Fix data corruption on CP persistence inconsistency#452
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During BR the IndexSvc journal and the AppendBlkAllocator CP superblock are flushed in parallel with no atomicity guarantee. If the process crashes after the index entry is durable but before the allocator superblock is written, the receiver resumes with the blk_id visible in the index but the allocator watermarks reset. The dedup skip path then bypasses commit_blk entirely, leaving the blocks silently available for reallocation by subsequent blob writes and corrupting the data on disk. The fix re-commits the blk_id recovered from the index entry so the allocator watermarks are restored before new allocations proceed.
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koujl
marked this pull request as ready for review
July 15, 2026 13:04
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https://jirap.corp.ebay.com/browse/SDSTOR-23023
During BR the IndexSvc journal and the AppendBlkAllocator CP superblock are flushed in parallel with no atomicity guarantee. If the process crashes after the index entry is durable but before the allocator superblock is written, the receiver resumes with the blk_id visible in the index but the allocator watermarks reset. The dedup skip path then bypasses commit_blk entirely, leaving the blocks silently available for reallocation by subsequent blob writes and corrupting the data on disk.
The fix re-commits the blk_id recovered from the index entry so the allocator watermarks are restored before new allocations proceed.
Related PR: eBay/HomeStore#896
Also fixes a bug from #435 (https://jirap.corp.ebay.com/browse/SDSTOR-23162)