Simplify and fix cache volume locking #4352
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mtrmac
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This adds no new tests:
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Could we get this in first please #4349 and then we can rebase the current PR ? |
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Sure. The overlap is actually pretty small. |
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@mtrmac Could you rebase please :) |
They exist in memory anyway, so this is more efficient: we avoid the need to manually touch the filesystem again, the associated costs - and the error paths go away. [NO NEW TESTS NEEDED] Signed-off-by: Miloslav Trmač <[email protected]>
By construction it's now quite clear that the locks should always be locked. Don't even bother with AssertLockedForWriting(), that's partially (checking for lock ownership, not for read-write ownership) implied by Unlock() already. [NO NEW TESTS NEEDED] Signed-off-by: Miloslav Trmač <[email protected]>
Maintain a list of _all_ the locks, not just the last one. Signed-off-by: Miloslav Trmač <[email protected]>
It can return at most one lock, so don't return an array. Should not change behavior right now, but it will simplify cleanup. [NO NEW TESTS NEEDED] Signed-off-by: Miloslav Trmač <[email protected]>
rhatdan
reviewed
Oct 19, 2022
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Other then spelling mistake LGTM |
... and use a more traditional error handling model, where responsibility for the cleanup passes to the caller _only_ if the called function succeeds. To reinforce that, hard-code nil returns on error paths instead of returning the locks. Signed-off-by: Miloslav Trmač <[email protected]>
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: flouthoc, mtrmac The full list of commands accepted by this bot can be found here. The pull request process is described here
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What type of PR is this?
What this PR does / why we need it:
sharing=locked(an undocumented feature AFAICS): Pass around lock objects instead of files, completely eliminating various error pathsLockfile.Locked, which is going away in API break: Remove Lockfile.Locked storage#1399 ).How to verify it
Existing tests? I didn’t even try running the code.
Which issue(s) this PR fixes:
None
Special notes for your reviewer:
Cc: @flouthoc who added the feature in #3820.
Does this PR introduce a user-facing change?