Bug 1840455

Summary: VDO may log spurious errors when entering read-only mode
Product: Red Hat Enterprise Linux 8 Reporter: corwin <corwin>
Component: kmod-kvdoAssignee: corwin <corwin>
Status: CLOSED ERRATA QA Contact: Filip Suba <fsuba>
Severity: low Docs Contact:
Priority: unspecified    
Version: 8.0CC: awalsh, fsuba
Target Milestone: rcFlags: pm-rhel: mirror+
Target Release: 8.0   
Hardware: Unspecified   
OS: Linux   
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Fixed In Version: 6.2.3.91 Doc Type: If docs needed, set a value
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Last Closed: 2020-11-04 02:01:49 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description corwin 2020-05-27 01:10:31 UTC 
Description of problem:

When VDO encounters an unrecoverable error, it enters read-only mode. Any write requests which are in progress once VDO has entered read-only mode should be failed with a VDO_READ_ONLY error. 

However, the VDO kernel module uses a number of threads, and the notification that the device has gone read-only can race with the clean up of failed write requests, causing them log a spurious error of the form:
 "VDO not read-only when cleaning DataVIO with RJ lock"

While there is no actual problem, this could cause confusion for customers and unnecessary support calls.

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


How reproducible:

Difficult

Steps to Reproduce:
1. Initiate writing to a VDO
2. Cause the VDO to enter read-only mode while writes are in progress, for example by introducing an I/O error from the underlying storage.
3. Observe log message of the form described above after the appearance of the log message indicating the IO error.

Actual results:

After an I/O error from the underlying storage, VDO logs errors of the form "VDO not read-only when cleaning DataVIO with RJ lock" 

Expected results:

VDO does not log such errors after an I/O error.

Additional info:
Comment 4 Filip Suba 2020-09-09 08:59:59 UTC 
Verified SanityOnly. Regression testing passed.
Comment 7 errata-xmlrpc 2020-11-04 02:01:49 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (kmod-kvdo bug fix and enhancement update), and where to find the updated
files, follow the link below.

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

https://access.redhat.com/errata/RHBA-2020:4551