CentOS based linux VM running on Hyper-v : Checking root filesystem fails when kernel switches having old PV(para virtualised driver based on 2.6.32 linux kernel) to new PV(which is equivalent to linux integration component 3.4)

Question

hi all,
I am running a CentOS base VM on top of Hyper-V server. I upgraded PV drivers of Hyper-V in linux kernel 2.6.32 in order to support
Windows Server 2012, then i am hitting below issue on Windows Server 2008 when kernel switches from old PV(which is 2.6.32 based) to new PV(which is equivalent to linux integration component 3.4).i
am hitting following filesystem check error messages :
Setting hostname hostname:
Checking root filesystem
fsck.ext3/dev/hda2:
The superblock could not be read or does not describe correct ext2 filesystem. If the device is valid and it really contains an ext2
filesystem(and not swap or ufs or something else),then the superblock is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
: No such file or directory while trying to open /dev/hda2
*** An error occurred during the filesystem check.
*** Dropping you to a shell; the system will reboot
*** When you leave the shell.
Also, when I go to the repair filesystem mode. I found out the strange behaviour when i ran those command :
(Repair filesytem) 1 # mount
/dev/hda2 on / type ext3 (rw)
proc on /proc type proc (rw)
(Repair filesystem) 1# cat /etc/mtab
/dev/hda2 /ext3 rw 0 0
proc /proc proc rw 0 0
(Repair filesystem) 1# df
Filesystem 1K-blocks used Available Use% Mountedon
/dev/hda2 4%
I think for all above command there should be /dev/sda2 instead of /dev/hda2.
Also my fstab , and fdisk -l looks like ok for me.
(Repair filesystem) 1# cat /etc/fstab
LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
devpts /dev/pts devpts gid=5,mode=620 0 0
tmpfs /dev/shm tmpfs defaults 0 0
proc /proc proc defaults 0 0
sysfs /sys sysfs defaults 0 0
LABEL=swap-xvda3 swap swap defults 0 0
(Repair filesystem) 1# fdisk -l
Device Boot Start End Block Id System
/dev/sda1 * 1 49 98535 83 Linux
Partition 1 does not end with cylinder boundary.
/dev/sda2 49 19197 39062500 83 Linux
Partition 2 does not end with cylinder boundary.
/dev/sda3 ......
Partition 3 does not ......
/dev/sda4 ......
Partition 4 does not end ....
(Repair filesystem) 1# e2label /dev/sda1
/boot
(Repair filesystem) 1# e2label /dev/sda2
(Repair fielsystem) 1# ls /dev/sd*
/dev/sda /dev/sda1 /dev/sda2 /dev/sda3 /dev/sda4
(Repair filesyatem) 1# ls /dev/hd*
ls: /dev/hd*: No such file or directory
Kindly suggest any configuration of windows server or kernel configs missing or how to resolve this issues
Many many thanks for your reply.
thanks & Regards,
Ujjwal

