Re: [PATCH v6 06/20] liveupdate: luo_file: implement file systems callbacks

On Tue, Nov 18 2025, David Matlack wrote:

On 2025-11-15 06:33 PM, Pasha Tatashin wrote:

quoted

This patch implements the core mechanism for managing preserved
files throughout the live update lifecycle. It provides the logic to
invoke the file handler callbacks (preserve, unpreserve, freeze,
unfreeze, retrieve, and finish) at the appropriate stages.

During the reboot phase, luo_file_freeze() serializes the final
metadata for each file (handler compatible string, token, and data
handle) into a memory region preserved by KHO. In the new kernel,
luo_file_deserialize() reconstructs the in-memory file list from this
data, preparing the session for retrieval.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>

quoted

+int liveupdate_register_file_handler(struct liveupdate_file_handler *h);

Should there be a way to unregister a file handler?

If VFIO is built as module then I think it  would need to be able to
unregister its file handler when the module is unloaded to avoid leaking
pointers to its text in LUO.

Good point. We also need when using FLB. You would first do
liveupdate_register_file_handler(), and then do
liveupdate_register_flb(). If the latter fails, you would want to
unregister the file handler too.

-- 
Regards,
Pratyush Yadav