Bug 1379472

Summary:	Cache target is not always able to transition to error state
Product:	[Community] LVM and device-mapper	Reporter:	Zdenek Kabelac <zkabelac>
Component:	device-mapper	Assignee:	LVM Team <lvm-team>
Status:	ASSIGNED ---	QA Contact:	cluster-qe <cluster-qe>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	2.02.165	CC:	agk, heinzm, jbrassow, prajnoha, zkabelac
Target Milestone:	---	Flags:	rule-engine: lvm-technical-solution?
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:
Bug Blocks:	1377850

Description Zdenek Kabelac 2016-09-26 21:30:37 UTC

Description of problem:

When 'running' cache over scsi device which is 'offlined' it may not always properly transition to Error/Fail state.

To trigger this state:

Create a cached device (i.e. via lvm2:)

modprobe scsi_debug dev_size_mb=100
vgcreate vg /dev/sdXXX
lvcreate -L10 vg
lvcreate -H -L10 vg/lvol0

Offline scsi:

echo offline >/sys/block/sdXXX/device/state

dmsetup status --noflush
vg-lvol0: 0 24576 cache 8 7/2048 128 0/192 0 30 0 0 0 0 0 1 writethrough 2 migration_threshold 2048 smq 0 rw - 

Try to read 1 byte:

dd if=/dev/vg/lvol0  of=/dev/null bs=1 count=1

kernel loops on: rejecting I/O to offline device

If the 'dmsetup status' is with flush -  cache targets switches to Fail state.


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

How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info: