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https://issues.apache.org/jira/browse/HDDS-1672?focusedWorklogId=263984&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-263984
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ASF GitHub Bot logged work on HDDS-1672:
----------------------------------------
Author: ASF GitHub Bot
Created on: 20/Jun/19 18:18
Start Date: 20/Jun/19 18:18
Worklog Time Spent: 10m
Work Description: anuengineer commented on pull request #949: HDDS-1672.
Improve locking in OzoneManager.
URL: https://github.com/apache/hadoop/pull/949#discussion_r295898352
##########
File path:
hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/om/OzoneManagerLock.java
##########
@@ -96,30 +112,39 @@ public OzoneManagerLock(Configuration conf) {
}
/**
- * Acquires user lock on the given resource.
+ * Acquires S3 Bucket lock on the given resource.
*
* <p>If the lock is not available then the current thread becomes
- * disabled for thread scheduling purposes and lies dormant until the
- * lock has been acquired.
+ * disabled for thread scheduling purposes and lies dormant until the lock
has
+ * been acquired.
*
- * @param user User on which the lock has to be acquired
+ * @param s3BucketName S3Bucket Name on which the lock has to be acquired
*/
- public void acquireUserLock(String user) {
- // Calling thread should not hold any volume or bucket lock.
- if (hasAnyVolumeLock() || hasAnyBucketLock() || hasAnyS3Lock()) {
+ public void acquireS3BucketLock(String s3BucketName) {
+ // Calling thread should not hold any volume/bucket/user lock.
+
+ // Not added checks for prefix/s3 secret lock, as they will never be
+ // taken with s3Bucket Lock. In this way, we can avoid 2 checks every
+ // time we acquire s3Bucket lock.
+
+ // Or do we need to add this for future safe?
+
+ if (hasAnyVolumeLock() || hasAnyBucketLock() || hasAnyUserLock()) {
Review comment:
if we do the bitmap trick, we can write a generic function that looks like
this , hasAnyHigherLocks(UserLock), and this can check from 1-5 -- which is a
series of simple xor operations and return the value. All we care is if the
lock has been taken; so a simple bit map for each thread is all we need.
Assuming that our lock hierarchy would not cross 32 locking levels
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Issue Time Tracking
-------------------
Worklog Id: (was: 263984)
Time Spent: 3h (was: 2h 50m)
> Improve locking in OzoneManager
> -------------------------------
>
> Key: HDDS-1672
> URL: https://issues.apache.org/jira/browse/HDDS-1672
> Project: Hadoop Distributed Data Store
> Issue Type: Improvement
> Components: Ozone Manager
> Affects Versions: 0.4.0
> Reporter: Bharat Viswanadham
> Assignee: Bharat Viswanadham
> Priority: Major
> Labels: pull-request-available
> Attachments: Ozone Locks in OM.pdf
>
> Time Spent: 3h
> Remaining Estimate: 0h
>
> In this Jira, we shall follow the new lock ordering. In this way, in volume
> requests we can solve the issue of acquire/release/reacquire problem. And few
> bugs in the current implementation of S3Bucket/Volume operations.
>
> Currently after acquiring volume lock, we cannot acquire user lock.
> This is causing an issue in Volume request implementation,
> acquire/release/reacquire volume lock.
>
> Case of Delete Volume Request:
> # Acquire volume lock.
> # Get Volume Info from DB
> # Release Volume lock. (We are releasing the lock, because while acquiring
> volume lock, we cannot acquire user lock0
> # Get owner from volume Info read from DB
> # Acquire owner lock
> # Acquire volume lock
> # Do delete logic
> # release volume lock
> # release user lock
>
> We can avoid this acquire/release/reacquire lock issue by making volume lock
> as low weight.
>
> In this way, the above deleteVolume request will change as below
> # Acquire volume lock
> # Get Volume Info from DB
> # Get owner from volume Info read from DB
> # Acquire owner lock
> # Do delete logic
> # release owner lock
> # release volume lock.
> Same issue is seen with SetOwner for Volume request also.
> During HDDS-1620 [~arp] brought up this issue.
> I am proposing the above solution to solve this issue. Any other
> idea/suggestions are welcome.
> This also resolves a bug in setOwner for Volume request.
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