HDDS-13783. Implement locks for OmSnapshotLocalDataManager by swamirishi · Pull Request #9140 · apache/ozone

swamirishi · 2025-10-12T00:43:31Z

What changes were proposed in this pull request?

Locks need to be taken while updating the LocalSnapshotData yaml file which is important to avoid race conditions with other threads reading the yaml contents.
This depends on #9159 #9160

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-13783

How was this patch tested?

Adding additional unit tests

Change-Id: Iba47aeb21663dfa407ab71339cef02c0d74b49f2

Change-Id: Ifd2feca1fddb144e4955db025f0b15a2ab1f3bfe

Change-Id: I34536ff06efb7d5a4942853f0fd83942ab398b5f

…otLocalDataManager Change-Id: I34536ff06efb7d5a4942853f0fd83942ab398b5f

Change-Id: I32bcaf2a1fb290f1790c02872a0230cd65586636

Change-Id: I105a2e8178c0444d52de41b99801f4ceb6d57ffd # Conflicts: # hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/util/Checksum.java # hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/util/ObjectSerializer.java # hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/util/YamlSerializer.java # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotLocalDataYaml.java # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java # hadoop-ozone/ozone-manager/src/test/java/org/apache/hadoop/ozone/om/TestOmSnapshotLocalDataYaml.java

Change-Id: I985170e38fb8beeb784048e85a08a4c79e1aec97

Change-Id: I33e6e6e825bf23c323ad7ed593d800a11720fa4f

Change-Id: If30b2c766db82adde72145c8ecd3e590ef54cc2d

Change-Id: Id3f2c49050bc3476b9e0f5f51dacb6d9acc4c2f7

Change-Id: I432960725b4c6c55aa906b5780cc3027e41e10db

Change-Id: I3c5514e5bbd251a2b5297d8f074cfde5c71fa543

Change-Id: Ib5a9e6c91bdccba17820263c47eaf2c8400e930d

Change-Id: Ica36e0615c7bc6aa9b6a7f6fafafd0f830d4bafb

Change-Id: I26b66f266bb7677e4b1078f5fcd9f2ce3a651a70 # Conflicts: # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

Change-Id: I1d93dbc048a42cc55ff1f8ffa420e52f967527b8

Change-Id: I34202928a7a367dd0a1e57219317ff34de352b78

Change-Id: Iad6f26cb71ec921c51ee2d138745df1a2663533f

Change-Id: Ic5f7e249cfb9cb3973cbcd4abd36b22a6ff8f5aa

…calDataProvider Change-Id: I3a004b4b435075a4348960aeed642e8da71e7e72

Change-Id: I06990bc9ab8fc7e1eb7bec255646a650bd8c35fe

Change-Id: I4c6c61c83aa9fadab8ecef854b99dcc0a89a2208

Change-Id: I0e476322372a302572f1fe79cbf2e874bfeac2ed

Change-Id: I3849387d064e093634e69cdaf870d27c1934cda5 # Conflicts: # hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/util/ObjectSerializer.java # hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/util/YamlSerializer.java # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotLocalData.java # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotLocalDataYaml.java # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotManager.java # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

Change-Id: Ie5e5f3dab4324103e8855dd15619d7755f0422e6

Change-Id: I55bd5c3ef7fc32910a9111328638de2edffcd541

Copilot

Pull Request Overview

Implements lock management for OmSnapshotLocalDataManager to avoid race conditions when reading/writing snapshot local YAML, and refactors APIs to return scoped providers that hold locks during use.

Introduces Readable/Writable provider classes that acquire hierarchical locks per snapshot and resolve version mapping along the snapshot chain.
Adds a fullLock (ReadWriteLock) for protecting in-memory graph/version metadata and atomically writes YAML via temp file + atomic move.
Updates tests to validate lock acquisition/release order and version resolution/validation; adds new FlatResource.SNAPSHOT_LOCAL_DATA_LOCK.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java	Core changes: locking, provider classes, version resolution logic, atomic commit, and validation.
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotLocalData.java	Changes API for addVersionSSTFileInfos to take LiveFileMetaData, adds removal method and setter on VersionMeta.
hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/om/lock/FlatResource.java	Adds SNAPSHOT_LOCAL_DATA_LOCK for per-snapshot YAML operations.
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/SnapshotDefragService.java	Uses Readable provider in try-with-resources for safe access.
hadoop-ozone/ozone-manager/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOmSnapshotLocalDataManager.java	Extensive new tests for lock ordering, version resolution/validation, and updated APIs.
hadoop-ozone/ozone-manager/src/test/java/org/apache/hadoop/ozone/om/TestOmSnapshotManager.java	Ensures previous snapshot IDs are null for idempotent snapshot creation tests.
hadoop-ozone/ozone-manager/src/test/java/org/apache/hadoop/ozone/om/TestOmSnapshotLocalDataYaml.java	Adjusts tests to provide LiveFileMetaData instead of SstFileInfo.

