[dm-devel] Announce: unlimited number of shared snapshots
Mikulas Patocka
mpatocka at redhat.com
Tue Dec 2 07:05:28 UTC 2008
Hi
I fixed the ext2 bug (it was unsupported handling of buffer readahead) ---
download the new version of patches from the same location.
I couldn't reproduce the XFS bug. Please retry. Are you sure that you
didn't try to mount the _snapshot_ as XFS? Snapshots are currently not
writeable (they will be writeable in the final version), so attempting to
mount the snapshot read/write would return i/o error to the filesystem and
produce an error message similar to the one displayed.
Thanks for testing it.
Mikulas
> hm... there is no difference.
> so.. i used small lv size. snapshot creation is successful!!
>
> with xfs
> there is snapshot device mount problem.
> [ 2696.337759] Filesystem "dm-3": Disabling barriers, trial barrier write
> failed
> [ 2696.345517] XFS mounting filesystem dm-3
> [ 2696.356009] xfs_force_shutdown(dm-3,0x1) called from line 420 of file
> fs/xfs/xfs_rw.c. Return address = 0xffffffff8037d399
> [ 2696.363710] Filesystem "dm-3": I/O Error Detected. Shutting down
> filesystem: dm-3
> [ 2696.368085] Please umount the filesystem, and rectify the problem(s)
> [ 2696.371756] I/O error in filesystem ("dm-3") meta-data dev dm-3 block
> 0x200022 ("xlog_bwrite") error 5 buf count 2097152
> [ 2696.378402] XFS: failed to locate log tail
> [ 2696.380797] XFS: log mount/recovery failed: error 5
> [ 2696.405586] XFS: log mount failed
>
> with ext2
> mount is ok!!
> In origin io (cp -a /etc /origin-dev/, however kernel oops detected!
> But cp is successful, and then another snapshot create command (dmsetup
> message /dev/mapper/ms 3 create) hang forever.
>
>
> [ 2782.652061] lost page write due to I/O error on dm-3
> [ 2788.134652] ------------[ cut here ]------------
> [ 2788.135559] kernel BUG at drivers/md/dm-multisnap-io.c:267!
> [ 2788.135559] invalid opcode: 0000 [#1] SMP
> [ 2788.135559] last sysfs file: /sys/block/sde/dev
> [ 2788.135559] CPU 0
> [ 2788.135559] Modules linked in: dm_multisnapshot hangcheck_timer e1000
> e1000e megaraid_sas megaraid_mbox megaraid_mm mptsas mptspi mptscsih mptctl
> mptbase dm_mod scsi_transport_sas scsi_transport_spi sd_mod
> [ 2788.135559] Pid: 4299, comm: kmultisnapd Not tainted 2.6.28-rc5-1128 #1
> [ 2788.135559] RIP: 0010:[<ffffffffa00e4178>] [<ffffffffa00e4178>]
> dm_multisnap_process_bios+0x278/0x600 [dm_multisnapshot]
> [ 2788.135559] RSP: 0018:ffff88001fa77c90 EFLAGS: 00010202
> [ 2788.135559] RAX: 0000000000000001 RBX: ffff88001f8be000 RCX:
> ffff88001f8be0b0
> [ 2788.135559] RDX: ffff88001fa52808 RSI: ffff88001fa77ed0 RDI:
> ffffffffa00e7d80
> [ 2788.135559] RBP: 00000000ffffffff R08: ffff88001fa76000 R09:
> 0000000000000001
> [ 2788.135559] R10: 0000000000000000 R11: 0000000000000000 R12:
