Update the dataset name in handle after zfs_rename

[usaleem-ix]

Motivation and Context

For zfs_rename(), after the dataset name is successfully updated, the dataset handle that was passed to zfs_rename(), still contains the old name, due to which, the dataset handle becomes invalid. The following operations performed using this handle result in error since the dataset with old name cannot be found anymore.

changelist_rename() does update the names in dataset handles, but those are temporary handles that were created during changelist_gather(). The original handle that was used to call zfs_rename() is not updated.

Description

We should update the name in original ZFS handle after the IOCTL for rename returns success for the operation.

How Has This Been Tested?

Manually tested the rename operation for datasets and snapshots, including the recursive operation and via ZTS.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.