Bug 1990180 - UDS index may continue to write data after suspending
Summary: UDS index may continue to write data after suspending
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: kmod-kvdo
Version: 8.5
Hardware: Unspecified
OS: Unspecified
Target Milestone: beta
: ---
Assignee: Matthew Sakai
QA Contact: Filip Suba
Depends On:
TreeView+ depends on / blocked
Reported: 2021-08-04 23:07 UTC by Matthew Sakai
Modified: 2021-11-10 06:40 UTC (History)
3 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Last Closed: 2021-11-09 19:28:45 UTC
Type: Bug
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-92427 0 None None None 2021-08-04 23:10:00 UTC
Red Hat Product Errata RHBA-2021:4359 0 None None None 2021-11-09 19:28:48 UTC

Description Matthew Sakai 2021-08-04 23:07:59 UTC
Description of problem:
When doing a suspend of a VDO volume, one step is to suspend the UDS index. If the suspend does not save the entire index state, then the index may continue to write data even after it claims to be suspended. (This is the sort of suspend that can happen when growing or replacing the underlying device, for example.) This issue was detected by code inspection.

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

How reproducible:

Steps to Reproduce:
This condition is likely hard to reproduce with an ordinary VDO device, but it may be possible to create a VDO volume where the index region (the first 2GB or so) can be made artificially slow by using a dm-delay device behind it. With this kind of setup...

1. Create and start the VDO volume. Wait a while until the index is also online. 
2. Write 3-5GB of data to the VDO volume in order to make some work for the index.
3. Suspend the VDO without saving.

Actual results:
Suspend should complete fairly quickly, but I/O to the index region may continue.

Expected results:
Suspend should not complete until index I/O has completed.

Additional info:

Comment 4 Filip Suba 2021-08-16 12:35:39 UTC
Verified with kmod-kvdo-

Comment 7 errata-xmlrpc 2021-11-09 19:28:45 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.


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