Bug 1690020 - Incorrect I/O when reading and writing OVF disks
Summary: Incorrect I/O when reading and writing OVF disks
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: vdsm
Classification: oVirt
Component: Core
Version: 4.30.8
Hardware: Unspecified
OS: Unspecified
unspecified
urgent
Target Milestone: ovirt-4.3.5
: 4.30.20
Assignee: Nir Soffer
QA Contact: Yosi Ben Shimon
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2019-03-18 15:19 UTC by Nir Soffer
Modified: 2019-07-30 14:08 UTC (History)
3 users (show)

Fixed In Version: vdsm-4.30.20
Clone Of:
Environment:
Last Closed: 2019-07-30 14:08:32 UTC
oVirt Team: Storage
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
oVirt gerrit 100751 0 ovirt-4.3 MERGED imageSharing: OVF I/O correctness 2020-02-05 11:56:54 UTC

Description Nir Soffer 2019-03-18 15:19:52 UTC
Description of problem:

When writing OVF disk to shared storage, vdsm uses:

   dd of=/path/to/image bs=1M

Since we don't use conv=fsync, the data is written to the host page cache.
If a host crash after we wrote OVF or storage become inaccessible, we may 
loose the OVF content, or have partly written (corrupted) OVF.

When reading OVF from dism, vdsm uses:

    dd if=/path/to/disk bs1M count=1

This read the data from the page cache. If the OVF was modified on another
host, we may get stale data form the host page cache.


Version-Release number of selected component (if applicable):
Since OVF was added in 3.5.

How reproducible:
Probably very hard to reproduce.

Comment 1 Yosi Ben Shimon 2019-07-02 12:07:27 UTC
Can I have steps/scenario for testing this, please?

Comment 2 Nir Soffer 2019-07-02 15:22:57 UTC
There is not way to reproduce in the system level, testing means checking
that flows using OVF storage still work (e.g. detach, domain, attach domain,
import vms).

Comment 3 Avihai 2019-07-03 07:11:56 UTC
As written in comment#2 verification of this issue is  checking
that flows using OVF storage still work (e.g. detach, domain, attach domain,
import vms).

All of these flows are tested in automation regression Tier1/2/3 which passed on ovirt-engine 4.3.5-1/vdsm-4.30.20-1.el7ev.x86_64.

Comment 4 Sandro Bonazzola 2019-07-30 14:08:32 UTC
This bugzilla is included in oVirt 4.3.5 release, published on July 30th 2019.

Since the problem described in this bug report should be
resolved in oVirt 4.3.5 release, it has been closed with a resolution of CURRENT RELEASE.

If the solution does not work for you, please open a new bug report.


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