Re: BUG: Files corrupt after moving LVM volume to USB disk

[Lennart Sorensen]

On Tue, Mar 20, 2007 at 12:34:08PM +0200, Marti Raudsepp wrote:
> Second repost of "BUG: Killing and reviving files with USB disks", this time
> also destined to linux-fsdevel.
> 
> This is a reproducible demonstration of the problem initially reported in my
> first e-mail, titled "PROBLEM: 'bio too big device' after moving to a USB
> disk" (http://lkml.org/lkml/2007/3/7/657)
> 
> Summary:
> 01. Create LVM volume; initialize dm-crypt; initialize reiserfs; mount
> 02. Populate the disk with files; sync; flush caches
> 03. Confirm that the files are still readable and non-corrupt (sha1sum)
> 04. Migrate logical volume to USB disk; sync; flush caches
> 05. Confirm that ALL PREVIOUSLY VERIFIED FILES ARE CORRUPT
> 06. Observe "bio too big device dm-0 (256 > 240)" messages in dmesg
> 07. Run reiserfsck to check for corruptions -- none.
> 08. Migrate logical volume back to SATA disk; sync; flush caches
> 09. Confirm that files are readable and non-corrupt again
> 10. Clean up

Not that I really have a clue, but some questions anyhow:

(I noticed someone else complained about lvm/dm-crypt/reiserfs problems
a few months ago here: http://lkml.org/lkml/2007/1/18/146)

Does this happen only with this combination, or can you elliminate
something as the cause? 

Does it happen with ext3 or only reiserfs?

Does it require dm-crypt or is just moving the LVM enough to cause the
problem?

Do you ever unmount and shutdown the lvm during this test?

What happens if you were to build the LVM and filesystem, then issue the
move, and then reboot.  Can you then read them from the USB device or is
it still corrupt?

> Environment/configuration:
> * Linux non 2.6.19-gentoo-r6 #1 Wed Feb 28 20:55:24 EET 2007 x86_64 AMD
>  Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux

Using any insane gentoo compiler options?

> * USB disk 120GB Western Digital, model 00UE-00KVT0 (according to udev),
>  serial DEF10CD7F64C
> * Older SATA disk 200GB Seagate 7200.7, model ST3200822AS
> * Motherboard Asus A8N5X, nForce4 chipset
> * Offending file system: reiserfs v3.6, mounted with noatime,barrier=flush
> * dm-crypt using aes-256 with cbc-essiv:sha256; using assembly-optimized AES
>  on x86_64 (CONFIG_CRYPTO_AES_X86_64)
> * Test partition is 68 extents times 16MiB = 1088 MiB large (that's the
>  largest I could allocate while remaining in one segment -- otherwise lvmove
>  wouldn't move the partition back to /dev/sda5 after "defragmenting" it.)

That sounds strange.