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Copilot · 2025-10-17T15:27:24Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+              for (Map.Entry<Integer, LocalDataVersionNode> entry : previousVersionNodeMap.entrySet()) {
+                Set<LocalDataVersionNode> versionNode = localDataGraph.successors(entry.getValue());
+                if (versionNode.size() > 1) {
+                  throw new IOException(String.format("Snapshot %s version %d has multiple successors %s",
+                      currentIteratedSnapshotId, entry.getValue(), versionNode));
+                }
+                if (versionNode.isEmpty()) {
+                  throw new IOException(String.format("Snapshot %s version %d doesn't have successor",
+                      currentIteratedSnapshotId, entry.getValue()));
+                }
+                // Set the version node for iterated version to the successor corresponding to the previous snapshot id.
+                entry.setValue(versionNode.iterator().next());


The graph is built with edges from a snapshot version to its previous version (current -> previous). To walk 'forward' along the chain from a previous snapshot to its dependent, you must use predecessors(), not successors(). Using successors() here will either return empty or the wrong node, breaking version resolution. Replace successors(...) with predecessors(...), and update the error messages accordingly.

Copilot · 2025-10-17T15:27:24Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+    private WritableOmSnapshotLocalDataProvider(UUID snapshotId) throws IOException {
+      super(snapshotId, false);
+      fullLock.readLock().lock();
+    }
+
+    private WritableOmSnapshotLocalDataProvider(UUID snapshotId, UUID snapshotIdToBeResolved) throws IOException {
+      super(snapshotId, false, null, snapshotIdToBeResolved, true);
+      fullLock.readLock().lock();
+    }


WritableOmSnapshotLocalDataProvider acquires fullLock.readLock() while performing mutations (commit/upsert) to versionNodeMap/localDataGraph. This can race with readers and other writers. Use fullLock.writeLock() for writes and hold fullLock.readLock() in ReadableOmSnapshotLocalDataProvider during graph reads. Specifically: change readLock() to writeLock() in these constructors and in close(); and acquire/release fullLock.readLock() in ReadableOmSnapshotLocalDataProvider to protect versionNodeMap/localDataGraph access.

Copilot · 2025-10-17T15:27:24Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+    @Override
+    public void close() throws IOException {
+      super.close();
+      fullLock.readLock().unlock();


WritableOmSnapshotLocalDataProvider acquires fullLock.readLock() while performing mutations (commit/upsert) to versionNodeMap/localDataGraph. This can race with readers and other writers. Use fullLock.writeLock() for writes and hold fullLock.readLock() in ReadableOmSnapshotLocalDataProvider during graph reads. Specifically: change readLock() to writeLock() in these constructors and in close(); and acquire/release fullLock.readLock() in ReadableOmSnapshotLocalDataProvider to protect versionNodeMap/localDataGraph access.

Suggested change

fullLock.readLock().unlock();

fullLock.writeLock().unlock();

We need a readLock here since we are already acquiring locks on individual snapshots. This lock is for race condition between bootstrap and other creates

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotLocalData.java

Copilot · 2025-10-17T15:27:25Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+    }
+
+    /**
+     * Intializer the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the


Corrected spelling of 'Intializer' to 'Initializes'.

Suggested change

* Intializer the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the

* Initializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the

Copilot · 2025-10-17T15:27:26Z

...anager/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOmSnapshotLocalDataManager.java

+          "key1", "key2")), 3);
+
+      IOException ex = assertThrows(IOException.class, omSnapshotLocalDataProvider::commit);
+      System.out.println(ex.getMessage());


Avoid printing to stdout in unit tests; it adds noise to test logs. Please remove the System.out.println(...) line.

Suggested change

System.out.println(ex.getMessage());

Change-Id: I165f00132548acf920b8fb9d7530a6314366797d

Change-Id: I3df543d896463f24ba3b69fce1b2f655af612dc6

Change-Id: I94cf4b82b2b620f480e2d1e01e6d94a6679d974e

Change-Id: I661e61e04031c1bcd537024e0a0859a6d6aeaffd

Change-Id: I59cab67d93f0359bca54c0c8119f5018167b7d1a

Change-Id: I950b4d0cc45a74369b8efa36deaf947db4cb35bc

Change-Id: Ib21e10e8fdf518928f238c9daae6672d679b7ae4

This reverts commit 48ec0bb.

