On Wed, 2024-07-17 at 13:31 +0200, Jan Kara wrote: > On Mon 15-07-24 08:48:56, Jeff Layton wrote: > > Add a high-level document that describes how multigrain timestamps work, > > rationale for them, and some info about implementation and tradeoffs. > > > > Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > One comment below. With that fixed feel free to add: > > Reviewed-by: Jan Kara <jack@xxxxxxx> > > > +Implementation Notes > > +==================== > > +Multigrain timestamps are intended for use by local filesystems that get > > +ctime values from the local clock. This is in contrast to network filesystems > > +and the like that just mirror timestamp values from a server. > > + > > +For most filesystems, it's sufficient to just set the FS_MGTIME flag in the > > +fstype->fs_flags in order to opt-in, providing the ctime is only ever set via > > +inode_set_ctime_current(). If the filesystem has a ->getattr routine that > > +doesn't call generic_fillattr, then you should have it call fill_mg_cmtime to > > +fill those values. > > I think you should explicitely mention that ->setattr() implementation > needs to use setattr_copy() or otherwise mimic its behavior... > > Honza I've added a sentence like you suggest to the patch in my tree. Thanks for all the reviews! -- Jeff Layton <jlayton@xxxxxxxxxx>
