tar or rsync
> with
> > xattrs support) from the old OST to the new OST
> > 3) run --writeconf on MDT and OST of that filesystem
> > 4) mount MDT and all OSTs
> >
> >
> > I guess I could do it also that way:
> >
> > 1) backup restored object using tar or rsync with xattrs support
> > 2) format old OST with old index and old label
> > 3) restore Objects from the backup
> >
> > Do you think that would work?
> >
> > Best regards,
> >
> > Wojciech
> >
> > On 22 October 2010 18:52, Bernd Schubert <bernd.schubert at fastmail.fm>
> wrote:
> > > Hmm, I would probably format a small fake device on a ramdisk and copy
> > > files
> > > over, run tunefs --writeconf /mdt and then start everything (inlcuding
> > > all OSTs) again.
> > >
> > >
> > > Cheers,
> > >
> > > On Friday, October 22, 2010, Wojciech Turek wrote:
> > > > I have tried Bernd's suggestion and it seem to have worked, after
> > > > running e2fsck -D ll_recover_lost_found_objs didn't cause kernel
> panic
> > > > but moved
> > >
> > > a
> > >
> > > > number of objects to O directory. Problem is that I do not have
> > > > last_rcvd file so the OST has no index at the moment. What would be
> > > > the next step
> > >
> > > to
> > >
> > > > enable access to those files in the filesystem?
> > > >
> > > > Best regards,
> > > >
> > > > Wojciech
> > > >
> > > > On 22 October 2010 17:15, Andreas Dilger <andreas.dilger at oracle.com>
> > >
> > > wrote:
> > > > > On 2010-10-22, at 5:42, Bernd Schubert <bernd.schubert at fastmail.fm
> >
> > >
> > > wrote:
> > > > > > Hmm, e2fsck didn't catch that? rec_len is the length of a
> directory
> > > > >
> > > > > entry, so
> > > > >
> > > > > > after how many bytes the next entry follows.
> > > > >
> > > > > I agree that e2fsck should have caught that.
> > > > >
> > > > > > You can try to force e2fsck to do
> > > > > > something about that: e2fsck -D
> > > > >
> > > > > No, I would recommend against using -D at this point. That will
> cause
> > >
> > > it
> > >
> > > > > to re-write the directory contents, and given that the filesystem
> was
> > > > > previously corrupted I would prefer making as few changes as
> possible
> > > > > before the data is estranged.
> > > > >
> > > > > Wojciech,
> > > > > note that if you are able to mount the filesystem you could just
> copy
> > >
> > > all
> > >
> > > > > of the objects (with xattrs!) from lost+found on the bad
> filesystem,
> > > > > along with the last_rcvd file (if you can find it) into a new
> ldiskfs
> > > > > filesystem and then run ll_recover_lost_found_objs on that.
> > > > >
> > > > > > On Friday, October 22, 2010, Wojciech Turek wrote:
> > > > > >> Ok, removing and recreating the journal fixed that problem and I
> > > > > >> am able
> > > > >
> > > > > to
> > > > >
> > > > > >> mount device as ldiskfs filesystem. Now I hit another wall when
> > >
> > > trying
> > >
> > > > > to
> > > > >
> > > > > >> run ll_recover_lost_found_objs
> > > > > >> When I first time run ll_recover_lost_found_objs -d
> > > > > >> /mnt/ost/lost+found
> > > > >
> > > > > it
> > > > >
> > > > > >> only creates the O dir and exits. When I repeat this command
> again
> > > > >
> > > > > kernel
> > > > >
> > > > > >> panics. Any idea what could be the problem here?
> > > > > >>
> > > > > >>
> > > > > >> LDISKFS-fs error (device dm-4): ldiskfs_readdir: bad entry in
> > > > > >> directory #6831: rec_len is smaller than minimal - offset=0,
> > >
> > > inode=0,
> > >
> > > > > >> rec_len=0, name_len=0
> > > > > >> Aborting journal on device dm-4.
