On Fri 27-10-17 08:43:01, Christoph Hellwig wrote: > On Thu, Oct 26, 2017 at 05:48:04PM +0200, Jan Kara wrote: > > But now that I look at XFS implementation again, it misses handling > > of VM_FAULT_NEEDSYNC in xfs_filemap_pfn_mkwrite() (ext4 gets this right). > > I'll fix this by using __xfs_filemap_fault() for xfs_filemap_pfn_mkwrite() > > as well since it mostly duplicates it anyway... Thanks for inquiring! > > My first patches move xfs_filemap_pfn_mkwrite to use __xfs_filemap_fault, > but that didn't work. Wish I'd remember why, though. Maybe due to the additional check on IS_DAX(inode) in __xfs_filemap_fault() which could do the wrong thing if per-inode DAX flag is switched? Because otherwise __xfs_filemap_fault(vmf, PE_SIZE_PTE, true) does exactly the same thing as xfs_filemap_pfn_mkwrite() did. If we do care about per-inode DAX flag switching, I can just fixup xfs_filemap_pfn_mkwrite() but my understanding was that we ditched the idea at least until someone comes up with a reliable way to implement that... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
