On Fri, Oct 18, 2019 at 10:08:14AM +1100, Matthew Bobrowski wrote: > On Fri, Oct 18, 2019 at 08:56:13AM +1100, Dave Chinner wrote: > > On Thu, Oct 17, 2019 at 11:39:17AM -0700, Darrick J. Wong wrote: > > > On Thu, Oct 17, 2019 at 07:56:11PM +0200, Christoph Hellwig wrote: > > > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > > > > > When doing a direct IO that spans the current EOF, and there are > > > > written blocks beyond EOF that extend beyond the current write, the > > > > only metadata update that needs to be done is a file size extension. > > > > > > > > However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that > > > > there is IO completion metadata updates required, and hence we may > > > > fail to correctly sync file size extensions made in IO completion > > > > when O_DSYNC writes are being used and the hardware supports FUA. > > > > > > > > Hence when setting IOMAP_F_DIRTY, we need to also take into account > > > > whether the iomap spans the current EOF. If it does, then we need to > > > > mark it dirty so that IO completion will call generic_write_sync() > > > > to flush the inode size update to stable storage correctly. > > > > > > > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > > > > > Looks ok, but need fixes tag. Also, might it be wise to split off the > > > ext4 section into a separate patch so that it can be backported > > > separately? > > > > I 've done a bit more digging on this, and the ext4 part is not > > needed for DAX as IOMAP_F_DIRTY is only used in the page fault path > > and hence can't change the file size. As such, this only affects > > direct IO. Hence the ext4 hunk can be added to the ext4 iomap-dio > > patchset that is being developed rather than being in this patch. > > Noted, thanks Dave. I've incorporated the ext4 related change into my patch > series. Ok, I've dropped the ext4 hunk from my branch. --D > --<M>--