Change-Id: I37d2f5c07f405f3069a4cb99881d5d1e67110e79

Change-Id: I119e8cede140c755d3cd09c0a56234ff4906be98

Change-Id: I6bbcdac1acb389ee3c08efb37676cccdb3d783c6

smengcl · 2025-10-24T03:13:45Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

@@ -75,6 +93,7 @@ public void computeAndSetChecksum(Yaml yaml, OmSnapshotLocalData data) throws IO
      }
    };
    this.versionNodeMap = new HashMap<>();


Is ConcurrentHashMap better?

We need not use ConcurrentHashMap since graph is not concurrent and can be only updated inside a synchrnized block. If you see both the Map and graph data structure only gets updated in the upsertNode function which is synchronized

If we don't use ConcurrentHashMap, all read path also need to be in synchronized, otherwise other threads may not see the write result.

why so? We are always acquiring a readLock or write lock before accessing the map. We cannot access his in a thread safe way anyhow without acquiring lock

We can read in parallel when there is no write lock involved

locking is good but lock alone may not be sufficient.

see Java memory model. related: https://stackoverflow.com/a/15794355

Yeah I have synchornized reads and writes on concurrentHashMap and localDataGraph using an internalReadWriteLock

Change-Id: I36c48585d17042491f7dc61a84845c999802d1fa

smengcl · 2025-10-24T04:11:54Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+  private HierarchicalResourceLockManager locks;

  public OmSnapshotLocalDataManager(OMMetadataManager omMetadataManager) throws IOException {
    this.localDataGraph = GraphBuilder.directed().build();


The same applies to localDataGraph

Unfortunately there is no concurrent graph data structure implementation library. We will have to implement one I feel this might be an overkill

I agree.

Just make sure all r/w to this graph are in synchronized then we should be good.

I have made all writes and reads synchronized by using a readWrite lock

Change-Id: I2f7cb5ec772d2d2de99e8d3cba8bdc34e3f36efd

Change-Id: Ida628ebab658b2a31fe5d654f19035e96f3163ac

Change-Id: I960fd1d25e0f323d56f5e88ffb03261d777d9021

Copilot

Pull Request Overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

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Copilot · 2025-10-29T03:56:08Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+    }
+
+    /**
+     * Intializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the


Corrected spelling of 'Intializes' to 'Initializes'.

Suggested change

* Intializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the

* Initializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the

Copilot · 2025-10-29T03:56:08Z

...anager/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOmSnapshotLocalDataManager.java

+   * Depending on read or write locks are acquired on the snapshotId and read lock is acquired on the previous
+   * snapshot. Once the instance is closed the read lock on previous snapshot is released followed by releasing the
+   * lock on the snapshotId.
+   * @param read


The @param 'read' lacks a description. Add a description such as '@param read if true, acquire read lock; if false, acquire write lock'.

Suggested change

* @param read

* @param read if true, acquire read lock; if false, acquire write lock

Copilot · 2025-10-29T03:56:09Z

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

+    if (versionNode != null && localDataGraph.inDegree(versionNode) != 0) {
+      Set<LocalDataVersionNode> versionNodes = localDataGraph.predecessors(versionNode);
+      throw new IOException(String.format("Cannot remove Snapshot %s with version : %d since it still has " +
+          "predecessors : %s", snapshotId, version, versionNodes));


The error message uses 'predecessors' when referring to nodes that depend on this version. Based on the logic checking inDegree, these are actually successors (dependents). Consider changing 'predecessors' to 'successors' or 'dependents' for clarity.

Suggested change

"predecessors : %s", snapshotId, version, versionNodes));

"successors : %s", snapshotId, version, versionNodes));

Copilot · 2025-10-29T03:56:09Z

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotLocalData.java

@@ -274,7 +279,7 @@ public OmSnapshotLocalData copyObject() {
   * maintain immutability.
   */
  public static class VersionMeta implements CopyObject<VersionMeta> {


The field previousSnapshotVersion is changed from final to mutable without a clear design comment explaining why mutability is required. Consider adding a comment explaining the use case for mutation (appears to be for version resolution during lock acquisition).

Suggested change

public static class VersionMeta implements CopyObject<VersionMeta> {

public static class VersionMeta implements CopyObject<VersionMeta> {

/**

* The version of the previous snapshot. This field is mutable to allow

* version resolution during lock acquisition and other update scenarios.

