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fix: correctly identify alluxio root mount path in multi-mount datasets #6103

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fix: correctly identify alluxio root mount path in multi-mount datasets #6103

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10 changes: 5 additions & 5 deletions pkg/utils/ufs_path_builder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -47,18 +47,18 @@ func (u UFSPathBuilder) GenUFSPathInUnifiedNamespace(mount datav1alpha1.Mount) s
// GenAlluxioUFSRootPath determines which mount point should be mounted on the root path of
// the [unified namespace] in Alluxio engine. Commonly there are two cases:
//
// 1. If a `mount` item is the only item defined in `dataset.sepc.mounts[*]` and its ufs path equals to "/", its `mountpoint` should be on the root path.
// 1. If any `mount` item defined in `dataset.spec.mounts[*]` has its ufs path equal to "/", its `mountpoint` should be on the root path.
// e.g. alluxio fs mount s3://mybucket /
// 2. Otherwise, pick `/underFSStorage` as the default root path.
// e.g. alluxio fs mount /underFSStorage / && alluxio fs mount s3://mybucket /mybucket
//
// [unified namespace]: https://docs.alluxio.io/os/user/stable/en/core-services/Unified-Namespace.html
func (u UFSPathBuilder) GenAlluxioUFSRootPath(items []datav1alpha1.Mount) (string, *datav1alpha1.Mount) {

@gemini-code-assist gemini-code-assist Bot Jul 8, 2026

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medium

The documentation comment for GenAlluxioUFSRootPath (lines 50-53) is now outdated. It still states that the root path is only used if there is only a single mount item defined in dataset.spec.mounts. Since this PR enables identifying the root path in multi-mount scenarios, please update the documentation comment to reflect this new behavior.

if len(items) == 1 {
m := items[0]
for i := range items {
m := &items[i]
// only iff m matches all of the two following conditions (1) m is not a fluid-native mount point; (2) m.Path is "/", it should be the root path in cache UFS.
if !common.IsFluidNativeScheme(m.MountPoint) && u.GenUFSPathInUnifiedNamespace(m) == common.RootDirPath {
return m.MountPoint, &m
if !common.IsFluidNativeScheme(m.MountPoint) && u.GenUFSPathInUnifiedNamespace(*m) == common.RootDirPath {
return m.MountPoint, m
}
}
Comment on lines +57 to 63

@gemini-code-assist gemini-code-assist Bot Jul 8, 2026

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medium

Returning a pointer directly to the slice element (&items[i]) can lead to accidental mutations of the original slice elements (which typically belong to dataset.Spec.Mounts in Kubernetes controllers). This breaks the read-only assumption of the spec and can cause subtle bugs or unexpected reconciliations.

To prevent this, copy the slice element by value first, and then return a pointer to the copy (which will be safely allocated on the heap by Go's escape analysis). This also simplifies the code by avoiding the need to dereference *m when calling GenUFSPathInUnifiedNamespace.

Suggested change
for i := range items {
m := &items[i]
// only iff m matches all of the two following conditions (1) m is not a fluid-native mount point; (2) m.Path is "/", it should be the root path in cache UFS.
if !common.IsFluidNativeScheme(m.MountPoint) && u.GenUFSPathInUnifiedNamespace(m) == common.RootDirPath {
return m.MountPoint, &m
if !common.IsFluidNativeScheme(m.MountPoint) && u.GenUFSPathInUnifiedNamespace(*m) == common.RootDirPath {
return m.MountPoint, m
}
}
for i := range items {
m := items[i]
// only iff m matches all of the two following conditions (1) m is not a fluid-native mount point; (2) m.Path is "/", it should be the root path in cache UFS.
if !common.IsFluidNativeScheme(m.MountPoint) && u.GenUFSPathInUnifiedNamespace(m) == common.RootDirPath {
return m.MountPoint, &m
}
}


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16 changes: 16 additions & 0 deletions pkg/utils/ufs_path_builder_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,22 @@ func TestGenUFSRootPathForAlluxio(t *testing.T) {
wantMount *datav1alpha1.Mount
wantRootPath string
}{
"test multi mount item with root path": {
mounts: append(
mockMountSingleItem("spark", "https://mirrors.bit.edu.cn/apache/spark/", ""),
datav1alpha1.Mount{
Name: "flink",
MountPoint: "https://mirrors.bit.edu.cn/apache/flink/",
Path: "/",
},
),
wantRootPath: "https://mirrors.bit.edu.cn/apache/flink/",
wantMount: &datav1alpha1.Mount{
Name: "flink",
MountPoint: "https://mirrors.bit.edu.cn/apache/flink/",
Path: "/",
},
},
"test multi mount item case 1": {
mounts: mockMountMultiItems(mockMountSingleItem("spark", "local://mnt/local/path", "")),
wantRootPath: "/underFSStorage",
Expand Down
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