HDDS-1672. Improve locking in OzoneManager. #1016
Merged
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
anuengineer
reviewed
Jun 26, 2019
Contributor
There was a problem hiding this comment.
nit: if acquireLock can return true , the you can write acquiredBucketLock = acquireLock, just eliminates 2 lines of code
|
💔 -1 overall
This message was automatically generated. |
|
💔 -1 overall
This message was automatically generated. |
|
💔 -1 overall
This message was automatically generated. |
bharatviswa504
force-pushed
the
HDDS-1672-1
branch
from
241369a to
61274f1
Compare
|
💔 -1 overall
This message was automatically generated. |
anuengineer
reviewed
Jun 27, 2019
| metadataManager.getLock().acquireVolumeLock(volumeName); | ||
| metadataManager.getLock().acquireBucketLock(volumeName, bucketName); | ||
| boolean acquiredBucketLock = false; | ||
| metadataManager.getLock().acquireLock(VOLUME_LOCK, volumeName); |
Contributor
There was a problem hiding this comment.
There is a subtle bug here. We either need to assume that acquireLock cannot fail, or assume that it can fail.
If it cannot fail: Then the finally is simple, you can release bucket and volume lock.
if it can fail: Then it is possible the acquire volume lock is going to fail -- and there is no handling -- I am presuming that it will throw up into the calling unction and there is some sort of a handler there ? if that is the case, what will it throw ? I am not sure it can fail -- @arp7 comments?
Contributor
There was a problem hiding this comment.
We have no option but to assume that it can fail for two reasons:
- Because of the following check:
public void acquireVolumeLock(String volume) {
// Calling thread should not hold any bucket lock.
// You can take an Volume while holding S3 bucket lock, since
// semantically an S3 bucket maps to the ozone volume. So we check here
// only if ozone bucket lock is taken.
if (hasAnyBucketLock()) {
throw new RuntimeException(
"Thread '" + Thread.currentThread().getName() +
"' cannot acquire volume lock while holding bucket lock(s).");
}
- The wrapped call to
lockPool.borrowObject()inLockManager#lockdeclares that it can throwException. So that covers pretty much any exception under the earth.
Contributor
Author
There was a problem hiding this comment.
If lock acquire fails, we get RunTimeException from underlying LockManager.
Contributor
There was a problem hiding this comment.
Looked at this further. Failure to get volume lock is fine here. It is up to the caller to release their resources when the stack is unwound.
Contributor
There was a problem hiding this comment.
I haven't looked at the entire patch however I am +1 on this particular point.
anuengineer
approved these changes
Jun 27, 2019
Contributor
anuengineer
left a comment
anuengineer
left a comment
There was a problem hiding this comment.
I am not sure that lock calls can fail. So we might have some spurious calls. But it is okay.
Contributor
Author
|
I reached out to @arp7 offline, he is fine with proceeding forward. |
Contributor
Author
|
Test failures are not related to this patch. |
Contributor
Author
|
Thank You @anuengineer for the review. |
bshashikant
pushed a commit
to bshashikant/hadoop
that referenced
this pull request
Jul 10, 2019
shanthoosh
added a commit
to shanthoosh/hadoop
that referenced
this pull request
Oct 15, 2019
…erface. (apache#1016) * Move StartpointVisitor to SystemAdmin.
amahussein
pushed a commit
to amahussein/hadoop
that referenced
this pull request
Oct 29, 2019
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 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.
Changes in this PR: