[smengcl]

Generated-by: Claude Code (Opus 5.5)

What changes were proposed in this pull request?

When a read or write of container data or metadata hits an I/O error, the datanode only schedules an on-demand volume check. That check writes a small file, syncs it and reads it back, so it lands on new sectors and the read is likely served from page cache. It keeps passing on a disk that fails reads of existing data, and such a disk only shows up as containers being marked UNHEALTHY one at a time, with nothing tying the errors to the same volume.

HDDS-11943 proposed failing the volume after enough of these errors and was closed in favour of the degraded volume design in #8405. Its "IO Error Count" check needs these errors counted per volume first. This PR counts and reports them, without changing the volume state:

• Add DiskCheckUtil#isDiskIOError. It matches EIO, EROFS, ENXIO/ENODEV, EUCLEAN and EREMOTEIO messages, and SyncFailedException, anywhere in the cause chain. Missing files, ENOSPC, EMFILE and permission errors are not counted.
• Add StorageVolumeUtil#onFailure(StorageVolume, Throwable) and pass the exception from the existing data path call sites: ChunkUtils read/write, FilePerBlockStrategy, StreamDataChannelBase, KeyValueContainer, BlockUtils and HddsVolumeUtil.
• Record disk I/O errors found by the container scanners as well.
• Add a NumDataPathIOErrors counter to VolumeInfoMetrics, plus a WARN log naming the volume, logged at most once per hdds.datanode.disk.check.min.gap.

A later change can feed this count into the degraded sliding window from the design.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-17261

How was this patch tested?

New unit tests for the error classification (TestDiskCheckUtil), the per volume count through StorageVolumeUtil#onFailure (TestHddsVolume), and recording from the container data scanner (TestBackgroundContainerDataScanner).

🤖 Generated with Claude Code

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