* Although the class is generally intended to be immutable, mutability

* of this field is required for certain internal operations where the

* previous snapshot version may need to be updated after object creation.

*/

...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

smengcl

lgtm

Change-Id: I1bb9832e7e8c40deeccb9d0868eaf5772f39b7f9

swamirishi · 2025-10-29T06:19:22Z

Thank you @smengcl & @jojochuang for reviewing the PR

adoroszlai · 2025-11-03T08:17:46Z

@swamirishi please set fix version when resolving Jira issue after PR merge

swamirishi added 11 commits October 8, 2025 09:39

HDDS-13765. SnapshotLocalData yaml should also track snapshotId

6e241f6

Change-Id: Iba47aeb21663dfa407ab71339cef02c0d74b49f2

HDDS-13627. In memory Manager for Snapshot Local Data

a869500

Change-Id: Ifd2feca1fddb144e4955db025f0b15a2ab1f3bfe

HDDS-13627. In memory Manager for Snapshot Local Data

252d338

Change-Id: I34536ff06efb7d5a4942853f0fd83942ab398b5f

HDDS-13767. Refactor SnapshotLocalDataYaml related code into OmSnapsh…

4099bc6

…otLocalDataManager Change-Id: I34536ff06efb7d5a4942853f0fd83942ab398b5f

HDDS-13767. Fix pmd

e02670c

Change-Id: I32bcaf2a1fb290f1790c02872a0230cd65586636

HDDS-13627. Fix checkstyle

79580e9

Change-Id: I985170e38fb8beeb784048e85a08a4c79e1aec97

Merge remote-tracking branch 'apache/master' into HEAD

2a331ef

Change-Id: I33e6e6e825bf23c323ad7ed593d800a11720fa4f

Merge remote-tracking branch 'apache/master' into HEAD

c4f69e2

Change-Id: If30b2c766db82adde72145c8ecd3e590ef54cc2d

HDDS-13627. Add tests

afbc592

Change-Id: Id3f2c49050bc3476b9e0f5f51dacb6d9acc4c2f7

HDDS-13783. Implement locks for OmSnapshotLocalDataManager

70ac2c7

Change-Id: I432960725b4c6c55aa906b5780cc3027e41e10db

swamirishi changed the title ~~HDDS-13783.~~ HDDS-13783. Implement locks for OmSnapshotLocalDataManager Oct 12, 2025

swamirishi requested review from jojochuang and smengcl October 12, 2025 00:43

swamirishi added 11 commits October 11, 2025 20:49

HDDS-13783. Implement locks for OmSnapshotLocalDataManager

b554cc7

Change-Id: I3c5514e5bbd251a2b5297d8f074cfde5c71fa543

HDDS-13783. Refactor inline variable

49eccfa

Change-Id: Ib5a9e6c91bdccba17820263c47eaf2c8400e930d

HDDS-13627. Refactor map data structure

51eda04

Change-Id: Ica36e0615c7bc6aa9b6a7f6fafafd0f830d4bafb

Merge remote-tracking branch 'origin/HDDS-13627' into HEAD

25f766c

Change-Id: I26b66f266bb7677e4b1078f5fcd9f2ce3a651a70 # Conflicts: # hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java

HDDS-13783. Add more condition to upsert

96689fa

Change-Id: I1d93dbc048a42cc55ff1f8ffa420e52f967527b8

HDDS-13783. Add java doc comment

0674299

Change-Id: I34202928a7a367dd0a1e57219317ff34de352b78

HDDS-13783. Add java doc comment

5d9fc49

Change-Id: Iad6f26cb71ec921c51ee2d138745df1a2663533f

HDDS-13783. Implement full lock

2d88176

Change-Id: Ic5f7e249cfb9cb3973cbcd4abd36b22a6ff8f5aa

HDDS-13783. Refactor and move modify method into WritableOmSnapshotLo…

a3c4c69

…calDataProvider Change-Id: I3a004b4b435075a4348960aeed642e8da71e7e72

HDDS-13783. Make full lock non static

686d0c7

Change-Id: I06990bc9ab8fc7e1eb7bec255646a650bd8c35fe

HDDS-13783. Fix remove

491a54b

Change-Id: I4c6c61c83aa9fadab8ecef854b99dcc0a89a2208

swamirishi added the snapshot https://issues.apache.org/jira/browse/HDDS-6517 label Oct 13, 2025

swamirishi added 4 commits October 13, 2025 17:35

HDDS-13627. Fix findbugs

5e69ee9

Change-Id: I0e476322372a302572f1fe79cbf2e874bfeac2ed

HDDS-13627. Fix tests

a95604e

Change-Id: Ie5e5f3dab4324103e8855dd15619d7755f0422e6

HDDS-13627. remove checksum interface

5a90fcf

Change-Id: I55bd5c3ef7fc32910a9111328638de2edffcd541

jojochuang requested a review from Copilot October 17, 2025 15:24

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swamirishi added 11 commits October 17, 2025 13:23