> ffff88001f8be0a8
> [ 2788.135559] R13: ffff880023cdd900 R14: 0000000000000000 R15:
> ffff88001fa77e30
> [ 2788.135559] FS: 0000000000000000(0000) GS:ffffffff80658800(0000)
> knlGS:0000000000000000
> [ 2788.135559] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 2788.135559] CR2: 00007f973b475550 CR3: 000000001e11a000 CR4:
> 00000000000006a0
> [ 2788.135559] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000
> [ 2788.135559] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
> 0000000000000400
> [ 2788.135559] Process kmultisnapd (pid: 4299, threadinfo ffff88001fa76000,
> task ffff880025175700)
> [ 2788.135559] Stack:
> [ 2788.135559] ffff880023d58838 ffff88001bf6f800 ffff88001fa77ce0
> ffff880023dc54d0
> [ 2788.135559] 0000000000000086 ffff88001bf6f800 ffff88001bf6f800
> 0000000000000000
> [ 2788.135559] 0000000000000000 ffff880023daac00 ffff880023dc54a0
> 0000000000000000
> [ 2788.135559] Call Trace:
> [ 2788.135559] [<ffffffff804eee34>] ? _spin_unlock_irqrestore+0x4/0x10
> [ 2788.135559] [<ffffffff80228a61>] ? update_curr+0x51/0xb0
> [ 2788.135559] [<ffffffff8022eee0>] ? dequeue_task_fair+0xd0/0xf0
> [ 2788.135559] [<ffffffff80243af0>] ? worker_thread+0x0/0xb0
> [ 2788.135559] [<ffffffff8022b2ad>] ? __dequeue_entity+0x3d/0x50
> [ 2788.135559] [<ffffffff8022b2e5>] ? set_next_entity+0x25/0x50
> [ 2788.135559] [<ffffffff804ecf71>] ? thread_return+0x3a/0x5c9
> [ 2788.135559] [<ffffffffa00e4500>] ? dm_multisnap_work+0x0/0xb0
> [dm_multisnapshot]
> [ 2788.135559] [<ffffffffa00e4533>] ? dm_multisnap_work+0x33/0xb0
> [dm_multisnapshot]
> [ 2788.135559] [<ffffffffa00e4500>] ? dm_multisnap_work+0x0/0xb0
> [dm_multisnapshot]
> [ 2788.135559] [<ffffffff8024302e>] ? run_workqueue+0xbe/0x150
> [ 2788.135559] [<ffffffff80243af0>] ? worker_thread+0x0/0xb0
> [ 2788.135559] [<ffffffff80243af0>] ? worker_thread+0x0/0xb0
> [ 2788.135559] [<ffffffff80243b5d>] ? worker_thread+0x6d/0xb0
> [ 2788.135559] [<ffffffff80246d80>] ? autoremove_wake_function+0x0/0x30
> [ 2788.135559] [<ffffffff80243af0>] ? worker_thread+0x0/0xb0
> [ 2788.135559] [<ffffffff80243af0>] ? worker_thread+0x0/0xb0
> [ 2788.135559] [<ffffffff8024696b>] ? kthread+0x4b/0x80
> [ 2788.135559] [<ffffffff8020cff9>] ? child_rip+0xa/0x11
> [ 2788.135559] [<ffffffff80246920>] ? kthread+0x0/0x80
> [ 2788.135559] [<ffffffff8020cfef>] ? child_rip+0x0/0x11
> [ 2788.135559] Code: 8d b3 a8 00 00 00 e8 08 f9 15 e0 e9 55 ff ff ff 0f 1f 00
> 8d 72 01 e9 4a fe ff ff 48 c7 83 d0 00 00 00 00 00 00 00 e9 e3 fd ff ff <0f>
> 0b eb fe 0f 1f 40 00 48 89 df e8 88 be ff ff 85 c0 0f 85 07
> [ 2788.135559] RIP [<ffffffffa00e4178>] dm_multisnap_process_bios+0x278/0x600
> [dm_multisnapshot]
> [ 2788.135559] RSP <ffff88001fa77c90>
> [ 2788.324941] ---[ end trace cca5fac1560b5d2c ]---
>
>
>
>
> best regards.
