Re: [PATCH v3 07/10] mm/shmem_luo: Retrieve tmpfs files onto a tmpfs mount chosen by userspace

[David Matlack <dmatlack@google.com>]

On 2026-11-04 05:27 PM, Pratyush Yadav wrote:

> > + * If @flags contains unknown flags or O_PATH, if @mode contains unknown mode
> > + * bits, or if @dirfd is not on a tmpfs mount, the retrieve fails with -EINVAL.
> > + * If the file can't be created, the retrieve fails with the same errors as
> > + * open(). A retrieve that fails before the preserved contents are restored can
> > + * be retried.
> 
> How is userspace supposed to tell if preserved contents were restored?

Through the error code, like Pasha said on patch 3. I'll reword this in
v4 in terms of errors instead of kernel internals: errors from checking
the argument and creating the file, e.g. -EINVAL, -EBADF and the errors
that open() returns, can be retried after fixing the argument. Errors
while restoring the contents, e.g. -ENOMEM, or -ENOSPC when the contents
don't fit on the mount, are permanent, and retrieving the token again
returns the same error.

Thanks for the review. I'll address the rest in v4.