> > > > > >> Unable to handle kernel NULL pointer dereference at
> > > > > >> 0000000000000000
> > > > >
> > > > > RIP:
> > > > > >> [<ffffffff88033448>]
> :jbd:journal_commit_transaction+0xc5b/0x12db
> > > > > >> PGD 1a118d067 PUD 1ce7e7067 PMD 0
> > > > > >> Oops: 0002 [1] SMP
> > > > > >> last sysfs file: /class/infiniband_mad/umad0/port
> > > > > >> CPU 3
> > > > > >> Modules linked in: ldiskfs(U) crc16(U) autofs4(U) hidp(U)
> l2cap(U)
> > > > > >> bluetooth(U) rdma_ucm(U) rdma_cm(U) iw_cm(U) ib_addr(U)
> > > > > >> ib_ipoib(U) ipoib_helper(U) ib_cm(U) ipv6(U) xfrm_nalgo(U)
> > > > > >> crypto_api(U)
> > > > >
> > > > > ib_uverbs(U)
> > > > >
> > > > > >> ib_umad(U) mlx4_vnic(U) mlx4_vnic_helper(U) ib_sa(U) ib_mthca(U)
> > > > >
> > > > > mptctl(U)
> > > > >
> > > > > >> dm_mirror(U) video(U) backlight(U) sbs(U) power_meter(U)
> hwmon(U)
> > > > >
> > > > > i2c_ec(U)
> > > > >
> > > > > >> i2c_core(U) dell_wmi(U) wmi(U) button(U) battery(U) asus_acpi(U)
> > > > > >> acpi_memhotplug(U) ac(U) parport_pc(U) lp(U) parport(U)
> sr_mod(U)
> > > > >
> > > > > cdrom(U)
> > > > >
> > > > > >> mlx4_ib(U) ib_mad(U) ib_core(U) joydev(U) mlx4_core(U)
> > >
> > > usb_storage(U)
> > >
> > > > > >> pcspkr(U) shpchp(U) serio_raw(U) i5000_edac(U) edac_mc(U)
> > >
> > > dm_raid45(U)
> > >
> > > > > >> dm_message(U) dm_region_hash(U) dm_log(U) dm_mod(U)
> > > > > >> dm_mem_cache(U)
> > > > >
> > > > > nfs(U)
> > > > >
> > > > > >> lockd(U) fscache(U) nfs_acl(U) sunrpc(U) mptsas(U) mptscsih(U)
> > > > >
> > > > > mptbase(U)
> > > > >
> > > > > >> scsi_transport_sas(U) mppVhba(U) megaraid_sas(U) mppUpper(U)
> sg(U)
> > > > > >> sd_mod(U) scsi_mod(U) bnx2(U) ext3(U) jbd(U) uhci_hcd(U)
> > > > > >> ohci_hcd(U) ehci_hcd(U) Pid: 11360, comm: kjournald Tainted: G
> > > > > >> 2.6.18-194.3.1.el5_lustre.1.8.4 #1
> > > > > >> RIP: 0010:[<ffffffff88033448>]  [<ffffffff88033448>]
> > > > > >>
> > > > > >> :jbd:journal_commit_transaction+0xc5b/0x12db
> > > > > >>
> > > > > >> RSP: 0018:ffff8101c6481d90  EFLAGS: 00010246
> > > > > >> RAX: 0000000000000000 RBX: 0000000000000000 RCX:
> 00000000ffffffff
> > > > > >> RDX: 0000000000000000 RSI: ffff8101e9dab0c0 RDI:
> ffff81022fa46000
> > > > > >> RBP: ffff81022fa46000 R08: ffff81022fa46068 R09:
> 0000000000000000
> > > > > >> R10: ffff810105925b20 R11: 00000000fffffffa R12:
> 0000000000000000
> > > > > >> R13: 0000000000000000 R14: ffff8101e9dab0c0 R15:
> 0000000000000000
> > > > > >> FS:  0000000000000000(0000) GS:ffff810107b9a4c0(0000)
> > > > > >> knlGS:0000000000000000 CS:  0010 DS: 0018 ES: 0018 CR0:
> > > > > >> 000000008005003b CR2: 0000000000000000 CR3: 00000001eaffb000
> CR4:
> > > > > >> 00000000000006e0 Process kjournald (pid: 11360, threadinfo
> > > > > >> ffff8101c6480000, task ffff81021c14c0c0)
> > > > > >> Stack:  ffff8101a61b9000 000000002b8263c0 ffffffff00000000
> > > > >
> > > > > 0000000000000000
