[LU-19268] Replace qos_exclude_prefixes with qos_exclude_patterns

• Type: Improvement
• Resolution: Fixed
• Priority: Medium
• Fix Version/s: Lustre 2.17.0
• Severity: 3
• Assignee: Sohei Koyama
• Reporter: Sohei Koyama

Description

Problem

With qos_exclude_prefixes, it has been possible to force directories to be created on the same MDT as their parent even when QoS-based MDT distribution is enabled. However, the current functionality only allows exclusions in two cases:

1. When the prefix list contains XXX and name = XXX

1. When the prefix list contains XXX and name = XXX.YYY

This has been sufficient so far, since the main requirement was to exclude only directories like Apache Spark’s _temporary.XXX.

Motivation

Now we also need to support more workloads. In these cases, the directories to be excluded are UUIDs, where a simple prefix match does not provide enough flexibility.

Proposed Change

Introduce qos_exclude_patterns to replace qos_exclude_prefixes.

• qos_exclude_patterns should allow shell-style pattern matching (e.g., "*.[ch]"), providing greater flexibility than prefix-only matching.

• The existing _temporary exclusion, which is currently hard-coded, can be safely changed to _temporary* to preserve the default behavior while leveraging the new pattern-based approach.