> * LVM utilities version: 2.02.17 (2006-12-14)
> * LVM library version: 1.02.12 (2006-10-13)
> * LVM driver version: 4.10.0
> * cryptsetup-luks 1.0.4 (user space interface to dm-crypt)
> 
> Involved block devices:
> * /dev/sda: My old SATA disk.
> * /dev/sda5: The LVM partition on the old disk.
> * /dev/sdb: The new offending USB disk; whole disk is used as an LVM 
> physical
>            volume.
> * /dev/primary: LVM volume group 'primary', consisting of /dev/sdb and
>                /dev/sda5
> * /dev/primary/punchbag: LVM volume 'punchbag' for demonstration purposes.
> * /dev/mapper/crypt-punchbag: The dm-crypt "decrypted" loopback device.
> 
> 
> ----
> 00. PV information
> 
> [non]# pvdisplay /dev/sda5
>  --- Physical volume ---
>  PV Name               /dev/sda5
>  VG Name               primary
>  PV Size               145.83 GB / not usable 2.73 MB
>  Allocatable           yes
>  PE Size (KByte)       16384
>  Total PE              9333
>  Free PE               117
>  Allocated PE          9216
>  PV UUID               YdrDuL-jw5z-J0SA-EEKU-NOC4-6gGR-T90YCA
> 
> [non]# pvdisplay /dev/sdb
>  --- Physical volume ---
>  PV Name               /dev/sdb
>  VG Name               primary
>  PV Size               111.79 GB / not usable 9.46 MB
>  Allocatable           yes
>  PE Size (KByte)       16384
>  Total PE              7154
>  Free PE               7129
>  Allocated PE          25
>  PV UUID               nE8C5L-lfI1-VNgs-Q7ei-1Zz3-GeGT-UNhH4p
> 
> ----
> 01. Create LVM volume; initialize dm-crypt; initialize reiserfs; mount
> 
> [non]# lvcreate -n punchbag --extents 68 primary /dev/sda5
>  Logical volume "punchbag" created
> [non]# lvs --segments -o +devices
>  LV       VG      Attr   #Str Type   SSize   Devices
>  [...]
>  punchbag primary -wi-a-    1 linear   1.06G /dev/sda5(0)
>  [...]
> [non]# cryptsetup luksFormat /dev/primary/punchbag -c
> aes-cbc-essiv:sha256 -h sha1
>  [...]
> Are you sure? (Type uppercase yes): YES
> Enter LUKS passphrase:
> Verify passphrase:
> Command successful.
> [non]# cryptsetup luksOpen /dev/primary/punchbag crypt-punchbag
> Enter LUKS passphrase:
> key slot 0 unlocked.
> Command successful.
> [non]# mkfs.reiserfs /dev/mapper/crypt-punchbag
>  [...]
> Guessing about desired format.. Kernel 2.6.19-gentoo-r6 is running.
> Format 3.6 with standard journal
> Count of blocks on the device: 343920
> Number of blocks consumed by mkreiserfs formatting process: 8222
> Blocksize: 4096
> Hash function used to sort names: "r5"
> Journal Size 8193 blocks (first block 18)
> Journal Max transaction length 1024
> inode generation number: 0
> UUID: c1857208-5090-49dd-9163-9fb002d96a88
> ATTENTION: YOU SHOULD REBOOT AFTER FDISK!
>        ALL DATA WILL BE LOST ON '/dev/mapper/crypt-punchbag'!
> Continue (y/n):y
> 
> Initializing journal - 0%....20%....40%....60%....80%....100%
> Syncing..ok
>  [...]
> 
> ReiserFS is successfully created on /dev/mapper/crypt-punchbag.
> [non]# mkdir /mnt/punchbag
> [non]# mount /dev/mapper/crypt-punchbag /mnt/punchbag -o 
> noatime,barrier=flush
> 
> ----
> 02. Populate the disk with files; sync; flush caches
> 
> [non]# cp -r ~marti/mp3 /mnt/punchbag
>  [... yes, these are legal mp3s ;)]
> cp: writing `/mnt/punchbag/mp3/...': No space left on device
> ^C
> [non]# sync
> [non]# echo 3 > /proc/sys/vm/drop_caches
> [non]# cd /mnt/punchbag/mp3/mr\ Epic\ -\ Sideways
> 
> ----
> 03. Confirm that the files are still readable and non-corrupt (sha1sum)
> 
> [non]# sha1sum -c *.sha1
> mr Epic - Sideways - 01. Down Low.flac: OK
> mr Epic - Sideways - 02. Blue Days.flac: OK
> mr Epic - Sideways - 03. Sift.flac: OK
> mr Epic - Sideways - 04. Slipping.flac: OK
> mr Epic - Sideways - 05. Ruff and Tumble.flac: OK
> mr Epic - Sideways - 06. In.flac: OK
> mr Epic - Sideways - 07. Out.flac: OK
> 
> ----
> 04. Migrate logical volume to USB disk; sync; flush caches
> 
> [non]# pvmove -n punchbag /dev/sda5 /dev/sdb
>  [...]
>  /dev/sda5: Moved: 100.0%
> [non]# lvs --segments -o +devices
>  LV       VG      Attr   #Str Type   SSize   Devices
>  [...]
>  punchbag primary -wi-ao    1 linear   1.06G /dev/sdb(25)
