SaketaChalamchala opened a new pull request, #9869: URL: https://github.com/apache/ozone/pull/9869
## What changes were proposed in this pull request? Currently, 1. **Eviction race:** SnapshotCache cleanup throws an `IllegalStateException` when it finds stale entries in `pendingEvictionQueue` for snapshots that have already been removed from dbMap Ex., say SnapshotPurge invalidates the entry right before the last thread with a reference to the snapshot just closes adding the snapshotID back to the evictionQueue 2. **Inconsistent Bookkeeping**: `invalidate` removes snapshot entry from dbMap but does not remove it from `pendingEvictionQueue` if it exists. 3. **Potential snapshot leak**: Snapshot close failure during cleanup removes the snapshotID from eviction queue and throws an exception. This causes the snapshot to remain in cache even is refCount = 0 and the snapshot entry remains in `dbMap` unless some other thread explicitly invalidates it or references it again. This means `SnapshotCache.lock()` during this time cannot hold the write lock because `lock()` expects the cache to be drained. 4. **Write lock leak**: Fix write lock leak in SnapshotCache. If the cache drain `cleanup(true)` throws an exception write lock is not released in `SnapshotCache.lock()` **Proposed solution:** 1. Handle eviction race appropriately. Log the stale snapshot entry in eviction queue and remove it from the queue. 2. Remove snapshot entry from eviction queu upon successful invalidation. 3. Log snapshot close failure during cleanup but do not remove it from eviction queue so that it's cleanup can be retried later. 4. Catch any unchecked exception during cleanup and release the write lock in `SnapshotCache.lock()` ## What is the link to the Apache JIRA https://issues.apache.org/jira/browse/HDDS-14768 (Please replace this section with the link to the Apache JIRA) ## How was this patch tested? Unit tests to be added. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
