On Fri 30-09-16 01:59:05, Christoph Hellwig wrote: > On Tue, Sep 27, 2016 at 06:43:29PM +0200, Jan Kara wrote: > > Hello, > > > > these patches fix races when invalidating hole pages in DAX mappings. See > > changelogs for details. The series is based on my patches to write-protect > > DAX PTEs because we really need to closely track dirtiness (and cleanness!) > > of radix tree entries in DAX mappings in order to avoid discarding valid > > dirty bits leading to missed cache flushes on fsync(2). > > Except for the VM magic I don't feel qualified to review this looks fine > to me. But don't we need to switch ext4 away from going through the DIO > path first before the limited invalidation is effective there? > Otherwise we'll still get the full range invalidation from > generic_file_direct_write? After patch 5/6 the additional invalidation we get from generic_file_direct_write() for ext4 is racy but not doing any harm since we later do a reliable invalidation directly from dax_io() which patch 6/6 takes care to update. So it will be inefficient but it will work. Once ext4 is converted we get rid of this redundancy. BTW I have locally patches that avoid this inefficiency for ext4 but I figured there's no point in posting them since we want to convert ext4 to iomap interface sooner rather than later. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
