On Thu 27-07-17 16:06:37, Ross Zwisler wrote: > On Thu, Jul 27, 2017 at 03:12:40PM +0200, Jan Kara wrote: > > Add 'sync' argument to dax_iomap_fault(). It will be used to communicate > > the fact that synchronous fault is requested. > > I don't actually think you need to pass this 'sync' parameter around. I think > you can completely rely on IOMAP_F_NEEDSYNC being set in iomap.flags. The DAX > fault handlers can call ops->iomap_begin() and use that flag for all the > tests and make it our once source of truth. > > That flag also tells us that we are doing a write fault (from > ext4_iomap_begin()): > > if ((flags & IOMAP_FAULT) && (flags & IOMAP_WRITE) && IS_SYNC(inode) && > !jbd2_transaction_committed(EXT4_SB(inode->i_sb)->s_journal, > EXT4_I(inode)->i_datasync_tid)) > iomap->flags |= IOMAP_F_NEEDDSYNC; > > So conditionals like this from dax_iomap_pte_fault(): > > force_ro = (vmf->flags & FAULT_FLAG_WRITE) && sync && > (iomap.flags & IOMAP_F_NEEDDSYNC); > > can be simplified to: > > force_ro = (iomap.flags & IOMAP_F_NEEDDSYNC); Yeah, probably you're right. I'll look into changing this. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