>
> Mikulas Patocka wrote:
> > Oh, sorry, there was a bug with big devices. I uploaded new patches at the
> > same location, try them. (there's another fix for bug when sector size is
> > smaller than chunk size in these new patches)
> >
> > BTW. for good performance, make sure that the size of your origin partition
> > is aligned to the chunk size --- otherwise, there's a serious inefficiency
> > in the kernel; if you use it over a partition with odd number of sectors,
> > the kernel will split all IOs to 512 bytes and it'll be very slow.
> >
> > Mikulas
> >
> >
> > > Hi Mikulas
> > > Thanks for your job.
> > >
> > > In my vmware ESXi guest OS (linux-2.6.28-rc5), the multisnap was crashed.
> > >
> > > dd if=/dev/zero of=/dev/LD/snap bs=4096 count=1
> > > echo 0 `blockdev --getsize /dev/mapper/LD-ori` multisnapshot
> > > /dev/mapper/LD-ori /dev/mapper/LD-snap 4096|dmsetup create ms
> > >
> > > [ 298.050106] ------------[ cut here ]------------
> > > [ 298.050106] kernel BUG at drivers/md/dm-bufio.c:156!
> > > [ 298.050106] invalid opcode: 0000 [#1] SMP [ 298.050106] last sysfs
> > > file:
> > > /sys/block/sde/dev
> > > [ 298.050106] CPU 0 [ 298.050106] Modules linked in: dm_multisnapshot
> > > hangcheck_timer e1000 e1000e megaraid_sas megaraid_mbox megaraid_mm mptsas
> > > mptspi mptscsih mptctl mptbase dm_mod scsi_transport_sas
> > > scsi_transport_spi
> > > sd_mod
> > > [ 298.050106] Pid: 1759, comm: dmsetup Not tainted 2.6.28-rc5-1128 #1
> > > [ 298.050106] RIP: 0010:[<ffffffffa002dae4>] [<ffffffffa002dae4>]
> > > get_unclaimed_buffer+0xd4/0x130 [dm_mod]
> > > [ 298.050106] RSP: 0018:ffff8800165edb28 EFLAGS: 00010202
> > > [ 298.050106] RAX: 0000000000000004 RBX: ffff880016219f00 RCX:
> > > ffff880016219f10
> > > [ 298.050106] RDX: 0000000000000902 RSI: 0000000000000001 RDI:
> > > ffff880016219f40
> > > [ 298.050106] RBP: ffff88001624e000 R08: ffff88001624e000 R09:
> > > ffff8800173ca000
> > > [ 298.050106] R10: 0000000000000003 R11: 0000000000000000 R12:
> > > 0000000000000001
> > > [ 298.050106] R13: ffff88001624e000 R14: 000000000020c401 R15:
> > > ffff88001624e020
> > > [ 298.050106] FS: 00007fd02c0356f0(0000) GS:ffffffff80658800(0000)
> > > knlGS:0000000000000000
> > > [ 298.050106] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > > [ 298.050106] CR2: 00007f47f4405590 CR3: 00000000160f6000 CR4:
> > > 00000000000006a0
> > > [ 298.050106] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> > > 0000000000000000
> > > [ 298.050106] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
> > > 0000000000000400
> > > [ 298.050106] Process dmsetup (pid: 1759, threadinfo ffff8800165ec000,
> > > task
> > > ffff880025174c20)
> > > [ 298.050106] Stack:
> > > [ 298.050106] 0000000000000000 ffff880016227000 ffff880016219f00
> > > ffffffffa002deab