> [non]# sync
> [non]# echo 3 > /proc/sys/vm/drop_caches
> 
> ----
> 05. Confirm that all previously verified files are corrupt
> 
> [non]# sha1sum -c *.sha1
> sha1sum: mr Epic - Sideways - 01. Down Low.flac: Input/output error
> mr Epic - Sideways - 01. Down Low.flac: FAILED open or read
> sha1sum: mr Epic - Sideways - 02. Blue Days.flac: Input/output error
> mr Epic - Sideways - 02. Blue Days.flac: FAILED open or read
> sha1sum: mr Epic - Sideways - 03. Sift.flac: Input/output error
> mr Epic - Sideways - 03. Sift.flac: FAILED open or read
> sha1sum: mr Epic - Sideways - 04. Slipping.flac: Input/output error
> mr Epic - Sideways - 04. Slipping.flac: FAILED open or read
> sha1sum: mr Epic - Sideways - 05. Ruff and Tumble.flac: Input/output error
> mr Epic - Sideways - 05. Ruff and Tumble.flac: FAILED open or read
> sha1sum: mr Epic - Sideways - 06. In.flac: Input/output error
> mr Epic - Sideways - 06. In.flac: FAILED open or read
> sha1sum: mr Epic - Sideways - 07. Out.flac: Input/output error
> mr Epic - Sideways - 07. Out.flac: FAILED open or read
> sha1sum: WARNING: 7 of 7 listed files could not be read
> 
> ----
> 06. Observe "bio too big device dm-0 (256 > 240)" messages in dmesg
> 
> [non]# dmesg |tail -n7
> [101403.106825] bio too big device dm-0 (256 > 240)
> [101403.115228] bio too big device dm-0 (256 > 240)
> [101403.115912] bio too big device dm-0 (256 > 240)
> [101403.130529] bio too big device dm-0 (256 > 240)
> [101403.131220] bio too big device dm-0 (256 > 240)
> [101403.141577] bio too big device dm-0 (256 > 240)
> [101403.142255] bio too big device dm-0 (256 > 240)
> 
> ----
> 07. Run reiserfsck to check for corruptions -- none.
> 
> [non]# cd
> [non]# umount /mnt/punchbag
> [non]# reiserfsck --check /dev/mapper/crypt-punchbag
>  [...]
> Will read-only check consistency of the filesystem on
> /dev/mapper/crypt-punchbag
> Will put log info to 'stdout'
> 
> Do you want to run this program?[N/Yes] (note need to type Yes if you 
> do):Yes
> ###########
> reiserfsck --check started at Sat Mar 10 19:00:08 2007
> ###########
> Replaying journal..
> Reiserfs journal '/dev/mapper/crypt-punchbag' in blocks [18..8211]: 0
> transactions replayed
> Checking Internal tree...
> 0%....20%....40%....60%....80%....100%
> Checking Semantic tree...
> There are on the filesystem:
>        Leaves 282
>        Internal nodes 3
>        Directories 18
>        Other files 196
>        Data block pointers 268374 (0 of them are zero)
>        Safe links 0
> No corruptions found
> ###########
> reiserfsck finished at Sat Mar 10 19:00:10 2007
> ###########
> 
> ----
> 08. Migrate logical volume back to SATA disk; sync; flush caches
> 
> [non]# mount /dev/mapper/crypt-punchbag /mnt/punchbag -o 
> noatime,barrier=flush
> [non]# cd /mnt/punchbag/mp3/mr\ Epic\ -\ Sideways
> [non]# pvmove -n punchbag /dev/sdb /dev/sda5
>  [...]
>  /dev/sdb: Moved: 100.0%
> [non]# lvs --segments -o +devices
>  LV       VG      Attr   #Str Type   SSize   Devices
>  [...]
>  punchbag primary -wi-a-    1 linear   1.06G /dev/sda5(0)
>  [...]
> [non]# sync
> [non]# echo 3 > /proc/sys/vm/drop_caches
> 
> ----
> 09. Confirm that files are readable and non-corrupt again
> 
> [non]# sha1sum -c *.sha1
> mr Epic - Sideways - 01. Down Low.flac: OK
> mr Epic - Sideways - 02. Blue Days.flac: OK
> mr Epic - Sideways - 03. Sift.flac: OK
> mr Epic - Sideways - 04. Slipping.flac: OK
> mr Epic - Sideways - 05. Ruff and Tumble.flac: OK
> mr Epic - Sideways - 06. In.flac: OK
> mr Epic - Sideways - 07. Out.flac: OK
> 
> ----
> 10. Clean up
> 
> [non]# cd
> [non]# umount /mnt/punchbag
> [non]# cryptsetup remove crypt-punchbag
> [non]# lvremove primary/punchbag
> Do you really want to remove active logical volume "punchbag"? [y/n]: y
>  Logical volume "punchbag" successfully removed
> 
> I repeated this five times and each time was able to reproduce the problem.
> More details on the symptoms of the problem in my previous problem report:
> http://lkml.org/lkml/2007/3/7/657
> 
> I'm not subscribed to the list, so please keep me in Cc:.

--
Len Sorensen
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