Bug 1255827

Summary:	[RH-COMMON] FAILED assert(m_seed < old_pg_num) in librbd when increasing placement groups
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	Jason Dillaman <jdillama>
Component:	RBD	Assignee:	Josh Durgin <jdurgin>
Status:	CLOSED WONTFIX	QA Contact:	ceph-qe-bugs <ceph-qe-bugs>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	1.2.3	CC:	ceph-eng-bugs, jdillama, kdreyer, nlevine, tmuthami, vumrao
Target Milestone:	rc	Keywords:	Reopened
Target Release:	1.2.4
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	1255830 (view as bug list)		Environment:
Last Closed:	2015-12-08 16:27:53 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:	1271774
Bug Blocks:

Description Jason Dillaman 2015-08-21 16:12:04 UTC

Description of problem:
If librbd has an image opened and the image header's placement group is split (via increasing the number of placement groups), librbd will crash due to a failed assertion.

Version-Release number of selected component (if applicable):
ceph-0.80.8-16

How reproducible:
100%

Steps to Reproduce:
1. create a pool 'test' with 8 pgs
2. rbd create --pool test --image-format 1 --size 1024 foo
3. rbd watch --pool test foo
4. ceph osd pool set test pg_num 16

Actual results:
FAILED assert(m_seed < old_pg_num)

Expected results:
librbd transparently handles the PG increase.

Additional info:

Comment 2 Jason Dillaman 2015-08-21 16:23:39 UTC

Technically -- will only fail if the "RBD header's placement hash" module "old PG count mask" != "RBD header's placement hash" modulo "new PG count mask".  Therefore, the larger the increase in PG count (i.e. double the size), the more likely you will encounter the issue.

Comment 3 Ken Dreyer (Red Hat) 2015-09-01 18:15:11 UTC

Jason and Josh, I'm thinking this bug is a duplicate of bug 1258625. Do you agree?

Comment 4 Josh Durgin 2015-09-01 18:27:35 UTC

Yeah, same bug. Close whichever is convenient.

Comment 5 Ken Dreyer (Red Hat) 2015-09-01 18:32:26 UTC

Thanks! closing this one, since 1258625 has more people on the CC and the customer portal cases attached.

*** This bug has been marked as a duplicate of bug 1258625 ***

Comment 6 Ken Dreyer (Red Hat) 2015-09-03 02:36:42 UTC

On second thought, we'll need this BZ in order to track the librbd fix in RH-COMMON.

Comment 7 Ken Dreyer (Red Hat) 2015-12-08 16:27:53 UTC

Closing all RHCS 1.2 bugs, since we are not planning to do a formal RHCS 1.2.4 release.

This particular issue was already fixed in RHCS 1.3, in https://bugzilla.redhat.com/show_bug.cgi?id=1255830