Bug 2182208

Summary:	Support 64-bit block status and bulk zero over NBD in qemu
Product:	Red Hat Enterprise Linux 9	Reporter:	Eric Blake <eblake>
Component:	qemu-kvm	Assignee:	Eric Blake <eblake>
qemu-kvm sub component:	NBD	QA Contact:	aihua liang <aliang>
Status:	CLOSED MIGRATED	Docs Contact:
Severity:	medium
Priority:	medium	CC:	eblake, jinzhao, juzhang, kwolf, virt-maint, xuwei, zhguo
Version:	9.2	Keywords:	MigratedToJIRA, RFE, Triaged
Target Milestone:	rc	Flags:	pm-rhel: mirror+
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2023-09-22 16:55:47 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:

Description Eric Blake 2023-03-27 22:12:07 UTC

Description of problem:
Upstream NBD is considering an extension to add 64-bit commands. While read and write will still be bounded at qemu's 32M limit for payload size, other commands without large payloads (block status, trim, and write-zero) benefit from being able to request an action over more than just 32 bits of length from a given 64-bit offset.  Supporting 64-bit lengths in the NBD protocol requires opt-in from both client and server, both of which are utilized in qemu.

Version-Release number of selected component (if applicable):


How reproducible:
100%

Steps to Reproduce:
1. Create a 5G image, serve it over qemu-nbd (or qemu-storage-daemon), then use qemu-io to query block status or perform a 'write -z' to the entire image. Watching --trace=nbd_* output can show whether the requests had to be broken up at 32-bit boundaries or done in one go.
2.
3.

Actual results:


Expected results:


Additional info:
See also https://lists.debian.org/nbd/2022/11/msg00008.html

Comment 3 Eric Blake 2023-04-24 20:38:44 UTC

Upstream spec changes have landed; next step is another round of qemu patches implementing that spec: https://github.com/NetworkBlockDevice/nbd/blob/extension-ext-header/doc/proto.md

Comment 4 Eric Blake 2023-04-24 21:10:41 UTC

See also bug 2189341 for libnbd

Comment 5 RHEL Program Management 2023-09-22 16:54:38 UTC

Issue migration from Bugzilla to Jira is in process at this time. This will be the last message in Jira copied from the Bugzilla bug.

Comment 6 RHEL Program Management 2023-09-22 16:55:47 UTC

This BZ has been automatically migrated to the issues.redhat.com Red Hat Issue Tracker. All future work related to this report will be managed there.

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