> > > [ 298.050106] ffff88001624e860 ffff88001624e068 0000000000000286
> > > ffff8800165edc18
> > > [ 298.050106] 0000000000000000 ffff880025174c20 ffffffff8022b950
> > > 0000000000000000
> > > [ 298.050106] Call Trace:
> > > [ 298.050106] [<ffffffffa002deab>] ? dm_bufio_new_read+0x2ab/0x2f0
> > > [dm_mod]
> > > [ 298.050106] [<ffffffff8022b950>] ? default_wake_function+0x0/0x10
> > > [ 298.050106] [<ffffffffa00e0918>] ? multisnap_origin_ctr+0x4f8/0xc90
> > > [dm_multisnapshot]
> > > [ 298.050106] [<ffffffffa002932b>] ? dm_table_add_target+0x18b/0x3c0
> > > [dm_mod]
> > > [ 298.050106] [<ffffffffa002b2ff>] ? table_load+0xaf/0x210 [dm_mod]
> > > [ 298.050106] [<ffffffff8027b28d>] ? __vmalloc_area_node+0xbd/0x130
> > > [ 298.050106] [<ffffffffa002b250>] ? table_load+0x0/0x210 [dm_mod]
> > > [ 298.050106] [<ffffffffa002c0d1>] ? dm_ctl_ioctl+0x251/0x2c0 [dm_mod]
> > > [ 298.050106] [<ffffffff8029784f>] ? vfs_ioctl+0x2f/0xa0
> > > [ 298.050106] [<ffffffff80297c00>] ? do_vfs_ioctl+0x340/0x470
> > > [ 298.050106] [<ffffffff80297d79>] ? sys_ioctl+0x49/0x80
> > > [ 298.050106] [<ffffffff8020c10b>] ? system_call_fastpath+0x16/0x1b
> > > [ 298.050106] Code: 54 a8 02 74 aa 45 85 e4 74 e9 f6 07 02 74 a0 b9 02 00
> > > 00
> > > 00 48 c7 c2 20 d9 02 a0 be 01 00 00 00 e8 42 fe 4b e0 eb 88 0f 0b eb fe
> > > <0f>
> > > 0b eb fe 31 db eb 84 45 85 e4 90 0f 84 60 ff ff ff b9 02 00 [ 298.050106]
> > > RIP
> > > [<ffffffffa002dae4>] get_unclaimed_buffer+0xd4/0x130 [dm_mod]
> > > [ 298.050106] RSP <ffff8800165edb28>
> > > [ 298.218349] ---[ end trace 9642e91f49f4b2b1 ]---
> > > #dmsetup ls
> > > LD-snap (254, 1)
> > > LD-ori (254, 0)
> > > ms (254, 2)
> > > #ls /dev/mapper/
> > > LD-ori LD-snap control #vgdisplay -v Finding all volume groups
> > > Finding volume group "LD"
> > > --- Volume group ---
> > > VG Name LD
> > > System ID Format lvm2
> > > Metadata Areas 8
> > > Metadata Sequence No 3
> > > VG Access read/write
> > > VG Status resizable
> > > MAX LV 0
> > > Cur LV 2
> > > Open LV 2
> > > Max PV 0
> > > Cur PV 4
> > > Act PV 4
> > > VG Size 53.98 GB
> > > PE Size 4.00 MB
> > > Total PE 13820
> > > Alloc PE / Size 13312 / 52.00 GB
> > > Free PE / Size 508 / 1.98 GB
> > > VG UUID r0hOuU-L4I0-V3Zy-hK10-TtJe-toBw-9BDpCY
> > > --- Logical volume ---
> > > LV Name /dev/LD/ori
> > > VG Name LD
> > > LV UUID LXOLcd-oPdk-xXoq-ZmK6-B4Qd-z8y6-Vf1WZ8
> > > LV Write Access read/write
> > > LV Status available
> > > # open 1
> > > LV Size 26.00 GB
> > > Current LE 6656
> > > Segments 1
> > > Allocation inherit
> > > Read ahead sectors auto
> > > - currently set to 256
> > > Block device 254:0
> > > --- Logical volume ---
> > > LV Name /dev/LD/snap
> > > VG Name LD
> > > LV UUID MlgpYW-AbNZ-7DMd-BEmc-RNiz-wmsa-vNiq1m
> > > LV Write Access read/write