> > > > >
> > > > > >> 0000113b00000001 0000000000000013 0000000000000000
> > > > > >> 0000000000000111 0000000000000000 0000000000000000
> > > > > >> 0000000001282dd7 00000000000020dd Call Trace:
> > > > > >> [<ffffffff8003da91>] lock_timer_base+0x1b/0x3c
> > > > > >> [<ffffffff8004b347>] try_to_del_timer_sync+0x7f/0x88
> > > > > >> [<ffffffff88037386>] :jbd:kjournald+0xc1/0x213
> > > > > >> [<ffffffff800a0ab2>] autoremove_wake_function+0x0/0x2e
> > > > > >> [<ffffffff800a089a>] keventd_create_kthread+0x0/0xc4
> > > > > >> [<ffffffff880372c5>] :jbd:kjournald+0x0/0x213
> > > > > >> [<ffffffff800a089a>] keventd_create_kthread+0x0/0xc4
> > > > > >> [<ffffffff80032890>] kthread+0xfe/0x132
> > > > > >> [<ffffffff8005dfb1>] child_rip+0xa/0x11
> > > > > >> [<ffffffff800a089a>] keventd_create_kthread+0x0/0xc4
> > > > > >> [<ffffffff8014bcf4>] deadline_queue_empty+0x0/0x23
> > > > > >> [<ffffffff80032792>] kthread+0x0/0x132
> > > > > >> [<ffffffff8005dfa7>] child_rip+0x0/0x11
> > > > > >>
> > > > > >>
> > > > > >> Code: f0 0f ba 33 01 e8 42 fc 02 f8 8b 03 a8 04 75 07 8b 43 58
> 85
> > > > > >> RIP  [<ffffffff88033448>]
> > > :
> > > :jbd:journal_commit_transaction+0xc5b/0x12db
> > > :
> > > > > >> RSP <ffff8101c6481d90>
> > > > > >> CR2: 0000000000000000
> > > > > >> <0>Kernel panic - not syncing: Fatal exception
> > > > > >>
> > > > > >> On 22 October 2010 03:09, Andreas Dilger
> > > > > >> <andreas.dilger at oracle.com
> > > > >
> > > > > wrote:
> > > > > >>> On 2010-10-21, at 18:44, Wojciech Turek <wjt27 at cam.ac.uk>
> wrote:
> > > > > >>>
> > > > > >>> fsck has finished and does not find any more errors to correct.
> > > > > >>> However when I try to mount the device as ldiskfs kernel panics
> > >
> > > with
> > >
> > > > > >>> following message:
> > > > > >>>
> > > > > >>> Assertion failure in cleanup_journal_tail() at
> > > > > >>> fs/jbd/checkpoint.c:459: "blocknr != 0"
> > > > > >>>
> > > > > >>>
> > > > > >>> Hmm, not sure, maybe your journal is broken?  You can delete it
> > >
> > > with
> > >
> > > > > >>> "tune2fs -O ^has_journal" (maybe after running e2fsck again to
> > >
> > > clear
> > >
> > > > > the
> > > > >
> > > > > >>> journal), then re-create it with "tune2fs -j".
> > > > > >>>
> > > > > >>> ----------- [cut here ] --------- [please bite here ] ---------
> > > > > >>> Kernel BUG at fs/jbd/checkpoint.c:459
> > > > > >>> invalid opcode: 0000 [1] SMP
> > > > > >>> last sysfs file: /class/infiniband_mad/umad0/
> > > > > >>> port
> > > > > >>> CPU 2
> > > > > >>> Modules linked in: obdfilter(U) fsfilt_ldiskfs(U) ost(U) mgc(U)
> > > > > >>> ldiskfs(U) crc16(U) lustre(U) lov(U) mdc(U) lquota(U) osc(U)
> > > > >
> > > > > ksocklnd(U)
> > > > >
> > > > > >>> ko2iblnd(U) ptlrpc(U) obdclass(U) lnet(U) lvfs(U) libcfs(U)
> > > > > >>> autofs4(U) hidp(U) l2cap(U) bluetooth(U) rdma_ucm(U) rdma_cm(U)
> > > > > >>> iw_cm(U)
> > > > >
