On Wed, Oct 17, 2018 at 01:36:52AM -0700, Christoph Hellwig wrote:
> > /* Update inode timestamps and remove security privileges when remapping. */
> > @@ -2023,7 +2034,8 @@ loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
> > {
> > loff_t ret;
> >
> > - WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP));
> > + WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
> > + REMAP_FILE_CAN_SHORTEN));
>
> I guess this is where you could actually use REMAP_FILE_VALID_FLAGS..
>
> > /* REMAP_FILE flags taken care of by the vfs. */
> > -#define REMAP_FILE_ADVISORY (0)
> > +#define REMAP_FILE_ADVISORY (REMAP_FILE_CAN_SHORTEN)
>
> And btw, they are not 'taken care of by the VFS', they need to be
> taken care of by the fs (possibly using helpers) to take affect,
> but they can be safely ignored.
Ok, I'll update the comment.
> > + if (!IS_ALIGNED(count, bs)) {
> > + if (remap_flags & REMAP_FILE_CAN_SHORTEN)
> > + count = ALIGN_DOWN(count, bs);
> > + else
> > + return -EINVAL;
>
> if (!(remap_flags & REMAP_FILE_CAN_SHORTEN))
> return -EINVAL;
> count = ALIGN_DOWN(count, bs);
Seeing as we return EINVAL on shortened count and !CAN_SHORTEN below
this, I think this can be simplified further:
if (pos_in + count == size_in) {
bcount = ALIGN(size_in, bs) - pos_in;
} else {
if (!IS_ALIGNED(count, bs))
count = ALIGN_DOWN(count, bs);
bcount = count;
}
--D