> > > LV Status available
> > > # open 1
> > > LV Size 26.00 GB
> > > Current LE 6656
> > > Segments 4
> > > Allocation inherit
> > > Read ahead sectors auto
> > > - currently set to 256#vgdisplay -v Finding all volume groups
> > > Finding volume group "LD"
> > > --- Volume group ---
> > > VG Name LD
> > > System ID Format lvm2
> > > Metadata Areas 8
> > > Metadata Sequence No 3
> > > VG Access read/write
> > > VG Status resizable
> > > MAX LV 0
> > > Cur LV 2
> > > Open LV 2
> > > Max PV 0
> > > Cur PV 4
> > > Act PV 4
> > > VG Size 53.98 GB
> > > PE Size 4.00 MB
> > > Total PE 13820
> > > Alloc PE / Size 13312 / 52.00 GB
> > > Free PE / Size 508 / 1.98 GB
> > > VG UUID r0hOuU-L4I0-V3Zy-hK10-TtJe-toBw-9BDpCY
> > > --- Logical volume ---
> > > LV Name /dev/LD/ori
> > > VG Name LD
> > > LV UUID LXOLcd-oPdk-xXoq-ZmK6-B4Qd-z8y6-Vf1WZ8
> > > LV Write Access read/write
> > > LV Status available
> > > # open 1
> > > LV Size 26.00 GB
> > > Current LE 6656
> > > Segments 1
> > > Allocation inherit
> > > Read ahead sectors auto
> > > - currently set to 256
> > > Block device 254:0
> > > --- Logical volume ---
> > > LV Name /dev/LD/snap
> > > VG Name LD
> > > LV UUID MlgpYW-AbNZ-7DMd-BEmc-RNiz-wmsa-vNiq1m
> > > LV Write Access read/write
> > > LV Status available
> > > # open 1
> > > LV Size 26.00 GB
> > > Current LE 6656
> > > Segments 4
> > > Allocation inherit
> > > Read ahead sectors auto
> > > - currently set to 256
> > > Block device 254:1
> > > --- Physical volumes ---
> > > PV Name /dev/sda PV UUID
> > > lc8iKg-WrqG-XWyL-t6TW-TtPj-HQn1-pgbtku
> > > PV Status allocatable
> > > Total PE / Free PE 7679 / 508
> > > PV Name /dev/sdc PV UUID
> > > bbHAWq-adBj-ACcU-5Bp6-LM2Y-r5M6-9ncvGc
> > > PV Status allocatable
> > > Total PE / Free PE 2047 / 0
> > > PV Name /dev/sdd PV UUID
> > > 5B7gOQ-KKuk-XtHm-6FSr-11Q4-2p7y-lr2xGP
> > > PV Status allocatable
> > > Total PE / Free PE 2047 / 0
> > > PV Name /dev/sde PV UUID
> > > kXUvPh-gsVN-oQln-CiMu-XdR2-C1Xd-DgLtjb
> > > PV Status allocatable
> > > Total PE / Free PE 2047 / 0
> > >
> > > Block device 254:1
> > > --- Physical volumes ---
> > > PV Name /dev/sda PV UUID
> > > lc8iKg-WrqG-XWyL-t6TW-TtPj-HQn1-pgbtku
> > > PV Status allocatable
> > > Total PE / Free PE 7679 / 508
> > > PV Name /dev/sdc PV UUID
> > > bbHAWq-adBj-ACcU-5Bp6-LM2Y-r5M6-9ncvGc
> > > PV Status allocatable
> > > Total PE / Free PE 2047 / 0
> > > PV Name /dev/sdd PV UUID
> > > 5B7gOQ-KKuk-XtHm-6FSr-11Q4-2p7y-lr2xGP
> > > PV Status allocatable
> > > Total PE / Free PE 2047 / 0
> > > PV Name /dev/sde PV UUID
> > > kXUvPh-gsVN-oQln-CiMu-XdR2-C1Xd-DgLtjb
> > > PV Status allocatable
> > > Total PE / Free PE 2047 / 0
> > >
> > > What's wrong with my test?
> > >
> > > best regards
> > >
> > >
> >
> >
> >
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