Answer 1

i am not able to understand duplicate UUID and from where it is picking /dev/hda* ?
~
VVM:>>
VVM:>> Output of dmesg | grep ata contain substring "Hyper-V" ?
VVM:>>
it doesn't contain "Hyper-V" or ata related message and the output doesn't change with boot parameter reserve=0x1f0, 0x8
~~
~~~~
==
 output of dmesg related "ata" Ubuntu v13.04 mini.iso ( with boot parameter reserve=0x1f0, 0x8)
==
 see later ( in "good situation" example  )
~~
===
Disable legacy ATA driver by adding the following to kernel command line in /boot/grub/menu.lst:
reserve=0x1f0, 0x8
. (This option reserves this I/O region and prevents ata_piix from loading).
==
 See output of dmesg related "ata" Ubuntu v13.04 mini.iso ( with boot parameter reserve=0x1f0, 0x8) :
~~
[ 0.176027] 
libata version 3.00 loaded.
[ 0.713319] 
ata_piix 0000:00:07.1: version 2.13
[ 0.713397] 
ata_piix 0000:00:07.1: device not available (can't reserve [io 0x0000-0x0007])
[ 0.713404] 
ata_piix: probe of 0000:00:07.1 failed with error -22
[ 0.713474] 
pata_acpi 0000:00:07.1: device not available (can't reserve [io 0x0000-0x0007])
[ 0.713479] 
pata_acpi: probe of 0000:00:07.1 failed with error -22
~~
  As result: 1) IDE disk handled by hv_storvsc , but 2) no CD-ROM device
==
~ # blkid
/dev/sda1: LABEL="ARCH_BOOT" UUID="009c2043-4bl7-4f95-al4d-fb8951f95b5d" TYPE="ext2"
==
~~
VVM>>
VVM>>Q1: Output of blkid contain duplicate UUID ?
VVM>>
-> blkid contains duplicate UUID, below are the output.
~~
 This situation is classic problem "
use hv_storvsc instead of ata_piix to handle the IDE disks devices ( but not for the DVD-ROM / CD-ROM device handling)
~~
 For compare, see example "good situation": 
 See output of dmesg related "ata" Ubuntu v13.04 mini.iso ( without boot parameter reserve=0x1f0, 0x8) :
~~~~
~ # dmesg |grep ata
[ 0.167224] libata version 3.00 loaded.
[ 0.703109] ata_piix 0000:00:07.1: version 2.13
[ 0.703267] ata_piix 0000:00:07.1: Hyper-V Virtual Machine detected, ATA device ignore set
[ 0.703339] ata_piix 0000:00:07.1: setting latency timer to 64
[ 0.704968] scsi0 : ata_piix
[ 0.705713] scsi1 : ata_piix
[ 0.706191] atal: PATA max UDMA/33 cmd 0xlf0 ctl 0x3f6 bmdma 0xffa0 irq 14
[ 0.706194] ata2: PATA max UDMA/33 cmd 0x170 ctl 0x376 bmdma 0xffa8 irq 15
[ 0.868844] atal.00: host indicates ignore ATA devices, ignored
[ 0.869142] ata2.00: ATAPI: Virtual CD, , max MWDMA2
[ 0.871736] ata2.00: configured for MWDMA2
~~~~
===
~ # uname -a
Linux ubuntu 3.7.0-7-generic #15-Ubuntu SUP Sat Dec 15 14:13:08 UTC 2012 x86_64 GNU/Linux
~ # lsmod
hv_netvsc 22769 0
hv_storvsc 17496 3
hv_utils 13569 0
hv_vmbus 34432 3 hv_netvsc,hv_storvsc,hv_utils
~ # blkid
/dev/sr0: LABEL=”CDROM" TYPE="iso9660”
/dev/sda1: LABEL="ARCH_BOOT" UUID="009c2043-4bl7-4f95-al4d-fb8951f95b5d" TYPE="ext2"
===
 ( only CD-ROM and 1( one) IDE disk connected to ATA)
~~
regarding ata_piix.c patch . . .
As far as i understand this patch , it ignore ATA devices on Hyper-V when PV drivers(CONFIG_HYPERV_STORAGE=y) are enabled.
~~
 Yes:
ignore ATA-HDD ( but not ignore ATA CD-ROM )  on Hyper-V when PV drivers(CONFIG_HYPERV_STORAGE=y) are enabled.
~
 this patches need be backported:
  cd006086fa5d ata_piix: defer disks to the Hyper-V drivers by default
and its prerequisite
  db63a4c8115a libata: add a host flag to ignore detected ATA devices
~
~~
P.S.
 Are You do this:
==
As temporary solution, increase on 1-2 Gb size all .vhd connected to IDE bus
( but not increase size of partitions inside disks)
==
? fsck write message a-la: "no error in file system" ?
2013-01-24 Answer by Ujjwal Kumar: As a temporary solution looks ok for me, but [ VVM: need true solution ]
P.P.S.
To Ujjwal Kumar :
 My e-mail:
ZZZZZZZZZZZZZZZ
please send e-mail to me,  in reply I send to You patches to ata_piix ( and *.c before and after patches) , etc.
} on 2013-01-14 -- DoNe