> > > > > ib_addr(U)
> > > > >
> > > > > >>> ib_ipoib(U) ipoib_helper(U) ib_cm(U) ipv6(U) xfrm_nalgo(U)
> > > > >
> > > > > crypto_api(U)
> > > > >
> > > > > >>> ib_uverbs(U) ib_umad(U) mlx4_vnic(U) mlx4_vnic_helper(U)
> ib_sa(U)
> > > > > >>> ib_mthca(U) mptctl(U) dm_mirror(U) video(U) backlight(U) sbs(U)
> > > > > >>> power_meter(U) hwmon(U) i2c_ec(U) i2c_core(U) dell_wmi(U)
> wmi(U)
> > > > > >>> button(U) battery(U) asus_acpi(U) acpi_memhotplug(U) ac(U)
> > > > >
> > > > > parport_pc(U)
> > > > >
> > > > > >>> lp(U) parport(U) sr_mod(U) cdrom(U) mlx4_ib(U) ib_mad(U)
> > > > > >>> ib_core(U) joydev(U) mlx4_core(U) usb_storage(U) shpchp(U)
> > > > > >>> i5000_edac(U)
> > > > >
> > > > > edac_mc(U)
> > > > >
> > > > > >>> serio_raw(U) pcspkr(U) dm_raid45(U) dm_message(U)
> > > > > >>> dm_region_hash(U) dm_log(U) dm_mod(U) dm_mem_cache(U) nfs(U)
> > > > > >>> lockd(U) fscache(U) nfs_acl(U) sunrpc(U) mptsas(U) mptscsih(U)
> > > > > >>> mptbase(U)
> > > > > >>> scsi_transport_sas(U) mppVhba(U) megaraid_sas(U) mppUpper(U)
> > > > > >>> sg(U) sd_mod(U) scsi_mod(U) bnx2(U) ext3(U) jbd(U) uhci_hcd(U)
> > >
> > > ohci_hcd(U)
> > >
> > > > > >>> ehci_hcd(U) Pid: 13891, comm: mount Tainted: G
> > > > > >>> 2.6.18-194.3.1.el5_lustre.1.8.4 #1 RIP:
> 0010:[<ffffffff88034a95>]
> > > > > >>> [<ffffffff88034a95>]
> > > > > >>>
> > > > > >>> :jbd:cleanup_journal_tail+0x9d/0x118
> > > > > >>>
> > > > > >>> RSP: 0018:ffff81016f00da68  EFLAGS: 00010286
> > > > > >>> RAX: 000000000000005a RBX: ffff81012ca12c00 RCX:
> ffffffff80311da8
> > > > > >>> RDX: ffffffff80311da8 RSI: 0000000000000000 RDI:
> ffffffff80311da0
> > > > > >>> RBP: 0000000000000000 R08: ffffffff80311da8 R09:
> 0000000000000001
> > > > > >>> R10: 0000000000000000 R11: 0000000000000080 R12:
> 0000000000000002
> > > > > >>> R13: ffff81012ca12d4c R14: ffff81012ca12c24 R15:
> ffff81017a8d7400
> > > > > >>> FS:  00002abd7cef1f70(0000) GS:ffff810107b9acc0(0000)
> > > > > >>> knlGS:0000000000000000
> > > > > >>> CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > > > > >>> CR2: 000000000042b000 CR3: 000000012813f000 CR4:
> 00000000000006e0
> > > > > >>> Process mount (pid: 13891, threadinfo ffff81016f00c000, task
> > > > > >>> ffff81022e1b7820)
> > > > > >>> Stack:  0000000000000000 ffff81012ca12c00 ffff81017a8d7400
> > > > > >>> ffffffff88037690
> > > > > >>>
> > > > > >>> ffff81012ca12c00 ffff8102034ff000 ffff81017a8d7400
> > > > > >>> 0000000000000000 ffff8102034ff000 ffffffff88a9be56
> > > > > >>> 0000000001000000 ffff8101bf788000
> > > > > >>>
> > > > > >>> Call Trace:
> > > > > >>> [<ffffffff88037690>] :jbd:journal_flush+0xbe/0x248
> > > > > >>> [<ffffffff88a9be56>]
> > > > > >>>
> > > > > >>> :ldiskfs:ldiskfs_mark_recovery_complete+0x36/0x90
> > > > > >>>
> > > > > >>> [<ffffffff88aa02e0>] :ldiskfs:ldiskfs_fill_super+0x1790/0x1950
> > > > > >>> [<ffffffff800eccd2>] get_filesystem+0x12/0x3b
