On Thu, Jun 11, 2020 at 01:37:26AM +0100, Al Viro wrote:
> On Wed, Jun 10, 2020 at 05:13:52PM -0700, Mike Kravetz wrote:
>
> > To address this issue,
> > - Add a new file operation f_real while will return the underlying file.
> > Only overlayfs provides a function for this operation.
> > - Add a new routine real_file() which can be used by core code get an
> > underlying file.
> > - Update is_file_hugepages to get the real file.
>
> Egads... So to find out whether it's a hugetlb you would
> * check if a method is NULL
> * if not, call it
> * ... and check if the method table of the result is hugetlbfs one?
>
> Here's a radical suggestion: FMODE_HUGEPAGES. Just have it set by
> ->open() and let is_file_hugepages() check it. In ->f_mode. And
> make the bloody hugetlbfs_file_operations static, while we are at it.
ITYM FMODE_OVL_UPPER. To quote Mike:
> while (file->f_op == &ovl_file_operations)
> file = file->private_data;
> return file;
which would be transformed into:
while (file->f_mode & FMODE_OVL_UPPER)
file = file->private_data;
return file;
Or are you proposing that overlayfs copy FMODE_HUGEPAGES from the
underlying fs to the overlaying fs?
