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Intermittent connection failures for NFSv4 hosted guest images can cause KVM guest issues

Flashes (Alerts)


Abstract

The Linux kernel changed which forces it to not retry I/O after the loss of the NFS lock and certain errors that indicate a stateid has become invalid. Attempting to re-establish state in these conditions without notifying the application that such an error occurred is undesirable as it might cause data corruption. In such an event, any I/O to NFS through the exiting stateid returns an -EIO error back to the process. Upstream commit ef1820f9be27 ("NFSv4: Don't try to recover NFSv4 locks when they are lost") in the Linux kernel introduced this behavior to ensure correctness in an event of a transient network disruption event.

Content

Linux Releases Affected
All distribution kernels that are based on Linux kernel version 3.12 or later
IBM Systems Affected
All Power Systems that have KVM guests that run on a PowerVM logical partition (LPAR) and use NFS-backed storage for KVM guest images.
Symptoms

Input/output (I/O) failures in KVM guest and the following warning messages in the host KVM kernel logs:

check lease failed on nfsv4 server


Workaround

If NFSv4-backed storage is used, then the kernel can be booted with boot arg "nfs.recover_lost_locks=1" that restores pre v3.12 behavior where NFS locks are recovered in case of intermittent disconnections.
 
For more information, see the RedHat knowledge article at: https://access.redhat.com/solutions/1179643
 
Fix Outlook

There is no plan to fix this issue as this is primarily the way how the NFSv4 client interacts with NFS servers to ensure correctness in an event of a transient network disruption event.

I/O device impacted

None.

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Document Information

Modified date:
02 February 2026

UID

ibm17167718

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