Use atomic.Pointer for vidMap cache field to prevent data races
during cache trimming in resetVidMap. This addresses the race condition
where concurrent GetLocations calls could read the cache pointer while
resetVidMap is modifying it during cache chain trimming.
Changes:
- Changed cache field from *vidMap to atomic.Pointer[vidMap]
- Updated all cache access to use Load() and Store() atomic operations
- Updated shallowClone, GetLocations, deleteLocation, deleteEcLocation
- Updated resetVidMap to use atomic operations for cache trimming
Added a shallowClone() method to vidMap to improve encapsulation and prevent
MasterClient from directly accessing vidMap's internal fields.
Changes:
1. Added vidMap.shallowClone() in vid_map.go
- Encapsulates the shallow copy logic within vidMap
- Makes vidMap responsible for its own state representation
- Documented that caller is responsible for thread safety
2. Simplified resetVidMap() in masterclient.go
- Uses tail := mc.vidMap.shallowClone() instead of manual field access
- Cleaner, more maintainable code
- Better adherence to encapsulation principles
Benefits:
- Improved code organization and maintainability
- vidMap internals are now properly encapsulated
- Easier to modify vidMap structure in the future
- More self-documenting code
Verified with: go test -race ./weed/wdclient/... (passes)
The vidMap structure is modified to a linked list structure (the length is limited to 5). When the vidMap is reset, the current vidMap is added to the new vidMap as a cache node. When the query locations is empty, the cache node is searched to avoid problems when the master switches leaders.
chrislu
Aleksey Kosov
LHHDZ
Konstantin Lebedev
ningfd
Konstantin Lebedev
divinerapier
j.laycock
Chris Lu