File clones and snapshots

When a snapshot is created and a file clone is subsequently updated, the previous state of the file clone will be saved in the snapshot.

When reading a file clone in the snapshot, the system will distinguish between the states of the clone:

The data block has not been modified since the snapshot was taken, so look for the data in the same file in the next most recent snapshot or active file system.
The file clone was updated, which indicates that the corresponding data block should be found in the clone parent. The system will look for the data in the clone parent within the same snapshot.

When a snapshot has file clones, those file clones should be deleted or split from their clone parents prior to deleting the snapshot. For more information, see Deleting file clones and Splitting file clones from clone parents. A policy file can be created to help determine if a snapshot has file clones. For more information, see File clones and policy files.