Backport CA-419840 mark CD VBD as empty when its VDI is removed #6844
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
gthvn1
reviewed
Jan 19, 2026
| (* CA-419840 mark VBD as empty when it is a CDR *) | ||
| ( Db.VDI.get_VBDs ~__context ~self:vdi |> function | ||
| | [] -> | ||
| () (* should not happen *) |
Contributor
There was a problem hiding this comment.
Shouldn’t this be logged as a warning so we can catch it if it happens and inspect the situation? Or we can safely ignore it if it happens so a comment is fine ?
Contributor
Author
There was a problem hiding this comment.
In other places we are using fst; I don't expect a VDI not ever having anything but one VBD. But yeah, I could add a warning..
Contributor
Author
There was a problem hiding this comment.
Let's do that on the original PR, though. This one has problems with the CI, too.
When a CDR is removed from an ISO SR the corresponding VDI is deleted. This is not obvious in the logs because some logs refer to the VDI by reference and others by UUID. Tie this together. Signed-off-by: Christian Lindig <[email protected]>
When a CDR is removed from an ISO SR the corresponding VDI is deleted. So far we relied on the DB GC to mark the VBD as empty. This creates a window for a race where the VDI/CD is reported as present when in fact it is not. So mark the VBD as empty as early as possible. Signed-off-by: Christian Lindig <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When a CDR is removed from an ISO SR the corresponding VDI is deleted.
So far we relied on the DB GC to mark the VBD as empty. This creates a
window for a race where the VDI/CD is reported as present when in fact
it is not. So mark the VBD as empty as early as possible.