[Xen-devel] HVM guest disk corruption after shutdown

["Huang2, Wei" <Wei.Huang2@xxxxxxx>]

We recently found a disk corruption issue with SLES11 SP1 guest. Basically the guest disk becomes non-bootable after guest shutdown. This is a SLES specific issue as we didn’t see on other Linux and Windows VMs. Here is the configuration:

============

1.      Xen: xen-4.1-testing, changeset 23096

2.      Dom0: Jeremy’s latest pvops 6d94b75 (June 1)

3.      VM: SLES 11 SP1, installed as physical machine with raw disk format

============

 

Regarding the disk before corruption, “file sles11sp1.img” command read: “/root/guests/sles11-sp1/sles11sp1.img: x86 boot sector; partition 1: ID=0x82, starthead 1, startsector 63, 4208967 sectors; partition 2: ID=0x83, active, starthead 0, startsector 4209030, 16755795 sectors”. After corruption, it became a data file: ““/root/guests/sles11-sp1/sles11sp1.img: data”.

 

I traced back to the blkback commit 28080265 by Konrad. If I disabled this change, the corruption issue will disappear.

 

============

diff --git a/drivers/xen/blkback/blkback.c b/drivers/xen/blkback/blkback.c

index fd88f32..30772ec 100644

--- a/drivers/xen/blkback/blkback.c

+++ b/drivers/xen/blkback/blkback.c

@@ -409,8 +409,7 @@ static void dispatch_rw_block_io(blkif_t *blkif,

                break;

        case BLKIF_OP_WRITE_BARRIER:

                operation = WRITE_BARRIER;

-               /* vbd_translate is alergic to bizzare sectors. */

-               req->sector_number = 0;

                break;

        default:

                operation = 0; /* make gcc happy */

============

 

Thanks,

-Wei

 

 

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