CA-402326: Fetch SM records from the pool in one go to avoid race #6127
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
Vincent-lau
force-pushed
the
private/shul2/sm-feature-check2
branch
3 times, most recently
from
d8fcb68 to
4feb8c5
Compare
|
Testing in progress |
Vincent-lau
changed the title
Vincent-lau
force-pushed
the
private/shul2/sm-feature-check2
branch
from
4feb8c5 to
630aead
Compare
last-genius
approved these changes
Nov 19, 2024
Previously the SM feature check was done in two parts, fetch all the SM ref from the coordinator, and then fetch their information such as types and features from the coordinator basedon the refs. This can cause race conditions, where the previously fetched refs might have been deleted when we fetch the SM features. The deletion might happen due to the way SM registeration works for shared SRs such as GFS2, where each `PBD.plug` will trigger a deregister of existing SM and re-register (which will delete existing SMs), and create another (very likely) identical SM. To avoid this race, instead of fetch SM refs and their features separately, do this in one go so we get a consistent snapshot of the db state. Also add a bit more debugging messages. Signed-off-by: Vincent Liu <shuntian.liu2@cloud.com>
lindig
approved these changes
Nov 19, 2024
edwintorok
reviewed
Nov 19, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
Previously the SM feature check was done in two parts, fetch all the SM ref from the coordinator, and then fetch their information such as types and features from the coordinator basedon the refs. This can cause race conditions, where the previously fetched refs might have been deleted when we fetch the SM features. The deletion might happen due to the way SM registeration works for shared SRs such as GFS2, where each
PBD.plugwill trigger a deregister of existing SM and re-register (which will delete existing SMs), and create another (very likely) identical SM.To avoid this race, instead of fetch SM refs and their features separately, do this in one go so we get a consistent snapshot of the db state.