[cinder-csi-plugin] Add mkfsOptions StorageClass parameter

[rybnico]

What this PR does / why we need it:

Add support for a new mkfsOptions StorageClass parameter that allows cluster admins to pass custom mkfs flags when formatting volumes. This is particularly useful for Ceph-backed storage where passing -E nodiscard to mkfs.ext4 can dramatically speed up provisioning (e.g. from ~7 minutes to seconds for a 100 GB volume).

The parameter value is comma-separated, with each token further split on whitespace to produce individual mkfs command-line arguments. Example: mkfsOptions: "-E nodiscard,-O ^metadata_csum"

Implementation:

• Extract mkfsOptions from StorageClass params in CreateVolume and pass via VolumeContext (both new-volume and idempotent early-return paths)
• Parse mkfsOptions in NodeStageVolume using parseMkfsOptions() helper
• Use FormatAndMountSensitiveWithFormatOptions() from k8s.io/mount-utils to pass format options separately from mount options
• No behavior change when mkfsOptions is not set

Which issue this PR fixes(if applicable):
fixes #3068

Special notes for reviewers:
Inspired by the Ceph CSI implementation (ceph/ceph-csi#621).

Release note:

NONE

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: rybnico / name: Nicolai Rybnikar (cbc2205)

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[kayrus]

/ok-to-test

[kayrus]

reading the https://github.com/kubernetes/utils/blob/28399d86e0b55e612b83ad94dc6bac8e5de2a5ac/mount/mount_linux.go#L396 source code it seems that this is not a mkfs option, but a mount option. Does it make sense to rename it?

[rybnico]

reading the https://github.com/kubernetes/utils/blob/28399d86e0b55e612b83ad94dc6bac8e5de2a5ac/mount/mount_linux.go#L396 source code it seems that this is not a mkfs option, but a mount option. Does it make sense to rename it?

No, it's an option for mkfs when formatting the device for the first time, not a mount option. We use the function FormatAndMountSensitiveWithFormatOptions from mount_linux.go and pass the mkfsOptions as the argument formatOptions. Since it's called mkfsOptions in Ceph CSI and other CSI controllers, I think it's the correct name for the field.

[kayrus]

No, it's an option for mkfs when formatting the device for the first time, not a mount option.

could you point me to the code that passes sensitiveOptions to mkfs? I've been looking but can't find it. from what I can see, this list is only used for mount options.

[rybnico]

No, it's an option for mkfs when formatting the device for the first time, not a mount option.

could you point me to the code that passes sensitiveOptions to mkfs? I've been looking but can't find it. from what I can see, this list is only used for mount options.

Of course - but we don't pass them as argument sensitiveOptions but rather formatOptions.

We create formatOptions from mkfsOptions here
We pass this as a new argument formatOptions to the formatAndMountRetry function here

In formatAndMountRetry, the formatOptions are passed to FormatAndMountSensitiveWithFormatOptions here and here.

In mount-utils, the options is finally passed to formatAndMountSensitive and added to the args in the call to mounter.format

[kayrus]

you can use

cloud-provider-openstack/pkg/util/util.go

Lines 175 to 182 in 9c80105

	// SplitTrim splits a string of values separated by sep rune into a slice of
	// strings with trimmed spaces.
	func SplitTrim(s string, sep rune) []string {
	f := func(c rune) bool {
	return unicode.IsSpace(c) || c == sep
	}
	return strings.FieldsFunc(s, f)
	}

[kayrus]

Thanks, got it. I mixed up sensitiveOptions and formatOptions. They were hidden in github UI, and I missed the formatOptions:

Next time I'll try to use a proper code viewer :)

[kayrus]

it makes sense to use kebab-case style here