> > > > > >>> [<ffffffff800e343e>] test_bdev_super+0x0/0xd
> > > > > >>> [<ffffffff88a9eb50>] :ldiskfs:ldiskfs_fill_super+0x0/0x1950
> > > > > >>> [<ffffffff800e43fd>] get_sb_bdev+0x10a/0x16c
> > > > > >>> [<ffffffff800e3d9a>] vfs_kern_mount+0x93/0x11a
> > > > > >>> [<ffffffff800e3e63>] do_kern_mount+0x36/0x4d
> > > > > >>> [<ffffffff800ee601>] do_mount+0x6a9/0x719
> > > > > >>> [<ffffffff800090d2>] __handle_mm_fault+0x96f/0xfaa
> > > > > >>> [<ffffffff8002c9e0>] mntput_no_expire+0x19/0x89
> > > > > >>> [<ffffffff8000a72a>] __link_path_walk+0xf1e/0xf42
> > > > > >>> [<ffffffff800220ce>] __up_read+0x19/0x7f
> > > > > >>> [<ffffffff80066b88>] do_page_fault+0x4fe/0x874
> > > > > >>> [<ffffffff8002c9e0>] mntput_no_expire+0x19/0x89
> > > > > >>> [<ffffffff8000ea45>] link_path_walk+0xa6/0xb2
> > > > > >>> [<ffffffff800cc329>] zone_statistics+0x3e/0x6d
> > > > > >>> [<ffffffff8000f2cf>] __alloc_pages+0x78/0x308
> > > > > >>> [<ffffffff8004c68e>] sys_mount+0x8a/0xcd
> > > > > >>> [<ffffffff8005d28d>] tracesys+0xd5/0xe0
> > > > > >>>
> > > > > >>> Code: 0f 0b 68 3a 94 03 88 c2 cb 01 44 39 a3 58 01 00 00 75 0e
> c7
> > > > > >>> RIP  [<ffffffff88034a95>] :jbd:cleanup_journal_tail+0x9d/0x118
> > > > > >>>
> > > > > >>> RSP <ffff81016f00da68>
> > > > > >>> <0>Kernel panic - not syncing: Fatal exception
> > > > > >>>
> > > > > >>> Any idea how to fix this?
> > > > > >>>
> > > > > >>> Many thanks
> > > > > >>>
> > > > > >>> Wojciech
> > > > > >>>
> > > > > >>>
> > > > > >>> On 21 October 2010 17:54, Wojciech Turek < <wjt27 at cam.ac.uk>
> > > > > >>>
> > > > > >>> wjt27 at cam.ac.uk> wrote:
> > > > > >>>> Thanks Ken, that worked.
> > > > > >>>>
> > > > > >>>>
> > > > > >>>> On 21 October 2010 17:39, Ken Hornstein <
> > > > > >>>> <kenh at cmf.nrl.navy.mil>
> > > > > >>>>
> > > > > >>>> kenh at cmf.nrl.navy.mil> wrote:
> > > > > >>>>>> Now I have another problem. After last segfault I can not
> > >
> > > restart
> > >
> > > > > the
> > > > >
> > > > > >>>>> fsck
> > > > > >>>>>
> > > > > >>>>>> due to MMP.
> > > > > >>>>>> [...]
> > > > > >>>>>> Also when I try to access filesystem via debugfs it fails:
> > > > > >>>>>>
> > > > > >>>>>> debugfs -c -R 'ls' /dev/scratch2_ost16vg/ost16lv
> > > > > >>>>>> debugfs 1.41.10.sun2 (24-Feb-2010)
> > > > > >>>>>> /dev/scratch2_ost16vg/ost16lv: MMP: fsck being run while
> > > > > >>>>>> opening
> > > > > >>>>>
> > > > > >>>>> filesystem
> > > > > >>>>>
> > > > > >>>>>> ls: Filesystem not open
> > > > > >>>>>>
> > > > > >>>>>> Is there a way to clear teh MMP flag so it allows fsck to
> run?
> > > > > >>>>>
> > > > > >>>>> You want tune2fs -f -E clear-mmp
> > > > > >>>>>
> > > > > >>>>> --Ken
>
>


-- 
Wojciech Turek

Senior System Architect

High Performance Computing Service
University of Cambridge
Email: wjt27 at cam.ac.uk
Tel: (+)44 1223 763517
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