tx_check: avoid nested read tx when loading freelist during Check#1189
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VedantMadane wants to merge 1 commit intoetcd-io:mainfrom
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tx_check: avoid nested read tx when loading freelist during Check#1189VedantMadane wants to merge 1 commit intoetcd-io:mainfrom
VedantMadane wants to merge 1 commit intoetcd-io:mainfrom
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[APPROVALNOTIFIER] This PR is NOT APPROVED This pull-request has been approved by: VedantMadane The full list of commands accepted by this bot can be found here. DetailsNeeds approval from an approver in each of these files:Approvers can indicate their approval by writing |
Check already runs on a read transaction (often from View on another goroutine). Rebuilding an unsynced freelist called beginTx from freepages, which could block when combined with the outer View transaction. Pass the active Tx into loadFreelist so reconstruction uses freepagesWithTx and skips opening a nested read transaction (fixes etcd-io#877). Signed-off-by: Vedant Madane <6527493+VedantMadane@users.noreply.github.com>
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Summary
Rebuilding an unsynced freelist from
Tx.checkusedfreepages(), which opened a nested read-only transaction viabeginTx. That interacted badly with callers such as etcd snapshotStatus, which runstx.Check()insidedb.Viewon one goroutine while the check goroutine tried to start another read transaction (issue #877).Change
freepagesWithTx(*Tx)and use the active check transaction for the scan instead of opening a nested transaction.loadFreelist(sharedReadTx *Tx);Tx.checkpassestx,Openpreload passesnil.Testing
go test ./...in the root module (core packages pass; failpoint package needs gofail build tags in this environment).Fixes #877