Bug 1072339

Summary: RHEV: Cannot start VMs that have more than 23 snapshots.
Product: Red Hat Enterprise Linux 7 Reporter: Jeff Cody <jcody>
Component: qemu-kvmAssignee: Jeff Cody <jcody>
Status: CLOSED CURRENTRELEASE QA Contact: Virtualization Bugs <virt-bugs>
Severity: urgent Docs Contact:
Priority: urgent    
Version: 7.0CC: acathrow, areis, bazulay, bsarathy, chayang, famz, fsimonce, gwatson, hhuang, iheim, jcody, jkurik, juzhang, knoel, kwolf, lbopf, lpeer, michen, mkalinin, mkenneth, pbonzini, qzhang, sgordon, shu, svenkatr, tlavigne, virt-maint, yeylon
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: qemu-kvm-1.5.3-51.el7 Doc Type: Bug Fix
Doc Text:
Previously, the number of characters in the file name strings for virtual machine (VM) images was limited. Because repeated creation of VM image snapshots gradually increases the file name string size, this eventually resulted in either of the following problems when the size limit was reached: creating an image snapshot failed to be executed, or the VM did not successfully boot. This update fixes the handling of file names so that long file names are now supported, and the mentioned problems no longer occur.
Story Points: ---
Clone Of: 1067576
: 1117170 (view as bug list) Environment:
Last Closed: 2014-06-13 10:03:19 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1067576, 1113583    
Bug Blocks: 1023565, 1071023, 1071740, 1072302, 1080820    
Attachments:
Description Flags
Script to reproduce relative pathname bug with just qemu-kvm and qemu-img none

Comment 3 Jeff Cody 2014-03-04 19:32:46 UTC
Created attachment 870610 [details]
Script to reproduce relative pathname bug with just qemu-kvm and qemu-img

Attached is a script to reproduce this bug with just qemu-kvm, and qemu-img.

This can be seen via either live snapshots, or image creation with qemu-img.

This script will do the following:

1) create test directory
2) create a qcow2 base image
3) launch qemu-kvm with qmp over localhost tcp
4) attempt to create 80 live snapshots with a relative pathname, to parent directory and then back into the test directory
5) run qemu-img, create a different set of 80 snapshots off the same base image.
6) kill the process started in step #3

All you should need to edit in the script is the executable path for qemu and qemu-img.

The test directory is left after the script runs, with the created snapshots and an output log, for later examination.

Expected outcome:
Post fix:  All snapshot created successfully (live and via qemu-img)
Prior to fix:  First ~24 snapshots succeed, those after that fail


If you edit the script to create 150 snapshots instead of 80, you will see the fix fail as well.

Comment 5 Miroslav Rezanina 2014-03-05 10:33:20 UTC
Fix included in qemu-kvm-1.5.3-51.el7

Comment 8 Shaolong Hu 2014-03-21 05:22:16 UTC
Verified on qemu-kvm-rhev-1.5.3-55.el7.x86_64:

Run script in comment 3, all 80 snapshots created successfully with both live snapshot and qemu-img.

Comment 10 Ludek Smid 2014-06-13 10:03:19 UTC
This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.