> > On Wed 09-01-19 19:26:05, Pankaj Gupta wrote: > > Virtio pmem provides asynchronous host page cache flush > > mechanism. We don't support 'MAP_SYNC' with virtio pmem > > and ext4. > > > > Signed-off-by: Pankaj Gupta <pagupta@xxxxxxxxxx> > ... > > @@ -371,6 +373,13 @@ static int ext4_file_mmap(struct file *file, struct > > vm_area_struct *vma) > > if (!IS_DAX(file_inode(file)) && (vma->vm_flags & VM_SYNC)) > > return -EOPNOTSUPP; > > > > + /* We don't support synchronous mappings with guest direct access > > + * and virtio based host page cache flush mechanism. > > + */ > > + if (IS_DAX(file_inode(file)) && virtio_pmem_host_cache_enabled(dax_dev) > > + && (vma->vm_flags & VM_SYNC)) > > + return -EOPNOTSUPP; > > + > > Shouldn't there rather be some generic way of doing this? Having > virtio_pmem_host_cache_enabled() check in filesystem code just looks like > filesystem sniffing into details is should not care about... Maybe just > naming this (or having a wrapper) dax_dev_map_sync_supported()? Thanks for the feedback. Just wanted to avoid 'dax' in function name just to differentiate this with real dax. But yes can add a wrapper: dax_dev_map_sync_supported() Thanks, Pankaj