HDDS-13783. Add dirty bit

278605a

Change-Id: I165f00132548acf920b8fb9d7530a6314366797d

HDDS-13783. Address review comments

cf19dce

Change-Id: I3df543d896463f24ba3b69fce1b2f655af612dc6

HDDS-13783. Address review comments

34097de

Change-Id: I94cf4b82b2b620f480e2d1e01e6d94a6679d974e

HDDS-13783. Address review comments

c46ddc2

Change-Id: I661e61e04031c1bcd537024e0a0859a6d6aeaffd

HDDS-13783. Address review comments

99afc02

Change-Id: I59cab67d93f0359bca54c0c8119f5018167b7d1a

HDDS-13810. Fix Build Issue because of unused dependency

48ec0bb

Change-Id: I950b4d0cc45a74369b8efa36deaf947db4cb35bc

Merge remote-tracking branch 'origin/HDDS-13810' into HEAD

f524cad

Change-Id: Ib21e10e8fdf518928f238c9daae6672d679b7ae4

Revert "HDDS-13810. Fix Build Issue because of unused dependency"

cb31b7c

This reverts commit 48ec0bb.

HDDS-13783. Add case for commit key in middle of chain

8b014dd

Change-Id: I37d2f5c07f405f3069a4cb99881d5d1e67110e79

HDDS-13783. Convert set to list of predecessors

57662c6

Change-Id: I119e8cede140c755d3cd09c0a56234ff4906be98

Merge remote-tracking branch 'apache/master' into HEAD

79a46f4

Change-Id: I6bbcdac1acb389ee3c08efb37676cccdb3d783c6

This was referenced Oct 24, 2025

HDDS-13833. Add transactionInfo field in SnapshotLocalData and update the value on SnapshotPurgeRequest #9193

Merged

HDDS-13785. Remove orphan versions from SnapshotLocalData Yaml file #9150

Merged

smengcl reviewed Oct 24, 2025

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Merge remote-tracking branch 'apache/master' into HEAD

aa6facf

Change-Id: I36c48585d17042491f7dc61a84845c999802d1fa

smengcl reviewed Oct 24, 2025

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HDDS-13783. Make local data graph synchrnous

cc35056

Change-Id: I2f7cb5ec772d2d2de99e8d3cba8bdc34e3f36efd

swamirishi requested a review from sadanand48 October 27, 2025 15:33

swamirishi added 2 commits October 27, 2025 12:19

Merge remote-tracking branch 'apache/master' into HEAD

95341dd

Change-Id: Ida628ebab658b2a31fe5d654f19035e96f3163ac

HDDS-13783. Fix NPE with concurrentHashMap

616bef3

Change-Id: I960fd1d25e0f323d56f5e88ffb03261d777d9021

smengcl requested a review from Copilot October 29, 2025 03:48

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...ne-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/OmSnapshotLocalDataManager.java Show resolved Hide resolved

smengcl approved these changes Oct 29, 2025

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HDDS-13783. Add comments for localDataGraph

4596386

Change-Id: I1bb9832e7e8c40deeccb9d0868eaf5772f39b7f9

swamirishi merged commit b39bac0 into apache:master Oct 29, 2025
43 checks passed

	* Intializer the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the
	* Initializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the

	* Intializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the
	* Initializes the snapshot local data by acquiring the lock on the snapshot and also acquires a read lock on the

	* @param read
	* @param read if true, acquire read lock; if false, acquire write lock

	"predecessors : %s", snapshotId, version, versionNodes));
	"successors : %s", snapshotId, version, versionNodes));

-  public static class VersionMeta implements CopyObject<VersionMeta> {
+  public static class VersionMeta implements CopyObject<VersionMeta> {
+    /**
+     * The version of the previous snapshot. This field is mutable to allow
+     * version resolution during lock acquisition and other update scenarios.
+     * Although the class is generally intended to be immutable, mutability
+     * of this field is required for certain internal operations where the
+     * previous snapshot version may need to be updated after object creation.
+     */

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swamirishi commented Oct 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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swamirishi Oct 28, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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swamirishi commented Oct 29, 2025

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swamirishi commented Oct 12, 2025 •

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swamirishi Oct 28, 2025 •

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